Heat transfer suppression member and battery pack

Abstract

To provide a heat transfer suppression member that maintains the distance between battery cells, can prevent the destruction of a battery case due to deformation of the battery cells, can reduce the deterioration of battery performance, and can secure desired heat insulation properties at an abnormal time.SOLUTION: A heat transfer suppression member 180 has: a frame 53 that forms part of the outer circumference in a plan view; and plate-shaped first heat insulating material 10a and second heat insulating material 10b, each of which has a pair of main surfaces 10s and an end surface 10e that is approximately orthogonal to the main surfaces 10s. The frame 53 has an outer end face 53e that is parallel to the end faces 10e of the first heat insulating material 10a and second heat insulating material 10b. At least parts of the first heat insulating material 10a and second heat insulating material 10b are arranged inside the frame 53 so that the exposed end surface 10e of the insulation material in an area where the frame 53 does not exist on the outer circumference is flush with at least part of the outer end surface 53e of the frame 53 in plan view or protrudes from at least part of the outer end surface 53e of the frame 53.SELECTED DRAWING: Figure 1A

Description

[Technical field]

[0001] The present invention relates to a heat transfer suppressing member and a battery pack having the heat transfer suppressing member. [Background technology]

[0002] In recent years, from the viewpoint of environmental protection, active development of electric vehicles, hybrid vehicles, etc. that are driven by electric motors is underway. These electric vehicles, hybrid vehicles, etc. are equipped with assembled batteries in which multiple battery cells are connected in series or parallel to serve as the power source for the driving electric motor.

[0003] In addition, lithium-ion secondary batteries, which have higher capacity and higher output than lead-acid batteries, nickel-metal hydride batteries, etc., are mainly used for these battery cells. If a battery cell experiences thermal runaway, in which the temperature rises suddenly and continues to generate heat due to an internal short circuit or overcharging, the heat from the battery cell experiencing thermal runaway may propagate to other adjacent battery cells, causing thermal runaway in the other battery cells. In addition, if a battery cell experiences thermal runaway, gas is generated inside the battery, causing the internal pressure to rise and causing deformation of the battery cell.

[0004] As a measure against the occurrence of thermal runaway as described above, for example, Patent Document 1 discloses a heat-transfer-suppressing sheet that has an excellent heat-transfer suppression effect and is capable of suppressing a decrease in the thickness of the insulating material even when the battery cell expands, thereby maintaining high insulating performance. The heat-transfer-suppressing sheet described in Patent Document 1 includes a first insulating material and a second insulating material, and the thermal conductivity of the first insulating material is lower than that of the second insulating material, and the compressive strength of the second insulating material is higher than that of the first insulating material. The second insulating material includes, for example, a frame body that covers the outer periphery of the first insulating material, a first plate-shaped member that covers one surface of the first insulating material, and a second plate-shaped member that covers the other surface.

[0005] Patent Document 2 proposes a heat insulating material that maintains its structure and suppresses deterioration of thermal conductivity against compressive stress. The heat insulating material described in Patent Document 2 includes a composite layer containing fibers and silica aerogel, and resin struts arranged in the thickness direction in the composite layer.

[0006] In the heat-transfer-suppressing sheet described in Patent Document 1, the frame and the first and second plate members that sandwich the first insulating material are made of the second insulating material having high compressive strength. Also, in the insulating material described in Patent Document 2, the compressive stress applied to the insulating material is dispersed by resin supports. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2020-187869 A [Patent Document 2] JP 2017-215014 A Summary of the Invention [Problem to be solved by the invention]

[0008] Incidentally, when the deformation of a battery cell due to thermal runaway is large, if a heat insulating material with high compressive strength or a resin support is arranged in the area where the battery cell and the heat insulating material are in contact, as in Patent Documents 1 and 2, a repulsive force is generated against the battery cell. When a battery cell undergoes thermal runaway, the central area of ​​the main surface is most susceptible to deformation, and if the spacing between the cells in the central area is fixed by a heat insulating material, the outermost battery cell of the multiple connected battery cells will be pressed against the battery case. As a result, the pressed battery cell or the case may be destroyed. Also, even when the battery cells in the assembled battery are subjected to a charge / discharge cycle (i.e., during "normal use"), slight deformation of the battery cell occurs.

[0009] In the heat transfer suppression sheet described in Patent Document 1 and the insulating material described in Patent Document 2, for example, when the internal pressure of the battery cell repeatedly rises and falls during charging and discharging, the battery cell is repeatedly pressed and released by the second insulating material or the resin support, causing a decrease in battery performance.

[0010] As described above, the center of the widest outer surface (main surface) of a battery cell is more likely to protrude due to expansion than the ends. Generally, terminals and exhaust valves are provided above the battery cell, and the exhaust valve side is likely to become hot in the event of an abnormality. Therefore, in the case of a frame that covers the outer periphery of the first insulating material, as in the heat transfer suppression sheet described in Patent Document 1, if the exhaust valve side of the battery cell becomes hot and the frame in the vicinity of it burns, it becomes difficult to maintain the desired thermal insulation.

[0011] The present invention has been made in consideration of the above-mentioned problems, and has an object to provide a heat transfer suppression member that can suppress destruction of the battery case and deterioration of battery performance due to deformation of the battery cells while ensuring spacing between the battery cells, and can maintain desired insulation properties even during abnormalities, and a battery pack that can suppress destruction of the battery case and deterioration of battery performance while suppressing heat transfer between the battery cells. [Means for solving the problem]

[0012] The above object of the present invention can be achieved by the following configuration [1] relating to a heat transfer suppressing member.

[0013] [1] A frame body that constitutes a part of the periphery in a plan view; A plate-shaped insulating material having a pair of main surfaces and end surfaces substantially perpendicular to the main surfaces, The frame has an outer end surface parallel to the end surface of the thermal insulation material, A heat transfer suppression member characterized in that at least a portion of the insulation material is arranged inside the frame body so that the end face of the insulation material exposed in the area of ​​the outer periphery where the frame body is not present is approximately flush in a plan view with at least a portion of the outer end face of the frame body, or protrudes from at least a portion of the outer end face of the frame body.

[0014] Further, preferred embodiments of the present invention relating to the heat transfer suppressing member relate to the following items [2] to

[17] .

[0015] [2] The frame body has a pair of frame members arranged approximately parallel to each other, The pair of frame members are connected to each other by one or more partition walls, and the inside of the frame body is divided into a plurality of regions by the partition walls, The heat transfer suppressing member according to [1], characterized in that it has a plurality of the heat insulating materials arranged in each of the plurality of regions.

[0016] [3] The heat transfer suppressing member described in [2], characterized in that the multiple insulating materials include a first insulating material and a second insulating material having mutually different properties.

[0017] [4] The heat transfer suppressing member described in [3], characterized in that the elastic modulus of the first insulating material is higher than the elastic modulus of the second insulating material.

[0018] [5] The heat transfer suppressing member described in [3] or [4], characterized in that the first insulating material is arranged in a centrally located region among the multiple regions.

[0019] [6] The heat transfer suppressing member according to any one of [2] to [5], further comprising a film that covers the main surfaces and the exposed end faces of the plurality of heat insulating materials.

[0020] [7] A heat transfer suppressing member described in any one of [2] to [5], characterized in that, in a cross-sectional view perpendicular to the planar view, the thickness of at least one of the plurality of insulating materials is thinner than the thickness of the frame body.

[0021] [8] A heat transfer suppressing member as described in [7], characterized in having a film covering the main surfaces and the exposed end faces of the multiple insulation materials.

[0022] [9] The heat transfer suppressing member described in [8], characterized in that a gap is provided between the main surface of the insulating material and the film.

[0023]

[10] A heat transfer suppressing member described in any one of [2] to [5] and [7], characterized in that an elastic material is laminated on at least one main surface of at least one of the plurality of insulating materials.

[0024]

[11] The heat transfer suppressing member according to

[10] , wherein the elastic material includes at least one selected from synthetic rubber, natural rubber, and thermoplastic elastomer.

[0025]

[12] A heat transfer suppressing member as described in

[10] or

[11] , characterized in having a film covering at least a portion of the outer main surface of the laminate of the insulating material and the elastic material.

[0026]

[13] The heat transfer suppressing member according to

[12] , characterized in that a gap is provided between the laminate and the film.

[0027]

[14] A heat transfer suppressing member described in any one of [2] to

[13] , characterized in that, in a plan view, the width of the partition wall in a direction perpendicular to the longitudinal direction is smaller than the width of the frame body in a direction perpendicular to the longitudinal direction.

[0028]

[15] The heat-transfer suppressing member according to any one of [2] to

[14] , wherein the partition wall is made primarily of an insulating material.

[0029]

[16] The heat-transfer suppressing member according to any one of [1] to

[15] , wherein the frame is made primarily of an insulating material.

[0030]

[17] The heat-transfer-suppressing member according to any one of [1] to

[16] , wherein the heat insulating material contains inorganic particles and organic fibers.

[0031] The above object of the present invention is achieved by the following configuration

[18] relating to a battery pack.

[0032]

[18] A battery pack comprising: a plurality of battery cells; and the heat transfer suppressing member according to any one of [1] to

[17] , the plurality of battery cells being connected in series or in parallel.

[0033] Furthermore, a preferred embodiment of the present invention relating to a battery pack relates to the following

[19] .

[0034]

[19] The plurality of battery cells have exhaust valves, the heat transfer suppressing member is interposed between the plurality of battery cells, The battery pack described in

[18] , characterized in that the heat transfer suppression member is arranged so that the exposed end face of the insulation material and the surface of the battery cell on which the exhaust valve is arranged are in the same direction.

[0035] The above object of the present invention is achieved by the following configuration

[20] relating to a battery pack.

[0036]

[20] A battery pack comprising a plurality of battery cells connected in series or parallel and the heat transfer suppressing member according to any one of [2] to

[17] , the heat transfer suppressing member is interposed between the plurality of battery cells, the heat transfer suppressing member is disposed so that the pair of frame members are substantially parallel to each other in a vertical direction. Effect of the Invention

[0037] Since the heat transfer suppression member of the present invention has a frame that constitutes part of the outer periphery, it is possible to ensure spacing between battery cells and suppress damage to the battery case and deterioration of battery performance due to deformation of the battery cells. Furthermore, since the insulating material is arranged so that the end face of the insulating material exposed in the area where the frame is not present is substantially flush with at least a part of the outer end face of the frame in a plan view or protrudes from at least a part of the outer end face of the frame, deterioration of insulating properties can be suppressed even if the frame is burned in the event of an abnormality.

[0038] Because the battery pack of the present invention has the above-mentioned heat transfer suppression member, it is possible to obtain a battery pack that can maintain excellent battery performance while suppressing the transfer of heat between each battery cell, and also suppressing damage to the battery case and deterioration of battery performance. [Brief description of the drawings]

[0039] [Figure 1A] FIG. 1A is a plan view showing a heat-transfer suppressing member according to a first embodiment of the present invention. [Figure 1B] FIG. 1B is a cross-sectional view taken along line II in FIG. 1A. [Diagram 2] FIG. 2 is a cross-sectional view that typically illustrates a battery pack having a heat-transfer-suppressing sheet according to the first embodiment of the present invention. [Diagram 3] FIG. 3 is a plan view showing Modification 1 of the heat transfer suppressing member according to the first embodiment of the present invention. [Figure 4] FIG. 4 is a plan view showing Modification 2 of the heat transfer suppressing member according to the first embodiment of the present invention. [Diagram 5] FIG. 5 is a cross-sectional view showing a heat-transfer suppressing member according to a second embodiment of the present invention. [Figure 6] FIG. 6 is a cross-sectional view showing a heat-transfer suppressing member according to a third embodiment of the present invention. [Figure 7] FIG. 7 is a cross-sectional view showing a heat-transfer suppressing member according to a fourth embodiment of the present invention. [Figure 8] FIG. 8 is a photograph substituting a drawing showing a first example of a structure of a heat insulating material used in a heat transfer suppressing member according to an embodiment of the present invention. [Figure 9] FIG. 9 is a photograph showing an enlarged view of a part of the heat insulating material shown in FIG. [Figure 10] FIG. 10 is a photograph showing a second example of the structure of a heat insulating material used in a heat transfer suppressing member according to an embodiment of the present invention. [Figure 11] FIG. 11 is a schematic diagram showing a third example of a structure of a heat insulating material used in a heat transfer suppressing member according to an embodiment of the present invention. [Figure 12] FIG. 12 is a schematic diagram showing an enlarged portion of FIG. [Figure 13] FIG. 13 is a photograph showing the heat insulating material shown in FIG. [Figure 14] FIG. 14 is a photograph showing a fourth example of a structure of a heat insulating material used in a heat-transfer suppressing member according to an embodiment of the present invention. [Figure 15] FIG. 15 is a photograph showing an enlarged view of the structure of the heat insulating material shown in FIG. [Figure 16] FIG. 16 is a photograph showing a cross section of the heat insulating material shown in FIG. [Figure 17] FIG. 17 is a schematic diagram showing a fifth example structure of a heat insulating material used in a heat transfer suppressing member according to an embodiment of the present invention. [Figure 18] FIG. 18 is an enlarged schematic view of part A of the heat insulating material shown in FIG. [Figure 19] FIG. 19 is a photograph showing a sixth example of a structure of a heat insulating material used in a heat-transfer suppressing member according to an embodiment of the present invention. [Figure 20] FIG. 20 is a photograph showing another area of ​​the heat insulating material shown in FIG. [Figure 21] FIG. 21 is a photograph showing a cross section of the heat insulating material shown in FIGS. [Figure 22] FIG. 22 is a photograph substituting a drawing showing a seventh example of a structure of a heat insulating material used in a heat-transfer suppressing member according to an embodiment of the present invention. [Figure 23] FIG. 23 is a photograph showing an enlarged view of a part of the heat insulating material shown in FIG. [Figure 24]FIG. 24 is a schematic diagram showing an example of a method for defining the length of a fiber bundle. [Diagram 25] FIG. 25 is a photograph showing another example of the structure of the heat insulating material shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0040] The inventors found that, although the heat transfer suppressing member interposed between the battery cells has a frame body, it is possible to suppress the application of unnecessary pressure to the battery cells, if the frame body is burned when an abnormality occurs, the thermal insulation of the area where the frame body was present is reduced. Therefore, the inventors found that, if the frame body is arranged only on a part of the outer periphery, and the end face of the thermal insulation material exposed in the area where the frame body is not present is arranged so as to be substantially flush with at least a part of the outer end face of the frame body in a plan view or to protrude from the frame body, it is possible to suppress the reduction in thermal insulation caused by the frame body being burned when an abnormality occurs in the battery cells. The present invention was made based on the above findings.

[0041] A heat transfer suppressing member according to an embodiment of the present invention, a manufacturing method thereof, and a battery pack will be described in detail below. Note that the present invention is not limited to the embodiment described below, and can be modified as desired without departing from the gist of the present invention. First, a heat transfer suppressing member according to an embodiment of the present invention will be described.

[0042] [Heat transfer suppression member] [First embodiment] FIG. 1A is a plan view showing a heat-transfer suppressing member according to a first embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along line II of FIG.

[0043] 1A and 1B, a heat transfer suppressing member 180 according to the first embodiment has a frame body 53 that constitutes part of the outer periphery in a plan view, and partition walls 58a, 58b provided inside the frame body 53. Specifically, the frame body 53 is made up of a pair of frame members 53b arranged opposite each other, and the partition walls 58a and 58b are formed to connect the pair of frame members 53a.

[0044] The inside of the frame 53 is divided into a plurality of regions (first region 57a, second region 57b, and third region 57c) by the partition walls 58a, 58b. In this embodiment, a plate-shaped first insulating material 10a is arranged in the first region 57a ​​and the second region 57b, and a plate-shaped second insulating material 10b is arranged in the third region 57c. In this embodiment, the first insulating material 10a is made of an insulating material having a smaller elastic modulus than the second insulating material 10b.

