KR101306187B1 - Device for Eliminating Gas from Battery Cell and Method for Manufacturing Battery Cell - Google Patents

Abstract

The present invention is a device for use in the process of removing the gas generated during the activation process of the battery cell in which the electrode assembly and the electrolyte is embedded in the battery case of the laminate sheet comprising a resin layer and a metal layer, the vacuum chamber to which the battery cell is introduced; A jig in which the battery cell is mounted in an inclined state; And a chamber gate that seals the vacuum chamber and is coupled with a jig.

Description

Device for eliminating gas and manufacturing cell of battery cell {Device for Eliminating Gas from Battery Cell and Method for Manufacturing Battery Cell}

The present invention relates to a gas removal apparatus of a battery cell, and more particularly, a process of removing a gas generated during an activation process of a battery cell in which an electrode assembly and an electrolyte are embedded in a battery case of a laminate sheet including a resin layer and a metal layer. An apparatus for use, comprising: a vacuum chamber into which a battery cell is inserted; A jig in which the battery cell is mounted in an inclined state; And a chamber gate that seals the vacuum chamber and is coupled with a jig.

As technology development and demand for mobile devices are increasing, the demand for batteries as energy sources is rapidly increasing, and accordingly, a lot of researches on batteries capable of meeting various demands have been conducted.

Typically, in terms of the shape of a battery, there is a high demand for a prismatic secondary battery and a pouch-type secondary battery which can be applied to products such as mobile phones with a small thickness, and has advantages such as high energy density, discharge voltage, There is a high demand for lithium secondary batteries such as lithium ion batteries and lithium ion polymer batteries.

In addition, secondary batteries are classified according to the structure of the electrode assembly having a cathode / separation membrane / cathode structure. Representatively, a jelly having a structure in which long sheet-shaped anodes and cathodes are wound with a separator interposed therebetween -Roll (electrode) electrode assembly, a stack (stacked type) electrode assembly in which a plurality of positive and negative electrodes cut in units of a predetermined size are sequentially stacked with a separator, and the positive and negative electrodes of a predetermined unit are interposed through a separator And a stacked / folding electrode assembly having a structure in which a bi-cell or full cells stacked in a state are wound.

Recently, a pouch-type battery having a structure in which a stack type or a stack / fold type electrode assembly is incorporated into a pouch type battery case of an aluminum laminate sheet has attracted much attention due to its low manufacturing cost, small weight, and easy shape deformation. Its usage is also gradually increasing.

1, the general structure of the conventional typical pouch type battery is shown typically as an exploded perspective view.

Referring to FIG. 1, the pouch-type battery 10 includes an electrode assembly 30, electrode tabs 40 and 50 extending from the electrode assembly 30, and electrode leads welded to the electrode tabs 40 and 50. And a battery case 20 accommodating the electrodes 60 and 70 and the electrode assembly 30.

The electrode assembly 30 is a power generation element in which an anode and a cathode are sequentially stacked with a separation membrane interposed therebetween. The electrode assembly 30 has a stacked or stacked / folded structure. The electrode tabs 40 and 50 extend from each electrode plate 30 of the electrode assembly 30 and the electrode leads 60 and 70 are connected to a plurality of electrode tabs 40 and 50 extending from each electrode plate, Respectively, and a part of the battery case 20 is exposed to the outside. An insulating film 80 is attached to the upper and lower surfaces of the electrode leads 60 and 70 in order to increase the degree of sealing with the battery case 20 and at the same time to ensure an electrically insulated state.

The battery case 20 provides a space for accommodating the electrode assembly 30 and has a pouch shape as a whole. 1, a plurality of positive electrode taps 40 and a plurality of negative electrode tabs 50 may be coupled to the electrode leads 60 and 70. In the stacked electrode assembly 30, The upper end is spaced from the electrode assembly 30.

