KR20240144828A - Preparation method of dry electrode, Preparation device of dry electrode, Dry electrode and Lithium battery - Google Patents

Abstract

A method for manufacturing a dry electrode, an electrode manufacturing device, a dry electrode, and a lithium battery are provided, comprising: a step of providing a metal layer at a first speed (V1); a step of providing a dry electrode film at a second speed and intermittently providing the dry electrode film at a third speed that is lower than the second speed; and a step of intermittently disposing the dry electrode film on one or both surfaces of the metal layer to form a dry electrode active material layer, wherein the dry electrode film is disposed on the metal layer while the dry electrode film is provided at the second speed, and the dry electrode film is undisposed on the metal layer while the dry electrode film is provided at the third speed.

Description

Preparation method of dry electrode, Preparation device of dry electrode, Dry electrode and Lithium battery

The present invention relates to a method for manufacturing a dry electrode, a dry electrode manufacturing device, a dry electrode, and a lithium battery.

In order to meet the miniaturization and high performance of various devices, in addition to miniaturization and weight reduction of lithium batteries, high energy density is becoming important. In other words, high-capacity lithium batteries are becoming important.

Since electrodes manufactured from slurries containing solvents use excessive solvents during electrode manufacturing, dry methods that exclude the use of such organic solvents are being considered.

One aspect is to provide a method for manufacturing a dry electrode by intermittently coating an electrode active material layer on an electrode current collector.

Another aspect is to provide a dry electrode manufacturing device that intermittently coats an electrode active material layer on an electrode current collector.

Another aspect is to provide a dry electrode manufactured by the above method.

Another aspect is to provide a lithium battery comprising the above dry electrode.

On one side,

A step of providing a metal layer at a first speed;

A step of providing a dry electrode film at a second speed and intermittently providing a third speed that is lower than the second speed; and

A step of intermittently disposing the dry electrode film on one or both sides of the metal layer to form a dry electrode active material layer,

While providing the dry electrode film at the second speed, the dry electrode film is disposed on the metal layer,

A method for manufacturing a dry electrode is provided, wherein the dry electrode film is undisposed on the metal layer while the dry electrode film is provided at the third speed.

On the other hand,

It includes a first laminator roll and a second laminator roll which are arranged spaced apart from each other,

At least one of the first laminator roll and the second laminator roll has a second rotational peripheral speed and is configured or driven to intermittently have a third rotational peripheral speed that is smaller than the second rotational peripheral speed,

A dry electrode manufacturing device is provided, wherein the first laminator roll and the second laminator roll have opposite rotation directions.

On the other hand,

A dry electrode manufactured by the above method is provided.

On the other hand,

A lithium battery including a dry electrode according to the above is provided.

According to one aspect, a dry electrode having an electrode active material layer intermittently coated on an electrode current collector can be easily provided by intermittently supplying a dry electrode film on an electrode current collector.

Figures 1a to 1d are schematic diagrams showing a method for manufacturing a dry electrode using a dry electrode film according to Example 1.
Figure 1e is a plan view of the aluminum thin film used in Example 1.
Figure 1f is a plan view of the dry electrode manufactured in Example 1.
Figure 2 is a schematic diagram showing a method for manufacturing a dry electrode using a dry powder according to Comparative Example 2.
Figure 3 is a schematic diagram of a lithium battery according to an embodiment.
Figure 4 is a schematic diagram of a lithium battery according to an embodiment.
Figure 5 is a schematic diagram of a lithium battery according to an embodiment.
<Explanation of symbols for major parts of the drawing>
1, 1a, 1b lithium battery 2, 2a, 2b cathode
3, 3a, 3b positive electrode 4, 4a, 4b separator
5, 5a, 5b battery case 6, 6a, 6b cap assembly
7, 7a, 7b battery structure 8a, 8b electrode tab
10 No. 1 winding roll 20a No. 2-1 winding roll
20b 2-2 winding roll 30a 1st laminator roll
30b 2nd laminator roll 30 laminator roll
40, 40a, 40b guide roll 45 intake
50a, 50b, 50 knife 60 first dry mixture
100a, 100b, 100 dry electrode film 150a, 150b, 150 intermediate layer, carbon layer
200 metal layer, electrode current collector 300a, 300b, 300 dry electrode active material layer
400 dry electrode 500a first area
500b area 2

The present inventive concept described below can undergo various transformations and have various embodiments, and specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the present inventive concept to specific embodiments, but should be understood to include all transformations, equivalents, or substitutes included in the technical scope of the present inventive concept.

The terminology used below is only used to describe specific embodiments and is not intended to limit the present creative idea. The singular expression includes the plural expression unless the context clearly indicates otherwise. Hereinafter, the terms "comprises" or "has" and the like are intended to indicate the presence of a feature, number, step, operation, component, part, ingredient, material or a combination thereof described in the specification, but should be understood to not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, ingredients, materials or combinations thereof. The "/" used below may be interpreted as "and" or "or" depending on the context.

In order to clearly express various layers and regions in the drawings, the thickness is shown enlarged or reduced. Similar parts are designated by the same drawing reference numerals throughout the specification. When a part such as a layer, film, region, or plate is referred to as being “on” or “over” another part throughout the specification, this includes not only the case where it is directly above the other part, but also the case where there is another part in between. The terms first, second, etc. may be used throughout the specification to describe various components, but the components should not be limited by the terms. The terms are used only to distinguish one component from another. In the present specification and the drawings, components having substantially the same functional configuration are referred to by the same reference numerals, and redundant descriptions are omitted.

In the present disclosure, "dry" or "dry" means a state in which the conductive material is not intentionally in contact with a solvent such as a process solvent, or a state in which the conductive material is not intentionally in contact with a solvent. For example, a dry conductive material means a conductive material that is not intentionally in contact with a solvent or a conductive material that is not intentionally inclusive of a solvent. For example, a dry binder means a binder that is not intentionally in contact with a solvent or a binder that is not intentionally inclusive of a solvent. For example, a binder that is liquid at room temperature without being mixed with a solvent is a dry binder. For example, a dry electrode film means an electrode film that is not intentionally in contact with a solvent or an electrode film that is not intentionally inclusive of a solvent. For example, a dry electrode means an electrode that is not intentionally in contact with a solvent or an electrode that is not intentionally inclusive of a solvent. For example, a dry electrode active material layer means an electrode active material layer that is not intentionally in contact with a solvent or an electrode active material layer that is not intentionally inclusive of a solvent.

In the present disclosure, the "size" or "particle diameter" of a particle refers to the average diameter when the particle is spherical, and the average major axis length when the particle is non-spherical. The particle diameter of a particle can be measured using a particle size analyzer (PSA). The "particle diameter" of a particle is, for example, the average particle diameter. The average particle diameter is, for example, the median particle diameter (D50). The median particle diameter (D50) is the size of a particle corresponding to 50% of the cumulative volume, calculated from the side of particles having a small particle size in a size distribution of particles measured by, for example, laser diffraction.

As used herein, “metal” includes both metals and metalloids such as silicon and germanium, in either an elemental or ionic state.

As used herein, “alloy” means a mixture of two or more metals.

In the present disclosure, “positive electrode active material” means a positive electrode material capable of undergoing lithiation and delithiation.

In the present disclosure, “negative electrode active material” means a negative electrode material capable of undergoing lithiation and delithiation.

In the present disclosure, “lithiation” and “lithiate” mean a process of adding lithium to a positive electrode active material or a negative electrode active material.

In the present disclosure, “delithiation” and “delithiate” mean a process of removing lithium from a positive electrode active material or a negative electrode active material.

In this disclosure, “charging” and “charging” mean a process of providing electrochemical energy to a battery.

In this disclosure, “discharging” and “discharging” mean the process of removing electrochemical energy from a battery.

In the present disclosure, “positive electrode” and “cathode” mean an electrode at which electrochemical reduction and lithiation occur during a discharge process.

In the present disclosure, “cathode” and “anode” mean electrodes at which electrochemical oxidation and delithiation occur during a discharge process.

Below, a method for manufacturing a dry electrode according to exemplary embodiments is described in more detail.

A method for manufacturing a dry electrode according to one embodiment comprises the steps of: providing a metal layer at a first speed; providing a dry electrode film at a second speed and intermittently providing the dry electrode film at a third speed that is lower than the second speed; and intermittently disposing the dry electrode film on one or both sides of the metal layer to form a dry electrode active material layer, wherein the dry electrode film is disposed on the metal layer while the dry electrode film is provided at the second speed, and the dry electrode film is undisposed on the metal layer while the dry electrode film is provided at the third speed.

By supplying a dry electrode film on one or both sides of a metal layer at a speed substantially the same as the supply speed of the metal layer and intermittently reducing the supply speed to a lower supply speed than the supply speed of the metal layer, a dry electrode including a plurality of dry electrode active material layers spaced apart from each other and a non-conductive region disposed between the plurality of dry electrode active material layers can be easily manufactured by discontinuously or intermittently disposing dry electrode active material layers on one or both sides of a metal layer (200). By controlling the speed at which the dry electrode film is supplied, the length of the dry electrode active material layer disposed on the metal layer and/or the distance between adjacent dry electrode active material layers can be easily controlled. In addition, various patterns of dry electrode active material layers can be introduced on the metal layer.

In contrast, a conventional dry electrode manufacturing method sequentially arranges a dry electrode film on one or both sides of an electrode current collector, and then removes a portion of the dry electrode film to introduce a non-conductive portion in which the electrode current collector is exposed between a plurality of dry electrode active material layers. Therefore, the dry electrode manufacturing process becomes complicated by additionally including a step of removing the dry electrode film. In addition, for example, in a dry electrode in which a portion of the electrochemical electrode film is removed using a laser or the like, defects such as burrs and/or depressions may be introduced between the dry electrode active material layer and the current collector. When a lithium battery equipped with a dry electrode including such defects is charged and discharged, side reactions due to such defects may increase, which may deteriorate the cycle characteristics of the lithium battery.

A method for manufacturing a dry electrode according to an embodiment of the present invention is described with reference to the drawings.

A method for manufacturing a dry electrode (400) includes: a step of providing a metal layer (200) at a first speed (V1); a step of providing a dry electrode film (100, 100a, 100b) at a second speed (V2) and intermittently providing a third speed (V3) lower than the second speed (V2); and a step of intermittently disposing the dry electrode film (100, 100a, 100b) on one or both sides of the metal layer (200) to form a dry electrode active material layer (300, 300a, 300b). While the dry electrode film (100, 100a, 100b) is provided at the second speed (V2), the dry electrode film (100, 100a, 100b) is disposed on the metal layer (200). Meanwhile, while the dry electrode film is provided at the third speed (V3), the dry electrode film (100, 100a, 100b) is not placed on the metal layer (200).

Referring to FIGS. 1A to 1D, first, a metal layer (200) is provided at a first speed (V1).

The metal layer (200) is, for example, wound on a first winding roll (10) and then continuously provided from the first winding roll (10) at a first speed (V1).

The metal layer (200) may be provided at a constant rate, for example. The rate at which the metal layer (200) is provided may be, for example, the manufacturing rate of the dry electrode (400). The rate at which the metal layer (200) is provided may be adjusted according to the required manufacturing rate of the dry electrode (400). The metal layer (200) is, for example, an electrode current collector.

Next, the dry electrode film (100, 100a, 100b) is provided at a second speed (V2) and the dry electrode film (100, 100a, 100b) is intermittently provided at a third speed (V3) which is lower than the second speed (V2).

The dry electrode film (100, 100a, 100b) is, for example, wound on the 2-1 winding roll (20a) and then provided from the 2-1 winding roll (20a) at a second speed (V2). While the dry electrode film (100, 100a, 100b) is provided at the second speed (V2), the dry electrode film (100, 100a, 100b) is intermittently provided at a reduced third speed (V3). The dry electrode film (100, 100a, 100b) may be sequentially and alternately provided in this order of the second speed (V2) and the third speed (V3) from the 2-1 winding roll (20a), for example. The dry electrode film (100, 100a, 100b) includes a cycle in which, for example, it is provided at a second speed (V2), then decelerated to a third speed (V3), then increased to the second speed (V2), and then provided, and this cycle can be repeated multiple times. As a result, the speed at which the dry electrode film (100, 100a, 100b) is provided can be alternately changed between the second speed (V2) and the third speed (V3). The first speed (V1) at which the metal layer (200) is provided can be, for example, the speed at which the dry electrode (400) is provided. The first speed (V1) at which the metal layer (200) is provided is not particularly limited and can be changed according to required conditions. The first velocity (V1) can be, for example, 0.001 m/s to 10 m/s, 0.01 m/s to 10 m/s, 0.1 m/s to 10 m/s or 0.1 m/s to 1 m/s.

The first speed (V1) providing the metal layer (200) may be, for example, the same as the second speed (V2) providing the dry electrode film (100, 100a, 100b). The second speed (V2) may be, for example, 95 to 105 %, 97 to 103 %, 99 to 101 %, or 100 % of the first speed (V1). The first speed (V1) and the second speed (V2) may be controlled within a range that does not deteriorate the properties of the lithium battery including the dry electrode film (100, 100a, 100b).

The third speed (V3) providing the dry electrode film (100, 100a, 100b) can be 0% to less than 100%, 10% to less than 100%, 10% to 90%, 10% to 80%, 20% to 80%, 20% to 70%, or 30% to 70% of the second speed (V2). Since the dry electrode film (100, 100a, 100b) is supplied onto the metal layer (200) at the third speed (V3) in this range, a non-coated portion on the metal layer (200) where the dry electrode film (100, 100a, 100b) is not disposed can be intermittently and easily introduced. As a result, the possibility of defect formation is reduced during the process of manufacturing a lithium battery from a dry electrode (400) having such a structure, thereby further improving the cycle characteristics of a lithium battery equipped with such a dry electrode.

If the third speed (V3) is too close to the second speed (V2), the change in the supply speed of the dry electrode film (100, 100a, 100b) is small, so that it is not easy to introduce a non-conductive region and it may be difficult to introduce various patterns. If the third speed (V3) is too small compared to the second speed (V2), the gap between the dry electrode active material layers (300, 300a, 300b) may increase excessively, so that the utilization of the metal layer (200) may be excessively reduced.

In addition, by controlling the third speed (V3), it is possible to intermittently and easily introduce a non-conductive region having various gaps between the dry electrode active material layers (300, 300a, 300b) in a continuous process. Accordingly, electrodes having various patterns can be continuously manufactured in one electrode manufacturing process, thereby improving the electrode manufacturing efficiency.

Next, a dry electrode film (100, 100a, 100b) is intermittently placed on one or both sides of the metal layer (200) to form a dry electrode active material layer (300, 300a, 300b).

For example, a dry electrode film (100, 100a, 100b) is placed on a metal layer (200) while providing the dry electrode film (100, 100a, 100b) at a second speed (V2).

By having the first speed (V1) for providing the metal layer (200) and the second speed (V2) for providing the dry electrode film (100, 100a, 100b) have the same first speed (V1), for example, the dry electrode film (100, 100a, 100b) can be disposed on the metal layer (200) to form a dry electrode active material layer (300, 300a, 300b).

For example, a metal layer (200) supplied from a first take-up roll (10) at a first speed (V1) is passed between a pair of first laminator rolls (30a) and second laminator rolls (30b) spaced apart at a regular interval. Then, a dry electrode film (100, 100a, 100b) supplied from a second-first take-up roll (20a) at a second speed (V2) is supplied to the first laminator roll (30a), and then disposed on one surface of the metal layer (200) by the first laminator roll (30a) to form a dry electrode active material layer (300a).

Intermittently, while providing the dry electrode film (100, 100a, 100b) at a third speed (V3), the dry electrode film (100, 100a, 100b) is not disposed on the metal layer (200).

Since the metal layer (200) is provided at a first speed (V1) and the dry electrode film (100, 100a, 100b) is provided at a third speed (V3) that is lower than, for example, the second speed (V2), the dry electrode film (100, 100a, 100b) may not be disposed on the metal layer (200). The first speed (V1) at which the metal layer (200) is provided is higher than, for example, the third speed (V3) at which the dry electrode film (100, 100a, 100b) is provided.