[0045] The first insulating material 10a and the second insulating material 10b each have a pair of main surfaces 10s perpendicular to the thickness direction, and an end surface 10e substantially perpendicular to the main surfaces. The frame 53 also has an outer end surface 53e parallel to the end surfaces 10e of the first insulating material 10a and the second insulating material 10b. The frame 53 constitutes part of the outer periphery of the heat transfer suppressing member 180 in a plan view, and a part of the end surfaces 10e of the first insulating material 10a and the second insulating material 10b is exposed without being covered by the frame 53. The first insulating material 10a and the second insulating material 10b are disposed inside the frame 53 so that the exposed end surfaces 10e of the first insulating material 10a and the second insulating material 10b and at least a part of the outer end surface 53e of the frame 53 are substantially flush with each other in a plan view. In addition, when a pair of main surfaces 10s and end surfaces 10e are "substantially perpendicular," it is acceptable for them to intersect within a range of 90°±5°, preferably within a range of 90°±3°, and more preferably within a range of 90°±1°. In addition, when the exposed end surfaces 10e of the first insulating material 10a and the second insulating material 10b are "substantially flush" with at least a portion of the outer end surface 53e of the frame body 53, the difference in height between them is acceptable to be up to 3 mm, preferably up to 2 mm, and more preferably up to 1 mm.

[0046] Furthermore, the heat transfer suppressing member 180 has a film 52 attached so as to entirely cover the first insulating material 10a, the second insulating material 10b, the frame 53, and the partition walls 58a, 58b. The exposed end faces 10e of the first insulating material 10a and the second insulating material 10b refer to the end faces of the regions not covered by the frame 53, regardless of the presence or absence of the film 52.

[0047] In this specification, "plan view" refers to the heat-transfer-suppressing member viewed from above when the pair of widest surfaces (principal surfaces 10s) of the sheet-like first and second insulating materials 10a and 10b are arranged facing in the vertical direction, and "cross-sectional view" refers to the cross-section of the heat-transfer-suppressing member viewed from a direction perpendicular to the plan view.

[0048] A specific use of the heat-transfer suppressing member 180 according to the first embodiment will be described below. FIG. 2 is a cross-sectional view that shows a schematic diagram of a battery pack having a heat-transfer suppressing sheet according to the first embodiment of the present invention. As shown in FIG. 2, the heat-transfer suppressing member 180 can be used by interposing the heat-transfer suppressing member 180 between a plurality of battery cells 20a, 20b, 20c. The battery pack 100 is configured by storing the plurality of battery cells 20a, 20b, 20c in a state in which they are connected in series or in parallel (the connected state is not shown). For example, lithium ion secondary batteries are preferably used as the battery cells 20a, 20b, 20c, but the present invention is not limited thereto and can be applied to other secondary batteries.

[0049] In this embodiment, when the heat transfer suppressing member 180 is interposed between the battery cells, a pair of frame members 53b are disposed facing each other so as to extend in the up-down direction (vertical direction) in the frame body 53. This divides the inside of the frame body 53 into a first region 57a, a second region 57b, and a third region 57c that extend in the horizontal direction. Therefore, the heat transfer suppressing member 180 shown in Fig. 2 represents a cross section taken along line II-II of the heat transfer suppressing member 180 shown in Fig. 1A.

[0050] In the battery pack 100 configured as described above, the frame 53 of the heat transfer suppressing member 180 is disposed between the battery cell 20a and the battery cell 20b, and between the battery cell 20b and the battery cell 20c. Therefore, by adjusting the thickness of the frame 53, a predetermined interval can be secured between the battery cells, and the desired thermal insulation performance can be maintained.

[0051] Furthermore, when the heat transfer suppressing member 180 is interposed between the multiple battery cells 20a, 20b, and 20c, the frame member 53b is not present at the upper and lower ends of the heat transfer suppressing member 180. In other words, the exposed end faces 10e of the first insulating material 10a and the second insulating material 10b are flush with the outer end face 53e of the frame member 53b. If the frame body 53 covered the entire outer periphery of the first insulating material 10a and the second insulating material 10b, part of the frame body 53 would be burned in the event of a significant rise in the temperature around the exhaust valve in an abnormality, and the insulating properties would be significantly reduced in the area where the frame body 53 was present.

[0052] In response to this, for example, an exhaust valve (not shown) is provided above the battery cells 20a, 20b, and 20c, and even if the temperature around the exhaust valve rises significantly in the event of an abnormality, the first insulating material 10a is present in the vicinity, so that the insulating properties can be sufficiently maintained.

[0053] In the present invention, the partition walls are not necessarily required, but as shown in the first embodiment, by arranging a plurality of insulating materials in a plurality of regions (first to third regions 57a, 57b, 57c), the volume of each insulating material can be reduced. As a result, the manufacturing of the insulating material becomes easier and the handling becomes easier. In this case, it is preferable to form the partition walls 58a, 58b so that all of the plurality of regions have substantially the same shape and size. With this configuration, even if some of the insulating materials are damaged in the event of an abnormality such as thermal runaway, it is possible to reuse the insulating materials that are not damaged in other heat transfer suppressing members, thereby reducing raw material costs and the burden on the environment. In addition, "substantially the same" as mentioned above means that differences in shape or size of each of the multiple regions are acceptable up to ±5% of the average value of all the multiple regions, preferably up to ±3%, and more preferably up to ±1%.

[0054] In this embodiment, the material constituting the partition wall and the width of the partition wall are not particularly limited. However, depending on the material of the partition wall, the insulation property may be inferior to that of the first insulation material 10a and the second insulation material 10b. In addition, when the partition wall is mainly made of, for example, a resin material, if the temperature around the heat transfer suppression member becomes extremely high in an abnormal situation, the resin material disappears and a hole penetrating from one main surface to the other main surface of the insulation material is formed, so that the insulation property is reduced. In this embodiment, the width Ws of the partition walls 58a and 58b in a direction perpendicular to the longitudinal direction in a plan view is formed smaller than the width Wf of the frame body 53 in a direction perpendicular to the longitudinal direction. Therefore, even if the partition walls 58a and 58b are burned, the area of ​​the hole in a plan view can be reduced, and the deterioration of the insulation property can be suppressed.

[0055] As described above, the battery cells 20a, 20b, and 20c are more likely to protrude due to expansion at the center than at the end of the widest outer surface (main surface). Furthermore, terminals and exhaust valves are generally provided above the battery cells, and in the event of an abnormality, the exhaust valve side is likely to become hot and deform. Therefore, in this embodiment, of the three divided regions (first region 57a, second region 57b, and third region 57c), the first insulating material 10a with a small elastic modulus is arranged in the first region 57a ​​located at the top and the second region 57b located at the center, and the second insulating material 10b with a larger elastic modulus than the first insulating material 10a is arranged in the third region 57c located at the bottom. That is, the first insulating material 10a arranged in the second region 57b located at the top and the center is softer and has a higher restoring force. Therefore, when the battery cells 20a, 20b, and 20c expand in the event of an abnormality, causing deformation of their central and upper parts, the first insulating material 10a, which has a small elastic modulus, can absorb the deformation of the battery cells. As a result, it is possible to prevent unnecessary pressure from being applied to the battery cells 20a, 20b, and 20c, and prevent deterioration of the battery performance.

[0056] In this embodiment, the multiple insulating materials arranged in the multiple regions divided by the partition walls have different elastic moduli, but insulating materials with different properties can be used as needed. For example, an insulating material with extremely excellent insulating properties can be arranged in the region with the highest temperature, and insulating materials that take cost and other factors into consideration can be arranged in the other regions. When insulating materials with different properties are arranged in each of the multiple regions, the types of insulating materials are not limited to two types, the first insulating material 10a and the second insulating material 10b, and three or more types of insulating materials each with different properties can be used.

[0057] Furthermore, in this embodiment, when the heat-transfer suppressing member 180 is incorporated into the battery pack 100, there are no frame members above or below the heat-transfer suppressing member 180, and the first insulating material 10a and the second insulating material 10b extend to the upper end or lower end, respectively. Therefore, even if the same insulating material is disposed in all regions, it is possible to ensure insulation in the exhaust valve region, which becomes particularly hot. For this reason, in the present invention, it is not necessarily necessary to dispose insulating materials with different properties in each of the multiple regions.

[0058] Furthermore, in this embodiment, the film 52 is attached so as to entirely cover the first insulating material 10a, the second insulating material 10b, the frame 53, and the partition walls 58a, 58b. Therefore, when the first insulating material 10a and the second insulating material 10b contain, for example, inorganic particles, it is possible to prevent the inorganic particles from falling off, i.e., preventing the inside of the battery case 30 from being contaminated by powder falling off.

[0059] The area where the film 52 is arranged is not particularly limited, and it is sufficient that the film 52 is formed to cover at least the main surface 10s and the exposed end surface 10e of the first heat insulating material 10a and the second heat insulating material 10b in order to prevent powder falling. Therefore, as shown in the first embodiment, the film 52 may be arranged so as to enclose the entirety, or the film 52 may be arranged so as to enclose each of the first heat insulating material 10a and the second heat insulating material 10b. The method of arranging the film is also not particularly limited, and the film 52 may be thermally fused to the frame body 53 and a part of the partition walls 58a and 58b, or the films may be joined together after wrapping the entirety with the film 52. In addition, the film 52 is not necessarily required in the present invention, and even if there is no film, the effect of the present invention that the heat insulating property can be maintained in the event of an abnormality can be obtained.

[0060] <Modification 1 of the First Embodiment> Fig. 3 is a plan view showing Modification 1 of the heat-transfer suppressing member according to the first embodiment of the present invention. In heat-transfer suppressing member 181 shown in Fig. 3, the same components as those in heat-transfer suppressing member 180 shown in Fig. 1A are denoted by the same reference numerals, and detailed descriptions thereof will be omitted or simplified.

[0061] In the first modification, when the heat transfer suppressing member 181 is interposed between the battery cells, the frame body 53 has a pair of frame members 53b extending in the up-down direction and frame members 53a extending inwardly in a substantially horizontal direction (left-right direction in the figure) from each end of the frame members 53b. Above the heat transfer suppressing member 181, one frame member 53a and the other frame member 53a are not connected. Similarly, below the heat transfer suppressing member 181, one frame member 53a and the other frame member 53a are not connected.

[0062] Partition walls 58a and 58b are formed to extend substantially horizontally and connect the pair of frame members 53b. As a result, the inside of the frame body 53 is divided into three regions, a first region 57a, a second region 57b, and a third region 57c, in that order from the top. The first insulating material 10a arranged in the first region 57a ​​has an exposed end face 10e in a region where the frame member 53a is not present. The second insulating material 10b arranged in the third region 57c also has an exposed end face 10e in a region where the frame member 53a is not present.

[0063] The heat transfer suppressing member 181 configured as above can also provide various effects similar to those of the first embodiment. In particular, when the heat transfer suppressing member 181 is used in place of the heat transfer suppressing member 180 of the battery pack 100, the frame body 53 is not present at the upper end and the lower end of the heat transfer suppressing member 181. That is, the exposed end faces 10e of the first insulating material 10a and the second insulating material 10b are flush with the outer end faces 53e of the frame members 53a and 53b. Therefore, even if the temperature around the exhaust valve rises significantly in an abnormality, the first insulating material 10a is present around the exhaust valve, so that the thermal insulation can be sufficiently maintained.

[0064] The exhaust valve of the battery cell is not limited to being located at the top, and may be located at the bottom, but in this embodiment, the frame 53 does not exist even in the bottom region, and the end face 10e of the second insulating material 10b is exposed. Therefore, by setting the positions of the first insulating material 10a and the second insulating material 10b in consideration of the positions of the exhaust valves, etc., it is possible to maintain thermal insulation even during abnormal conditions.

[0065] <Modification 2 of the First Embodiment> Fig. 4 is a plan view showing Modification 2 of the heat-transfer suppressing member according to the first embodiment of the present invention. In a heat-transfer suppressing member 182 shown in Fig. 4, the same components as those in the heat-transfer suppressing member 180 shown in Fig. 1A are denoted by the same reference numerals, and detailed descriptions thereof will be omitted or simplified.

[0066] In the second modification, when the heat transfer suppressing member 182 is interposed between the battery cells, the frame body 53 has a pair of frame members 53b facing each other in the left-right direction, and one frame member 53a connecting the lower ends of these frame members 53b. In this embodiment, no partition wall is formed, and one sheet of thermal insulation material 10 is disposed in the area inside the frame members 53a and 53b. Therefore, the upper end face 10e of the thermal insulation material 10 is not covered by the frame body 53 and is exposed.

[0067] The heat transfer suppressing member 182 configured as described above can also provide the same effects as the first embodiment when used in place of the heat transfer suppressing member 180 of the battery pack 100. Moreover, because the thermal insulation material 10 has an exposed end surface 10e on only one side of the heat transfer suppressing member 182, the orientation of the heat transfer suppressing member 182 can be easily set in consideration of the positions of the exhaust valves, etc. of the battery cells 20a, 20b, 20c.

[0068] In heat transfer suppressing members 180, 181 having partition walls, it is preferable that the first insulating material 10a having a low elastic modulus is disposed in at least the central region among the multiple regions divided by the partition walls. Furthermore, when the heat transfer suppressing members 180, 181 are disposed between the battery cells 20a, 20b, 20c, it is also preferable that the first insulating material 10a is disposed near the exhaust valves of the battery cells 20a, 20b, 20c.

[0069] The partition wall has the function of dividing the inside of the frame body into a plurality of regions and the function of connecting the opposing frame members. However, if the partition wall is located near the center of the heat transfer suppression member in a plan view, the partition wall acts as a resistance and repeatedly presses and releases the battery cell during charging and discharging of the battery cell, causing a decrease in battery performance. Therefore, it is preferable that the partition wall is not located in the center or a region close to the center of the inside of the frame body. With reference to FIG. 3, when a pair of frame members 53b facing each other in the left-right direction are connected by a partition wall, it is preferable to form the partition wall so as to divide the inner region of the frame body 53 equally, taking into consideration the possibility of reusing the insulating material. At this time, in order to prevent the partition wall from being located in the center or a region close to the center of the inside of the frame body, it is preferable to connect the pair of opposing frame members 53b by an even number of partition walls.

[0070] In addition, in both variants 1 and 2, a film may be placed to directly or indirectly cover the surface of the first insulating material 10a and the second insulating material 10b, or the insulating material 10, and there is no particular limitation on the method of placing the film.

[0071] [Second embodiment] Fig. 5 is a cross-sectional view showing a heat-transfer suppressing member according to a second embodiment of the present invention. In a heat-transfer suppressing member 190 shown in Fig. 5, the same components as those in the first embodiment shown in Figs. 1A and 1B are given the same reference numerals, and detailed description thereof will be omitted or simplified. In the second embodiment, the structure of the frame 53 and the configurations of the first and second insulating materials 10a and 10b are the same as those in the first embodiment, so the configuration of the heat-transfer suppressing member 190 will be described below using the plan view shown in Fig. 1A and Fig. 5, which is a cross-sectional view taken along line II-II in Fig. 1A.

[0072] In the heat transfer suppressing member 190 according to the second embodiment, the second insulating material 10b, the first insulating material 10a, and the second insulating material 10b, each of which is thinner than the thickness of the frame body 53, are disposed in the first region 57a, the second region 57b, and the third region 57c, respectively. The first insulating material 10a is made of an insulating material having a smaller elastic modulus than the second insulating material 10b. Furthermore, a film 52 is disposed so as to entirely cover the frame body 53, the partition walls 58a, 58b, the first insulating material 10a, and the second insulating material 10b.

[0073] A specific example of application of the heat transfer suppressing member 190 configured as described above to a battery pack will be described below. Here, the case where the heat transfer suppressing member 190 shown in Fig. 5 is applied instead of the heat transfer suppressing member 180 of the battery pack 100 shown in Fig. 2 will be described.

[0074] The heat transfer suppressing member 190 configured as above can also provide the same effects as those of the first embodiment. In this embodiment, the first insulating material 10a and the second insulating material 10b, which are thinner than the frame body 53, are disposed inside the frame body 53. Therefore, although the film 52 exists between the first insulating material 10a and the second insulating material 10b and the battery cells 20a, 20b, and 20c, a gap 54 is formed. Therefore, when the battery cells 20a, 20b, and 20c expand, the gap 54 serves as an escape route for the expansion. Therefore, it is possible to further suppress the application of unnecessary pressure to the battery cells 20a, 20b, and 20c, and to suppress a decrease in battery performance.

