Partition member

Abstract

The present invention addresses the problem of providing a partition member (1) capable of following deformation of a cell (92) during normal use, and capable of suppressing thermal propagation between a plurality of the cells (92) during an abnormality. The partition member (1) comprises a heat insulation sheet (2). The heat insulation sheet (2) has a sheet body (20) and an ear part (21) that protrudes outward in the edgewise direction from the sheet body (20). During normal use, a gap (22) overlapping the ear part (21) when viewed from the lamination direction is secured to the outside of the sheet body (20) in the edgewise direction.

Description

Partition material

[0001] The present disclosure relates to a partition member disposed in a stack of cells of a battery module.

[0002] In a stack of battery modules, a partition member is interposed between a pair of adjacent cells in the stacking direction. Patent Document 1 discloses a partition member including a thermal insulator and an auxiliary member. The auxiliary member is disposed on the outer surface of the thermal insulator. The thermal insulator and the auxiliary member are deformable independently of each other. When the cells expand during charging, the thermal insulator contracts accordingly. At this time, the auxiliary member restricts excessive contraction of the thermal insulator. This ensures the restoration of the thermal insulator when the cells contract during discharging. Therefore, it is possible to prevent gaps from forming between the partition member and the cells not only when the cells expand but also when the cells contract. Therefore, efficient heat conduction is achieved between a pair of adjacent cells via the partition member.

[0003] Thus, Patent Document 1 discloses a technology for ensuring good thermal conduction between a pair of adjacent cells by constantly and completely contacting the partition member with the cells during normal use (when the cells are charged or discharged) without being affected by the expansion or contraction of the cells. To ensure good thermal conduction, the space between the pair of adjacent cells is filled with a partition member without any gaps.

[0004] Re-table 2019 / 189850 publication

[0005] However, if the partition member is tightly packed in the space between a pair of adjacent cells, the partition member is less likely to deform in response to the deformation (expansion and contraction) of the cells during normal use. Furthermore, if any cell generates heat or expands abnormally, the heat is likely to be transferred to another cell adjacent to the cell across the partition member. In other words, in the event of an abnormality, a thermal chain reaction is likely to occur between adjacent cells.

[0006] Therefore, an object of the present disclosure is to provide a partition member that can follow the deformation of cells during normal use and can suppress thermal chain reaction between multiple cells in the event of an abnormality.

[0007] (1) In order to solve the above problem, the partition member of the present disclosure is a partition member having an insulating sheet interposed between any pair of adjacent cells in the stacking direction in a stack of multiple cells, wherein the direction intersecting the stacking direction is the layer direction, and the time when the cells deform due to normal charging and discharging is the time of normal use, and the insulating sheet has a sheet body and ear portions protruding outward in the layer direction from the sheet body, and during the time of normal use, a gap is secured on the outside of the sheet body in the layer direction that overlaps with the ear portions when viewed from the stacking direction.

[0008] During normal use, the insulating sheet has, along the stacking direction, a ``section where part of the sheet body and the ear part are arranged'' (hereinafter referred to as ``ear part setting section'' as appropriate) and a ``section where other parts of the sheet body and gaps are arranged'' (hereinafter referred to as ``gap setting section'' as appropriate).

[0009] The gap-defined section is more likely to deform in the stacking direction than the lug-defined section. Therefore, the partition member is more flexible (has a smaller spring constant in the stacking direction) due to the gaps. Therefore, the partition member can deform in response to the deformation (expansion and contraction) of the cells.

[0010] During normal use, a gap is continuously maintained in the gap-defined section. That is, a gap is maintained not only during cell contraction (e.g., during discharge) but also during cell expansion (e.g., during charge). In contrast, even during abnormal conditions (when cells expand or contract abnormally compared to normal use), the ears in the ear-defined section continue to be interposed between a pair of adjacent cells in the stacking direction. Therefore, contact between a pair of adjacent cells can be suppressed even during abnormal conditions. Therefore, heat transfer between a pair of adjacent cells can be suppressed even during abnormal conditions.

[0011] (1-1) In the configuration of (1) above, the heat insulating sheet is a compression-molded product of a granular porous material, which is a porous body formed from granular substances. Air has low thermal conductivity and high heat insulating properties. A compression-molded product of a granular porous material has many pores inside, and air is retained within the pores. Therefore, with this configuration, the heat insulating properties of the heat insulating sheet can be improved.

