Battery cells and battery modules

Abstract

Improves the functionality of battery cells. A battery cell (10) includes a battery element (100) and an exterior material (400) that seals the battery element (100). The exterior material (400) forms a space that houses a functional material (500).

Description

[Technical Field]

[0001] The present invention relates to a battery cell and a battery module. [Background technology]

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

[0003] Patent Document 1 describes a battery cell. The battery cell includes an electricity storage element, a storage section that stores the electricity storage element, and an expansion section that communicates with the storage section.

[0004] Patent Document 2 describes a battery module. The battery module includes a plurality of battery cells arranged at predetermined intervals, and spacers that are positioned between adjacent battery cells and contain movably granular material. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2021-170513 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-072055 Summary of the Invention [Problem to be solved by the invention]

[0006] Battery cells are sometimes required to have improved functions, such as resistance to pressure, ability to accommodate thermal expansion or contraction, thermal insulation between battery cells, electrical insulation between battery cells, and suppression of battery cell deterioration.

[0007] One object of the present invention is to improve the performance of a battery cell. Other objects of the present invention will become apparent from the description herein. [Means for solving the problem]

[0008] One aspect of the present invention is as follows. 1. A battery element; an exterior material that seals the battery element; Equipped with The battery cell, wherein the exterior material forms a space for accommodating a functional material. 2. The battery cell according to claim 1, wherein the functional material includes at least one of an elastic material and a heat dissipation material. 3. The battery cell according to 1. or 2., wherein the portion of the exterior material that forms the space is pulled out from the portion of the exterior material that houses the battery element. 4. The battery cell according to any one of 1. to 3., wherein the space is at least partially divided into a plurality of spaces. 5. A battery pack comprising a plurality of battery cells according to any one of 1. to 4. a portion of the exterior material that forms the space is located between adjacent battery cells. [Effects of the Invention]

[0009] According to the above aspects of the present invention, the functionality of the battery cell can be improved. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view of a battery module according to an embodiment. [Figure 2] FIG. 2 is a perspective view of a battery cell according to the embodiment. [Figure 3] FIG. 2 is a side view of a battery cell according to an embodiment with the exterior material removed. [Figure 4] 3 is a cross-sectional view taken along the line AA in FIG. 2. [Figure 5] FIG. 10 is a cross-sectional view of a battery cell according to Modification 1. [Figure 6] FIG. 10 is a perspective view of a battery cell according to Modification 2. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments and modifications of the present invention will be described with reference to the drawings. In all the drawings, like components are designated by like reference numerals, and descriptions thereof will be omitted as appropriate.

[0012] Fig. 1 is a perspective view of a battery module 1 according to an embodiment. Fig. 2 is a perspective view of a battery cell 10 according to an embodiment. Fig. 3 is a side view of the battery cell 10 according to an embodiment with the exterior material 400 removed. Fig. 4 is a cross-sectional view taken along line AA in Fig. 2.

[0013] For ease of explanation, each figure is labeled with an X, Y, and Z direction. The X direction indicates the front-to-rear direction of the battery cell 10. The Y direction is perpendicular to the X direction. The Y direction indicates the left-to-right direction of the battery cell 10. The Z direction is perpendicular to both the X and Y directions. The Z direction indicates the up-to-down direction of the battery cell 10. The directions indicated by the arrows indicating the X direction, the Y direction, and the Z direction are the forward, right, and upward directions, respectively. However, the relationships between the X direction, Y direction, Z direction, front-to-back direction, left-to-right direction, and up-to-down directions of the battery cell 10 are not limited to this example. In FIG. 3, the white circle with a black dot indicating the Y direction indicates that the direction from the back of the page to the front is the direction indicated by the arrow indicating the Y direction. In FIG. 4, the white circle with a black dot indicating the X direction indicates that the direction from the back of the page to the front is the direction indicated by the arrow indicating the X direction.

[0014] Hereinafter, as necessary, the side indicated by the arrow indicating the X direction and the opposite side to the side indicated by the arrow indicating the X direction will be referred to as the +X side and the −X side, respectively; the side indicated by the arrow indicating the Y direction and the opposite side to the side indicated by the arrow indicating the Y direction will be referred to as the +Y side and the −Y side, respectively; and the side indicated by the arrow indicating the Z direction and the opposite side to the side indicated by the arrow indicating the Z direction will be referred to as the +Z side and the −Z side, respectively.