Most secondary batteries including the pouch-type battery undergo a process of activating the battery by charging and discharging in the manufacturing process of the battery cell. Thus, in order to manufacture the final battery cell, the gas generated in the activation process must be removed. It is called a degas process.

However, as described above, the apparatus for degassing the gas generated during the activation of the battery cell has a problem in that an insulation resistance defect occurs due to electrolyte contamination inside the sealing part when the battery case is sealed.

In addition, there is a problem that takes a long time to remove the gas inside the battery cell in the degassing process to remove the gas by drilling the sealed end.

Therefore, there is a high need for a technology that can fundamentally solve these problems.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-described problems of the prior art and the technical problems required from the past.

Specifically, an object of the present invention is to configure the jig to be mounted in a state in which the battery cell is inclined in the device used in the process of removing the gas generated during the activation process of the battery cell, so that the electrolyte during sealing of the battery case inside the sealing portion Since it can be prevented from entering into the insulation failure of the battery cell sealing portion due to electrolyte contamination can be prevented in advance.

Still another object of the present invention is to provide a battery cell manufactured by an easy device while ensuring productivity and quality as described above.

Gas removal device according to the present invention for achieving this object,

An apparatus for use in a process of removing a gas generated during an activation process of a battery cell in which an electrode assembly and an electrolyte are embedded in a battery case of a laminate sheet including a resin layer and a metal layer.

A vacuum chamber into which a battery cell is inserted;

A jig in which the battery cell is mounted in an inclined state; And

A chamber gate that seals the vacuum chamber and is coupled with a jig;

It consists of a structure that includes.

Therefore, the gas removal device according to the present invention, since the jig is configured so that the battery cell is mounted in an inclined state, the electrolyte solution flows to the outside even after front cutting the gas pocket portion of the battery cell to contaminate the battery cell and the gas removal device. Can be prevented.

In addition, as described above, after the gas pocket is completely cut and the gas is discharged to the outside, the electrolyte is introduced into the sealing part in the process of sealing the inside of the unsealed part by heat fusion, thereby causing an insulation resistance defect in the sealing part. It can prevent.

In addition, since the gas can be completely removed by the vacuum chamber, the quality of the battery cell, that is, the high heat fusion bonding force of the sealing part can improve the safety and life characteristics of the battery cell.

For reference, the lithium secondary battery uses, for example, a lithium transition metal oxide such as LiCoO ₂ as a positive electrode active material and a carbon material as a negative electrode active material, and a porous separator such as polyolefin is interposed between the negative electrode and the positive electrode, and LiPF ₆ or the like. It is prepared by putting a non-aqueous electrolyte solution containing a lithium salt of. During charging, lithium ions of the positive electrode active material are released and inserted into the carbon layer of the negative electrode, and during discharge, lithium ions of the negative electrode carbon layer are released and inserted into the positive electrode active material, wherein the non-aqueous electrolyte solution is lithium ions between the negative electrode and the positive electrode. It acts as a medium for moving the. Such a lithium secondary battery should basically be stable in the operating voltage range of the battery and have a performance capable of transferring ions at a sufficiently high speed.

However, since gas is generated as the electrolyte is decomposed on the surface of the negative electrode active material during the continuous charge / discharge process, an SEI film is formed on the surface of the negative electrode active material during the initial charge and discharge process to suppress additional gas generation. Therefore, the battery cell activation process is necessary for the formation of such an SEI film and is required before the final battery cell is manufactured.

The jig is a structure that can be mounted in a state in which the battery cell is inclined so that the portion of the battery cell to be sealed after the gas discharge, there is no particular limitation, for example, may be made of various structures as follows have.

In one preferred example, the jig may be composed of a main body portion for mounting one end of the battery cell, and a protrusion in which the other end extends upward so that the battery cell is mounted in an inclined state.

The protruding portion may have a structure having a height of 10% to 200% based on the height of the main body, and specifically, when the protruding portion is less than 10% based on the height of the main body, preventing contaminants from flowing into the battery cell during sealing. If it is difficult to do and exceeds 200%, the overall size of the degassing device is increased, which is not preferable.

