Partition member

Abstract

To provide a partition member that can suppress a decrease in heat insulating properties.SOLUTION: A partition member 1 is interposed between any pair of cells 92 adjacent in the stacking direction in a stack 91 of multiple cells 92. The partition member 1 includes a thermal insulation layer 2, spacer layers 5, 5a made of a material different from that of the thermal insulation layer 2 and interposed between the thermal insulation layer 2 and the cells 92, and penetration suppression layers 6, 6a interposed between the thermal insulation layer 2 and the spacer layers 5, 5a and suppressing the material forming the spacer layers 5, 5a from penetrating into the thermal insulation layer 2.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a partition member disposed in a stack of battery modules. [Background technology]

[0002] In the battery pack of Patent Document 1, a porous heat insulating layer is interposed between a pair of cells adjacent to each other in the stacking direction to suppress heat transfer between the pair of cells. In the assembled battery of Patent Document 2, a resin frame is interposed between a pair of cells adjacent to each other in the stacking direction to suppress positional variations in the cell terminals. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2021-144879 [Patent Document 2] Patent Publication No. 2021-34151 Summary of the Invention [Problem to be solved by the invention]

[0004] Consider a case in which a partition member having both the above-described insulating layer and resin frame is interposed between a pair of adjacent cells in the stacking direction. In this case, if the material forming the resin frame melts and liquefies due to abnormal heat generation in the cells, the liquefied material may penetrate the pores of the insulating layer, impairing the porosity of the insulating layer. In other words, the insulating properties of the insulating layer may be reduced. Therefore, an object of the present disclosure is to provide a partition member that can suppress the reduction in insulating properties. [Means for solving the problem]

[0005] (1) In order to solve the above problem, the partition member of the present disclosure is a partition member interposed between any pair of adjacent cells in the stacking direction in a stack of multiple cells, and is characterized by comprising an insulating layer, a spacer layer interposed between the insulating layer and the cell and made of a material different from the insulating layer, and a penetration suppression layer interposed between the insulating layer and the spacer layer and suppressing the material from penetrating into the insulating layer.

[0006] According to this configuration, the layers of the laminate are stacked in the following order in the stacking direction: cell, spacer layer, permeation suppression layer, and insulating layer. That is, the permeation suppression layer is interposed between the spacer layer and the insulating layer. This prevents the material forming the spacer layer from permeating into the insulating layer. Therefore, even if the material forming the spacer layer liquefies, the liquefied material (hereinafter referred to as "liquefied material") can be prevented from penetrating from the spacer layer into the insulating layer via the permeation suppression layer. This prevents a decrease in the insulating properties of the insulating layer.

[0007] (1-1) In the above-mentioned configuration (1), it is preferable that the material forming the spacer layer is a thermoplastic resin or a metal. With this configuration, even if the material forming the spacer layer melts and liquefies, the liquefied material can be prevented from seeping into the heat insulating layer.

[0008] (1-2) In any of the above configurations, it is preferable that the melting point of the material forming the spacer layer is lower than the temperature of the cell when abnormal heat generation occurs. With this configuration, even if the material forming the spacer layer melts and liquefies due to abnormal heat generation in the cell, the liquefied material can be prevented from seeping into the heat insulating layer.

[0009] (1-3) In any of the above configurations, it is preferable that the melting point of the material forming the penetration suppression layer is higher than the temperature when the cell abnormally heats up. According to this configuration, even if the material forming the spacer layer melts and liquefies due to abnormal heat generation in the cell, the penetration suppression layer can maintain its structure and characteristics. Therefore, it is possible to suppress the liquefied material from penetrating into the heat insulating layer.

[0010] (2) In any of the above configurations, the heat insulating layer is preferably a compression-molded product of a granular porous material, which is a porous body formed from a granular substance. A compression-molded product of a granular porous material has many pores inside, and gas (such as air) is retained in the pores. Therefore, with this configuration, the heat insulating property of the heat insulating layer can be improved.

