KR102727051B1 - Electrochemical device, and preparation method thereof - Google Patents

Abstract

An electrochemical device comprising: a positive electrode current collector; a plurality of positive electrodes in electrical contact with the positive electrode current collector; an electrolyte layer including a second protrusion and a second depression, each positioned on a first protrusion formed by the positive electrode and a first depression positioned between the positive electrodes; and a negative electrode current collector layer including a third protrusion and a third depression, each positioned on the second protrusion and the second depression of the electrolyte layer; and a method for manufacturing the same are provided.

Description

{Electrochemical device, and preparation method thereof}

It relates to an electrochemical device and a method for manufacturing the same.

With the advancement of technology in the electronics field, the market for various mobile electronic devices such as mobile phones, game consoles, PMP (portable multimedia players), MP3 (mpeg audio layer-3) players, as well as smart phones, smart pads, e-book readers, tablet computers, and mobile medical devices attached to the body is growing rapidly. As the market for such mobile electronic devices grows, the demand for batteries suitable for operating mobile electronic devices is also increasing.

Secondary batteries are batteries that can be charged and discharged, unlike primary batteries that cannot be recharged. In particular, lithium secondary batteries have the advantage of higher voltage and higher energy density per unit weight than nickel-cadmium batteries or nickel-hydrogen batteries. Recently, research is also being conducted on lithium secondary batteries using electrodes with a three-dimensional (3D) structure to increase capacity.

One aspect is to provide an electrochemical device including a negative electrode current collector layer having a structure capable of effectively accommodating a change in the volume of the electrochemical device during charge and discharge and a positive electrode having a composition capable of improving the thickness uniformity of the lithium negative electrode.

On one side,

Bipolar collector;

A plurality of anodes in electrical contact with the cathode collector;

An electrolyte layer including a second protrusion and a second depression, each of which is positioned on a first protrusion formed by the anode and a first depression positioned between the anode; and

An electrochemical device is provided, comprising: a negative electrode current collector layer including a third protrusion and a third recessed portion, each of which is disposed on a second protrusion and a second recessed portion of the electrolyte layer.

On the other hand,

Bipolar collector;

A plurality of anodes in contact with the above cathode collector;

An electrolyte layer in contact with the plurality of anodes; and

An electrochemical device is provided, comprising a cathode current collector layer arranged along the surface contour of the electrolyte layer.

On another note,

Bipolar collector;

A cathode comprising a compound containing an active metal, which is in contact with the above cathode current collector and has a lower initial charge/discharge efficiency than the cathode active material:

An electrolyte layer in contact with the above anode; and

An electrochemical device is provided, comprising a cathode current collector layer in contact with the electrolyte layer.

According to one aspect, a negative electrode current collector layer having a three-dimensional structure can alleviate stress caused by volume change of an electrochemical device during charge and discharge, and a positive electrode including a compound having low initial charge and discharge efficiency can improve the thickness uniformity of a lithium negative electrode, thereby suppressing capacity decrease and structural collapse of an electrochemical device.

Figure 1 is a perspective view schematically illustrating the structure of an electrochemical device according to one embodiment.
Figure 2 is a perspective view partially showing the interior of the electrochemical device of Figure 1.
FIG. 3 is a cross-sectional view showing only a portion of the cross-section of the electrochemical device of FIG. 1.
Figure 4a is a cross-sectional view of the electrochemical device of Figure 1.
Figure 4b is a cross-sectional view of an electrochemical device according to another embodiment.
Figure 4c is a cross-sectional view of an electrochemical device according to another embodiment.
Figure 5 is a cross-sectional view of an electrochemical device according to another embodiment.
Figure 6 is a cross-sectional view of an electrochemical device according to another embodiment.
Figure 7 is a cross-sectional view of an electrochemical device according to another embodiment.
Figure 8 is a cross-sectional view of an electrochemical device according to another embodiment.
Figure 9 is a perspective view showing the module.
Figure 10 is a cross-sectional view showing the side step coverage.
Figures 11a to 11f are perspective views and cross-sectional views showing a method for manufacturing an electrochemical device.

Hereinafter, with reference to the attached drawings, an electrochemical device according to exemplary embodiments and a method for manufacturing the same will be described in more detail.

In the drawings below, the same reference numerals refer to the same components, and the sizes of each component in the drawings may be exaggerated for clarity and convenience of explanation. In addition, the embodiments described below are merely exemplary, and various modifications are possible from these embodiments. In addition, in the layer structure described below, the expressions "upper" or "upper" may include not only what is directly above in contact, but also what is above in a non-contact manner.

FIG. 1 is a perspective view schematically showing the structure of an electrochemical device according to one embodiment, and FIG. 2 is a cross-sectional view partially showing the interior of the electrochemical device of FIG. 1. FIG. 3 is a cross-sectional view showing only the cathode current collector and the cathode in the electrochemical device of FIG. 1, omitting the rest for the sake of explanation. FIG. 4a is a cross-sectional view of the electrochemical device of FIG. 1.

