Battery cell

Abstract

A battery cell (100) includes a battery element (110), a cover material (120) at least partially covering the battery element (110), and an outer packaging film (140) wrapped around the battery element (110) and the cover material (120). The cover material (120) is defined with a recess (121) engaged with the outer packaging film (140).

Description

Technical Field

[0001] This invention relates to a battery cell. Background Technology

[0002] In recent years, various battery cells have been developed. A battery cell sometimes includes: a battery element; a cover material that at least partially covers the battery element; and an outer film wrapped around the battery element and the cover material.

[0003] Patent Document 1 describes a sealed can-type battery. The sealed can-type battery includes: a metal battery container with an opening, and a metal cap housed in the opening. The cap is partially thinned. The thinned portion of the cap is formed as a safety valve.

[0004] Patent document 2 describes a battery mounting body. The battery mounting body includes: a battery element; and an outer membrane forming a receiving space for housing the battery element. The outer membrane is provided with a package that expands due to increased internal pressure within the receiving space. The package is provided with a safety valve that operates upon expansion of the package.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2001-307705

[0008] Patent Document 2: International Publication No. 2008 / 102571 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] In battery cells that include battery elements, cover materials and outer films, as described in Patent Document 1 or Patent Document 2, a gas release valve is sometimes required.

[0011] One example of the object of the present invention is to form a gas release valve for a battery cell, said battery cell including battery elements, a cover material, and an outer film. Another object of the present invention is apparent from the description herein.

[0012] Technical means to solve the problem

[0013] An embodiment of the present invention is described below.

[0014] 1. A battery cell, comprising:

[0015] Battery components;

[0016] A cover material that at least partially covers the battery element; and

[0017] An outer film is wrapped around the battery element and the cover material.

[0018] The cover material defines a recess that engages with the outer film.

[0019] 2. The battery cell according to 1, wherein,

[0020] The cover material has an edge extending in a specified direction.

[0021] The recess is located approximately at the center of the edge.

[0022] The effects of the invention

[0023] Through the embodiments of the present invention, a gas release valve for a battery cell can be formed, the battery cell including battery elements, a cover material and an outer film. Attached Figure Description

[0024] [ Figure 1 [Illustration 1] is a perspective view showing the battery cell of an embodiment.

[0025] [ Figure 2 ]yes Figure 1 The diagram shows a cross-sectional view of the first virtual surface α.

[0026] [ Figure 3 ]yes Figure 1 A schematic cross-sectional view of the second virtual surface β is shown.

[0027] [ Figure 4 [This is a front view of the first cover material and the first conductor in the first embodiment.]

[0028] [ Figure 5 [This is a front view of the first cover material and the first conductor in the second embodiment.]

[0029] [ Figure 6 [This is a cross-sectional schematic diagram of a portion of the first cover material in the third embodiment.]

[0030] [ Figure 7 [This is a cross-sectional schematic diagram of a portion of the first cover material in the fourth embodiment.] Detailed Implementation

[0031] Hereinafter, embodiments of the present invention will be described using the accompanying drawings. In all the drawings, the same structural elements are labeled with the same reference numerals, and descriptions are appropriately omitted.

[0032] Figure 1 This is a perspective view of the battery unit 100 according to the embodiment. Figure 2 yes Figure 1 The diagram shows a cross-sectional view of the first virtual surface α. Figure 3 yes Figure 1 A schematic cross-sectional view of the second virtual surface β is shown.

[0033] In the figures, the X, Y, and Z directions are shown for illustrative purposes. The X direction represents the front-to-back direction of the battery cell 100. The Y direction is perpendicular to the X direction. The Z direction represents the left-to-right direction of the battery cell 100. The Z direction is perpendicular to both the X and Y directions. The Z direction represents the up-down direction of the battery cell 100. The arrows indicating the X, Y, and Z directions represent the rear, right, and up directions of the battery cell 100, respectively. Figure 2 In the diagram, the white circle with an X-shaped marking indicates the Y-direction, and the arrow pointing in that direction extends from near the front of the paper inwards. Figure 3 In the diagram, the white circle with a black dot representing the Z direction indicates an arrow pointing in the Z direction extending from the inside of the paper towards the front. The relationship between the X, Y, and Z directions and the front-back, left-right, and up-down directions of the battery cell 100 is not limited to the examples described in the embodiment.

