battery pack

Abstract

To provide a technique that makes it possible to ensure more adequate insulation of a housing of a secondary battery.SOLUTION: A secondary battery 1 includes a box-shaped housing 10, an electrode body 30 accommodated in the housing 10, and an insulating film 40 covering a range from a lower end to an upper end of the housing 10. The insulating film 40 has a configuration in which, in a width direction of at least one side face (long side face) of a pair of side faces (long side faces) having a relatively large width of four side faces of the housing 10, an upper end in a center part is extended above upper ends of both end parts.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure provides: set electric In the pond Regarding. [Background technology]

[0002] For example, a secondary battery (electricity storage element) is known that has a box-shaped housing having a substantially rectangular parallelepiped shape and is provided with an insulating film covering the side surfaces thereof (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-58260 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, as the secondary battery is charged, the electrode assembly housed inside the housing may expand, causing the widthwise center of the box-shaped housing's side with the largest dimension to swell relatively significantly. In this case, as the thickness of the housing for the secondary battery increases, the insulating film may also displace to follow the change in thickness of the housing for the secondary battery, causing the upper end of the insulating film to slide below the upper end of the side of the housing. As a result, the insulation properties of the housing for the secondary battery may not be adequately ensured.

[0005] In view of the above-mentioned problems, an object of the present invention is to provide a technique that can more appropriately ensure the insulation of the housing of a secondary battery. [Means for solving the problem]

[0007] To achieve the above objectives , of this disclosure one In an embodiment, A plurality of secondary batteries, each of which has a box-shaped housing, an electrode body housed inside the housing, and an insulating film covering a range from the lower end to the upper end of a side surface of the housing, wherein the upper end of the central portion of the insulating film extends higher than the upper ends of both end portions in the width direction of at least one of a pair of side surfaces which has a relatively larger width among the four side surfaces of the housing, A plurality of electrodes arranged in a direction perpendicular to the pair of side surfaces No. 2 Next battery and a member disposed between two adjacent secondary batteries so as to be in contact with each of the insulating films, The member is disposed so that its upper end is located higher than the upper end of the side surface of the housing opposite to the member at the center in the width direction of the side surface. A battery pack is provided.

[0008] In another embodiment of the present disclosure, A plurality of secondary batteries, each of which has a box-shaped housing, an electrode body housed inside the housing, and an insulating film covering a range from the lower end to the upper end of a side surface of the housing, wherein the upper end of the central portion of the insulating film extends higher than the upper ends of both end portions in the width direction of at least one of a pair of side surfaces which has a relatively larger width among the four side surfaces of the housing, A plurality of electrodes arranged in a direction perpendicular to the pair of side surfaces No. 2 Next battery and a member disposed between two adjacent secondary batteries so as to be in contact with each of the insulating films, the member abuts against the insulating film at the center in the width direction of the side surface of the housing facing the member, only in a partial range including an upper end portion of the entire side surface in the up-down direction; A battery pack is provided. [Effects of the Invention]

[0009] According to the above-described embodiment, the insulation properties of the casing of the secondary battery can be more appropriately ensured. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view showing an example of a secondary battery. [Figure 2] FIG. 1 is a side view illustrating an example of a secondary battery. [Figure 3] FIG. 1 is a cross-sectional view showing an example of a secondary battery. [Figure 4] FIG. 2 is a diagram showing an example of an electrode body. [Figure 5] FIG. 1 is a perspective view showing a secondary battery according to a comparative example in a reference state. [Figure 6] FIG. 10 is a perspective view showing a secondary battery according to a comparative example in a swollen state of its housing. [Figure 7] FIG. 10 is a top view showing another example of a secondary battery. [Figure 8] FIG. 2 is a side view showing an example of a battery pack. [Figure 9] FIG. 2 is a top view showing an example of a battery pack. [Figure 10] FIG. 2 is a cross-sectional view showing an example of the structure of a spacer. [Figure 11] FIG. 10 is a top view showing another example of the structure of the spacer. [Figure 12] FIG. 10 is a cross-sectional view showing another example of the structure of the spacer. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment will be described with reference to the drawings.

[0012] [Example of a secondary battery] An example of a secondary battery 1 according to this embodiment will be described with reference to FIGS.