When the supply speed of the dry electrode film (100, 100a, 100b) is reduced from the second speed (V2) to the third speed (V3), the movement distance of the dry electrode film (100, 100a, 100b) supplied from the first laminator roll (30a) onto the metal layer (200) is reduced compared to the movement distance of the metal layer (200) between the pair of first laminator rolls (30a) and second laminator rolls (30b) for a certain time interval, so that a non-coated portion not including the dry electrode film (100, 100a, 100b) may be formed on the metal layer (200) due to the difference in the movement distance.

For example, a metal layer (200) supplied from a first take-up roll (10) at a first speed (V1) is passed between a pair of first laminate rolls (30a) and second laminate rolls (30b) spaced apart at a regular interval, and a dry electrode film (100a) supplied from a second-first take-up roll (20a) at a second speed (V2) is supplied to the first laminate roll (30a). Then, the dry electrode film (100a) is disposed on one surface of the metal layer (200) by the first laminator roll (30a) to form a dry electrode active material layer (300a). Next, by reducing the rotation speed of the first laminator roll (30a) to reduce the supply speed of the dry electrode film (100, 100a, 100b) to a third speed (V3), an area where the dry electrode film (100a) is not supplied on the metal layer (200), i.e., a non-coated area, can be formed. For example, when the third speed (V3) is reduced to 0, the supply of the dry electrode film (100a) on the metal layer (200) passing between the first laminator roll (30a) and the second laminator roll (30b) is cut off, so that while the supply of the electrochemical electrode film (100a) is cut off, an non-coated area that does not include the dry electrode active material layer (300a) disposed on the metal layer (200) can be formed.

Next, by increasing the speed of providing the dry electrode film (100, 100a, 100b) to a second speed (V2) again, the dry electrode film (100, 100a, 100b) can be disposed on the metal layer (200) while providing the dry electrode film (100, 100a, 100b) at the second speed (V2) which is the same speed as the speed of providing the metal layer (200).

After the step of supplying the dry electrode film (100, 100a, 100b) at the third speed (V3), when the supply speed of the dry electrode film (100, 100a, 100b) is increased from the third speed (V3) to the second speed (V2), the dry electrode film (100, 100a, 100b) is supplied at the same first speed (V1) as the metal layer (200). Therefore, the dry electrode film (100, 100a, 100b) can be disposed on the metal layer (200) supplied at the same first speed (V1) to form a dry electrode active material layer.

By intermittently supplying the dry electrode film (100, 100a, 100b) at a second speed (V2) and at a third speed (V3), a non-coated region in which the metal layer (200) is intermittently exposed can be formed between the dry electrode active material layers (300, 300a, 300b) disposed on the metal layer (200).

By alternately supplying dry electrode films (100, 100a, 100b) at a second speed (V2) and a third speed (V3), a plurality of dry electrode active material layers can be arranged spaced apart from each other on a metal layer (200).

By controlling the third speed (V3), the gap between the dry electrode active material layers that are arranged spaced apart from each other can be controlled. As a result, dry electrode active material layers having various patterns can be introduced onto the metal layer (200).

Referring to FIGS. 1A to 1D, the dry electrode film (100, 100a, 100b) may be, for example, a self-standing film. The dry electrode film (100, 100a, 100b) may, for example, maintain a film form without a support. By using the dry electrode film (100, 100a, 100b) in the form of a self-standing film, the dry electrode film (100, 100a, 100b) may be provided in various directions and in various ways. Since the dry electrode film (100, 100a, 100b) is a self-standing film, the dry electrode film (100, 100a, 100b) may be provided without a separate support. The dry electrode film (100, 100a, 100b) can be connected without a separate support, for example, between the 2-1 winding roll (20a) and the guide roll (40a). Since the dry electrode film (100, 100a, 100b) is a self-supporting film, the distance between the point where the dry electrode film (100, 100a, 100b) and the metal layer (200) join from the 2-1 winding roll (20a) on which the dry electrode film (100, 100a, 100b) is wound can be freely selected.

Referring to FIGS. 1A to 1C, the dry electrode film (100, 100a, 100b) may further include, for example, one or more cutting lines (CL, CL1, CL2) introduced along a direction orthogonal to the longitudinal direction of the dry electrode film (100, 100a, 100b) (i.e., axial direction). By introducing the cutting lines (CL, CL1, CL2) into the dry electrode film (100, 100a, 100b), separation of the dry electrode film (100, 100a, 100b) can be easily performed in a region where the speed of the dry electrode film (100, 100a, 100b) decreases. The number of cutting lines (CL, CL1, CL2) may be one or more. The number of cutting lines (CL, CL1, CL2) may be one, for example. The number of cutting lines (CL, CL1, CL2) can be, for example, two. The distance between the two cutting lines (CL, CL1, CL2) can be a distance corresponding to the spacing between the dry electrode active material layers (300, 300a, 300b). The distance between two adjacent cutting lines (CL, CL1, CL2) can be, for example, 0.1 ㎛ to 10 cm, 1 ㎛ to 5 cm, 10 ㎛ to 1 cm, or 100 ㎛ to 1 cm.

The dry electrode film (100, 100a, 100b) including the cutting lines (CL, CL1, CL2) may be supported by a support, for example, before being placed on the metal layer (200). The support may be, for example, a laminator roll (30, 30a, 30b), but is not necessarily limited thereto, and any support that supports the dry electrode film (100, 100a, 100b) may be used. While the dry electrode film (100, 100a, 100b) is supported by a support, the dry electrode film (100, 100a, 100b) can be cut along a direction orthogonal to the longitudinal direction (i.e., axial direction) of the dry electrode film (100, 100a, 100b) by, for example, a knife (50, 50a, 50b), thereby introducing cutting lines (CL, CL1, CL2) into the dry electrode film (100, 100a, 100b). The axial length of the cutting lines (CL, CL1, CL2) can be, for example, the same as the widthwise length of the dry electrode film (100, 100a, 100b). Dry electrode films (100, 100a, 100b) may be in a state where adjacent dry electrode films (100, 100a, 100b) are separated from each other by the cutting lines (CL, CL1, CL2) on the support.

Referring to FIGS. 1A to 1E, the metal layer (200) may further include, for example, an interlayer (150, 150a, 150b) disposed on one or both surfaces of the metal layer (200). The step of providing the metal layer (200) at the first speed (V1) may further include a step of disposing an interlayer (150, 150a, 150b) on the metal layer (200).

For example, the step of disposing an intermediate layer (150, 150a, 150b) on the metal layer (200) may be further included before the step of providing the metal layer (200) at the first speed (V1) or while performing the step of providing the metal layer (200) at the first speed (V1). By additionally disposing the intermediate layer (150, 150a, 150b) on the metal layer (200), the position at which the dry electrode film (100, 100a, 100b) is disposed on the metal layer (200) can be more easily controlled. The method of disposing the intermediate layer (150, 150a, 150b) on the metal layer (200) is not particularly limited. The intermediate layer (150, 150a, 150b) may be disposed by, for example, a dry method, a wet method, etc. The intermediate layers (150, 150a, 150b) may be intermittently arranged on the metal layer (200). For example, the intermediate layers (150, 150a, 150b) may be intermittently arranged along the longitudinal direction of the metal layer (200). For example, the intermediate layers (150, 150a, 150b) may be arranged spaced apart at regular intervals along the longitudinal direction of the metal layer (200).

The interlayer (150, 150a, 150b) is, for example, directly disposed on one side or both sides of the metal layer (200). Therefore, another layer may not be disposed between the metal layer (200) and the interlayer (150, 150a, 150b). By directly disposing the interlayer (150, 150a, 150b) on one side or both sides of the metal layer (200), the bonding strength between the metal layer (200) and the dry electrode film (100, 100a, 100b) or the metal layer (200) and the dry electrode active material layer can be further improved.

The metal layer (200) may include, for example, a plurality of first regions (500a) spaced apart from each other along the longitudinal direction of the metal layer (200) and one or more second regions (500b) intermittently arranged between the plurality of first regions (500a). An intermediate layer (150, 150a, 150b) may be selectively arranged in the first region (500a) among the first regions (500a) and the second regions (500b) of the metal layer (200). The intermediate layer (150, 150a, 150b) may not be arranged (undisposed) in the second region (500b) of the metal layer (200). Since the intermediate layer (150, 150a, 150b) is not arranged in the second region (500b), the second region (500b) is a non-coated portion where the metal layer (200) is exposed. Since the intermediate layer (150, 150a, 150b) is selectively disposed only in the first region (500a) of the metal layer (200), the dry electrode film (100, 100a, 100b) can be more easily selectively disposed on the metal layer (200).

Referring to FIG. 1e, the area of the first region (500a) may be 99.99% or less, 99.9% or less, 99% or less, 95% or less, 90% or less, or 80% or less of the total area of the metal layer (200). The area of the first region (500a) may be 10 to 99.99%, 30 to 99.9%, 50 to 99%, 50 to 95%, 50 to 90%, or 50 to 80% of the total area of the metal layer (200). When the first region (500a) has an area in this range, the energy density of the dry electrode may be improved.

The first regions (500a) can be arranged spaced apart from each other, for example, along the longitudinal direction of the dry electrode. Since the first regions (500a) are arranged spaced apart from each other, for example, along the longitudinal direction of the metal layer (200), a plurality of electrode plates can be easily manufactured by cutting between adjacent first regions (500a).

The first regions (500a) can be arranged at equal intervals along the longitudinal direction of the metal layer (200), for example. Since the first regions (500a) are arranged at equal intervals along the longitudinal direction of the metal layer (200), for example, a plate having a uniform size can be easily mass-produced.

Alternatively, the first regions (500a) may be arranged at non-uniform intervals, for example, along the longitudinal direction of the metal layer (200). By arranging the first regions (500a) at non-uniform intervals, for example, along the longitudinal direction of the metal layer (200), dry electrodes having various patterns can be manufactured.

Referring to FIG. 1e, a ratio (L1/L2) of the length (L1) of each of the plurality of first regions (500a) spaced apart from each other along the longitudinal direction of the metal layer (200) and the spacing (L2) between adjacent plurality of first regions (500a) may be, for example, 10 to 1000, 10 to 500, 10 to 200, or 10 to 100. When the ratio of the length (L1) of each of the plurality of first regions (500a) spaced apart from each other along the longitudinal direction of the metal layer (200) and the spacing (L2) between adjacent plurality of first regions (500a) has this range, the energy density of the dry electrode manufactured can be improved.

The spacing (L2) between a plurality of first regions (500a) spaced apart along the longitudinal direction of the metal layer (200) may be smaller than the width (W1) of the metal layer (200).

The ratio (L2/W) of the spacing (L2) between the plurality of first regions (500a) spaced apart along the longitudinal direction of the metal layer (200) and the width (W1) of the metal layer (200) may be, for example, 0.01 to 0.9, 0.01 to 0.8, 0.01 to 0.5, 0.01 to 0.3, or 0.01 to 0.1.

The energy density of the dry electrode manufactured by having a ratio of the spacing (L2) between a plurality of first regions (500a) spaced apart along the longitudinal direction of the metal layer (200) and the width (W1) of the metal layer (200) within this range can be improved.

Referring to FIGS. 1a, 1b and 1d, a metal layer (200) may be provided at a first speed (V1) and a dry electrode film (100, 100a, 100b) may be disposed on an intermediate layer (150, 150a, 150b) of a first region (500a) while the dry electrode film (100, 100a, 100b) is provided at a second speed (V2) that is the same as the first speed (V1).

Referring to FIG. 1c, while the metal layer (200) is provided at a first speed (V1) and the dry electrode film (100, 100a, 100b) is provided at a third speed (V3) lower than the first speed (V1), the dry electrode film (100, 100a, 100b) may be undisposed in the second region (500b) of the metal layer (200). For example, while the metal layer (200) is provided at a first speed (V1) and the dry electrode film (100, 100a, 100b) is provided at a third speed (V3) lower than the first speed (V1), the dry electrode film (100, 100a, 100b) may be spaced from the surface of the second region (500b) of the metal layer (200). Therefore, the dry electrode film (100, 100a, 100b) may not be disposed on the second region (500b) of the metal layer (200).

Referring to FIG. 1f, the total area of the dry electrode active material layer (300b) may be 99.99% or less, 99.9% or less, 99% or less, 95% or less, 90% or less, or 80% or less of the total area of the dry electrode (400). The total area of the dry electrode active material layer (300b) may be 10 to 99.99%, 30 to 99.9%, 50 to 99%, 50 to 95%, 50 to 90%, or 50 to 80% of the total area of the dry electrode (400). When the dry electrode active material layer has a total area in this range, the energy density of the dry electrode may be improved.

The dry electrode active material layers (300, 300a, 300b) can be arranged spaced apart from each other along the length direction of the dry electrode, for example. Since the dry electrode active material layers (300, 300a, 300b) are arranged spaced apart from each other along the length direction of the dry electrode, a plurality of electrode plates can be easily manufactured by cutting between adjacent dry electrode active material layers.

The dry electrode active material layers (300, 300a, 300b) can be arranged at uniform intervals along the longitudinal direction of the dry electrode, for example. Since the dry electrode active material layers are arranged at uniform intervals along the longitudinal direction of the dry electrode, it is possible to easily mass-produce electrode plates having a uniform size.

Referring to FIGS. 1A to 1D, the dry electrode active material layers (300, 300a, 300b) may be arranged at equal intervals along the length direction of the dry electrode by a first distance (MD1), for example.

Referring to FIGS. 1A to 1C, the dry electrode film (100, 100a, 100b) may further include, for example, a plurality of cutting lines (CL, CL1, CL2) introduced along a direction orthogonal to the longitudinal direction of the dry electrode film (100, 100a, 100b) (i.e., an axial direction). By introducing a plurality of cutting lines (CL, CL1, CL2) to the dry electrode film (100, 100a, 100b), separation of the dry electrode film (100, 100a, 100b) can be performed more easily in a region where the speed of the dry electrode film (100, 100a, 100b) decreases. The plurality of cutting lines (CL, CL1, CL2) include, for example, a first cutting line (CL1) and a second cutting line (CL2), and the first cutting line (CL1) and the second cutting line (CL2) can be spaced apart from each other by a second distance (MD2, MD2A, MD2B). The distance between the plurality of cutting lines (CL, CL1, CL2), that is, the second distance (MD2, MD2A, MD2B), can be, for example, 10 % to less than 100 %, 10 % to 90 %, 10 % to 80 %, 20 % to 80 %, 20 % to 70 %, or 30 % to 70 % of the first distance (MD1). The second distance (L3, L3A, L3B) may be, for example, 0.1 ㎛ to 10 cm, 1 ㎛ to 5 cm, 10 ㎛ to 1 cm, or 100 ㎛ to 1 cm. As the first distance (MD1) decreases, the energy density of the dry electrode may be improved. As the second distance (MD2, MD2A, MD2B) decreases, the proportion of the dry electrode film (100, 100a, 100b) that is discarded may decrease, so that the utilization rate of the dry electrode film (100, 100a, 100b) may be improved.

Alternatively, although not shown in the drawing, the dry electrode active material layers (300, 300a, 300b) may be arranged at non-uniform intervals, for example, along the longitudinal direction of the dry electrode. By arranging the dry electrode active material layers (300, 300a, 300b) at non-uniform intervals, for example, along the longitudinal direction of the dry electrode, dry electrodes having various patterns can be manufactured.

Referring to FIG. 1f, a ratio (L3/L4) of the length (L3) of each of the dry electrode active material layers spaced apart from each other along the longitudinal direction of the dry electrode and the gap (L4) between adjacent dry electrode active material layers can be, for example, 10 to 1000, 10 to 500, 10 to 200, or 10 to 100. When the length (L3) of each of the dry electrode active material layers spaced apart from each other along the longitudinal direction of the dry electrode and the gap (L4) between adjacent dry electrode active material layers have a ratio within this range, the energy density of the dry electrode manufactured can be improved.

The gap (L2) between the dry electrode active material layers spaced apart along the length direction of the dry electrode may be smaller than the width (W2) of the dry electrode.

The ratio (L2/W2) of the spacing between the dry electrode active material layers spaced apart along the length direction of the dry electrode and the width (W2) of the dry electrode can be, for example, 0.01 to 0.9, 0.01 to 0.8, 0.01 to 0.5, 0.01 to 0.3 or 0.01 to 0.1.

