Title of Invention: Battery cell and its manufacturing method
technology field
[One]
Cross-citation with related application(s)
[2]
This application claims the benefit of priority based on Korean Patent Application No. 10-2020-0122722 dated September 23, 2020, and all contents disclosed in the literature of the Korean patent application are included as part of this specification.
[3]
The present invention relates to a battery cell and a method for manufacturing the same, and more particularly, to a pouch-type battery cell and a method for manufacturing the same.
background art
[4]
Secondary batteries are receiving a lot of attention as energy sources in various product groups such as mobile devices and electric vehicles. These secondary batteries are a powerful energy resource that can replace the use of conventional products that use fossil fuels, and are in the limelight as an eco-friendly energy source because no by-products are generated from energy use.
[5]
Recently, as the need for a high-capacity secondary battery structure has increased, including the use of secondary batteries as an energy storage source, the demand for a multi-module structure battery pack in which a plurality of secondary batteries are connected in series/parallel battery modules is increasing. .
[6]
On the other hand, when a battery pack is configured by connecting a plurality of battery cells in series/parallel, a battery module composed of at least one battery cell is configured, and other components are added using the at least one battery module to form a battery pack. How to configure is common.
[7]
A battery cell inserted into a battery module to be stacked includes an electrode assembly including a positive electrode, a negative electrode, and a separator, and a pouch case having a recessed portion in which the electrode assembly is accommodated.
[8]
In the case of a pouch-type battery cell, a drawing forming shape was applied to form a depression in the pouch case so that the electrode assembly could be inserted using a mold in the pouch case formed of aluminum or thin metal plate. In the process of forming the depression, the battery cell may be formed to be watertight and airtight by bending the pouch case to which drawing forming is applied by 180 degrees and then sealing the outer plane portion.
[9]
At this time, when forming is applied to the pouch case, residual stress may be generated in the peripheral edge portion. In the process of bending the pouch, the residual stress may cause deformation in a form different from the design. This may be called a so-called bat-ear part. In addition, the degree of protrusion to one side through the bat ear can be called edge-long.
[10]
1 is a view showing the state of manufacturing a pouch case of a conventional battery cell.
[11]
Referring to FIG. 1, the manufacturing process of the conventional pouch case will be described in more detail. When the pouch case 20 is manufactured, after forming the recess 21 through forming, the bending line 21a of the pouch case 20 ), the pouch case structure may be completed by bending 180 degrees based on ) to cover the recessed portion 21 . The electrode assembly 10 is inserted into the recessed portion 21 .
[12]
At this time, the bending line 21a of the pouch case 20 may be formed at a portion G spaced apart from the corner line of the recessed portion 21 . Therefore, when the pouch case 20 is bent around the bending line 21a, as shown in FIG. 1, the folded portion of the bending line 21a adjacent to the corner line is not formed smoothly, but the portion protruding outward (P ) can be formed. This can be called a Bat-ear part.
[13]
As a result, when the portion P is bent, residual stress acts near the edge portion, and as shown in FIG. 1 , deformation in a form different from the originally designed pouch shape may occur. The morphological deformation of the portion P may result in various and unnecessary morphological deformations depending on the direction and magnitude of the residual stress.
DETAILED DESCRIPTION OF THE INVENTION
technical challenge
[14]
The problem to be solved by the present invention is to provide a battery cell and a method for manufacturing the same, which prevent morphological deformation of the pouch case due to residual stress.
[15]
The tasks of the present invention are not limited to the tasks mentioned above, and other tasks not mentioned will be clearly understood by those skilled in the art from the following description.
means of solving the problem
[16]
A battery cell according to an embodiment of the present invention for realizing the above object includes an electrode assembly including a positive electrode, a negative electrode, and a separator; and a pouch case formed with a depression in which the electrode assembly is accommodated, wherein the pouch case is bent based on at least one edge line among corners formed by the depression.
[17]
The recessed portion may be recessed in a hexahedral shape, and the pouch case may be bent based on one edge line among 12 corners of the hexahedral shape of the recessed portion.
[18]
The bent pouch case may contact case surfaces to seal the electrode assembly formed inside the recessed portion.
[19]
The pouch case may include aluminum.
[20]
A battery cell according to an embodiment of the present invention for realizing the above object includes a stepped portion and a recessed forming portion, and at least one corner line of the corners of the forming portion forms a stepped line of the stepped portion. In a mold, seating a first bent pouch case based on a bending line corresponding to the step line; Forming the pouch case to have the shape of the forming portion to form a recessed portion; and second bending the pouch case based on the bending line so that case surfaces of the pouch case come into contact with each other.
[21]
The method may further include inserting the electrode assembly into the recess after forming the pouch case to form the recess.
