Battery cell

Abstract

To improve a function of a battery cell.SOLUTION: A battery cell 100 comprises: a battery element 110; an outer casing film 140 that is wound to the battery element 110; and a spacer 150 that is at least partially positioned between the battery element 110 and the outer casing film 140.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a battery cell.

Background Art

[0002] In recent years, various battery cells have been developed. A battery cell includes a battery element and an exterior material that seals the battery element.

[0003] Patent Document 1 describes a battery module. The battery module includes a plurality of single cells, and an upper holding member and a lower holding member that are located on both sides of the plurality of single cells in the stacking direction of the plurality of single cells. An adhesive portion is adhered between the uppermost single cell of the plurality of single cells and the upper holding member, and another adhesive portion is adhered between the lowermost single cell of the plurality of single cells and the lower holding member.

[0004] Patent Document 2 describes a film exterior battery. The film exterior battery includes a film exterior material. A solid barrier material is provided on the inner surface of the end portion where the positive electrode terminal and the negative electrode terminal of the film exterior material are drawn out.

[0005] Patent Document 3 describes a lithium ion secondary battery. The lithium ion secondary battery includes a battery element, a battery can that houses the battery element, and a sealing plate provided at the upper end opening of the battery can. A foamed resin sheet is disposed between the lower portion of the battery element and the battery can. Another foamed resin sheet is disposed between the upper portion of the battery element and the sealing plate.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] In a battery cell, an exterior film may be wound around a battery element. A battery cell having an exterior film wound around a battery element may be required to have certain functions.

[0008] An example of the object of the present invention is to improve the function of a battery cell. Other objects of the present invention will become apparent from the description herein.

MEANS FOR SOLVING THE PROBLEMS

[0009] One aspect of the present invention is as follows. 1. A battery element, an exterior film wound around the battery element, and a spacer at least partially located between the battery element and the exterior film, A battery cell comprising: 2. Further comprising a terminal electrically connected to the battery element, The battery element has a shape having a longitudinal direction and a short-side direction perpendicular to the direction from the side where the battery element is located to the side where the terminal is located, The battery cell according to 1., wherein at least a part of the spacer is located on at least one of both sides in the longitudinal direction of the battery element. 3. The battery cell according to 1. or 2., wherein the battery element and the exterior film are physically joined to each other via the spacer. 4. The battery cell according to any one of 1. to 3., wherein the battery element and the exterior film are thermally bonded to each other via the spacer. 5. The battery cell according to any one of 1. to 4., wherein a plurality of the battery elements are physically joined to each other via the spacer. 6. The battery cell according to any one of 1. to 5., wherein the spacer contains an adhesive at least partially.

Advantages of the Invention

[0010] According to the above aspect of the present invention, the function of the battery cell can be improved.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same components are denoted by the same reference numerals, and the description will be omitted as appropriate.

[0013] FIG. 1 is a perspective view of a battery cell 100 according to an embodiment. FIG. 2 is a side view of the battery cell 100 according to the embodiment with the outer film 140 removed. FIG. 3 is a schematic cross-sectional view of the virtual plane α shown in FIG. 1.

[0014] In each figure, for the purpose of explanation, the X direction, Y direction, and Z direction are shown. The X direction indicates the front-rear direction of the battery cell 100. The Y direction is a direction perpendicular to the X direction. The Y direction indicates the left-right direction of the battery cell 100. The Z direction is a direction perpendicular to both the X direction and the Y direction. The Z direction indicates the up-down direction of the battery cell 100. The arrow indicating the X direction, the arrow indicating the Y direction, and the arrow indicating the Z direction indicate the rear direction, the right direction, and the up direction of the battery cell 100, respectively. In FIG. 2, the white circle with X indicating the Y direction indicates that the arrow indicating the Y direction extends from the front to the back of the paper surface. In FIG. 3, the white circle with X indicating the X direction indicates that the arrow indicating the X direction extends from the front to the back of the paper surface. The relationship between the X direction, Y direction, and Z direction and the front-rear direction, left-right direction, and up-down direction of the battery cell 100 is not limited to the example of the description according to the embodiment.

[0015] Hereinafter, as necessary, the side indicated by the arrow indicating the X direction is referred to as the +X side, and the opposite side of the side indicated by the arrow indicating the X direction is referred to as the -X side. Hereinafter, as necessary, the side indicated by the arrow indicating the Y direction is referred to as the +Y side, and the opposite side of the side indicated by the arrow indicating the Y direction is referred to as the -Y side. Hereinafter, as necessary, the side indicated by the arrow indicating the Z direction is referred to as the +Z side, and the opposite side of the side indicated by the arrow indicating the Z direction is referred to as the -Z side.