[0011] (3) In any of the above configurations, the material forming the spacer layer is preferably polypropylene, polyethylene, aluminum, aluminum alloy, phenolic resin, polyacetal, acrylic, or a fiber-reinforced product of any of these materials. This configuration reduces the manufacturing cost of the spacer layer. Furthermore, the spacer layer requires a certain rigidity to ensure the restraining force (pressure in the stacking direction) applied to the cells. This configuration makes it possible to easily ensure this rigidity.

[0012] (4) In any of the above configurations, the penetration suppression layer is preferably made of a porous material. With this configuration, the porosity of the penetration suppression layer can be utilized to absorb at least a portion of the liquefied material, thereby preventing the liquefied material from penetrating into the insulating layer.

[0013] (5) In the configuration of (4) above, it is preferable that the porous material be glass fiber paper, Bakelite paper, carbon fiber paper, or ceramic fiber paper. All of these materials have excellent heat resistance. Therefore, even if the material of the spacer layer melts or liquefies, the permeation suppression layer can maintain its porosity. Therefore, the permeation suppression layer can reliably absorb the liquefied material. Furthermore, the manufacturing cost of the permeation suppression layer can be reduced. [Effects of the Invention]

[0014] According to the partition member of the present disclosure, it is possible to suppress a decrease in heat insulating properties. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is an exploded perspective view of a battery module including a partition member according to a first embodiment. [Figure 2] FIG. 2 is a top view of the battery module. [Figure 3] FIG. 3 is a cross-sectional view in the front-rear direction within a frame III in FIG. [Figure 4] FIG. 4 is an enlarged view of the area within the frame IV in FIG. [Figure 5] FIG. 5 is an enlarged view of the area within the frame V in FIG. [Figure 6] FIG. 6 is a partial cross-sectional view in the front-rear direction of a partition member that does not include a penetration suppression layer. [Figure 7] FIG. 7 is a partial cross-sectional view in the front-rear direction of a partition member of the second embodiment. [Figure 8] FIG. 8 is a partial cross-sectional view in the front-rear direction of a partition member of the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an embodiment of the partition member of the present disclosure will be described.

[0017] First Embodiment In the following figures, the front-rear direction corresponds to the "stacking direction" in the present disclosure. 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 front-rear cross-sectional view of the area within frame III in Fig. 2. Fig. 4 shows an enlarged view of the area within frame IV in Fig. 3. Fig. 5 shows an enlarged view of the area within frame V in Fig. 4.

[0018] [Layout and configuration of partition members] First, the arrangement and configuration of the partition member of this embodiment will be described. The partition member 1 of this embodiment is incorporated into a battery module 9 of an electric vehicle (a vehicle that runs solely on electricity, not a hybrid). As shown in Figures 1 and 2, the battery module 9 includes a housing 90 and a laminated body 91.

[0019] The housing 90 has a box 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.

[0020] As shown in FIGS. 1 to 3, the cells 92 have a flat rectangular parallelepiped shape extending in the up-down and left-right directions (vertical directions, orthogonal to the stacking direction). That is, the cells 92 are prismatic cells. The cells 92 include two terminals 920, a case 921, and contents 922 (schematically shown in the figures). The terminals 920 of adjacent cells 92 in the front-rear direction are electrically connected to each other by a bus bar (not shown).

[0021] 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. The partition member 1 has a flat plate shape extending in the up-down and left-right directions.

[0022] As shown in Figures 3 to 5, the partition member 1 includes a heat insulating layer 2, a nonwoven fabric container 3, a film 4, a spacer layer 5, and a penetration suppression layer 6. The heat insulating layer 2 is a compression-molded product of silica aerogel. Silica aerogel is included in the concept of "granular porous material" in this disclosure. The heat insulating layer 2 is flat.

