Battery cell

Abstract

To improve the functionality of a structure that faces an end surface of a battery element at least partially.SOLUTION: A battery cell 10 includes a battery element 100, and a front lid material 210 that faces, at a predetermined distance from, an end surface of the battery element 100 at least partially. The front lid material 210 includes a front projection part 214 on the side where the end surface of the battery element 100 is located. The front lid material 210 defines a front depression space 216 that is depressed toward the front projection part 214 from a side of a front lid plate 212 opposite to the side where the end surface of the battery element 100 is located.SELECTED DRAWING: Figure 3

Description

[Technical field]

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

[0002] In recent years, various types of battery cells have been developed. A battery cell has a battery element having a positive electrode, a negative electrode, and a separator.

[0003] Patent Document 1 describes an example of a battery cell. This battery cell includes an exterior material that seals a battery element. The battery element is provided with a positive electrode lead and a negative electrode lead. A temperature sensor is disposed in the negative electrode lead.

[0004] Patent Document 2 describes arranging a temperature sensor on the side surface of a unit cell.

[0005] Patent Document 3 describes inserting a temperature sensor into a hole provided in a battery case and an upper lid that accommodate an electrode plate group. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2007-335352 A [Patent Document 2] JP 2013-171699 A [Patent Document 3] JP 2002-50411 A Summary of the Invention [Problem to be solved by the invention]

[0007] A battery cell may include a structure that at least partially faces an end face of a battery element at a predetermined distance. However, when the structure simply faces the end face of the battery element, it may be difficult to improve the functionality of the structure.

[0008] One object of the present invention is to improve the functionality of a structure at least partially facing an end face of a battery element. Other objects of the present invention will become apparent from the description of this specification. [Means for solving the problem]

[0009] One aspect of the present invention is as follows. 1. A battery element; a structure at least partially facing an end surface of the battery element at a predetermined distance; Equipped with the structure has a protrusion located on a side where the end surface of the battery element is located, The structure defines a recessed space recessed toward the protrusion from a side of the structure opposite to a side on which the end face of the battery element is located. 2. The battery cell described in 1., further comprising a temperature sensor, at least a portion of which is disposed within the recessed space. 3. The battery cell according to claim 1 or 2, wherein the protrusion exhausts gas generated from the battery element when abnormal heat generation occurs in the battery element. 4. The battery cell described in any one of 1. to 3., wherein the structure defines a plurality of the recessed spaces. 5. The battery cell according to any one of 1. to 4., wherein the structure has a lid material that covers the end face of the battery element. 6. The battery cell according to any one of 1. to 5., wherein the structure has a conductor electrically connected to the battery element. Effect of the Invention

[0010] According to the above-described aspect of the present invention, it is possible to improve the functionality of the structure that at least partially faces the end face of the battery element. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is a perspective view of a battery cell according to an embodiment. [Diagram 2]FIG. 2 is a perspective view of a battery cell according to an embodiment with an exterior film removed. [Diagram 3] 2 is a cross-sectional view taken along line AA in FIG. 1. [Figure 4] FIG. 11 is a perspective view of a front cover member according to a first modified example of the embodiment. [Diagram 5] 5 is a cross-sectional view of a battery cell according to a first modified example of the embodiment, taken at a position corresponding to the cross section BB in FIG. 4. [Figure 6] FIG. 11 is a perspective view of a front cover member according to a second modified example of the embodiment. [Figure 7] 7 is a cross-sectional view of a battery cell according to a second modified example of the embodiment, taken at a position corresponding to cross section CC in FIG. 6. [Figure 8] FIG. 13 is a perspective view of a front cover member according to a third modified example of the embodiment. [Figure 9] FIG. 11 is a cross-sectional view of a battery cell according to a fourth modified example of the embodiment. [Figure 10] FIG. 13 is a cross-sectional view of a front conductor according to a fifth modified example of the embodiment. [Figure 11] FIG. 11 is a cross-sectional view of a battery cell according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, embodiments and modifications of the present invention will be described with reference to the drawings. In all the drawings, similar components are given similar reference numerals and descriptions thereof will be omitted as appropriate.

[0013] Fig. 1 is a perspective view of a battery cell 10 according to an embodiment. Fig. 2 is a perspective view of the battery cell 10 according to an embodiment with an exterior film 400 removed. Fig. 3 is a cross-sectional view taken along line AA in Fig. 1. For the sake of explanation, the temperature sensor 500 shown in Fig. 3 has been removed from Figs. 1 and 2. For the sake of explanation, the exterior film 400 shown in Fig. 1 has been removed from Fig. 3.