[0034] Hereinafter, as needed, the side indicated by the arrow representing the X direction will be referred to as the +X side, and the opposite side will be referred to as the -X side. Hereinafter, as needed, the side indicated by the arrow representing the Y direction will be referred to as the +Y side, and the opposite side will be referred to as the -Y side. Hereinafter, as needed, the side indicated by the arrow representing the Z direction will be referred to as the +Z side, and the opposite side will be referred to as the -Z side.

[0035] Figure 1 and Figure 2 The first virtual surface α shown is a surface perpendicular to the Y direction at approximately the center of the battery cell 100 in the embodiment. Figure 1 and Figure 3 The second virtual surface β shown is a surface perpendicular to the Z direction at approximately the center of the battery cell 100 in the embodiment.

[0036] like Figures 1-3 As shown, the battery cell 100 of the embodiment includes: a plurality of battery elements 110, a pair of cover materials 120, a pair of conductors 130 and an outer film 140.

[0037] like Figure 3 As shown, multiple battery elements 110 overlap each other in the Y direction. Each battery element 110 has a positive electrode, a negative electrode, and a separator (not shown). Figures 1-3 As shown, each battery element 110 is formed into a generally cuboid shape having length in the X direction, width in the Z direction, and height in the Y direction. Viewed from the X direction, each battery element 110 is formed into a generally rectangular shape having a pair of short sides extending along the Y direction and a pair of long sides extending along the Z direction. Figure 2 and Figure 3 As shown, multiple positive current collectors 112 extend from multiple battery elements 110 toward the -X side. The positive terminals of the battery elements 110 and the positive current collectors 112 are electrically connected to each other. Figure 2 and Figure 3 As shown, multiple negative current collectors 114 are led out from multiple battery elements 110 toward the +X side. The negative terminals of the battery elements 110 and the negative current collectors 114 are electrically connected to each other.

[0038] Hereinafter, the battery cell 100 will be described as having a plurality of battery elements 110. However, the number of battery elements 110 included in the battery cell 100 and the shape of each battery element 110 are not limited to [specific details]. Figures 1-3 The example shown. The number of battery elements 110 included in battery cell 100 may be only one, two, three or more.

[0039] like Figure 2 and Figure 3 As shown, a pair of cover materials 120 are located on both sides of a plurality of battery elements 110 in the X direction. Each cover material 120 at least partially covers the plurality of battery elements 110. Each cover material 120 is, for example, an insulator such as resin. Hereinafter, unless otherwise specified, the first cover material 120a and the second cover material 120b refer to the cover material 120 on the -X side and the cover material 120 on the +X side, respectively. The first cover material 120a has a first cover substrate 122a, a first external protrusion 124a, and a first internal protrusion 126a. The second cover material 120b has a second cover substrate 122b, a second external protrusion 124b, and a second internal protrusion 126b. The second cover substrate 122b, the second external protrusion 124b, and the second internal protrusion 126b correspond to the first cover substrate 122a, the first external protrusion 124a, and the first internal protrusion 126a, respectively.

[0040] Reference Figure 2 and Figure 3 The first cover material 120a will be described.

[0041] The first cover substrate 122a is formed in a generally plate-shaped form perpendicular to the X direction. The first cover substrate 122a covers the end faces of the plurality of battery elements 110 on the -X side. Viewed from the X direction, the first cover substrate 122a is formed in a generally rectangular shape having a pair of short sides extending along the Y direction and a pair of long sides extending along the Z direction.

[0042] The first external protrusion 124a is located on the opposite side of the side where the battery element 110 is located, relative to the first cover substrate 122a. The first external protrusion 124a protrudes from the -X side of the surface of the first cover substrate 122a around the X direction. However, the first external protrusion 124a may not be located entirely around the X direction of the first cover substrate 122a, but only partially around the X direction.

[0043] The first internal protrusion 126a is located on one side of the plurality of battery elements 110 relative to the first cover substrate 122a. The first internal protrusion 126a protrudes from the +X side of the face of the first cover substrate 122a around the X direction toward the +X side. However, the first internal protrusion 126a may not be located entirely around the X direction of the first cover substrate 122a, but only partially around the X direction.