[0012] (1-2) In any of the above configurations, the cell has a range where the partition member is in close contact and a range where it is not in close contact during normal use, and when viewed from the stacking direction, the ear portion and the gap are arranged to overlap the range where it is not in close contact (hereinafter referred to as range A).

[0013] According to this configuration, when viewed from the stacking direction, the ears and gaps are arranged so as to overlap in range A. During normal use, a continuous gap is maintained between the ears and the cells, ensuring the necessary flexibility of the partition member.

[0014] On the other hand, in the event of an abnormality, even if any cell expands in the stacking direction, the ears prevent the cell from contacting other cells adjacent to it in the stacking direction. This prevents heat from being transferred from the abnormally heated cell to the surrounding cells. In other words, it prevents a thermal chain reaction from occurring between multiple cells.

[0015] (1-3) In any of the above configurations, the first gap is positioned adjacent to the cell on one side of the stacking direction, the second gap is positioned adjacent to the cell on the other side of the stacking direction, and the ear portion is positioned between the first gap and the second gap.

[0016] Here, the form in which the gap is arranged "close to" the cell includes a form in which no other member or part is interposed between the gap and the cell, and a form in which another member or part is interposed between the gap and the cell.

[0017] According to this configuration, during normal use, a pair of gaps (a first gap that mainly absorbs deformation of the cells on one side of the stacking direction, and a second gap that mainly absorbs deformation of the cells on the other side of the stacking direction) can be secured on both sides of the ear portion in the stacking direction.

[0018] (1-4) In any of the above configurations, the first ear portion is positioned adjacent to the cell on one side of the stacking direction, the second ear portion is positioned adjacent to the cell on the other side of the stacking direction, and the gap is positioned between the first ear portion and the second ear portion.

[0019] Here, the configuration in which the ear portion is positioned "close to" the cell includes a configuration in which no other members or parts are interposed between the ear portion and the cell, and a configuration in which other members or parts are interposed between the ear portion and the cell.

[0020] With this configuration, during normal use, a gap (a shared gap that absorbs deformation of the pair of cells on both sides in the stacking direction) can be secured midway between the pair of ear portions in the stacking direction.

[0021] (2) In any of the above configurations, the ear portion is arranged adjacent to the cell on one side in the stacking direction, and the gap is arranged adjacent to the cell on the other side in the stacking direction.

[0022] Here, the configuration in which the ears are disposed "close to" the cells includes a configuration in which no other member or part is interposed between the ears and the cells, and a configuration in which another member or part is interposed between the ears and the cells. The same applies to a configuration in which the gaps are disposed "close to" the cells.

[0023] This configuration ensures that a gap (a shared gap that absorbs deformation of a pair of cells on both sides of the stacking direction) is secured on the other side of the ear portion during normal use. Furthermore, the shape of the heat insulating sheet is simple, which reduces the manufacturing cost of the heat insulating sheet.

[0024] (3) In any of the above configurations, the ear portion has an endless annular shape when viewed from the stacking direction. With this configuration, contact between a pair of adjacent cells in the stacking direction can be suppressed over the entire circumference of the partition member.

[0025] (4) In any of the configurations (1) and (2) above, the ears have an end shape when viewed from the stacking direction. This configuration can prevent contact between a pair of adjacent cells in the stacking direction.

[0026] (5) In any of the above configurations, the heat insulating sheet is configured as a one-piece member. The heat insulating sheet is a one-piece member (single member). Therefore, compared to a heat insulating sheet made up of multiple independent members (for example, a sheet body and edge portions), the number of parts of the heat insulating sheet and, by extension, the partition member can be reduced. Also, manufacturing costs can be reduced.

[0027] (6) In any of the above (1) to (4), the heat insulating sheet is configured as an integrated body of a plurality of independent members. With this configuration, the characteristics of the heat insulating sheet can be adjusted by combining the materials and properties of the plurality of members, compared to when the heat insulating sheet is a single unit.

[0028] The partition member of the present disclosure can accommodate deformation of the cells during normal use, and can also suppress thermal chain reaction between multiple cells during abnormal use.