[0014] For the sake of explanation, each figure is labeled with an X direction, a Y direction, and a Z direction. The X direction indicates the front-rear direction of the battery cell 10. The Y direction is perpendicular to the X direction. The Y direction indicates the left-right direction of the battery cell 10. The Z direction is perpendicular to both the X direction and the Y direction. The Z direction indicates the up-down direction of the battery cell 10. The direction indicated by the arrow indicating the X direction, the direction indicated by the arrow indicating the Y direction, and the direction indicated by the arrow indicating the Z direction are the forward direction, the left direction, and the upward direction, respectively. However, the relationship between the X direction, the Y direction, the Z direction, the front-rear direction, the left-right direction, and the up-down direction of the battery cell 10 is not limited to this example. In FIG. 3, a white circle with a black dot indicating the Y direction indicates that the direction from the back of the paper to the front is the direction indicated by the arrow indicating that direction.

[0015] As shown in FIGS. 1 to 3, the battery cell 10 includes two battery elements 100, a front cover member 210, a rear cover member 220, a front conductor 310, a rear conductor 320, an exterior film 400, and a temperature sensor 500.

[0016] As shown in Figs. 2 and 3, two battery elements 100 are stacked in the Z direction. Each battery element 100 has a substantially rectangular parallelepiped shape. The dimension of each battery element 100 in the X direction is the dimension in the longitudinal direction of each battery element 100. The dimension of each battery element 100 in the Y direction is the dimension in the lateral direction of each battery element 100. The dimension of each battery element 100 in the Z direction is the dimension in the thickness direction of each battery element 100. However, the shape of the battery element 100 is not limited to this example. The number of battery elements 100 included in the battery cell 10 may be only one or three or more.

[0017] Each battery element 100 has at least one positive electrode (not shown), at least one negative electrode (not shown), and at least one separator (not shown). In one example, a plurality of positive electrodes and a plurality of negative electrodes are alternately stacked in the Z direction. At least a portion of the separator is located between the positive electrodes and the negative electrodes adjacent in the Z direction. Specifically, in one example, each of a plurality of sheet-like separators is located between the positive electrodes and the negative electrodes adjacent in the Z direction. However, one sheet-like separator may be alternately folded back at the left end of the positive electrode and the right end of the negative electrode, or alternately folded back at the right end of the positive electrode and the left end of the negative electrode. Alternatively, the positive electrode, the negative electrode, and the separator may be wound so that the separator is disposed between the positive electrode and the negative electrode. In one example, the positive electrode, the negative electrode, and the separator are wound in a state in which both sides of one of the positive electrode and the negative electrode are covered by the separator. In another example, a laminate including a plurality of unit laminates 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. However, the battery cell 10 may be an all-solid-state battery. In the all-solid-state battery, a solid electrolyte layer is provided in a portion corresponding to a separator. The all-solid-state battery does not contain an electrolyte.

[0019] Unless otherwise specified, hereinafter, each battery element 100 will be described as including a plurality of positive electrodes and a plurality of negative electrodes alternately stacked in the Z direction.

[0020] As shown in FIG. 3, a plurality of positive electrode collectors 110 are drawn out from the front end surface of each battery element 100. The plurality of positive electrode collectors 110 are integrated with the plurality of positive electrodes of each battery element 100 and are electrically connected to the plurality of positive electrodes of each battery element 100. The plurality of positive electrode collectors 110 are bundled together. In FIG. 3, the plurality of positive electrode collectors 110 bundled together are depicted as one solid. As shown in FIG. 3, the bundle of the plurality of positive electrode collectors 110 has a tapered bundle portion 112 and a drawn bundle portion 114. In the tapered bundle portion 112, the Z-direction distance between the positive electrode collectors 110 adjacent to each other in the Z direction decreases toward the front. The front end portion of the tapered bundle portion 112 is positioned shifted upward with respect to the center of the two positive electrode collectors 110 in the Z direction. The positive electrode current collectors 110 in the drawn bundle portion 114 are joined to each other by a joining method such as ultrasonic joining. When viewed from the Y direction, the positive electrode current collectors 110 in the drawn bundle portion 114 are drawn out from the front end of the tapered bundle portion 112 in a substantially L-shape. Specifically, the drawn bundle portion 114 includes a first drawn bundle portion 114a and a second drawn bundle portion 114b. The first drawn bundle portion 114a extends forward in the X direction from the front end of the tapered bundle portion 112. The second drawn bundle portion 114b is bent downward from the front end of the first drawn bundle portion 114a and extends in the Z direction. However, the drawing method of the positive electrode current collectors 110 is not limited to the example shown in FIG. 3.

[0021] A plurality of negative electrode current collectors (not shown) are drawn out from the rear end surface of each battery element 100 in the same manner as the plurality of positive electrode current collectors 110 drawn out from the front end surface of each battery element 100. The plurality of negative electrode current collectors are integrated with the plurality of negative electrodes of each battery element 100 and are electrically connected to the plurality of negative electrodes of each battery element 100.