[0044] The first cover material 120a and the second cover material 120b are arranged substantially symmetrically, except that the second cover material 120b may be the same as the first cover material 120a.

[0045] like Figure 2 and Figure 3 As shown, a pair of conductors 130 are located on both sides of a plurality of battery elements 110 in the X direction. Each conductor 130 and the plurality of battery elements 110 are electrically connected to each other. Hereinafter, unless otherwise specified, the first conductor 130a and the second conductor 130b refer to the conductor 130 on the -X side and the conductor 130 on the +X side, respectively. The first conductor 130a has a first barrier layer 132a, a first external terminal 134a, and a first internal terminal 136a. The second conductor 130b has a second barrier layer 132b, a second external terminal 134b, and a second internal terminal 136b. The second barrier layer 132b, the second external terminal 134b, and the second internal terminal 136b correspond to the first barrier layer 132a, the first external terminal 134a, and the first internal terminal 136a, respectively.

[0046] Reference Figure 2 and Figure 3 The first conductor 130a will be described.

[0047] The first barrier layer 132a is formed as a layer perpendicular to the X direction. The first barrier layer 132a is, for example, a conductor such as a metal layer. The first cover substrate 122a and the first barrier layer 132a overlap each other at least partially in the X direction. The first barrier layer 132a is at least partially located between the first cover substrate 122a and the plurality of battery elements 110. The water vapor transmission rate of the first barrier layer 132a is less than that of the first cover substrate 122a. Therefore, the first barrier layer 132a can block the transmission of moisture from the first cover material 120a toward the plurality of battery elements 110. The first internal protrusion 126a is at least partially located around the first barrier layer 132a in the X direction. Thus, the first barrier layer 132a can be positioned or held by the first internal protrusion 126a.

[0048] The first external terminal 134a is, for example, a conductor such as a metal block. The first external terminal 134a is located on the opposite side of the side where the plurality of battery elements 110 are located, relative to the first barrier layer 132a. The first external terminal 134a is formed as a protrusion extending from approximately the center of the -X side surface of the first barrier layer 132a toward the -X side. However, the first external terminal 134a may also protrude from a portion of the -X side surface of the first barrier layer 132a that is off-center toward the -X side. The first external terminal 134a penetrates the first cover substrate 122a in the X direction and extends from the -X side surface of the first cover substrate 122a toward the -X side. Thus, the first external terminal 134a can be electrically connected to a conductor such as a busbar (not shown) disposed outside the battery cell 100. In this embodiment, compared to the case where the first conductor 130a does not have the first external terminal 134a, it is easier to electrically connect the first conductor 130a to conductors such as busbars. Therefore, in the implementation, the function of the first conductor 130a can be improved compared to the case where the first conductor 130a does not have the first external terminal 134a.

[0049] In this embodiment, the -X side of the first barrier layer 132a and the +X side of the first external terminal 134a are welded together by welding, such as ultrasonic bonding. Thus, the -X side of the first barrier layer 132a and the +X side of the first external terminal 134a are at least partially joined together. Therefore, the first barrier layer 132a and the first external terminal 134a are electrically connected to each other. However, the joining of the -X side of the first barrier layer 132a and the +X side of the first external terminal 134a is not limited to welding.

[0050] The first internal terminal 136a is, for example, a conductor such as a metal block. The first internal terminal 136a is at least partially located between the first barrier layer 132a and the plurality of battery elements 110. The first internal terminal 136a is formed as a protrusion projecting from approximately the center of the +X side surface of the first barrier layer 132a toward the +X side. However, the first internal terminal 136a may also project from a portion of the +X side surface of the first barrier layer 132a that is offset from approximately the center toward the +X side. The plurality of positive current collectors 112 and the first internal terminal 136a are at least partially joined together by means of laser welding or the like. Thus, the positive electrode of the battery element 110 and the first internal terminal 136a are electrically connected to each other via the positive current collector 112. In this embodiment, compared to the case where the first conductor 130a does not have the first internal terminal 136a, the first conductor 130a and each battery element 110 can be more easily brought closer together in the X direction. Therefore, in this embodiment, compared to the case where the first conductor 130a does not have the first internal terminal 136a, the first conductor 130a and the plurality of positive current collectors 112 can be more easily connected to each other. Therefore, in this embodiment, compared to the case where the first conductor 130a does not have the first internal terminal 136a, the function of the first conductor 130a can be improved.