[0016] The virtual plane α shown in FIGS. 1 and 3 is a plane perpendicular to the X direction at the substantially central portion in the X direction of the battery cell 100 according to the embodiment. For the purpose of explanation, the dimensional ratio of the Y direction with respect to the Z direction of the battery cell 100 shown in FIG. 3 is larger than the dimensional ratio of the Y direction with respect to the Z direction of the battery cell 100 shown in FIG. 1.

[0017] As shown in FIGS. 1 to 3, the battery cell 100 according to the embodiment includes a plurality of battery elements 110, a pair of terminals 120, a pair of lid materials 130, an exterior film 140, and a spacer 150.

[0018] In the example shown in FIG. 3, a plurality of battery elements 110 overlap each other in the Y direction. Hereinafter, as necessary, the plurality of battery elements 110 that overlap each other in the Y direction are integrally referred to as a laminate 110G. Each battery element 110 has a substantially rectangular parallelepiped shape. Specifically, when viewed from the X direction, each battery element 110 has a shape having a longitudinal direction and a short-side direction perpendicular to the X direction. When viewed from the X direction, the longitudinal direction of each battery element 110 is oriented in the Z direction. When viewed from the X direction, the short-side direction of each battery element 110 is oriented in the Y direction. In the examples shown in FIGS. 1 and 3, when viewed from the X direction, the laminate 110G has a shape having a longitudinal direction and a short-side direction perpendicular to the X direction, similar to each battery element 110. The number of battery elements 110 included in the battery cell 100 is not limited to the example shown in FIG. 3. For example, the battery cell 100 may include only one battery element 110, two battery elements 110, or four or more battery elements 110.

[0019] As shown in FIG. 3, each battery element 110 has a plurality of positive electrodes 112, a plurality of negative electrodes 114, and a separator 116. In each battery element 110, the plurality of positive electrodes 112 and the plurality of negative electrodes 114 are alternately arranged in the Y direction. The area of each negative electrode 114 perpendicular to the Y direction is larger than the area of each positive electrode 112 perpendicular to the Y direction. In the example shown in FIG. 3, the dimension of each negative electrode 114 in the Z direction is larger than the dimension of each positive electrode 112 in the Z direction. As shown in FIG. 3, when viewed from the X direction, the separator 116 includes a zigzag portion 116a and an enclosing portion 116b. When viewed from the X direction, the zigzag portion 116a is alternately folded back by a folded-back portion on the +Z side of the zigzag portion 116a and a folded-back portion on the -Z side of the zigzag portion 116a. When viewed from the X direction, in a state where the folded-back portion on the +Z side of the zigzag portion 116a covers the end portion on the +Z side of the positive electrode 112 and the folded-back portion on the -Z side of the zigzag portion 116a covers the end portion on the -Z side of the negative electrode 114, the positive electrode 112 and the negative electrode 114 adjacent to each other in the Y direction are separated from each other. When viewed from the X direction, the enclosing portion 116b surrounds the positive electrodes 112 and the negative electrodes 114 that are alternately arranged in the Y direction and the zigzag portion 116a.

[0020] The structure of the separator 116 is not limited to the structure shown in FIG. 3. For example, the separator 116 may not include the surrounding portion 116b and may include only the zigzag portion 116a. Alternatively, instead of the separator 116 shown in FIG. 3, the battery element 110 may include a plurality of separators 116 having a substantially sheet shape perpendicular to the Y direction. When the battery element 110 includes a plurality of separators 116 having a substantially sheet shape perpendicular to the Y direction, the plurality of positive electrodes 112, the plurality of negative electrodes 114, and the plurality of separators 116 overlap in the Y direction with each separator 116 separating the adjacent positive electrode 112 and negative electrode 114 in the Y direction. Alternatively, the positive electrode 112, the negative electrode 114, and the separator 116 may be wound such that the separator 116 is disposed between the positive electrode 112 and the negative electrode 114. In one example, the positive electrode 112, the negative electrode 114, and the separator 116 are wound with one of the two surfaces of the positive electrode 112 and the negative electrode 114 covered by the separator 116. In another example, a laminate including a plurality of unit laminates including the positive electrode 112, the separator 116, and the negative electrode 114 in this order may be wound. However, the winding structure of the positive electrode 112, the negative electrode 114, and the separator 116 is not limited to these examples.