[0029] FIG. 1 is an exploded perspective view of a battery module including a partition member according to a first embodiment. FIG. 2 is a top view of the same battery module. FIG. 3 is a cross-sectional view in the front-rear direction within frame III in FIG. 2. FIG. 4 is a cross-sectional view along the IV-IV direction in FIG. 3. FIG. 5 is an enlarged view of frame V in FIG. 3. FIG. 6 is an enlarged view of frame V in FIG. 3 during an abnormality. FIG. 7 is a partial cross-sectional view in the front-rear direction of a partition member according to a second embodiment. FIG. 8 is a partial cross-sectional view in the front-rear direction of a partition member according to a third embodiment. FIG. 9 is a partial cross-sectional view in the front-rear direction of a partition member according to a fourth embodiment. FIG. 10 is a front view of a partition member according to a fifth embodiment.

[0030] Hereinafter, an embodiment of the partition member of the present disclosure will be described.

[0031] <First embodiment> Fig. 1 shows an exploded perspective view of a battery module equipped with a partition member of this embodiment. Fig. 2 shows a top view of the same battery module. Fig. 3 shows a cross-sectional view in the front-rear direction within frame III in Fig. 2 (cross-sectional view in the III-III direction in Fig. 4). Fig. 4 shows a cross-sectional view in the IV-IV direction in Fig. 3. Fig. 5 shows an enlarged view of frame V in Fig. 3. Fig. 6 shows an enlarged view of frame V in Fig. 3 during an abnormality. Note that the cells 92 and partition members 1 shown in Figs. 1 to 5 are the cells 92 and partition members 1 during normal times. The film 4 is omitted in Fig. 4.

[0032] In these figures, the front-to-rear direction corresponds to the "stacking direction" in the present disclosure. The rear side corresponds to the "one stacking direction" in the present disclosure. The front side corresponds to the "other stacking direction" in the present disclosure. The direction perpendicular to (intersecting with) the front-to-rear direction (the direction included in the plane extending in the up-down and left-right directions) corresponds to the "side-layer direction" in the present disclosure.

[0033] [Arrangement and Configuration of Partition Member] First, the arrangement and configuration of the partition member of this embodiment will be described. As shown in Figures 1 and 2, the partition member 1 of this embodiment is incorporated into an on-vehicle battery module 9. The battery module 9 includes a housing 90 and a laminated body 91.

[0034] The housing 90 has a box-like shape with a bottom that opens upward. The housing 90 extends in the front-to-rear direction. The stack 91 includes a plurality of cells (secondary batteries) 92 and a plurality of partition members 1. The cells 92 and the partition members 1 are stacked alternately in the front-to-rear direction.

[0035] As shown in FIGS. 1 to 3 , the cell 92 has a flattened rectangular parallelepiped shape extending in the up-down and left-right directions. That is, the cell 92 is a prismatic cell. The cell 92 includes two terminals 920, a case 921, and an internal container 922 (schematically shown in the figures). The terminals 920 of adjacent cells 92 in the front-to-rear direction are electrically connected by a bus bar (not shown). As shown in FIGS. 3 to 5 , a region A, where the partition member 1 does not come into close contact, is defined on both front-to-rear sides of the case 921 of the cell 92. When viewed from the front-to-rear direction, the region A has a rectangular frame shape (endless annular shape).

[0036] Note that range A does not have to be endless annular. Range A may have ends. For example, range A may be a part of the endless annular range A shown in FIG. 4. Furthermore, the number of end-shaped ranges A may be one or more.

[0037] 1 and 2, the partition member 1 is interposed between any pair of cells 92 adjacent in the front-rear direction in the stack 91. As shown in Fig. 4, the partition member 1 has a flat plate shape extending in the up-down and left-right directions.

[0038] As shown in Figures 3 to 5, the partition member 1 includes a heat insulating sheet 2, a nonwoven fabric container 3, and a film 4. The heat insulating sheet 2 is a compression-molded product of silica aerogel. The heat insulating sheet 2 is a one-piece body. The heat insulating sheet 2 includes a sheet body 20, an edge portion 21, and a gap 22. The sheet body 20 has a rectangular plate shape. As shown in Figure 4, the edge portion 21 has the same shape as area A. As shown in Figure 5, the edge portion 21 is disposed adjacent to the rear cell 92, via a lid 31 and a wall portion of the film 4, which will be described later. As shown in Figure 4, the edge portion 21 protrudes outward in the up, down, left, and right directions from the rear of the side surface of the sheet body 20 (the outer surface of the sheet body 20 that extends in the front-to-rear direction; specifically, the upper, lower, left, and right surfaces).