The energy density of the dry electrode can be improved when the ratio (L2/W2) of the gap between the dry electrode active material layers spaced apart along the length direction of the dry electrode and the width (W2) of the dry electrode has a ratio within this range.

Since the dry electrode film (100, 100a, 100b) is selectively placed on the metal layer (200), the step of removing the dry electrode film (100, 100a, 100b) from the metal layer (200) may not be included.

In a conventional dry electrode manufacturing method, a dry electrode film (100, 100a, 100b) is disposed over the entire metal layer (200), and then a portion of the dry electrode film (100, 100a, 100b) is selectively removed. In contrast, in a dry electrode manufacturing method according to the present embodiment, since the dry electrode film (100, 100a, 100b) is selectively disposed on the metal layer (200), an additional dry electrode film (100, 100a, 100b) removal step can be omitted, thereby simplifying the overall process and preventing additional defects occurring in the dry electrode film (100, 100a, 100b) removal step.

A burr or a depression may not exist on one surface of a second region (500b) disposed adjacent to a first region (500a) of a metal layer (200). For example, a burr or a depression may be free on one surface of a metal layer (200) disposed adjacent to one side of a dry electrode active material layer and not covered by the dry electrode active material layer.

When the dry electrode film (100, 100a, 100b) is disposed over the entire metal layer (200) and then the dry electrode film (100, 100a, 100b) of the second region (500b) is removed by laser cutting, a defect such as a burr and/or a depression caused by laser cutting may be formed near the boundary between the first region (500a) and the second region (500b) of the dry electrode film (100, 100a, 100b) disposed on the first region (500a) of the metal layer (200). A dry electrode including such a defect may cause the cycle characteristics of the lithium battery to deteriorate due to an increase in internal resistance and/or an increase in side reactions, for example, due to separation of the dry electrode film (100, 100a, 100b) from the electrode current collector during charging and discharging of the lithium battery. In contrast, the dry electrode manufacturing method according to the present embodiment can omit the step of removing the dry electrode film (100, 100a, 100b), thereby preventing deterioration of the lithium battery due to defects such as burrs and/or depressions formed during laser cutting.

The step of forming a dry electrode active material layer may include, for example, a step of laminating a dry electrode film (100, 100a, 100b) and a metal layer (200). The step of forming a dry electrode active material layer may be performed, for example, by laminating a dry electrode film (100, 100a, 100b) and a metal layer (200). The dry electrode active material layer may be formed by laminating a dry electrode film (100, 100a, 100b) and a metal layer (200). The dry electrode active material layer may be laminated on the metal layer (200), for example, by bonding with an intermediate layer (150, 150a, 150b).

The lamination of the dry electrode film (100, 100a, 100b) and the metal layer (200) can be performed, for example, by passing the dry electrode film (100, 100a, 100b) and the metal layer (200) between a pair of rolls.

A pair of rolls may be, but is not limited to, a pair of calendar rolls, a pair of guide rolls, a pair of lamination rolls, etc., and any roll capable of laminating a dry electrode film (100, 100a, 100b) and a metal layer (200) may be used.

A pair of rolls may perform the functions of more than one of a calendar roll, a guide roll, and a lamination roll. For example, a pair of guide rolls may perform the functions of both a guide roll and a lamination roll.

The step of forming a dry electrode active material layer may further include, for example, a step of applying heat, pressure, or a combination thereof to at least one of the dry electrode films (100, 100a, 100b) and the metal layer (200). The step of forming a dry electrode active material layer may be formed, for example, by additionally applying heat, pressure, or a combination thereof to at least one of the dry electrode films (100, 100a, 100b) and the metal layer (200).

For example, a metal layer (200) is provided from a first winding roll (10), a dry electrode film (100, 100a, 100b) is provided from a second roll, and as the metal layer (200) and the dry electrode film (100, 100a, 100b) pass through a pair of rolls, the metal layer (200) and the dry electrode film (100, 100a, 100b) can be laminated to each other by heat, pressure, or a combination thereof applied by a pair of rolls to form a dry electrode active material layer.

For example, a metal layer (200) including an intermediate layer (150, 150a, 150b) selectively arranged in a first region (500a) is provided from a first winding roll (10), a dry electrode film (100, 100a, 100b) is provided from a second roll, and as the metal layer (200) and the dry electrode film (100, 100a, 100b) pass through a pair of rolls, a dry electrode film is arranged on the intermediate layer (150, 150a, 150b) by heat, pressure, or a combination thereof applied by a pair of rolls, and at the same time, they are laminated to form a dry electrode active material layer.

The range of heat, pressure or a combination thereof used in the step of applying heat, pressure or a combination thereof can be selected within a range that forms a dry electrode active material layer without cracking and is not particularly limited. The temperature of a pair of rolls can be, for example, 0 to 100° C. or 10 to 50° C. The pressure applied to the dry electrode by a pair of rolls can be, for example, 0 to 100 MPa, 1 Pa to 10 MPa or 10 Pa to 1 MPa.

The step of forming a dry electrode active material layer (300, 300a, 300b) may include, for example, a step of simultaneously providing a dry electrode film (100, 100a, 100b) and the metal layer (200) between a first laminator roll (30a) and a second laminator roll (30b).

Referring to FIGS. 1A to 1D, a metal layer (200) is provided from a first winding roll (10), a dry electrode film (100, 100a, 100b) is provided from a second-first winding roll (20a), and when the metal layer (200) and the dry electrode film (100, 100a, 100b) pass between at least one pair of lamination rolls, the metal layer (200) and the dry electrode film (100, 100a, 100b) can be laminated with each other to form a dry electrode active material layer (300, 300a, 300b). For example, a pair of guide rolls (40, 40a, 40b) can be additionally arranged before a pair of lamination rolls (30, 30a, 30b). The dry electrode film (100, 100a, 100b) may be placed on the metal layer (200) while passing between at least one pair of guide rolls (40, 40a, 40b) before the metal layer (200) and the dry electrode film (100, 100a, 100b) pass between at least one pair of lamination rolls (30, 30a, 30b).

For example, a metal layer (200) is provided from a first winding roll (10), a dry electrode film (100, 100a, 100b) is provided from a second-first winding roll (20a), and when the metal layer (200) and the dry electrode film (100, 100a, 100b) pass through a first guide roll (40a) and a second guide roll (40b), a dry electrode film is placed on the metal layer (200), and then when the metal layer (200) passes between a first lamination roll (30a) and a second lamination roll (30b), the metal layer (200) and the dry electrode film (100, 100a, 100b) are laminated to each other to form a dry electrode active material layer.

For example, a metal layer (200) including an intermediate layer (150, 150a, 150b) selectively arranged in a first region (500a) is provided from a first winding roll (10), a dry electrode film (100, 100a, 100b) is provided from a second-first winding roll (20a), and while the metal layer (200) and the dry electrode film (100, 100a, 100b) pass between the first lamination roll and the second lamination roll, the dry electrode film is arranged on the intermediate layer (150, 150a, 150b) and simultaneously laminated with each other to form a dry electrode active material layer.

At least one of the first laminator roll (30a) and the second laminator roll (30b) may further include an intake port (45) for mechanically attaching, for example, a dry electrode film (100, 100a, 100b) to at least one of the first laminator roll (30a) and the second laminator roll (30b).

A plurality of intake ports (45) may be arranged on at least one surface of the first laminator roll (30a) and the second laminator roll (30b). The plurality of intake ports (45) may serve to attach the dry electrode film (100, 100a, 100b) to at least one surface of the first laminator roll (30a) and the second laminator roll (30b). The intake ports (45) may mechanically attach the dry electrode film (100, 100a, 100b) to at least one surface of the first laminator roll (30a) and the second laminator roll (30b), for example, by vacuum. By controlling the size of the vacuum applied to the intake port (45), the dry electrode film (100, 100a, 100b) can be easily attached and/or detached from the surface of at least one of the first laminator roll (30a) and the second laminator roll (30b). For example, if the pressure of the vacuum applied to the intake port (45) is less than the atmospheric pressure, the dry electrode film (100, 100a, 100b) is easily attached to the surface of at least one of the first laminator roll (30a) and the second laminator roll (30b). For example, if the pressure of the vacuum applied to the intake port (45) is greater than the atmospheric pressure, the dry electrode film (100, 100a, 100b) is easily detached from at least one of the first laminator roll (30a) and the second laminator roll (30b).

In the process of reducing the speed of the dry electrode film (100, 100a, 100b) from the second speed (V2) to the third speed (V3) by attaching the dry electrode film (100, 100a, 100b) to at least one surface of the first laminator roll (30a) and the second laminator roll (30b), the dry electrode film (100, 100a, 100b) is separated, but one end of the separated dry electrode film (100, 100a, 100b) remains attached to the metal layer (200), and the other end remains attached to at least one surface of the first laminator roll (30a) and the second laminator roll (30b), thereby enabling the dry electrode manufacturing process to be continuously performed.

The dry electrode film (100, 100a, 100b) may further include one or more cutting lines formed along the machine direction while attached to, for example, one or more of the first laminator roll (30a) and the second laminator roll (30b). Since the dry electrode film (100, 100a, 100b) further includes cutting lines, the separation of the dry electrode film (100, 100a, 100b) can be performed more easily in the process of reducing the speed of the dry electrode film (100, 100a, 100b) from the second speed (V2) to the third speed (V3).

The roll used in the manufacture of the dry electrode may not include an opening having a length. A guide roll, a lamination roll, a calender roll, etc. used in the manufacture of the dry electrode may not include an opening having a length. The length of the opening may be a length arranged along the width direction of the dry electrode. At least one of the first laminator roll (30a) and the second laminator roll (30b) may not include an opening having a length formed along, for example, an axial direction (TD, transverse direction). Since the roll used in the manufacture of the dry electrode does not include an opening, a uniform pressure can be applied to the dry electrode active material layer when forming the dry electrode active material layer.

The dry electrode (400) illustrated in FIG. 1f can be manufactured by the following method using, for example, the metal layer (200) illustrated in FIG. 1e.

Referring to FIG. 1a, while passing a first region (500a) of a metal layer (200) between a first laminator roll (30a) and a second laminator roll (30b) at a first speed (V1), a dry positive electrode film (100a) is supplied from the first laminator roll (30a) onto a carbon layer (150a) of the first region (500a) of the metal layer (200) at a second speed (V2) that is the same as the first speed (V1), thereby laminating the dry positive electrode film (100a) onto one surface of the metal layer (200) and disposing a dry electrode active material layer (300a) on one surface of the metal layer (200). Before supplying the second region (500b) adjacent to the first region (500a) of the metal layer (200) between the first laminator roll (30a) and the second laminator roll (30b), a dry positive electrode film (100a) corresponding to the machine direction length (MD1) of the second region (500b) of the metal layer (200) is attached to the surface of the first laminator roll (30a), and a first cutting line (CL1) and a second cutting line (CL2) are simultaneously introduced into the dry positive electrode film (100a) by a pair of knives (50, 50a, 50b) spaced apart by a length (MD2A) corresponding to 50% of the machine direction length (MD1) of the second region (500b).

Referring to Fig. 1b, compared to Fig. 1a, the second region (500b) adjacent to the first region (500a) moves closer between the first laminator roll (30a) and the second laminator roll (30b). The first cutting line (CL1) of the dry positive electrode film (100a) is adjusted to coincide with the boundary line between the first region (500a) and the second region (500b).

Referring to FIG. 1C, from the time point of introducing the second region (500b) of the metal layer (200) between the first laminator roll (30a) and the second laminator roll (30b), the speed at which the dry positive electrode film (100a) is supplied from the first laminator roll (30a) is reduced to a third speed (V3) smaller than the second speed (V2), thereby allowing the second region (500b) of the metal layer (200) to pass between the first laminator roll (30a) and the second laminator roll (30b) by a machine direction length (MD2), while allowing the dry positive electrode film (100a) to pass by a length (MD2A) smaller than the machine direction length (MD2) of the second region (500b). Additionally, while passing the second region (500b) of the metal layer (200) between the first laminator roll (30a) and the second laminator roll (30b), the dry cathode active material layer (300a) is not laminated to the second region (500b) of the metal layer (200).

Referring to FIG. 1d, from the time point at which the first region (500a) adjacent to the second region (500b) of the metal layer (200) is introduced between the first laminator roll (30a) and the second laminator roll (30b), the supply speed of the dry positive electrode film (100a) from the first laminator roll (30a) onto the carbon layer (150a) of the first region (500a) of the metal layer (200) is increased again to a second speed (V2) greater than the third speed (V3), thereby laminating the dry positive electrode film (100a) on one surface of the metal layer (200) and disposing the dry positive electrode active material layer (300a) on one surface of the metal layer (200). The dry positive electrode film (30a) disposed between the first cutting line (CL1) and the second cutting line (CL2) can be easily separated from the surface of the first laminator roll (30a) by blocking a plurality of vacuum suction ports (45) disposed on the surface of the first laminator roll (30a) or by using a separate separation device (not shown) after passing between the first laminator roll (30a) and the second laminator roll (30b).

Referring to FIGS. 1A to 1D, this process is repeated simultaneously and sequentially for the other surface of the metal layer (200). In order to coat the dry positive electrode film (100b) on the other surface of the metal layer (200), the rotation speed of the 2-2 winding roll (20b) and the 2nd laminator roll (30b) is adjusted so that the dry positive electrode film (100b) is supplied from the 2-2 winding roll (20b) to the 2nd laminator roll (30b) at the first speed (V1). As a result, a dry electrode film (100, 100a, 100b) including a plurality of dry electrode active material layers (300, 300a, 300b) spaced at regular intervals can be easily manufactured.

In another embodiment, another dry electrode manufacturing device includes a first laminator roll and a second laminator roll arranged to be spaced apart from each other, at least one of the first laminator roll and the second laminator roll having a second rotational peripheral speed and being configured or driven to intermittently have a third rotational peripheral speed that is smaller than the second rotational peripheral speed, and the first laminator roll and the second laminator roll have opposite rotational directions.

Referring to FIGS. 1A to 1D, a dry electrode manufacturing device includes a first laminator roll (30a) and a second laminator roll (30b) which are arranged to be spaced apart from each other. At least one of the first laminator roll (30a) and the second laminator roll (30b) has a second rotational peripheral speed and is configured or driven to intermittently have a third rotational peripheral speed that is smaller than the second rotational peripheral speed. The first laminator roll (30a) and the second laminator roll (30b) have opposite rotational directions. Since the dry electrode manufacturing device has such a configuration, a dry electrode having a dry electrode active material layer of various patterns introduced on a metal layer can be easily manufactured.

Referring to FIGS. 1A to 1D, the dry electrode manufacturing device may further include a first winding roll (10). For example, a metal layer (200) is wound on the first winding roll (10).

A metal layer (100) can be provided between the first laminator roll (30a) and the second laminator roll (30b) from the first winding roll (10) at a first speed (V1).

A dry electrode film (100, 100a, 100b) is provided from at least one of a first laminator roll (30a) and a second laminator roll (30b) on a metal layer (200) at a second speed (V2), and can be intermittently provided at a third speed (V3) that is lower than the second speed (V2).

A dry electrode film (100, 100a, 100b) can be placed on a metal layer (200) while providing the dry electrode film (100, 100a, 100b) at a second speed (V2).

While providing the dry electrode film (100, 100a, 100b) at the third speed (V3), the dry electrode film (100, 100a, 100b) may be undisposed on the metal layer (200).

Referring to FIGS. 1A to 1D, in a dry electrode manufacturing device, the first laminator roll (30a) and the second laminator roll (30b) can manufacture a dry electrode (400) while having various rotational peripheral speeds (VRP).