In the main body portion, a groove is formed in the height direction of the battery cell at a portion corresponding to the end to mount the end of the battery cell, it is possible to achieve a stable mounting of the battery cell to the jig.

The top surface of the protruding portion has an inclined surface corresponding to the inclination angle of the battery cell, thereby achieving stable mounting of the battery cell.

In another preferred example, the jig is composed of a main body on which the battery cell is mounted, the upper surface of the main body may be an inclined surface mounted in the inclined state.

The inclined surface is preferably made of an inclination angle of 5 degrees to 70 degrees with respect to the horizontal bottom surface of the jig so as to reduce the electrolyte contamination inside the sealing portion during sealing.

On the other hand, the chamber gate may have a structure further comprising a gripper for fixing the side sealing end of the battery cell.

Since the gripper fixes the cutting portion even after the entire opening of the battery case is cut, it is possible to prevent the scrap of the cut pouch from falling into the chamber.

In some cases, the gripper may have a structure integrally mounted to the chamber gate.

Preferably, the gripper may have a structure in which a cutter cuts the side sealing end of the battery cell to discharge gas and fixes the cut side sealing end.

The laminate sheet according to the present invention may preferably consist of a laminated structure of an outer resin layer, an air and moisture barrier metal layer, and a heat sealable inner resin layer.

The outer resin layer must have excellent resistance to the external environment, and therefore, a tensile strength and weather resistance higher than a predetermined level are required. In this respect, the polymer resin of the outer coating layer may include polyethylene naphthalate (PEN), polyethylene terephthalate (PET), or stretched nylon having excellent tensile strength and weatherability.

The outer coating layer may be made of polyethylene naphthalate (PEN) and / or a polyethylene terephthalate (PET) layer may be provided on the outer surface of the outer coating layer.

The polyethylene naphthalate (PEN) has an excellent tensile strength and weatherability even at a thin thickness as compared with polyethylene terephthalate (PET), and thus is preferable for use as an outer coating layer.

The polymer resin of the internal resin layer may be a polymer resin having heat-sealability (thermal adhesiveness), low hygroscopicity to the electrolyte to suppress penetration of the electrolyte, and not swellable or eroded by the electrolyte. More preferably, it may be made of an unoriented polypropylene film (CPP).

In one preferred example, the laminate sheet according to the present invention is characterized in that the thickness of the outer coating layer is 5 to 40 占 퐉, the thickness of the barrier layer is 20 to 150 占 퐉, the thickness of the inner sealant layer is 10 to 50 占 퐉 Structure. When the thickness of each layer of the laminate sheet is too thin, it is difficult to expect a blocking function and strength improvement for the material. On the other hand, if it is too thick, the workability is deteriorated and the thickness of the sheet is increased.

The electrode assembly is not particularly limited as long as it is a structure composed of a positive electrode and a negative electrode, and preferably a wound structure, a stacked structure, and a stack / folding structure. Details of the stacked / folded structure of the electrode assembly are disclosed in Korean Patent Application Laid-Open Nos. 2001-0082058, 2001-0082059 and 2001-0082060, the contents of which are incorporated herein by reference. As a reference.

The present invention also provides a method of manufacturing a battery cell in which an electrode assembly and an electrolyte solution are built in a battery case of a laminate sheet including a resin layer and a metal layer.

Specifically, the battery cell manufacturing method,

(a) injecting the activated battery cell into the vacuum chamber in an inclined state;

(b) fixing the battery cell to a jig located in the vacuum chamber and converting the vacuum chamber into a vacuum;

(c) forming a through part communicating with the inside of the battery case to cut the gas pocket part of the battery cell to discharge the gas inside the battery cell to the outside; And

(d) sealing the inside of the unsealed portion by heat fusion after discharging the gas in the step (c);

It includes.