[0075] In addition, while the first insulating material 10a and the second insulating material 10b have a predetermined insulating property, in this embodiment, there is a gap 54 between the first insulating material 10a and the second insulating material 10b and the film 52, and since air is present in this gap 54, an even better insulating effect can be obtained by the air.

[0076] In this embodiment, it is not necessary for both the first insulating material 10a and the second insulating material 10b to be thinner than the frame body 53, but it is sufficient that at least one of the insulating materials is formed to be thinner than the frame body 53. For example, by making only the first insulating material 10a thin, a void portion 54 is formed in the area where the battery cell expands, which provides the effect of reducing the repulsive force on the battery cell, and the void portion 54 also provides the effect of improving the insulation. In this case, the elastic modulus, insulation performance, etc. of the first insulating material 10a and the second insulating material 10b may be the same or different from each other.

[0077] In the present invention, there is no particular limitation on the configuration of the film 52. For example, the film 52 may be disposed so as to cover only the first insulating material 10a and the second insulating material 10b, and a gap may be formed between the film 52 and the battery cells 20a, 20b, and 20c.

[0078] In addition, in the present invention, the film 52 is not necessarily required. Even if the heat transfer suppressing member does not have the film 52, the first heat insulating material 10a and the second heat insulating material 10b are formed to be thinner than the frame body 53, so that a step is generated between the frame body 53 and the first heat insulating material 10a and the second heat insulating material 10b in a cross-sectional view. Specifically, the main surfaces of the first heat insulating material 10a and the second heat insulating material 10b are recessed more than the frame body 53. Therefore, when the heat transfer suppressing member 190 is interposed between the battery cells 20a, 20b, and 20c, the presence of the frame body 53 can ensure the gap portion 54. As a result, it is possible to further suppress the application of unnecessary pressure to the battery cells when the battery cells expand.

[0079] [Third embodiment] Fig. 6 is a cross-sectional view showing a heat-transfer suppressing member according to a third embodiment of the present invention. In the heat-transfer suppressing member 200 shown in Fig. 6, the same components as those shown in Fig. 1B are given the same reference numerals, and detailed description thereof will be omitted or simplified. In the third embodiment, the structure of the frame 53 and the configurations of the first and second insulating materials 10a and 10b are the same as those in the first embodiment, so the configuration of the heat-transfer suppressing member 200 will be described below using the plan view shown in Fig. 1A and Fig. 6, which is a cross-sectional view taken along line II-II in Fig. 1A.

[0080] 6, in a heat transfer suppressing member 200 according to the third embodiment, an elastic material 51 is laminated on the main surfaces of the first insulating material 10a and the second insulating material 10b. That is, the first insulating material 10a and the second insulating material 10b are each sandwiched between a pair of elastic materials 51 to form a laminate 111. The thickness of the laminate 111 is configured to be substantially the same as the thickness of the frame 53, and the film 52 is disposed so as to cover the frame 53, the partition walls 58a, 58b, and the entire laminate 111. Therefore, most of the outer main surfaces 111s of the laminate 111 and the film 52 are in contact with each other, and no voids are formed. In addition, when the thickness of the laminate 111 and the thickness of the frame body 53 are "approximately the same," this means that the difference between the two thicknesses is acceptable up to ±5% of the average value of the two, preferably up to ±3%, and more preferably up to ±1%.

[0081] A specific example of application of the heat-transfer-reducing member 200 configured as described above to a battery pack will be described below. Here, the case where the heat-transfer-reducing member 200 shown in Fig. 6 is applied instead of the heat-transfer-reducing member 180 of the battery pack 100 shown in Fig. 2 will be described.

[0082] In this embodiment, the same effect as in the first embodiment can be obtained. In addition, since the elastic material 51 is laminated on both the main surfaces of the first insulating material 10a and the second insulating material 10b, and the film 52 is present on the outer main surface 111s of the laminate 111 consisting of the insulating material and the elastic material, powder falling can be further suppressed when the first insulating material 10a and the second insulating material 10b contain inorganic particles or the like. In particular, even if the film 52 is broken in the event of an abnormality, contamination due to powder falling can be prevented if the main surfaces of the first insulating material 10a and the second insulating material 10b are covered with the elastic material 51.

[0083] Furthermore, in the third embodiment, an elastic material 51 is disposed instead of the void portion 54 shown in the second embodiment. The elastic material 51 has elasticity, and when the heat transfer suppressing member 200 is pressed by the expansion of the battery cells 20a, 20b, and 20c, the elastic material 51 deforms by an appropriate amount, thereby suppressing the repulsive force on the battery cells. In other words, when the battery cells 20a, 20b, and 20c are deformed, the elastic material 51 flexibly deforms in response to the deformation of the battery cells 20a, 20b, and 20c while suppressing the deformation of the battery cells 20a, 20b, and 20c. Therefore, in the heat transfer suppressing member 200 according to the third embodiment, as in the second embodiment in which the void portion 54 is formed, the deterioration of battery performance caused by repeated pressing and relaxing of the battery cells 20a, 20b, and 20c can be suppressed.

[0084] In the third embodiment, the first insulating material 10a and the second insulating material 10b have different properties. For example, when the elastic modulus of the first insulating material 10a is smaller than that of the second insulating material 10b, the deformation of the battery cell can be absorbed most in the central and upper regions, and the repulsive force can be further suppressed. Furthermore, the first insulating material 10a and the second insulating material 10b may be the same, or may have different insulating properties as necessary.

[0085] In the third embodiment, the elastic material 51 is laminated on both the main surfaces of the first insulating material 10a and the second insulating material 10b, but the present invention is not limited thereto. For example, the elastic material 51 may be laminated only on both main surfaces of the first insulating material 10a. Also, the elastic material 51 may be sandwiched between a pair of the first insulating material 10a and a pair of the second insulating material 10b. Furthermore, the elastic material 51 may be laminated only on one main surface of the first insulating material 10a and the second insulating material 10b. In this case, the thickness of the two-layered laminate 111 of the first insulating material 10a, the second insulating material 10b, and the elastic material 51 can be made thinner than that of a three-layered laminate. Specifically, the two-layered laminate 111 is preferably thinner than the thickness of the frame 53, and the position of the laminate 111 in the thickness direction is preferably adjusted so that a gap is formed between the other main surface of the insulating material on which the elastic material 51 is not laminated and the battery cell.

[0086] As in the first and second embodiments, in the third embodiment, the film 52 may or may not be arranged. When using a two-layer laminate 111 of the first and second insulating materials 10a and 10b and the elastic material 51, it is preferable that the film 52 is arranged so as to cover at least the main surfaces of the first and second insulating materials 10a and 10b on which the elastic material 51 is not laminated. This results in the main surfaces of both the first and second insulating materials 10a and 10b being covered with the elastic material 51 or the film 52, and the effect of suppressing powder falling can be obtained. In addition, the film 52 may be arranged so as to enclose only the first and second insulating materials 10a and 10b.

[0087] [Fourth embodiment] Fig. 7 is a cross-sectional view showing a heat-transfer suppressing member according to a fourth embodiment of the present invention. In a heat-transfer suppressing member 210 shown in Fig. 7, the same components as those shown in Fig. 6 are given the same reference numerals, and detailed description thereof will be omitted or simplified. In the fourth embodiment, the structure of the frame 53 and the configurations of the first and second insulating materials 10a and 10b are the same as those in the first embodiment, so the configuration of the heat-transfer suppressing member 210 will be described below using the plan view shown in Fig. 1A and Fig. 7, which is a cross-sectional view taken along line II-II in Fig. 1A.

[0088] 7, in the fourth embodiment, a laminate 111 of a first insulating material 10a, a second insulating material 10b, and an elastic material 51 laminated on the main surfaces of both of them is formed to be thinner than a frame body 53. A film 52 is disposed so as to cover all of the frame body 53, the partition walls 58a, 58b, and the laminate 111 with a gap 54 interposed therebetween.

[0089] When the heat transfer suppressing member 210 configured as described above is applied instead of the heat transfer suppressing member 180 of the battery pack 100, the same effect as that of the third embodiment can be obtained. In addition, since the laminate 111 has the voids 54 on both outer main surfaces 111s, the heat insulation can be improved compared to the third embodiment. It is preferable that the voids 54 are present between at least one of the outer main surfaces 111s of the laminate 111 and the film 52, and it is more preferable that the voids 54 are present between both outer main surfaces 111s and the film 52. In the fourth embodiment, the laminate 111 may be configured by laminating an elastic material 51 on at least one main surface of at least one of the first and second insulating materials 10a and 10b. In addition, the presence or absence of the film 52 and the arrangement thereof are the same as those of the first and second embodiments.

[0090] In the first to fourth embodiments described above, the end face of the insulating material exposed in the region of the outer periphery of the heat transfer suppressing member where the frame body 53 is not present is configured to be substantially flush with at least a portion of the outer end face of the frame body in a plan view, but the present invention is not limited to this. At least a portion of the exposed end face of the insulating material may be disposed inside the frame body 53 so as to protrude from at least a portion of the outer end face of the frame body. In this way, even if the insulating material is configured to protrude from the frame body, it is possible to suppress a decrease in insulating properties due to the frame body being burned when an abnormality occurs in the battery cell.

[0091] The materials constituting the heat transfer suppressing member according to this embodiment will be described below.

[0092] <Frame> The frame has the function of ensuring a gap between adjacent battery cells under normal conditions. Therefore, the frame is preferably made mainly of an insulating material, and more preferably made of a material having appropriate hardness and heat insulation. The main material constituting the frame is preferably at least one insulating material selected from, for example, a resin material, an oxide ceramic, a non-oxide ceramic, a silicate mineral such as mica, and a composite material of resin and ceramic. Of these, it is more preferable to use a resin material as the main material, since it has excellent workability in addition to properties such as hardness and heat insulation. The shape of the frame is not particularly limited as long as it provides the above-mentioned effects, and may be made of, for example, an inorganic fiber mat material.

[0093] <Partition wall> When the heat transfer suppressing member according to the present embodiment has a partition wall, the partition wall divides the inside of the frame body into a plurality of regions and has the effect of holding a plurality of heat insulating materials together with the frame body. The partition wall also has the effect of connecting a plurality of frame members. Therefore, like the frame body, the partition wall is preferably made mainly of an insulating material, and more preferably made of a material having appropriate hardness and heat insulation. That is, the partition wall is preferably made mainly of at least one insulating material selected from a resin material, an oxide ceramic, a non-oxide ceramic, a silicate mineral such as mica, and a composite material of resin and ceramic. In addition, from the viewpoint of hardness, heat insulation, processability, and the like, it is more preferable that the partition wall is made mainly of a resin material. The frame body and the partition wall may be integrally molded or may be formed by combining a plurality of members. These materials may also be formed of the same material or different materials. The partition wall may have any shape as long as it can achieve the above-mentioned functions and effects, and may be made of, for example, an inorganic fiber mat material.

[0094] <Thermal insulation> The heat insulating material is not particularly limited as long as it can obtain the desired heat insulating effect. Thermal conductivity can be mentioned as an index showing the heat insulating effect. In the present embodiment, the heat conductivity of the heat insulating material is preferably less than 1 (W / m·K), more preferably less than 0.5 (W / m·K), and more preferably less than 0.2 (W / m·K). Furthermore, the heat conductivity of the heat insulating material is more preferably less than 0.1 (W / m·K), more preferably less than 0.05 (W / m·K), and particularly preferably less than 0.02 (W / m·K). As a heat insulating material capable of obtaining a desired heat insulating effect, for example, a heat insulating material containing silicon-based rubber and aerogel, a heat insulating material containing fiber and aerogel, a heat insulating material containing inorganic particles and organic fibers, etc. can be used. The heat conductivity of the heat insulating material can be measured in accordance with the "Test method for heat conductivity of refractory materials" described in JIS R 2251.

[0095] (Insulation size) When laminating an insulating material and an elastic material, the size of the main surface of the insulating material and the size of the main surface perpendicular to the thickness direction of the elastic material may be approximately the same, or the elastic material may be formed smaller than the insulating material. In addition, the above term "substantially the same" means that the difference in size of the main surfaces of both can be up to ±5% of the average value of both, preferably up to ±3%, and more preferably up to ±1%.

[0096] (Thermal insulation material containing silicon rubber and aerogel) The heat insulating material containing silicon rubber and aerogel is made of silicon rubber as a framework and SiO 2 Examples of the silicone rubber include those impregnated with silicone and rubber with a heat resistance of 170°C or higher. Aerogel has many cavities, so it can provide excellent heat insulation.

[0097] (Insulation material containing fiber and aerogel) As a thermal insulation material containing fiber and aerogel, SiO 2Examples of the fibers include those impregnated with alumina. As the fibers, polyacrylonitrile (PAN) fibers, glass fibers, ceramic fibers, and the like can be used. Since aerogel has many cavities, it is possible to obtain excellent heat insulation. A heat insulating material containing fibers and aerogel can be used as the heat insulating material 10, the first heat insulating material 10a, and the second heat insulating material 10b of the heat transfer suppressing member according to the embodiment of the present invention. By adjusting the content of the fibers and aerogel, it is possible to change the elastic modulus, heat insulating performance, and the like of the heat insulating material.

[0098] (Thermal insulation material containing inorganic particles and organic fibers) When a thermal insulation material containing inorganic particles and organic fibers, particularly a thermal insulation material having the structure shown below, is used, it is possible to obtain even better thermal insulation properties than a thermal insulation material containing the above-mentioned fibers and aerogel. Examples of such specific thermal insulation materials are described in detail below.

[0099] <Thermal insulation (Structure example 1)> FIG. 8 is a drawing substitute photograph showing a structural example 1 of a heat insulating material used in a heat transfer suppressing member according to an embodiment of the present invention, and FIG. 9 is a drawing substitute photograph showing an enlarged portion of the heat insulating material shown in FIG. 8. The heat insulating materials of structural examples 1 to 7 shown below can be used as the heat insulating material 10, the first heat insulating material 10a, and the second heat insulating material 10b of the above embodiment. The elastic modulus, heat insulating performance, and the like can also be changed by adjusting the content of inorganic particles and organic fibers. In addition, when the heat transfer suppressing member has the first heat insulating material 10a and the second heat insulating material 10b, these may be made of different materials.

[0100] As shown in Figures 8 and 9, the heat insulating material has inorganic particles 4 and organic fibers 1. The heat insulating material also has a plurality of three-dimensionally connected pores 7 between the inorganic particles 4 and the organic fibers 1. The organic fibers 1 have welded parts 5 covering at least a part of their surfaces, and at least a part of the inorganic particles 4 are welded to the surfaces of the organic fibers 1 by the welded parts 5. As a result, the surfaces of the organic fibers 1 are covered with the inorganic particles 4.

[0101] In the insulating material configured in this manner, since it has a plurality of three-dimensionally connected pores 7, it is possible to obtain the effect of air insulation and further improve the insulating performance. In addition, since the insulating material contains organic fibers 1 having high flexibility, it is possible to increase the flexibility of the insulating material, and the organic fibers 1 are easily entangled with each other, which has the effect of improving the strength of the insulating material. Therefore, it is possible to suppress the destruction of the heat transfer suppressing member having such an insulating material. Furthermore, since the existence of the pores 7 in the insulating material improves the cushioning property of the entire sheet, when the battery cells 20a, 20b, and 20c expand during charging and discharging, the expansion of the battery cells is absorbed by the insulating material, and the deterioration of the performance of the battery cells can be further suppressed.

[0102] Furthermore, in this embodiment, it is preferable that at least some of the holes 7 communicate with the surface of the insulating material and open outward. With holes 7 configured in this manner, even if the insulating material becomes hot and the organic fibers 1 and the like are decomposed when adjacent battery cells 20a, 20b, 20c experience thermal runaway, the decomposition gas does not remain inside the sheet but is released to the outside through holes 7. Therefore, from this point of view, the effect of preventing destruction of the sheet can be obtained.