[0039] As shown in Figures 3 to 5, the gap 22 is secured on the outer side in the up, down, left, and right directions of the sheet main body 20 at least during normal use (when the cells 92 deform due to charging and discharging during normal use) and during abnormal conditions (when the cells 92 expand abnormally compared to normal use). As shown in Figure 4, the gap 22 has the same shape as range A. As shown in Figure 5, the gap 22 is disposed adjacent to the front cell 92. The gap 22 is disposed in front of the ear 21, with the wall of the container main body 30 interposed between them. That is, as shown in Figure 4, the gap 22 and the ear 21 overlap when viewed from the front-to-back direction. Furthermore, when viewed from the front-to-back direction, the ear 21 and the gap 22 overlap with range A.

[0040] As shown in Figures 3 to 5, the nonwoven fabric container 3 covers the heat insulating sheet 2 from the outside. As shown in Figure 5, the nonwoven fabric container 3 is made of nonwoven fabric and includes a container body 30 and a lid 31. The container body 30 has a rectangular box shape (bag shape) that opens toward the rear. The heat insulating sheet 2 is housed inside the container body 30. The lid 31 seals the opening of the container body 30 from the rear. The film 4 covers the nonwoven fabric container 3 from the outside. The film 4 is made of a heat-shrinkable material (a material containing a thermoplastic resin) and has a bag shape.

[0041] [Method for Manufacturing Partition Member] Next, a brief description will be given of a method for manufacturing the partition member of this embodiment. The method for manufacturing the partition member 1 includes an insulating sheet housing step and a heat shrinking step. In the insulating sheet housing step, first, an insulating sheet 2 is placed inside the container body 30 shown in FIG. 5 . Next, a lid 31 is welded to the opening of the container body 30. In this manner, the insulating sheet 2 is sealed inside the nonwoven fabric container 3. In the heat shrinking step, first, the nonwoven fabric container 3 containing the insulating sheet 2 is placed inside the film 4 before heat shrinking. Next, the film 4 is heat shrunk to adhere the film 4 to the nonwoven fabric container 3. In this manner, the partition member 1 of this embodiment is manufactured. Then, outside the housing 90 shown in FIG. 1 , cells 92 and partition members 1 are alternately stacked in the front-to-rear direction to create a laminate 91. The laminate 91 is then inserted into the housing 90.

[0042] [Effects] Next, the effects of the partition member of this embodiment will be described. As shown in Figure 5, during normal use, the heat insulating sheet 2 has, along the front-to-rear direction, an ear-set section B (a section in which a part (rear) of the sheet body 20 and the ear 21 are arranged) and a gap-set section C (a section in which the other part (front) of the sheet body 20 and the gap 22 are arranged).

[0043] The gap setting section C has a smaller spring constant in the front-to-rear direction than the ear setting section B by the amount of the gap 22 (the amount of the ear 21 not being provided). Therefore, the partition member 1 can deform in accordance with the deformation (expansion and contraction) of the cells 92.

[0044] 5, during normal use, the gap 22 is continuously maintained in the gap setting section C. That is, the gap 22 is maintained not only when the cell 92 contracts (e.g., during discharge) but also when the cell 92 expands (e.g., during charge).

[0045] In contrast, as shown in Figure 6, even in an abnormal state (when the cells 92 expand or contract abnormally compared to normal use), the ears 21 of the ear-set section B remain interposed between a pair of adjacent cells 92 in the front-to-rear direction. Therefore, even in an abnormal state, contact between the adjacent pair of cells 92 can be suppressed. Therefore, even in an abnormal state, heat transfer between the adjacent pair of cells 92 can be suppressed.

[0046] The heat insulating sheet 2 is a compression-molded product of silica aerogel. Silica aerogel has a higher porosity than other porous materials, which allows for improved heat insulating properties of the heat insulating sheet 2. Furthermore, silica aerogel has excellent chemical stability, so the heat insulating sheet 2 is less likely to deteriorate.