Referring to FIGS. 1 to 4A, an electrochemical device (100) according to one embodiment includes a positive electrode current collector (101), a positive electrode (102), an electrolyte layer (120), and a negative electrode current collector layer (111). A plurality of positive electrodes (102) are in electrical contact with the positive electrode current collector (101) and may be arranged in a direction protruding from the positive electrode current collector (101) (for example, the z direction in FIG. 2). The electrolyte layer (120) includes a second protrusion (120a) and a second recess (120b), and the second protrusion (120a) and the second recess (120b) may be arranged on a first protrusion (102a) formed of the positive electrode (102) and a first recess (102b) positioned between the positive electrode (102), respectively. The negative electrode current collector layer (111) includes a third protrusion (111a) and a third recessed portion (111b), and the third protrusion (111a) and the third recessed portion (111b) can be respectively disposed on the second protrusion (120a) and the second recessed portion (120b) included in the electrolyte layer (120).

Referring to Fig. 4a, an empty space formed by a third recessed portion (111b) is arranged between a plurality of third protrusions (111a). This empty space can effectively accommodate a change in volume of the electrochemical device (100) accompanying charge and discharge, for example, a change in volume of the negative electrode (112) (see Fig. 5), thereby preventing deterioration such as cracks. As a result, the life characteristics and stability of the electrochemical device (100) can be improved.

Referring to FIG. 4b, a sheet-shaped negative electrode collector (113) may be additionally arranged on the negative electrode collector (111). The sheet-shaped negative electrode collector (113) may surround a hollow space formed by a third depression (111b) between a plurality of third protrusions (111a). The hollow space may be filled with an inert gas such as nitrogen or argon, but is not necessarily limited thereto, and any gas that does not participate in an electrochemical reaction and does not deteriorate the battery may be used. The pressure of the hollow space may be atmospheric pressure (1 atm) or lower than atmospheric pressure at room temperature. The sheet-shaped negative electrode collector (113) may be, but is not necessarily limited thereto, a metal foil, and may be a conductive material formed in a sheet shape by a conductive slurry or sputtering, etc.

Referring to FIG. 4c, a buffer layer (114) may be additionally arranged to fill the empty space formed by the third recessed portion (111b) between the plurality of third protrusions (111a). The buffer layer (114) effectively accommodates an increase in the volume of the negative electrode (112) when charging the electrochemical device (100) and facilitates the return of the negative electrode current collector layer (111) to its pre-charge form accompanying the decrease in the volume of the negative electrode (112) when discharging, thereby preventing deterioration such as cracking of the electrochemical device (100).

The buffer layer (114) may include an elastic material that is easy to change in volume due to an external force. The elastic material may be, for example, one or more selected from natural rubber and synthetic rubber. The synthetic rubber may be, for example, styrene-butadiene rubber (SBR), butadiene rubber (BR), isoprene rubber (IR), ethylene-propylene-diene monomer (EPDM) rubber, silicone rubber, alkyl acrylate copolymer, styrene-ethylene-butadiene-styrene copolymer, polymethylsilane rubber, butyl acrylate copolymer, etc., but is not necessarily limited thereto, and any material that can be used as an elastic material in the relevant technical field may be used. The elastic material may additionally include a conductive material. The conductive material may be a carbon-based conductive material and/or a metal-based conductive material. The conductive material may be carbon black, graphite particles, natural graphite, artificial graphite, acetylene black, Ketjen black, carbon fiber; carbon nanotube; It may be, but is not limited to, metal powders such as copper, nickel, aluminum, silver, or metal fibers or metal tubes; conductive polymers such as polyphenylene derivatives, and the like; and any material that can be used as a conductive material in the relevant technical field may be used.

The buffer layer (114) may be at least partially empty. In other words, the elastic material may be disposed only in a portion of the buffer layer (114) and the remaining portion may be empty, and the volume occupied by the elastic material may be 90 vol% or less, 70 vol% or less, 50 vol% or less, 30 vol% or less, 20 vol% or less, or 10 vol% or less, and the remaining portion may be empty space. The elastic material disposed in the buffer layer (114) may be porous. By disposing the porous elastic material in the buffer layer (114), the volume change of the electrochemical device (100) accompanying the charging and discharging can be accommodated more effectively.

Referring to FIGS. 1 to 4c, the third protrusions (111a) and the third recesses (111b) of the negative electrode current collector layer (111) can be arranged in parallel, alternately, regularly, or periodically. The regular or periodic arrangement of a plurality of third protrusions (111a) and third recesses (111b) can improve the structural uniformity of the electrochemical device (100), thereby preventing deterioration of the electrochemical device (100).

Referring to FIG. 2 and FIGS. 4a to 4c, the third recessed portion (111b) of the negative electrode current collector layer (111) includes side surfaces and a bottom surface that are spaced apart from each other and face each other. The angle formed by the side surface and the bottom surface of the third recessed portion (111b) may be 60 degrees or more, 65 degrees or more, 70 degrees or more, 75 degrees or more, 80 degrees or more, 85 degrees or more, or 80 to 100 degrees.

The distance between the opposing side surfaces of the third recessed portion (111b) may be 5 µm to 30 µm, 6 µm to 25 µm, 7 µm to 20 µm, or 8 µm to 18 µm.

The depth of the third recessed portion (111b), that is, the distance from the surface of the electrochemical device (100) to the bottom surface of the third recessed portion (111b), may be 60 µm to 300 µm, 80 µm to 250 µm, 100 µm to 230 µm, or 120 µm to 200 µm. When the third recessed portion (111b) has such an angle, distance, and depth, the structural stability and energy density of the electrochemical device (100) are increased, and an increased discharge capacity can be implemented in the same space.