[0103] Furthermore, when the welded portion 5 on the outer peripheral surface of the organic fiber 1 fixes the inorganic particles 4 to the organic fiber 1, it is possible to obtain the effect of suppressing the falling off (powdering) of the inorganic particles 4. Therefore, even if, for example, part of the battery cells 20a, 20b, 20c expands and compressive stress or impact is applied to the heat transfer suppressing member, it is possible to further enhance the effect of maintaining the shape of the insulating material, and to prevent a decrease in the insulating effect due to compressive deformation of the insulating material.

[0104] In this specification, the welded portion 5 refers to a portion where the surface of the organic fiber 1 melts and then solidifies again, and is formed in the manufacturing process of the insulation material described below. In this embodiment, the inorganic particles 4 are welded to the surface of the organic fiber 1 by the welded portion 5, so that the apparent fiber diameter of the organic fiber 1 becomes large, which supports the shape of the insulation material and provides high strength.

[0105] The welded portion 5 does not need to completely cover the outer periphery of the organic fiber 1, and there may be some areas where the welded portion 5 is not present. In the heat insulating material, binder fibers having a core-sheath structure, which will be described later, can be used as the material for the organic fiber 1, but if the sheath portion peels off during the manufacturing process, the organic fiber 1, which is the core portion, may be partially exposed. Even in such a case, the effect of holding the inorganic particles 4 can be sufficiently obtained.

[0106] Furthermore, the heat insulating material preferably contains inorganic fibers. The effect obtained by containing inorganic fibers will be described in the following structural example 2 of the heat insulating material.

[0107] <Thermal insulation (Structure example 2)> Fig. 10 is a photograph showing a second structural example of a heat insulating material used in a heat transfer suppressing member according to an embodiment of the present invention. In the second structural example shown in Fig. 10, the same components as those in the first structural example shown in Fig. 8 and Fig. 9 are designated by the same reference numerals, and detailed descriptions thereof will be omitted.

[0108] As shown in Fig. 10, the heat insulating material 40 has inorganic fibers 15. The heat insulating material 40 has a fiber layer 11 formed on at least a part of a first surface 40a and a second surface (not shown) perpendicular to the thickness direction of the heat insulating material 40. The fiber layer 11 is formed by welding at least a part of a plurality of organic fibers 1 to each other at welding parts, and is formed in a layer on the surface (first surface and second surface) of the heat insulating material 40. That is, the fiber layer 11 is a layer formed by gathering 10 or more organic fibers 1 on the surface of the heat insulating material 40, and extends, for example, in stripes, in a direction approximately parallel to the surface.

[0109] Furthermore, a composite layer (not shown) containing a mixture of part of the fiber layer 11 and part of the inorganic particles 4 is formed between the fiber layer 11 and the base layer 13 containing the inorganic particles 4 and the organic fibers 1. Specifically, the composite layer is a region containing a plurality of organic fibers 1 at least partially welded to one another by welded parts, and inorganic particles 4 welded to the organic fibers 1 by welded parts.

[0110] In the heat insulating material 40 shown in Fig. 10, the inorganic fibers 15 are contained in the base layer 13 containing the inorganic particles 4 and the organic fibers 1, but may also be contained in the fiber layer 11. In Fig. 10, the inorganic fibers 15 in the fiber layer 11 cannot be distinguished, so they are not shown.

[0111] Furthermore, the thermal insulation material 40 has a fiber bundle 6 formed by at least a portion of a plurality of organic fibers 1 being welded together by a welded portion 5. The "fiber bundle 6" is formed by entangling 10 or more organic fibers 1 with one another and welding the organic fibers 1 to one another at some portions, and is arranged in an arbitrary direction in the thermal insulation material 40.

[0112] The heat insulating material 40 configured in this manner contains inorganic fibers 15 that are difficult to decompose even at high temperatures. Therefore, for example, if the battery cell 20a experiences thermal runaway and the heat transfer suppressing member disposed adjacent to the battery cell 20a is exposed to high temperatures, even if the organic fibers 1 in the heat insulating material 40 decompose, the inorganic fibers 15 remain, so that the shape of the heat insulating material 40 can be reliably maintained. In addition, the flexible organic fibers 1 tend to become entangled with the relatively hard inorganic fibers 15, and the inorganic fibers 15 and the organic fibers 1 form a three-dimensional skeleton, so that the strength of the heat insulating material 40 can be further improved.

[0113] Furthermore, when the heat insulating material 40 has a fiber layer 11 on its surface and a fiber bundle 6 inside, it can obtain a higher strength than when the organic fiber 1 is dispersed and arranged. The fiber layer 11 is not simply arranged on the base layer 13, but has a composite layer between the fiber layer 11 and the base layer 13 in which a part of the fiber layer 11 and a part of the inorganic particles 4 are mixed, so that the fiber layer 11 is securely bound to the surface of the heat insulating material 40. Therefore, only the fiber layer 11 does not fall off, and a heat insulating material 40 having high strength can be obtained. In addition, when an elastic material 51 is laminated on the heat insulating material, for example, as shown in the third and fourth embodiments, the pressure applied to the base layer 13 can be further reduced.

[0114] Furthermore, when a fiber layer 11 is formed on the surface of the insulation material 40, this fiber layer 11 can absorb impacts applied to the insulation material 40, so that even if the elastic material 51 is not laminated, the fiber layer 11 can have the effect of preventing the inorganic particles contained in the insulation material 40 from falling off.

[0115] <Thermal insulation (Structure example 3)> Fig. 11 is a schematic diagram showing a third structural example of a heat insulating material used in a heat-transfer suppressing member according to an embodiment of the present invention, and Fig. 12 is a schematic diagram showing an enlarged portion of Fig. 11. Also, Fig. 13 is a photograph showing the heat insulating material shown in Fig. 11. In Structural Example 3 shown in Figs. 11 to 13, the same components as those in Structural Example 1 shown in Figs. 8 and 9 are given the same reference numerals, and detailed descriptions thereof will be omitted.

[0116] As shown in FIG. 11 to FIG. 13, the heat insulating material 60 according to this embodiment has inorganic particles 4, organic fibers 1 made of a first organic material, and a welded portion 5 covering the outer circumferential surface of the organic fibers 1. As described above, the welded portion 5 includes a second organic material 17 having a melting point lower than that of the first organic material, and inorganic particles 4. In this embodiment, a binder fiber 3 having a core-sheath structure with a core and a sheath covering the outer circumferential surface of the core is used as the organic fiber, and the organic fiber 1 corresponds to the core. The welded portion 5 is formed by melting the sheath of the binder fiber 3 having a core-sheath structure by heating and then cooling it. Furthermore, as shown in FIG. 13, a fiber portion 16 is formed by the organic fiber 1 and the welded portion 5 including the inorganic particles 4, and a matrix portion 18 including the inorganic particles is formed between the multiple fiber portions 16. When the melted sheath portion is cooled, the adjacent organic fibers 1 are fused to each other at the contact portion 31 to form a three-dimensional skeleton.

[0117] In the insulating material 60 configured in this manner, the organic fibers 1 and the welded parts 5 act as a skeleton, so that excellent strength and shape retention can be obtained. Furthermore, on both the surface side and the center side of the insulating material 60, the welded parts 5 covering the outer periphery of the organic fibers fix the inorganic particles 4 to the organic fibers 1, so that powder falling off can be suppressed. Furthermore, as shown in the first to fourth embodiments, if an insulating material with a low elastic modulus, for example, is arranged in an area of ​​a battery cell that is significantly deformed, excellent insulating performance can be maintained even if a heat transfer suppressing member is arranged between multiple battery cells and the battery cells expand, causing a compressive stress or impact on the heat transfer suppressing member.

[0118] Although the mechanism by which the insulating material 60 can prevent the inorganic particles 4 from falling off (powdering) is not clear, one of the reasons is thought to be that the organic fibers 1 and the welded parts 5 form a three-dimensional, strong skeleton, which maintains the shape of the insulating material 60 and thus prevents deformation or compression of the insulating material 60. Furthermore, as shown in the third and fourth embodiments, when an elastic material 51 is laminated on at least one surface of the insulating material 60, the pressure on the insulating material 60 is reduced, and the inorganic particles 4 can be further prevented from falling off.

[0119] Furthermore, it is believed that the inorganic particles 4 are retained because the fiber portion 16 exposed on the surface of the insulation material 60 can absorb impacts applied to the insulation material 60, regardless of whether or not there is a film covering the surface of the insulation material 60 or an elastic material 51 laminated to the insulation material 60.

[0120] 13, in the insulating material 60, the welded portion 5 does not need to completely cover the outer peripheral surface of the organic fiber 1, and the organic fiber 1 may be partially exposed. Since the insulating material 60 uses binder fiber 3 with a core-sheath structure, the sheath portion may peel off during the manufacturing process of the insulating material 60, but even if the organic fiber 1 is partially exposed, the effect of the present invention can be sufficiently obtained.

[0121] <Thermal insulation (Structure example 4)> Fig. 14 is a photograph substituting a drawing showing a fourth structural example of a heat insulating material used in a heat-transfer suppressing member according to an embodiment of the present invention, and Fig. 15 is a photograph substituting a drawing showing an enlarged view of the structure of the heat insulating material shown in Fig. 14. Fig. 16 is a photograph substituting a drawing showing a cross section of the heat insulating material shown in Fig. 14. In Structural example 4 shown in Figs. 14 to 16, the same components as in Structural example 1 shown in Figs. 8 and 9 are given the same reference numerals and detailed description thereof will be omitted.

[0122] 14 and 15, the heat insulating material 70 has a matrix 14 containing inorganic particles 4, and organic fibers 1 oriented three-dimensionally in the matrix 14. The organic fibers 1 have welded parts 5 covering at least a part of their surfaces, and the organic fibers 1 are welded to each other by the welded parts 5. Similarly, the inorganic particles 4 are welded to the surfaces of the organic fibers 1, so that the surfaces of the organic fibers 1 are covered with the inorganic particles 4.

[0123] As shown in the cross-sectional view of Fig. 16, a plurality of voids 7 are formed in the matrix 14 of the thermal insulation material 70. Furthermore, at least some of the organic fibers 1 in the matrix 14 are welded to each other by welded parts 5 not shown in Fig. 16 to form fiber bundles 6, and voids 8 are formed between the organic fibers 1 constituting the fiber bundles 6.

[0124] Furthermore, a fiber layer 11 is formed on at least a part of the first surface 70a and the second surface (not shown) perpendicular to the thickness direction of the heat insulating material 70. The fiber layer 11 is formed in a layer on the surface (first surface and second surface) of the heat insulating material 70 by welding at least a part of the organic fibers 1 to each other by the welding parts 5. In addition, a composite layer 12 is formed between the fiber layer 11 and the base layer 13 containing the matrix 14 and the organic fibers 1. The composite layer 12 is a layer in which a part of the fiber layer 11 and a part of the matrix 14 are mixed. Specifically, the composite layer 12 is a region including a plurality of organic fibers 1 at least a part of which are welded to each other by the welding parts 5, and inorganic particles 4 welded to the organic fibers 1 by the welding parts 5.

[0125] The fiber bundles 6 are formed by entangling 10 or more organic fibers 1 with one another and by welding the organic fibers 1 to one another in some places, and are arranged in an arbitrary direction in the matrix 14 of the thermal insulation material 70. On the other hand, the fiber layer 11 is a layer formed by assembling 10 or more organic fibers 1 on the surface of the thermal insulation material 70, and extends, for example, in stripes in a direction substantially parallel to the surface.

[0126] In the insulating material 70 configured in this manner, the organic fibers 1 are oriented three-dimensionally in the matrix 14, and the organic fibers 1 have welded parts 5 that cover at least a portion of their surfaces. The "welded parts 5" refer to parts where the surfaces of the organic fibers 1 melt and then solidify again, and are formed during the manufacturing process of the insulating material 70. In the insulating material 70, the three-dimensionally oriented organic fibers 1 are welded to each other by the welded parts 5, and this structure serves as a skeleton to support the shape of the insulating material 70, thereby enabling it to obtain high strength.

[0127] Similarly, in the thermal insulation material 70, the welded parts 5 on the outer peripheral surface of the organic fibers 1 also fix the inorganic particles 4 to the organic fibers 1, so that an even greater effect of suppressing powder falling can be obtained. Therefore, for example, even if a portion of the battery cells 20a, 20b, and 20c expands during charging and discharging, causing compressive stress or impact on the heat transfer suppressing member, in this embodiment, the shape of the thermal insulation material 70 can be maintained due to the effects of the welded parts 5 and the frame 53. As a result, it is possible to suppress the inorganic particles 4 from falling off (powder falling), and to prevent a decrease in the insulating effect of the thermal insulation material 70 due to compressive deformation.

[0128] The mechanism by which the insulating material 70 can prevent the inorganic particles 4 from falling off from the sheet surface is believed to be similar to that of the insulating material 60 of Structural Example 3 above.

[0129] In the heat insulating material 70, the welded parts 5 do not need to completely cover the outer circumferential surface of the organic fibers 1, and there may be some areas where the welded parts 5 are not present. Even in such a case, the effect of holding the inorganic particles 4 can be sufficiently obtained.

[0130] Furthermore, since the insulating material 70 contains organic fibers 1 that have high flexibility, the flexibility of the insulating material 70 can be increased and the organic fibers 1 can be easily entangled with each other, which has the effect of improving the sheet strength.

[0131] Furthermore, the heat insulating material 70 has a plurality of holes 7 in the matrix 14 and has voids 8 between the plurality of organic fibers 1 constituting the fiber bundle 6, so that the heat insulating performance can be improved. In addition, due to the presence of the voids 8, the organic fibers 1 are less likely to be constrained in the matrix 14, so that the flexibility and strength of the heat insulating material 70 can be further improved. The voids 8 do not need to be formed in the entire area between the plurality of organic fibers 1, and as long as the voids 8 are formed in at least a part of the areas between the organic fibers 1, the effect of suppressing heat transfer can be obtained. Note that, as shown in the second and fourth embodiments, if the heat insulating material has voids 54 on the main surface side, the effect of suppressing heat transfer can be further improved.

[0132] Furthermore, since the insulating material 70 has the fiber bundles 6 and the fiber layer 11, it is possible to obtain a much higher strength than when the organic fibers 1 are arranged in a dispersed manner. Moreover, the fiber layer 11 is not simply arranged on the base layer 13, but has a composite layer 12 between the fiber layer 11 and the base layer 13 in which a part of the fiber layer 11 and a part of the inorganic particles 4 constituting the matrix 14 are mixed, so that the fiber layer 11 is securely bound to the surface of the insulating material 70. Therefore, it is possible to obtain an insulating material 70 having high strength.

[0133] <Thermal insulation (Structure example 5)> Fig. 17 is a schematic diagram showing a fifth structural example of a heat insulating material used in a heat-transfer suppressing member according to an embodiment of the present invention, and Fig. 18 is a schematic diagram showing an enlarged view of part A of the heat insulating material shown in Fig. 17. In the fifth structural example shown in Figs. 17 and 18, the same components as those in the first structural example of the heat insulating material shown in Figs. 8 and 9 are given the same reference numerals, and detailed descriptions thereof will be omitted.

[0134] As shown in Figs. 17 and 18, the heat insulating material 80 has a matrix 14 containing inorganic particles 4, inorganic fibers 15 dispersed in the matrix 14, and organic fibers 1. The organic fibers 1 and the inorganic fibers 15 are entangled with each other to form a three-dimensional web structure. In this embodiment, an air layer 28 is formed in a part around the inorganic fibers 15. The organic fibers 1 have a welded portion 5 on a part of the surface, and at least a part of the inorganic fibers 15 is welded to the organic fibers 1 by the welded portion 5. Furthermore, at least a part of the inorganic particles 4 is welded to the organic fibers 1 by the welded portion 5.

[0135] In this specification, the term "dispersed" of the inorganic fibers 15 refers to a state in which the inorganic fibers 15 are not distributed unevenly, but are spread out over the entire surface.

[0136] In the insulating material 80 configured in this manner, the organic fibers 1 and the inorganic fibers 15 are intertwined with each other to form a three-dimensional web structure, and this structure serves as a skeleton, thereby providing high strength. Therefore, even if the heat transfer suppressing member is compressed due to the expansion of the battery cells during charging and discharging of the battery cells 20a, 20b, and 20c, the shape of the insulating material 80 can be maintained due to the effect of the skeleton structure of the organic fibers 1 and the inorganic fibers 15 and the frame 53. As a result, it is possible to prevent the inorganic particles 4 from falling off (powdering), and to prevent a decrease in the insulating effect of the insulating material 80 due to compression deformation.