Referring to FIGS. 1A and 1B, in a dry electrode manufacturing device, a metal layer (200) is provided between a first laminator roll (30a) and a second laminator roll (30b) at a first speed (V1) from a first winding roll (10) having a first rotational peripheral speed (VRP1). While the first region (500a) of the metal layer (200) and the dry electrode film (100, 100a, 100b) are simultaneously provided between the first laminator roll (30a) and the second laminator roll (30b), the first laminator roll (30a) and the second laminator roll (30b) may have a second rotational peripheral speed (VRP2). While the metal layer (200) is provided from the 2-1 winding roll (20a) at a first speed (V1) and the dry electrode film (100, 100a, 100b) is provided from the 2-2 winding roll (20b) at a second speed (V2), the metal layer (200) and the dry electrode film (100, 100a, 100b) pass between the first lamination roll (30a) and the second lamination roll (30b) having the second rotational peripheral speed (VRP2), so that the metal layer (200) and the dry electrode film (100, 100a, 100b) can be laminated with each other to form a dry electrode active material layer (300, 300a, 300b). The second rotational peripheral speed (VRP2) of the first lamination roll (30a) and the second lamination roll (30b) can be adjusted to have the same value as the first speed (V1) which is the provision speed of the metal layer (200) and/or the second speed (V2) which is the provision speed of the dry electrode film (100, 100a, 100b) at the point where the metal layer (200) and/or the dry electrode film (100, 100a, 100b) passing therebetween come into contact. The second rotational peripheral speed (VRP2) is, for example, the same value as the first speed (V1) and the second speed (V2).

Referring to FIG. 1c, in a dry electrode manufacturing device, while a second region (500b) of a metal layer (200) is provided between the first laminator roll (30a) and the second laminator roll (30b) and at least a part of a dry electrode film (100, 100a, 100b) is not provided between the first laminator roll (30a) and the second laminator roll (30b), at least one of the first laminator roll (30a) and the second laminator roll (30b) can be reduced to a third rotational peripheral speed (VRP3) lower than the second rotational peripheral speed (VRP2). For example, while the metal layer (200) is provided from the first winding roll (10) at a first speed (V1) and the dry electrode film (100a) is provided from the second-first winding roll (20a) at a third speed (V3) lower than the second speed (V2), the metal layer (200) may form a non-coated portion that does not include the dry electrode active material layer (300a) while passing between the first lamination roll (30a) and the second lamination roll (30b). For example, since the first lamination roll (30a) has a third rotational peripheral speed (VRP3) lower than the second rotational peripheral speed (VRP2), the dry electrode film (100a) may not be provided on the metal layer (200). The first laminator roll (30a) and the second laminator roll (30b) may have, for example, different rotational peripheral speeds (VRP). For example, the rotational peripheral speed ratio of the first laminator roll (30a) and the second laminator roll (30b) may be, for example, 9:1 to 1:9, 7:1 to 1:7, 5:1 to 1:5 or 5:2 to 2:5.

Alternatively, although not shown in the drawing, the positions of the first laminator roll (30a) and the second laminator roll (30b) may be further spaced from the metal layer (200), thereby forming a non-coated portion on the metal layer (200) without changing the rotational peripheral speed (VRP). When the positions of the first laminator roll (30a) and the second laminator roll (30b) are additionally spaced from the metal layer (200), the first laminator roll (30a) and the second laminator roll (30b) can maintain the second rotational peripheral speed (VRP2) even while the second region (500b) of the metal layer (200) is provided between the first laminator roll (30a) and the second laminator roll (30b) and the dry electrode film (100, 100a, 100b) is not provided between the first laminator roll (30a) and the second laminator roll (30b). For example, since the positions of the first laminator roll (30a) and the second laminator roll (30b) are spaced apart from the metal layer (200), the first laminator roll (30a) and the second laminator roll (30b) may not provide the dry electrode film (100, 100a, 100b) to the metal layer (200) while maintaining the second rotational peripheral speed (VRP2).

Referring to FIG. 1d, in a dry electrode manufacturing device, while the first region (500a) of the metal layer (200) and the dry electrode film (100, 100a, 100b) are simultaneously provided between the first laminator roll (30a) and the second laminator roll (30b), the rotational peripheral speed (VRP) of the first laminator roll (30a) and the second laminator roll (30b) is increased again from the third rotational peripheral speed (VRP3) to the second rotational peripheral speed (VRP2). Accordingly, while the metal layer (200) is provided from the 2-1 winding roll (20a) at a first speed (V1) and the dry electrode film (100, 100a, 100b) is provided from the 2-2 winding roll (20b) at a second speed (V2), the metal layer (200) and the dry electrode film (100, 100a, 100b) pass between the first lamination roll (30a) and the second lamination roll (30b) having the second rotational peripheral speed (VRP2), so that the metal layer (200) and the dry electrode film (100, 100a, 100b) can be laminated with each other to form a dry electrode active material layer (300, 300a, 300b).

In a dry electrode manufacturing device, the processes of FIGS. 1a to 1d are sequentially repeated to manufacture a dry electrode in which electrode active material layers (3000, 300a, 300b) are spaced apart and arranged on a metal layer (200).

The metal layer (200) used in the manufacture of a dry electrode is, for example, an electrode current collector.

The material constituting the electrode current collector may be any material that does not react with lithium, that is, does not form an alloy or compound with lithium, and is conductive. The electrode current collector is, for example, a metal or an alloy. The electrode current collector may be, for example, made of indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li), or an alloy thereof.

The electrode current collector may have a form selected from, for example, a sheet, a foil, a film, a plate, a porous body, a mesoporous body, a body containing through-holes, a polygonal ring body, a mesh body, a foam body, and a non-woven body, but is not necessarily limited to these forms, and any form used in the relevant technical field may be used.

The electrode current collector may have a reduced thickness compared to the electrode current collector included in a conventional electrode. Therefore, the electrode according to one embodiment is distinguished from the conventional electrode including a thick film current collector, for example, by including a thin film current collector. Since the electrode according to one embodiment employs a thin film current collector having a reduced thickness, the thickness of the electrode active material layer in the electrode including the thin film current collector is relatively increased. As a result, the energy density of a lithium battery employing such an electrode is increased. The thickness of the electrode current collector may be, for example, less than 15 um, 14.5 um or less, or 14 um or less. The thickness of the electrode current collector may be, for example, 0.1 um to less than 15 um, 1 um to 14.5 um, 2 um to 14 um, 3 um to 14 um, 5 um to 14 um, or 10 um to 14 um.

The electrode current collector has a reduced surface roughness compared to the electrode current collector included in the conventional electrode. Since the electrode current collector surface has a reduced surface roughness, the electrode current collector can form a uniform interface with the electrode active material layer and/or the intermediate layer (150, 150a, 150b). As a result, local side reactions and/or non-uniform electrode reactions at the interface between the electrode current collector and other layers are suppressed, and the cycle characteristics of a lithium battery including such an electrode are improved.

The maximum roughness depth (R _max ) of the electrode collector surface can be, for example, 3 um or less, 2 um or less, 1 um or less, 0.5 um or less, or 0.1 um or less. The maximum roughness depth (R _max ) of the electrode collector surface can be, for example, 10 nm to 3 um, 10 nm to 2 um, 10 nm to 1 um, 10 nm to 0.5 um, or 10 nm to 0.1 um.

The average roughness (R _a ) of the surface of the electrode collector can be, for example, 2 um or less, 1 um or less, 0.5 um or less, or 0.1 um or less. The average roughness (R _a ) of the surface of the electrode collector can be, for example, 10 nm to 2 um, 10 nm to 1 um, 10 nm to 0.5 um, or 10 nm to 0.1 um.

The root mean square (RMS) roughness (R _q ) of the electrode collector surface can be, for example, 2 μm or less, 1 μm or less, 0.5 μm or less, or 0.1 μm or less. The root mean square roughness (R _q ) of the electrode collector surface can be, for example, 10 nm to 2 μm, 10 nm to 1 μm, 10 nm to 0.5 μm, or 10 nm to 0.1 μm.

The electrode current collector may include, for example, a base film and a metal thin film layer disposed on one or both sides of the base film. The electrode current collector may include a substrate, and the substrate may have a structure including, for example, a base film and a metal thin film layer disposed on one or both sides of the base film. The intermediate layer (150, 150a, 150b) described above may be additionally disposed on the metal thin film layer. The base film may include, for example, a polymer. The polymer may be, for example, a thermoplastic polymer. The polymer may include, for example, polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polybutylene terephthalate (PBT), polyimide (PI), or a combination thereof. Since the base film includes a thermoplastic polymer, the base film may melt when a short circuit occurs, thereby suppressing a rapid increase in current. The base film may be, for example, an insulator. The metal film layer may include, for example, copper (Cu), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), or an alloy thereof. The metal film layer may act as an electrochemical fuse and may be cut off when overcurrent occurs to prevent a short circuit. The limit current and the maximum current may be controlled by controlling the thickness of the metal film layer. The metal film layer may be plated or deposited on the base film. When the thickness of the metal film layer decreases, the limit current and/or the maximum current of the electrode current collector decrease, so that the stability of the lithium battery in the event of a short circuit may be improved. A lead tab may be added to the metal film layer for connection to the outside. The lead tab may be welded to the metal film layer or the metal film layer/base film laminate by ultrasonic welding, laser welding, spot welding, or the like. When the base film and/or the metal film layer are melted during welding, the metal film layer may be electrically connected to the lead tab. In order to make the welding of the metal film layer and the lead tab more solid, a metal chip may be added between the metal film layer and the lead tab. The metal chip may be a metal chip made of the same material as the metal of the metal film layer. The metal chip may be, for example, a metal foil, a metal mesh, etc. The metal chip may be, for example, aluminum foil, copper foil, SUS foil, etc. By arranging the metal chip on the metal film layer and then welding it with the lead tab, the lead tab may be welded to the metal chip/metal film layer laminate or the metal chip/metal film layer/base film laminate. During welding, the base film, the metal film layer, and/or the metal chip may be melted, so that the metal film layer or the metal film layer/metal chip laminate may be electrically connected to the lead tab. The metal chip and/or the lead tab may be added to a portion of the metal film layer. The thickness of the base film can be, for example, 1 to 50 ㎛, 1.5 to 50 ㎛, 1.5 to 40 ㎛, or 1 to 30 ㎛. When the base film has a thickness in this range, the weight of the electrode assembly can be reduced more effectively. The melting point of the base film can be, for example, 100 to 300 ℃, 100 to 250 ℃ or less, or 100 to 200 ℃. When the base film has a melting point in this range, the base film can be melted during the process of welding the lead tab and easily bonded to the lead tab. In order to improve the adhesion between the base film and the metal film layer, a surface treatment such as corona treatment can be performed on the base film. The thickness of the metal film layer can be, for example, 0.01 to 3 ㎛, 0.1 to 3 ㎛, 0.1 to 2 ㎛, or 0.1 to ㎛. By having a thickness in this range of the metal film layer, the stability of the electrode assembly can be secured while maintaining conductivity. The thickness of the metal piece can be, for example, 2 to 10 ㎛, 2 to 7 ㎛, or 4 to 6 ㎛. By having a thickness in this range of the metal piece, the connection between the metal film layer and the lead tab can be performed more easily. By having the electrode current collector having this structure, the weight of the electrode can be reduced, and as a result, the energy density can be improved. The electrode current collector can be, for example, a positive electrode current collector. The electrode current collector can be, for example, a negative electrode current collector.

An interlayer (150, 150a, 150b) used in the manufacture of a dry electrode is, for example, arranged on at least one surface of a metal layer (200) to form a laminate.

A laminate further including a metal layer (200) and an intermediate layer (150, 150a, 150b) disposed on one surface of the metal layer (200) can be manufactured, for example, by the following method.

The material of the metal layer (200) refers to the electrode current collector part. The metal layer (200) used as the positive electrode current collector is, for example, aluminum foil. The metal layer (200) used as the negative electrode current collector is, for example, copper foil. The method of arranging one or more intermediate layers (150, 150a, 150b) on one side or both sides of the metal layer (200) is, for example, dry or wet arranging the intermediate layers (150, 150a, 150b) on one side or both sides of the metal layer (200). Wet coating coats, for example, a composition including a carbon-based conductive material and a binder on one side or both sides of the metal layer (200). The composition includes, for example, a carbon-based conductive material, a binder, and a process solvent. For the carbon-based conductive material and the binder, refer to the electrode part described above. The process solvent may be selected from solvents used in the preparation of an electrode slurry. The process solvent is removed by drying after the composition is coated on the metal layer (200). The coating method may be spin coating, dip coating, or the like, but is not limited thereto, and any coating method used in the relevant technical field may be used. Dry coating, for example, coats a carbon-based conductive material and/or a precursor thereof on one or both sides of the metal layer (200) by deposition, etc. The deposition is performed at a temperature of room temperature to high temperature and a pressure of normal pressure to vacuum. The intermediate layer (150, 150a, 150b) disposed by dry coating may not include a binder if it is made of a carbon-based material.

The thickness of the intermediate layer (150, 150a, 150b) is, for example, 30% or less, 25% or less, 20% or less, 15% or less, 10% or less, 5% or less, or 3% or less of the thickness of the metal layer (200). The thickness of the intermediate layer (150, 150a, 150b) is, for example, 0.01 to 30%, 0.1 to 30%, 0.5 to 30%, 1 to 25%, 1 to 20%, 1 to 15%, 1 to 10%, 1 to 5%, or 1 to 3% of the thickness of the metal layer (200). The thickness of the intermediate layer (150, 150a, 150b) is, for example, 10 nm to 5 ㎛, 50 nm to 5 ㎛, 200 nm to 4 ㎛, 500 nm to 3 ㎛, 500 nm to 2 ㎛, 500 nm to 1.5 ㎛, 700 nm to 1.3 ㎛. When the intermediate layer (150, 150a, 150b) has a thickness in this range, the bonding force between the metal layer (200) and the dry electrode film (100, 100a, 100b) or the metal layer (200) and the dry electrode active material layer is further improved, and an increase in the interfacial resistance is suppressed.

The intermediate layer (150, 150a, 150b) includes, for example, a binder. Since the intermediate layer (150, 150a, 150b) includes a binder, the bonding strength between the metal layer (200) and the dry electrode film (100, 100a, 100b) or the metal layer (200) and the dry electrode active material layer can be further improved. The binder included in the intermediate layer (150, 150a, 150b) is, for example, a conductive binder or a non-conductive binder. The conductive binder is, for example, an ion-conductive binder and/or an electron-conductive binder. A binder having both ion conductivity and electron conductivity can belong to both an ion-conductive binder and an electron-conductive binder.

Ion-conducting binders include, for example, polystyrene sulfonate (PSS), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), polyvinyl fluoride (PVF), polyvinylidene fluoride (PVDF), polymethyl methacrylate (PMMA), polyethylene oxide (PEO), polyethylene glycol (PEG), polyacrylonitrile (PAN), polytetrafluoroethylene (PTFE), polyacrylonitrile (PAN), polyaniline, and polyacetylene. Ion-conducting binders may include polar functional groups. Ion-conducting binders including polar functional groups include, for example, Nafion, Aquivion, Flemion, Gore, ACPLEX. (Aciplex), Morgane ADP, sulfonated poly(ether ether ketone), SPEEK, sulfonated poly(arylene ether ketone ketone sulfone), SPAEKKS, sulfonated poly(aryl ether ketone, SPAEK), poly[bis(benzimidazobenzisoquinolinones)], SPBIBI, poly(styrene sulfonate), PSS, lithium 9,10-diphenylanthracene-2-sulfonate, DPASLi ⁺ , etc. Electronically conductive binders include, for example, Examples of the conductive layer include polyacetylene, polythiophene, polypyrrole, poly(p-phenylene), poly(phenylenevinylene), poly(phenylenesulfide), polyaniline, etc. The intermediate layer (150, 150a, 150b) may be a conductive layer including, for example, a conductive polymer.

The binder included in the intermediate layers (150, 150a, 150b) can be selected from the binders included in the dry electrode films (100, 100a, 100b). The intermediate layers (150, 150a, 150b) can include the same binder as the dry electrode films (100, 100a, 100b). The binder included in the intermediate layers (150, 150a, 150b) is, for example, a fluorinated binder. The fluorinated binder included in the intermediate layers (150, 150a, 150b) is, for example, polyvinylidene fluoride (PVDF). The intermediate layers (150, 150a, 150b) are disposed on the metal layer (200) in a dry or wet manner, for example. The intermediate layer (150, 150a, 150b) may be a binding layer including, for example, a binder.

The intermediate layers (150, 150a, 150b) may further include, for example, a carbon-based conductive material. The carbon-based conductive material included in the intermediate layers (150, 150a, 150b) may be selected from the carbon-based conductive materials included in the dry electrode films (100, 100a, 100b). The intermediate layers (150, 150a, 150b) may include the same carbon-based conductive material as the electrode active material layer. Since the intermediate layers (150, 150a, 150b) include a carbon-based conductive material, the intermediate layers (150, 150a, 150b) may be, for example, conductive layers. The intermediate layers (150, 150a, 150b) may be, for example, conductive layers including a binder and a carbon-based conductive material.