The thickness of the negative electrode current collector layer (111) may be 5 ㎛ or less, 4.5 ㎛ or less, 4.0 ㎛ or less, 3.5 ㎛ or less, 3.0 ㎛ or less, 2 ㎛ or less, 1 ㎛ or less, 0.5 ㎛ or less, or 0.1 ㎛ or less, and may be 0.01 ㎛ or more, or 0.05 ㎛ or more. Since the thickness of the negative electrode current collector layer (111) is 5 ㎛ or less, the weight fraction occupied by the current collector is reduced, so that the energy density per unit weight of the electrochemical device (100) may increase.

The plurality of third protrusions (111a) and third depressions (111b) of the negative electrode current collector layer (111) can be electrically connected to each other, and this electrical connection can be maintained even after 100 or more charge/discharge cycles. Even after 100 or more charge/discharge cycles, the surface resistance of the negative electrode current collector layer (111) can be 101% or less, 104% or less, 105% or less, 110% or less, or 120% or less of the initial surface resistance before charge/discharge.

Referring to FIGS. 1 to 4c, the positive electrode (102) may include an active metal-containing compound having an initial charge/discharge efficiency lower than that of the positive electrode active material. Such a material may be uniformly disposed throughout the positive electrode (102) or may be distributed in some areas. For example, such a material may be primarily disposed in a portion of the positive electrode (102) adjacent to the electrolyte layer (120).

During the initial charge, the active metal-containing compound having a lower initial charge/discharge efficiency than the positive electrode active material in the positive electrode (102) is oxidized and separated into active metal ions, electrons, and the oxidation reaction product of the active metal-containing compound. The active metal ions move from the positive electrode (102) to the electrolyte layer (120), and the electrons move to the negative electrode current collector layer (111) through the positive electrode current collector layer (101) and the external circuit, so that the active metal ions reduced by the electrons are plated between the negative electrode current collector layer (111) and the electrolyte layer (120), thereby forming an active metal bed such as a lithium bed. Subsequently, during the initial discharge, the active metal in the active metal bed is oxidized and separated into active metal ions and electrons, and the active metal ions move from the active metal bed to the electrolyte layer (120), and the electrons move to the positive current collector layer (101) through the negative current collector layer (111) and the external circuit, so that the oxidation reaction product of the active metal-containing compound in the positive electrode (102) is reduced by the active metal ions and electrons, and the active metal-containing compound is formed again. Since the initial charge/discharge efficiency of the active metal-containing compound is low, only a part of the active metal ions used to form the active metal bed during the initial charge returns to the positive electrode (102) during discharge, so a part of the active metal bed remains to become the negative electrode, and a part of the oxidation reaction product of the active metal-containing compound also remains in the positive electrode (102). The initial positive electrode (102) contains only an active metal-containing compound having an initial charge/discharge efficiency lower than that of the positive electrode active material, and the positive electrode (102) after the initial charge/discharge additionally contains the oxidation reaction product of the active metal-containing compound.

As a result, after the initial charge and discharge, the negative electrode (112) is formed between the negative electrode current collector layer (111) and the electrolyte layer (120), as shown in FIG. 5. Unlike a negative electrode disposed by a conventional method such as deposition, such a negative electrode (112) can be disposed between the negative electrode current collector layer (111) and the electrolyte layer (120) with a uniform thickness. Accordingly, the capacity of the electrochemical device (100) is reduced and the electrode structure is collapsed during the charge and discharge process due to the non-uniform thickness of the negative electrode (112), thereby improving the life characteristics and stability of the electrochemical device (100).

The initial charge/discharge efficiency of the active metal-containing compound having lower initial charge/discharge efficiency than the positive electrode active material may be 50% or less. In this case, only 50% or less of the active metal deposited between the negative electrode current collector layer (111) and the electrolyte layer (120) is oxidized during discharge, and the remaining active metal remains as it is, so that the negative electrode (112) can be formed. The initial charge/discharge efficiency of the active metal-containing compound having lower initial charge/discharge efficiency than the positive electrode active material in the electrochemical device (100) may be 45% or less, 40% or less, 35% or less, 30% or less, 25% or less, 20% or less, 15% or less, or 10% or less.

The active metal-containing compound having lower initial charge/discharge efficiency than the cathode active material may be at least one selected from Li ₃ N, Li ₂ NiO ₂ , and Li ₂ MnO, but is not necessarily limited thereto, and any compound containing an active metal that has lower initial charge/discharge efficiency than the cathode active material used in an electrochemical device in the relevant technical field may be used.

The content of the active metal-containing compound having lower initial charge/discharge efficiency than that of the positive electrode active material may be 10% or less, 5% or less, 3% or less, or 0.5% or less of the total weight of the positive electrode (102). If the content of the active metal-containing compound having lower initial charge/discharge efficiency than that of the positive electrode active material is too high, the content of the positive electrode active material decreases, which reduces the capacity of the electrochemical device, and if it is too low, the amount of the active metal bed formed may be insignificant, making it difficult to obtain a uniform negative electrode.

Referring to FIG. 6, the positive electrode (102) may include an irreversible layer (102c) in contact with the electrolyte layer (120) and a reversible layer (102d) in contact with the positive electrode current collector (101). The irreversible layer (102c) may include an active metal-containing compound having lower initial charge/discharge efficiency than the positive electrode active material. The reversible layer (102d) is disposed between the irreversible layer (102c) and the positive electrode current collector (101) and may include a positive electrode active material. In other words, the positive electrode (102) may have a multilayer structure including the irreversible layer (102c) and the reversible layer (102d). The irreversible layer (102c) may be referred to as a sacrificial layer because some or all of the active metal-containing compound having low initial charge/discharge efficiency may be oxidized and removed by charge/discharge. After the initial charge/discharge, the oxidation reaction product of the active metal-containing compound may remain in the irreversible layer (102c) region. The negative electrode (112) between the electrolyte layer (102) and the negative electrode current collector layer (111) may increase in proportion to the degree to which the irreversible layer (102c) decreases.