[0047] 4 and 5, in the partition member 1 of this embodiment, the ears 21 and the gaps 22 are arranged so as to overlap in the range A when viewed from the front-to-rear direction. During normal use, a continuous gap is maintained between a pair of adjacent cells 92 in the front-to-rear direction, which reduces the spring constant in the front-to-rear direction.

[0048] On the other hand, as shown in Figure 6, in the event of an abnormality, even if any cell 92 expands in the front-rear direction, the ears 21 can prevent a pair of adjacent cells 92 in the front-rear direction from contacting each other. Therefore, heat transfer from the abnormally heated cell 92 to the surrounding cells 92 can be prevented. In other words, the occurrence of a thermal chain reaction between multiple cells 92 can be prevented.

[0049] As shown in Fig. 5, the partition member 1 of this embodiment can ensure a gap 22 in front of the ear 21 during normal use (a shared gap that absorbs deformation of a pair of cells 92 on both sides in the front-rear direction). Furthermore, the heat insulating sheet 2 has a simple shape. This allows for reduced manufacturing costs for the heat insulating sheet 2.

[0050] As shown in Figure 4, the ear 21 has an endless annular shape when viewed from the front-to-rear direction. This prevents contact between pairs of adjacent cells 92 in the front-to-rear direction around the entire circumference of the partition member 1. As shown in Figures 3 and 5, the heat insulating sheet 2 is an integral unit (single member). This allows for a reduction in the number of parts in the heat insulating sheet 2 and, by extension, the partition member 1, compared to when the heat insulating sheet 2 is a combination of multiple independent members (for example, a combination of the sheet body 20 and the ear 21 that is separate from the sheet body 20). This also reduces manufacturing costs.

[0051] As shown in Figure 5, the heat insulating sheet 2 is doubly contained, from the inside to the outside, in a box-shaped nonwoven fabric container 3 and a bag-shaped film 4. This prevents powder from the heat insulating sheet 2 from leaking out of the partition member 1. The film 4 also forms the outermost layer of the partition member 1. The film 4 helps to maintain the shape of the partition member 1.

[0052] Second Embodiment The partition member of this embodiment differs from the partition member of the first embodiment in that the partition member is composed only of a heat insulating sheet. Here, only the difference will be described. Figure 7 shows a partial cross-sectional view of the partition member of this embodiment in the front-rear direction. Note that parts corresponding to those in Figure 5 are designated by the same reference numerals.

[0053] As shown in Fig. 7, the partition member 1 includes a heat insulating sheet 2. The partition member 1 does not include the nonwoven fabric container 3 and film 4 shown in Fig. 5. The partition member of this embodiment and the partition member of the first embodiment have similar effects with respect to the common configuration parts. According to this embodiment, the number of parts of the partition member 1 can be reduced. Furthermore, the manufacturing cost can be reduced.

[0054] Third Embodiment The partition member of this embodiment differs from the partition member of the first embodiment in that the partition member is composed only of a heat insulating sheet. The heat insulating sheet also has one edge and two gaps. Here, only the differences will be described. Figure 8 shows a partial cross-sectional view of the partition member of this embodiment in the front-rear direction. Note that parts corresponding to those in Figure 5 are designated by the same reference numerals.

[0055] As shown in Figure 8, the partition member 1 includes a heat insulating sheet 2. The partition member 1 does not include the nonwoven fabric container 3 and film 4 shown in Figure 5. The heat insulating sheet 2 includes one ear 21 and two gaps 22. The first gap 22 is located adjacent to the rear cell 92. The second gap 22 is located adjacent to the front cell 92. The ear 21 is located between the first gap 22 and the second gap 22. When viewed from the front-to-rear direction, the ear 21, the gap 22, and the area A each have a rectangular frame shape (endless annular shape).

[0056] The partition member of this embodiment and the partition member of the first embodiment have similar effects with respect to common configuration parts. According to this embodiment, the number of parts of the partition member 1 can be reduced. Furthermore, manufacturing costs can be reduced. Furthermore, according to the partition member 1 of this embodiment, during normal use, a pair of gaps (a first gap 22 that mainly absorbs deformation of the rear cell 92 and a second gap 22 that mainly absorbs deformation of the front cell 92) can be secured on both front and rear sides of the ear portion 21.

