Battery device

Abstract

The present invention provides a battery device that can suppress the overheating of the case due to the effects of substances emitted from the battery cells. [Solution] The battery comprises a plurality of battery cells 52, each having a cell case 53 equipped with a release valve 54 that opens when the internal pressure reaches a predetermined value; a case 35 for housing the plurality of battery cells; non-combustible paper 44 provided on at least a part of the inner surface of the case; an intermediate material 46 provided on the side of the non-combustible paper opposite to the inner surface of the case and having higher mechanical strength than the non-combustible paper; and an insulating plate 48A provided on the side of the intermediate material opposite to the non-combustible paper, facing the release valve and having higher electrical insulation properties and higher mechanical strength than the non-combustible paper, wherein the heat insulation properties of the non-combustible paper and intermediate material are higher than those of the insulating plate.

Description

Technical Field

[0001] The present invention relates to a battery device.

Background Art

[0002] Patent Document 1 below discloses a battery device in which a plurality of battery cells are provided inside a case. The case includes a metal lower case and a resin upper case. A steel plate facing a release valve provided on the upper part of each battery cell is fixed to the ceiling part of the inner surface of the upper case.

[0003] When the internal pressure of any one of the battery cells rises, the release valve opens, and the high-temperature gas is vigorously discharged from the release valve to the outside of the battery cell and collides with the steel plate. Therefore, the steel plate suppresses the upper case from being heated by the high-temperature gas discharged from the battery cell.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In Patent Document 1 above, when the steel plate falls from the upper case due to the influence of gas, the upper case may be heated. Thus, Patent Document 1 has room for improvement in suppressing the case from being heated by the influence of the high-temperature substance discharged from the battery cell.

[0006] In consideration of the above facts, an object of the present invention is to obtain a battery device capable of suppressing the case from being heated by the influence of the substance discharged from the battery cell.

Means for Solving the Problems

[0007] The battery device of the first embodiment comprises a plurality of battery cells, each having a cell case equipped with a release valve that opens when the internal pressure reaches a predetermined value; a case for housing the plurality of battery cells; non-combustible paper provided on at least a portion of the inner surface of the case; an intermediate material provided on the surface of the non-combustible paper opposite to the inner surface and having higher mechanical strength than the non-combustible paper; and an insulating plate provided on the surface of the intermediate material opposite to the non-combustible paper, facing the release valve and having electrical insulation properties and higher mechanical strength than the non-combustible paper, wherein the thermal insulation properties of the non-combustible paper and the intermediate material are higher than those of the insulating plate.

[0008] In the battery device of the first embodiment, when the internal pressure of the battery cell reaches a predetermined value, the release valve opens, and the substance inside the battery cell is discharged to the outside of the cell case through the release valve. As a result, the high-temperature substance may collide forcefully with the insulating plate facing the release valve. However, the mechanical strength of the insulating plate and the intermediate material located between the insulating plate and the non-combustible paper is higher than that of the non-combustible paper. Therefore, even if the substance collides forcefully with the insulating plate, there is little risk of the non-combustible paper peeling off from the inner surface of the case. Thus, the non-combustible paper can suppress the transfer of heat from the substance to the case.

[0009] Furthermore, if the insulating plate of the battery device in the first embodiment detaches from the case, the insulating plate may simultaneously come into contact with the terminals of two adjacent battery cells. However, since the insulating plate has electrical insulating properties, a short circuit will not occur between the two adjacent battery cells via the insulating plate. Therefore, there is little risk of the battery cells overheating due to a short circuit.

[0010] In this way, when material is discharged from the battery cells, the heat from this material is less likely to be transferred to the case, and a short circuit does not occur between two adjacent battery cells via the insulating plate. Therefore, the battery device of the first embodiment can suppress the case from becoming hot due to the influence of material discharged from the battery cells.

[0011] In the second embodiment of the battery device, the case is made of an iron-containing material, and the inner surface of the case is coated with a cationic coating.

[0012] Although the case of the battery device in the second embodiment is made of an iron-containing material, the case surface is coated with a cationic coating, making it resistant to rust. Furthermore, the cationic coated parts are prone to self-ignition when heated to high temperatures. However, since the case does not easily become hot, the risk of self-ignition of the cationic coated parts when high-temperature substances are discharged from the battery cells is small.

[0013] In the third embodiment of the battery device, in the first or second embodiment, the area of ​​the non-combustible paper and the intermediate material when viewed in the thickness direction of the non-combustible paper is larger than the area of ​​the insulating plate.