The intermediate layers (150, 150a, 150b) can be disposed on the metal layer (200) in a wet manner, for example, by spin coating, dip coating, or the like. The intermediate layers (150, 150a, 150b) can be disposed on the metal layer (200) in a dry manner, for example, by deposition, such as CVD or PVD, by depositing a carbon-based conductive material on the metal layer (200) in a wet manner, for example, by spin coating, dip coating, or the like. The dry-coated intermediate layer (150, 150a, 150b) is made of a carbon-based conductive material and may not include a binder. The intermediate layer (150, 150a, 150b) may have a single-layer structure or a multi-layer structure including a plurality of layers.

The dry electrode film (100, 100a, 100b) used in the manufacture of the dry electrode is manufactured dry and therefore does not contain an intentionally added process solvent. The dry electrode film (100, 100a, 100b) does not contain, for example, a residual processing solvent. Although a trace amount of unintended solvent may remain in the dry electrode film (100, 100a, 100b), such solvent is not an intentionally added process solvent. Therefore, the dry electrode active material layer manufactured from the dry electrode film (100, 100a, 100b) is distinguished from a wet electrode active material layer manufactured by mixing an electrode component and a process solvent and then removing part or all of the process solvent by drying.

The dry electrode film (100, 100a, 100b) includes a dry electrode active material. The dry electrode active material is, for example, an electrode active material that is not impregnated, dissolved, or dispersed in a process solvent. The dry electrode active material is, for example, an electrode active material that includes a process solvent or does not come into contact with a process solvent. The dry electrode active material is, for example, an electrode active material that does not come into contact with a process solvent during the manufacturing process of the dry electrode film (100, 100a, 100b) and the dry electrode.

Dry electrode active materials are, for example, dry cathode active materials.

The cathode active material may be, for example, lithium metal oxide, and any material commonly used in the art may be used without limitation.

The cathode active material may be, for example, at least one of a composite oxide of lithium and a metal selected from cobalt, manganese, nickel, and combinations thereof, and specific examples thereof include Li _a A _1-b B' _b D ₂ (wherein 0.90 ≤ a ≤ 1, and 0 ≤ b ≤ 0.5); Li _a E _1-b B' _b O _2-c D _c (wherein 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05); LiE _2-b B' _b O _4-c D _c (wherein 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05); Li _a Ni _1-bc Co _b B' _c D _α (in the above formula, 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α <2); Li _a Ni _1-bc Co _b B' _c O _2-α F' _α (in the above formula, 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α <2); Li _a Ni _1-bc Co _b B' _c O _2-α F' _α (in the above formula, 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α <2); Li _a Ni _1-bc Mn _b B' _c D _α (in the above formula, 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α <2); Li _a Ni _1-bc Mn _b B' _c O _2-α F' _α (in the above formula, 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α <2); Li _a Ni _1-bc Mn _b B' _c O _2-α F' ₂ (in the above formula, 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α <2); Li _a Ni _b E _c G _d O ₂ (wherein 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0.001 ≤ d ≤ 0.1); Li _a Ni _b Co _c Mn _d G _e O ₂ (wherein 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0 ≤ d ≤ 0.5, 0.001 ≤ e ≤ 0.1); Li _a NiG _b O ₂ (wherein 0.90 ≤ a ≤ 1, 0.001 ≤ b ≤ 0.1); Li _a CoG _b O ₂ (wherein 0.90 ≤ a ≤ 1, 0.001 ≤ b ≤ 0.1); Li _a MnG _b O ₂ (wherein 0.90 ≤ a ≤ 1, 0.001 ≤ b ≤ 0.1); Li _a Mn ₂ G _b O ₄ (wherein 0.90 ≤ a ≤ 1, 0.001 ≤ b ≤ 0.1); QO ₂ ; QS ₂ ; LiQS ₂ ; V ₂ O ₅ ; LiV ₂ O ₅ ; LiI'O ₂ ; LiNiVO ₄ ; Li _(3-f) J ₂ (PO ₄ ) ₃ (0 ≤ f ≤ 2); Li _(3-f) Fe ₂ (PO ₄ ) ₃ (0 ≤ f ≤ 2); Any compound represented by the chemical formula LiFePO ₄ can be used:

In the chemical formula representing the compound described above, A is Ni, Co, Mn, or a combination thereof; B' is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof; D is O, F, S, P, or a combination thereof; E is Co, Mn, or a combination thereof; F' is F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; Q is Ti, Mo, Mn, or a combination thereof; I' is Cr, V, Fe, Sc, Y, or a combination thereof; J is V, Cr, Mn, Co, Ni, Cu, or a combination thereof.

It is also possible to use a compound having a coating layer added to the surface of the above-described compound, and it is also possible to use a mixture of the above-described compound and the compound having a coating layer added. The coating layer added to the surface of the above-described compound includes, for example, a coating element compound of an oxide, a hydroxide, an oxyhydroxide of the coating element, an oxycarbonate of the coating element, or a hydroxycarbonate of the coating element of the coating element. The compound forming the coating layer is amorphous or crystalline. The coating elements included in the coating layer are Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, or mixtures thereof. The method for forming the coating layer is selected within a range that does not adversely affect the properties of the positive electrode active material. The coating method is, for example, spray coating, dipping, etc. Since the specific coating method is well understood by those engaged in the relevant field, a detailed description thereof will be omitted.

The cathode active material is, for example, a composite cathode active material.

The composite cathode active material includes, for example, a core including a lithium transition metal oxide; and a shell disposed along a surface of the core, wherein the shell includes at least one first metal oxide represented by the chemical formula M _a O _b (0<a≤3, 0<b<4, when a is 1, 2, or 3, b is not an integer); and graphene, wherein the first metal oxide is disposed within a graphene matrix, wherein M is at least one metal selected from groups 2 to 13, 15, and 16 of the periodic table of elements, and the lithium transition metal oxide contains nickel, and the nickel content is 80 mol% or more with respect to the total mole number of transition metals. The shell including the first metal oxide and graphene is disposed on the core of the composite cathode active material.

Conventional graphene is difficult to uniformly coat on the core due to agglomeration. In contrast, the composite cathode active material uses a composite including a plurality of first metal oxides arranged in a graphene matrix, thereby preventing agglomeration of graphene and disposing a uniform shell on the core. Accordingly, contact between the core and the electrolyte is effectively blocked, thereby preventing side reactions due to contact between the core and the electrolyte. In addition, reduction of nickel ions (Ni ³⁺ -> Ni ²⁺ ) and cation mixing by the electrolyte are suppressed, thereby suppressing the generation of a resistance layer such as a NiO phase. In addition, dissolution of nickel ions is also suppressed. Since the shell including graphene is flexible, it easily accommodates changes in the volume of the composite cathode active material during charge and discharge, thereby suppressing the occurrence of cracks inside the composite cathode active material. Since graphene has high electronic conductivity, the interfacial resistance between the composite cathode active material and the electrolyte is reduced. Accordingly, the internal resistance of the lithium battery is maintained or reduced despite the introduction of the shell including graphene. In addition, since the first metal oxide has withstand voltage, deterioration of the lithium transition metal oxide included in the core can be prevented during charge/discharge at high voltage. As a result, the cycle characteristics and high-temperature stability of the lithium battery including the composite cathode active material are improved. The shell may include, for example, one kind of first metal oxide or two or more different first metal oxides. In addition, in the composite cathode active material, the lithium transition metal oxide has a high nickel content of 80 mol% or more with respect to the total mole number of transition metals, and can simultaneously provide high discharge capacity and cycle characteristics by disposing the shell including the first metal oxide and graphene on the core. Therefore, the composite cathode active material having a high nickel content of 80 mol% or more can provide improved capacity compared to a composite cathode active material having a relatively low nickel content, while still providing excellent life characteristics. The metal included in the first metal oxide may be, for example, one or more selected from Al, Nb, Mg, Sc, Ti, Zr, V, W, Mn, Fe, Co, Pd, Cu, Ag, Zn, Sb, and Se.

The first metal oxide may be, for example, at least one selected from Al ₂ O _z (0<z<3), NbO _x (0<x<2.5), MgO _x (0<x<1), Sc ₂ O _z (0<z<3), TiO _y (0<y<2), ZrO _y (0<y<2), V ₂ O _z (0<z<3), WO _y (0<y<2), MnO _y (0<y<2), Fe ₂ O _z (0<z<3), Co ₃ O _w (0<w<4), PdO _x (0<x<1), CuO _x (0<x<1), AgO _x (0<x<1), ZnO _x (0<x<1), Sb ₂ O _z (0<z<3), and SeO _y (0<y<2). By arranging the first metal oxide within the graphene matrix, the uniformity of the shell arranged on the core is improved, and the withstand voltage of the composite cathode active material is further improved. For example, the shell includes Al ₂ O _x (0<x<3) as the first metal oxide. The shell may further include at least one second metal oxide represented by the chemical formula M _a O _c (0<a≤3, 0<c≤4, when a is 1, 2, or 3, c is an integer). The M is at least one metal selected from groups 2 to 13, 15, and 16 of the periodic table of elements. For example, the second metal oxide includes the same metal as the first metal oxide, and the ratio of a and c, c/a, of the second metal oxide has a larger value than the ratio of a and b, b/a, of the first metal oxide. For example, c/a >b/a. The second metal oxide is selected from, for example, Al ₂ O ₃ , NbO, NbO ₂ , Nb ₂ O ₅ , MgO, Sc ₂ O ₃ , TiO ₂ , ZrO ₂ , V ₂ O ₃ , WO ₂ , MnO ₂ , Fe ₂ O ₃ , Co ₃ O ₄ , PdO, CuO, AgO, ZnO, Sb ₂ O ₃ , and SeO ₂ . The first metal oxide is a reduction product of the second metal oxide. The first metal oxide is obtained by reducing part or all of the second metal oxide. Therefore, the first metal oxide has a lower oxygen content and a higher oxidation number of the metal than the second metal oxide. For example, the shell includes the first metal oxide Al ₂ O _x (0<x<3) and the second metal oxide Al ₂ O ₃ . In the composite cathode active material, for example, the graphene included in the shell and the transition metal of the lithium transition metal oxide included in the core are chemically bound through a chemical bond. The carbon atom (C) of the graphene included in the shell and the transition metal (Me) of the lithium transition metal oxide are chemically bound through, for example, a CO-Me bond (for example, a CO-Ni bond) mediated by an oxygen atom. The core and the shell are composited by chemically bonding the graphene included in the shell and the lithium transition metal oxide included in the core. Therefore, it is distinguished from a simple physical mixture of graphene and lithium transition metal oxide. In addition, the first metal oxide included in the shell and the graphene are also chemically bound through a chemical bond. Here, the chemical bond is, for example, a covalent bond or an ionic bond. The covalent bond is, for example, a bond including at least one of an ester group, an ether group, a carbonyl group, an amide group, a carbonate anhydride group, and an acid anhydride group. The ionic bond is a bond including, for example, a carboxylic acid ion, an ammonium ion, an acyl cation group, etc. The thickness of the shell is, for example, 1 nm to 5 um, 1 nm to 1 um, 1 nm to 500 nm, 1 nm to 200 nm, 1 nm to 100 nm, 1 nm to 90 nm, 1 nm to 80 nm, 1 nm to 70 nm, 1 nm to 60 nm, 1 nm to 50 nm, 1 nm to 40 nm, 1 nm to 30 nm, 1 nm to 20 nm, or 1 nm to 10 nm. When the shell has a thickness in this range, an increase in the internal resistance of a lithium battery including the composite cathode active material is suppressed.

The content of the composite included in the composite cathode active material may be 3 wt% or less, 2 wt% or less, 1 wt% or less, 0.5 wt% or less, or 0.2 wt% or less based on the total weight of the composite cathode active material. The content of the composite may be 0.01 wt% to 3 wt%, 0.01 wt% to 1 wt%, 0.01 wt% to 0.7 wt%, 0.01 wt% to 0.6 wt%, 0.1 wt% to 0.5 wt%, 0.01 wt% to 0.2 wt%, 0.01 wt% to 0.1 wt%, or 0.03 wt% to 0.07 wt% based on the total weight of the composite cathode active material. When the composite cathode active material includes the composite in this range, the cycle characteristics of a lithium battery including the composite cathode active material are further improved. The average particle size of at least one selected from the first metal oxide and the second metal oxide included in the composite may be 1 nm to 1 um, 1 nm to 500 nm, 1 nm to 200 nm, 1 nm to 100 nm, 1 nm to 70 nm, 1 nm to 50 nm, 1 nm to 30 nm, 3 nm to 30 nm, 3 nm to 25 nm, 5 nm to 25 nm, 5 nm to 20 nm, or 7 nm to 20 nm. Since the first metal oxide and/or the second metal oxide has particle sizes in this nano-range, they can be more uniformly distributed within the graphene matrix of the composite. Accordingly, the composite can be uniformly coated on the core without agglomeration to form a shell. In addition, since the first metal oxide and/or the second metal oxide has particle sizes in this range, they can be more uniformly arranged on the core. Therefore, the withstand voltage characteristics can be more effectively exhibited by uniformly arranging the first metal oxide and/or the second metal oxide on the core. The average particle diameter of the first metal oxide and the second metal oxide is measured using, for example, a measuring device of a laser diffraction method or a dynamic light scattering method. The average particle diameter is measured using, for example, a laser scattering particle size distribution meter (for example, Horiba LA-920), and is the value of the median particle diameter (D50) when 50% is accumulated from the small particle side in volume conversion.

The core included in the composite cathode active material includes, for example, a lithium transition metal oxide represented by the following chemical formulas 1 to 8:

<Chemical formula 1>

Li _a Co _x M _y O _2-b A _b

In the above chemical formula 1,

1.0≤a≤1.2, 0≤b≤0.2, 0.9≤x≤1, 0≤y≤0.1, and x+y=1,

M is manganese (Mn), niobium (Nb), vanadium (V), magnesium (Mg), gallium (Ga), silicon (Si), tungsten (W), molybdenum (Mo), iron (Fe), chromium (Cr), copper (Cu), zinc (Zn), titanium (Ti), aluminum (Al), boron (B), or a combination thereof,

A is F, S, Cl, Br or a combination of these,

<Chemical formula 2>

Li _a Ni _x Co _y M _z O _2-b A _b

In the above chemical formula 2,

1.0≤a≤1.2, 0≤b≤0.2, 0.8≤x<1, 0≤y≤0.3, 0<z≤0.3, and x+y+z=1,

M is manganese (Mn), niobium (Nb), vanadium (V), magnesium (Mg), gallium (Ga), silicon (Si), tungsten (W), molybdenum (Mo), iron (Fe), chromium (Cr), copper (Cu), zinc (Zn), titanium (Ti), aluminum (Al), boron (B), or a combination thereof,

A is F, S, Cl, Br or a combination of these,

<Chemical Formula 3>

LiNi _x Co _y Mn _z O ₂

<Chemical Formula 4>

LiNi _x Co _y Al _z O ₂

In the above chemical formulas 3 and 4, 0.8≤x≤0.95, 0≤y≤0.2, 0<z≤0.2, and x+y+z=1.

<Chemical Formula 5>

LiNi _x Co _y Mn _z Al _w O ₂

In the above chemical formula 5, 0.8≤x≤0.95, 0≤y≤0.2, 0<z≤0.2, 0<w≤0.2, and x+y+z+w=1.

<Chemical Formula 6>

Li _a Ni _x Mn _y M' _z O _2-b A _b

In the above chemical formula 6,

1.0≤a≤1.2, 0≤b≤0.2, 0<x≤0.3, 0.5≤y<1, 0<z≤0.3, and x+y+z=1,

M' is cobalt (Co), niobium (Nb), vanadium (V), magnesium (Mg), gallium (Ga), silicon (Si), tungsten (W), molybdenum (Mo), iron (Fe), chromium (Cr), copper (Cu), zinc (Zn), titanium (Ti), aluminum (Al), boron (B), or a combination thereof,

A is F, S, Cl, Br or a combination of these,

<Chemical Formula 7>

Li _a M1 _x M2 _y PO _4-b X _b

In the above chemical formula 7, 0.90≤a≤1.1, 0≤x≤0.9, 0≤y≤0.5, 0.9<x+y<1.1, 0≤b≤2,

M1 is chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zirconium (Zr), or a combination thereof,

M2 is magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), titanium (Ti), zinc (Zn), boron (B), niobium (Nb), gallium (Ga), indium (In), molybdenum (Mo), tungsten (W), aluminum (Al), silicon (Si), chromium (Cr), vanadium (V), scandium (Sc), yttrium (Y) or a combination thereof, and X is O, F, S, P or a combination thereof.