[0057] <Fourth embodiment> The partition member of this embodiment differs from the partition member of the first embodiment in that the partition member is composed only of a heat insulating sheet. The heat insulating sheet also has two ears and one gap. Here, only the differences will be described. Figure 9 shows a partial cross-sectional view of the partition member of this embodiment in the front-rear direction. Note that parts corresponding to those in Figure 5 are designated by the same reference numerals.

[0058] As shown in Figure 9, the partition member 1 includes an insulating sheet 2. The partition member 1 does not include the nonwoven fabric container 3 and film 4 shown in Figure 5. The insulating sheet 2 includes two ears 21 and one gap 22. The first ear 21 is located adjacent to the rear cell 92. The second ear 21 is located adjacent to the front cell 92. The gap 22 is located between the first ear 21 and the second ear 21. When viewed from the front-to-rear direction, the ears 21 and the gap 22 each have a rectangular frame shape. As mentioned above, the shape and number of the ears 21 and the gaps 22 are not particularly limited.

[0059] The partition member of this embodiment and the partition member of the first embodiment have similar effects with respect to the common configuration parts. According to this embodiment, the number of parts of the partition member 1 can be reduced. Also, manufacturing costs can be reduced. Furthermore, according to the partition member 1 of this embodiment, during normal use, a gap 22 (a shared gap that absorbs deformation of the pair of cells 92 on both sides in the front-to-rear direction) can be secured midway between the pair of ear portions 21 in the front-to-rear direction.

[0060] Fifth Embodiment The partition member of this embodiment differs from the partition member of the first embodiment in that the partition member is made of only a heat insulating sheet. Also, the edge portion of the heat insulating sheet does not have an endless annular shape. Here, only the differences will be described.

[0061] FIG. 10 shows a front view (front elevation) of the partition member of this embodiment. Note that parts corresponding to those in FIG. 4 are designated by the same reference numerals. For ease of explanation, the outer surface (front surface) of the ear portion 21 is hatched with dashed lines. As shown in FIG. 10, the partition member 1 includes an insulating sheet 2. The partition member 1 does not include the nonwoven fabric container 3 and film 4 shown in FIG. 5. The insulating sheet 2 includes multiple ear portions 21 and one gap 22. Similar to the ear portions 21 shown in FIGS. 3 and 5, the multiple ear portions 21 shown in FIG. 10 are arranged adjacent to the rear cell 92. When viewed from the front-rear direction, the multiple ear portions 21 are arranged intermittently (spaced apart at predetermined intervals) around the entire periphery of the side surface of the sheet body 20. In other words, when viewed from the front-rear direction, the ear portion 21 does not have a rectangular frame shape (endless ring shape). The ear portion 21 has an end shape.

[0062] 3 and 5, the gap 22 shown in Fig. 10 is disposed adjacent to the front cell 92. When viewed from the front-rear direction, the gap 22 has a rectangular frame shape.

[0063] The partition member of this embodiment and the partition member of the first embodiment have similar effects with respect to common configuration parts. According to this embodiment, the number of parts of the partition member 1 can be reduced. Furthermore, manufacturing costs can be reduced. Unlike the partition member 1 of this embodiment, the ear portion 21 does not have to be endless annular. It is sufficient that the ear portion 21 can prevent contact between a pair of cells 92 adjacent in the front-to-rear direction. Specifically, when viewed from the front-to-rear direction, the gap width between a pair of ear portions 21 adjacent in the circumferential direction is sufficient so that the cells 92 cannot enter.

[0064] <Others> The above describes the embodiments of the partition member of the present disclosure. However, the embodiments are not particularly limited to the above embodiments. Various modifications and improvements that can be made by those skilled in the art are also possible.

[0065] [Configuration] At least one of the nonwoven fabric container 3 and the film 4 shown in Fig. 5 may be incorporated into the partition member 1 shown in Figs. 8 to 10. In this way, in the partition member 1 shown in Figs. 8 to 10, it is possible to prevent powder from the heat insulating sheet 2 from leaking out of the partition member 1. It is also possible to maintain the shape of the partition member 1.

