JP2024069841A - Battery cell and its manufacturing method - Google Patents

Abstract

[Problem] To provide a battery cell with a reduced number of parts and assembly steps, and a manufacturing method thereof. [Solution] The battery cell comprises an electrode assembly including a positive electrode plate and a negative electrode plate, a case body having an opening and housing the electrode assembly, a sealing plate having a terminal insertion hole and sealing the opening of the case body, a terminal that passes through the terminal insertion hole of the sealing plate, a current collector housed in the case body together with the electrode assembly and electrically connected to the positive electrode plate or the negative electrode plate, and a resin insulator including a first portion that insulates the terminal portion and the sealing plate outside the case body, a second portion that insulates the current collector and the sealing plate inside the case body, and a third portion that abuts against the upper end surface of the electrode assembly. The first portion, second portion, and third portion of the resin insulator are integrally molded. [Selected Figure] Figure 6

Description

This technology relates to battery cells and manufacturing methods thereof.

In a battery cell, it has been common practice to provide an insulator between multiple conductive members in order to electrically insulate the multiple conductive parts from each other, as shown in, for example, Patent Document 1.

Patent document 2 describes how roughening is applied to parts of the surface of the lid of the battery case and the electrode terminal of the battery cell to enhance the anchor effect and improve the bonding strength with the insulator.

Chinese Utility Model No. 206742372 JP 2021-086813 A

There is a demand to reduce the number of parts in a battery cell and the labor required to assemble each part during the manufacturing process. From the above perspective, conventional battery cells and manufacturing methods thereof cannot be said to have a sufficient configuration.

The purpose of this technology is to provide a battery cell and a manufacturing method thereof that reduces the number of parts and assembly labor.

This technology provides the following battery cells and manufacturing methods:

[1] A battery cell comprising: an electrode body including a positive electrode plate and a negative electrode plate; a case body having an opening and housing the electrode body; a sealing plate having a terminal insertion hole and sealing the opening of the case body; a terminal portion penetrating the terminal insertion hole of the sealing plate; a current collector housed in the case body together with the electrode body and electrically connected to the positive electrode plate or the negative electrode plate; and a resin insulator including a first portion that insulates the terminal portion and the sealing plate outside the case body, a second portion that insulates the current collector and the sealing plate inside the case body, and a third portion that abuts against the upper end surface of the electrode body, the first portion, second portion, and third portion of the resin insulator being integrally molded.

[2] The battery cell described in [1], in which the terminal portion and the sealing plate each have a contact surface that comes into contact with the resin insulator, and at least one of the terminal portion and the sealing plate has at least a portion of the contact surface roughened.

[3] A battery cell according to [1] or [2], in which the sealing plate has a generally rectangular shape with a short side along a first direction and a long side along a second direction perpendicular to the first direction, and the third portion of the resin insulator abuts against the upper end surface of the electrode body at a first position and a second position spaced apart from each other along the second direction.

[4] The battery cell described in [3], in which the third portion of the resin insulator abuts against the upper end surface of the electrode body at a third position located between the first position and the second position, in addition to the first and second positions.

[5] A method for manufacturing a battery cell, comprising the steps of forming an electrode body including a positive electrode plate and a negative electrode plate, electrically connecting the positive electrode plate or the negative electrode plate to a current collector, attaching a terminal portion and a resin insulator to a sealing plate, connecting the current collector to the terminal portion, housing the electrode body in a case body having an opening, and sealing the opening of the case body with the sealing plate, wherein the resin insulator includes a first portion that insulates the terminal portion from the sealing plate outside the case body, a second portion that insulates the current collector from the sealing plate inside the case body, and a third portion that abuts against the upper end surface of the electrode body, and the first portion, second portion, and third portion of the resin insulator are integrally molded.

[6] The method for manufacturing a battery cell according to [5], further comprising a step of roughening at least a portion of the contact surface of the terminal portion or sealing plate with the resin insulator.

This technology allows the number of parts and assembly steps to be reduced by integrally molding a resin insulator that includes a first portion that insulates the terminal portion and the sealing plate outside the case body, a second portion that insulates the current collector and the sealing plate inside the case body, and a third portion that abuts against the upper end surface of the electrode body.