[0051] In this embodiment, the +X side of the first barrier layer 132a and the -X side of the first internal terminal 136a are welded together by welding, such as ultrasonic bonding. Thus, the +X side of the first barrier layer 132a and the -X side of the first internal terminal 136a are at least partially joined together. Therefore, the first barrier layer 132a and the first internal terminal 136a are electrically connected to each other. However, the joining of the +X side of the first barrier layer 132a and the -X side of the first internal terminal 136a is not limited to welding.

[0052] Regarding the second conductor 130b, the first conductor 130a and the second conductor 130b are arranged in a generally symmetrical manner. The plurality of negative current collectors 114 and the second internal terminal 136b are at least partially joined together by means of laser welding or the like. The first conductor 130a and the second conductor 130b may contain different materials as needed, but may be the same as the first conductor 130a except in this respect.

[0053] The first conductor 130a and the second conductor 130b may contain appropriate materials depending on the polarity of the electrodes electrically connected to the first conductor 130a and the second conductor 130b.

[0054] Regarding the first conductor 130a electrically connected to the positive electrode of the battery element 110, the first barrier layer 132a, the first external terminal 134a, and the first internal terminal 136a may contain at least one of aluminum and aluminum alloys. The first barrier layer 132a, the first external terminal 134a, and the first internal terminal 136a may contain the same material, or they may contain different materials.

[0055] Regarding the second conductor 130b electrically connected to the negative terminal of the battery element 110, the second barrier layer 132b, the second external terminal 134b, and the second internal terminal 136b may contain at least one of copper and copper alloys. The second barrier layer 132b, the second external terminal 134b, and the second internal terminal 136b may contain the same material, or they may contain different materials.

[0056] The second external terminal 134b may also contain a material different from that contained in the second barrier layer 132b and the second internal terminal 136b. For example, while the second barrier layer 132b and the second internal terminal 136b contain at least one of copper and copper alloys, the second external terminal 134b may also contain at least one of aluminum and aluminum alloys. Having at least one of copper and copper alloys in the second barrier layer 132b and the second internal terminal 136b, compared to having at least one of aluminum and aluminum alloys in the second barrier layer 132b and the second internal terminal 136b, allows for a better electrical connection between the negative current collector 114 and the second internal terminal 136b. Similarly, having at least one of aluminum and aluminum alloys in the second external terminal 134b, compared to having at least one of copper and copper alloys in the second external terminal 134b, allows for a better electrical connection between the conductors such as the busbar outside the battery cell 100 and the second external terminal 134b.

[0057] An outer film 140 is wound around the battery element 110 and a pair of cover materials 120 in the X direction. The outer film 140 is, for example, a laminated film.

[0058] like Figure 2 and Figure 3 As shown, the outer peripheral surface of the first cover substrate 122a surrounding the X direction and the outer film 140 are at least partially joined together by means of bonding, such as heat fusion. Figure 2 and Figure 3 As shown, the outer peripheral surface of the first outer protrusion 124a surrounding the X direction and the inner peripheral surface of the outer film 140 in the portion of the first outer protrusion 124a surrounding the X direction are at least partially joined together by means of, for example, heat fusion. Figure 2 and Figure 3As shown, the outer peripheral surface of the first inner protrusion 126a surrounding the X direction and the inner peripheral surface of the outer film 140 surrounding the X direction of the first inner protrusion 126a are at least partially joined together by means of bonding, such as heat welding. Thus, the battery cell 100 has a -X-side sealing portion formed by the -X-side ends of the first cover material 120a and the outer film 140. The battery cell 100 also has a +X-side sealing portion formed similarly to the -X-side sealing portion by means of the +X-side ends of the second cover material 120b and the outer film 140. The battery cell 100 also has another sealing portion extending along the X direction, spanning from one of the sealing portions on both sides of the X direction to the other. For example, when the outer film 140 is wrapped around the battery element 110 and the pair of cover materials 120 in the X direction, the excess length of the outer film 140 extending from the wrapped portion of the battery element 110 and the pair of cover materials 120 is joined to each other by means of, for example, heat welding, thereby forming another sealing portion.