<Chemical Formula 8>

Li _a M3 _z PO ₄

In the above chemical formula 8, 0.90≤a≤1.1, 0.9≤z≤1.1,

M3 is chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zirconium (Zr), or a combination thereof.

Dry electrode active materials are, for example, dry negative electrode active materials.

Any negative electrode active material that is used as a negative electrode active material of a lithium battery in the relevant technical field can be used. For example, it includes at least one selected from the group consisting of lithium metal, metals alloyable with lithium, transition metal oxides, non-transition metal oxides, and carbon-based materials. Metals alloyable with lithium include, for example, Si, Sn, Al, Ge, Pb, Bi, Sb Si-Y alloy (wherein Y is an alkali metal, an alkaline earth metal, a group 13 element, a group 14 element, a transition metal, a rare earth element, or a combination thereof, but not Si), Sn-Y alloy (wherein Y is an alkali metal, an alkaline earth metal, a group 13 element, a group 14 element, a transition metal, a rare earth element, or a combination thereof, but not Sn), etc. The element Y is, for example, Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Ti, Ge, P, As, Sb, Bi, S, Se, Te, Po, or a combination thereof. The transition metal oxide is, for example, lithium titanium oxide, vanadium oxide, lithium vanadium oxide, etc. The non-transition metal oxide is, for example, SnO ₂ , SiO _x (0<x<2), etc. The carbonaceous material is, for example, crystalline carbon, amorphous carbon, or a mixture thereof. The crystalline carbon is, for example, graphite, such as natural graphite or artificial graphite in the form of amorphous, platelet, flake, spherical, or fiber. Amorphous carbon includes, for example, soft carbon (low-temperature calcined carbon), hard carbon, mesophase pitch carbide, and calcined coke.

The dry electrode film (100, 100a, 100b) includes, for example, a dry binder. The dry binder is, for example, a binder that is not impregnated, dissolved, or dispersed in a process solvent. The dry binder is, for example, a binder that includes a process solvent or does not come into contact with a process solvent. The dry binder is, for example, a binder that does not come into contact with a process solvent during the manufacturing process of the dry electrode film (100, 100a, 100b) and the dry electrode. The dry binder is, for example, a fibrillized binder. The fibrillized binder can serve as a matrix that supports and binds the dry electrode active material and other components included in the dry electrode film (100, 100a, 100b). The fibrillized binder can be confirmed to have a fibrous form, for example, as shown in a scanning electron microscope image of a cross-section of an electrode. The fibrous binder has an aspect ratio of, for example, greater than 10, greater than 20, greater than 50, or greater than 100.

The dry binder may be, but is not limited to, any binder used in the manufacture of a dry electrode, such as, but not limited to, polytetrafluoroethylene (PTFE), polyvinylidene fluoride-hexapropylene (PVDF-HFP) copolymer, polyvinylidene fluoride (PVDF), polyvinyl alcohol, polyacrylonitrile, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, cellulose, polyvinyl pyrrolidone, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, styrene butadiene rubber (SBR), fluororubber, or copolymers thereof. The dry binder may particularly include a fluorinated binder. Fluorinated binders include, for example, polytetrafluoroethylene (PTFE), polyvinylidene fluoride-hexapropylene (PVDF-HFP) copolymer, or polyvinylidene fluoride (PVDF).

The content of the dry binder included in the dry electrode film (100, 100a, 100b) is, for example, 1 to 10 wt%, or 1 to 5 wt%, based on the total weight of the dry electrode film (100, 100a, 100b). When the dry electrode film (100, 100a, 100b) includes the dry binder in this range, the bonding strength of the dry electrode film (100, 100a, 100b) is improved, and the dry electrode produced can maintain a high energy density.

The dry electrode film (100, 100a, 100b) may further include, for example, a conductive material. The conductive material is, for example, a dry conductive material. The dry conductive material is, for example, a conductive material that is not impregnated, dissolved, or dispersed in a process solvent. The dry conductive material is, for example, a conductive material that includes a process solvent or does not come into contact with a process solvent. The dry conductive material includes, for example, a carbon-based conductive material. The carbon-based conductive material may be, but is not limited to, carbon black, graphite particles, natural graphite, artificial graphite, acetylene black, Ketjen black, carbon fibers; carbon nanotubes; and the like, and any material used as a carbon-based conductive material in the art may be used.

The content of the dry conductive material included in the dry electrode film (100, 100a, 100b) is, for example, 1 to 10 wt%, or 1 to 5 wt%, based on the total weight of the electrode active material layer. When the dry electrode film (100, 100a, 100b) includes the dry conductive material in this range, the conductivity of the dry electrode produced is improved, and the cycle characteristics of a lithium battery including the dry electrode can be improved.

Dry electrode films (100, 100a, 100b) can be manufactured, for example, by the following method.

First, a mixture is prepared by dry mixing a dry electrode active material, a dry conductive agent, and a dry binder.

Dry mixing means mixing without a process solvent. The process solvent is, for example, a solvent used in the manufacture of an electrode slurry. The process solvent is, for example, water, NMP, etc., but is not limited thereto, and is not limited as long as it is a process solvent used in the manufacture of an electrode slurry. Dry mixing can be performed using a stirrer at a temperature of 25° C. to 65° C. and a rotation speed of 10 to 10,000 rpm, or 100 to 10,000 rpm. Dry mixing can be performed using a stirrer for 1 to 200 minutes, or 1 to 150 minutes.

The dry mixing can be performed, for example, more than once. First, a first mixture can be prepared by first dry mixing a dry electrode active material, a dry conductive material, and a dry binder. The first dry mixing can be performed, for example, at a temperature of 25 to 65° C., at a rotation speed of 2000 rpm or less, for 15 minutes or less. The first dry mixing can be performed, for example, at a temperature of 25 to 65° C., at a rotation speed of 500 to 2000 rpm, for 5 to 15 minutes. The dry electrode active material, the dry conductive material, and the dry binder can be uniformly mixed by the first dry mixing. Subsequently, the dry electrode active material, the dry conductive material, and the dry binder can be dry mixed a second time to prepare a second mixture. The secondary dry mixing can be performed, for example, at a temperature of 25 to 65 °C, at a rotation speed of 4000 rpm or more, for a time of 10 minutes or more. The secondary dry mixing can be performed, for example, at a temperature of 25 to 65 °C, at a rotation speed of 4000 to 9000 rpm, for a time of 10 to 60 minutes. By the secondary dry mixing, a dry mixture comprising a fibrillated dry binder can be obtained.

The stirrer is, for example, a kneader. The stirrer includes, for example, a chamber; one or more rotating shafts arranged inside the chamber and rotating; and blades rotatably coupled to the rotating shaft and arranged in the longitudinal direction of the rotating shaft. The blades may be, for example, one or more blades selected from a ribbon blade, a sigma blade, a jet (Z) blade, a dispersion blade, and a screw blade. By including the blades, the electrode active material, the dry conductive material, and the dry binder can be effectively mixed without a solvent to produce a dough-like mixture. The produced mixture can be fed into an extrusion device and extruded in a sheet form. The pressure during extrusion is, for example, 4 MPa to 100 MPa, or 10 MPa to 90 MPa. The obtained mixture can be in the form of a film. That is, the obtained mixture can be a dry electrode film (100, 100a, 100b).

As the dry conductive agent, carbon black, graphite particles, natural graphite, artificial graphite, acetylene black, Ketjen black, carbon fibers; carbon nanotubes; metal powders or metal fibers or metal tubes such as copper, nickel, aluminum, and silver; conductive polymers such as polyphenylene derivatives, etc. are used, but are not limited thereto, and any conductive agent used in the relevant technical field may be used. The conductive agent is, for example, a carbon-based conductive agent.

Examples of dry binders include vinylidene fluoride/hexafluoropropylene copolymer, polyvinylidene fluoride, polyacrylonitrile, polymethyl methacrylate, polytetrafluoroethylene (PTFE), mixtures of the above polymers, styrene butadiene rubber-based polymers, etc., and examples of solvents include, but are not limited to, N-methylpyrrolidone (NMP), acetone, water, etc., and any solvent used in the relevant technical field may be used.

It is also possible to form pores inside the electrode plate by further adding a plasticizer or a pore forming agent to the electrode active material composition.

The contents of electrode active material, dry conductive agent, and dry binder used in the electrode active material layer are at levels typically used in lithium batteries.

The positive electrode uses a positive electrode active material as an electrode active material. The positive electrode active material refers to the electrode section described above. The negative electrode uses a negative electrode active material as an electrode active material. The negative electrode active material refers to the electrode section described above.

In a dry electrode manufactured by a dry electrode manufacturing method according to an embodiment of the present invention, a dry electrode active material layer has a change rate in a vertical relative binding force (F VR) according to a depth from a first point spaced 5% apart from the surface of the dry electrode active material layer in the direction of the electrode current collector to a second point spaced 5% apart from the surface of the electrode current collector, based on the total thickness of the dry electrode active material layer, when measured by a _SAICAS (surface and Interfacial Measuring Analysis System).

The rate of change in vertical relative bonding force is calculated from the following mathematical expression 1. For the SAICAS measurement method, see Evaluation Example 1, for example.

<Mathematical formula 1>

Rate of change of vertical relative binding force (F _V ) = [(maximum vertical relative binding force - minimum vertical relative binding force) / minimum vertical relative binding force)] × 100

In a dry electrode, since the rate of change in the vertical relative adhesion force of the dry electrode active material layer is 300% or less when measured by a surface and interfacial measuring analysis system (SAICAS), the uniformity of distribution of components of the dry electrode active material layer within the dry electrode is improved. In addition, since side reactions and increases in internal resistance due to uneven distribution of components within the dry electrode active material layer are suppressed, the reversibility of the electrode reaction can be improved. Therefore, even in the case of a dry electrode having a high loading, the cycle characteristics of a lithium battery are improved. The rate of change in the vertical relative adhesion force of the dry electrode active material layer is, for example, 10 to 300%, 20 to 250%, 30 to 200%, 40 to 160%, 50 to 150%, or 60 to 140%.

In a dry electrode manufactured by a dry electrode manufacturing method according to an embodiment of the present invention, the dry electrode active material layer has, when measured by SAICAS, a ratio of a horizontal binding force of a second horizontal binding force (F _HA2 ) at a second point located 10% away from the surface of the electrode collector to a first horizontal binding force (F _HA1 ) at a first point located 10% away from the surface of the dry electrode active material layer in the direction of the electrode current collector is 50% or more.

The horizontal bonding force ratio is expressed, for example, by the following mathematical expression 2.

<Mathematical formula 2>

Horizontal bonding force ratio = [Second horizontal bonding force (F _H2 ) / First horizontal bonding force (F _H1 )] × 100

In a dry electrode, when the horizontal binding force ratio is 50% or more in the SAICAS measurement, the uniformity of the distribution of components within the electrode is further improved. When the electrode has a horizontal binding force ratio in this range, the cycle characteristics of a lithium battery employing the electrode are further improved. The horizontal binding force ratio is, for example, 50 to 300%, 50 to 250%, 50 to 200%, 50 to 150%, or 50 to 100%.

According to another embodiment, a dry electrode (400) is provided. The dry electrode (400) is manufactured, for example, by the method described above.

According to another embodiment, a dry electrode includes a metal layer (200); and dry electrode active material layers spaced apart from each other on one or both surfaces of the metal layer (200). A non-coated region in which the metal layer (200) is exposed is disposed between the dry electrode active material layers spaced apart from each other. The dry electrode active material layer may have, for example, anisotropic tensile strength. Since the dry electrode is disposed adjacent to one side of the dry electrode active material layer and has a surface of the metal layer (200) that is not covered by the dry electrode active material layer free of burrs or depressions, side reactions and/or deterioration caused by burrs and/or depressions during a charge/discharge process are suppressed, and thus the cycle characteristics of a lithium battery including the dry electrode are improved.

The dry electrode includes, for example, a metal layer (200); an intermediate layer (150, 150a, 150b) spaced apart from each other on one or both surfaces of the metal layer (200); and a dry electrode active material layer arranged on the intermediate layer (150, 150a, 150b). The dry electrode active material layer directly arranged on the electrode current collector is free. An uncoated portion where the metal layer (200) is exposed is arranged between the dry electrode active material layers arranged spaced apart from each other. The dry electrode active material layer may have, for example, anisotropic tensile strength. A burr or depression is free on one surface of the electrode current collector that is arranged adjacent to one side of the dry electrode active material layer and is not covered by the intermediate layer (150, 150a, 150b). For specific details on the electrode current collector, the intermediate layer (150, 150a, 150b) and the dry electrode active material layer, refer to the dry electrode manufacturing method described above. The dry electrode active material layer has substantially the same components and/or physical properties as the dry electrode film (100, 100a, 100b). The dry electrode is, for example, a dry positive electrode and/or a dry negative electrode.

A lithium battery (1) according to another embodiment includes the above-described dry electrode.

According to another embodiment, a lithium battery (1) includes a cathode; an anode; and an electrolyte disposed between the cathode and the anode, wherein at least one of the cathode and the anode is formed by a dry electrode manufactured by the above-described dry electrode manufacturing method or by cutting the same.

Lithium batteries (1) include, for example, lithium ion batteries, lithium solid-state batteries, and lithium air batteries.

The lithium battery (1) is manufactured by, for example, the following exemplary method, but is not necessarily limited to this method and varies depending on required conditions.

First, one or both of the positive electrode and the negative electrode can be manufactured according to the above-described dry electrode manufacturing method. Alternatively, when one of the positive electrode and the negative electrode is manufactured by the above-described electrode manufacturing method, the other electrode can be manufactured by a wet manufacturing method. For example, the other electrode can be manufactured by manufacturing an electrode slurry including an electrode active material, a conductive material, a binder, and a solvent, coating the manufactured electrode slurry on an electrode current collector, and drying it. The conductive material and binder included in the electrode manufactured by the wet method can be selected from the conductive material and binder used in the manufacture of the above-described dry electrode.

Next, a separator to be inserted between the positive and negative electrodes is prepared.

Any separator that is commonly used in lithium batteries can be used. For example, a separator having low resistance to ion movement of the electrolyte and excellent electrolyte moisture retention ability is used. The separator is selected from, for example, glass fiber, polyester, Teflon, polyethylene, polypropylene, polytetrafluoroethylene (PTFE), or a combination thereof, and is in the form of a nonwoven fabric or a woven fabric. For lithium ion batteries, a windable separator such as polyethylene or polypropylene is used, and for lithium ion polymer batteries, a separator having excellent organic electrolyte moisture retention ability is used.

The separator is manufactured by the following exemplary methods, but is not necessarily limited to these methods and may be adjusted according to required conditions.

First, a separator composition is prepared by mixing a polymer resin, a filler, and a solvent. The separator composition is directly coated on the top of the electrode and dried to form a separator. Alternatively, the separator composition is cast on a support and dried, and then a separator film peeled from the support is laminated on the top of the electrode to form a separator.

The polymer used in the manufacture of the separator is not particularly limited, and any polymer used as a binder for the electrode plates may be used. For example, vinylidene fluoride/hexafluoropropylene copolymer, polyvinylidene fluoride (PVDF), polyacrylonitrile, polymethyl methacrylate, or mixtures thereof may be used.

Next, the electrolyte is prepared.

The electrolyte is, for example, an organic electrolyte. An organic electrolyte is prepared by dissolving a lithium salt in an organic solvent, for example.