[0014] In the battery device of the third embodiment, the discharge range of gas from the battery cell tends to be wider than the discharge range of substance that collides forcefully with the insulating plate. However, since the area of ​​the non-combustible paper and intermediate material when viewed in the thickness direction of the non-combustible paper is larger than the area of ​​the insulating plate, the non-combustible paper and intermediate material can suppress the overheating of the case by high-temperature gas discharged over a wider area than the substance that collides forcefully with the insulating plate.

[0015] In the fourth embodiment of the battery device, the intermediate material is glass cloth in any of the first to third embodiments.

[0016] In the battery device of the fourth embodiment, the intermediate material is glass cloth. Therefore, it is easy to manufacture an intermediate material at low cost that has higher mechanical strength than non-combustible paper and higher thermal insulation properties than insulating plates.

[0017] In the fifth embodiment of the battery device, the insulating plate is a mica plate in any of the first to fourth embodiments.

[0018] In the battery device of the fifth embodiment, the insulating plate is a mica plate. Therefore, the insulating plate of the fifth embodiment has high electrical insulation and mechanical strength.

[0019] The sixth type of battery device, in any of the first to fifth embodiments, comprises a case comprising a lower case and an upper case which is integrated with the lower case and together constitutes the case, the release valve is provided on the upper surface of the cell case, and the non-combustible paper is provided on the ceiling portion of the inner surface of the upper case.

[0020] In the battery device of the sixth embodiment, the substance inside the battery cell is discharged upwards through a release valve provided on the top surface of the cell case, and this substance may forcefully collide with an insulating plate provided on the ceiling of the inner surface of the upper case. In this case, the insulating plate may detach from the upper case and come into contact with the terminals of two adjacent battery cells simultaneously. However, since the insulating plate has electrical insulating properties, a short circuit will not occur between two adjacent battery cells via the insulating plate.

[0021] The seventh embodiment of the battery device is provided in any of the first to sixth embodiments, in which a battery stack having a plurality of the battery cells arranged in a predetermined linear direction in a plan view is provided in the case, the insulating plate is a plate material extending along the linear direction, and a single insulating plate faces the release valve of the plurality of battery cells.

[0022] In the battery device of the seventh embodiment, a single insulating plate faces the release valves of multiple battery cells. Therefore, the battery device of the seventh embodiment can have fewer parts.

[0023] In the battery device according to the eighth aspect, in the seventh aspect, in a plan view, the plurality of battery stacks are arranged while forming a gap in a direction orthogonal to the linear direction, and the two insulating plates face each of the plurality of battery cells arranged in the linear direction, and the two insulating plates are provided on a single intermediate member that overlaps with the gap when viewed in the thickness direction of the non-combustible paper.

[0024] In the battery device according to the eighth aspect, the number of components can be reduced as compared with the case where two intermediate members are provided in the case so as not to overlap with the gap formed between two adjacent battery stacks.

[0025] In the battery device according to the ninth aspect, in the eighth aspect, when a single intermediate member is provided on a single non-combustible paper and a direction orthogonal to the linear direction when viewed in the thickness direction of the non-combustible paper is defined as an orthogonal direction, one end portion of the non-combustible paper and the intermediate member on one side in the orthogonal direction is located on the one side with respect to the two insulating plates, and the other end portion of the non-combustible paper and the intermediate member on the other side in the orthogonal direction is located on the other side with respect to the two insulating plates.

[0026] In the battery device according to the ninth aspect, it is possible to suppress a wide area of the case from being heated to a high temperature by high-temperature gas discharged from the battery cell by a single non-combustible paper and a single intermediate member.

[0027] The battery device according to the tenth aspect is mounted on an electric vehicle in any one of the first aspect to the ninth aspect.

[0028] The battery device according to the tenth aspect can suppress the case of the battery device mounted on the electric vehicle from being heated to a high temperature due to the influence of substances discharged from the battery cell.

Advantages of the Invention

[0029] As described above, the battery device according to the present invention has an excellent effect of suppressing the case from being heated to a high temperature due to the influence of substances discharged from the battery cell.