[0066] 5 to 10 may further include at least one other layer. For example, an elastic sheet that is more flexible (has a smaller spring constant in the stacking direction) than the heat insulating sheet 2 may be incorporated into the partition member 1. In this case, the elastic force of the elastic sheet can improve the adhesion between the partition member 1 and the cells 92. In addition, deformation (expansion, contraction, etc.) of the cells 92 caused by charging and discharging can be elastically absorbed.

[0067] The partition member 1 may be interposed in the "gaps between pairs of cells 92" of all of the stack 91 shown in Figures 1 and 2. Alternatively, the partition member 1 may be interposed in the "gaps between pairs of cells 92" of only a portion of the stack 91. In this case, a partition member 1 without ears 21 and gaps 22 may be interposed in the "gaps between pairs of cells 92" of the remaining portion of the stack 91. Alternatively, the partition member 1 may be interposed in the gap between the housing 90 and the cell 92.

[0068] The heat insulating sheet 2 may be a single piece, or may be a composite of multiple independent components. When the heat insulating sheet 2 is a composite, the materials and properties of the multiple components may be the same or different. There are no particular limitations on the shapes (shape, position (stacking direction position, layer-side direction position), size, number of arrangement, etc.) of the heat insulating sheet 2 (sheet body 20, ear portions 21, gaps 22), nonwoven fabric container 3, and film 4. For example, the heat insulating sheet 2 may have multiple ear portions 21 and multiple gaps 22 arranged alternately along the stacking direction.

[0069] Furthermore, the shape of the ear 21 when viewed from the stacking direction may be an endless ring or may have ends (for example, a curved shape, a straight shape, or a shape that is a suitable combination of these shapes). When the ear 21 has ends, the arrangement of the ear 21 is not particularly limited. For example, in the front view shown in FIG. 4 , the ear 21 may be arranged in any of the following arrangements (1) to (7): (1) An arrangement in which the ear 21 is arranged on two short sides (left and right sides) of the sheet main body 20; (2) An arrangement in which the ear 21 is arranged on two long sides (top and bottom sides) of the sheet main body 20; (3) An arrangement in which the ear 21 is arranged on one short side (left or right side) of the sheet main body 20; or (4) An arrangement in which the ear 21 is arranged on one long side (top or bottom side) of the sheet main body 20. (5) A configuration in which the ear portions 21 are arranged on one short side (left side or right side) of the seat main body 20 and one long side (top side or bottom side) of the seat main body 20. (6) A configuration in which the ear portions 21 are arranged on two short sides (left side and right side) of the seat main body 20 and one long side (top side or bottom side) of the seat main body 20. (7) A configuration in which the ear portions 21 are arranged on one short side (left side or right side) of the seat main body 20 and two long sides (top side and bottom side) of the seat main body 20.

[0070] The degree of overlap between the gap 22 and the ear portion 21 when viewed from the stacking direction is not particularly limited. The gap 22 and the ear portion 21 may completely overlap. Alternatively, the gap 22 and the ear portion 21 may partially overlap.

[0071] As shown in Fig. 5, other members or parts (part of the container body 30, part of the film 4) may be disposed in the gap 22. As shown in Figs. 7 to 9, other members or parts do not have to be disposed in the gap 22. It is sufficient that the gap 22 is continuously secured during normal use. In other words, it is sufficient that the gap 22 is able to absorb the amount of deformation of the cell 92 during normal use.

[0072] The stacking direction of the partition members 1 and the cells 92 in the laminate 91 is not particularly limited. It may be horizontal (front-rear or left-right), vertical (up-down), or inclined relative to these directions. The shape of the housing 90 is not particularly limited. For example, the housing 90 may include a pair of front and rear end plates and a pair of left and right tie rods connecting the pair of end plates. The type of the cells 92 is not particularly limited. It may be a rectangular cell, a cylindrical cell, a laminated cell, or the like. The type of secondary battery is not particularly limited. It may be a lithium-ion secondary battery, a lithium-ion polymer secondary battery, a sodium-ion secondary battery, a nickel-metal hydride secondary battery, or the like. The use of the battery module 9 is not particularly limited. For example, it may be used in hybrid vehicles, electric vehicles, etc. It may also be used in electrically assisted bicycles, mobile phones, power tools, laptops, etc.