The thickness of the irreversible layer (102c) may be 30% or less, 15% or less, 9% or less, or 4% or less of the total thickness of the positive electrode (102). If the thickness of the irreversible layer (102c) is too thick, the content of the positive electrode active material decreases, thereby decreasing the capacity of the electrochemical device. If the thickness of the irreversible layer (102c) is too thin, the amount of the active metal bed generated may be minimal, making it difficult to obtain a negative electrode with a constant thickness. The thickness of the irreversible layer (102c) may be 200 nm or less, 150 nm or less, 100 nm or less, or 50 nm or less. If the thickness of the irreversible layer (102c) exceeds 200 nm, the content of the positive electrode active material may decrease and the resistance may increase.

Referring to FIGS. 2 to 6, in the electrochemical device (100), the positive electrode (102) may be arranged in a flat panel shape on the positive electrode collector (101) in a direction perpendicular to the positive electrode collector (101) and spaced apart from each other. The angle formed between the positive electrode (102) and the positive electrode collector (101) may be 60 to 120 degrees, 70 to 110 degrees, 80 to 100 degrees, or 85 to 95 degrees. The aspect ratio of the height (H) and the width (W) of the cross-section of the positive electrode (102) may be 5 or more, 10 or more, 20 or more, 30 or more, 40 or more, or 50 or more. Since the anode (102) has a flat shape, the contact area between the anode (102) and the electrolyte layer (120) increases and the distance through which the active metal ions move to the electrolyte layer (120) decreases, so that the internal resistance of the electrochemical device (100) decreases, the energy density increases, and the high-rate characteristics can be improved.

The height of the anode (102) (height (H) of FIG. 3) may be 10 ㎛ or more. The height of the anode (102) may be 10 ㎛ to 5 mm, 10 ㎛ to 1 mm, 50 ㎛ to 1 mm, 100 ㎛ to 500 ㎛, 100 ㎛ to 400 ㎛, or 100 ㎛ to 300 ㎛. If the height of the anode (102) is too low, the energy density may decrease, and if it is too high, the structural stability may decrease. The thickness of the anode (102, width (W) of FIG. 3) may be 100 ㎛ or less. The thickness of the anode (102) may be 50 ㎛ or less, 40 ㎛ or less, 30 ㎛ or less, 20 ㎛ or less, 10 ㎛ or less, or 5 ㎛ or less, and may be 0.01 ㎛ or more. As the thickness of the anode (102) decreases, the distance between the ions and the electrolyte layer (120) decreases, which reduces the internal resistance of the electrochemical device (100) and improves the high-rate characteristics.

Although not shown in the drawing, a conductive adhesive layer may additionally be included between the positive electrode (102) and the positive electrode current collector (101). The conductive adhesive layer electrically connects the positive electrode (102) and the positive electrode current collector (101) while bonding them together, and may be formed using a conductive adhesive or conductive paste.

Referring to FIG. 7, the electrochemical device (100) may additionally include a positive electrode conductor layer (105) that is in electrical contact with the positive electrode collector (101) and is inserted into the inside of the positive electrode (102). The positive electrode conductor layer (105) and the positive electrode collector (101) may be manufactured separately using different materials and then bonded, or may be formed integrally using the same conductive material. For example, the positive electrode collector (101) may include a plurality of positive electrode conductor layers (105) that protrude vertically from the surface and extend. Although the positive electrode conductor layer (105) is illustrated in FIG. 7 as having a flat shape, it is not necessarily limited to this shape and may have any shape that can be used as a conductor layer in the relevant technical field. For example, the positive electrode conductor layer (105) may have a fishbone shape, a mesh shape, a lattice shape, etc.

The positive electrode conductor layer (105) may extend from the positive electrode current collector (101) to the electrolyte layer (120) so as to be in contact with the electrolyte layer (120). Since the positive electrode conductor layer (105) extends to the electrolyte layer (120), electrons can easily move to the end of the positive electrode (102). Alternatively, the positive electrode conductor layer (105) may extend from the positive electrode current collector (101) close to the electrolyte layer (120) but may not be in contact with the electrolyte layer (120). The positive electrode conductor layer (105) may be inserted into all or only some of the positive electrodes (102), and the insertion form may be different from each other. A positive electrode (102) having high electronic conductivity may not include the positive electrode conductor layer (105). The thickness of the anode conductor layer (105) may be 3 ㎛ or less, 2 ㎛ or less, 1 ㎛ or less, 0.5 ㎛ or less, or 0.3 ㎛ or less, and may be 0.1 ㎛ or more.

Referring to FIGS. 3 and 8, the electrochemical device (100) may additionally include a support (102e). The support (102e) may be positioned in a first recessed portion (102b) located between the first protrusions (102a) formed of the positive electrode (102), may contact the first protrusions (102a), and may support the first protrusions (102a). The support (102e) may improve the structural stability of the positive electrode (102) positioned in a direction protruding from the positive electrode current collector (101) and may have the same composition as the positive electrode (102). The support (102e) and the first protrusion (102a) may be formed integrally.