Brief Description of the Drawings

[0030] [Figure 1] This is a schematic plan view showing a battery device according to an embodiment, and a part of the body frame member of an electric vehicle equipped with the battery device. [Figure 2] This is a schematic cross-sectional view along the arrow 2-2 in Figure 1. [Figure 3] This is a schematic exploded perspective view of the battery unit. [Figure 4] This is a schematic perspective view of the upper case and cover unit, which are separated from each other. [Figure 5] This is a schematic exploded perspective view of the cover unit. [Figure 6] This is a schematic bottom view of the upper case and cover unit. [Figure 7] This is a schematic cross-sectional view of the top panel, cover unit, and battery stack of the upper case. [Figure 8] This is a schematic perspective view of a battery cell. [Figure 9] This is a schematic plan view of the lower case and battery stack. [Figure 10] This is a cross-sectional view similar to Figure 7, showing the mica plate detached from the top panel of the upper case. [Modes for carrying out the invention]

[0031] The battery device according to the embodiment will be described below with reference to the attached drawings. Note that the arrows UP, FR, and LH in each figure indicate the upper side in the vertical direction of the vehicle, the front side in the longitudinal direction (orthogonal direction) of the vehicle, and the left side in the lateral direction (straight direction) of the vehicle, respectively.

[0032] As shown in Figures 1 and 2, the battery device 20 of this embodiment is mounted on a vehicle (electric vehicle) 10. The vehicle 10 of this embodiment is an electric vehicle (BEV: Battery Electric Vehicle).

[0033] The vehicle 10 comprises a pair of left and right front wheels 11F, a pair of left and right rear wheels 11R, a pair of left and right rockers 12 which are part of the vehicle body frame and extend in the longitudinal direction of the vehicle, and a pair of front and rear cross members 14 which are part of the vehicle body frame and extend in the vehicle width direction (left and right direction), with both ends fixed to the left and right rockers 12.

[0034] The battery device 20 of this embodiment includes a battery case 22 and a battery stack 50. Power from the battery device 20 (battery cells 52) is supplied, for example, to an electric motor (not shown) that provides driving force to the front wheel 11F and the rear wheel 11R.

[0035] As shown in Figures 2 and 3, the battery case 22 has a lower case 24 and an upper case 35. The lower case 24 and the upper case 35 are integrally molded metal parts containing iron. Furthermore, the entire surface of the lower case 24 is coated with cationic coating 24A, and the entire surface of the upper case 35 is coated with cationic coating 35A.

[0036] The lower case 24 is a hollow body with an opening 25 formed on its upper surface. The lower case 24 has a bottom plate portion 26, a peripheral wall portion 27, and an outer peripheral flange 28. The peripheral wall portion 27 has an annular planar shape, and its lower end is connected to the outer peripheral edge of the bottom plate portion 26. The outer peripheral flange 28 has an annular planar shape, and its inner peripheral edge is connected to the upper end of the peripheral wall portion 27.

[0037] The upper case 35 is a hollow body with an opening 36 formed on its lower surface. The upper case 35 has a top plate portion 37, a peripheral wall portion 38, and an outer peripheral flange 39. The peripheral wall portion 38 has an annular planar shape, and its upper end is connected to the outer peripheral edge of the top plate portion 37. The outer peripheral flange 39 has an annular planar shape, and its inner peripheral edge is connected to the lower end of the peripheral wall portion 38.

[0038] As shown in Figure 4, four cover units 42-1, 42-2, 42-3, and 42-4 are fixed to the inner surface (bottom surface) of the top plate 37 of the upper case 35. Note that when it is not necessary to distinguish between the individual cover units, cover units 42-1, 42-2, 42-3, and 42-4 may be collectively referred to as cover unit 42. As shown in Figure 5, the cover unit 42 comprises non-combustible paper 44, glass cloth (intermediate material) 46 with a planar shape substantially identical to that of the non-combustible paper 44, and two mica plates (insulating plates) 48. The planar shape of the non-combustible paper 44 is a rectangle whose left-to-right dimension is longer than its front-to-back dimension. The planar shape of the glass cloth 46 is substantially identical to that of the non-combustible paper 44. The planar shape of the mica plate 48 is a rectangle whose left-to-right dimension is substantially the same as that of the non-combustible paper 44 and whose front-to-back dimension is shorter than that of the non-combustible paper 44. That is, the mica plate 48 is a plate material that extends along the left-to-right direction. As shown in Figure 4, the left-right dimensions of the non-combustible paper 44, glass cloth 46, and mica plate 48 are shorter than half the left-right dimensions of the top plate 37. The front-to-back dimensions of the non-combustible paper 44 and glass cloth 46 are shorter than half the front-to-back dimensions of the top plate 37.