[22]
After the case surfaces of the pouch case are in contact with each other, a step of sealing the contact case surfaces may be further included.
[23]
In the step of forming the recessed part by forming the pouch case, the recessed part may be formed such that the bending line is one of the corners of the recessed part.
[24]
The first bending and the second bending may be bent at 90 degrees, respectively.
[25]
A battery module according to another embodiment of the present invention may include the battery cell.
Effects of the Invention
[26]
A battery cell and a manufacturing method thereof according to an embodiment of the present invention provide an effect of preventing unnecessary case deformation during pouch case manufacturing through a mold and a pouch shape capable of removing a bat ear portion.
[27]
The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.
Brief description of the drawing
[28]
1 is a view showing the state of manufacturing a pouch case of a conventional battery cell.
[29]
2 is a view showing a state in which a pouch case is seated in a mold according to an embodiment of the present invention.
[30]
3 is a view showing how to form a depression in a pouch case according to an embodiment of the present invention.
[31]
4 is a view showing a bent state of the pouch case according to an embodiment of the present invention.
[32]
5 is a view showing a state in which the edge portion of the pouch case is manufactured in a pre-designed form without deformation.
Mode for Carrying Out the Invention
[33]
The embodiments described below are shown by way of example to aid understanding of the invention, and it should be understood that the present invention may be variously modified and implemented differently from the embodiments described herein. However, in the description of the present invention, if it is determined that a detailed description of a related known function or component may unnecessarily obscure the subject matter of the present invention, the detailed description and detailed illustration thereof will be omitted. In addition, the accompanying drawings are not drawn to an actual scale to aid understanding of the present invention, and the dimensions of some components may be exaggerated.
[34]
The first and second terms used in this application may be used to describe various components, but the components should not be limited by the terms. Terms are only used to distinguish one component from another.
[35]
In addition, terms used in this application are only used to describe specific embodiments, and are not intended to limit the scope of rights. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, terms such as "comprise", "consist of" or "consist of" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or It should be understood that it does not preclude the possibility of the presence or addition of more other features, numbers, steps, operations, components, parts, or combinations thereof.
[36]
Hereinafter, a battery cell according to an embodiment of the present invention will be described with reference to FIGS. 2 to 5 .
[37]
2 is a view showing a state in which a pouch case is seated in a mold according to an embodiment of the present invention. 3 is a view showing how to form a depression in a pouch case according to an embodiment of the present invention. 4 is a view showing a bent state of the pouch case according to an embodiment of the present invention. 5 is a view showing a state in which the edge portion of the pouch case is manufactured in a pre-designed form without deformation.
[38]
2 to 5, the battery cell according to an embodiment of the present invention includes an electrode assembly including a positive electrode, a negative electrode, and a separator, and a pouch case 200 having a depression 210 in which the electrode assembly is accommodated. Including, the pouch case 200 is formed by bending based on at least one corner line of the corners formed by the recessed portion 210.
[39]
The electrode assembly is stacked in the order of an anode, a separator, and a cathode, and may be formed in a stack type, jelly roll type, or stack folding type structure, but according to the present embodiment, it may be formed in a rectangular parallelepiped stack type. An electrolyte solution may be inserted into the pouch case 200 , and the electrode assembly may be sealed with the electrolyte solution inside the pouch case 200 . According to this embodiment, the pouch case may be formed of aluminum.
[40]
The depression 210 may be formed on the pouch case 200 . The depression 210 may be formed through a forming process. The recessed portion 210 may be recessed in a hexahedral shape, and the electrode assembly may be inserted into the recessed portion 210 .
[41]
The pouch case 200 may be formed to cover the recessed portion 210 through bending. The bent pouch case 200 may contact case surfaces to seal the electrode assembly formed inside the depression 210 .
[42]
According to this embodiment, the pouch case 200 may be formed by bending based on one of the 12 edges of the hexahedral shape of the depression 210 . Conventionally, the pouch case was bent based on the bending line of the part separated from the corner line of the recessed part, but in this case, the deformation of the shape of the folded part due to the residual stress of the folded part, such as the bat ear part being formed in the folded part of the bent part of the pouch case Therefore, it was difficult to manufacture a pouch cell in the shape of a pre-designed pouch cell.
[43]
Accordingly, according to the present embodiment, the pouch case 200 is bent using the edge line adjacent to the folded portion among the edge lines of the recessed portion as a bending line, thereby minimizing the residual stress of the folded portion and manufacturing the pouch cell in the shape of the pre-designed pouch cell. It is possible to improve the quality of the battery cell and secure productivity.
[44]
Hereinafter, a method for manufacturing a battery cell according to an embodiment of the present invention will be described with reference to FIGS. 2 to 5 .