Referring to FIG. 9, the electrochemical device (100) may be composed of a module (106) including a plurality of anodes (102). The module (106) has a structure in which a plurality of anodes (102) spaced apart from each other are supported by a support, and the type of the support is not particularly limited. For example, the support may be a partition (103) supporting a side surface of the module (106), a cathode current collector (101) supporting a bottom surface of the module (106), etc. Although not shown in FIG. 9, an electrolyte layer and a cathode current collector layer are laminated on the module (106) to constitute the electrochemical device (100). A cathode may be additionally arranged between the electrolyte layer and the cathode current collector layer.

Referring to FIG. 9, the height (H) of the module (106) may be 10 µm to 5 mm, 10 µm to 1 mm, 50 µm to 1 mm, 100 µm to 500 µm, 100 µm to 400 µm, or 100 µm to 300 µm. The module (106) may include one or more baffles (103) that are in vertical contact with the positive electrode (102). In the module (106), the baffles (103) may be arranged in the x direction perpendicular to the positive electrode (102) that is arranged in the y direction. The baffles (103) may support both sides of the positive electrode (102) to suppress deformation and deterioration of the module (106) due to expansion and/or contraction of the positive electrode (102) during charge and discharge. The length (L) of the module (106) can be 20 µm to 100 mm, 20 µm to 50 mm, 20 µm to 10 mm, 100 µm to 10 mm, 200 µm to 5000 µm, 200 µm to 4000 µm, or 200 µm to 3000 µm. The partition wall (103) can have a different composition from the anode (102) or can have the same composition.

The positive electrode current collector (101) may be in the form of a flat sheet. The thickness of the positive electrode current collector (101) may be 30 ㎛ or less, 20 ㎛ or less, 10 ㎛ or less, 5 ㎛ or less, 3 ㎛ or less, or 0.01 ㎛ to 30 ㎛. As shown in FIG. 9, the module (106) may not include a partition wall (103) as a support, and may include only the positive electrode current collector layer (101).

As shown in FIG. 5, the negative electrode (112) may be placed between the negative electrode current collector layer (111) and the electrolyte layer (120). In the foregoing, the method in which the negative electrode (112) is placed between the negative electrode current collector layer (111) and the electrolyte layer (120) by charging and discharging the electrochemical device (100) has been described, but the present invention is not necessarily limited to this method. For example, the negative electrode (112) may be placed on the electrolyte layer (120) by a deposition method such as physical vapor deposition (PVD). After the negative electrode (112) having a thin thickness is placed by deposition, the thickness of the negative electrode (112) may be additionally increased by charging and discharging.

The negative electrode (112) may have a conformal layer that matches the contour of the electrolyte layer (120), that is, a layer formed along the surface contour of the electrolyte layer (120). In addition, the negative electrode (112) may have a high side step coverage. Referring to FIG. 10, the side step coverage (SCs) of the negative electrode (112) represented by the following mathematical expression 1 may be 50% or more, 60% or more, 70% or more, 80% or more, 90% or more, 95% or more, or 99% or more. The negative electrode (112) may be disposed between the negative electrode current collector layer (111) and the electrolyte layer (120) by initial charge and discharge, or a thin negative electrode (112) is first disposed by deposition and then the thickness of the negative electrode (112) is increased by charge and discharge, so that the negative electrode (112) may have a high side step coverage.

<Mathematical formula 1>

SCs = Ts/Tt×100

Ts is the thickness of the thinnest covering point in the step, Tt is the covering thickness of the flat surface in the step, H is the height of the step, and W is the width of the step.

The negative electrode (112) may be a layer made of lithium, an active metal alloyable with lithium, sodium, or an active metal alloyable with sodium, and may have a thickness of 3 μm or less, 2 μm or less, or 1 μm or less. For example, the thickness of the negative electrode (112) may be 0.01 to 3 μm, 0.05 to 3 μm, or 0.1 to 3 μm.

Referring to FIG. 2 and FIG. 4a to FIG. 8, the positive electrode (102) and the negative electrode (112) do not directly contact each other and can exchange metal ions such as lithium ions and sodium ions through the electrolyte layer (120). The positive electrode current collector (101) is electrically connected to the positive electrode (102), and the negative electrode current collector layer (111) is electrically connected to the negative electrode (112). The thickness of the electrolyte layer (120) may be 20 ㎛ or less, 15 ㎛ or less, 10 ㎛ or less, 5 ㎛ or less, 4 ㎛ or less, 3 ㎛ or less, 2 ㎛ or less, 1 ㎛ or less, 0.5 ㎛ or less, or 0.1 ㎛ or less, and may be 0.01 ㎛ or more. As the thickness of the electrolyte layer (120) decreases, the ion transfer distance between the positive electrode (102) and the negative electrode (112) decreases, so that the internal resistance decreases and the high-rate characteristics can be improved. When a solid electrolyte is used as an electrolyte layer (120) in an electrochemical device (100), there are no problems such as electrolyte leakage or ignition, so that the stability of the electrochemical device (100) can be improved. The electrochemical device (100) can be manufactured in a small size and can be easily applied to a battery of a small device such as a mobile device or a wearable device. The electrochemical device (100) can be used in, for example, a mobile phone, glasses, a health band, a wristwatch, etc.