[0022] 3, the front cover member 210 has a front cover plate 212 and a front protrusion 214. The front cover member 210 is a structure that at least partially faces the front end face of the battery element 100 at a predetermined distance in the X direction.

[0023] As shown in Fig. 3, the front cover plate 212 covers the front end surface of the battery element 100 with the rear surface of the front cover plate 212 and the front end surface of the battery element 100 separated from each other in the X direction. The front cover plate 212 is, for example, a resin plate. As shown in Fig. 2, when viewed from the front, the front cover plate 212 has a substantially rectangular shape having a pair of long sides substantially parallel to the Y direction, a pair of short sides substantially parallel to the Z direction, and four rounded corners. However, the shape of the front cover plate 212 is not limited to this example.

[0024] 3, the front convex portion 214 is located on the rear side of the front cover plate 212. The front convex portion 214 and the front cover plate 212 are integral with each other. For example, the front convex portion 214 and the front cover plate 212 are integrally formed by resin molding. The front convex portion 214 according to the embodiment has a substantially quadrangular prism shape. However, the shape of the front convex portion 214 is not limited to this.

[0025] The front cover member 210 defines a front recessed space 216. The front recessed space 216 is recessed from the front side of the front cover plate 212 toward the front protrusion 214. For example, the front recessed space 216 is a recess formed by resin molding of the front cover plate 212 and the front protrusion 214. The front recessed space 216 according to the embodiment has a substantially quadrangular prism shape. However, the shape of the front recessed space 216 is not limited to this.

[0026] As shown in FIG. 2, the front convex portion 214 and the front concave space 216 are positioned above the center of the front cover plate 212 in the Y and Z directions when viewed from the front. The dimension of the front cover plate 212 in the Y direction is larger than the dimension of the front cover plate 212 in the Z direction. Therefore, the strength of the front cover member 210 can be improved when the front convex portion 214 is provided on the upper or lower part of the front cover plate 212 in the Y and Z directions, compared to when the front convex portion 214 and the front concave space 216 are provided on the left or right part of the front cover plate 212 in the Y and Z directions. However, the position where the front convex portion 214 is provided is not limited to the example shown in FIG. 2 and FIG. 3. For example, the front convex portion 214 and the front concave space 216 may be provided on the left or right part of the front cover plate 212 in the Y and Z directions.

[0027] The matters described for the front cover member 210 according to the embodiment are also applicable to the rear cover member 220. As shown in FIG. 2, the rear cover member 220 according to the embodiment has a rear cover plate 222 corresponding to the front cover plate 212 and a rear convex portion 224 corresponding to the front convex portion 214, similar to the front cover member 210 according to the embodiment. The rear cover plate 222 covers the rear end surface of the battery element 100. The rear convex portion 224 is located on the front side of the front convex portion 214. The rear cover member 220 according to the embodiment defines a rear recessed space recessed from the rear side of the rear cover plate 222 toward the rear convex portion 224, similar to the front cover member 210 according to the embodiment.

[0028] As shown in FIG. 3, the front conductor 310 includes a front barrier conductor 312 and a forward protruding conductor 314 .

[0029] 3, the front barrier conductor 312 covers at least a part of the rear surface of the front cover plate 212. With the front barrier conductor 312 covering at least a part of the rear surface of the front cover plate 212, the front convex portion 214 of the front cover member 210 penetrates a conductor hole 313 provided in the center of the upper part of the front barrier conductor 312 in the Y direction. The front barrier conductor 312 is, for example, a metal. The front barrier conductor 312 is less permeable to moisture than the front cover plate 212. Therefore, when the front barrier conductor 312 is provided, it is possible to reduce moisture reaching each battery element 100 from the front side of the front cover member 210, compared to when the front barrier conductor 312 is not provided.

[0030] 3, the forward protruding conductor 314 is located at the center in the Y direction and the Z direction on the front surface of the front barrier conductor 312. The forward protruding conductor 314 and the front barrier conductor 312 are integral with each other. With the front barrier conductor 312 covering at least a part of the rear surface of the front cover plate 212, the forward protruding conductor 314 passes through a central hole 213 provided in the center in the Y direction and the Z direction of the front cover plate 212.

[0031] 3, the forward projecting conductor 314 has a solid structure. For example, the forward projecting conductor 310 is formed by joining a conductor plate serving as the forward barrier conductor 312 and a conductor block serving as the forward projecting conductor 314 to each other. Alternatively, the forward projecting conductor 310 may be formed by integrally extruding the forward barrier conductor 312 and the forward projecting conductor 314. When the forward projecting conductor 314 has a solid structure, heat generation in the forward conductor 310 can be suppressed compared to a case in which the forward projecting conductor 314 projects from the forward barrier conductor 312 by embossing and a space recessed from the forward barrier conductor 312 is present behind the forward projecting conductor 314A.