FIG. 2 is a perspective view showing a battery cell. FIG. 2 is a plan view of a positive electrode plate that constitutes an electrode body. FIG. 2 is a plan view of a negative electrode plate that constitutes an electrode body. FIG. 2 is a plan view showing an electrode assembly consisting of a positive electrode plate and a negative electrode plate. 4A and 4B are diagrams showing a connection structure between an electrode body, a positive electrode current collecting member, and a negative electrode current collecting member. FIG. 2 is a cross-sectional view of a battery cell showing the structures of a terminal portion, a resin insulator, and a current collector. 4 is a cross-sectional view of a sealing plate and a resin insulator in a battery cell. FIG. 11 is a cross-sectional view (part 1) showing a modified example of the structure of the terminal portion and the resin insulator. FIG. 13 is a cross-sectional view (part 2) showing a modified example of the structure of the terminal portion and the resin insulator. FIG. 13 is a cross-sectional view (part 3) showing a modified example of the structure of the terminal portion and the resin insulator. FIG. FIG. 11 is a cross-sectional view (part 4) showing a modified example of the structure of the terminal portion and the resin insulator. 5 is a cross-sectional view showing a modified example of the structure of the terminal portion and the resin insulator; FIG. FIG. 6 is a cross-sectional view showing a modified example of the structure of the terminal portion and the resin insulator; FIG. 11 is a cross-sectional view (part 7) showing a modified example of the structure of the terminal portion and the resin insulator.

The following describes an embodiment of the present technology. Note that the same or corresponding parts are given the same reference symbols, and their descriptions may not be repeated.

In the embodiments described below, when numbers, amounts, etc. are mentioned, the scope of the present technology is not necessarily limited to those numbers, amounts, etc., unless otherwise specified. Furthermore, in the embodiments described below, each component is not necessarily essential to the present technology, unless otherwise specified. Furthermore, the present technology is not necessarily limited to those that achieve all of the effects and advantages mentioned in the present embodiments.

In this specification, the words "comprise," "include," and "have" are open-ended. In other words, when a certain configuration is included, other configurations may or may not be included.

In addition, when geometric terms and terms expressing positional and directional relationships are used in this specification, such as "parallel," "orthogonal," "45° diagonal," "coaxial," and "along," these terms allow for manufacturing errors and slight variations. When terms expressing relative positional relationships, such as "upper side" and "lower side," are used in this specification, these terms are used to indicate the relative positional relationship in one state, and the relative positional relationship can be inverted or rotated to any angle depending on the installation direction of each mechanism (for example, by turning the entire mechanism upside down).

In this specification, a "battery cell" can be installed in a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), an electric vehicle (BEV), etc. However, the use of a "battery cell" is not limited to being installed in a vehicle.

Figure 1 is a perspective view showing a battery cell 100. As shown in Figure 1, the battery cell 100 has a rectangular shape. The battery cell 100 has an electrode terminal 110 (terminal portion), a housing 120 (external can), a gas exhaust valve 130, and a rivet 140.

The electrode terminal 110 is formed on the housing 120. The electrode terminal 110 has a positive electrode terminal 111 and a negative electrode terminal 112 aligned along the X-axis direction (second direction) perpendicular to the Y-axis direction (first direction). The positive electrode terminal 111 and the negative electrode terminal 112 are spaced apart from each other in the X-axis direction.

The housing 120 has a rectangular parallelepiped shape and forms the external appearance of the battery cell 100. The housing 120 includes a case body 120A that contains an electrode body and an electrolyte (not shown), and a sealing plate 120B that seals the opening of the case body 120A. The sealing plate 120B is joined to the case body 120A by welding.

The housing 120 has an upper surface 121, a lower surface 122, a first side surface 123, a second side surface 124, and two third side surfaces 125.

The upper surface 121 is a plane perpendicular to the Z-axis direction (third direction) that is perpendicular to the Y-axis direction and the X-axis direction. The electrode terminal 110 is disposed on the upper surface 121. The lower surface 122 faces the upper surface 121 along the Z-axis direction.

Each of the first side 123 and the second side 124 consists of a plane perpendicular to the Y-axis direction. Each of the first side 123 and the second side 124 has the largest area among the multiple side surfaces of the housing 120. Each of the first side 123 and the second side 124 has a rectangular shape when viewed in the Y-axis direction. Each of the first side 123 and the second side 124 has a rectangular shape with the X-axis direction being the long side direction and the Z-axis direction being the short side direction when viewed in the Y-axis direction.