[0021] As shown in FIG. 2, a pair of terminals 120 are located on both sides of the laminate 110G in the X direction. The terminal 120 on the -X side and the positive electrode 112 of the laminate 110G are electrically connected to each other via the positive electrode current collector 112a drawn out. Therefore, in the embodiment, the terminal 120 on the -X side serves as the positive electrode terminal. The positive electrode current collector 112a is drawn out from the laminate 110G toward the -X side. In one example, the positive electrode current collector 112a is integral with the positive electrode current collector constituting the positive electrode 112. The terminal 120 on the +X side and the negative electrode 114 of the laminate 110G are electrically connected to each other via the negative electrode current collector 114a drawn out. Therefore, in the embodiment, the terminal 120 on the +X side serves as the negative electrode terminal. The negative electrode current collector 114a is drawn out from the laminate 110G toward the +X side. In one example, the negative electrode current collector 114a is integral with the negative electrode current collector constituting the negative electrode 114. The terminal 120 on the -X side may serve as the negative electrode terminal, and the terminal 120 on the +X side may serve as the positive electrode terminal.

[0022] As shown in FIG. 2, the pair of lid members 130 are located on both sides of the laminate 110G in the X direction. Each lid member 130 is, for example, a resin body. As shown in FIG. 1, when viewed from the X direction, each lid member 130 has a substantially rectangular shape having a pair of short sides parallel to the Y direction and a pair of long sides parallel to the Z direction. The terminal 120 on the -X side protrudes at least partially toward the -X side from the -X side surface of the -X side lid member 130 with the -X side lid member 130 covering the -X side end face of the laminate 110G. The terminal 120 on the +X side protrudes at least partially toward the +X side from the +X side surface of the +X side lid member 130 with the +X side lid member 130 covering the +X side end face of the laminate 110G.

[0023] In the embodiment, the exterior film 140 is a flexible laminate film. As shown in FIGS. 1 and 3, the exterior film 140 has a winding portion 142 and a drawing portion 144. The winding portion 142 is wound around the laminate 110G and the pair of lid members 130 in the X direction. The outer peripheral surface of the -X side lid member 130 around the X direction and the inner peripheral surface of the -X side end of the winding portion 142 around the X direction are joined to each other by a joining method such as heat fusion. Therefore, a sealing portion is formed by the -X side lid member 130 and the -X side end of the winding portion 142. The outer peripheral surface of the +X side lid member 130 around the X direction and the inner peripheral surface of the +X side end of the winding portion 142 around the X direction are joined to each other by a joining method such as heat fusion. Therefore, a sealing portion is formed by the +X side lid member 130 and the +X side end of the winding portion 142. As shown in FIG. 3, the drawing portion 144 includes a first drawing portion 144a and a second drawing portion 144b. The first drawing portion 144a is drawn from one end of the winding portion 142 around the X direction, and the second drawing portion 144b is drawn from the other end of the winding portion 142 around the X direction. The surfaces of the first drawing portion 144a and the second drawing portion 144b that contact each other are joined to each other by a joining method such as heat fusion. Therefore, a sealing portion is formed by the first drawing portion 144a and the second drawing portion 144b. In the example shown in FIGS. 1 and 3, when viewed from the X direction, the drawing portion 144 is drawn from the +Y side and +Z side corner portions of the laminate 110G and bent toward the outer surface of the +Z side of the winding portion 142. However, the way the drawing portion 144 is drawn is not limited to the example shown in FIGS. 1 and 3.

[0024] In the battery cell 100 according to the embodiment, the pair of lid materials 130 and the exterior film 140 seal a space surrounded by the winding portion 142 between the pair of lid materials 130. Inside the space sealed by the pair of lid materials 130 and the exterior film 140, the laminate 110G is located. The battery cell 100 according to the embodiment contains an electrolytic solution inside the space sealed by the pair of lid materials 130 and the exterior film 140. However, the battery cell 100 may be an all-solid-state battery. In the all-solid-state battery, a solid electrolyte layer is provided in a portion corresponding to the separator 116. The all-solid-state battery does not contain an electrolytic solution. Hereinafter, unless otherwise specified, the battery cell 100 will be described as a battery cell containing an electrolytic solution.

[0025] As shown in FIGS. 2 and 3, the spacer 150 is located between the outer surface of the laminate 110G on the -Z side and the inner surface on the +Z side of the portion covering the outer surface of the laminate 110G on the -Z side of the winding portion 142. Therefore, the spacer 150 is at least partially located between the laminate 110G and the exterior film 140. Hereinafter, as necessary, the outer surface of the laminate 110G on the -Z side will be referred to as the outer bottom surface of the laminate 110G, the portion covering the outer bottom surface of the laminate 110G of the winding portion 142 will be referred to as the bottom of the winding portion 142, and the surface on the +Z side of the bottom of the winding portion 142 will be referred to as the inner bottom surface of the winding portion 142.