[0015] As shown in FIG. 1, a battery module 1 according to the embodiment includes a plurality of battery cells 10. As shown in FIG. 1, the plurality of battery cells 10 are stacked in the Y direction. Three battery cells 10 are schematically shown in FIG. 1. However, the number of battery cells 10 included in the battery module 1 is not limited to three, and may be two, or four or more. As shown in FIGS. 1 to 4, each battery cell 10 according to the embodiment includes a battery element 100, a first lid member 210, a second lid member 220, a first terminal 310, a second terminal 320, and an exterior material 400.

[0016] The battery element 100 has a pair of faces substantially perpendicular to the X direction, a pair of faces substantially perpendicular to the Y direction, and a pair of faces substantially perpendicular to the Z direction, and has a substantially rectangular parallelepiped shape with the dimension in the Z direction smaller than the dimension in the X direction and larger than the dimension in the Y direction. The shape of the battery element 100 is not limited to this example.

[0017] The battery element 100 includes at least one positive electrode (not shown), at least one negative electrode (not shown), and at least one separator (not shown). In one example, multiple positive electrodes and multiple negative electrodes are alternately stacked in the Y direction. At least a portion of the separator is located between adjacent positive electrodes and negative electrodes in the Y direction. Specifically, in one example, multiple sheet-like separators are each located between adjacent positive electrodes and negative electrodes in the Y direction. However, a single sheet-like separator may be alternately folded back at the +Z side end of the positive electrode and the -Z side end of the negative electrode, or alternately folded back at the -Z side end of the positive electrode and the +Z side end of the negative electrode. Alternatively, the positive electrode, negative electrode, and separator may be wound so that the separator is disposed between the positive electrode and the negative electrode. In one example, the positive electrode, negative electrode, and separator are wound with both sides of one of the positive electrode and negative electrode covered by the separator. In another example, a laminate including a plurality of unit laminates each including a positive electrode, a separator, and a negative electrode in this order may be wound, but the winding structure of the positive electrode, the negative electrode, and the separator is not limited to these examples.

[0018] In the embodiment, the battery cell 10 is a battery cell containing an electrolyte solution. However, the battery cell 10 may be an all-solid-state battery. In an all-solid-state battery, a solid electrolyte layer is provided in a portion corresponding to a separator. An all-solid-state battery does not contain an electrolyte solution. Hereinafter, unless otherwise specified, the battery cell 10 will be described as a battery cell containing an electrolyte solution.

[0019] As shown in Fig. 3, the first lid member 210 covers the end face on the +X side of the battery element 100. The first lid member 210 is made of, for example, at least one of resin and metal. As shown in Figs. 1 and 2, when viewed from the X direction, the first lid member 210 has a substantially rectangular shape having a pair of short sides substantially parallel to the Y direction and a pair of long sides substantially parallel to the Z direction.

[0020] 3, second lid member 220 covers the end face on the -X side of battery element 100. Second lid member 220 is made of, for example, at least one of resin and metal. When viewed from the X direction, second lid member 220 has a substantially rectangular shape with a pair of short sides substantially parallel to the Y direction and a pair of long sides substantially parallel to the Z direction.

[0021] As shown in FIG. 3 , the first terminal 310 is disposed on the +X side of the +X side end face of the battery element 100. The first terminal 310 protrudes from the first lid member 210 toward the +X side. The first terminal 310 is electrically connected to one of the positive electrode and the negative electrode included in the battery element 100 via the first current collector 110 drawn out from the +X side end face of the battery element 100. When the first terminal 310 and the positive electrode are electrically connected to each other, the first terminal 310 functions as a positive electrode terminal. When the first terminal 310 and the negative electrode are electrically connected to each other, the first terminal 310 functions as a negative electrode terminal.

[0022] As shown in FIG. 3 , the second terminal 320 is disposed on the −X side of the −X side end face of the battery element 100. The second terminal 320 protrudes from the second lid member 220 toward the −X side. The second terminal 320 is electrically connected to the other of the positive and negative electrodes included in the battery element 100 via the second current collector 120 drawn out from the −X side end face of the battery element 100. Therefore, the polarity of the first terminal 310 and the polarity of the second terminal 320 are opposite to each other. When the second terminal 320 and the positive electrode are electrically connected to each other, the second terminal 320 functions as a positive electrode terminal. When the second terminal 320 and the negative electrode are electrically connected to each other, the second terminal 320 functions as a negative electrode terminal.

[0023] 1, the battery cells 10 adjacent to each other in the Y direction are connected in series or in parallel via the first terminals 310 or the second terminals 320. For example, the first terminals 310 or the second terminals 320 of the battery cells 10 adjacent to each other in the Y direction are electrically connected to each other via a bus bar (not shown).