Any organic solvent used in the art may be used. Examples of the organic solvent include propylene carbonate, ethylene carbonate, fluoroethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, methyl isopropyl carbonate, dipropyl carbonate, dibutyl carbonate, benzonitrile, acetonitrile, tetrahydrofuran, 2-methyltetrahydrofuran, γ-butyrolactone, dioxolane, 4-methyldioxolane, N,N-dimethylformamide, dimethylacetamide, dimethyl sulfoxide, dioxane, 1,2-dimethoxyethane, sulfolane, dichloroethane, chlorobenzene, nitrobenzene, diethylene glycol, dimethyl ether, or mixtures thereof.

Any lithium salt used in the relevant technical field is also possible. Lithium salts include, for example, LiPF ₆ , LiBF ₄ , LiSbF ₆ , LiAsF ₆ , LiClO ₄ , LiCF ₃ SO ₃ , Li(CF ₃ SO ₂ ) ₂ N, LiC ₄ F ₉ SO ₃ , LiAlO ₂ , LiAlCl ₄ , LiN(C _x F _2x+1 SO ₂ )(C _y F _2y+1 SO ₂ ) (where x and y are natural numbers), LiCl, LiI or mixtures thereof.

Alternatively, the electrolyte is a solid electrolyte. The solid electrolyte may be, for example, boron oxide, lithium oxynitride, or the like, but is not limited thereto, and any solid electrolyte used in the relevant technical field may be used. The solid electrolyte may be formed on the cathode by, for example, sputtering or a separate solid electrolyte sheet may be laminated on the cathode. The solid electrolyte may be, for example, an oxide-based solid electrolyte or a sulfide-based solid electrolyte.

Referring to FIG. 3, a lithium battery (1) according to an embodiment includes a positive electrode (3), a negative electrode (2), and a separator (4). The positive electrode (3), the negative electrode (2), and the separator (4) are wound or folded to form a battery structure (7). The formed battery structure (7) is accommodated in a battery case (5). An organic electrolyte is injected into the battery case (5) and sealed with a cap assembly (6), thereby completing the lithium battery (1). The battery case (5) is cylindrical, but is not necessarily limited to this shape, and may be, for example, square, thin-film, etc.

Referring to FIG. 4, a lithium battery (1a) according to one embodiment includes a positive electrode (3a), a negative electrode (2a), and a separator (4a). A separator (4a) is arranged between the positive electrode (3a) and the negative electrode (2a), and the positive electrode (3a), the negative electrode (2a), and the separator (4a) are wound or folded to form a battery structure (7a). The formed battery structure (7a) is accommodated in a battery case (5a). An electrode tab (8a) that acts as an electrical path for inducing current formed in the battery structure (7a) to the outside may be included. An organic electrolyte is injected into the battery case (5a) and sealed to complete the lithium battery (1a). The battery case (5a) is square, but is not necessarily limited to this shape, and may be, for example, cylindrical, thin-film, etc.

Referring to FIG. 5, a lithium battery (1b) according to an embodiment includes a positive electrode (3b), a negative electrode (2b), and a separator (4b). A separator (4b) is arranged between the positive electrode (3b) and the negative electrode (2b), thereby forming a battery structure. A battery structure (7b) is stacked in a bi-cell structure and then accommodated in a battery case (5b). An electrode tab (8b) that acts as an electrical path for guiding a current formed in the battery structure (7b) to the outside may be included. An organic electrolyte is injected into the battery case (5b) and sealed, thereby completing the lithium battery (1b). The battery case (5b) is square, but is not necessarily limited to this shape, and may be, for example, cylindrical, thin-film, etc.

The pouch-type lithium battery corresponds to each of the lithium batteries of FIGS. 3 to 5 in which a pouch is used as a battery case. The pouch-type lithium battery includes one or more battery structures. A separator is arranged between a positive electrode and a negative electrode to form a battery structure. The battery structures are laminated in a bi-cell structure, then impregnated with an organic electrolyte, and accommodated and sealed in a pouch to complete the pouch-type lithium battery. For example, although not shown in the drawings, the above-described positive electrode, negative electrode, and separator may be simply laminated and accommodated in a pouch in the form of an electrode assembly, or may be wound or folded into a jellyroll-type electrode assembly and then accommodated in a pouch. Subsequently, an organic electrolyte is injected into the pouch and sealed to complete the lithium battery.

Lithium batteries have excellent life characteristics and high-rate characteristics, so they are used in electric vehicles (EVs). For example, they are used in hybrid vehicles such as plug-in hybrid electric vehicles (PHEVs). They are also used in fields that require large amounts of power storage. For example, they are used in electric bicycles, power tools, etc.

A plurality of lithium batteries are stacked to form a battery module, and the plurality of battery modules form a battery pack. This battery pack can be used in all devices requiring high capacity and high output. For example, it can be used in laptops, smartphones, electric vehicles, etc. The battery module includes, for example, a plurality of batteries and a frame that holds them. The battery pack includes, for example, a plurality of battery modules and a bus bar that connects them. The battery module and/or the battery pack may further include a cooling device. The plurality of battery packs are controlled by a battery management system. The battery management system includes a battery pack and a battery control device connected to the battery pack.

The present invention is described in more detail through the following examples and comparative examples. However, the examples are intended to illustrate the present invention and the scope of the present invention is not limited to these examples.

(Manufacture of lithium batteries (half-cell))

Example 1: Dry electrode film, 1st speed: 2nd speed = 100: 50

(metal layer)

Referring to FIGS. 1a to 1d, an aluminum thin film (200) wound on a first winding roll (10) was prepared. The thickness of the aluminum thin film was 12 ㎛.

An aluminum film is supplied from a first winding roll (10) between a first laminator roll (30a) and a second laminator roll (30b) at a first speed (V1), passes between the first laminator roll (30a) and the second laminator roll (30b), and is then wound again on a third winding roll (not shown).

Before the aluminum film (200) is supplied between the first laminator roll and the second laminator roll, a carbon layer is repeatedly placed as an interlayer in the length direction of the aluminum film on one side of the aluminum film while maintaining a constant interval.

The region where a plurality of carbon layers (150, 150a, 150b) are arranged spaced apart from each other on the aluminum thin film (200) is the first region (500a), and the region where the carbon layers (150, 150a, 150b) are not arranged and the aluminum thin film is exposed is the second region (500b).

The ratio of the length (L1) of the first region (500a) and the length (L2) of the second region (500b) in the longitudinal direction of the aluminum film (200) was 50:1. The ratio of the width (W1) of the aluminum film (200) and the length (L1) of the second region in the longitudinal direction of the aluminum film (200) was 5:1.

The carbon layers (150, 150a, 150b) were formed by coating a composition including a carbon conductive material (Danka black) and polyvinylidene fluoride (PVDF) on an aluminum thin film (100) and then drying the coating. The thickness of the carbon layers (150, 150a, 150b) formed on one surface of the aluminum thin film (100) was approximately 1 ㎛.

(dry electrode film)

LiNi _0.91 Co _0.05 Al _0.04 O ₂ (hereinafter referred to as NCA91) having an average particle size (D50) of 15 ㎛ as a dry cathode active material, carbon conductive material (Denka Black) as a dry conductive material, and polytetrafluoroethylene (PTFE) as a dry binder were placed in a blade mixer at a weight ratio of 96:1.8:2.2, and then primary dry mixing was performed at a speed of 1000 rpm at 25°C for 10 minutes to prepare a first dry mixture in which the cathode active material, conductive material, and binder were uniformly mixed.

Subsequently, in order to allow the fibrillization of the dry binder to proceed, the first mixture was additionally mixed at 25°C and a speed of 5000 rpm for 20 minutes to prepare a second dry mixture. No separate solvent was used in the preparation of the first mixture and the second mixture. The prepared second mixture was put into an extruder and extruded to prepare a dry positive electrode film. The pressure during extrusion was approximately 50 MPa. The prepared dry positive electrode film is a self-standing film.

The prepared dry positive electrode film was wound onto the 2-1 winding roll (20a) and the 2-2 winding roll (20b), respectively.

(dry electrode)

Referring to FIGS. 1a to 1d, the rotation speeds of the first take-up roll (10) and the third take-up roll (not shown) were adjusted so that the aluminum film (200) was supplied between the first laminator roll (30a) and the second laminator roll (30b) at a first speed (V1).

The rotation speeds of the 2-1 winding roll (20a) and the first laminator roll (30a) were adjusted so that the dry cathode film (100a) was supplied from the 2-1 winding roll (20a) to the first laminator roll (30a) on the aluminum thin film (200) at the first speed (V1).

The dry positive electrode film (100a) was maintained attached to the surface of the first laminator roll (30a) by a plurality of vacuum suction holes (45) arranged on the surface of the first laminator roll (30a).

FIG. 1e is a plan view of an aluminum thin film (200) used in Example 1, in which a carbon layer (150a) is intermittently coated on a first region (500a) on one surface of the aluminum thin film (200). Although not shown in the drawing, a carbon layer (150a) is intermittently coated on a first region (500a) on the other surface of the aluminum thin film (200).

First, referring to FIG. 1a, while passing the first region (500a) of the aluminum thin film (200) between the first laminator roll (30a) and the second laminator roll (30b), the dry positive electrode film (100a) is supplied from the first laminator roll (30a) at a second speed (V2) onto the carbon layer (150a) of the first region (500a) of the aluminum thin film (200), thereby laminating the dry positive electrode film (100a) on one surface of the aluminum thin film (200) and disposing the dry positive electrode active material layer (300a) on one surface of the electrode current collector (200).

The second speed (V2) for supplying the dry anode film (100a) was the same as the first speed (V1) for supplying the aluminum thin film (200).

Before supplying the second region (500b) adjacent to the first region (500a) of the aluminum film (200) between the first laminator roll (30a) and the second laminator roll (30b), a dry positive electrode film (100a) corresponding to the machine direction length (MD1) of the second region (500b) of the aluminum film (200) is attached to the surface of the first laminator roll (30a), and a first cutting line (CL1) and a second cutting line (CL2) are simultaneously introduced into the dry positive electrode film (100a) by a pair of knives (50, 50a, 50b) spaced apart by a length (MD2A) corresponding to 50% of the machine direction length (MD1) of the second region (500b).

Subsequently, while the second region of the aluminum film passes between the first laminator roll and the second laminator roll, the dry positive electrode film supplied from the first roll is cut by slowing down the dry positive electrode film at a second speed (V2) which is 50% of the first speed (V1), thereby delaying the supply of the dry positive electrode film so that a dry positive electrode active material layer is not formed in the second region of the aluminum film.

Then, while the first region of the aluminum film passes between the first laminator roll and the second laminator roll, the speed of the dry positive electrode film from the first roll is increased again to the first speed (V1) and supplied onto the carbon layer of the first region of the aluminum film, and the dry positive electrode film is laminated onto one surface of the aluminum film, and a dry positive electrode active material layer (300a) is disposed on one surface of the electrode current collector (200). The dry positive electrode film (30a) disposed between the first cutting line (CL1) and the second cutting line (CL2) can be easily separated from the surface of the first laminator roll (30a) after passing between the first laminator roll (30a) and the second laminator roll (30b) by blocking a plurality of vacuum intake ports (45) disposed on the surface of the first laminator roll (30a) or by using a separate separation device (not shown).

The above-described process was sequentially repeated for the first region (500a) and the second region (500b) of one side of the aluminum thin film (200) to intermittently place an electric electrode active material layer (300a) on the aluminum thin film (200).

Referring to FIGS. 1A to 1D, this process was repeated simultaneously and sequentially for the other surface of the aluminum thin film (200). In order to coat the other surface of the aluminum thin film (200) with a dry positive electrode film (100b), the rotation speeds of the 2-2 winding roll (20b) and the 2nd laminator roll (30b) were adjusted so that the dry positive electrode film (100b) was supplied from the 2-2 winding roll (20b) to the 2nd laminator roll (30b) at the first speed (V1).

In this way, a dry positive electrode was manufactured in which a dry positive electrode active material layer was intermittently laminated on an aluminum thin film by sequentially supplying the first region and the second region of the aluminum thin film from the first roll while disposing the dry positive electrode film on the first region in the manner described above and not disposing the dry positive electrode film on the second region.

Figure 1f is a plan view of a dry electrode (400) manufactured in Example 1, in which a cathode carbon layer (150a) is intermittently laminated on a first region (500a) on one side of an aluminum thin film (200). (Manufacturing of a coin cell)

A coin cell was manufactured by cutting the second region of the dry positive electrode manufactured as described above and using it as a positive electrode, lithium metal as a counter electrode, a PTFE separator, and a solution of 1.3 M LiPF ₆ dissolved in EC (ethylene carbonate) + EMC (ethyl methyl carbonate) + DMC (dimethyl carbonate) (3:4:3 by volume) as an electrolyte. Since the second region was cut at a point spaced a certain distance from the dry positive electrode active material layer, there was no formation of burrs and/or depressions around the dry positive electrode active material layer.

Example 2: Dry electrode film, first speed: second speed = 100: 70

A dry electrode and a lithium battery were manufactured in the same manner as in Example 1, except that the second speed (V2) was changed to 70% of the first speed (V1) and the distance between a pair of knives (50a) was changed to 70% of the second region distance.

Example 3: Dry electrode film, 1st speed: 2nd speed = 100: 30

A dry electrode and a lithium battery were manufactured in the same manner as in Example 1, except that the second speed (V2) was changed to 30% of the first speed (V1) and the distance between a pair of knives (50a) was changed to 30% of the second region distance.

Example 4: Dry electrode film, 1st speed: 2nd speed = 100: 0

A dry electrode and a lithium battery were manufactured in the same manner as in Example 1, except that the second speed (V2) was changed to 0% of the first speed (V1) and the distance between a pair of knives (50a) was changed to 0.

Comparative Example 1: Dry Electrode Film, 1st Speed: 2nd Speed = 100:100

A dry electrode and a lithium battery were manufactured in the same manner as in Example 1, except that the second speed (V2) was maintained the same as the first speed (V1) and the use of a knife (50a) was excluded.

Since the first velocity (V1) and the second velocity (V2) are the same, the dry electrode film was placed on both the first region and the second region of the electrode collector.

A dry electrode film was removed from the second region using a laser cutter along the boundary between the first region and the second region, and a dry cathode was manufactured in which a dry cathode active material layer was disposed only on the first region.

During the process of removing the second region of the dry electrode film, the surface of the positive electrode collector was damaged by the laser. Burrs and/or depressions were formed on the positive electrode collector adjacent to the cut portion of the manufactured dry positive electrode active material layer.

Comparative Example 2: Dry Powder

(dry electrode film)

LiNi _0.91 Co _0.05 Al _0.04 O ₂ (hereinafter referred to as NCA91) having an average particle size (D50) of 15 ㎛ as a dry cathode active material, carbon conductive material (Denka Black) as a dry conductive material, and polytetrafluoroethylene (PTFE) as a dry binder were placed in a blade mixer at a weight ratio of 96:1.8:2.2, and then primary dry mixing was performed at a speed of 1000 rpm at 25°C for 10 minutes to prepare a first dry mixture in which the cathode active material, conductive material, and binder were uniformly mixed.

(metal layer)

A metal layer was prepared in the same manner as in Example 1, except that the carbon layer was placed only on one side of the aluminum foil.

(dry electrode)

First speed (V1) First speed (V1) Except that the first dry mixture manufactured above was supplied between the aluminum thin film (200) and the first laminator roll (30a) or the second laminator roll (30b) instead of the dry cathode film (100a), and the speed of the first laminator roll (30a) or the second laminator roll (30b) was kept constant, a dry electrode film (100) was manufactured in the same manner as in Example 1.

Referring to FIG. 2, a first dry mixture (60) and an aluminum thin film (200) were simultaneously passed between a first laminator roll (30a) and a second laminator roll (30b) to laminate them, thereby forming a dry positive electrode active material layer (300a) on one surface of an electrode current collector (200).

While the first dry mixture passed through the first laminator roll (30a) and the second laminator roll (30b), fibrillization of the dry binder progressed, and a dry positive electrode active material layer (300a) was formed on one surface of the electrode current collector (200).

A dry positive electrode active material layer (300a) was formed in both the first region (500a) of the electrode current collector (200) including the carbon layer (150a) and the second region (500b) of the electrode current collector not including the carbon layer (150a). The dry positive electrode active material layer (300a) disposed in the second region (500b) of the electrode current collector (200) was selectively removed to manufacture a dry positive electrode (400).