[0059] A pair of cover materials 120 and an outer film 140 form a receiving space for accommodating a plurality of battery elements 110. The receiving space is sealed by sealing portions on both sides of the battery cell 100 in the X direction, and by another sealing portion extending from one side of the sealing portions on both sides of the battery cell 100 in the X direction across the other. In this embodiment, the electrolyte and the plurality of battery elements 110 are contained together in the receiving space.

[0060] exist Figure 2 and Figure 3 In the example shown, the first conductor 130a defines an aperture 131. The aperture 131 penetrates the first barrier layer 132a, the first external terminal 134a, and the first internal terminal 136a in the X direction. For illustration, in... Figure 1 Hole 131 is not shown in the figure. Viewed from the X direction, hole 131 is located approximately at the center of the first conductor 130a. However, when viewed from the X direction, hole 131 may also exist off-center from the first conductor 130a. Hole 131 is formed as an injection port for injecting electrolyte into the receiving space formed by a pair of cover materials 120 and an outer film 140.

[0061] like Figure 2 and Figure 3As shown, a plug 138 is embedded in the hole 131. Thus, the hole 131 is blocked by the plug 138. Therefore, the hole 131 can be sealed by the plug 138. The plug 138 is, for example, metal. In an embodiment, the inner circumferential surface of the hole 131 of the first conductor 130a around the X direction is welded to the outer circumferential surface of the plug 138 around the X direction. Therefore, the structure of the hole 131 is simpler compared to screwing the plug 138 into the hole 131. When the plug 138 is screwed into the hole 131, resin is sometimes needed to fill the space between the hole 131 and the plug 138. In contrast, in this embodiment, resin is not filled between the hole 131 and the plug 138, and the hole 131 can be sealed by the plug 138. However, the plug 138 can also be a screw that can be screwed into the hole 131.

[0062] exist Figure 2 and Figure 3 In the example shown, the plug 138 is at least partially located inside the first external terminal 134a. Therefore, compared to the case where the plug 138 is located inside the first barrier layer 132a or the first internal terminal 136a, the inner circumferential surface of the hole 131 of the conductor 130 around the X direction and the outer circumferential surface of the plug 138 around the X direction can be more easily soldered together. However, the plug 138 may also be at least partially located inside the first barrier layer 132a or the first internal terminal 136a.

[0063] exist Figure 2 and Figure 3 In the example shown, hole 131 and plug 138 are provided in the first conductor 130a. However, hole 131 and plug 138 may also be provided in the second conductor 130b instead of the first conductor 130a.

[0064] Reference Figure 2 and Figure 3 The -X side ends of the first cover material 120a, the first conductor 130a, and the outer film 140 in the embodiment will be further described. The matters described below regarding the -X side ends of the first cover material 120a, the first conductor 130a, and the outer film 140 can also be applied to the +X side ends of the second cover material 120b, the second conductor 130b, and the outer film 140.

[0065] In this embodiment, heat applied by a sealing strip (not shown) from the inner peripheral surface of the first outer protrusion 124a in the X-direction and the outer peripheral surface of the outer film 140 in the X-direction portion of the first outer protrusion 124a causes at least partial thermal fusion between the outer peripheral surface of the first outer protrusion 124a in the X-direction and the inner peripheral surface of the outer film 140 in the X-direction portion of the first outer protrusion 124a. Therefore, compared to the case where the first cover material 120a does not have the first outer protrusion 124a, the ends of the first cover material 120a and the outer film 140 on the X-side can be more easily thermally fused together. Furthermore, compared to the case where the first cover material 120a does not have the first outer protrusion 124a, the bonding area between the first cover material 120a and the outer film 140 can be increased. Therefore, compared with the case where the first cover material 120a does not have the first external protrusion 124a, the bonding strength of the ends of the first cover material 120a and the outer film 140 on the -X side can be improved, and the sealing performance of the sealing portion on the -X side of the battery cell 100 can be improved.