[0032] The rear surface of the front barrier conductor 312 and the front surface of the second lead bundle portion 114b are joined to each other by a joining method such as laser welding or ultrasonic bonding. Therefore, the forward protruding conductor 314 and the multiple positive electrodes of each battery element 100 are electrically connected to each other via the front barrier conductor 312 and the multiple positive electrode current collectors 110. Thus, the forward protruding conductor 314 serves as a positive electrode terminal of the battery cell 10. However, the electrical connection between the front conductor 310 and each battery element 100 is not limited to the above example. For example, the front conductor 310 and the multiple positive electrode current collectors 110 may be electrically connected to each other via another conductor disposed between the front conductor 310 and the multiple positive electrode current collectors 110.

[0033] 1 and 2, the front barrier conductor 312 is provided with one forward protruding conductor 314. However, the front barrier conductor 312 may be provided with a plurality of forward protruding conductors 314.

[0034] The matters described regarding the front conductor 310 according to the embodiment are similarly applicable to the rear conductor 320. As shown in Fig. 2, the rear conductor 320 according to the embodiment has a rear barrier conductor 322 corresponding to the front barrier conductor 312 and a rear protruding conductor (not shown) corresponding to the forward protruding conductor 314, similar to the front conductor 310 according to the embodiment.

[0035] As shown in FIG. 1, the exterior film 400 is wrapped around the battery element 100, the front cover material 210, and the rear cover material 220 in the X direction. The exterior film 400 has a generally cylindrical shape that opens both front and rear. The front cover material 210 is disposed inside the front opening of the exterior film 400. The rear cover material 220 is disposed inside the rear opening of the exterior film 400. Thus, the front cover material 210, the rear cover material 220, and the exterior film 400 form a storage space that stores the battery element 100, the multiple positive electrode collectors 110, and the multiple negative electrode collectors. The storage space stores the battery element 100, the multiple positive electrode collectors 110, and the multiple negative electrode collectors, as well as an electrolyte (not shown).

[0036] The outer periphery in the X direction of the front cover plate 212 and the inner periphery in the X direction of the front end of the exterior film 400 are joined to each other by, for example, heat fusion. Therefore, a sealed portion is formed between the outer periphery in the X direction of the front cover plate 212 and the inner periphery in the X direction of the front end of the exterior film 400.

[0037] The outer periphery in the X direction of the rear cover plate 222 and the inner periphery in the X direction of the rear end of the exterior film 400 are joined to each other by, for example, heat fusion. Therefore, a sealed portion is formed between the outer periphery in the X direction of the rear cover plate 222 and the inner periphery in the X direction of the rear end of the exterior film 400.

[0038] In one example, the exterior film 400 has a wound portion that is wound around the battery element 100, the front cover member 210, and the rear cover member 220 in the X direction, and two drawn-out portions that are drawn out from both ends of the wound portion in the X direction. The two drawn-out portions are joined to each other by, for example, heat fusion. Thus, a sealing portion is formed between the two drawn-out portions.

[0039] The temperature sensor 500 is a thermistor. As shown in Fig. 3, the temperature sensor 500 has a sealant 502 and a dumet wire 504. The sealant 502 is, for example, glass that seals a chip such as a thermistor chip. The dumet wire 504 is electrically connected to the chip sealed in the sealant 502. However, the structure of the temperature sensor 500 is not limited to the example shown in Fig. 3.

[0040] 3, the sealing body 502 is disposed at the rear end of the front recessed space 216. The Dumet wire 504 is drawn from the rear end of the sealing body 502 to the outside of the front recessed space 216 via the front opening of the front recessed space 216. Thus, the front recessed space 216 functions as an accommodation space for accommodating at least a part of the temperature sensor 500. Therefore, in the embodiment, the functionality of the front cover member 210 can be improved compared to a case where the front recessed space 216 is not provided.

[0041] 3, the temperature sensor 500 is positioned offset upward from the center of the front cover plate 212 in the Z direction. At least a portion of the first drawn bundle portion 114a is positioned offset upward from the center of the positive electrode current collectors 110 in the Z direction. Therefore, compared to a case in which the first drawn bundle portion 114a is positioned at the center of the positive electrode current collectors 110 in the Z direction, the sealing body 502 and the positive electrode current collectors 110 can be brought closer to each other, making it easier for the temperature sensor 500 to detect the temperature of the positive electrode current collectors 110 more accurately. However, the first drawn bundle portion 114a may be positioned at the center of the positive electrode current collectors 110 in the Z direction.