[0039] The non-combustible paper 44 is an inorganic paper whose main component is, for example, magnesium silicate, a natural mineral that is non-asbestos. The non-combustible paper 44 has excellent heat insulation properties. In other words, the heat insulation properties of the non-combustible paper 44 are higher than those of the upper case 35, glass cloth 46, and mica plate 48. Furthermore, the non-combustible paper 44 has insulating properties. As the non-combustible paper 44, for example, M-thermo insulation material (I-30F) from Awa Paper Co., Ltd. can be used. This M-thermo insulation material (I-30F) has high heat resistance (600℃).

[0040] Glass cloth 46 is a woven fabric made using glass yarn. Glass cloth 46 has excellent mechanical strength. In other words, the mechanical strength of glass cloth 46 is higher than that of non-combustible paper 44. Furthermore, the thermal insulation properties of glass cloth 46 are higher than those of mica plate 48.

[0041] The mica plate 48 is a sheet material made of mica. As is well known, mica has excellent electrical insulation and heat resistance. The electrical insulation of the mica plate 48 is higher than that of the non-combustible paper 44 and the glass cloth 46. Furthermore, the mica plate 48 has excellent mechanical strength. In other words, the mechanical strength of the mica plate 48 is higher than that of the non-combustible paper 44 and the glass cloth 46.

[0042] As shown in Figures 4, 6, and 7, the upper surface of the glass cloth 46 is fixed to the lower surface of the non-combustible paper 44 using heat-resistant double-sided tape (not shown). In a plan view, the outer edges of the non-combustible paper 44 and the outer edges of the glass cloth 46 overlap each other in the vertical direction. Furthermore, the upper surfaces of two mica plates 48 are fixed to the lower surface of the glass cloth 46 using multiple heat-resistant double-sided tapes (not shown). In a plan view, the left edge of the glass cloth 46 and the left edges of the two mica plates 48 overlap in the vertical direction, and the right edge of the glass cloth 46 and the right edges of the two mica plates 48 overlap in the vertical direction.

[0043] As shown in Figures 4 and 6, in the following description, the two mica plates 48 provided on the glass cloth 46 of cover unit 42-1 may be referred to as mica plate 48A and 48B, respectively. Mica plate 48B is located behind mica plate 48A. The front edge of the non-combustible paper 44 and glass cloth 46 of cover unit 42-1 is located in front of the front edge of mica plate 48A, and the rear edge of the non-combustible paper 44 and glass cloth 46 of cover unit 42-1 is located behind the rear edge of mica plate 48B. In addition, the two mica plates 48 provided on the glass cloth 46 of cover unit 42-2 may be referred to as mica plate 48C and 48D, respectively. Mica plate 48D is located behind mica plate 48C. The front edges of the non-combustible paper 44 and glass cloth 46 of cover unit 42-2 are located in front of the front edge of mica plate 48C, and the rear edges of the non-combustible paper 44 and glass cloth 46 of cover unit 42-2 are located behind the rear edge of mica plate 48D. The two mica plates 48 provided on the glass cloth 46 of cover unit 42-3 may be referred to as mica plate 48E and 48F, respectively. Mica plate 48F is located behind mica plate 48E. The front edges of the non-combustible paper 44 and glass cloth 46 of cover unit 42-3 are located in front of the front edge of mica plate 48E, and the rear edges of the non-combustible paper 44 and glass cloth 46 of cover unit 42-3 are located behind the rear edge of mica plate 48F. The two mica plates 48 provided on the glass cloth 46 of cover unit 42-4 may be referred to as mica plate 48G and 48H, respectively. The mica plate 48H is located behind the mica plate 48G. The front edge of the non-combustible paper 44 and glass cloth 46 of the cover unit 42-4 is located in front of the front edge of the mica plate 48G, and the rear edge of the non-combustible paper 44 and glass cloth 46 of the cover unit 42-4 is located behind the rear edge of the mica plate 48H.