[0013] Fig. 1 is a perspective view showing an example of a secondary battery 1. Fig. 2 is a side view showing an example of a secondary battery 1. Fig. 3 is a cross-sectional view showing an example of a secondary battery 1. Specifically, Fig. 3 is a cross-sectional view taken along line AA in Fig. 2, which corresponds to the center of the secondary battery 1 in the X-axis direction. Fig. 4 is a perspective view showing an example of an electrode body 30.

[0014] 1 to 4 each show the reference state of the secondary battery 1 in which swelling of the casing 10 due to expansion or deterioration of the electrodes during charging has not occurred. Also, in Fig. 3, the insulating film 40 covering the bottom surface of the casing 10 (container portion 10A) is not shown.

[0015] The secondary battery 1 is a so-called prismatic secondary battery, and is, for example, a non-aqueous electrolyte secondary battery such as a lithium ion battery.

[0016] As shown in FIGS. 1 to 4, the secondary battery 1 includes a housing 10, an external terminal 20, an electrode body 30, and an insulating film 40.

[0017] The housing 10 contains the electrode assembly 30, an electrolytic solution, etc. The housing 10 is made of, for example, aluminum or stainless steel.

[0018] The housing 10 has a box-like shape. A box-like shape refers to a rectangular parallelepiped shape or a shape similar to a rectangular parallelepiped. Examples of shapes similar to a rectangular parallelepiped include, for example, a three-dimensional shape in which at least some of the corners of the rectangular parallelepiped are chamfered or rounded into a curved surface. Examples of shapes similar to a rectangular parallelepiped include, for example, a three-dimensional shape in which at least some of the surfaces of the rectangular parallelepiped are formed with irregularities for reinforcement or the like. Hereinafter, the X-axis and Y-axis are defined along the longitudinal and lateral directions, respectively, of the box-like shape when viewed from above, and the Z-axis direction is defined upward, and explanations will be provided using these coordinate axes. Furthermore, of the four side surfaces of the housing 10 (container portion 10A), the two side surfaces with relatively large widths (side surfaces parallel to the X-axis and Z-axis and perpendicular to the Y-axis) may be collectively or individually referred to as the "long side surfaces."

[0019] In this example, the ratio of the width (X-axis) dimension of the long side surface to the vertical dimension (Z-axis direction) (hereinafter referred to as the "aspect ratio") is set to be relatively large. The aspect ratio is set appropriately within the range of, for example, 2.0 to 10.0. In this example (FIG. 1), the aspect ratio is 3.0. This makes it possible to achieve an increased capacity while maintaining the height (vertical dimension) of the secondary battery 1.

[0020] The housing 10 includes a container portion 10A and a lid portion 10B.

[0021] The container 10A includes a substantially rectangular bottom plate and four side plates extending upward (in the positive direction of the Z axis) from the four sides of the rectangular bottom plate, which are integrally formed. The top end (the end in the positive direction of the Z axis) of the container 10A is open. This allows the electrode assembly 30 and the electrolytic solution to be contained inside the container 10A.

[0022] The lid 10B closes the opening at the top end of the container 10A.

[0023] The external terminals 20 are used to connect the secondary battery 1 to an external electric circuit. Specifically, two external terminals 20 corresponding to the positive and negative electrodes are provided, and the two external terminals 20 are attached to the upper surface of the lid portion 10B.

[0024] The electrode body 30 discharges electricity to the outside or is charged with electricity from the outside by chemical reaction with the electrolytic solution inside the container portion 10A.

[0025] As shown in FIG. 4, the electrode body 30 includes a main body 31 and a current collector 32.

[0026] The main body 31 is formed by winding a positive electrode plate, a negative electrode plate, and two separators interposed between the positive electrode plate and the negative electrode plate in a flat shape. When the electrode body 30 is housed in the housing 10 (container portion 10A), the winding axis of the main body 31 is arranged along the X-axis direction.

[0027] The current collectors 32 are used to extract the electrode stored in the electrode assembly 30 to the outside. Specifically, two current collectors 32 corresponding to both the positive and negative electrodes are provided at both ends of the main body 31 in the direction along the winding axis (X-axis). The two current collectors 32 are connected to two external terminals 20 of the container part 10A from the back side of the lid part 10B. The current collectors 32 are made of, for example, aluminum or copper.