[0023] As shown in Figures 3 to 5, the spacer layer 5 is made of a thermoplastic resin (polypropylene) and has a flat plate shape. That is, the spacer layer 5 is made of a different material from the heat insulating layer 2. The spacer layer 5 is disposed on the front side (one side of the stacking direction) of the heat insulating layer 2, with a penetration suppression layer 6 and a nonwoven fabric container 3 (described later) interposed therebetween. The spacer layer 5 is also disposed on the rear side (the other side of the stacking direction) of the front cell 92 (the front cell 92 of a pair of front and rear cells 92) interposed therebetween (described later). That is, the spacer layer 5 is interposed between the rear heat insulating layer 2 and the front cell 92.

[0024] As shown in Figures 3 to 5, the penetration suppression layer 6 is made of a porous material (glass fiber paper) and has a flat plate shape. As shown schematically in Figure 5, the penetration suppression layer 6 has a large number of pores 60 inside. The penetration suppression layer 6 is disposed on the front side of the heat insulating layer 2. The penetration suppression layer 6 is also disposed on the rear side of the spacer layer 5, with a nonwoven fabric container 3 (described later) in between. In other words, the penetration suppression layer 6 is interposed between the rear heat insulating layer 2 and the front spacer layer 5. As described later, the penetration suppression layer 6 suppresses the material forming the spacer layer 5 from penetrating into the heat insulating layer 2.

[0025] As shown in Figures 3 to 5, the nonwoven fabric container 3 covers the heat insulating layer 2 from the outside. The nonwoven fabric container 3 is made of nonwoven fabric and includes a container body 30 and a lid 31. The container body 30 is in the shape of a rectangular box (bag) that opens toward the rear. Inside the container body 30, from the rear side (the opening side of the container body 30) to the front side (the bottom wall side of the container body 30), the heat insulating layer 2 and the permeation suppression layer 6 are housed. The permeation suppression layer 6 abuts against the inner surface (rear surface) of the bottom wall of the container body 30. The lid 31 seals the opening of the container body 30 from the rear side. 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 is in the shape of a bag.

[0026] [Manufacturing method of partition member] Next, a brief description will be given of a manufacturing method of the partition member of this embodiment. The manufacturing method of the partition member 1 includes a container placement step and a heat shrinking step. In the container placement step, first, the permeation suppression layer 6 and the heat insulating layer 2 are arranged from front to rear inside the container body 30 shown in FIGS. 3 and 4. Next, the lid 31 is welded to the opening of the container body 30. In this way, the permeation suppression layer 6 and the heat insulating layer 2 are sealed inside the nonwoven fabric container 3. In the heat shrinking step, first, the spacer layer 5 and the nonwoven fabric container 3 containing the permeation suppression layer 6 and the heat insulating layer 2 are arranged from front to rear inside the film 4 before heat shrinking. Next, the film 4 is heat shrunk to adhere the film 4 to the spacer layer 5 and the nonwoven fabric container 3. In this way, the partition member 1 of this embodiment is manufactured. Thereafter, outside the housing 90 shown in FIG. 1, the cells 92 and the partition members 1 are alternately stacked in the front-to-rear direction to form a laminate 91. Then, the stack 91 is inserted into the housing 90 .

[0027] [Action and effect] Next, the effects of the partition member of this embodiment will be described. As shown in Figures 3 to 5, the partition member 1 includes spacer layers 5. By adjusting the number of spacer layers 5 arranged in the laminate 91 and the thickness in the front-rear direction, it is possible to adjust the restraining force (pressure force in the front-rear direction) applied from the housing 90 to the cells 92 of the laminate 91.

[0028] Fig. 6 shows a partial cross-sectional view in the front-rear direction of a partition member that does not have a penetration suppression layer. The portion shown in Fig. 6 corresponds to the area within frame V in Figs. 4 and 5. The partition member shown in Fig. 6 has a spacer layer 5. The partition member does not have the penetration suppression layer 6 shown in Fig. 5.