The electrochemical device (100) may be a lithium battery, and the positive electrode current collector (101) and the negative electrode current collector layer (111) may be made of conductive metals such as Cu, Au, Pt, Ag, Zn, Al, Mg, Ti, Fe, Co, Ni, Ge, In, Pd, etc., but are not necessarily limited thereto, and any material that can be used as a current collector in the relevant technical field may be used. For example, the positive electrode current collector (101) may be aluminum foil, and the negative electrode current collector layer (111) may be copper (Cu) foil.

The cathode active material of the lithium battery is not particularly limited and any material that can be used as a cathode active material of a lithium battery in the relevant technical field can be used. A compound capable of reversible intercalation and deintercalation of lithium (lithiated intercalation compound) can be used as the cathode active material. The cathode active material can include one or more lithium transition metal oxides selected from the group consisting of lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium iron phosphate, and lithium manganese oxide. Specifically, lithium cobalt oxide of the chemical formula LiCoO ₂ ; lithium nickel oxide of the chemical formula LiNiO ₂ ; lithium manganese oxide of the chemical formula Li _1+x Mn _2-x O ₄ (wherein, x is 0 to 0.33), LiMnO ₃ , LiMn ₂ O ₃ , or LiMnO ₂ ; lithium copper oxide of the chemical formula Li ₂ CuO ₂ ; Lithium iron oxide having the chemical formula LiFe ₃ O ₄ ; lithium vanadium oxide having the chemical formula LiV ₃ O ₈ ; copper vanadium oxide having the chemical formula Cu ₂ V ₂ O ₇ ; vanadium oxide having the chemical formula V ₂ O ₅ ; lithium nickel oxide having the chemical formula LiNi _1-x M _x O ₂ (wherein, M = Co, Mn, Al, Cu, Fe, Mg, B or Ga, and x = 0.01 to 0.3); lithium manganese composite oxide represented by the chemical formula LiMn _2-x M _x O ₂ (wherein, M = Co, Ni, Fe, Cr, Zn or Ta, and x = 0.01 to 0.1) or Li ₂ Mn ₃ MO ₈ (wherein, M = Fe, Co, Ni, Cu or Zn); lithium manganese oxide having the chemical formula LiMn ₂ O ₄ wherein a part of Li is replaced by an alkaline earth metal ion; disulfide compounds; One or more of iron molybdenum oxides having the chemical formula Fe ₂ (MoO ₄ ) ₃ can be selected and used. The cathode active material can be LiCoO ₂ , LiNiO ₂ , LiMn ₂ O ₄ , or LiFePO ₄ .

The negative active material of the lithium battery is also not particularly limited, and any material that can be used as a negative active material of a lithium battery in the relevant technical field may be used. The negative active material may be an alkali metal (e.g., lithium, sodium, potassium), an alkaline earth metal (e.g., calcium, magnesium, barium) and/or certain transition metals (e.g., zinc) or an alloy thereof. In particular, the negative active material may be at least one selected from lithium and a lithium alloy. Lithium metal may be used as the negative active material. When lithium metal is used as the negative active material, a current collector may be omitted. Accordingly, the volume and weight occupied by the current collector can be reduced, and thus the energy density per unit weight of the lithium battery can be improved. An alloy of lithium metal and another negative active material may be used as the negative active material. The other negative active material may be a metal that can be alloyed with lithium. Metals that can be alloyed with lithium may be Si, Sn, Al, Ge, Pb, Bi, Sb Si-Y alloy (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 (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 may be 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. For example, the lithium alloy can be a lithium aluminum alloy, a lithium silicon alloy, a lithium tin alloy, a lithium silver alloy or a lithium lead alloy.

The solid electrolyte included in the electrolyte layer (120) in the lithium battery is not particularly limited, and any solid electrolyte that can be used in the relevant technical field may be used. As solid electrolytes, BaTiO ₃ , Pb(Zr,Ti)O ₃ (PZT), Pb _1-x La _x Zr _1-y Ti _y O ₃ (PLZT)(O≤x<1, O≤y<1), PB(Mg ₃ Nb _2/3 )O ₃ -PbTiO ₃ (PMN-PT), HfO ₂ , SrTiO ₃ , SnO ₂ , CeO ₂ , Na ₂ O, MgO, NiO, CaO, BaO, ZnO, ZrO ₂ , Y ₂ O ₃ , Al ₂ O ₃ , TiO ₂ , SiO ₂ , SiC, lithium phosphate (Li ₃ PO ₄ ), lithium titanium phosphate (Li _x Ti _y (PO ₄ ) ₃ , 0<x<2, 0<y<3), lithium aluminum titanium phosphate (Li _x Al _y Ti _z (PO ₄ ) ₃ , 0<x<2, 0<y<1, 0<z<3), Li _1+x+y (Al, Ga) _x (Ti, Ge) _2-x Si _y P _3-y O ₁₂ (O≤x≤1, O≤y≤1), lithium lanthanum titanate (Li _x La _y TiO ₃ , 0<x<2, 0<y<3), lithium germanium thiophosphate (Li _x Ge _y P _z S _w , 0<x<4, 0<y<1, 0<z<1, 0<w<5), lithium nitride (Li _x N _y , 0<x<4, 0<y<2), lithium phosphate oxynitride (LiPON, Li _x PON _y , 0<x<4, 0<y<2), SiS ₂ (Li _x Si _y S _z , 0<x<3, 0<y<2, 0<z<4) series glass, P ₂ S ₅ (Li _x P _y S _z , 0<x<3, 0<y<3, 0<z<7) series glass, Li ₂ O, LiF, LiOH, Li ₂ CO ₃ , LiAlO ₂ , Li ₂ O-Al ₂ O ₃ -SiO ₂ -P ₂ O ₅ -TiO ₂ -GeO ₂ series ceramics, garnet series ceramics Li _3+x La ₃ M ₂ O ₁₂ (M = Te, Nb, Zr) can be one or more selected from or a combination thereof. For example, the solid electrolyte can be LiPON.