[0024] The exterior material 400 is made of, for example, a laminate film including a metal layer and resin layers provided on both sides of the metal layer. As shown in Figures 1, 2 and 4, the exterior material 400 has a wound portion 410 and a drawn-out portion 420.

[0025] As shown in FIG. 4 , the wound portion 410 is wound around the battery element 100, the first lid member 210, and the second lid member 220 one turn in the X direction. The wound portion 410 forms an internal space that accommodates the battery element 100 and an electrolyte solution (not shown). Hereinafter, unless otherwise specified, the internal space of the wound portion 410 refers to the internal space of the wound portion 410 that accommodates the battery element 100 and an electrolyte solution (not shown). The inner circumferential surface of the +X side end of the wound portion 410 and the outer circumferential surface of the first lid member 210 are joined to each other by, for example, heat fusion. Thus, the +X side end of the wound portion 410 and the first lid member 210 form a first sealing portion 452. The inner circumferential surface of the -X side end of the wound portion 410 and the outer circumferential surface of the second lid member 220 are joined to each other by, for example, heat fusion. Therefore, the −X side end of the wound portion 410 and the second lid member 220 form a second sealing portion 454.

[0026] 4, the drawn-out portion 420 is drawn out from a portion of the wound portion 410 covering a corner between the +Z side surface and the -Y side surface of the battery element 100, so as to cover a portion of the wound portion 410 covering the +Z side surface of the battery element 100 and a portion of the wound portion 410 covering the +Y side surface of the battery element 100. As shown in FIG. 4, the drawn-out portion 420 includes a first drawn-out film 420a drawn out from the portion of the wound portion 410 covering the +Z side surface of the battery element 100, and a second drawn-out film 420b drawn out from the portion of the wound portion 410 covering the -Y side surface of the battery element 100. Hereinafter, unless otherwise specified, the connection drawer portion 422 refers to the portion of the drawer portion 420 located on the +Z side relative to the +Z side surface of the battery element 100, and the storage drawer portion 424 refers to the portion of the drawer portion 420 located on the +Y side relative to the +Y side surface of the battery element 100. The way in which the drawer portion 420 is drawn out is not limited to the example shown in FIG.

[0027] The +Z side surface of the first extraction film 420a and the -Z side surface of the second extraction film 420b in the connection extraction portion 422 are joined to each other by, for example, heat fusion. Therefore, as shown in Figures 1, 2, and 4, the first extraction film 420a and the second extraction film 420b in the connection extraction portion 422 form a third sealing portion 456. The internal space of the wound portion 410 is sealed by the first sealing portion 452, the second sealing portion 454, and the third sealing portion 456. The exterior material 400 seals the battery element 100 and the electrolyte by sealing the internal space of the wound portion 410.

[0028] 1, 2, and 4, the +Y side surface of the first drawer film 420a and the -Y side surface of the second drawer film 420b in the storage drawer portion 424 are joined to each other, for example by heat sealing, along the +X side, -X side, and -Z side of the storage drawer portion 424. Thus, the +X side, -X side, and -Z side of the storage drawer portion 424 form a fourth sealed portion 458. As shown in FIGS. 1, 2, and 4, the storage drawer portion 424 is surrounded by the third sealed portion 456 and the fourth sealed portion 458, defining an internal space between the +Y side surface of the first drawer film 420a and the -Y side surface of the second drawer film 420b in the storage drawer portion 424. Unless otherwise specified, the internal space of the drawer section 420 refers to the internal space surrounded by the third sealing portion 456 and the fourth sealing portion 458 and existing between the +Y side surface of the first drawing film 420a and the -Y side surface of the second drawing film 420b in the storage drawer section 424. The internal space of the drawer section 420 is sealed by the third sealing portion 456 and the fourth sealing portion 458.

[0029] 4, a functional material 500 is housed in the internal space of the drawer portion 420. Therefore, the exterior material 400 not only seals the battery element 100 but also forms a space for housing the functional material 500.

[0030] The functional material 500 includes at least one of an elastic material and a heat dissipation material.

[0031] An example of the elastic material used in the functional material 500 is urethane foam. Another example of the elastic material used in the functional material 500 is elastic particles such as hollow particles made of resin. The elastic particles may be bound to each other by a binder such as resin, or may not be bound to each other. The elastic particles are made of, for example, an acrylic-styrene copolymer. The elastic particles have, for example, a hollow, approximately spherical shell shape. The material and structure of the elastic particles are not limited to the examples described above.