[0029] Let us consider a case in which the front cell 92 of the pair of front and rear cells 92 shown in Figure 6 generates abnormal heat. The material forming the spacer layer 5 is a thermoplastic resin (polypropylene). Therefore, if the melting point of the material forming the spacer layer 5 (approximately 160°C in the case of polypropylene) is lower than the temperature of the cell 92 at the time of abnormal heat generation, the material forming the spacer layer 5 will melt and liquefy due to the abnormal heat generation of the front cell 92. As a result, the liquefied material will penetrate the container body 30 and soak into the heat insulating layer 2.

[0030] Here, the insulating layer 2 has many pores (not shown) inside. The insulating layer 2 ensures its thermal insulation properties due to its own porosity. The liquefied material that has soaked into the insulating layer 2 enters the pores of the insulating layer 2. This reduces the insulating properties of the insulating layer 2. Therefore, as shown schematically in Figure 6, a heat transfer path L is formed between the front cell 92 and the inside of the insulating layer 2 (the part where the liquefied material has soaked). The heat transfer path L has a higher thermal conductivity than other parts of the insulating layer 2 (the parts where the liquefied material has not soaked). Therefore, the heat of the front cell 92 is easily transferred via the heat transfer path L to the inside of the insulating layer 2, and ultimately to the rear cell 92.

[0031] 6 (a partition member provided with the spacer layer 5 and not the penetration suppression layer 6), when any cell 92 generates abnormal heat, the heat is likely to be transferred to another cell 92 adjacent to the cell 92 across the partition member. In other words, when abnormal heat is generated, a thermal chain reaction is likely to occur between adjacent cells 92.

[0032] In this regard, as shown in FIGS. 4 and 5 , the partition member 1 of this embodiment includes a permeation suppression layer 6 in addition to a spacer layer 5. The layers of the laminate 91 are stacked in the following order from the front side (one side of the stacking direction) to the rear side (the other side of the stacking direction): front cells 92, film 4, spacer layer 5, container body 30, permeation suppression layer 6, and heat insulating layer 2. That is, the permeation suppression layer 6 is interposed between the spacer layer 5 and the heat insulating layer 2. Therefore, even if abnormal heat generation in the front cells 92 melts and liquefies the material (polypropylene) forming the spacer layer 5, and the liquefied material penetrates the container body 30, the permeation of the liquefied material into the heat insulating layer 2 can be suppressed. Therefore, the occurrence of a thermal chain reaction between adjacent cells 92 during abnormal heat generation can be suppressed.

[0033] More specifically, the liquefied material that penetrates the container body 30 penetrates into the penetration suppression layer 6. As shown in FIG. 5, the penetration suppression layer 6 has a large number of pores 60 therein. At least a portion of the liquefied material that penetrates into the penetration suppression layer 6 is absorbed and captured by the pores 60. This prevents the liquefied material from penetrating the penetration suppression layer 6. This also prevents the liquefied material from penetrating into the insulating layer 2. This prevents a decrease in the insulating properties of the insulating layer 2.

[0034] In this way, according to the partition member 1 of this embodiment, the problem specific to partition members 1 that have a spacer layer 5 (the problem that the material forming the spacer layer 5 may seep into the insulating layer 2) can be solved by the seepage prevention layer 6.

[0035] The heat insulating layer 2 is a compression molded product of silica aerogel. Silica aerogel has a higher porosity than other porous materials. This allows the heat insulating layer 2 to have high heat insulating properties. In addition, silica aerogel has excellent chemical stability, so the heat insulating layer 2 is less likely to deteriorate.

[0036] The spacer layer 5 is made of polypropylene, which reduces the manufacturing cost of the spacer layer 5. The spacer layer 5 is also required to have a certain rigidity in order to ensure the binding force (pressure in the front-rear direction) applied to the cells 92. In this regard, since the spacer layer 5 is made of polypropylene, this rigidity can be easily ensured.