[0042] As shown in Fig. 3, the rear end surface of the front recessed space 216 is located rearward of the rear surface of the front cover plate 212. Therefore, compared to a case in which the front recessed space 216 is provided in a front cover plate 212 having the same thickness in the X direction as the front cover plate 212 shown in Fig. 3 without providing a front protrusion 214, the depth in the X direction of the front protrusion 214 can be made deeper, and the volume of the front recessed space 216 can be made larger. Furthermore, compared to a case in which the front recessed space 216 is provided in a front cover plate 212 having the same dimension in the X direction as the dimension in the X direction of the front protrusion 214 shown in Fig. 3 without providing a front protrusion 214, the dimension in the X direction of the front cover member 210 can be made smaller, and the dimension in the X direction of the battery cell 10 can be made smaller.

[0043] The front convex portion 214 can function as an open valve for discharging gas generated from the battery element 100 when the battery element 100 generates abnormal heat. When the battery element 100 generates abnormal heat, high-temperature gas may be generated from the battery element 100. The melting point of the front convex portion 214 is equal to or lower than the temperature around the front convex portion 214 when the battery element 100 generates abnormal heat. Therefore, when the battery element 100 generates abnormal heat, at least a portion of the front convex portion 214 can melt. By melting at least a portion of the front convex portion 214, the front convex portion 214 can discharge gas generated from the battery element 100 when the battery element 100 generates abnormal heat. Therefore, in the embodiment, the functionality of the front cover member 210 can be improved compared to when the front convex portion 214 is not provided.

[0044] In order to exhaust gas generated from the battery element 100 when the battery element 100 abnormally heats up, the thickness between the outer surface of the front convex portion 214 and the inner surface of the front concave space 216 in the front cover member 210 may be relatively thin, for example, may be equal to or smaller than the thickness in the X direction of the front cover plate 212. In order to preferentially exhaust gas from the portion between the rear end surface of the front convex portion 214 and the rear end surface of the front concave space 216 in the front cover member 210, the thickness of the portion between the rear end surface of the front convex portion 214 and the rear end surface of the front concave space 216 in the front cover member 210 may be less than the thickness of the portion between the outer surface around the X direction of the front convex portion 214 in the front cover member 210 and the inner surface around the X direction of the front concave space 216.

[0045] 3, at least a portion of the temperature sensor 500 is disposed inside the front recessed space 216. However, the temperature sensor 500 does not have to be disposed inside the front recessed space 216. Even when the temperature sensor 500 is not disposed inside the front recessed space 216, the front protrusion 214 can function as a release valve that opens at least a portion of the front recessed space 216 when abnormal heat generation occurs in the battery element 100. Therefore, the functionality of the front cover member 210 can be improved compared to when the front protrusion 214 is not provided.

[0046] The element disposed inside the front recessed space 216 is not limited to the temperature sensor 500 .

[0047] Next, an example of a method for manufacturing the battery cell 10 according to this embodiment will be described.

[0048] First, two battery elements 100 are stacked on each other. Each battery element 100 has at least one positive electrode, at least one negative electrode, and at least one separator. A plurality of positive electrode current collectors 110 and a plurality of negative electrode current collectors are drawn out from the two battery elements 100. Next, the tip portions of the plurality of positive electrode current collectors 110 that will become the drawn bundle portion 114 are joined to each other by a joining method such as ultrasonic joining to form a bundle, thereby forming the tapered bundle portion 112 and the drawn bundle portion 114. Before the drawn bundle portion 114 and the front conductor 310 are joined to each other, the tip portion that will become the second drawn bundle portion 114b of the drawn bundle portion 114 is not bent relative to the base end portion that will become the first drawn bundle portion 114a of the drawn bundle portion 114, and the drawn bundle portion 114 is drawn out toward the front of each battery element 100. Similarly, the tip portions of the plurality of negative electrode current collectors are also joined to each other to form a bundle.

[0049] Next, the front cover member 210 and the front conductor 310 are prepared. Next, the front cover member 210 and the front conductor 310 are attached to each other in a state in which the front convex portion 214 of the front cover member 210 penetrates the conductor hole 313 of the front barrier conductor 312 and the forward protruding conductor 314 of the front conductor 310 penetrates the central hole 213 of the front cover plate 212. Next, the tip portion of the lead bundle portion 114 that will become the second lead bundle portion 114b and the surface of the front barrier conductor 312 on the opposite side of the front cover plate 212 are joined to each other by a joining method such as laser welding or ultrasonic joining. Next, the tip portion of the lead bundle portion 114 that will become the second lead bundle portion 114b is bent toward the first lead bundle portion 114a that will become the base end portion of the lead bundle portion 114, and the front end surface of each battery element 100 is covered by the front cover plate 212. Similarly, the plurality of negative electrode current collectors and the rear conductors 320 are also joined to each other.