[0028] The insulating film 40 ensures insulation between the secondary battery 1 (housing 10) and surrounding objects. The insulating film 40 is made of a resin such as polypropylene. The insulating film 40 is provided so as to cover each of the four side surfaces and the bottom surface of the housing 10 (container portion 10A), and is attached to the side surfaces of the housing 10 by, for example, thermal welding. The insulating films 40 covering each of the four side surfaces and the bottom surface of the housing 10 (container portion 10A) may be separate from one another, or some or all of them may be connected together as an integrated unit.

[0029] The insulating film 40 may be provided only on one of the four side surfaces of the housing 10 that needs to be insulated from surrounding objects. For example, as described below, when a battery pack 100 is configured by arranging a plurality of secondary batteries 1 along the Y-axis direction, the insulating film 40 may be provided only on one of the four side surfaces of the housing 10 of the secondary batteries 1 that is perpendicular to the Y-axis direction (i.e., the long side surface). Also, for example, in the case of a secondary battery 1 that is arranged at the end in the Y-axis direction, the insulating film 40 may be provided only on one of the two long sides on which the secondary batteries 1 adjacent in the Y-axis direction are arranged.

[0030] 1 to 3, at both ends of the long side surface of the housing 10 in the width direction (X-axis direction), the upper end positions of the insulating film 40 are substantially aligned with the upper end positions of the long side surface of the housing 10. In contrast, at the center of the long side surface of the housing 10 in the width direction, the insulating film 40 has an extension 40A that extends upward beyond the upper end position of the long side surface of the housing 10.

[0031] The extension amount of the extension portion 40A is set to be maximum at the center in the width direction of the long side surface of the housing 10, and to become smaller as it goes away from the center in the width direction.

[0032] The extension amount of the extension portion 40A may not change depending on the position in the width direction of the long side surface of the housing 10, and may be set to a constant value.

[0033] [Action of extension] Next, the function of the extension 40A of the insulating film 40 will be described with reference to FIGS.

[0034] Fig. 5 is a perspective view of a secondary battery 1c according to a comparative example. Specifically, Fig. 5 is a perspective view of the secondary battery 1c in a reference state in which swelling of the casing 10 due to electrode expansion, deterioration, etc. during charging has not occurred. Fig. 6 is a perspective view of the secondary battery 1c according to the comparative example in a state in which the casing 10 has swollen.

[0035] A secondary battery 1c according to a comparative example will be described below, with the same components as those of the secondary battery 1 according to this embodiment being denoted by the same reference numerals.

[0036] The secondary battery 1c according to the comparative example includes a housing 10, an external terminal 20, an electrode body 30, and an insulating film 40c.

[0037] Unlike the insulating film 40, the insulating film 40c has its upper end positioned substantially coincident with the upper end position of the long side surface of the housing 10 over the entire width of the long side surface of the housing 10.

[0038] Here, the electrodes included in the electrode assembly 30 expand during charging. Therefore, the volume of the electrode assembly 30 may expand in the Y-axis direction, causing the long side surfaces of the housing 10 to swell outward. In this case, the amount of expansion of the long side surfaces of the housing 10 (the amount of outward displacement of the housing 10) increases from both ends toward the center in the width direction (X-axis direction) of the long side surfaces, and is greatest at the center in the width direction. As a result, as shown in FIG. 6 , in the secondary battery 1c according to the comparative example, the upper end of the insulating film 40c may slide down at the center in the width direction (X-axis direction) of the long side surfaces, causing the upper end of the long side surfaces of the housing 10 to be exposed outside the coverage area of the insulating film 40c (see the outline arrow in the figure). In particular, when the aspect ratio (the width dimension of the long side surfaces) is relatively large, as in the secondary battery 1c according to the comparative example, the distance from both ends in the width direction of the long side surfaces to the center is relatively large, and therefore the force required to deform the center in the width direction of the long side surfaces outward from the housing 10 is relatively small. As a result, the amount of outward displacement of the housing 10 at the center of the width direction of the long side surface becomes even larger, making the insulating film 40c more likely to slide down and more likely to expose the upper end of the long side surface of the housing 10. Therefore, in the secondary battery 1c according to the comparative example, the insulating film 40c may not be able to adequately ensure the insulation of the housing 10.

[0039] In contrast, the insulating film 40 of the secondary battery 1 according to the above example (FIGS. 1 to 3) has the extension 40A as described above.

[0040] This increases the likelihood that the upper end of the long side surface of the housing 10 will be covered by the extension 40A, even if the insulating film 40 slides down in the widthwise center of the long side surface of the housing 10 as the housing 10 expands. Therefore, even if the housing 10 expands, the long side surface of the secondary battery 10 is less likely to be exposed outside the coverage area of the insulating film 40, and the insulating film 40 can more appropriately ensure the insulation of the housing 10.