[0026] In the embodiment, the battery cell 100 can be placed on a plate (not shown in FIGS. 1 to 3) with the bottom of the winding portion 142 facing downward. When the battery cell 100 is placed on the plate with the bottom of the winding portion 142 facing downward, a plurality of battery cells 100 can be stacked on top of each other in the Y direction. Therefore, a plurality of battery cells 100 stacked on top of each other in the Y direction can be electrically connected to each other in series, in parallel, or in a combination of series and parallel to form a battery module.

[0027] In an embodiment, the spacer 150 at least partially contains an adhesive. Specifically, the spacer 150 is a cured adhesive. The adhesive is cured, for example, by drying. The spacer 150 is adhered to both the outer bottom surface of the laminate 110G and the inner bottom surface of the winding portion 142. Therefore, the outer bottom surface of the laminate 110G and the inner bottom surface of the winding portion 142 are physically joined to each other via the spacer 150. Accordingly, the mutual movement of the laminate 110G and the winding portion 142 due to an external impact on the battery cell 100 can be suppressed. Further, in the example shown in FIG. 3, the spacer 150 continuously extends along the outer bottom surface of the laminate 110G. Therefore, the plurality of battery elements 110 included in the laminate 110G are physically joined to each other via the spacer 150. Accordingly, the mutual movement of the plurality of battery elements 110 due to an external impact on the battery cell 100 can be suppressed. Thus, the function of the battery cell 100 can be improved.

[0028] The -Z side surface of the spacer 150 according to the embodiment can be formed to be substantially flat. When the -Z side surface of the spacer 150 is substantially flat, the battery cell 100 can be stably placed on a plate (not shown in FIGS. 1 to 3) with the bottom of the winding portion 142 directed downward as compared with the case where the spacer 150 is not provided. Further, as compared with the case where the outer bottom surface of the laminate 110G and the inner bottom surface of the winding portion 142 are in direct contact with each other without the spacer 150, it is easier to uniformly disperse the load on the bottom of the winding portion 142 due to the self-weight of the laminate 110G, and damage to the bottom of the winding portion 142 due to the self-weight of the laminate 110G can be suppressed. Therefore, the function of the battery cell 100 can be improved by the spacer 150.

[0029] The spacer 150 according to the embodiment may have thermal conductivity. In one example, the spacer 150 may at least partially include a thermally conductive adhesive. When the spacer 150 has thermal conductivity, the laminate 110G and the winding portion 142 can be thermally coupled to each other via the spacer 150. When the laminate 110G and the winding portion 142 are thermally coupled to each other via the spacer 150, compared with the case where the spacer 150 is not provided, the heat generated from each battery element 110 can be more easily released toward the bottom of the winding portion 142 through the spacer 150. For example, when the battery cell 100 is placed on a plate via a thermal conductive material such as a thermal glue with the bottom of the winding portion 142 facing downward, the heat generated from each battery element 110 can be more easily released to the plate through the spacer 150, the bottom of the winding portion 142, and the thermal conductive material. Therefore, the function of the battery cell 100 can be improved by the spacer 150.

[0030] The spacer 150 according to the embodiment may function as a reinforcing member that improves the strength of each battery element 110 included in the laminate 110G. When the spacer 150 functions as a reinforcing member, the strength of each battery element 110 can be improved compared with the case where the spacer 150 is not provided. Therefore, the function of the battery cell 100 can be improved by the spacer 150.

[0031] The spacer 150 does not have to be an adhesive. For example, the spacer 150 may be a rigid plate such as a resin plate. Even if the spacer 150 is a rigid plate, the battery cell 100 can be stably placed on a plate (not shown in FIGS. 1 to 3) with the bottom of the winding portion 142 facing downward, and damage to the bottom of the winding portion 142 due to the self-weight of the laminate 110G can be suppressed, compared with the case where the spacer 150 is not provided.

[0032] The position where the spacer 150 is disposed is not limited to the examples shown in FIGS. 1 to 3. The spacer 150 may be provided not only between the outer bottom surface of the laminate 110G and the inner bottom surface of the winding portion 142, but also at other portions between the outer peripheral surface around the X direction of the laminate 110G and the inner peripheral surface around the X direction of the winding portion 142. For example, when viewed from the X direction, the spacer 150 may be located on at least one of both sides in the longitudinal direction of the laminate 110G. That is, the spacer 150 may be located on at least one of the -Z side and the +Z side of the laminate 110G.