Therefore, in the battery cell manufacturing method according to the present invention, since the activated battery cell is introduced into the vacuum chamber in an inclined state, the electrolyte solution flows out to the battery cell and the gas removing apparatus even after the gas pocket of the battery cell is completely cut. It can prevent causing contamination.

In addition, as described above, after the gas pocket is completely cut and the gas is discharged to the outside, the electrolyte is introduced into the sealing part in the process of sealing the inside of the unsealed part by heat fusion, thereby causing an insulation resistance defect in the sealing part. It can prevent.

In one preferred embodiment, the battery cell manufacturing method, before the process (a),

(a1) heat-sealing the remaining portions of the battery case except one end of the outer circumferential surface of the battery case while the electrode assembly is mounted;

(a2) injecting electrolyte through the unsealed end and sealing the end by heat fusion; And

(a3) activating a battery cell by performing charging and discharging;

Can be performed.

The battery case may have various forms, and preferably has a quadrangular structure in plan view. In this case, one end portion may be one side edge of the battery case.

In the above structure, the width of one corner is 20% to 300% larger than the width of the remaining corners, it can be configured to seal the end of the one corner in the heat fusion process for activation.

For example, if the width of one edge is less than 20% of the width of the remaining edges, the gas cannot be sufficiently collected in the space of one edge, and if it exceeds 300%, the amount of wasted edge is increased, thereby increasing the manufacturing cost. Not desirable in

In another preferred embodiment, the battery cell manufacturing method, after the step (d), may further include a step of cutting the remaining outer portion.

The present invention also provides a battery cell, characterized in that produced by the above apparatus.

The battery cell may preferably be a lithium secondary battery. The lithium secondary battery comprises a positive electrode, a negative electrode, a separator, and a lithium-containing non-aqueous electrolyte.

The secondary battery as described above may not only be used in a battery cell used as a power source for a small device, but also includes a plurality of battery cells used as a power source for medium and large devices requiring high temperature stability, long cycle characteristics, and high rate characteristics. It can also be preferably used as a unit cell in the battery pack.

Preferred examples of the medium-to-large device include a power tool driven by a battery-based motor; An electric vehicle including an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), and the like; An electric motorcycle including an electric bike (E-bike) and an electric scooter (E-scooter); An electric golf cart, and the like, but the present invention is not limited thereto.

As described above, the gas removal apparatus according to the present invention is configured to mount the jig in a state in which the battery cell is inclined in the device used in the process of removing the gas generated in the activation process of the battery cell, When sealing, it is possible to prevent the electrolyte from entering the sealing part, thereby preventing the insulation failure of the battery cell sealing part due to the electrolyte contamination.

1 is an exploded perspective view of a general structure of a conventional pouch type battery;
2 is a schematic diagram of a gas removal apparatus according to one embodiment of the present invention;
3 is a vertical cross-sectional schematic diagram of FIG. 2;
4 is a schematic diagram showing a structure in which a cutter is added to the gas removing apparatus of FIG. 2;
FIG. 5 is an enlarged schematic view of a portion A of FIG. 4; FIG.
FIG. 6 is an enlarged schematic view of a portion B of FIG. 5; FIG.
FIG. 7 is a schematic diagram showing a structure in which a sealing tool is added to the gas removing apparatus of FIG. 2; FIG.
FIG. 8 is an enlarged schematic view of a portion C of FIG. 7.
9 to 14 are schematic diagrams showing the procedure of the battery cell manufacturing method according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings, but the present invention is not limited by the scope of the present invention.

FIG. 2 is a schematic diagram of a gas removal apparatus according to one embodiment of the present invention, and FIG. 3 is a vertical cross-sectional schematic diagram of FIG. 2.

Referring to these drawings, the gas removal apparatus 200 includes a vacuum chamber (not shown) into which the battery cells 230 are inserted, a jig 220 in which the battery cells 230 are inclined, and a vacuum chamber. The chamber gate 210 is hermetically sealed and coupled with the jig 220.