The multiple battery cells 100 are stacked such that the first side surfaces 123 and the second side surfaces 124 of the adjacent battery cells 100, 100 in the Y-axis direction face each other. As a result, the positive electrode terminals 111 and the negative electrode terminals 112 are arranged alternately in the Y-axis direction in which the multiple battery cells 100 are stacked.

The gas exhaust valve 130 is provided on the top surface 121. When the temperature of the battery cell 100 rises (thermal runaway) and the internal pressure of the housing 120 exceeds a predetermined value due to gas generated inside the housing 120, the gas exhaust valve 130 exhausts the gas to the outside of the housing 120.

The rivet 140 is attached to the sealing plate 120B of the housing 120. The rivet 140 seals the electrolyte injection hole described below.

2 is a plan view of the positive electrode plate 200A constituting the electrode body 200. The positive electrode plate 200A has a main body 220A in which a positive electrode active material mixture layer containing a positive electrode active material (such as lithium nickel cobalt manganese composite oxide), a binder (polyvinylidene fluoride (PVdF)), and a conductive material (such as carbon material) is formed on both sides of a rectangular positive electrode core made of aluminum foil. The positive electrode core protrudes from the end of the main body, and this protruding positive electrode core constitutes the positive electrode tab 210A. A positive electrode protective layer 230A containing alumina particles, a binder, and a conductive material is provided in a portion of the positive electrode tab 210A adjacent to the main body 220A. The positive electrode protective layer 230A has an electrical resistance greater than the electrical resistance of the positive electrode active material mixture layer. The positive electrode active material mixture layer does not need to contain a conductive material. The positive electrode protective layer 230A does not necessarily need to be provided.

Figure 3 is a plan view of the negative electrode plate 200B that constitutes the electrode body 200. The negative electrode plate 200B has a main body 220B in which a negative electrode active material mixture layer is formed on both sides of a rectangular negative electrode core made of copper foil. The negative electrode core protrudes from the edge of the main body 220B, and this protruding negative electrode core constitutes the negative electrode tab 210B.

Figure 4 is a plan view showing an electrode body 200 consisting of positive electrode plates 200A and negative electrode plates 200B. As shown in Figure 5, the electrode body 200 is fabricated so that the positive electrode tabs 210A of each positive electrode plate 200A are stacked at one end, and the negative electrode tabs 210B of each negative electrode plate 200B are stacked. For example, about 50 positive electrode plates 200A and 50 negative electrode plates 200B are stacked. The positive electrode plates 200A and the negative electrode plates 200B are stacked alternately with rectangular separators made of polyolefin interposed between them. Note that a long separator may be folded zigzag.

Figure 5 is a diagram showing the connection structure between the electrode body 200 and the current collector 300 (positive and negative current collectors). As shown in Figure 5, the electrode body 200 is composed of a first electrode body element 201 (first stack group) and a second electrode body element 202 (second stack group). Separators are also arranged on the outer surfaces of the first electrode body element 201 and the second electrode body element 202.

The multiple positive electrode tabs 210A of the first electrode body element 201 constitute the first positive electrode tab group 211A. The multiple negative electrode tabs 210B of the first electrode body element 201 constitute the first negative electrode tab group 211B. The multiple positive electrode tabs 210A of the second electrode body element 202 constitute the second positive electrode tab group 212A. The multiple negative electrode tabs 210B of the second electrode body element 202 constitute the second negative electrode tab group 212B.

The current collector 300 is disposed between the first electrode element 201 and the second electrode element 202. The first positive electrode tab group 211A and the second positive electrode tab group 212A are welded to the positive electrode side current collector 300 to form the welded connection 213. The first negative electrode tab group 211B and the second negative electrode tab group 212B are welded to the negative electrode side current collector 300 to form the welded connection 213. The welded connection 213 can be formed, for example, by ultrasonic welding, resistance welding, laser welding, or the like.

When manufacturing the battery cell 100, the electrode body 200 including the positive electrode plate 200A and the negative electrode plate 200B is formed, and the positive electrode plate 200A and the negative electrode plate 200B are electrically connected to the positive electrode side and the negative electrode side current collector 300, respectively. Next, the positive electrode terminal 111 and the negative electrode terminal 112 (terminal portion) attached to the sealing plate 120B are connected (for example, by crimping) to the positive electrode side and the negative electrode side current collector 300, respectively. In this state, the electrode body 200 is stored in the case body 120A, and the opening of the case body 120A is sealed with the sealing plate 120B.