[0033] Next, an example of a method for manufacturing the battery cell 100 will be described. In the following example, the spacer 150 will be described as an adhesive in a liquid or gel state in an uncured state.

[0034] First, a plurality of battery elements 110 are formed. Next, the plurality of battery elements 110 are stacked to form a laminate 110G. Next, the lead-out positive current collector 112a and the -X side terminal 120 are electrically connected to each other, and the -X side surface of the laminate 110G is covered with the -X side lid member 130. The order of the electrical connection of the lead-out positive current collector 112a and the -X side terminal 120 and the covering of the -X side surface of the laminate 110G with the -X side lid member 130 is not particularly limited. Also, the lead-out negative current collector 114a and the +X side terminal 120 are electrically connected to each other, and the +X side surface of the laminate 110G is covered with the +X side lid member 130. The order of the electrical connection of the lead-out negative current collector 114a and the +X side terminal 120 and the covering of the +X side surface of the laminate 110G with the +X side lid member 130 is not particularly limited.

[0035] Next, the uncured spacer 150 is applied to the outer bottom surface of the laminate 110G. Next, with the spacer 150 in an uncured state, the winding portion 142 is wound around the laminate 110G and the pair of lid members 130 in the X direction. Next, the spacer 150 is cured by drying to physically bond the outer bottom surface of the laminate 110G and the inner bottom surface of the winding portion 142 to each other via the spacer 150.

[0036] Next, the outer peripheral surface of the lid member 130 on the -X side around the X direction and the inner peripheral surface of the -X side end portion of the exterior film 140 around the X direction are joined to each other by heat fusion. Also, the outer peripheral surface of the lid member 130 on the +X side around the X direction and the inner peripheral surface of the +X side end portion of the exterior film 140 around the X direction are joined to each other by heat fusion. Next, an electrolytic solution is injected into the space surrounded by the winding portion 142 between the pair of lid members 130 through the gap between the first lead-out portion 144a and the second lead-out portion 144b. Next, the space surrounded by the winding portion 142 between the pair of lid members 130 is evacuated through the gap between the first lead-out portion 144a and the second lead-out portion 144b. Next, the surfaces of the first lead-out portion 144a and the second lead-out portion 144b that contact each other are joined to each other by heat fusion.

[0037] The battery cell 100 is manufactured by the method described above.

[0038] As described above, the embodiments of the present invention have been described with reference to the drawings, but these are examples of the present invention, and various configurations other than the above can also be adopted.

[0039] For example, in the embodiment, the terminal 120 electrically connected to the positive electrode 112 and the terminal 120 electrically connected to the negative electrode 114 are located on both sides of the battery element 110 in the X direction. However, both the terminal 120 electrically connected to the positive electrode 112 and the terminal 120 electrically connected to the negative electrode 114 may be located on the same side of the +X side or -X side of the battery element 110.

Description of Reference Numerals

[0040] 100 Battery cell, 110 Battery element, 110G Stack, 112 Positive electrode, 112 Aligned positive electrodes, 112a Lead-out positive electrode current collector, 114 Negative electrode, 114a Lead-out negative electrode current collector, 116 Separator, 116a Zigzag portion, 116b Surrounding portion, 120 Terminal, 130 Lid member, 140 Exterior film, 142 Winding portion, 144 Lead-out portion, 144a First lead-out portion, 144b Second lead-out portion, 150 Spacer

Claims

1. A battery element; An exterior film wrapped around the battery element; a spacer located at least partially between the battery element and the exterior film; A battery cell comprising:

2. a terminal electrically connected to the battery element; the battery element has a shape having a longitudinal direction and a lateral direction perpendicular to a direction from a side where the battery element is located to a side where the terminal is located, The battery cell according to claim 1 , wherein at least a portion of the spacer is located on at least one of both sides of the battery element in the longitudinal direction.

3. The battery cell according to claim 1 , wherein the battery element and the exterior film are physically joined to each other via the spacer.

4. The battery cell according to claim 1 , wherein the battery element and the exterior film are thermally coupled to each other via the spacer.

5. The battery cell according to claim 1 or 2, wherein a plurality of the battery elements are physically joined to each other via the spacer.

6. The battery cell of claim 1 or 2, wherein the spacer comprises, at least in part, an adhesive.

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