[0044] Furthermore, as shown in Figures 6 and 7, the top surfaces of the non-combustible paper 44 of the four cover units 42-1, 42-2, 42-3, and 42-4 are fixed to the inner surface (bottom surface) of the top plate portion 37 of the upper case 35 using heat-resistant double-sided tape (not shown). More specifically, cover unit 42-1 is fixed to the left half of the front part of the top plate portion 37, cover unit 42-2 is fixed to the right half of the front part of the top plate portion 37, cover unit 42-3 is fixed to the left half of the rear part of the top plate portion 37, and cover unit 42-4 is fixed to the right half of the rear part of the top plate portion 37. As shown in Figure 6, a gap GP1 is formed between the right edge of cover unit 42-1 and the left edge of cover unit 42-2, and a gap GP1 is formed between the right edge of cover unit 42-3 and the left edge of cover unit 42-4. Furthermore, a gap GP2 is formed between the rear edge of cover unit 42-1 and the front edge of cover unit 42-3, and a gap GP2 is also formed between the rear edge of cover unit 42-2 and the front edge of cover unit 42-4.

[0045] As shown in Figure 3, eight battery stacks 50A, 50B, 50C, 50D, 50E, 50F, 50G, and 50H are provided inside the lower case 24. Each battery stack 50A, 50B, 50C, 50D, 50E, 50F, 50G, and 50H comprises multiple battery cells 52 arranged in the left-right direction, numerous busbars (not shown), and a cooler (not shown). Note that when it is not necessary to distinguish between the battery stacks, the battery stacks 50A, 50B, 50C, 50D, 50E, 50F, 50G, and 50H may be collectively referred to as battery stack 50. As shown in Figure 8, a release valve 54 and a pair of external electrodes 56 are provided on the upper surface of the metal cell case 53 that constitutes the outer shape of the lithium-ion battery cell 52. One external electrode 56 is the positive electrode, and the other external electrode 56 is the negative electrode. The release valve 54 opens when the pressure in the internal space of the battery cell 52 reaches a predetermined pressure, and discharges the contents housed in the internal space of the cell case 53 to the outside. In this embodiment, the release valve 54 is separate from the cell case 53 and is movable relative to the cell case 53. However, the release valve 54 may be a weak point formed in the cell case 53. A weak point is, for example, a part of the cell case 53 that is thinner than the surrounding area.

[0046] As shown in Figure 9, the battery stacks 50A, 50B, 50C, 50D, 50E, 50F, 50G, and 50H are housed inside the lower case 24. More specifically, the lower surfaces of battery stacks 50A and 50B are fixed to the left half of the front part of the bottom plate 26 of the lower case 24, the lower surfaces of battery stacks 50C and 50D are fixed to the right half of the front part of the bottom plate 26, the lower surfaces of battery stacks 50E and 50F are fixed to the left half of the rear part of the bottom plate 26, and the lower surfaces of battery stacks 50G and 50H are fixed to the right half of the rear part of the bottom plate 26. Gaps GP3 are formed between battery stacks 50A and 50B, between battery stacks 50C and 50D, between battery stacks 50E and 50F, and between battery stacks 50G and 50H. Furthermore, gaps GP4 are formed between battery stack 50A and battery stack 50C, between battery stack 50B and battery stack 50D, between battery stack 50E and battery stack 50G, and between battery stack 50F and battery stack 50H.

[0047] A sealing material (not shown) is provided over the entire upper surface of the outer flange 28 of the lower case 24, which houses each battery stack 50, and the outer flange 39 of the upper case 35 rests on the upper surface of the outer flange 28 and the sealing material. Furthermore, multiple points on the outer flange 28 and outer flange 39 are fixed together by multiple fixing members. These fixing members are, for example, bolts that pass through the outer flange 28 and outer flange 39 and nuts that can be screwed onto the bolts. This completes the battery device 20.

[0048] When the battery device 20 is completed, as shown in Figure 9, the mica plates 48A, 48B, 48C, 48D, 48E, 48F, 48G, and 48H face the release valves 54 of the battery stacks 50A, 50B, 50C, 50D, 50E, 50F, 50G, and 50H from directly above. As shown in Figure 7, a gap is formed between each release valve 54 and each mica plate 48.

[0049] In this configuration, the battery case 22 of the battery device 20 is supported by the rockers 12 and the cross members 14. That is, as shown in Figures 1 and 2, with the top plate portion 37 and peripheral wall portion 38 of the upper case 35 located in the space enclosed by the rockers 12 and the cross members 14, the outer peripheral flange 39 is brought into contact with the lower surface of each rocker 12 and each cross member 14 from below. Furthermore, the lower surface of the rocker 12 and multiple points on the outer peripheral flanges 28 and 39 are fixed together by multiple fixing members. These fixing members are, for example, the bottom plate of the rocker 12, bolts that pass through the outer peripheral flanges 28 and 39, and weld nuts that can be screwed into the bolts and are fixed to the upper surface of the bottom plate of the rocker 12.