Figure 6 is a cross-sectional view of the battery cell 100. The structure around the negative terminal 112 will be described using Figure 6. Note that although the structure around the negative terminal 112 will be described below, a similar structure can also be used around the positive terminal 111.

As shown in FIG. 6, the negative electrode terminal 112 includes a terminal board 112A and an external terminal 112B. The terminal board 112A is provided so as to pass through a hole (terminal insertion hole) provided in the sealing plate 120B. The external terminal 112B is provided on the outside of the housing 120 and is connected to the terminal board 112A.

The current collector 300 is housed in the case body 120A together with the electrode body 200. The negative electrode side current collector 300 shown in FIG. 6 is electrically connected to the first negative electrode tab group 211B and the second negative electrode tab group 212B of the negative electrode plate 200B.

The resin insulator 400 includes a first portion 410, a second portion 420, and a third portion 430. The resin insulator 400 is formed, for example, by resin molding. In the resin insulator 400, the first portion 410, the second portion 420, and the third portion 430 are molded integrally.

The first part 410 is located outside the case body 120A. The first part 410 insulates the negative terminal 112 (terminal portion) from the sealing plate 120B.

The second part 420 is located inside the first part and the case body 120A. The second part 420 insulates the current collector 300 from the sealing plate 120B.

The third portion 430 is located inside the case body 120A. The third portion 430 abuts against the upper end surface of the electrode body 200.

Figure 7 is a cross-sectional view of the sealing plate 120B and the resin insulator 400 in the battery cell 100. As shown in Figure 7, the third portion 430 of the resin insulator 400 includes a first boss portion 431, a second boss portion 432, and a third boss portion 433 that are spaced apart from each other along the X-axis direction.

The first boss portion 431 and the second boss portion 432 are provided at both ends of the resin insulator 400 in the X-axis direction (first position and second position). The third boss portion 433 is provided at a midpoint in the X-axis direction (third position) that is different from the both ends of the X-axis direction. More specifically, the third boss portion 433 is provided at the center of the resin insulator 400 in the X-axis direction.

The first boss portion 431, the second boss portion 432, and the third boss portion 433 abut against the upper end surface of the electrode body 200 from the Z-axis direction.

The shape of the resin insulator 400 is not limited to that shown in Figures 6 and 7. For example, the shape of the third portion 430 in the resin insulator 400 (such as the position and number of boss portions) can be changed as appropriate. For example, the base sides of the first boss portion 431, the second boss portion 432, and the third boss portion 433 may be formed thicker than the tip sides.

Next, modified examples of the structure of the negative electrode terminal 112 and the resin insulator 400 will be described using Figures 8 to 14.

In the examples of Figures 8 to 14, at least a portion of the contact surface of the electrode terminal 110 or the sealing plate 120B with the resin insulator 400 is roughened. The roughening is performed, for example, by laser processing of the surface.

In the example of FIG. 8, a roughened portion 112A1 is provided on a portion of the surface of the terminal board 112A, and a roughened portion 120B1 is provided on a portion of the surface of the sealing plate 120B. The roughened portions 112A1 and 120B1 are provided so as to sandwich the second portion 420 of the resin insulator 400.

9 to 11, the roughened portion 120B1 is provided only on a portion of the surface of the sealing plate 120B out of the terminal board 112A and the sealing plate 120B. In the example of FIG. 9, the roughened portion 120B1 is provided on the inner circumferential surface of the terminal insertion hole. In the example of FIG. 10, the roughened portion 120B1 is provided only on the portion that contacts the second portion 420 of the resin insulator 400. In the example of FIG. 11, the roughened portion 120B1 is provided so as to extend in a U-shape from the portion that contacts the first portion 410 of the resin insulator 400 to the inner circumferential surface of the terminal insertion hole and the portion that contacts the second portion 420 of the resin insulator 400.

12 to 14, the roughened portion 112A1 is provided only on a portion of the surface of the terminal board 112A and the sealing plate 120B. In the example of FIG. 12, the roughened portion 112A1 is provided on the outer peripheral surface of the portion inserted into the terminal insertion hole. In the example of FIG. 13, the roughened portion 112A1 is provided only on the portion that contacts the second portion 420 of the resin insulator 400. In the example of FIG. 14, the roughened portion 112A1 is provided so as to extend in an L-shape from the outer peripheral surface of the portion inserted into the terminal insertion hole to the portion that contacts the second portion 420 of the resin insulator 400.