Referring to FIGS. 11A to 11G, a method for manufacturing an electrochemical device according to another embodiment includes a step of arranging a plurality of positive electrodes (102) that are vertically spaced apart and arranged on a positive electrode current collector (101). The step of arranging the positive electrodes (102) includes a step of arranging a plurality of positive electrode active materials (102d); a step of arranging an active metal-containing compound layer (102c) having lower initial charge/discharge efficiency than the positive electrode active materials on the plurality of positive electrode active materials (102d); a step of arranging an active metal-containing compound layer (102c) having lower initial charge/discharge efficiency than the positive electrode active materials on the plurality of positive electrode active materials (102d); an electrolyte layer (120) on the active metal-containing compound layer (102c) having lower initial charge/discharge efficiency than the positive electrode active materials; and a step of arranging a negative electrode current collector layer (111) on an electrolyte layer (120).

An electrochemical device can be manufactured using a module (106) including a plurality of positive electrode active materials. A method for manufacturing an electrochemical device (100) may include the steps of: preparing a module (106) including a plurality of positive electrode active materials; arranging the module (106) on a positive electrode current collector (101); arranging an active metal-containing compound layer (102c) having lower initial charge/discharge efficiency than a positive electrode active material on the module (106); arranging an electrolyte layer (120) on the active metal-containing compound layer (102c) having lower initial charge/discharge efficiency than a positive electrode active material; and arranging an anode current collector layer (111) on the electrolyte layer (120). When the module (106) includes an active metal-containing compound having lower initial charge/discharge efficiency than a positive electrode active material, the step of arranging an active metal-containing compound layer (102c) having lower initial charge/discharge efficiency than a positive electrode active material on the module (106) may be omitted.

Referring to Fig. 11a, a module (106) including multiple anodes is prepared.

Referring to FIG. 11b, a module (106) is placed on a positive electrode collector (101). Although not shown in the drawing, the module (106) may be attached to the positive electrode collector (101) using a conductive adhesive and/or a conductive paste.

Referring to FIG. 11c, an active metal-containing compound layer (102c) having lower initial charge/discharge efficiency than the positive electrode active material is disposed on the module (106). A method for disposing the active metal-containing compound layer (102c) having lower initial charge/discharge efficiency than the positive electrode active material may be, but is not necessarily limited to, deposition, and any method that can be used in the relevant technical field may be used. The deposition method may be CVD (chemical vapor deposition), PVD (physical vapor deposition), etc. The active metal-containing compound having lower initial charge/discharge efficiency than the positive electrode active material may be, but is not necessarily limited to, Li ₃ N, and any material that can be used as an active metal-containing compound having lower initial charge/discharge efficiency than the positive electrode active material in the relevant technical field may be used. The positive electrode (102) may be composed of an irreversible layer (102c) including an active metal-containing compound having lower initial charge/discharge efficiency than the positive electrode active material, and a reversible layer (102d) including a positive electrode active material.

Referring to FIG. 11d, an electrolyte layer (120) is placed on the anode (102). The method of placing the electrolyte layer (120) may be deposition, but is not necessarily limited to deposition, and any method that can be used in the relevant technical field may be used. For example, the deposition method of the electrolyte layer (120) may be CVD, PVD, etc.

Referring to FIG. 11e, an electrochemical device (100) is prepared by arranging a negative electrode current collector layer (111) on an electrolyte layer (120). The method of arranging the negative electrode current collector layer (111) may be deposition, but is not necessarily limited to deposition, and any method that can be used in the relevant technical field may be used. For example, the deposition method of the negative electrode current collector layer (111) may be thermal evaporation, etc.

Referring to FIG. 11f, a negative electrode (112) may be formed between an electrolyte layer (120) and a negative electrode current collector layer (111). The negative electrode (112) may be Li metal, but is not necessarily limited thereto, and any negative electrode active material that can be used as the negative electrode (112) in the relevant technical field may be used. As described above, the negative electrode (112) may be formed from an irreversible layer (102c) by initial charge/discharge, or may be formed by deposition after the electrolyte layer (120) of FIG. 11d is formed and before the negative electrode current collector layer (111) of FIG. 11e is formed.

100 Electrochemical Devices 101 Anode Current Collector
102 Anode 102a First protrusion
102b 1st depression 102c Irreversible layer
102d reversible layer 102e support
103 bulkhead 105 challenge layer
106 Module 107 Sacrificial Layer
111 Negative current collector layer 111a 3rd protrusion
111b 3rd depression 112 cathode
113 Sheet-type cathode collector 114 Buffer layer
120 Electrolyte layer 120a 2nd protrusion
120b 2nd depression 160 1st layer
170 2nd layer 180 cross section

Claims (31)