[0050] Next, the exterior film 400 is wrapped around the battery element 100, the front cover material 210, and the rear cover material 220 in the X direction by one turn. Next, the outer periphery of the front cover material 210 in the X direction and the inner periphery of the front end of the exterior film 400 in the X direction are joined together by heat fusion to form a sealed portion between the outer periphery of the front cover material 210 in the X direction and the inner periphery of the opening of the front end of the exterior film 400 in the X direction. Next, the outer periphery of the rear cover material 220 in the X direction and the inner periphery of the rear end of the exterior film 400 in the X direction are joined together by heat fusion to form a sealed portion between the outer periphery of the rear cover material 220 in the X direction and the inner periphery of the rear end of the exterior film 400 in the X direction. With these sealing parts formed, the front cover material 210, the rear cover material 220 and the exterior film 400 form a storage space that stores the battery element 100, the plurality of positive electrode current collectors 110 and the plurality of negative electrode current collectors. The exterior film 400 has two drawn-out portions drawn out from both ends around the X direction of a wrapped portion that is wrapped around the battery element 100, the front cover material 210 and the rear cover material 220 one turn around the X direction.

[0051] Next, an electrolyte solution is injected into the storage space through the gap between the two drawn-out portions of the exterior film 400. Next, the storage space is evacuated through the gap between the two drawn-out portions of the exterior film 400. Next, the two drawn-out portions of the exterior film 400 are joined by heat fusion to form a sealing portion, and the storage space is vacuum-sealed.

[0052] In this manner, the battery cell 10 according to the embodiment is manufactured.

[0053] Fig. 4 is a perspective view of a front cover member 210A1 according to a first modified example of the embodiment. Fig. 5 is a cross-sectional view of a battery cell 10A1 according to a first modified example of the embodiment at a position corresponding to cross section BB in Fig. 4. The battery cell 10A1 according to the first modified example of the embodiment is similar to the battery cell 10 according to the embodiment, except for the following points.

[0054] 4, the front cover member 210A1 has a front cover plate 212A and four front protrusions 214A. The front cover member 210A1 defines four front recessed spaces 216A. Each front recessed space 216A according to the modified example is recessed from the front side of the front cover member 210A1 toward the front recessed space 216A, similar to the front recessed space 216 according to the embodiment.

[0055] As shown in FIG. 4, two of the four front protrusions 214A and two of the four front recessed spaces 216A are located above the center of the front cover plate 212A in the Y direction and the Z direction. These two front protrusions 214A are lined up in the Y direction together with these two front recessed spaces 216A. The other two of the four front protrusions 214A and the other two of the four front recessed spaces 216A are located below the center of the front cover plate 212A in the Y direction and the Z direction. These other two front protrusions 214A are lined up in the Y direction together with these two other front recessed spaces 216A.

[0056] 5, a front conductor 310A according to the modified example has a front barrier conductor 312A and a forward protruding conductor 314A. The front barrier conductor 312A covers at least a part of the rear surface of the front cover plate 212A with the forward protruding conductor 314A penetrating the central hole 213A of the front cover plate 212A and the front protrusions 214A penetrating the conductor holes 313A of the front barrier conductor 312A.

[0057] Hereinafter, as necessary, in Figure 5, the front convex portion 214A and the front concave space 216A located above the center of the front cover plate 212A in the Z direction will be referred to as the upper front convex portion 214A and the upper front concave space 216A, respectively, and in Figure 5, the front convex portion 214A and the front concave space 216A located below the center of the front cover plate 212A in the Z direction will be referred to as the lower front convex portion 214A and the lower front concave space 216A, respectively.

[0058] As shown in FIG. 5, at least a part of the temperature sensor 500 is disposed inside the upper front concave space 216A. In FIG. 4, the temperature sensor 500 may be disposed in only one or both of the two front concave spaces 216A located above the center of the front cover member 210A1 in the Y direction and the Z direction. As shown in FIG. 5, at least a part of the first drawn bundle portion 114a is positioned shifted upward with respect to the center of the positive electrode current collectors 110 in the Z direction. Therefore, in FIG. 5, disposing the temperature sensor 500 inside the upper front concave space 216A rather than inside the lower front concave space 216A allows the sealing body 502 and the positive electrode current collectors 110 to be closer to each other, and makes it easier for the temperature sensor 500 to detect the temperature of the positive electrode current collectors 110 more accurately.

[0059] As shown in Fig. 5, the temperature sensor 500 is not disposed inside the lower front recessed space 216A. In Fig. 4, for example, the temperature sensor 500 is not disposed in either of the two front recessed spaces 216A located below the center of the front cover member 210A1 in the Y direction and the Z direction. Therefore, compared to the case where the temperature sensor 500 is disposed inside the lower front recessed space 216A, there is no member that obstructs the flow of gas inside the lower front recessed space 216A, and the lower front protrusion 214A can easily function as an open valve that exhausts gas generated from the battery element 100 when the battery element 100 generates abnormal heat.