The jig 220 includes a main body 222 for mounting one end of the battery cell 230, and a protrusion 224 having the other end extended upward to mount the battery cell 230 in an inclined state.

In addition, the protrusion 224 has a height h of approximately 100% based on the height H of the main body 222, and the main body 222 may be attached to the end of the battery cell 230. The groove 226 is formed in the height direction of the battery cell 230 at a portion corresponding to the end of the battery cell 230.

The battery cell 230 is a pouch type secondary battery in which an electrode assembly and an electrolyte are built in a battery case of a laminate sheet including a resin layer and a metal layer, and the laminate sheet is an outer resin layer, an air and moisture barrier metal layer, and a heat seal It consists of a laminated structure of an internal resin layer.

FIG. 4 is a schematic diagram illustrating a structure in which a cutter is added to the gas removing apparatus of FIG. 2, and FIG. 5 is an enlarged schematic diagram of a portion A of FIG. 4.

Referring to these drawings, the chamber gate 210a includes a gripper 240 for fixing the side sealing end of the battery cell 230, and the gripper 240 is integrally mounted to the chamber gate 210. .

In addition, the gripper 240 fixes the cut side sealing end after the cutter 250 cuts the side sealing end of the battery cell 230 to discharge gas.

FIG. 7 is a schematic diagram illustrating a structure in which a sealing tool is added to the gas removing apparatus of FIG. 2, and FIG. 8 is an enlarged schematic diagram of a portion C of FIG. 7.

2 to 5, the battery cell manufacturing method includes: (a) injecting an activated battery cell 230 into a vacuum chamber in an inclined state; (b) fixing the battery cell 230 to the jig 220 positioned in the vacuum chamber and converting the vacuum chamber into a vacuum; (c) forming a through part communicating with the inside of the battery case to cut the gas pocket part of the battery cell 230 by the cutter 250 to discharge the gas inside the battery cell to the outside; And (d) sealing the inside of the unsealed portion by heat sealing using the sealing tool 260 after discharging the gas in step (c).

7 and 8, the gas removing apparatus 200b includes an upper sealing tool 262 and a lower sealing tool 264.

In addition, since the battery cell 230 is inclined by the jig 220, the electrolyte 272 inside the battery cell 230 does not flow into the sealing portion 274 during sealing.

9 to 14 are schematic views of a battery cell manufacturing method according to an embodiment of the present invention.

Referring to these drawings will be described a battery cell manufacturing method as follows.

First, as shown in FIG. 9, the electrode assembly 110 is mounted on the accommodating part 120 of the battery case 130, and then the battery case 130 is folded in half.

Next, as shown in FIG. 10, in the state in which the electrode assembly 110 is mounted on the accommodating part 120 of the battery case 130, the remaining portions except for one end 150 of the outer circumferential surface of the battery case 130 are heat-sealed. Seal it.

Specifically, the electrode assembly 110 to which the electrode terminals 112 and 114 are connected is mounted in the battery case 130 made of a laminate sheet on which one side 120 is formed. In addition, the three sides, including the upper side including the electrode terminals 112 and 114, the sealing portion 140 is formed on the three sides by thermal compression, the remaining side in the state of the unsealed portion 150 Remains. After injecting the electrolyte through such an unsealed portion 150, as shown in FIG. 11, the end 162 of one corner of the unsealed portion 150 is heat-sealed and charged and discharged to activate the battery cell 100. Let's do it.

Gas and excess electrolyte generated during the activation process is collected in the unsealed portion 150 is collected.

Next, after cutting the unsealed portion 150 inside the end portion to form a through portion 163 communicating with the inside of the battery case 130 as shown in FIG. A vacuum is applied to remove the gas generated during the activation.