[0137] Furthermore, since the heat insulating material 80 contains the organic fibers 1 having high flexibility, the flexibility of the heat insulating material 80 can be increased, and the organic fibers 1 are easily entangled with the inorganic fibers 15 to form a three-dimensional web structure, thereby improving the strength. Furthermore, if the inorganic fibers 15 are contained in the heat insulating material 80, for example, when the battery cell 20a experiences thermal runaway and the heat-transfer-suppressing member disposed adjacent to the battery cell 20a is exposed to high temperatures, the shape of the heat-transfer-suppressing member can be maintained even if the organic fibers 1 are decomposed. Therefore, by having the heat insulating material 80 contain the organic fibers 1 having high flexibility and the inorganic fibers 15 that do not decompose even at high temperatures, it is possible to obtain a heat-transfer-suppressing member that has a good balance between flexibility and strength.

[0138] Furthermore, in this embodiment, an air layer 28 is provided around the inorganic fibers 15 dispersed in the matrix 14. The inorganic fibers 15 have a higher thermal conductivity than the organic fibers 1, but as described above, the air layer 28 is formed around the inorganic fibers 15, thereby suppressing heat transfer between the inorganic fibers 15 and the matrix 14. The air layer 28 is formed in the manufacturing process of the heat insulating material 80, but it is not necessary for the air layer 28 to be formed around the entire area around the inorganic fibers 15. As long as the air layer 28 is formed on at least a part of the outer circumferential surface of the inorganic fibers 15, the effect of suppressing heat transfer can be obtained.

[0139] When the inorganic fibers 15 are uniformly dispersed in the matrix 14, the air layers 28 in the matrix 14 are also uniformly dispersed and disposed, so that the heat insulating material 80 can obtain high heat insulating properties evenly. Note that, as shown in the second and fourth embodiments, when the heat insulating material has voids 54 on the main surface side, even higher heat insulating properties can be obtained.

[0140] Furthermore, in the insulating material 80, the organic fibers 1 have welded parts 5 covering at least a part of the surface. The "welded parts 5" refer to the parts where the surfaces of the organic fibers 1 melt and then solidify again, and are formed during the manufacturing process of the insulating material 80. When at least a part of the inorganic fibers 15 is welded to the organic fibers 1 by the welded parts 5, the entangled organic fibers 1 and the inorganic fibers 15 are fixed, so that an insulating material 80 with even higher strength can be obtained.

[0141] Similarly, in this embodiment, the welded portion 5 on the outer peripheral surface of the organic fiber 1 also fixes the inorganic particles 4 to the organic fiber 1, thereby achieving an even greater powder fall-off suppression effect. Therefore, for example, even if a portion of the battery cells 20a, 20b, and 20c expands and applies a compressive stress or impact to the heat transfer suppressing member, excellent heat insulation performance can be maintained.

[0142] In this embodiment, the mechanism by which the inorganic particles 4 can be prevented from falling off from the sheet surface is believed to be that the organic fibers 1 and the inorganic fibers 15 are welded by the welded parts 5 to form a three-dimensional, strong skeleton, which maintains the shape of the insulating material 80 and prevents deformation or compression of the heat-transfer suppressing member. Furthermore, regardless of the presence or absence of the elastic material 51 on the surface of the insulating material 80, when the organic fibers 1 and the inorganic fibers 15 are exposed on the surface of the insulating material 80, it is believed that the impact given to the insulating material 80 can be absorbed and the inorganic particles 4 are held in place.

[0143] Furthermore, in this embodiment, for example, a heat insulating material with a low elastic modulus is disposed in an area where the deformation of the battery cell is large. In addition, if the heat insulating material is formed to be thinner than the frame body 53 or if an elastic material is laminated on the heat insulating material, it is possible to absorb impacts given to the heat insulating material, similar to the effect of the fiber portion 16, and the effect of holding the inorganic particles 4 can be improved.

[0144] In the heat insulating material 80, the welded parts 5 do not need to completely cover the outer circumferential surface of the organic fibers 1, and there may be some areas where the welded parts 5 are not present. Even in such a case, the effect of holding the inorganic particles 4 can be sufficiently obtained.

[0145] <Thermal insulation (Structure example 6)> Fig. 19 is a photograph substituting a drawing showing a sixth structural example of a heat insulating material used in a heat-transfer suppressing member according to an embodiment of the present invention, and Fig. 20 is a photograph substituting a drawing showing another region of the heat insulating material shown in Fig. 19. Also, Fig. 21 is a photograph substituting a drawing showing a cross section of the heat insulating material shown in Figs. 19 and 20. In Structural example 6 shown in Figs. 19 to 21, the same components as those in structural example 4 of the heat insulating material shown in Figs. 14 to 16 are given the same reference numerals and detailed description thereof will be omitted.

[0146] 19, the heat insulating material 90 includes inorganic particles 4 and organic fibers 1. At least some of the organic fibers 1 have a branched structure including a base 32 and branches 33 extending from the base 32. In this embodiment, the branches 33 extend from the base 32 in four directions, namely, directions D1, D2, D3, and D4. The base 32 and the multiple branches 33 form a skeleton.

[0147] 20 also contains organic fibers 1 having a branched structure consisting of a base 32 and branches 33 extending from the base 32. The organic fibers 1 shown in FIG 20 each have a base 32 and branches 33 extending from the base 32 in five directions, namely, directions D1, D2, D3, D4, and D5, and the base 32 is thicker than the multiple branches 33.

[0148] Furthermore, in this embodiment, as shown in FIGS. 19 and 20, inorganic particles 4 are fused to the surface of the organic fiber 1, so that the surface of the organic fiber 1 is covered with the inorganic particles 4.

[0149] As shown in the cross-sectional view of Fig. 21, a plurality of voids 7 are formed in the heat insulating material 90. Furthermore, in the heat insulating material 90, a fiber bundle 6 is formed by at least partially welding a plurality of organic fibers 1 to each other, and gaps 8 are formed between the plurality of organic fibers 1 constituting the fiber bundle 6. Note that, also in Fig. 21, it is possible to confirm the organic fibers 1 having a branched structure consisting of a base 32 and branches 33 extending in three directions from the base 32.

[0150] Furthermore, a fiber layer 11 may be formed on at least a part of the first surface and the second surface perpendicular to the thickness direction of the heat insulating material 90. The fiber layer 11 is formed in a layer on the surface (first surface and second surface) of the heat insulating material 90 by welding at least a part of the organic fibers 1 to each other. In addition, a composite layer 12 may be formed between the fiber layer 11 and the base layer 13 containing the inorganic particles 4 and the organic fibers 1. The composite layer 12 is a layer in which a part of the fiber layer 11 and a part of the inorganic particles 4 are mixed. Specifically, the composite layer 12 is a region containing a plurality of organic fibers 1 welded to each other and the inorganic particles 4 welded to the organic fibers 1.

[0151] The fiber bundles 6 are formed by entangling 10 or more organic fibers 1 with one another and by welding the organic fibers 1 to one another in some places, and are arranged in an arbitrary direction inside the thermal insulation material 90. On the other hand, the fiber layer 11 is a layer formed by assembling 10 or more organic fibers 1 on the surface of the thermal insulation material 90, and extends, for example, in stripes in a direction substantially parallel to the surface.

[0152] In the heat insulating material 90 configured in this manner, at least a portion of the organic fibers 1 has a branched structure consisting of a base 32 and a branch 33, and therefore the organic fibers 1 serve as a skeleton to maintain the shape of the heat insulating material 90. In this embodiment, the base 32 is configured by a fused portion in which the organic fibers 1 are fused to each other. Specifically, the base 32 is a portion in which a plurality of organic fibers 1 are brought into contact with each other, melted together, and then solidified, and is therefore thicker than the branch 33. Therefore, the entire skeleton can be firmly supported by the base 32, and the strength of the heat insulating material 90 can be significantly improved.

[0153] In the thermal insulation material 90, at least a part of the organic fibers 1 has a branched structure consisting of a base 32 and branches 33 extending from the base 32 in at least three directions. The branched structure can be confirmed in a cross-sectional photograph of the thermal insulation material 90, but an easier way to confirm the branched structure is to observe a cross-section of the thermal insulation material 90 torn in a plane direction perpendicular to its thickness direction. In this way, by observing the cross-section, it is possible to easily confirm that the organic fibers 1 have a branched structure consisting of a base 32 and branches 33 extending from the base 32 in at least three directions. The base 32 and the branches 33 will be described in more detail below.

[0154] (Base (fusion part)) The fused portion is formed when the sheath portion of the binder fiber is heated and melted once and then cooled in a portion where a plurality of binder fibers are in contact with each other when a binder fiber with a core-sheath structure is used as the material of the thermal insulation material 90. When a binder fiber with a core-sheath structure is used as the material of the thermal insulation material 90, the fused portion contains the second organic material that constitutes the sheath portion. In this manner, in the manufacturing process of the heat transfer suppressing member, when the sheath in the region where multiple binder fibers are in contact is melted by heating, the amount of melted sheath (second organic material) is greater than when the sheath of a single binder fiber is melted, and a thick fused portion (base 32) is formed after cooling. As a result, the skeleton is firmly supported by base 32.

[0155] (branch) The support parts 33 extend in at least three directions from the base part 32 and have the effect of holding the inorganic particles 4. In addition, the base part 32 and the support parts 33 form a skeleton, which can also improve the strength of the heat-transfer suppressing member. This makes it possible to obtain a high powder-fall suppression effect. When a binder fiber having a core-sheath structure is used as the organic fiber 1, the branch 33 is a part of the binder fiber having a core-sheath structure, and has a core made of a first organic material and a sheath made of a second organic material.

[0156] As long as the branches 33 extending from the base 32 extend in at least three directions, a skeleton made of the organic fibers 1 can be formed. In addition, it is preferable that these multiple branches 33 each extend in a different three-dimensional direction, which allows a three-dimensional, strong skeleton to be formed.

[0157] In the above-mentioned heat insulating material 90, since a plurality of support parts 33 extend from the base part 32, the inorganic particles 4 can be held by these support parts 33, and a high powder fall suppression effect can be obtained by a synergistic effect with the effect of improving the sheet strength by forming a skeleton. Therefore, for example, even if a part of the battery cells 20a, 20b, 20c expands during charging and discharging, causing compressive stress or impact on the heat transfer suppressing member, the shape of the heat insulating material 90 can be maintained by the effect of the skeleton structure of the heat insulating material 90 and the frame body 53 of the heat transfer suppressing member. As a result, it is possible to suppress the inorganic particles 4 from falling off (powder fall), and to prevent a decrease in the insulating effect of the heat insulating material 90 due to compression deformation.

[0158] The mechanism by which the inorganic particles 4 can be prevented from falling off from the surface of the insulating material 90 is thought to be the same as the insulating material 60 of Structural Example 3 above, as well as the effect of the support parts 33 holding the inorganic particles 4. Furthermore, when the inorganic particles 4 are fused to the surface of the organic fibers 1, the organic fibers 1 appear to have a thicker fiber diameter, so that the strength of the organic fibers 1 is higher than that of the organic fibers 1 alone, and a high holding effect of the inorganic particles 4 can be obtained.

[0159] In the heat insulating material 90, there may be a region where the inorganic particles 4 are not partially welded to the outer peripheral surface of the organic fibers 1. Even in such a case, the effect of holding the inorganic particles 4 can be sufficiently obtained.

[0160] Furthermore, since the insulating material 90 contains organic fibers 1 that have high flexibility, the flexibility of the insulating material 90 can be increased and the organic fibers 1 can be easily entangled with each other, which has the effect of improving the sheet strength.

[0161] Furthermore, the heat insulating material 90 preferably has a plurality of holes 7 and also has gaps 8 between the plurality of organic fibers 1 constituting the fiber bundle 6, thereby obtaining the effect of air insulation and improving the heat insulating performance. In addition, the presence of the gaps 8 makes the organic fibers 1 completely unconstrained, so that the flexibility and strength of the heat insulating material 90 can be further improved. The gaps 8 do not need to be formed in the entire area between the plurality of organic fibers 1, and as long as the gaps 8 are formed in at least a part of the organic fibers 1, the effect of suppressing heat transfer can be obtained. Note that, as shown in the second and fourth embodiments, if the heat insulating material has gaps 54 on the main surface side, even higher heat insulating properties can be obtained.

[0162] Furthermore, since the insulating material 90 has the fiber bundles 6 and the fiber layer 11, it is possible to obtain a sheet strength that is even higher than when the organic fibers 1 are arranged in a dispersed manner. Furthermore, when the fiber layer 11 is present, the fiber layer 11 is not simply arranged on the base layer 13, but has a composite layer 12 between the fiber layer 11 and the base layer 13 in which part of the fiber layer 11 and part of the inorganic particles 4 are mixed, so that the fiber layer 11 is securely bound to the surface of the insulating material 90. Therefore, the strength of the insulating material 90 can be improved.

[0163] <Thermal insulation (Structure example 7)> Fig. 22 is a photograph substituting a drawing showing a seventh structural example of a heat insulating material used in a heat-transfer suppressing member according to an embodiment of the present invention, and Fig. 23 is a photograph substituting a drawing showing an enlarged portion of the heat insulating material shown in Fig. 22. In Structural example 7 shown in Figs. 22 and 23, the same components as those in structural example 2 of the heat insulating material shown in Fig. 10 are given the same reference numerals and detailed descriptions thereof will be omitted.

[0164] 22 and 23, the thermal insulation material 110 has inorganic particles 4 and organic fibers 1. A first region 42 having streak-like fiber bundles 47 made of a plurality of organic fibers 1 and a second region 43 in which no fiber bundles 47 are present are formed on the surface of the thermal insulation material 110. In this specification, the "fiber bundles 47" are 10 or more organic fibers 1 intertwined with each other, and extend in a streak-like manner in a direction approximately parallel to the surface of the thermal insulation material 110.

[0165] That is, when the surface of the thermal insulation material 110 is observed, a state in which a plurality of organic fibers 1 are entangled is observed in the first region 42, as shown in Fig. 23. On the other hand, in the second region 43, although there are some places where a few organic fibers 1 are observed, fiber bundles 47 in which a plurality of organic fibers 1 are entangled are not observed. In this embodiment, the first region 42 and the second region 43 have a sea-island structure, and the second region 43 corresponding to an island portion is formed so as to be surrounded by the first region 42 corresponding to a sea portion.

[0166] In the heat insulating material 110, fiber bundles 47 in which the organic fibers 1 are entangled are present on the surface of the heat insulating material 110 in a streaky manner, so that the strength of the heat insulating material 110 can be improved. In addition, the entire surface is not covered with the fiber bundles 47, and there are a first region 42 in which the fiber bundles 47 are present and a second region in which the fiber bundles 47 are not present, so that the flexibility of the heat insulating material 110 is also excellent. Furthermore, in this embodiment, for example, a heat insulating material having a low elastic modulus is disposed in a region in which the deformation of the battery cell is large, and the above-mentioned fiber bundles 47 are present on the surface of the heat insulating material 110. Therefore, even if an impact or pressure is applied to the heat insulating material 110, the heat insulating material and the fiber bundles 47 can absorb and mitigate the impact or pressure. Therefore, it is possible to suppress the inorganic particles 4 from falling off (powdering off), and to prevent a decrease in the heat insulating performance of the heat transfer suppressing member.

[0167] In the heat insulating material 110, the organic fibers 1 and the fiber bundles 47 in which the organic fibers 1 are entangled are present not only on the surface of the heat insulating material 110 but also inside the heat insulating material 110. This makes it possible to obtain even greater strength.

[0168] It is preferable that the length of the fiber bundles 47 formed so as to extend over the surface of the heat insulating material 110 is relatively long. An example of a method for determining the length of the fiber bundles 47 will be described with reference to FIG. 24, rectangular imaginary frames 21 are arranged along the streak-like fiber bundles 47 on the surface of the thermal insulation material 110. In this embodiment, the size of the imaginary frames 21 is 5 mm square, and these imaginary frames 21 are arranged so as to be continuous with each other. In this case, if there are fiber bundles 47 that penetrate at least three continuous imaginary frames 21, it can be determined that the effect of improving the strength of the thermal insulation material 110 is sufficient.