[0032] When the functional material 500 includes an elastic material, the storage drawer portion 424 can function as a compression pad. In the example shown in Fig. 1, the storage drawer portion 424 is located between adjacent battery cells 10 in the Y direction. By locating the storage drawer portion 424, which stores the functional material 500 and functions as a compression pad, between adjacent battery cells 10 in the Y direction, it is possible to improve the pressure resistance of each battery cell 10 and the ability to follow the thermal expansion or thermal contraction of each battery cell 10. Therefore, the functional material 500 can improve the functionality of the battery cells 10.

[0033] The functional material 500 may have electrical insulation properties. For example, the elastic material used in the functional material 500 may have electrical insulation properties. When the storage drawer section 424 that houses the electrically insulating functional material 500 is positioned between adjacent battery cells 10, electrical insulation between the battery cells 10 can be improved. Therefore, the functional material 500 can improve the functionality of the battery cells 10.

[0034] Examples of heat dissipation materials used in the functional material include metal plates and metal powders. When the functional material 500 includes a heat dissipation material, the storage drawer portion 424 can function as a heat dissipation member. Even if the heat dissipation member is a conductive material such as a metal plate or metal powder, the functional material 500 is contained in the internal space of the storage drawer portion 424, and therefore the functional material 500 can be electrically insulated from the surrounding area of ​​the storage drawer portion 424. In the example shown in FIG. 1 , the storage drawer portion 424 is located between battery cells 10 adjacent in the Y direction. By locating the storage drawer portion 424, which contains the functional material 500 and functions as a heat dissipation member, between the battery cells 10 adjacent in the Y direction, the heat dissipation of each battery cell 10 can be improved. Therefore, the functional material 500 can improve the function of the battery cells 10.

[0035] Next, an example of a method for manufacturing the battery cell 10 according to the embodiment will be described. In this example, the battery cell 10 is manufactured as follows.

[0036] First, the battery element 100 is formed. A first current collector 110 and a second current collector 120 are drawn out from the end face on the +X side and the end face on the −X side of the battery element 100, respectively.

[0037] Next, the first current collector 110 and the first terminal 310 are electrically connected to each other. For example, the first terminal 310 is provided in advance on the first lid member 210. Similarly, the second current collector 120 and the second terminal 320 are electrically connected to each other. For example, the second terminal 320 is provided in advance on the second lid member 220.

[0038] Next, the laminate film constituting the exterior material 400 is wrapped around the battery element 100, the first lid member 210, and the second lid member 220 in the X direction to form the wound portion 410 and the drawer portion 420. Specifically, the outer peripheral surface of the first lid member 210 and the inner peripheral surface of the +X side end of the wound portion 410 are joined together by heat fusion to form the first sealed portion 452. The outer peripheral surface of the second lid member 220 and the inner peripheral surface of the -X side end of the wound portion 410 are also joined together by heat fusion to form the second sealed portion 454. Next, with the functional material 500 positioned in the gap between the first drawer film 420a and the second drawer film 420b in the drawer portion 420, the third sealed portion 456 and the fourth sealed portion 458 are formed by heat fusion to accommodate the functional material 500 in the internal space of the storage drawer portion 424.

[0039] Next, an electrolyte solution is injected into the internal space of wound portion 410 through an injection hole provided in at least one of first lid member 210 and second lid member 220. Next, the internal space of wound portion 410 is vacuum-sealed through the injection hole. Next, the injection hole is closed with a lid.

[0040] In this manner, the battery cell 10 is manufactured.

[0041] 5 is a cross-sectional view of a battery cell 10A according to Modification 1. The battery cell 10A according to Modification 1 is similar to the battery cell 10 according to the embodiment, except for the following points.

[0042] The +Z side surface of the first drawn-out film 420a and the -Z side surface of the second drawn-out film 420b in the connecting drawn-out portion 422 of the exterior material 400A according to the modified example are joined to each other by, for example, heat sealing along the +Y side and the -Y side of the connecting drawn-out portion 422, but are not joined to each other along the +Y side and the -Y side of the connecting drawn-out portion 422. Therefore, the +Y side and the -Y side of the connecting drawn-out portion 422 of the exterior material 400A according to the modified example form a pair of third sealed portions 456A spaced apart from each other in the Y direction.

[0043] The connecting draw-out portion 422 of the exterior material 400A according to the first modification can function as a gas pocket for allowing gas generated from the battery element 100 to enter the internal space of the wound portion 410. Specifically, gas is generated from the battery element 100, increasing the pressure in the internal space of the wound portion 410, causing the bond between the +Z side surface of the first draw-out film 420a and the -Z side surface of the second draw-out film 420b to peel off at the third sealing portion 456A on the -Y side of the connecting draw-out portion 422. Therefore, the gas generated from the battery element 100 can enter the gap between the +Z side surface of the first draw-out film 420a and the -Z side surface of the second draw-out film 420b in the connecting draw-out portion 422.