[0037] The permeation suppression layer 6 is made of a porous material (glass fiber paper). This provides excellent heat resistance. The melting point of the porous material forming the permeation suppression layer 6 is higher than the temperature of the cells 92 during abnormal heat generation. Therefore, even if the material forming the spacer layer 5 melts and liquefies, the permeation suppression layer 6 can maintain its structure and characteristics. For example, the permeation suppression layer 6 can maintain its porosity. Therefore, the permeation suppression layer 6 can reliably absorb the liquefied material. Furthermore, because glass fiber paper is inexpensive, the manufacturing cost of the permeation suppression layer 6 can be reduced.

[0038] As shown in Figures 3 and 4, the heat insulating layer 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 layer 2 from leaking out of the partition member 1. The film 4 also constitutes the outermost layer of the partition member 1. The film 4 allows the partition member 1 to maintain its shape.

[0039] As shown in Figures 3 and 4, the spacer layer 5 is disposed outside the nonwoven fabric container 3. The penetration suppression layer 6 is disposed inside the nonwoven fabric container 3 together with the heat insulating layer 2. In other words, the penetration suppression layer 6 and the heat insulating layer 2 are separated from the spacer layer 5 by the nonwoven fabric container 3. This makes it possible to prevent the material forming the spacer layer 5 from penetrating into the heat insulating layer 2.

[0040] 3 and 4, the spacer layer 5 is disposed outside the nonwoven fabric container 3. Therefore, compared to when the spacer layer 5 is disposed inside the nonwoven fabric container 3, the spacer layer 5 can be changed without being restricted by the volume of the nonwoven fabric container 3. For example, any spacer layer 5 can be freely changed to another spacer layer 5 having a different thickness in the front-to-rear direction.

[0041] The battery module 9 of an electric vehicle (a vehicle that runs solely on electricity, not a hybrid) has a larger capacity than the battery module of a hybrid vehicle. For this reason, the cells 92 of the battery module 9 of an electric vehicle are more likely to generate abnormal heat than the cells 92 of the battery module of a hybrid vehicle.

[0042] In this regard, the partition member 1 of this embodiment is incorporated into the battery module 9 of an electric vehicle. Therefore, in an electric vehicle, which is more prone to abnormal heat generation than a hybrid vehicle, it is possible to suppress the occurrence of a thermal chain reaction between adjacent cells 92. In this way, the partition member 1 of this embodiment is suitable for incorporation into the battery module 9 of an electric vehicle.

[0043] 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 layer, a spacer layer, and a penetration suppression layer. Here, only the differences will be described. Fig. 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 Fig. 4 are designated by the same reference numerals. The parts shown in Fig. 7 correspond to those in box IV in Figs. 3 and 4.

[0044] As shown in Fig. 7, the partition member 1 includes, from the front to the rear, a spacer layer 5, a permeation suppression layer 6, and a heat insulating layer 2. The partition member 1 does not include the nonwoven fabric container 3 and film 4 shown in Fig. 4. The spacer layer 5 and the permeation suppression layer 6 abut against each other. The spacer layer 5 and the permeation suppression layer 6 are laminated directly on top of each other without any other layer or member in between.

[0045] The partition member 1 of this embodiment and the partition member of the first embodiment have the same effects as those of the first embodiment in terms of the common configuration. According to this embodiment, the number of parts of the partition member 1 can be reduced. In addition, the manufacturing cost can be reduced.

[0046] As in this embodiment, the spacer layer 5 and the penetration suppression layer 6 may be laminated directly without any other layers or members in between. In this way, even if the material forming the spacer layer 5 liquefies, the liquefied material can be absorbed in the immediate vicinity of the spacer layer 5. Therefore, diffusion of the liquefied material originating from the spacer layer 5 can be suppressed.

[0047] Third Embodiment The partition member of this embodiment differs from the partition member of the first embodiment in that the partition member includes a plurality of spacer layers and a plurality of penetration suppression layers. Here, only the differences will be described. Fig. 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 Fig. 4 are designated by the same reference numerals. The parts shown in Fig. 8 correspond to those in box IV in Figs. 3 and 4.