[0041] If it is necessary to ensure insulation only on one of the two long sides of the housing 10, the extension 40A of the insulating film 40 may be omitted from the widthwise center of the other long side. That is, the extension 40A of the insulating film 40 may be provided only on the widthwise center of one of the two long sides of the housing 10 for which insulation is required. For example, as described below, if multiple secondary batteries 1 are arranged in the Y-axis direction, the extension 40A of the insulating film 40 may be omitted from the widthwise center (X-axis direction) of the outer long side in the Y-axis direction of the two long sides of the secondary batteries 1 located at both ends in the Y-axis direction. The same applies to other examples (FIG. 7) described below.

[0042] [Other examples of secondary batteries] Next, another example of the secondary battery 1 according to this embodiment will be described with reference to Fig. 7. The following description will focus on differences from the above example (Figs. 1 to 4), and descriptions of the same or corresponding content as the above example may be omitted.

[0043] FIG. 7 is a top view showing another example of the secondary battery 1 according to this embodiment.

[0044] In this example, the extension 40A of the insulating film 40 is folded so as to cover a portion of the top surface (lid portion 10B) of the housing 10. As a result, even if the long side surface of the housing 10 bulges outward, the extension 40A folded so as to cover the top surface of the housing 10 acts to prevent the insulating film 40 from sliding down at the center portion in the width direction of the long side surface of the housing 10. Therefore, the secondary battery 1 can more appropriately ensure the insulation properties of the housing 10.

[0045] Further, the extension 40A may be adhered to the top surface (lid 10B) of the housing 10 by welding or the like. This further prevents the insulating film 40 from sliding down at the center of the width direction of the long side surface of the housing 10, and more appropriately ensures the insulation properties of the housing 10.

[0046] [Battery configuration] Next, the configuration of the battery pack 100 will be described with reference to FIGS.

[0047] Fig. 8 is a side view showing an example of the battery pack 100. Fig. 9 is a top view showing an example of the battery pack 100.

[0048] As shown in FIGS. 8 and 9, the battery pack 100 includes a plurality of (six in this example) secondary batteries 1 and a spacer 110.

[0049] The plurality of secondary batteries 1 are arranged side by side in a direction perpendicular to the long side surfaces of the batteries (Y-axis direction).

[0050] A spacer 110 (an example of a component) is disposed between two adjacent secondary batteries 1 among the multiple secondary batteries 1 aligned in the Y-axis direction so as to contact the insulating films 40 of both secondary batteries 1. Therefore, the number of spacers 110 provided is the number of secondary batteries 1 aligned in the Y-axis direction minus one. In this example, five spacers 110 are provided for six secondary batteries 1.

[0051] The spacer 110 maintains the distance between two adjacent secondary batteries 1. The spacer 110 is made of an insulating material such as resin. This allows the two adjacent secondary batteries 1 to more reliably maintain insulation from each other through the spacer 110.

[0052] [Example of spacer structure] Next, an example of the structure of the spacer 110 will be described with reference to FIG.

[0053] Fig. 10 is a cross-sectional view showing an example of the structure of the spacer 110. Specifically, Fig. 10 is a cross-sectional view taken along line BB in Fig. 9, which corresponds to the center of the secondary battery 1 in the X-axis direction.

[0054] 10 depicts only two adjacent secondary batteries 1 and the spacer 110 therebetween, and does not depict other secondary batteries 1 or other spacers 110. For convenience, FIG. 10 depicts the secondary battery 1 according to the above-described example (FIGS. 1 to 4), but this may be replaced with the secondary battery 1 according to the above-described other example (FIG. 7).

[0055] As shown in FIG. 10 , the spacer 110 is located between two adjacent secondary batteries 1 and abuts against the two insulating films 40 in a range from the lower end to the upper end of the long sides of both housings 10, supporting both secondary batteries 1 (housings 10) from the sides. The upper end of the spacer 110 is located above the upper ends of the long sides of both housings 10. The portions of the spacer 110 below the upper ends of the long sides of the housings 10 are forced to undergo slight elastic deformation in the compression direction by being sandwiched between the housings 10, while the portions of the spacer 110 extending above the upper ends of the long sides of the secondary batteries 1 are not elastically deformed. Therefore, a relatively large pressure can be applied from the spacer 110 toward the corners at the upper ends of the long sides of the housings 10. Therefore, even if the long sides of the housing 10 swell, the insulating film 40 at the center of the width direction of the long sides of the housing 10 is prevented from sliding down, thereby more appropriately ensuring the insulation of the secondary batteries 1.