[0066] In this embodiment, as described above, heat is applied to the inner peripheral surface of the first outer protrusion 124a surrounding the X direction and the outer peripheral surface of the outer film 140 surrounding the X direction of the first outer protrusion 124a. A portion of this heat is also conducted to the first inner protrusion 126a and the area surrounding the first inner protrusion 126a of the outer film 140 in the X direction. Thus, through this heat, the outer peripheral surface of the first inner protrusion 126a surrounding the X direction and the inner peripheral surface of the outer film 140 surrounding the X direction of the first inner protrusion 126a can be at least partially thermally fused together.

[0067] In this embodiment, compared to the case where the first cover material 120a does not have the first internal protrusion 126a, the bonding area between the first cover material 120a and the outer film 140 can be increased by an amount corresponding to the first internal protrusion 126a. Assuming that the bonding area between the first cover material 120a and the outer film 140 is ensured by the first external protrusion 124a when the first cover material 120a does not have the first internal protrusion 126a, the dimension of the first external protrusion 124a in the X direction becomes relatively large, sometimes making it difficult to miniaturize the battery cell 100 in the X direction. In contrast, in this embodiment, the bonding area on the -X side of the first cover material 120a and the outer film 140 can be ensured by both the first external protrusion 124a and the first internal protrusion 126a. Therefore, in this embodiment, compared to the case where the first cover material 120a does not have the first internal protrusion 126a, the dimension of the first external protrusion 124a in the X direction can be reduced, allowing for miniaturization of the battery cell 100 in the X direction. Therefore, in this embodiment, compared to the case where the first cover material 120a does not have the first internal protrusion 126a, the sealing performance of the sealing portion on the -X side of the battery cell 100 and the miniaturization of the battery cell 100 in the X direction can be achieved at the same time.

[0068] exist Figure 2 and Figure 3 In the example shown, the dimension in the X direction of the first inner protrusion 126a spanning from the -X side to the +X side is smaller than the dimension in the X direction of the first outer protrusion 124a spanning from the +X side to the -X side. Figure 2 and Figure 3 In the example shown, the dimension in the X direction of the first internal protrusion 126a is the distance in the X direction between the +X side surface of the first cover substrate 122a and the +X side end face of the first internal protrusion 126a. Figure 2 and Figure 3 In the example shown, the dimension in the X direction of the first external protrusion 124a is the distance in the X direction between the -X side surface of the first cover substrate 122a and the -X side end face of the first external protrusion 124a. As described above, in the embodiment, a portion of the heat applied from the inner peripheral surface of the first external protrusion 124a around the X direction and the outer peripheral surface of the outer film 140 of the portion of the first external protrusion 124a around the X direction is conducted to the first internal protrusion 126a and the portion of the first internal protrusion 126a around the X direction corresponding to the outer film 140. Therefore, in Figure 2 and Figure 3 In the example shown, compared to the case where the dimension of the first internal protrusion 126a in the X direction is greater than or equal to the dimension of the first external protrusion 124a in the X direction, more heat can be more easily transferred to the first internal protrusion 126a and the portion of the first internal protrusion 126a surrounding the X direction corresponding to the outer membrane 140. Therefore, in Figure 2 and Figure 3 In the example shown, compared to the case where the dimension in the X direction of the first inner protrusion 126a is greater than or equal to the dimension in the X direction of the first outer protrusion 124a, the bonding strength between the ends of the first inner protrusion 126a and the outer film 140 on the -X side can be improved. However, the dimension in the X direction of the first inner protrusion 126a may also be greater than or equal to the dimension in the X direction of the first outer protrusion 124a.