[0044] Similar to the storage drawer portion 424 of the exterior material 400 according to the embodiment, the storage drawer portion 424 of the exterior material 400A according to the first modification forms a space for storing the functional material 500. Therefore, in the first modification, as in the embodiment, the functionality of the battery cell 10 can be improved by the functional material 500.

[0045] 6 is a perspective view of a battery cell 10B according to Modification 2. The battery cell 10B according to Modification 2 is similar to the battery cell 10 according to the embodiment, except for the following points.

[0046] The storage drawer portion 424 of the exterior packaging material 400B according to the second modification has a plurality of divided sealing portions 458B that at least partially divide the internal space of the storage drawer portion 424 into a plurality of spaces. Similar to the fourth sealing portion 458 shown in Fig. 4 according to the embodiment, the +Y side surface of the first drawing film 420a and the -Y side surface of the second drawing film 420b in each divided sealing portion 458B are joined to each other by, for example, heat sealing. 6, the multiple divided sealing portions 458B include a divided sealing portion 458B that at least partially divides the interior space of the storage drawer portion 424 into a space approximately in the center of the storage drawer portion 424 in the X direction and a space on the +X side of the storage drawer portion 424, and other divided sealing portions 458B that at least partially divide the interior space of the storage drawer portion 424 into a space approximately in the center of the storage drawer portion 424 in the X direction and a space on the -X side of the storage drawer portion 424. Each divided sealing portion 458B extends in the Z direction. The number and arrangement of the divided sealing portions 458B are not limited to the example shown in FIG. 6.

[0047] In the second modification, different types of functional materials 500 can be accommodated in the multiple spaces divided by the divided sealing portion 458B of the storage drawer portion 424. In one example, the space approximately in the center in the X direction of the storage drawer portion 424 accommodates the functional material 500 including a heat dissipation material, and the spaces on both sides in the X direction of the storage drawer portion 424 accommodate the functional material 500 including an elastic material. In this example, the approximately center in the X direction of the storage drawer portion 424, where the temperature of the battery cells 10 tends to be high, can function as a heat dissipation member, and the both sides in the X direction of the storage drawer portion 424 can function as compression pads at the both sides in the X direction of the battery cells 10.

[0048] In the second modification, the same type of functional material 500 may be stored in multiple spaces divided by the divided sealing portion 458B of the storage drawer portion 424. By dividing the internal space of the storage drawer portion 424 into multiple spaces, uneven distribution of the functional material 500 stored in the storage drawer portion 424 can be more easily suppressed.

[0049] Although the embodiments and modifications of the present invention have been described above with reference to the drawings, these are merely examples of the present invention, and various configurations other than those described above can also be adopted.

[0050] The type of functional material and the functions improved by the functional material of the battery cells are not limited to the examples described in the embodiments and modifications. The type of functional material is determined from the perspective of improving functions such as pressure resistance, compliance with thermal expansion or thermal contraction, thermal insulation between battery cells, electrical insulation between battery cells, and suppression of battery cell degradation. [Explanation of symbols]

[0051] 1 Battery module, 10, 10A, 10B Battery cell, 100 Battery element, 110 First current collector, 120 Second current collector, 210 First cover material, 220 Second cover material, 310 First terminal, 320 Second terminal, 400, 400A, 400B Exterior material, 410 Wrapping portion, 420 Pull-out portion, 420a First pull-out film, 420b Second pull-out film, 422 Connecting pull-out portion, 424 Storage pull-out portion, 452 First sealing portion, 454 Second sealing portion, 456, 456A Third sealing portion, 458 Fourth sealing portion, 458B Divided sealing portion, 500 Functional material

Claims

1. A battery element; an exterior material that seals the battery element; Equipped with The battery cell, wherein the exterior material forms a space for accommodating a functional material.

2. The battery cell according to claim 1 , wherein the functional material includes at least one of an elastic material and a heat dissipation material.

3. The battery cell according to claim 1 or 2, wherein a portion of the exterior material that forms the space is pulled out from a portion of the exterior material that houses the battery element.

4. The battery cell according to claim 1 or 2, wherein the space is at least partially divided into a plurality of spaces.

5. A battery pack according to claim 1 or 2 is provided, a portion of the exterior material that forms the space is located between adjacent battery cells.

Images