[0073] [Regarding materials] There are no particular restrictions on the material of the heat insulating sheet 2. There are no particular restrictions on the type of granular porous material for the heat insulating sheet 2. Examples of primary particles include silica, alumina, zirconia, and titania. Of these, silica aerogel, in which the primary particles are silica, i.e., a skeleton formed by linking multiple silica fine particles, is preferred because of its excellent chemical stability. Also preferred is an agglomerated structure in which a skeleton formed by linking multiple fumed silica fine particles.

[0074] The method for producing silica aerogel is not particularly limited. The drying process may be performed at normal pressure or supercritical. For example, if a hydrophobic treatment is performed before the drying process, supercritical drying is not necessary. In other words, drying at normal pressure is sufficient, making production easier and less costly. Depending on the drying method used in producing aerogel, aerogels dried at normal pressure are sometimes called "xerogels" and aerogels dried at supercritical pressure are sometimes called "aerogels." In this specification, however, both are referred to as "aerogels."

[0075] In addition to the granular porous material, the heat insulating sheet 2 may contain infrared-shielding particles, inorganic fibers, etc. The infrared-shielding particles absorb heat from a heat source and re-emit it from the surface facing the heat source, thereby blocking radiant heat from the heat source and contributing to improved heat insulation, particularly at high temperatures. Examples of infrared-shielding particles include silicon carbide, kaolinite, montmorillonite, silicon nitride, mica, alumina, zirconia, aluminum nitride, titanium oxide, zirconium silicate, zinc oxide, tantalum oxide, tungsten oxide, niobium oxide, indium tin oxide, cerium oxide, boron carbide, manganese oxide, tin oxide, bismuth oxide, iron oxide, magnesium oxide, and barium titanate. Ceramic fibers such as glass fibers and alumina fibers are suitable as inorganic fibers.

[0076] There are no particular limitations on the material of the nonwoven fabric container 3. It may be made of glass fiber, rock wool, ceramic fiber, polyimide (PI) fiber, polyphenylene sulfide (PPS) fiber, or the like.

[0077] The material of the film 4 is not particularly limited. When a shrink film is used for at least a portion of the film 4, the material of the shrink film may be polyvinyl chloride (PVC), polypropylene (PP), polyethylene (PE), polystyrene (PS), polyethylene terephthalate (PET), or the like. The film 4 may also be a film other than a shrink film. It may also be a resin film that does not contain a thermoplastic resin. For example, it may be a bag-shaped film for vacuum packing. The material of the housing 90 and the case 921 is not particularly limited. For example, it may be a resin such as polypropylene, or a metal such as steel, aluminum, or an aluminum alloy.

[0078] 1: Partition member, 2: Heat insulating sheet, 20: Sheet body, 21: Edge portion, 22: Gap, 3: Nonwoven fabric container, 4: Film, 9: Battery module, 30: Container body, 31: Lid, 90: Housing, 91: Laminated body, 92: Cell, 920: Terminal, 921: Case, 922: Contents, A: Non-contact area, B: Edge portion setting section, C: Gap setting section

Claims

1. A partition member comprising an insulating sheet interposed between any pair of cells adjacent in the stacking direction in a stack of multiple cells, wherein a direction intersecting the stacking direction is defined as a layer direction, and normal use refers to the time when the cells deform due to normal charging and discharging, and the insulating sheet has a sheet body and ear portions protruding outward in the layer direction from the sheet body, and during normal use, a gap is secured on the outer side of the sheet body in the layer direction that overlaps with the ear portions when viewed from the stacking direction.

2. A partition member according to claim 1, wherein the ear portion is disposed adjacent to the cells on one side of the stacking direction, and the gap is disposed adjacent to the cells on the other side of the stacking direction.

3. A partition member according to claim 1 or claim 2, wherein the ear portion has an endless annular shape when viewed in the stacking direction.

4. A partition member according to claim 1 or claim 2, wherein the ear portion has an end when viewed from the stacking direction.

5. A partition member according to any one of claims 1 to 4, wherein the heat insulating sheet is a single piece.

6. A partition member according to any one of claims 1 to 4, wherein the heat insulating sheet is a combination of a plurality of independent members.

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