[0048] As shown in Fig. 8, the partition member 1 includes a pair of front and rear spacer layers 5, 5a and a pair of front and rear permeation suppression layers 6, 6a. The pair of front and rear spacer layers 5, 5a have the same configuration. The pair of front and rear permeation suppression layers 6, 6a have the same configuration. The configuration and arrangement of the front spacer layer 5 and permeation suppression layer 6 are the same as the configuration and arrangement of the spacer layer 5 and permeation suppression layer 6 shown in Fig. 4.

[0049] The rear spacer layer 5a is disposed on the rear side (the other side of the stacking direction) of the heat insulating layer 2, via the nonwoven fabric container 3 and a rear penetration suppression layer 6a (described later). The spacer layer 5a is also disposed on the front side (one side of the stacking direction) of the rear cell 92 (the rear cell 92 of the pair of front and rear cells 92) via the film 4. In other words, the spacer layer 5a is interposed between the front heat insulating layer 2 and the rear cell 92.

[0050] The rear permeation suppression layer 6a is disposed behind the heat insulating layer 2. The permeation suppression layer 6a is disposed in front of the spacer layer 5a, with the nonwoven fabric container 3 interposed between them. That is, the permeation suppression layer 6a is interposed between the front heat insulating layer 2 and the rear spacer layer 5a. The permeation suppression layer 6a suppresses the material forming the spacer layer 5a from permeating into the heat insulating layer 2.

[0051] The partition member of this embodiment and the partition member of the first embodiment have the same effects as those of the first embodiment in the parts that share the same configuration. According to this embodiment, the plurality of penetration suppression layers 6, 6a are arranged corresponding to the plurality of spacer layers 5, 5a, respectively. Therefore, even if the material forming at least one of the plurality of spacer layers 5, 5a is liquefied, the liquefied material can be absorbed.

[0052] Furthermore, in this embodiment, multiple penetration suppression layers 6, 6a are arranged on both front and rear sides of the insulating layer 2. Specifically, the front penetration suppression layer 6 covers the front surface of the insulating layer 2. In addition, the rear penetration suppression layer 6a covers the rear surface of the insulating layer 2. This makes it possible to suppress the liquefied material forming the spacer layers 5, 5a from penetrating into the insulating layer 2 not only from one front-to-rear side but also from both front-to-rear sides (i.e., from at least one of the front-to-rear sides).

[0053] <Other> 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.

[0054] [About the configuration] The nonwoven fabric container 3 or film 4 shown in Fig. 4 may be incorporated into the partition member 1 shown in Fig. 7. In this way, in the partition member 1 shown in Fig. 7, it is possible to prevent powder from the heat insulating layer 2 from leaking out of the partition member 1. It is also possible to maintain the shape of the partition member 1.

[0055] The positional relationship between the spacer layers 5, 5a and the permeation suppression layers 6, 6a and the nonwoven fabric container 3 is not particularly limited. For example, the spacer layers 5, 5a may be disposed on the outside of the nonwoven fabric container 3, and the permeation suppression layers 6, 6a may be disposed on the inside of the nonwoven fabric container 3. That is, the spacer layers 5, 5a and the permeation suppression layers 6, 6a may be disposed separately on the inside and outside of the nonwoven fabric container 3. Alternatively, the spacer layers 5, 5a and the permeation suppression layers 6, 6a may all be disposed inside the nonwoven fabric container 3. Alternatively, the spacer layers 5, 5a and the permeation suppression layers 6, 6a may all be disposed outside the nonwoven fabric container 3. The same applies to the positional relationship between the spacer layers 5, 5a and the permeation suppression layers 6, 6a and the film 4.

[0056] 4, 7, and 8 may further include at least one other layer. For example, an elastic layer that is more flexible (has a smaller spring constant in the front-to-rear direction) than the insulating layer 2 may be incorporated into the partition member 1. In this case, the elastic force of the elastic layer 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.