[0056] The upper end of the spacer 110 may be set higher than the upper end of the long side of the casing 10 only in the center of the entire range in the width direction (X-axis direction) of the long side of the adjacent secondary battery 1 (casing 10). Also, the upper end of the spacer 110 may be set higher than the upper end of the long side of the casing 10 not only in the center of the entire range in the width direction of the long side of the adjacent secondary battery 1 (casing 10), but also in a range including at least one of the end ends. Also, the structure of the spacer 110 of this example may be applied to a battery pack 100 in which the secondary battery 1 is replaced with the secondary battery 1c according to the comparative example described above.

[0057] [Other examples of spacer structures] Next, another example of the structure of the spacer 110 will be described with reference to FIGS.

[0058] Fig. 11 is a top view showing another example of the structure of the spacer 110. Fig. 12 is a cross-sectional view showing another example of the structure of the spacer 110. Specifically, Fig. 12 is a cross-sectional view taken along line CC in Fig. 11, which corresponds to the center of the secondary battery 1 in the X-axis direction.

[0059] 11 and 12, only two adjacent secondary batteries 1 and the spacer 110 therebetween are depicted, and other secondary batteries 1 and other spacers 110 are not depicted. Also, for convenience, Fig. 12 depicts the secondary battery 1 according to the above-described example (Figs. 1 to 4), but this may be replaced with the secondary battery 1 according to the above-described other example (Fig. 7).

[0060] As shown in FIG. 12, the spacer 110 is located between two adjacent secondary batteries 1 and abuts against the insulating film 40 covering the long side of one of the secondary batteries 1 (housing 10) (on the left side in the figure) in the range from the top to the bottom of the long side of that battery, thereby supporting that battery 1 from the side.

[0061] The spacer 110 also has a protrusion 110A at its upper end that protrudes laterally toward the long side of the other (left side in the figure) secondary battery 1 (housing 10). The protrusion 110A allows the spacer 110 to abut against the insulating film 40 covering the long side of the other secondary battery 1 (housing 10) only at the upper end of the area extending from the top to the bottom of the long side of the other secondary battery 1 (housing 10), thereby supporting the secondary battery 1 from the side. This allows for a relatively large surface pressure acting on the upper end of the widthwise center of the long side of the housing 10 across the insulating film 40 from the spacer 110. Therefore, even if the long side of the housing 10 of the other secondary battery 1 swells, the insulating film 40 at the widthwise center of the long side of the housing 10 is prevented from slipping down, thereby more appropriately ensuring the insulation of the secondary battery 1.

[0062] 11, the protrusion 110A is provided only in the center of the range between both ends in the width direction (X-axis direction) of the long side of the other secondary battery 1 (housing 10). This further increases the surface pressure acting on the upper end of the center in the width direction of the long side of the housing 10, sandwiching the insulating film 40 from the spacer 110. Therefore, even if the long side of the housing 10 of the other secondary battery 1 swells, the insulating film 40 in the center in the width direction of the long side of the housing 10 is further prevented from slipping down, and the insulation properties of the secondary battery 1 can be more appropriately ensured.

[0063] The protrusion 110A may be provided on both of the two secondary batteries 1 whose spacers 110 are adjacent to each other. The protrusion 110A may be provided not only in the center but also in a range including at least one of the two end portions in the width direction of the long side surface of the secondary battery 1 (housing 10). The protrusion 110A may be provided so as to abut against the insulating film 40 over a wider range in the vertical direction, as long as it abuts against the insulating film 40 only in a partial range including the upper end from the upper end to the lower end of the long side surface of the secondary battery 1 (housing 10). The structure of the spacer 110 of this example may be applied to a battery pack 100 in which the secondary battery 1 is replaced with the secondary battery 1c according to the comparative example described above.

[0064] [Effect] Next, the operation of the secondary battery 1 and the battery pack 100 according to this embodiment will be described.