[0069] exist Figure 2 and Figure 3In the example shown, the first internal terminal 136a is located closer to the side where the plurality of battery elements 110 are located than the first internal protrusion 126a. That is, the +X side end face of the first internal terminal 136a is more biased towards the +X side than the +X side end face of the first internal protrusion 126a. Therefore, compared to the case where the +X side end faces of the first internal terminal 136a and the first internal protrusion 126a are coplanar, the positive current collector 112 and the first internal protrusion 126a are less likely to interfere with each other. Therefore, compared to the case where the positive current collector 112 and the first internal protrusion 126a interfere with each other, the output of the battery cell 100 can be stabilized. Therefore, compared to the case where the +X side end faces of the first internal terminal 136a and the +X side end faces of the first internal protrusion 126a are coplanar, both the sealing performance of the sealing portion on the -X side of the battery cell 100 and the output stabilization of the battery cell 100 can be achieved. However, the +X side end face of the first internal terminal 136a and the +X side end face of the first internal protrusion 126a may also be coplanar. Alternatively, the +X side end face of the first internal terminal 136a may be more biased towards the -X side than the +X side end face of the first internal protrusion 126a.

[0070] Figure 4 This is a front view of the first cover material 120a and the first conductor 130a in the first embodiment. Figure 4 In the middle, the white circle with an X indicates the X direction, and the arrow indicating the X direction extends from the front of the paper toward the inside.

[0071] like Figure 4 As shown, the first cover 120a defines a recess 121. The recess 121 may extend through the first cover 120a from one end on the -X side to the other end on the +X side, or it may partially extend from one end on the -X side to the other end on the +X side. The outer peripheral surface of the first cover 120a, including the recess 121, in the X direction, and the inner peripheral surface of the outer film 140 in the X direction are joined together by means of heat fusion or the like. Inside the receiving space formed by the pair of cover materials 120 and the outer film 140, gas may sometimes be generated from the battery element 110 due to an abnormality. Due to this gas, the internal pressure of the receiving space may sometimes increase. Due to the increase in internal pressure within the containment space, stress is generated in the first cover 120a and the outer membrane 140, causing the outer peripheral surface of the first cover 120a around the X direction to peel away from the inner peripheral surface of the outer membrane 140 around the X direction. Figure 4 In the example shown, due to the shape of the recess 121, this stress tends to concentrate in the recess 121. Therefore, in Figure 4In the example shown, when the internal pressure of the containment space increases, the outer peripheral surface of the first cover 120a around the X direction and the inner peripheral surface of the outer film 140 around the X direction are more easily peeled off at the recess 121 than at the portion different from the recess 121. Therefore, the portion where the first cover 120a and the outer film 140 are joined together at the recess 121 can function as a gas release valve when the internal pressure of the containment space increases.

[0072] exist Figure 4 In the example shown, viewed from the X direction, the recess 121 is located approximately at the center of the short side of the first cover 120a on the +Z side in the Y direction. Therefore, compared to the case where the recess 121 is offset in the Y direction from the approximately center of the short side of the first cover 120a on the +Z side, stress is more likely to concentrate in the recess 121 when the internal pressure of the receiving space increases. Consequently, compared to the case where the recess 121 is offset in the Y direction from the approximately center of the short side of the first cover 120a on the +Z side, the portion where the first cover 120a and the outer membrane 140 meet at the recess 121 is more likely to function as a gas release valve. However, viewed from the X direction, the recess 121 may also be offset in the Y direction from the approximately center of the short side of the first cover 120a on the +Z side. Viewed from the X direction, the recess 121 may replace the short side located on the +Z side of the first cover material 120a, or it may also be located on the -Z side of the first cover material 120a. The number of recesses 121 on each side may be only one, or there may be more than two.

[0073] In some embodiments, multiple battery cells 100 are arranged in the Y direction. When multiple battery cells 100 are arranged in the Y direction, the side of the recess 121 located on the +Z side or -Z side of the first cover material 120a is less likely to conduct gas discharged from the recess 121 to other battery cells 100 compared to the side of the recess 121 located on the +Y side or -Y side of the first cover material 120a, thus suppressing the influence of gas discharged from the recess 121 on other battery cells 100.

[0074] Figure 5 This is a front view of the first cover material 120a and the first conductor 130a in the second embodiment. Figure 5 The second example shown, except for the following aspects, is similar to Figure 4 The first example shown is the same.