[0050] The upper surface of the top plate portion 37 of the upper case 35 constitutes the floor panel of the vehicle 10. A cloth-like mat material (not shown) is placed over the upper surface of the top plate portion 37.

[0051] (Mechanism of action and effect) Next, the operation and effects of the embodiment will be described.

[0052] For example, if a short circuit occurs in any of the battery cells 52 of the battery device 20, the internal pressure of this battery cell 52 will rise. When the internal pressure of this battery cell 52 reaches a predetermined value, the release valve 54 opens, and the high-temperature internal components located inside the battery cell 52 are forcefully discharged upwards to the cell case 53 via the release valve 54. These internal components include, for example, internal electrodes 55 (current collector terminals) (see Figure 7), electrolyte, and gas. The internal electrodes 55 are electrically connected to an electrode body (not shown) located inside the cell case 53 and an external electrode 56 (see Figure 8) located on the upper surface of the cell case 53.

[0053] For example, when a hot internal component is forcefully discharged upward from the release valve 54 of one battery cell 52 in the battery stack 50A, as shown in Figure 7, the internal electrode 55, which is hot and heavier than other internal components (e.g., gas GS), will forcefully collide with the mica plate 48A of the cover unit 42-1 located directly above the release valve 54. However, the mechanical strength of the mica plate 48A and glass cloth 46 of the cover unit 42-1 is higher than that of the non-combustible paper 44. That is, the mechanical strength of the mica plate 48A and glass cloth 46 is high, and the mechanical strength of the mica plate 48A is particularly high. Therefore, even if the internal electrode 55 forcefully collides with the mica plate 48A, there is little risk of the non-combustible paper 44 of the cover unit 42-1 peeling off from the inner surface of the top plate portion 37 of the upper case 35. Thus, the non-combustible paper 44 and glass cloth 46 can suppress the transfer of heat from the hot internal electrode 55 discharged upward from the battery cell 52 to the upper case 35. Therefore, the battery device 20 can suppress the overheating of the battery case 22 due to the influence of high-temperature internal components discharged from the battery cells 52. Consequently, the floor panel, which is the top plate portion 37 of the upper case 35, is less likely to become hot.

[0054] Furthermore, heavier internal components (e.g., internal electrode 55) tend to have a narrower diffusion range after being discharged from the release valve 54 than lighter internal components (e.g., gas GS). Therefore, there is less risk of the heavy internal component, the internal electrode 55, colliding forcefully with the glass cloth 46.

[0055] Furthermore, according to the inventor's experiments, if the cover unit 42 is equipped only with non-combustible paper 44, there is a high risk that the non-combustible paper 44 will peel off the top plate portion 37 when a high-temperature internal component collides forcefully with the non-combustible paper 44. Also, if the cover unit 42 is equipped only with non-combustible paper 44 and glass cloth 46, or if the cover unit 42 is equipped only with non-combustible paper 44 and mica plates 48A and 48B, there is a high risk that the non-combustible paper 44 will peel off the top plate portion 37 when an internal component collides forcefully with the cover unit 42.

[0056] Furthermore, if the internal components of the battery cell 52 collide forcefully with the mica plate 48, the cover unit 42 may detach downward from the top plate portion 37, as shown in Figure 10. In this case, the mica plate 48 may come into contact with the external electrodes 56 provided on the upper surface of the cell case 53 of multiple battery cells 52 located directly below it (only one battery cell 52 is shown in Figure 10). That is, there is a risk that the mica plate 48 may simultaneously come into contact with the external electrodes 56 of multiple battery cells 52 whose release valves 54 are not open. However, since the mica plate 48 has electrical insulating properties, a short circuit will not occur between two adjacent battery cells 52 via the mica plate 48. Therefore, there is little risk of a battery cell 52 whose release valve 54 is not open becoming overheated due to the mica plate 48.

[0057] In this way, by combining the non-combustible paper 44, glass cloth 46, and mica plate 48A, which have different properties from each other, a cover unit 42 is constructed that has excellent heat insulation, mechanical strength, and electrical insulation properties. Furthermore, since this cover unit 42 is provided on the top plate portion 37 of the upper case 35 so as to face the battery cell 52 (release valve 54), the battery device 20 can exhibit the above-mentioned effects.