[0060] 4 and 5, the front cover member 210A1 defines a plurality of front recessed spaces 216A. Therefore, it is possible to select whether or not to provide a temperature sensor 500 for each of the plurality of front recessed spaces 216A.

[0061] Fig. 6 is a perspective view of a front cover member 210A2 according to a second modified example of the embodiment. Fig. 7 is a cross-sectional view of a battery cell 10A2 according to a second modified example of the embodiment at a position corresponding to cross section CC in Fig. 6. The battery cell 10A2 according to the second modified example of the embodiment is similar to the battery cell 10 according to the embodiment, except for the following points.

[0062] As shown in Fig. 6, one front protrusion 214A may be provided on each of the upper and lower parts of the front cover plate 212A with respect to the center in the Y direction and the Z direction. As shown in Fig. 6, the front protrusion 214A provided on the upper side with respect to the center in the Y direction and the Z direction of the front cover plate 212A and the front protrusion 214A provided on the lower side with respect to the center in the Y direction and the Z direction of the front cover plate 212A may be positioned on opposite sides with respect to the center in the Y direction of the front cover plate 212A.

[0063] As shown in Fig. 7, the seal 502 may be disposed inside the front recessed space 216A located below the center in the Z direction of the front cover plate 212A. In the example shown in Fig. 7, the seal 502 and the tapered bundle portion 112 can be brought closer to each other than when the seal 502 is disposed inside the front recessed space 216A located above the center in the Z direction of the front cover plate 212A, and it is therefore easier to detect the temperatures of the positive electrode current collectors 110 in the tapered bundle portion 112 more accurately.

[0064] 8 is a perspective view of a front cover material 210A3 according to a third modified example of the embodiment. The front cover material 210A3 according to the third modified example of the embodiment is similar to the front cover material 210 according to the embodiment, except for the following points.

[0065] 8, no front protrusion 214A may be provided below the center in the Z direction of the front cover plate 212A, and two front protrusions 214A may be provided above the center in the Z direction of the front cover plate 212A. Alternatively, no front protrusion 214A may be provided above the center in the Z direction of the front cover plate 212A, and two front protrusions 214A may be provided below the center in the Z direction of the front cover plate 212A.

[0066] 9 is a cross-sectional view of a battery cell 10A4 according to a fourth modified example of the embodiment. The battery cell 10A4 according to the fourth modified example of the embodiment is similar to the battery cell 10 according to the embodiment, except for the following points.

[0067] The front cover member 210A4 has a front cover plate 212A and a front protrusion 214A. The front conductor 310A4 extends parallel to the X direction and penetrates the upper part of the front cover plate 212A. The front protrusion 214A and the front recessed space 216A are located in the center of the front cover plate 212A in the Z direction. Therefore, the sealing body 502 can be arranged on the front side of the center of the two battery elements 100 in the Z direction.

[0068] Fig. 10 is a cross-sectional view of a front conductor 310A5 according to a fifth modified example of the embodiment. Fig. 10 shows a cross section of the center part in the Y direction of the front conductor 310A5 according to the fifth modified example of the embodiment.

[0069] 10, the forward protruding conductor 314A5 may be protruding forward from the front barrier conductor 312A5 by embossing. A space recessed forward from the rear surface of the front barrier conductor 312A5 exists behind the forward protruding conductor 314A5. As in the embodiment, the front barrier conductor 312A5 is provided with a conductor hole 313A5 through which the front convex portion of the front cover member penetrates. When the forward protruding conductor 314A5 is formed by embossing, the weight of the front conductor 310A5 can be reduced compared to when the forward protruding conductor 314A5 is solid.

[0070] 11 is a cross-sectional view of a battery cell 10B according to a modified example. The battery cell 10B according to the modified example is similar to the battery cell 10 according to the embodiment, except for the following points.

[0071] The front conductor 310B has a front barrier conductor 312B, a front protruding conductor 314B, and a front convex portion 316B. The front conductor 310B is a structure at least partially opposed to the front end face of the battery element 100 at a predetermined distance in the X direction.

[0072] The front barrier conductor 312B covers at least a portion of the rear surface of the front cover member 210B. The rear surface of the front barrier conductor 312B and the front surface of the second lead bundle portion 114b are joined to each other by a joining method such as laser welding or ultrasonic joining.