[0057] The partition member 1 may be interposed in the "gaps between a pair 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 a pair of cells 92" of only a part of the stack 91. Alternatively, the partition member 1 may be interposed in the gap between the housing 90 and the cell 92.

[0058] The spacer layers 5, 5a shown in Figures 4, 7, and 8 may be disposed on all of the partition members 1 of the laminate 91 shown in Figures 1 and 2. Alternatively, the partition members 1 may be disposed on only some of the partition members 1 of the laminate 91.

[0059] There is no particular limit to the number of spacer layers 5, 5a arranged in a single laminate 91. As shown in Fig. 4, the laminate 91 has a plurality of "gaps between the cells 92 and the heat insulating layer 2." Spacer layers 5, 5a may be arranged in all of the plurality of gaps. Spacer layers 5, 5a may also be arranged in some of the plurality of gaps.

[0060] There is no particular limit to the number of permeation suppression layers 6, 6a arranged in a single laminate 91. As shown in Fig. 4, the laminate 91 has a plurality of "gaps between the spacer layers 5, 5a and the heat insulating layer 2." Permeation suppression layers 6, 6a may be arranged in all of the plurality of gaps. Alternatively, permeation suppression layers 6, 6a may be arranged in some of the plurality of gaps.

[0061] There is no particular limit to the number of penetration suppression layers 6, 6a arranged on a single spacer layer 5, 5a. A pair of penetration suppression layers 6, 6a may be arranged on both front-to-rear sides of the spacer layer 5, 5a. A single penetration suppression layer 6, 6a may be arranged on one front-to-rear side of the spacer layer 5, 5a. In other words, the penetration suppression layer 6, 6a may be arranged on one of the front-to-rear sides of the spacer layer 5, 5a in the direction in which it is desired to suppress the outflow of the material that forms the spacer layer 5, 5a.

[0062] There is no particular limit to the number of penetration suppression layers 6, 6a arranged for a single thermal insulation layer 2. A pair of penetration suppression layers 6, 6a may be arranged on both front-to-rear sides of the thermal insulation layer 2. A single penetration suppression layer 6, 6a may be arranged on one front-to-rear side of the thermal insulation layer 2. In other words, the penetration suppression layer 6, 6a may be arranged on one of the front-to-rear sides of the thermal insulation layer 2 in the direction in which it is desired to suppress the inflow of the material that forms the spacer layers 5, 5a.

[0063] The cause of liquefaction of the material forming the spacer layers 5, 5a is not particularly limited. The cause of liquefaction varies depending on the properties of the material forming the spacer layers 5, 5a (described later). Examples of the cause include melting, thermal decomposition, and hydrolysis of the material.

[0064] The liquid to be absorbed by the penetration suppression layers 6, 6a is not particularly limited to liquid derived from the material forming the spacer layers 5, 5a. For example, it may be liquid derived from the material forming the heat insulating layer 2 or liquid derived from the environment (temperature, humidity, etc.) in which the battery module 9 is placed.

[0065] The stacking direction of the partition members 1 and the cells 92 in the stack 91 is not particularly limited. It may be horizontal (front-rear or left-right), vertical (up-down), or a direction 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 (restraint members) connecting the pair of end plates. The type of the cells 92 is not particularly limited. They may be prismatic cells, cylindrical cells, laminated cells, etc. The type of secondary battery is not particularly limited. They may be lithium-ion secondary batteries, lithium-ion polymer secondary batteries, sodium-ion secondary batteries, nickel-metal hydride secondary batteries, etc. The use of the battery module 9 is not particularly limited. For example, it may be used in electric vehicles, hybrid vehicles, etc. It may also be used in electrically assisted bicycles, mobile phones, power tools, laptops, etc.