[0169] It is also possible to simply measure the length of the fiber bundles 47 extending in a stripe shape. For example, a method can be used in which a string or the like is placed on the surface of the thermal insulation material 110 along the fiber bundles 47, and then the length of the string is measured. When the length of continuous fiber bundles 47 is measured, if there are fiber bundles 47 with a length of 20 mm or more, the effect of improving the strength of the thermal insulation material 110 can be sufficiently obtained.

[0170] Furthermore, as shown in FIG. 25, if the fiber bundles 47 are connected in a mesh pattern on the surface of the heat insulating material 110, the sheet strength can be further improved.

[0171] The materials constituting the heat insulating materials of Structural Examples 1 to 7 and the preferred contents thereof will be described in more detail below.

[0172] <Organic fiber> The organic fiber 1 gives flexibility to the heat insulating material, and has the effect of maintaining the strength and shape of the sheet by welding the inorganic particles 4 and other organic fibers 1 to the surface of the organic fiber 1. Although a single-component organic fiber can be used as the material of the organic fiber 1 in the heat insulating material, it is preferable to use a binder fiber with a core-sheath structure. The binder fiber with a core-sheath structure has a core extending in the longitudinal direction of the fiber and a sheath formed to cover the outer peripheral surface of the core. In addition, the core is made of a first organic material, the sheath is made of a second organic material, and the melting point of the first organic material is higher than the melting point of the second organic material. When the binder fiber with a core-sheath structure is used as a material, the core corresponds to the organic fiber 1 in the heat insulating material. In addition, during the production of the heat insulating material, the second organic material constituting the sheath melts and then solidifies again, so that the sheath becomes the welded part 5 in the heat insulating material.

[0173] When a binder fiber having a core-sheath structure is used as the material of the organic fiber 1, the core, i.e., the first organic material constituting the organic fiber 1, is not particularly limited as long as it has a melting point higher than that of the sheath, i.e., the second organic material present on the outer peripheral surface of the organic fiber 1. The first organic material may be at least one selected from polyethylene terephthalate, polypropylene, and nylon.

[0174] (Organic fiber content) In this embodiment, if the content of the organic fiber 1 in the heat insulating material is appropriately controlled, the effect of reinforcing the skeleton can be sufficiently obtained. The content of the organic fibers 1 is preferably 2% by mass or more, more preferably 4% by mass or more, based on the total mass of the heat insulating material. If the content of the organic fibers 1 is too high, the content of the inorganic particles 4 will relatively decrease, so in order to obtain the desired heat insulating performance, the content of the organic fibers is preferably 10% by mass or less, more preferably 8% by mass or less, based on the total mass of the heat insulating material.

[0175] (Organic fiber length) The fiber length of the organic fibers 1 is not particularly limited, but from the viewpoint of ensuring moldability and processability, it is preferable that the average fiber length of the organic fibers is 10 mm or less. On the other hand, from the viewpoint of making the organic fibers 1 function as a skeleton and ensuring the compressive strength of the heat insulating material, it is preferable that the average fiber length of the organic fibers 1 is 0.5 mm or more.

[0176] <Welded part> The welded portion 5 is formed by heating and melting the surface of the organic fiber 1 or the sheath of the binder fiber having a core-sheath structure, and then cooling it, and serves to weld the inorganic particles 4 to the surface of the organic fiber 1 and also to weld the organic fibers 1 together. When a binder fiber having a core-sheath structure is used as the material for the organic fiber 1, the welded portion 5 contains the second organic material that constitutes the sheath.

[0177] (Second organic material) The second organic material is not particularly limited as long as it has a melting point lower than that of the first organic material constituting the organic fiber 1. The second organic material may be at least one selected from the group consisting of polyethylene terephthalate, polyethylene, polypropylene, and nylon. The melting point of the second organic material is preferably 90° C. or higher, and more preferably 100° C. or higher. The melting point of the second organic material is preferably 150° C. or lower, and more preferably 130° C. or lower.

[0178] <Inorganic particles> As the inorganic particles, a single inorganic particle may be used, or two or more types of inorganic particles may be used in combination. As the type of inorganic particles, from the viewpoint of the heat transfer suppression effect, it is preferable to use particles made of at least one inorganic material selected from oxide particles, carbide particles, nitride particles, and inorganic hydrate particles, and it is more preferable to use oxide particles. In addition, the shape is not particularly limited, but it is preferable to include at least one selected from nanoparticles, hollow particles, and porous particles, and specifically, silica nanoparticles, metal oxide particles, inorganic balloons such as microporous particles and hollow silica particles, particles made of thermally expandable inorganic materials, particles made of water-containing porous bodies, etc. can also be used.

[0179] If the average secondary particle diameter of the inorganic particles is 0.01 μm or more, they are easily available and the increase in production costs can be suppressed. If the average secondary particle diameter is 200 μm or less, the desired heat insulating effect can be obtained. Therefore, the average secondary particle diameter of the inorganic particles is preferably 0.01 μm or more and 200 μm or less, and more preferably 0.05 μm or more and 100 μm or less.

[0180] In addition, when two or more kinds of inorganic particles having different heat transfer suppression effects are used in combination, the heating body can be cooled in multiple stages, and the heat absorption effect can be expressed in a wider temperature range. Specifically, it is preferable to use a mixture of large-diameter particles and small-diameter particles. For example, when nanoparticles are used as one inorganic particle, it is preferable to include inorganic particles made of metal oxide as the other inorganic particle. Hereinafter, the inorganic particles will be described in more detail, with the small-diameter inorganic particles being referred to as the first inorganic particles and the large-diameter inorganic particles being referred to as the second inorganic particles.

[0181] <First inorganic particle> (Oxide particles) Since oxide particles have a high refractive index and a strong effect of scattering light, when oxide particles are used as the first inorganic particles, radiation heat transfer can be suppressed, particularly in high temperature regions such as abnormal heat generation. As the oxide particles, at least one type of particle selected from silica, titania, zirconia, zircon, barium titanate, zinc oxide, and alumina can be used. That is, among the above oxide particles that can be used as inorganic particles, only one type may be used, or two or more types of oxide particles may be used. In particular, silica is a component with high heat insulation properties, and titania is a component with a high refractive index compared to other metal oxides, and has a high effect of scattering light and blocking radiant heat in high temperature regions of 500°C or more, so it is most preferable to use silica and titania as the oxide particles.

[0182] (Average primary particle size of oxide particles: 0.001 μm to 50 μm) The particle size of the oxide particles can affect the effect of reflecting radiant heat, so if the average primary particle size is limited to a predetermined range, even higher heat insulation can be obtained. In other words, when the average primary particle diameter of the oxide particles is 0.001 μm or more, it is sufficiently larger than the wavelength of light that contributes to heating and efficiently diffuses the light, thereby suppressing the radiation heat transfer within the insulation material in the high temperature range of 500°C or more, thereby further improving the insulation properties. On the other hand, if the average primary particle size of the oxide particles is 50 μm or less, the number and number of contact points between the particles do not increase even when compressed, making it difficult to form a conductive heat transfer path, thereby reducing the impact on insulation, especially in the normal temperature range where conductive heat transfer is dominant.

[0183] In the present invention, the average primary particle size can be determined by observing particles under a microscope, comparing with a standard scale, and taking the average of any ten particles.

[0184] (Nanoparticles) In the present invention, the term "nanoparticles" refers to particles of the order of nanometers that are spherical or nearly spherical and have an average primary particle diameter of less than 1 μm. Nanoparticles have a low density and therefore suppress conductive heat transfer. When nanoparticles are used as the first inorganic particles, the three-dimensionally connected pores 7 are further refined, and excellent heat insulation properties that suppress convective heat transfer can be obtained. For this reason, it is preferable to use nanoparticles in that heat transfer between adjacent nanoparticles can be suppressed when the battery is used in the normal room temperature range. Furthermore, if nanoparticles with a small average primary particle size are used as the oxide particles, the increase in conductive heat transfer of the insulating material can be suppressed even if the insulating material is compressed due to expansion caused by thermal runaway of the battery cell and the internal density increases. This is thought to be because nanoparticles are prone to forming fine gaps between particles due to electrostatic repulsion, and because they have a low bulk density, the particles are packed together to provide cushioning properties.

[0185] In the present invention, when nanoparticles are used as the first inorganic particles, there is no particular limitation on the material as long as it meets the above definition of nanoparticles. For example, silica nanoparticles are a material with high heat insulation properties, and since the contact points between particles are small, the amount of heat conducted by silica nanoparticles is smaller than that when silica particles with a large particle size are used. Furthermore, silica nanoparticles that are generally available have a bulk density of 0.1 (g / cm 3), for example, even if the battery cells arranged on both sides of the insulating material thermally expand and a large compressive stress is applied to the insulating material, the size (area) and number of contacts between the silica nanoparticles do not increase significantly, and the insulating properties can be maintained. Therefore, it is preferable to use silica nanoparticles as the nanoparticles. Examples of silica nanoparticles include wet silica, dry silica, and aerogel, but silica nanoparticles that are particularly suitable for this embodiment will be described below.

[0186] Generally, wet silica particles are aggregated, whereas dry silica particles can be dispersed. In the temperature range below 300℃, heat conduction is dominated by conductive heat transfer, so dry silica particles can be dispersed, which provides better heat insulation performance than wet silica. In addition, the heat insulating material according to the present embodiment is preferably produced by a manufacturing method in which a mixture containing the material is processed into a sheet shape by a dry method. Therefore, it is preferable to use dry silica, silica aerogel, or the like, which has low thermal conductivity, as the inorganic particles.

[0187] (Average primary particle size of nanoparticles: 1 nm to 100 nm) By limiting the average primary particle size of the nanoparticles to a predetermined range, even higher heat insulation properties can be obtained. That is, when the average primary particle size of the nanoparticles is 1 nm or more and 100 nm or less, it is possible to suppress convective heat transfer and conductive heat transfer within the insulating material, particularly in the temperature range below 500° C., and to further improve the insulating properties. Even when compressive stress is applied, the gaps remaining between the nanoparticles and the contact points between many particles suppress conductive heat transfer, and the insulating properties of the insulating material can be maintained. The average primary particle size of the nanoparticles is more preferably 2 nm or more, and even more preferably 3 nm or more, while the average primary particle size of the nanoparticles is more preferably 50 nm or less, and even more preferably 10 nm or less.

[0188] (Inorganic hydrate particles) When inorganic hydrate particles receive heat from a heating element and reach a temperature above the thermal decomposition initiation temperature, they undergo thermal decomposition and release their own water of crystallization to lower the temperature of the heating element and its surroundings, thus exerting the so-called "endothermic effect". After releasing the water of crystallization, the particles become porous and exert a heat insulating effect due to the countless air holes. A specific example of an inorganic hydrate is aluminum hydroxide (Al(OH) 3 ), magnesium hydroxide (Mg(OH) 2 ), calcium hydroxide (Ca(OH) 2 ), zinc hydroxide (Zn(OH) 2 ), iron hydroxide (Fe(OH) 2 ), manganese hydroxide (Mn(OH) 2 ), zirconium hydroxide (Zr(OH) 2 ), gallium hydroxide (Ga(OH) 3 ) etc.

[0189] For example, aluminum hydroxide contains about 35% water of crystallization, and as shown in the following formula, it decomposes thermally and releases the water of crystallization, thereby exerting an endothermic effect. After releasing the water of crystallization, it becomes a porous alumina (Al 2 O 3 ) and acts as a thermal insulator. 2Al(OH) 3 →Al 2 O 3 +3H 2 O

[0190] It should be noted that the heat transfer suppressing member according to this embodiment is preferably interposed between battery cells, for example, but in a battery cell that has experienced thermal runaway, the temperature rises rapidly to over 200° C. and continues to rise to around 700° C. Therefore, it is preferable that the inorganic particles be made of an inorganic hydrate whose thermal decomposition onset temperature is 200° C. or higher. The thermal decomposition onset temperatures of the inorganic hydrates listed above are approximately 200°C for aluminum hydroxide, approximately 330°C for magnesium hydroxide, approximately 580°C for calcium hydroxide, approximately 200°C for zinc hydroxide, approximately 350°C for iron hydroxide, approximately 300°C for manganese hydroxide, approximately 300°C for zirconium hydroxide, and approximately 300°C for gallium hydroxide. All of these temperatures roughly overlap with the temperature range of the sudden temperature rise in a battery cell that has experienced thermal runaway, and can efficiently suppress the temperature rise, making these inorganic hydrates preferable.

[0191] (Average secondary particle diameter of inorganic hydrate particles: 0.01 μm or more and 200 μm or less) In addition, when inorganic hydrate particles are used as the first inorganic particles, if the average particle size is too large, the first inorganic particles (inorganic hydrate) near the center of the heat insulating material require a certain amount of time to reach their thermal decomposition temperature, and the first inorganic particles near the center of the sheet may not be completely thermally decomposed. For this reason, the average secondary particle size of the inorganic hydrate particles is preferably 0.01 μm or more and 200 μm or less, and more preferably 0.05 μm or more and 100 μm or less.

[0192] (Particles made of thermally expandable inorganic material) Examples of the thermally expandable inorganic material include vermiculite, bentonite, mica, and perlite.

[0193] (Particles made of water-containing porous material) Specific examples of the hydrous porous body include zeolite, kaolinite, montmorillonite, acid clay, diatomaceous earth, wet silica, dry silica, aerogel, mica, and vermiculite.

[0194] (Inorganic balloon) The heat insulating material used in the present invention may contain inorganic balloons as the first inorganic particles. When inorganic balloons are contained, convective or conductive heat transfer within the insulating material can be suppressed in the temperature range below 500° C., and the insulating properties of the insulating material can be further improved. As the inorganic balloons, at least one selected from the group consisting of shirasu balloons, silica balloons, fly ash balloons, barite balloons, and glass balloons can be used.

[0195] (Inorganic balloon content: 60% or less by mass of the total mass of the insulation material) The content of the inorganic balloons is preferably 60 mass % or less based on the total mass of the heat insulating material.

[0196] (Average particle size of inorganic balloons: 1 μm to 100 μm) The average particle size of the inorganic balloons is preferably 1 μm or more and 100 μm or less.

[0197] <Second inorganic particles> When two types of inorganic particles are contained in the heat insulating material, the second inorganic particles are not particularly limited as long as they are different from the first inorganic particles in terms of material, particle size, etc. As the second inorganic particles, oxide particles, carbide particles, nitride particles, inorganic hydrate particles, silica nanoparticles, metal oxide particles, inorganic balloons such as microporous particles and hollow silica particles, particles made of a thermally expandable inorganic material, particles made of a water-containing porous body, etc. can be used, and the details of these are as described above.

[0198] In addition, nanoparticles have extremely low conductive heat transfer and can maintain excellent heat insulation even when compressive stress is applied to the heat insulating material. Metal oxide particles such as titania have a high effect of blocking radiant heat. Furthermore, when large-diameter inorganic particles and small-diameter inorganic particles are used, the small-diameter inorganic particles enter the gaps between the large-diameter inorganic particles, resulting in a denser structure and improving the heat transfer suppression effect. Therefore, when nanoparticles are used as the first inorganic particles, for example, it is preferable to further include particles made of a metal oxide larger in diameter than the first inorganic particles as the second inorganic particles in the heat insulating material. Examples of metal oxides include silicon oxide, titanium oxide, aluminum oxide, barium titanate, zinc oxide, zircon, zirconium oxide, etc. In particular, titanium oxide (titania) is a component with a higher refractive index than other metal oxides, and is highly effective in scattering light and blocking radiant heat in a high temperature range of 500°C or higher, so it is most preferable to use titania.

[0199] When at least one type of particles selected from dry silica particles and silica aerogel is used as the first inorganic particles, and at least one type of particles selected from titania, zircon, zirconia, silicon carbide, zinc oxide and alumina is used as the second inorganic particles, in order to obtain excellent heat insulating performance within a temperature range of 300° C. or less, the first inorganic particles are preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more of the total mass of the inorganic particles. In addition, the first inorganic particles are preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 80% by mass or less of the total mass of the inorganic particles.