[45]
Referring to FIGS. 2 to 5 , the method for manufacturing a battery cell according to an embodiment of the present invention includes a stepped portion and a recessed forming portion F shown in FIG. 2 , and the corners of the forming portion F The first bent pouch case 200 is seated on the basis of the bending line 210a corresponding to the stepped line (L) in the mold (M) in which at least one edge line of the stepped portion forms the stepped line (L) of the stepped portion. It includes steps to
[46]
Then, the pouch case 200 shown in FIG. 3 is formed by pressing the forming member A to have the shape of the forming portion F of FIG. 2 to form a depression 210, and The pouch case 200 shown in FIG. 4 is second bent based on the bending line 210a to contact case surfaces of the pouch case 200 with each other.
[47]
In this case, the first bending and the second bending may be bent at 90 degrees, respectively. This is because the angle of the stepped portion is formed at 90 degrees, so that the pouch case 200 can be seated vertically to correspond to the stepped portion with the first bending of 90 degrees toward the mold M, and then an additional 90 degree second bending. Through this, the case surfaces of the pouch case 200 can be completely folded to each other while forming a bending angle of 180 degrees.
[48]
When the pouch type battery cell is manufactured through the above steps, as shown in FIG. 5, the bat ear part P as shown in FIG. 1 is not formed in the bending line 210a of the pouch case 200. can confirm that it is not.
[49]
According to the present embodiment, a step of inserting the electrode assembly 100 into the recessed portion 210 may be further included after the pouch case 200 is formed to form the recessed portion 210 . In addition, after the case surfaces of the pouch case 200 are in contact with each other, a step of sealing the contact case surfaces may be further included.
[50]
Also, in the step of forming the depressed portion 210 by forming the pouch case 200 , the depressed portion 210 may be formed such that the bending line L is one of the corners of the depressed portion 210 . Since the bending line (L) and the corner line of the depression are integrally formed, shape deformation on the folded portion may not occur during a bending process of the pouch case 200 .
[51]
A plurality of the battery cells may be gathered to form a battery module. In addition, a battery pack structure in which a plurality of the battery modules are assembled may be formed.
[52]
The battery pack may have a structure in which one or more of the battery modules are gathered and packed by adding a battery management system (BMS) for managing temperature or voltage of the battery, a cooling device, and the like.
[53]
The battery pack may be applied to various devices. These devices can be applied to means of transportation such as electric bicycles, electric vehicles, hybrid vehicles, etc., but the present invention is not limited thereto and can be applied to various devices capable of using a battery module, which also falls within the scope of the present invention. .
[54]
Although the preferred embodiments of the present invention have been shown and described above, the present invention is not limited to the specific embodiments described above, and is commonly used in the technical field to which the present invention pertains without departing from the gist of the present invention claimed in the claims. Of course, various modifications are possible by those with knowledge of, and these modifications should not be individually understood from the technical spirit or perspective of the present invention.
[55]
explanation of code
[56]
100: electrode assembly
[57]
200: pouch case
[58]
200a: case side
[59]
210: depression
[60]
210a: bending line
[61]
M: mold
[62]
F: forming part
[63]
L: stepped line
[64]
claims
[Claim 1]
An electrode assembly including an anode, a cathode, and a separator; and a pouch case having a recessed portion in which the electrode assembly is accommodated, wherein the pouch case is bent based on at least one edge line among corners formed by the recessed portion.
[Claim 2]
The battery cell of claim 1, wherein the recessed portion is recessed in a hexahedral shape, and the pouch case is bent based on one of the 12 corners of the hexahedral shape of the recessed portion.
[Claim 3]
The battery cell of claim 1, wherein the bent pouch case contacts case surfaces to seal the electrode assembly formed inside the recessed portion.
[Claim 4]
The battery cell of claim 1, wherein the pouch case includes aluminum.
[Claim 5]
A pouch case that is first bent based on a bending line corresponding to the stepped portion in a mold including a stepped portion and a formed portion formed with a depression and at least one corner line of the edges of the forming portion forms a stepped line of the stepped portion settling down; Forming the pouch case to have the shape of the forming portion to form a recessed portion; and second bending the pouch case based on the bending line so that case surfaces of the pouch case come into contact with each other.
[Claim 6]
The method of claim 5, further comprising inserting the electrode assembly into the recess after forming the pouch case to form the recess.
[Claim 7]
The method of claim 5, further comprising sealing the case surfaces in contact with each other after the case surfaces of the pouch case are brought into contact with each other.
[Claim 8]
[Claim 6] The method of claim 5, wherein, in the step of forming the recessed part by forming the pouch case, the recessed part is formed such that the bending line is one of the corners of the recessed part.
[Claim 9]
The method of claim 5, wherein the first bending and the second bending are each bent at 90 degrees.
[Claim 10]
A battery module comprising the battery cell according to claim 1.