[0075] like Figure 5 As shown, viewed from the X direction, the recess 121 can also be located approximately at the center of the long side of the first cover material 120a on the -Y side in the Z direction. Figure 5In the example shown, the portion where the first cover 120a and the outer membrane 140 meet at the recess 121 can also function as a gas release valve when the internal pressure of the containment space rises. Furthermore, compared to the case where the recess 121 is offset in the Z direction from approximately the center of the long side of the -Y side of the first cover 120a in the Z direction, the portion where the first cover 120a and the outer membrane 140 meet at the recess 121 is more likely to function as a gas release valve. However, viewed from the X direction, the recess 121 can also be offset in the Z direction from approximately the center of the long side of the -Y side of the first cover 120a in the Z direction. Viewed from the X direction, the recess 121 can also replace the long side of the first cover 120a located on the -Y side, or in addition, be located on the long side of the first cover 120a on the +Y side. The number of recesses 121 located on each side can be only one, or it can be two or more.

[0076] The location of the recess 121 is not limited to... Figure 4 and Figure 5 As shown in the example. Viewed from the X direction, the recess 121 may also be located on two intersecting sides of the first cover material 120a, on three sides, or on all four sides. Viewed from the X direction, the recess 121 may also be located at at least one of the four corners of the first cover material 120a.

[0077] Figure 6 This is a cross-sectional schematic diagram of a portion of the first cover material 120a in the third embodiment. Figure 6 The third example shown, in addition to the following aspects, is similar to Figure 4 The first example shown is the same.

[0078] like Figure 6 As shown, the recess 121 may also partially extend from one end of the first cover material 120a on the -X side to the other end of the first cover material 120a on the +X side. Figure 6 In the example shown, the recess 121 extends from the +X side end face of the first inner protrusion 126a across the +X side end face of the first outer protrusion 124a. Figure 6 In the example shown, the dimension of the recess 121 in the Y direction decreases as it moves toward the -X side. Figure 6 In the example shown, viewed from the Z direction, the Y-side surface of the first cover material 120a with the recess 121 is formed in a straight line. Figure 6 In the example shown, the portion where the first cover 120a and the outer membrane 140 meet at the recess 121 can also function as a gas release valve when the internal pressure of the containment space rises.

[0079] Figure 7 This is a cross-sectional schematic diagram of a portion of the first cover material 120a in the fourth embodiment. Figure 7 The fourth example shown, except for the following aspects, is similar to Figure 6 The third example shown is the same.

[0080] like Figure 7 As shown, viewed from the Z direction, the surface of the first cover material 120a on the -Y side where the recess 121 is formed can also be formed in a curved shape. Figure 7 In the example shown, the portion where the first cover 120a and the outer membrane 140 meet at the recess 121 can also function as a gas release valve when the internal pressure of the containment space rises.

[0081] The embodiments of the present invention have been described above with reference to the accompanying drawings, but these are merely examples of the present invention, and various other structures may also be employed.

[0082] This application claims priority based on Japanese Patent Application No. 2024-012108, filed on January 30, 2024, and incorporates the entire contents of that application.

[0083] Explanation of icon numbers

[0084] 100: Battery cell

[0085] 110: Battery components

[0086] 112: Positive current collector

[0087] 114: Negative current collector

[0088] 120: Cover Material

[0089] 120a: First cover material

[0090] 120b: Second cover material

[0091] 121: concave part

[0092] 122a: First cover substrate

[0093] 122b: Second cover substrate

[0094] 124a: First external protrusion

[0095] 124b: Second external protrusion

[0096] 126a: First internal protrusion

[0097] 126b: Second internal protrusion

[0098] 130: Conductor

[0099] 130a: First conductor

[0100] 130b: Second conductor

[0101] 131: Kong

[0102] 132a: First barrier layer

[0103] 132b: Second barrier layer

[0104] 134a: First external terminal

[0105] 134b: Second external terminal

[0106] 136a: First internal terminal

[0107] 136b: Second internal terminal

[0108] 138: Stopper

[0109] 140: Exterior film

Claims

1. A battery cell, comprising: Battery components; A cover material that at least partially covers the battery element; as well as An outer film is wrapped around the battery element and the cover material. The cover material defines a recess that engages with the outer film.

2. The battery cell according to claim 1, wherein, The cover material has an edge extending in a specified direction. The recess is located approximately at the center of the edge.

Images