[0065] In this embodiment, the secondary battery 1 includes a box-shaped housing 10, an electrode assembly 30 housed inside the housing 10, and an insulating film 40 covering the side surfaces of the housing 10 from the lower end to the upper end. The insulating film 40 has an upper end at the center that extends higher than the upper ends of both ends in the width direction of at least one of a pair of side surfaces (long sides) that are relatively wider among the four side surfaces of the housing 10.

[0066] This allows the secondary battery 1 to prevent the insulating film 40 from sliding down at the center of the width direction of the long side surface even when the housing 10 swells. Therefore, the secondary battery 1 can more appropriately ensure the insulation properties of the housing 10.

[0067] In addition, in this embodiment, the insulating film 40 may be folded so that the upper end of the central portion extends upward from the upper end of the long side in the width direction of at least one of the long sides, and that portion (extension portion 40A) covers part of the upper surface (lid portion 10B) of the housing 10.

[0068] This allows the secondary battery 1 to further prevent the insulating film 40 from sliding down at the center of the width direction of the long side surface when the casing 10 expands, thereby enabling the secondary battery 1 to more appropriately ensure the insulation properties of the casing 10.

[0069] In this embodiment, the battery pack 100 may include a plurality of secondary batteries 1 arranged side by side in a direction (Y-axis direction) perpendicular to the pair of long sides, and a spacer 110 arranged between two adjacent secondary batteries 1 so as to contact each insulating film 40. The spacer 110 may be arranged so that its upper end is higher than the upper end of the opposing long side of the housing 10 at the center in the width direction of the long side.

[0070] This allows the spacer 110 to apply a relatively large pressure toward the upper corner of the long side at the center of the width of the long side of the housing 10. Therefore, the battery pack 100 can further prevent the insulating film 40 from sliding down at the center of the width of the long side when the housing 10 expands. Therefore, the battery pack 100 can more appropriately ensure the insulation of the secondary battery 1 (housing 10).

[0071] In addition, in this embodiment, the spacer 110 may abut against the insulating film 40 in only a portion of the widthwise center of the long side of the housing 10 facing it, including the upper end of the entire long side in the vertical direction.

[0072] This allows the spacer 110 to apply a relatively large pressure toward the upper end of the long side surface at the center of the width of the long side surface of the housing 10. Therefore, the battery pack 100 can further prevent the insulating film 40 from sliding down at the center of the width of the long side surface when the housing 10 expands. Therefore, the battery pack 100 can more appropriately ensure the insulation of the secondary battery 1 (housing 10).

[0073] Although the embodiments have been described in detail above, the present disclosure is not limited to such specific embodiments, and various modifications and improvements are possible within the scope of the gist described in the claims. [Explanation of symbols]

[0074] 1 Secondary battery 10. Cabinet 10A container part 10B Lid 20 External terminal 30 Electrode body 31 Main Unit 32 Current collector 40 Insulating film 40A extension 100 battery packs 110 Spacer (component) 110A convex part

Claims

1. A plurality of secondary batteries each having a box-shaped housing, an electrode body housed inside the housing, and an insulating film covering the range from the lower end to the upper end of the side of the housing, wherein the upper end of the central part of the insulating film extends higher than the upper ends of both ends in the width direction of at least one of a pair of sides that are relatively wider among the four sides of the housing, and wherein the plurality of secondary batteries are arranged in a direction perpendicular to the pair of sides; a member disposed between two adjacent secondary batteries so as to be in contact with each of the insulating films, The member is disposed so that its upper end is located higher than the upper end of the side surface of the housing opposite to the member at the center in the width direction of the side surface. Battery pack.

2. A plurality of secondary batteries each having a box-shaped housing, an electrode body housed inside the housing, and an insulating film covering the range from the lower end to the upper end of the side of the housing, wherein the upper end of the central part of the insulating film extends higher than the upper ends of both ends in the width direction of at least one of a pair of sides that are relatively wider among the four sides of the housing, and wherein the plurality of secondary batteries are arranged in a direction perpendicular to the pair of sides; a member disposed between two adjacent secondary batteries so as to be in contact with each of the insulating films, the member abuts against the insulating film at the center in the width direction of the side surface of the housing facing the member, only in a partial range including an upper end portion of the entire side surface in the up-down direction; Battery pack.

3. The insulating film has an upper end of a central portion extending upward beyond the upper end of the at least one side surface in the width direction of the at least one side surface, and the portion is bent so as to cover a part of the upper surface of the housing. The battery pack according to claim 1 or 2.

Images