Finally, as shown in FIGS. 13 and 14, the inner side 164 of the unsealed portion adjacent to the electrode assembly 110 is heat-sealed by the upper sealing tool and the lower sealing tool, and then the remaining outer portion is cut out to seal the battery cell. Complete 100.

In addition, referring to FIG. 10, the battery case 130 has a rectangular structure in plan view, and the width W of one edge 150 is 200% larger than the width w of the remaining edges.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.

Claims (19)

An apparatus for use in a process of removing gas generated during an activation process of a battery cell in which an electrode assembly and an electrolyte are embedded in a battery case of a laminate sheet including a resin layer and a metal layer.
A vacuum chamber into which a battery cell is inserted;
A jig in which the battery cell is mounted in an inclined state; And
A chamber gate that seals the vacuum chamber and is coupled with a jig;
Degassing device comprising a. The gas removal apparatus according to claim 1, wherein the jig includes a main body portion for mounting one end of the battery cell and a protruding portion with the other end extending upward to mount the battery cell in an inclined state. The gas removal apparatus of claim 2, wherein the protrusion has a height of 10% to 200% based on the height of the main body. 3. The gas removal apparatus according to claim 2, wherein a groove is formed in the body portion in a height direction of the battery cell at a portion corresponding to the end portion for mounting the end portion of the battery cell. The gas removal apparatus of claim 2, wherein an inclined surface is formed at an upper end surface of the protrusion to correspond to an inclination angle of the battery cell. The gas removing apparatus of claim 1, wherein the jig includes a main body on which the battery cells are mounted, and an upper end surface of the main body is an inclined surface on which the battery cells are mounted in an inclined state. The gas removal apparatus according to claim 6, wherein the inclined surface has an inclination angle of 5 degrees to 70 degrees with respect to the horizontal bottom surface of the jig. The gas removal apparatus of claim 1, wherein the chamber gate further includes a gripper for fixing the side sealing end of the battery cell. 9. The gas removal apparatus according to claim 8, wherein the gripper is integrally mounted to the chamber gate. The gas removing apparatus of claim 8, wherein the gripper fixes the side sealing end after the cutter cuts the side sealing end of the battery cell to discharge gas. The gas removing apparatus according to claim 1, wherein the laminate sheet has a laminated structure of an outer resin layer, an air and moisture barrier metal layer, and a heat sealable inner resin layer. The gas removal apparatus of claim 1, wherein the electrode assembly comprises a wound structure, a stacked structure, or a stack / folding structure. A method of manufacturing a battery cell in which an electrode assembly and an electrolyte solution are built into a battery case of a laminate sheet including a resin layer and a metal layer,
(a) injecting the activated battery cell into the vacuum chamber in an inclined state;
(b) fixing the battery cell to a jig located in the vacuum chamber and converting the vacuum chamber into a vacuum;
(c) forming a through part communicating with the inside of the battery case to cut the gas pocket part of the battery cell to discharge the gas inside the battery cell to the outside; And
(d) sealing the inside of the unsealed portion by heat fusion after discharging the gas in the step (c);
And forming a battery cell. The method of claim 13, wherein, prior to step (a),
(a1) heat-sealing the remaining portions of the battery case except one end of the outer circumferential surface of the battery case while the electrode assembly is mounted;
(a2) injecting electrolyte through the unsealed end and sealing the end by heat fusion; And
(a3) activating a battery cell by performing charging and discharging;
Battery cell manufacturing method characterized in that to carry out. 15. The method of claim 14, wherein the battery case has a rectangular structure in plan view, and the one end portion is one edge of the battery case. The method of claim 15, wherein the width of the one corner is 20% to 300% greater than the width of the remaining corners, characterized in that the battery cell manufacturing method characterized in that sealing the end of the one corner in the heat fusion process for activation. The method of claim 13, further comprising, after the step (d), cutting off the remaining outer portion. A battery cell manufactured by the apparatus according to any one of claims 1 to 12. The battery cell according to claim 18, wherein the battery cell is a lithium secondary battery.

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