A dry cathode film (100a) was selectively removed from the second region (500b) using a laser cutter along the boundary between the first region (500a) and the second region (500b), and a dry cathode was manufactured in which a dry cathode active material layer (300a) was disposed only on the first region (500a).

Although not shown in the drawing, the surface of the positive electrode collector was damaged by the laser during the process of removing the second region of the dry electrode film. A burr and/or a depression adjacent to the cut portion of the manufactured dry positive electrode active material layer was formed on the positive electrode collector. Cracks occurred on the surface of the dry positive electrode active material layer included in the dry positive electrode. It was determined that the cracks occurred in the dry positive electrode active material layer manufactured by applying high pressure to fiberize the dry binder during the dry positive electrode manufacturing process.

(Manufacturing of coin cells)

A coin cell was manufactured by cutting a part of the dry positive electrode manufactured above, using the positive electrode, lithium metal as a counter electrode, a PTFE separator, and a solution of 1.3 M LiPF ₆ dissolved in EC (ethylene carbonate) + EMC (ethyl methyl carbonate) + DMC (dimethyl carbonate) (volume ratio of 3:4:3) as an electrolyte.

Comparative Example 3: Wet Anode

(Manufacture of wet anode)

A mixture of LiNi _0.91 Co _0.05 Al _0.04 O ₂ (hereinafter referred to as NCA91) having an average particle size (D50) of 15 ㎛ as a cathode active material, a carbon conductive material (Denka Black) as a conductive material, and polytetrafluoroethylene (PTFE) as a binder was mixed in a weight ratio of 96:1.8:2.2 together with N-methylpyrrolidone (NMP) in an agate mortar to prepare a slurry for forming a cathode active material layer. The slurry was bar coated on one side of a 12 ㎛ thick aluminum foil cathode current collector, dried at room temperature, and then dried again under vacuum at 120° C. to introduce a cathode active material layer, thereby preparing a laminate. The prepared laminate was rolled to manufacture a cathode. The pressure during rolling was 3.0 ton/cm. The thickness of the cathode active material layer of the cathode of Comparative Example 1 was the same as the thickness of the cathode active material layer of the cathode of Example 1.

Reference Example 1: Dry anode without interlayer

A dry positive electrode was manufactured in the same manner as in Example 1, except that a 12 μm thick aluminum film without a carbon layer as an interlayer was used as a positive electrode current collector.

The dry cathode active material layer was partially peeled off from the aluminum foil.

(Manufacturing of coin cells)

Because the dry cathode active material layer was partially peeled off from the cathode current collector, it was impossible to manufacture a coin cell.

Evaluation Example 1: Evaluation of vertical bonding strength of the cathode active material layer (I)

Using SAICAS (SAICAS EN-EX, Daipla Wintes, JAPAN), the bonding characteristics of the cathode active material layer included in the dry cathode of Example 1 and the wet cathode manufactured in Comparative Example 3 were analyzed.

Using a diamond blade with a width of 1 mm, constant velocity analysis was performed under the conditions of a clearance angle of 10°, a rake angle of 20°, a shearing angle of 45°, a horizontal velocity of 4 ㎛/s, and a vertical velocity of 0.4 ㎛/s to measure the vertical force (F _V ) according to depth.

First, a first constant velocity analysis was performed from the first position on the surface of the positive electrode active material layer to the surface of the positive electrode current collector, and the blade was moved horizontally along the surface of the positive electrode current collector to remove the positive electrode active material layer. Then, a second constant velocity analysis was performed at a position 10 ㎛ backward from the first position under the same conditions as the first constant velocity analysis. The data measured in the second constant velocity analysis were used.

The vertical adhesion of the positive electrode active material layer was measured in the positive electrode active material layer, and the measured data was normalized to the adhesion graph area to derive the vertical relative adhesion force (F _VR ) according to the depth of the positive electrode active material layer.

The vertical adhesion of the positive electrode active material layer was measured using data from a first point 5% away from the surface of the positive electrode active material layer to a second point 5% away from the surface of the electrode current collector, with respect to the entire thickness of the positive electrode active material layer. That is, data near the surface of the positive electrode active material layer and near the surface of the electrode current collector were excluded to prevent measurement errors.

The change rate of vertical relative force (F _VR ) of the derived positive electrode active material layer was calculated using the following mathematical expression 1 from the vertical relative force (F _VR ) data. In addition, the arithmetic mean was also calculated from the vertical relative force (F _VR ) data of the derived positive electrode active material layer.

<Mathematical formula 1>

Rate of change of vertical relative force (F _VR ) = [(maximum vertical relative force - minimum vertical relative force) / minimum vertical relative force] × 100

As a result of the measurement, the rate of change in the vertical relative bonding force of the positive electrode active material layer included in the dry positive electrode of Example 1 was 300% or less.

Therefore, it was confirmed that the positive electrode active material layer (i.e., dry electrode film) of Example 1 had uniform bonding strength and composition distribution regardless of the position along the thickness direction of the positive electrode active material layer.

In contrast, the positive electrode active material layer included in the wet positive electrode of Comparative Example 3 had a change rate in the vertical relative bonding force of more than 400%.

Accordingly, it was confirmed that the cathode active material layer of Comparative Example 3 had a bonding force and composition distribution that significantly changed depending on the position in the thickness direction of the cathode active material layer.

Evaluation Example 2: Evaluation of horizontal bonding strength of positive electrode active material layer (II)

The bonding characteristics of the cathode active material layer included in the dry cathode manufactured in Example 1 and the wet cathode manufactured in Comparative Example 3 were analyzed using SAICAS (SAICAS EN-EX, Daipla Wintes, JAPAN).

Using a diamond blade with a width of 1 mm, constant velocity analysis was performed under the conditions of a clearance angle of 10°, a rake angle of 20°, a shear angle of 45°, a horizontal velocity of 4 ㎛/s, and a vertical velocity of 0.4 ㎛/s to measure the horizontal force (F _H ) according to depth.

First, a first constant velocity analysis was performed from the first position on the surface of the positive electrode active material layer to the surface of the positive electrode current collector, and the blade was moved horizontally along the surface of the positive electrode current collector to remove the positive electrode active material layer. Then, a second constant velocity analysis was performed at a position 10 μm backward from the first position under the same conditions as the first constant velocity analysis. The data measured in the second constant velocity analysis were used.

For the entire thickness of the cathode active material layer, the first horizontal bonding force (F _H1 , Horizontal Force) at a first point 10% away from the surface of the cathode active material layer and the second horizontal bonding force (F _H2 , Horizontal Force) at a second point 10% away from the surface of the cathode current collector were measured.

The ratio of horizontal bonding forces between the first and second points is defined by the following mathematical expression 2.

<Mathematical formula 2>

Horizontal bonding force ratio of point 1 and point 2 (%) = [F _H2 /F _H1 ] × 100

As a result of the measurement, the ratio of the horizontal relative bonding force of the positive electrode active material layer of Example 1 was 60% or more.

In contrast, the horizontal bonding strength ratio of the positive electrode active material layer of Comparative Example 3 was less than 50%.

That is, the ratio of the horizontal relative bonding force of the positive electrode active material layer of Example 1 increased compared to that of the positive electrode active material layer of Comparative Example 3.

Therefore, it was confirmed that the positive electrode active material layer (i.e., dry electrode film) of Example 1 had more uniform bonding strength and composition distribution than the positive electrode active material layer of Comparative Example 3.

Evaluation Example 3: Evaluation of room temperature charge/discharge characteristics

The lithium batteries manufactured in Examples 1 to 4 and Comparative Examples 1 to 2 were charged under constant current at 25°C at a current of 0.1 C rate until the voltage reached 4.4 V (vs. Li), and then cut-off at a current of 0.05 C rate while maintaining 4.4 V in constant voltage mode. Subsequently, the batteries were discharged under constant current at 0.1 C rate until the voltage reached 2.8 V (vs. Li) during discharge (formation cycle).

The lithium battery that had undergone the Mars cycle was charged at a constant current of 0.5 C rate at 25°C until the voltage reached 4.4 V (vs. Li). Then, the battery was discharged at a constant current of 0.5 C rate until the voltage reached 2.8 V (vs. Li), and this cycle was repeated under the same conditions up to the ^100th cycle (repeated 100 times).

In all charge/discharge cycles, a pause of 10 minutes was allowed after one charge/discharge cycle. Some of the results of the room temperature charge/discharge experiments are shown in Table 1 below. The capacity retention at the ^100th cycle is defined by the following mathematical expression 3.

<Mathematical Formula 3>

Capacity retention rate [%] = [Discharge capacity at ^100th cycle / Discharge capacity at ^1st cycle] × 100

Capacity retention rate [%] Example 1 95 Example 2 96 Example 3 95 Example 4 96 Comparative Example 1 88 Comparative Example 2 85

As shown in Table 1, the lithium batteries of Examples 1 to 4 showed improved room temperature life characteristics compared to the lithium batteries of Comparative Examples 1 to 2.

It was determined that the lithium battery of Comparative Example 1 had a reduced lifespan due to an increase in side reactions caused by burrs and/or depressions formed adjacent to the outer periphery of the cathode active material layer by laser cutting.

It was determined that the lithium battery of Comparative Example 2 had a deteriorated life characteristic due to side reactions caused by cracks formed on the surface of the positive electrode active material layer in addition to side reactions caused by burrs and/or depressions formed adjacent to the outer periphery of the positive electrode active material layer by laser cutting.

Claims (24)

A step of providing a metal layer at a first speed;
A step of providing a dry electrode film at a second speed and intermittently providing the film at a third speed that is lower than the second speed; and
A step of intermittently disposing the dry electrode film on one or both sides of the metal layer to form a dry electrode active material layer,
While providing the dry electrode film at the second speed, the dry electrode film is disposed on the metal layer,
A method for manufacturing a dry electrode, wherein the dry electrode film is undisposed on the metal layer while the dry electrode film is provided at the third speed. In the first paragraph, the first speed of providing the metal layer is the speed of providing the dry electrode,
The first speed for providing the metal layer and the second speed for providing the dry electrode film are equal to each other,
A method for manufacturing a dry electrode, wherein the third speed for providing the dry electrode film is less than 10% to 100% of the second speed for providing the dry electrode film. In the first paragraph, the dry electrode film is a self-standing film,
The above dry electrode film further includes one or more cutting lines introduced along a direction orthogonal to the longitudinal direction of the above dry electrode film,
A method for manufacturing a dry electrode, wherein a dry electrode film including the above-described cutting line is supported by a support before being placed on the metal layer. A method for manufacturing a dry electrode, wherein in the first aspect, the metal layer further comprises an interlayer disposed on one or both sides of the metal layer at a first speed. In the fourth paragraph, the metal layer includes a plurality of first regions spaced apart along the longitudinal direction of the metal layer and one or more second regions intermittently arranged between the plurality of first regions,
A dry electrode manufacturing method, wherein the intermediate layer is selectively disposed in the first region among the first region and the second region. In the fifth paragraph, the dry electrode film is disposed on the intermediate layer of the first region while the dry electrode film is provided at the second speed,
A method for manufacturing a dry electrode, wherein the dry electrode film is undisposed in a second region of the metal layer while the dry electrode film is provided at a third speed. A method for manufacturing a dry electrode, wherein the total area of the dry electrode active material layer in the first paragraph is 99% or less of the total area of the dry electrode. In the first paragraph, the dry electrode active material layer is arranged at a first distance apart at a uniform interval along the length direction of the dry electrode,
The above dry electrode film further includes a plurality of cutting lines introduced along a direction orthogonal to the longitudinal direction of the above dry electrode film,
A method for manufacturing a dry electrode, wherein the second distance between the plurality of cutting lines is less than 10% to 100% of the first distance. A method for manufacturing a dry electrode, wherein in the first paragraph, the dry electrode active material layers are arranged to be spaced apart from each other along the length direction of the dry electrode, and the gap between the dry electrode active material layers arranged to be spaced apart from each other is smaller than the width of the dry electrode. A method for manufacturing a dry electrode, wherein in the first paragraph, a step of removing a dry electrode film disposed on the metal layer is absent. A method for manufacturing a dry electrode, wherein, in the first paragraph, a surface of a metal layer adjacent to the dry electrode active material layer is free of burrs or depressions. A method for manufacturing a dry electrode, wherein the step of forming the dry electrode active material layer in the first paragraph includes the step of laminating the dry electrode film and the metal layer. A method for manufacturing a dry electrode, wherein in the first aspect, the step of forming the dry electrode active material layer further includes a step of applying heat, pressure, or a combination thereof to at least one of the dry electrode film and the metal layer. In the first aspect, the step of forming the dry electrode active material layer includes the step of simultaneously providing the dry electrode film and the metal layer between the first laminator roll and the second laminator roll,
At least one of the first laminator roll and the second laminator roll further includes an intake port for mechanically attaching the dry electrode film to at least one of the first laminator roll and the second laminator roll,
The dry electrode film further includes at least one cutting line formed along the machine direction while attached to at least one of the first laminator roll and the second laminator roll,
A dry electrode manufacturing method, wherein an opening having a length formed along the axial direction (TD, transverse direction) is free in at least one of the first laminator roll and the second laminator roll. In the 14th paragraph, while the first region of the metal layer and the dry electrode film are simultaneously provided between the first laminator roll and the second laminator roll, the first laminator roll and the second laminator roll have the first rotation speed,
A method for manufacturing a dry electrode, wherein the first laminator roll and the second laminator roll have a first rotation speed or at least one of the first laminator roll and the second laminator roll has a second rotation speed lower than the first rotation speed while the second region of the metal layer is provided between the first laminator roll and the second laminator roll and the dry electrode film is not provided between the first laminator roll and the second laminator roll. In the fourth paragraph, the intermediate layer includes a binder,
The above binder comprises at least one selected from a conductive binder and a non-conductive binder,
The above binder comprises a fluorine-based binder,
A method for manufacturing a dry electrode, wherein the thickness of the intermediate layer is 30% or less of the thickness of the metal layer. A method for manufacturing a dry electrode, wherein the intermediate layer further includes a conductive material, and the conductive material includes a carbon-based conductive material. In the first paragraph, the dry electrode film is free of residual processing solvent,
The above dry electrode film comprises a dry electrode active material and a dry binder, the dry binder comprises a fibrillized binder, and the dry binder comprises a fluorine-based binder.
A method for manufacturing a dry electrode, wherein the dry electrode film further includes a dry conductive material, and the dry conductive material includes a carbon-based conductive material. A method for manufacturing a dry electrode, wherein in the first paragraph, the dry electrode active material layer has a change rate in a vertical relative binding force (F VR) according to a depth from a first point spaced 5% apart from the surface of the dry electrode active material layer in the direction of the metal layer to a second point spaced 5% apart from the surface of the metal layer of 300% or less when measured by a surface and interfacial measuring analysis system ( _SAICAS ). A method for manufacturing a dry electrode, wherein in the first paragraph, the dry electrode active material layer has a horizontal binding force ratio of a second horizontal binding force (F H2) at a second point located 10% away from the surface of the metal layer to a first horizontal binding force (F _H1 ) at a first point located 10% away from the surface of the dry electrode active material layer in the direction of the metal layer with respect to the entire thickness of the dry electrode active material layer when measured by _SAICAS , of 50% or more. It includes a first laminator roll and a second laminator roll which are arranged spaced apart from each other,
At least one of the first laminator roll and the second laminator roll has a second rotational peripheral speed and is configured or driven to intermittently have a third rotational peripheral speed that is smaller than the second rotational peripheral speed,
A dry electrode manufacturing device, wherein the first laminator roll and the second laminator roll have opposite rotation directions. In the 21st paragraph, further comprising a first winding roll,
A metal layer is wound on the first winding roll,
The metal layer is provided between the first laminator roll and the second laminator roll from the first winding roll at a first speed,
Providing a dry electrode film at a second speed from at least one of the first laminator roll and the second laminator roll on the metal layer, and intermittently providing the film at a third speed that is lower than the second speed,
While providing the dry electrode film at the second speed, the dry electrode film is disposed on the metal layer,
A dry electrode manufacturing device, wherein the dry electrode film is undisposed on the metal layer while the dry electrode film is provided at the third speed. A dry electrode manufactured by a method according to any one of claims 1 to 20. A lithium battery comprising a dry electrode according to claim 23.

Images