[0200] On the other hand, in order to obtain excellent heat insulating performance within a temperature range exceeding 300° C., the second inorganic particles are preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more, based on the total mass of the inorganic particles. Also, the second inorganic particles are preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less, based on the total mass of the inorganic particles.

[0201] (Average primary particle size of second inorganic particles) When second inorganic particles made of a metal oxide are contained in a heat insulating material, if the average primary particle size of the second inorganic particles is 1 μm or more and 50 μm or less, radiation heat transfer can be efficiently suppressed in a high temperature range of 500° C. or more. The average primary particle size of the second inorganic particles is more preferably 5 μm or more and 30 μm or less, and most preferably 10 μm or less.

[0202] (Inorganic particle content) In this embodiment, when the total content of the inorganic particles 4 in the heat insulating material is appropriately controlled, the heat insulating property of the heat insulating material can be sufficiently ensured. The total content of the inorganic particles 4 is preferably 60% by mass or more, and more preferably 70% by mass or more, based on the total mass of the heat insulating material. If the total content of the inorganic particles 4 is too high, the content of the organic fibers is relatively reduced, so that in order to sufficiently obtain the effect of reinforcing the skeleton and the effect of retaining the inorganic particles, the total content of the inorganic particles 4 is preferably 95% by mass or less, and more preferably 90% by mass or less, based on the total mass of the heat insulating material.

[0203] The content of the inorganic particles 4 in the heat insulating material can be calculated, for example, by heating the heat insulating material at 800° C., decomposing the organic matter, and then measuring the mass of the remaining part.

[0204] <Inorganic fibers> A single inorganic fiber may be used, or two or more types of inorganic fibers may be used in combination as the inorganic fiber 15. Examples of the inorganic fiber include ceramic fibers such as silica fiber, alumina fiber, alumina silicate fiber, zirconia fiber, carbon fiber, soluble fiber, refractory ceramic fiber, aerogel composite material, magnesium silicate fiber, alkaline earth silicate fiber, potassium titanate fiber, silicon carbide fiber, and potassium titanate whisker fiber, glass fibers such as glass fibers, glass wool, and slag wool, and mineral fibers other than these fibers such as rock wool, basalt fiber, and mullite fiber, and mineral fibers other than the above such as natural mineral fibers such as wollastonite. These inorganic fibers are preferred in terms of heat resistance, strength, availability, etc. Among the inorganic fibers, silica-alumina fibers, alumina fibers, silica fibers, rock wool, alkaline earth silicate fibers, and glass fibers are particularly preferred in terms of ease of handling.

[0205] The cross-sectional shape of the inorganic fiber is not particularly limited, and examples thereof include a circular cross section, a flat cross section, a hollow cross section, a polygonal cross section, a core cross section, etc. Among them, modified cross section fibers having a hollow cross section, a flat cross section, or a polygonal cross section are preferably used because they have slightly improved heat insulation properties.

[0206] The preferred lower limit of the average fiber length of the inorganic fibers is 0.1 mm, and the more preferred lower limit is 0.5 mm. On the other hand, the preferred upper limit of the average fiber length of the inorganic fibers is 50 mm, and the more preferred upper limit is 10 mm. If the average fiber length of the inorganic fibers is less than 0.1 mm, the inorganic fibers are less likely to be entangled with each other, and the mechanical strength of the insulating material may be reduced. On the other hand, if it exceeds 50 mm, although a reinforcing effect is obtained, the inorganic fibers may not be able to be tightly entangled with each other, or may be curled up with only a single inorganic fiber, which may lead to continuous voids, which may lead to a decrease in thermal insulation.

[0207] The preferred lower limit of the average fiber diameter of the inorganic fibers is 1 μm, more preferably 2 μm, and even more preferably 3 μm. On the other hand, the preferred upper limit of the average fiber diameter of the inorganic fibers is 15 μm, and more preferably 10 μm. If the average fiber diameter of the inorganic fibers is less than 1 μm, the mechanical strength of the inorganic fibers themselves may be reduced. In addition, from the viewpoint of the effect on human health, it is preferable that the average fiber diameter of the inorganic fibers is 3 μm or more. On the other hand, if the average fiber diameter of the inorganic fibers is more than 15 μm, the solid heat transfer through the inorganic fibers may increase, leading to a decrease in heat insulation, and the moldability and strength of the heat insulating material may be deteriorated.

[0208] (Inorganic fiber content) In this embodiment, when the heat insulating material contains inorganic fibers, the content of the inorganic fibers is preferably 3 mass % or more and 15 mass % or less with respect to the total mass of the heat insulating material.

[0209] The content of inorganic fibers is more preferably 5% by mass or more and 10% by mass or less based on the total mass of the heat insulating material. By setting the content at such a level, the shape retention, pressing force resistance, wind pressure resistance, and inorganic particle retention ability of the inorganic fibers are expressed in a well-balanced manner. In addition, by appropriately controlling the content of inorganic fibers, the organic fibers 1 and the inorganic fibers are entangled with each other to form a three-dimensional network, so that the effect of retaining the inorganic particles 4 and other compounding materials described later can be further improved.

[0210] <Other compounding materials> The heat insulating material according to the present embodiment may further contain a binder, a colorant, etc., as necessary. All of these are useful for the purpose of reinforcing the heat insulating material, improving its formability, etc., and the total amount of these is preferably 10 mass % or less based on the total mass of the heat insulating material.

[0211] Although the insulating material Structural Examples 1 to 7 have been described above, the structure of the insulating material containing inorganic particles and organic fibers is not limited thereto, and insulating materials having various structures can be used. In particular, the insulating materials of Structural Examples 1 to 7 have a more excellent insulating effect than other insulating materials and insulating materials containing fibers and aerogel.

[0212] Here, we will explain the results of comparing the insulating effect using various insulating materials of different types and thicknesses. The insulating effect test can be performed by placing a heater in contact with one main surface of the insulating material, placing a thermometer on the other main surface, and measuring the temperature change of the other main surface when the temperature of the heater is increased. When the temperature of the heater is increased to 800°C, the temperature of the other main surface of the insulating material reaches the maximum temperature after a certain period of time. At this time, it can be seen that the insulating material with the lower maximum temperature has better insulating properties. The results of the comparison of insulating effects are shown in Table 1 below.

[0213] [Table 1]

[0214] In Table 1, the heat insulating materials A-1 and A-2 are heat insulating materials of the structural example 3 shown in Figs. 11 to 13, and are obtained by molding organic fibers with a core-sheath structure and inorganic particles into a sheet shape by a dry method. In the heat insulating materials A-1 and A-2, the organic fibers used are those with a core-sheath structure in which the core and sheath are made of polyethylene terephthalate and the melting points of the two differ by 90°C or more, and silica nanoparticles and titania are used as the inorganic particles. The heat insulating material B is made of a fiber framework and SiO 2 It is impregnated with

[0215] As shown in Table 1 above, the insulating performance of the insulating material A-1 with a thickness of 2.0 mm is equal to that of the insulating material B with a thickness of 4.5 mm. Also, when the thickness of the insulating material A-2 is further increased, it is possible to obtain higher insulating performance than the insulating material B with a thinner thickness.

[0216] These results are not limited to Structural Example 3, but similar heat insulating performance can be obtained with all of the heat insulating materials of Structural Examples 1 to 7. Therefore, by using the heat insulating materials of Structural Examples 1 to 7 that contain inorganic particles and organic fibers, excellent heat insulating properties can be obtained. In addition, since the thickness of the heat insulating material can be easily made thinner than the frame 53, it can be particularly suitably used as the heat insulating material for the heat transfer suppressing members shown in the second to fourth embodiments.

[0217] Further, the constituent materials used in the heat transfer suppressing member according to this embodiment, other than the frame, the partition wall, and the insulating material, will be described below.

[0218] <Film> As shown in the above first to fourth embodiments, when the heat transfer suppressing member has a film 52, the material constituting the film 52 can be at least one selected from polyethylene, polypropylene, polystyrene, vinyl chloride, nylon, acrylic, epoxy resin, polyurethane, polyether ether ketone, polyetherimide, polyethylene terephthalate, polytetrafluoroethylene (PTFE), polyphenylsulfide, polycarbonate, and aramid.

[0219] Shrink packaging may be used when only the insulating material is covered with a film, or when the insulating material and the frame, or the entire surface of the laminate and the frame, are covered with film 52. Materials suitable for shrink packaging include polyethylene, polypropylene, polystyrene, polyethylene terephthalate, and polyvinyl chloride.

[0220] (film thickness) The film preferably has an appropriate thickness to prevent particles and the like from falling off the heat insulating material and to prevent the heat insulating material from falling off the frame 53. The film also preferably has appropriate flexibility. If the thickness of the film exceeds 1 mm, the film is prone to cracks and breaks. Therefore, the thickness of the film is preferably 1 mm or less, more preferably 0.1 mm or less, and even more preferably 0.05 mm or less. On the other hand, there is no particular lower limit to the thickness of the film, but in order to prevent tearing due to friction with battery cells and the like and to obtain the desired strength, the thickness is preferably 0.005 mm or more, and more preferably 0.01 mm or more.

[0221] (Other materials contained in the film) In addition, since the film is required to be resistant to the high temperatures of the battery cells 20a, 20b, and 20c, it is preferable that the film has flame retardancy, and specifically, it is preferable that the film contains an inorganic substance or a flame retardant. Other materials contained in the film include inorganic substances such as talc, calcium carbonate, aluminum hydroxide, titanium oxide, vermiculite, zeolite, synthetic silica, zirconia, zircon, barium titanate, zinc oxide, and alumina, and flame retardants such as bromine-based flame retardants, chlorine-based flame retardants, phosphorus-based flame retardants, boron-based flame retardants, silicone-based flame retardants, and nitrogen-containing compounds.

[0222] <Elastic material> The elastic material is an elastic material processed into a sheet shape. As shown in the third and fourth embodiments, when the heat transfer suppressing member has the elastic material 51, a known elastic material can be used as the elastic material constituting the elastic material 51. Specifically, a sheet formed of rubber or a thermoplastic elastomer having elasticity that flexibly deforms in response to deformation of the battery cells 20a, 20b, and 20c can be used.

[0223] The rubber may be either synthetic or natural rubber. Examples of synthetic rubber include styrene-butadiene rubber, butadiene rubber, chloroprene rubber, isoprene rubber, butyl rubber, ethylene propylene rubber, nitrile rubber, silicone rubber, fluororubber, acrylic rubber, urethane rubber, polysulfide rubber, epichlorohydrin rubber, and foamed silicone.

[0224] Examples of the thermoplastic elastomer include polystyrene-based, polyolefin-based, vinyl chloride-based, polyurethane-based, polyester-based, polyamide-based, and polybutadiene-based thermoplastic elastomers. The elastomer may be either porous or non-porous. If the elastomer is porous, the cell structure may be either closed cell type or open cell type.

[0225] (Elastic material size) The thickness of the elastic material is not particularly limited, but in order to effectively obtain the effect of the elastic material, it is preferable that the thickness be 1 mm or more and 10 mm or less.

[0226] [Method of manufacturing heat transfer suppression member] A method for manufacturing a heat-transfer suppressing member according to this embodiment will be described in detail below, particularly with respect to an example in which the heat insulating material 40 of Structural Example 2 shown in FIG. 10 is applied to a heat-transfer suppressing member 210 according to a fourth embodiment.

[0227] <Insulation material manufacturing> For example, binder fibers (not shown) having a core-sheath structure, inorganic particles 4, and inorganic fibers 15 are put into a mixer such as a V-type mixer in a predetermined ratio to prepare a mixture. As described above, it is preferable to use, as the binder fiber, fibers having a core-sheath structure with a core made of a first organic material and a sheath made of a second organic material, in which the melting point of the first organic material is higher than that of the second organic material.

[0228] The mixture is then placed in a mold and pressed with a press or the like, and the resulting molded body is heated to melt the sheath of the binder fiber. The heated molded body is then cooled, and the second organic material constituting the molten sheath and the inorganic particles 4 present around the binder fiber are fused to the core (organic fiber 1), and are also fused to each other in the regions where the binder fibers were in contact with each other. This allows the first insulating material 10a to be formed into a sheet.

[0229] Furthermore, the content of the binder fiber (not shown) having a core-sheath structure, the inorganic particles 4, and the inorganic fibers 15 can be adjusted to a content different from that of the first insulating material, and a second insulating material 10b processed into a sheet shape can be obtained by using the same method as for the first insulating material. In the heat-transfer suppressing member 210 according to the fourth embodiment, the first insulating material 10a and the second insulating material 10b are formed to be thin. The insulating material 40 produced by the above method can be easily made thin and has excellent insulating properties, so that it can be suitably used for the heat-transfer suppressing member 210.

[0230] The manufacturing method of the above-mentioned insulating material is an example of an insulating material containing inorganic fibers 15, but an insulating material not containing inorganic fibers 15 can also be obtained in the same manner as the above-mentioned insulating material 40, and the use of inorganic fibers 15 can be selected arbitrarily.

[0231] When the materials for the heat insulating material are mixed and pressurized and heated, the entangled organic fibers 1 exposed on the surface are heated and formed as a fiber layer 11 on the surface of the heat insulating material 40. The fiber layer 11 thus obtained improves the strength of the heat insulating material 40 and has the effect of mitigating impacts on the surface of the heat insulating material 40.

[0232] <Assembly of laminated body> Thereafter, the elastic material 51 is placed on the main surfaces of the first heat insulating material 10a and the second heat insulating material 10b, and both are fixed. The method for fixing the first heat insulating material 10a, the second heat insulating material 10b, and the elastic material 51 to each other is not particularly limited, and various methods can be used, such as a method of bonding with an adhesive or the like, a method of sewing with thread or the like, a method of clamping and fixing with a fixing jig, a method of covering with a film or the like, a method of covering with a thermocompressive film and then heating to shrink the film and fix it. Note that the elastic material 51 does not necessarily need to be laminated, and as shown in the first and second embodiments, only the heat insulating material may be used.

[0233] <Frame manufacturing> Further, a frame 53 is prepared to surround the outer periphery of the heat insulating material. The frame 53 may be made of, for example, a resin, and may be formed as a single unit or may be prepared by combining a plurality of frame members. When the heat transfer suppressing member according to this embodiment has a partition wall, the frame and the partition wall may be formed as a single unit or may be prepared by combining a plurality of members.

[0234] <Inserting the laminate into the frame> Thereafter, the heat insulating material is fitted and fixed in the frame body 53. The method for fixing the heat insulating material to the frame body 53 is not particularly limited, and the heat insulating material may be fixed using a fixing material such as an adhesive, or a groove or the like may be formed in the frame body 53 and the heat insulating material may be fixed by fitting into the groove.

[0235] <Film application> Thereafter, a film 52 having a size sufficient to completely encase the frame 53, the first and second insulating materials 10a and 10b, and the partition walls 58a and 58b is prepared, and the entire structure is enclosed in the film 52, and the overlapped films 52 are joined. The film 52 may be heat-sealed to the frame 53, or may be coated so as to encase only the first and second insulating materials 10a and 10b. The film 52 need not be disposed.

[0236] The above-mentioned heat insulating material is preferably manufactured by a dry method. When using a dry method, inorganic particles 4 suitable for the dry method are used, and a solvent such as water, which is necessary when forming by a wet method, is not added to the above mixture. However, in order to prevent powder such as inorganic particles 4 from flying around during the manufacture of the heat insulating material and making it difficult to handle the raw material, a small amount of solvent such as water can be added within the range of the dry method. For example, by adding a small amount of solvent such as water to the mixture, it is possible to suppress the scattering of inorganic particles during the manufacture.

[0237] Next, the binder fiber and heating conditions that are preferably used in the production of the above-mentioned insulating material, as well as other binder materials, will be described.

[0238] <Binder fiber> When using binder fibers 3 with a core-sheath structure as a material for the heat insulating material, there is no particular limitation as long as the melting point of the first organic material constituting the core is higher than the melting point of the second organic material constituting the sheath. The first organic material constituting the core may be at least one selected from polyethylene terephthalate, polypropylene, and nylon. The second organic material constituting the sheath may be at least one selected from polyethylene terephthalate, polyethylene, polypropylene, and nylon.