[0073] The forward protruding conductor 314B is located at the center in the Y and Z directions on the front surface of the front barrier conductor 312B. The forward protruding conductor 314B and the front barrier conductor 312B are integrated. With the front barrier conductor 312B covering at least a part of the rear surface of the front cover member 210B, the forward protruding conductor 314B passes through a central hole 213B provided in the center in the Y and Z directions of the front cover member 210B.

[0074] The front convex portion 316B is located on the rear surface side of the front barrier conductor 312B. When viewed from the X direction, the front convex portion 316B is located in the center in the Y and Z directions of the rear surface of the front barrier conductor 312B. The front convex portion 316B and the front barrier conductor 312B are integrated. The position of the front convex portion 316B with respect to the front barrier conductor 312B is not limited to the example shown in FIG. 11. The front barrier conductor 312B may be provided with a plurality of front convex portions 316B.

[0075] The front conductor 310B defines a front recessed space 318B. The front recessed space 318B is recessed from the front side of the forward protruding conductor 314B toward the front convex portion 316B. The front recessed space 318B is opened toward the front of the forward protruding conductor 314B via a through hole that penetrates the forward protruding conductor 314B in the X direction.

[0076] The sealing body 502 is disposed at the rear end of the front recessed space 318B. The Dumet wire 504 is drawn from the rear end of the sealing body 502 to the outside of the front recessed space 318B via the front opening of the front recessed space 318B. Thus, the front recessed space 318B functions as an accommodation space for accommodating at least a part of the temperature sensor 500. Therefore, in the modified example, the functionality of the front conductor 310B can be improved compared to a case where the front recessed space 318B is not provided.

[0077] The front convex portion 316B according to the modified example may function as a release valve for discharging gas generated from the battery element 100 when the battery element 100 generates abnormal heat, similarly to the front convex portion 214 according to the embodiment. When the front convex portion 316B can function as a release valve, the functionality of the front conductor 310B can be improved compared to a case in which the front convex portion 316B is not provided.

[0078] Although the embodiment and modified examples 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.

[0079] The structure in which the front protrusion and the front recessed space are provided is not limited to the front cover material or the front conductor. The front protrusion and the front recessed space can be provided in a structure that is at least partially opposed to the front end face of the battery element 100 at a predetermined distance.

[0080] For example, in the embodiment, a positive terminal such as a forward-projecting conductor 314 and a negative terminal such as a rear-projecting conductor are arranged on opposite sides of the battery element 100 in the X direction. However, both the positive terminal and the negative terminal may be arranged only on one of the front side and the rear side of the battery element 100 in the X direction. When both the positive terminal and the negative terminal are arranged only on one of the front side and the rear side of the battery element 100 in the X direction, for example, the front end and the rear end of the battery element 100 are covered by two lid materials. Alternatively, only the side of the battery element 100 from which the positive terminal and the negative terminal are pulled out may be covered by a lid material. When only the side of the battery element 100 from which the positive terminal and the negative terminal are pulled out is covered by a lid material, the exterior film 400 may be sealed on the opposite side of the lid material of the battery element 100 and folded along the battery element 100. [Explanation of symbols]

[0081] 10,10A1,10A2,10A4,10B Battery cell, 100 Battery element, 110 Positive electrode current collector, 112 Tapered bundle part, 114 Pull-out bundle part, 114a 1st pull-out bundle part, 114b 2nd draw-out bundle part, 210,210A1,210A2,210A3,210A4,210B Front lid material, 212,212A Front lid plate, 213,213A,213B Center hole, 214,214A Front convex part, 216,216A Front concave space, 220 Rear lid material, 222 Rear lid plate, 224 Rear convex part, 310,310A,310A4,310A5,310B Front conductor, 312, 312A, 312A5, 312B Front barrier conductor, 313, 313A, 313A5 Conductor hole, 314, 314A, 314A5, 314B Forward protruding conductor, 316B Front convex portion, 318B Front concave space, 320 Rear conductor, 322 Rear barrier conductor, 400 Outer film, 500 Temperature sensor, 502 Encapsulation body, 504 Dumet wire

Claims

1. A battery element; a structure at least partially facing an end surface of the battery element at a predetermined distance; Equipped with the structure has a protrusion located on a side where the end surface of the battery element is located, The structure defines a recessed space recessed toward the protrusion from a side of the structure opposite to a side on which the end face of the battery element is located.

2. The battery cell of claim 1 , further comprising a temperature sensor disposed at least in part within the recessed space.

3. The battery cell according to claim 1 , wherein the protrusion exhausts gas generated from the battery element when abnormal heat generation occurs in the battery element.

4. The battery cell of claim 1 , wherein the structure defines a plurality of the recessed spaces.

5. The battery cell according to claim 1 , wherein the structure has a lid material that covers the end face of the battery element.

6. The battery cell according to any one of claims 1 to 4, wherein the structure has a conductor electrically connected to the battery element.

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