Bipolar collector;
A plurality of anodes in electrical contact with the cathode collector;
An electrolyte layer including a second protrusion and a second depression, each of which is positioned on a first protrusion formed by the anode and a first depression positioned between the anodes; and
A negative electrode current collector layer including a third protrusion and a third depression, each of which is arranged on the second protrusion and the second depression of the electrolyte layer;
An electrochemical device comprising a void space defined by the third depression. An electrochemical device in which the third protrusion and the third depression of the negative electrode current collector layer are regularly arranged in parallel in the first paragraph. An electrochemical device in which the third protrusion and the third depression of the negative electrode current collector layer are periodically arranged in parallel in the first paragraph. An electrochemical device in accordance with claim 1, wherein the third recessed portion of the negative electrode current collector layer includes side surfaces and a bottom surface that are spaced apart from each other and face each other, and an angle formed by the side surface and the bottom surface is 60 degrees or more. An electrochemical device in accordance with claim 4, wherein the distance between opposing side surfaces of the third recessed portion is 5 ㎛ to 30 ㎛, and the depth of the third recessed portion is 60 ㎛ to 300 ㎛. An electrochemical device in accordance with claim 1, wherein the thickness of the negative electrode current collector layer is 5 μm or less. An electrochemical device in which the third protrusion and the third recess of the negative electrode current collector layer are electrically connected in the first aspect. An electrochemical device in which the electrical connection between the third protrusion and the third depression of the negative electrode current collector layer in the seventh aspect is maintained even after 100 or more charge/discharge cycles. An electrochemical device in accordance with claim 1, wherein the cathode comprises at least one of an active metal-containing compound having lower initial charge/discharge efficiency than a cathode active material and an oxidation reaction product of the active metal-containing compound. An electrochemical device in which the initial charge/discharge efficiency of an active metal-containing compound having a lower initial charge/discharge efficiency than that of the positive electrode active material in clause 9 is 50% or less. An electrochemical device in accordance with claim 9, wherein the active metal-containing compound having a lower initial charge/discharge efficiency than the positive electrode active material is at least one selected from Li ₃ N, Li ₂ NiO ₂ , and Li ₂ MnO ₃ . In the first paragraph, the cathode comprises an irreversible layer in contact with the electrolyte layer; and a reversible layer in contact with the cathode current collector.
The above irreversible layer comprises at least one of an active metal-containing compound having a lower initial charge/discharge efficiency than the positive electrode active material and an oxidation reaction product of the active metal-containing compound,
An electrochemical device wherein the reversible layer comprises a cathode active material. An electrochemical device in claim 12, wherein the thickness of the irreversible layer is 200 nm or less. An electrochemical device comprising a module including a plurality of anodes according to claim 1. An electrochemical device in accordance with claim 14, wherein the module comprises a baffle in contact with a plurality of anodes. An electrochemical device in accordance with claim 15, wherein the baffle has a different composition from the anode. An electrochemical device comprising a cathode disposed between the cathode current collector layer and the electrolyte layer in the first aspect. An electrochemical device in accordance with claim 17, wherein the cathode is a conformal layer that matches the contour of the electrolyte layer. An electrochemical device in accordance with claim 17, wherein the side step coverage of the cathode is 50% or more. An electrochemical device in which the cathode is an active metal layer in the 17th paragraph. Bipolar collector;
A plurality of anodes in contact with the above cathode collector;
An electrolyte layer in contact with the plurality of anodes; and
A negative electrode current collector layer is disposed along the surface contour of the above electrolyte layer;
An electrochemical device wherein the negative electrode current collector layer is arranged along the surface contour of the electrolyte layer and includes protrusions and depressions arranged on the surface contour of the electrolyte layer. An electrochemical device in accordance with claim 21, wherein the negative electrode current collector layer comprises electrically connected protrusions and recesses. An electrochemical device in which the protrusions and depressions of the negative electrode current collector layer are arranged in a regular or periodic manner in parallel in clause 22. An electrochemical device further comprising a cathode disposed between the electrolyte layer and the cathode current collector layer in the 21st paragraph, wherein the cathode is disposed along the surface contour of the electrolyte layer. In the 24th paragraph, the positive electrode is an electrochemical device including at least one of a positive electrode active material, an active metal-containing compound having lower initial charge/discharge efficiency than the positive electrode active material, and an oxidation reaction product of the active metal-containing compound. Bipolar collector;
A cathode comprising a compound containing an active metal, which is in contact with the above cathode current collector and has a lower initial charge/discharge efficiency than the cathode active material:
An electrolyte layer in contact with the above anode; and
A negative electrode current collector layer in contact with the above electrolyte layer;
An electrochemical device wherein the negative electrode current collector layer is arranged along the surface contour of the electrolyte layer and includes protrusions and depressions arranged on the surface contour of the electrolyte layer. An electrochemical device in which the initial charge/discharge efficiency of an active metal-containing compound having a lower initial charge/discharge efficiency than that of the positive electrode active material in clause 26 is 50% or less. An electrochemical device in claim 26, wherein the active metal-containing compound having a lower initial charge/discharge efficiency than the positive electrode active material is at least one selected from Li ₃ N, Li ₂ NiO ₂ , and Li ₂ MnO ₃ . In the 26th paragraph, the cathode comprises an irreversible layer in contact with the electrolyte layer; and a reversible layer in contact with the cathode current collector.
The above irreversible layer comprises an active metal-containing compound having a lower initial charge/discharge efficiency than the positive electrode active material,
An electrochemical device wherein the reversible layer comprises the positive electrode active material. An electrochemical device in claim 29, wherein the thickness of the irreversible layer is 200 nm or less. An electrochemical device in accordance with claim 29, wherein the irreversible layer further comprises a resultant oxidation reaction of the active metal-containing compound.

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