According to the battery cell 100 of this embodiment, the resin insulator including the first part 410 that insulates the electrode terminal 110 and the sealing plate 120B outside the case body 120A, the second part 420 that insulates the current collector 300 and the sealing plate 120B inside the case body 120A, and the third part 430 that abuts the upper end surface of the electrode body 200 is integrally molded. This makes it possible to configure the resin insulator 400, which has conventionally been made up of a combination of multiple parts, as a single part, thereby reducing the number of parts and the labor required to assemble the resin insulator 400.

In addition, if at least a portion of the contact surfaces of the electrode terminal 110 and the sealing plate 120B with the resin insulator 400 is roughened, the adhesion between the electrode terminal 110 and the sealing plate 120B and the resin insulator 400 can be improved due to the anchor effect.

Although the embodiment of the present technology has been described above, the embodiment disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present technology is indicated by the claims, and it is intended to include all modifications within the meaning and scope of the claims.

100 Battery cell, 110 Electrode terminal, 111 Positive electrode terminal, 112 Negative electrode terminal, 112A Terminal plate, 112A1 Roughened portion, 112B External terminal, 120 Housing, 120A Case body, 120B Sealing plate, 120B1 Roughened portion, 121 Upper surface, 122 Lower surface, 123 First side, 124 Second side, 125 Third side, 130 Gas exhaust valve, 140 Rivet, 200 Electrode body, 200A Positive electrode plate, 200B Negative electrode plate, 201 First electrode body element, 202 Second electrode body element, 210A Positive electrode tab, 210B Negative electrode tab, 211A First positive electrode tab group, 211B First negative electrode tab group, 212A Second positive electrode tab group, 212B Second negative electrode tab group, 213 Welded connection part, 220A, 220B main body part, 230A positive electrode protective layer, 300 current collector, 400 resin insulator, 410 first part, 420 second part, 430 third part, 431 first boss part, 432 second boss part, 433 third boss part.

Claims (6)

An electrode assembly including a positive electrode plate and a negative electrode plate;
A case body having an opening and housing the electrode body;
a sealing plate having a terminal insertion hole and sealing an opening of the case body;
a terminal portion that passes through the terminal portion insertion hole of the sealing plate;
a current collector housed in the case body together with the electrode body and electrically connected to the positive electrode plate or the negative electrode plate;
a resin insulator including a first portion that insulates the terminal portion and the sealing plate outside the case body, a second portion that insulates the current collector and the sealing plate inside the case body, and a third portion that abuts on an upper end surface of the electrode assembly,
the first portion, the second portion, and the third portion of the resin insulator are integrally molded. the terminal portion and the sealing plate each have a contact surface that comes into contact with the resin insulating body,
The battery cell according to claim 1 , wherein at least a portion of the contact surface of at least one of the terminal portion and the sealing plate is roughened. the sealing plate has a generally rectangular shape including a short side along a first direction and a long side along a second direction perpendicular to the first direction,
3 . The battery cell according to claim 1 , wherein the third portion of the resin insulator abuts against the upper end surface of the electrode body at a first position and a second position that are spaced apart from each other along the second direction. The battery cell according to claim 3, wherein the third portion of the resin insulator abuts against the upper end surface of the electrode body at a third position located between the first position and the second position, in addition to the first position and the second position. forming an electrode assembly including a positive electrode plate and a negative electrode plate;
a step of electrically connecting the positive electrode plate or the negative electrode plate to a current collector;
a step of attaching a terminal portion and a resin insulator to a sealing plate;
a step of connecting the current collector and the terminal portion;
A step of housing the electrode body in a case body having an opening;
and sealing the opening of the case body with the sealing plate,
the resin insulator includes a first portion that insulates the terminal portion and the sealing plate outside the case body, a second portion that insulates the current collector and the sealing plate inside the case body, and a third portion that abuts on an upper end surface of the electrode body,
The first portion, the second portion, and the third portion of the resin insulator are integrally molded. The method for manufacturing a battery cell according to claim 5 , further comprising the step of roughening at least a part of a contact surface of the terminal portion or the sealing plate with the resin insulator.

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