[0066] [About the materials] The material of the heat insulating layer 2 is not particularly limited. The type of granular porous material for the heat insulating layer 2 is not particularly limited. Examples of primary particles include silica, alumina, zirconia, and titania. Among 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.

[0067] 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."

[0068] In addition to the granular porous material, the heat insulating layer 2 may contain infrared-shielding particles, inorganic fibers, etc. The infrared-shielding particles absorb heat from the 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. Suitable inorganic fibers include ceramic fibers such as glass fibers and alumina fibers.

[0069] 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, polyethylene terephthalate (PET) fiber, or the like.

[0070] The material of film 4 is not particularly limited. When a shrink film is used for at least a portion of 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. Film 4 may also be a film other than 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 housing 90 and 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.

[0071] The material of the spacer layers 5, 5a is not particularly limited. For example, it may be a thermoplastic resin, a thermosetting resin, a reinforced resin thereof (e.g., PA6-GF30), or a metal. Examples of thermoplastic resins include vinyl chloride, polypropylene, polyethylene, polystyrene, polyethylene terephthalate, polyamide (PA), polytetrafluoroethylene (PTFE), acrylonitrile butadiene styrene resin (ABS), polyacetal (POM), and acrylic resin. Examples of thermosetting resins include epoxy resin (EP), phenolic resin (PF), silicone resin, and unsaturated polyester resin (UP). Examples of metals include aluminum, aluminum alloys, and steel (specifically, hot-rolled steel sheet, cold-rolled steel sheet, stainless steel sheet, etc.). Various materials can be used depending on the specifications of the battery module 9.

[0072] The material of the penetration suppression layers 6, 6a is not particularly limited. The penetration suppression layers 6, 6a may be porous or non-porous. When the penetration suppression layers 6, 6a are porous, that is, when the penetration suppression layers 6, 6a have a liquefied material absorption function (a function of absorbing the liquefied material and thereby suppressing the liquefied material from penetrating into the thermal insulation layer 2), examples of materials for the penetration suppression layers 6, 6a include glass fiber (glass fiber paper), paper Bakelite, cloth Bakelite, rock wool, glass wool, ceramic fiber, polyimide fiber, and polyphenylene sulfide fiber.

[0073] When the penetration suppression layers 6, 6a are not porous, that is, when the penetration suppression layers 6, 6a have a liquefied material blocking function (the function of blocking the liquefied material and thereby preventing the liquefied material from penetrating into the insulating layer 2), materials for forming the penetration suppression layers 6, 6a include, for example, solid (non-porous) resins and metals. [Explanation of symbols]

[0074] 1: Partition member, 2: Heat insulating layer, 3: Nonwoven fabric container, 4: Film, 5: Spacer layer, 5a: Spacer layer, 6: Penetration suppression layer, 6a: Penetration suppression layer, 9: Battery module, 30: Container body, 31: Lid, 90: Housing, 91: Laminated body, 92: Cell, 920: Terminal, 921: Case, 922: Contents, L: Heat transfer path

Claims

1. A partition member interposed between any pair of adjacent cells in a stack of multiple cells, A thermal insulation layer; a spacer layer interposed between the insulating layer and the cell and made of a material different from that of the insulating layer; a penetration suppression layer interposed between the heat insulating layer and the spacer layer to suppress penetration of the material into the heat insulating layer; A partition member comprising:

2. 2. The partition member according to claim 1, wherein the heat insulating layer is a compression molded product of a granular porous material, which is a porous body formed from granular substances.

3. 2. The partition member according to claim 1, wherein the material forming the spacer layer is any one of polypropylene, polyethylene, aluminum, aluminum alloy, phenolic resin, polyacetal, acrylic, and a fiber-reinforced product of any one of these materials.

4. The partition member according to claim 1 , wherein the penetration suppression layer is made of a porous material.

5. 5. The partition member according to claim 4, wherein the porous material is any one of glass fiber paper, Bakelite paper, carbon fiber paper, and ceramic fiber paper.

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