[0239] If the melting point of the first organic material constituting the core is sufficiently higher than that of the second organic material constituting the shell, the heating temperature setting margin in the heating step can be expanded, and the temperature setting for obtaining a desired structure can be made easier. For example, the melting point of the first organic material is preferably 60° C. or more higher than that of the second organic material, more preferably 70° C. or more higher, and even more preferably 80° C. or more higher.

[0240] Note that binder fibers 3 having the above-mentioned core-sheath structure are generally commercially available, and the materials constituting the core and sheath may be the same or different. Examples of binder fibers in which the core and sheath are made of the same material but have different melting points include those in which the core and sheath are made of polyethylene terephthalate, polypropylene, and nylon. Examples of binder fibers in which the core and sheath are made of different materials include those in which the core is made of polyethylene terephthalate and the sheath is made of polyethylene, and those in which the core is made of polypropylene and the sheath is made of polyethylene.

[0241] In this embodiment, the melting point of the second organic material constituting the sheath of the binder fiber 3 refers to the melting temperature at which the second organic material begins to melt and deform, but softening accompanied by a change in shape is also considered to be a type of melting deformation. The melting point of the sheath of the binder fiber can be measured, for example, by the following method. The binder fiber to be measured is placed in contact with the glass fiber having a higher melting point, heated from room temperature to, for example, 200°C at a heating rate of 5°C / min, and then cooled to room temperature. At this time, if the surface of the binder fiber melts and deforms and is fused at the part in contact with the glass fiber or the cross-sectional shape of the binder fiber changes, it can be determined that the melting point of the second organic material constituting the sheath is 200°C or less. In this embodiment, the heating temperature is changed in various ways, and the fusion state between the binder fiber and the glass fiber or the cross-sectional shape of the binder fiber after cooling is observed by the above-mentioned method, whereby the melting point of the second organic material constituting the sheath can be specified.

[0242] (Binder fiber content) When using binder fiber 3 having a core-sheath structure as a material for an insulating material, if the content of the binder fiber in the mixture is appropriately controlled, the skeleton of the resulting insulating material can be sufficiently reinforced. The content of the binder fibers 3 is preferably 5% by mass or more, and more preferably 10% by mass or more, based on the total mass of the mixture. If the content of the binder fibers 3 is too high, the content of the inorganic particles 4 is relatively reduced, so in order to obtain the desired heat insulating performance, the content of the binder fibers 3 is preferably 25% by mass or less, and more preferably 20% by mass or less, based on the total mass of the mixture.

[0243] (Hot melt powder) In this embodiment, in addition to the binder fibers 3 and inorganic particles 4, the mixture may contain hot melt powder as a binder material. The hot melt powder is a powder that contains, for example, a third organic material different from the first organic material and the second organic material, and has the property of melting when heated. By adding the hot melt powder to the mixture and heating it, the hot melt powder melts, and when cooled, it hardens in a state including the surrounding inorganic particles 4. Therefore, it is possible to further suppress the falling off of the inorganic particles 4 from the heat insulating material.

[0244] There are various types of hot melt powders having various melting points, and a hot melt powder having an appropriate melting point can be selected in consideration of the melting points of the core and sheath of the binder fiber to be used. Specifically, if the third organic material, which is a component constituting the hot melt powder, has a melting point lower than that of the first organic material constituting the organic fiber, the heating temperature can be set to melt the sheath and hot melt powder while leaving the core. For example, if the melting point of the hot melt powder is lower than the melting point of the sheath, the heating temperature during production can be set between the melting points of the core and the sheath, making it even easier to set the heating temperature.

[0245] On the other hand, the type of hot melt powder used can be selected so that the melting point of the hot melt powder is between the melting points of the core and the sheath. When a hot melt powder having such a melting point is used, when the sheath and the hot melt powder are both melted and then cooled and hardened, the organic fiber (core) 1 and the molten sheath around it, and the hot melt powder present in the gaps between the inorganic particles 4 harden first. As a result, the position of the organic fiber 1 can be fixed, and then the molten sheath is welded to the organic fiber, making it easier to form a three-dimensional skeleton. Therefore, the strength of the entire sheet can be further improved.

[0246] If the melting point of the third organic material constituting the hot melt powder is sufficiently lower than that of the first organic material constituting the core, the heating temperature setting margin in the heating step can be expanded, and the temperature setting for obtaining a desired structure can be made easier. For example, the melting point of the first organic material is preferably 60° C. or more higher than the melting point of the third organic material, more preferably 70° C. or more higher, and even more preferably 80° C. or more higher.

[0247] The melting point of the hot melt powder (third organic material) is preferably 80° C. or higher, and more preferably 90° C. or higher. The melting point of the hot melt powder (third organic material) is preferably 180° C. or lower, and more preferably 150° C. or lower. Components constituting the hot melt powder include polyethylene, polyester, polyamide, ethylene vinyl acetate, and the like.

[0248] (Hot melt powder content) When hot melt powder is added to the mixture to suppress the falling off of inorganic particles, the effect of suppressing powder falling can be obtained even with a small amount of hot melt powder. Therefore, the content of hot melt powder is preferably 0.5% by mass or more, more preferably 1% by mass or more, based on the total mass of the mixture. On the other hand, when the content of the hot melt powder is increased, the content of the inorganic particles 4 and the like is relatively decreased, so in order to obtain the desired heat insulating performance, the content of the hot melt powder is preferably 5 mass % or less, and more preferably 4 mass % or less, relative to the total mass of the mixture.

[0249] <Heating conditions> When using binder fibers with a core-sheath structure as the material for the heat insulating material, the heating temperature in the heating step is preferably higher than the melting point of the second organic material constituting the sheath and lower than the melting point of the first organic material constituting the core. By setting the heating temperature in this manner, as described above, the strength of the sheet can be ensured by the core on both the surface side and the center side of the sheet, and the inorganic particles 4 can be held by the fused parts 5.

[0250] Specifically, the heating temperature in the heating step is set preferably 10° C. or more higher, more preferably 20° C. or more higher, than the melting point of the second organic material constituting the sheath, while the heating temperature is set preferably 10° C. or more lower, more preferably 20° C. or more lower, than the melting point of the first organic material constituting the core.

[0251] The heating time is not particularly limited, but it is preferable to set the heating time so that the sheath can be sufficiently melted, for example, from 3 minutes to 15 minutes.

[0252] When the heat insulating material contains hot melt powder, the heating temperature in the heating step is preferably set to be 10°C or more higher than the higher of the melting point of the second organic material constituting the sheath and the melting point of the third organic material constituting the hot melt powder, and more preferably set to be 20°C or more higher. On the other hand, the heating temperature is preferably set to be 10°C or more lower than the melting point of the first organic material constituting the core, and more preferably set to be 20°C or more lower. By setting the heating temperature at such a level, a strong skeleton can be formed, the strength of the sheet can be further improved, and the inorganic particles 4 can be prevented from falling off by the fused parts 5, etc.

[0253] <Insulation thickness> In this embodiment, the thickness of the heat insulating material is not particularly limited, but is preferably the same as or thinner than the thickness of the frame body. Specifically, the thickness of the heat insulating material is preferably 0.05 mm or more and 10 mm or less. If the thickness is 0.05 mm or more, sufficient compressive strength can be obtained. On the other hand, if the thickness is 10 mm or less, good heat insulating properties of the heat transfer suppressing member can be obtained.

[0254] [Battery pack] An example of a battery pack to which the heat-transfer suppressing member 180 according to the first embodiment of the present invention is applied is as shown in FIG. 2. Here, the configuration and effects of the battery pack will be specifically described with reference to FIG. 2. As described above, the heat-transfer suppressing member 180 shown in FIG. 2 can be replaced with heat-transfer suppressing members 181, 182, 190, 200, 210 having other structures, as well as with heat-transfer suppressing members having other structures within the scope of the present invention. In addition, as for the heat insulating material, in addition to the heat insulating material 10, the first heat insulating material 10a, the second heat insulating material 10b, the heat insulating materials 40, 60, 70, 80, 90, 110 having the various structures described above, it can also be replaced with other heat insulating materials within the scope of the present invention.

[0255] 2, the battery pack 100 includes a plurality of battery cells 20a, 20b, and 20c, and a heat transfer suppressing member 180 according to the present embodiment, and the plurality of battery cells are connected in series or in parallel. For example, the heat transfer suppressing member 180 according to the present embodiment is interposed between the battery cells 20a and 20b, and between the battery cells 20b and 20c. Furthermore, the battery cells 20a, 20b, and 20c and the heat transfer suppressing member 180 are housed in a battery case 30. The heat transfer suppressing member 180 is as described above.

[0256] In the battery pack 100 configured in this manner, the heat transfer suppression member has the frame 53, so that the spacing between the battery cells can be secured. Furthermore, since there is no frame in the area that becomes hot in the event of an abnormality, and the insulation material extends to the end faces, even if an abnormality occurs in some of the battery cells and part of the frame 53 is burned, deterioration of insulation properties can be suppressed. Therefore, destruction of the battery case and deterioration of battery performance can be suppressed, and heat propagation between the battery cells in the event of an abnormality can be suppressed.

[0257] Furthermore, when the battery cells 20a, 20b, and 20c have exhaust valves (not shown), it is preferable that a heat transfer suppression member is interposed between the battery cells so that the exposed end faces of the insulating material and the faces of the battery cells 20a, 20b, and 20c on which the exhaust valves are arranged face in the same direction. Since there is no frame on the exposed end faces of the insulating material, even if an abnormality occurs in a battery cell, a decrease in insulation performance due to the frame being burned can be suppressed.

[0258] Furthermore, it is preferable that the frame body has a pair of frame members arranged approximately parallel to each other, and when the pair of frame members are connected to each other by one or more partition walls, the heat transfer suppressing member is interposed between the multiple battery cells so that the pair of frame members are approximately parallel in the vertical direction. If the heat transfer suppressing member is arranged so that the pair of frame members are approximately parallel in the vertical direction, the frame member is not required on the upper end surface of the heat transfer suppressing member, so that even if an abnormality occurs in a battery cell, a decrease in thermal insulation due to the frame body being burned can be suppressed. In addition, when the frame bodies are "approximately parallel" to each other, it is acceptable for the angle between two straight lines, one on each of the main surfaces of the frame bodies, to be 5° or less, preferably 3° or less, and more preferably 1° or less. In addition, when a pair of frame members are "approximately parallel" to each other, it is acceptable for the angle between two straight lines, one on each of the main surfaces of the frame members, to be 5° or less, preferably 3° or less, and more preferably 1° or less.

[0259] The battery pack 100 of this embodiment is not limited to the battery pack illustrated in Fig. 2. For example, the heat transfer suppressing member 180 may be disposed not only between the battery cells 20a and 20b and between the battery cells 20b and 20c, but also between the battery cells 20a, 20b, and 20c and the battery case 30, or may be attached to the inner surface of the battery case 30.

[0260] In the battery pack 100 configured in this manner, if a battery cell catches fire, it is possible to prevent the flame from spreading outside the battery case 30. For example, the battery pack 100 according to this embodiment may be used in an electric vehicle (EV) or the like, and may be placed under the floor of a passenger compartment. In this case, even if a battery cell catches fire, the safety of the passengers can be ensured. Furthermore, since the heat transfer suppression member 180 can be disposed not only between each battery cell but also between the battery cells 20a, 20b, 20c and the battery case 30, there is no need to fabricate new flame retardant materials, etc., and a safe battery pack 100 can be easily constructed at low cost.

[0261] The heat transfer suppressing member according to this embodiment can be manufactured into various shapes depending on the manufacturing method. Therefore, it can be adapted to any shape without being affected by the shapes of the battery cells 20a, 20b, 20c and the battery case 30. Specifically, in addition to prismatic batteries, it can also be applied to cylindrical batteries, flat batteries, etc. [Explanation of symbols]

[0262] 1. Organic Fibers 4 Inorganic particles 54 Cavity 10,40,60,70,80,90,110 Insulation 10a First insulation material 10b Second insulation material 10e end face 20a, 20b, 20c Battery cells 30 Battery case 51 Elastic material 52 Film 53 Frame 53a, 53b Frame members 53e Outer end surface 58a,58b Partition wall 100 battery packs 111 Laminate 111s Outer main surface 180,181,182,190,200,210 Heat transfer suppression material

Claims

1. A frame body that constitutes a part of the outer periphery in a plan view; A plate-shaped insulating material having a pair of main surfaces and end surfaces substantially perpendicular to the main surfaces, The frame has an outer end surface parallel to the end surface of the thermal insulation material, A heat transfer suppression member characterized in that at least a portion of the insulation material is arranged inside the frame body so that the end face of the insulation material exposed in the area of ​​the outer periphery where the frame body is not present is approximately flush in a plan view with at least a portion of the outer end face of the frame body, or protrudes from at least a portion of the outer end face of the frame body.

2. The frame body has a pair of frame members arranged substantially parallel to each other, The pair of frame members are connected to each other by one or more partition walls, and the inside of the frame body is divided into a plurality of regions by the partition walls, The heat transfer suppressing member according to claim 1 , further comprising a plurality of the heat insulating materials arranged in each of the plurality of regions.

3. The heat transfer suppressing member according to claim 2 , wherein the plurality of heat insulating materials include a first heat insulating material and a second heat insulating material having properties different from each other.

4. The heat transfer suppressing member according to claim 3 , wherein the first insulating material has a modulus of elasticity smaller than a modulus of elasticity of the second insulating material.

5. The heat transfer suppressing member according to claim 4 , wherein the first insulating material is disposed in a region that is located at a center of the plurality of regions.

6. The heat transfer suppressing member according to claim 2 , further comprising a film covering the main surfaces and the exposed end faces of the plurality of heat insulating materials.

7. The heat transfer suppressing member according to claim 2 , wherein in a cross-sectional view perpendicular to the plan view, a thickness of at least one of the plurality of heat insulating materials is thinner than a thickness of the frame body.

8. The heat transfer suppressing member according to claim 7 , further comprising a film covering the main surfaces and the exposed end faces of the plurality of heat insulating materials.

9. The heat transfer suppressing member according to claim 8 , further comprising a gap between a main surface of the heat insulating material and the film.

10. The heat transfer suppressing member according to claim 7 , wherein an elastic material is laminated on at least one of the main surfaces of at least one of the plurality of heat insulating materials.

11. The heat transfer suppressing member according to claim 10, wherein the elastic material includes at least one material selected from the group consisting of synthetic rubber, natural rubber, and thermoplastic elastomer.

12. The heat transfer suppressing member according to claim 10 , further comprising a film covering at least a part of an outer main surface of the laminate of the heat insulating material and the elastic material.

13. The heat transfer suppressing member according to claim 12, further comprising a gap between the laminate and the film.

14. The heat transfer suppressing member according to claim 2 , wherein, in a plan view, a width of the partition wall in a direction perpendicular to the longitudinal direction is smaller than a width of the frame in the direction perpendicular to the longitudinal direction.

15. The heat transfer suppressing member according to any one of claims 2 to 14, wherein the partition wall is made mainly of an insulating material.

16. The heat transfer suppressing member according to any one of claims 1 to 14, wherein the frame body is made mainly of an insulating material.

17. The heat transfer suppressing member according to any one of claims 1 to 14, wherein the heat insulating material contains inorganic particles and organic fibers.

18. 15. A battery pack comprising: a plurality of battery cells; and the heat transfer suppressing member according to claim 1, the plurality of battery cells being connected in series or in parallel.

19. The plurality of battery cells have exhaust valves, the heat transfer suppressing member is interposed between the plurality of battery cells, 19. The battery pack according to claim 18, wherein the heat transfer suppression member is arranged so that the exposed end face of the insulating material and a face of the battery cell on which the exhaust valve is arranged are oriented in the same direction.

20. A heat transfer suppressing member according to any one of claims 2 to 14, comprising a plurality of battery cells connected in series or parallel, the heat transfer suppressing member is interposed between the plurality of battery cells, the heat transfer suppressing member is disposed so that the pair of frame members are substantially parallel to each other in a vertical direction.

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