[0058] Furthermore, since the battery unit 20 is installed in the vehicle 10, the lower case 24 and upper case 35 are prone to moisture such as rain. Although the lower case 24 and upper case 35 are made of metal material containing iron, the entire surface of the lower case 24 and upper case 35 is coated with cationic paint 24A and 35A. Therefore, although moisture is prone to adhering to the surface of the lower case 24 and upper case 35, the lower case 24 and upper case 35 are resistant to rust.

[0059] Furthermore, the cation-coated portion of the battery case 22 is prone to self-ignition when heated. However, as mentioned above, if hot internal components are discharged from the release valve 54 of any of the battery cells 52 toward the top plate portion 37, the top plate portion 37 is unlikely to become hot. Therefore, there is little risk of the top plate portion 37 of the upper case 35 self-igniting due to hot internal components discharged upward from the release valve 54.

[0060] Furthermore, as shown in Figure 7, the discharge range of the high-temperature gas GS, which is contained in the internal components and is lighter than the internal electrodes 55, tends to be wider than the discharge range of the internal electrodes 55 discharged from the battery cell 52 and forcefully colliding with the mica plate 48A. However, the area of ​​the non-combustible paper 44 and glass cloth 46 when viewed in the thickness direction (vertical direction) of the non-combustible paper 44 is larger than the area of ​​the mica plate 48A. Therefore, the non-combustible paper 44 and glass cloth 46 can suppress the heating of the top plate portion 37 by the high-temperature gas GS discharged from the release valve 54 over a wide area. Moreover, even if the gas GS forcefully contacts the mica plate 48A or glass cloth 46, there is little risk of the non-combustible paper 44 peeling off from the inner surface of the top plate portion 37.

[0061] Furthermore, each cover unit 42 has a single mica plate 48 that faces vertically the release valve 54 of each battery cell 52 located directly below it in the battery stack 50. As a result, the battery device 20 has fewer parts compared to a case where each cover unit 42 has the same number of mica plates as the release valve 54 of each battery cell 52 located directly below it in the battery stack 50.

[0062] Furthermore, as shown in Figures 6 and 9, the non-combustible paper 44 and glass cloth 46 of each cover unit 42 have a portion 42P located directly above the gap GP3 formed between two battery stacks 50 that are located directly below and aligned in the front-to-back direction. That is, when the battery device 20 is viewed along the vertical direction, the gap GP3 and a portion (portion 42P) of the single non-combustible paper 44 and glass cloth 46 overlap. In a plan view, each of these portions 42P is located away from the release valve 54 of the battery cell 52 of the battery stack 50 in the front-to-back direction. Therefore, there is little risk of the hot internal components discharged from the release valve 54 of the battery cell 52 coming into contact with each of these portions 42P. For this reason, it is also possible to separate each cover unit 42 into two portions located in front of and behind portion 42P. However, in this case, eight cover units would need to be provided on the top plate portion 37, which would increase the number of parts in the battery device 20. In contrast, in the case of the battery device 20 of this embodiment, where each cover unit 42 has a part 42P, the number of cover units 42 provided on the top plate 37 becomes four. Therefore, the battery device 20 can have fewer parts compared to the case where each cover unit 42 does not have a part 42P. As a result, the assembly of the battery device 20 is easier compared to the case where each cover unit 42 does not have a part 42P.

[0063] Although battery devices according to each embodiment have been described above, these can be modified as appropriate without departing from the spirit of the present invention.

[0064] For example, each cover unit 42 may be provided with an intermediate material different from the glass cloth 46. This intermediate material has higher mechanical strength than the non-combustible paper 44. Furthermore, it is preferable that this intermediate material has higher thermal insulation properties than the mica plate 48. Furthermore, it is preferable that this intermediate material has electrical insulation properties. Such intermediate materials include, for example, silica cloth or ceramic plate materials.

[0065] Furthermore, each cover unit 42 may be equipped with an insulating plate different from the mica plate 48. The electrical insulation properties of this insulating plate are higher than those of the non-combustible paper 44. Moreover, the electrical insulation properties of the insulating plate may be higher than those of the intermediate material. In addition, this insulating plate has higher mechanical strength than the non-combustible paper 44. Moreover, this insulating plate may have higher mechanical strength than the intermediate material. Such insulating plates include, for example, plates made of thermosetting resin. A specific example of a thermosetting resin is, for example, unsaturated polyester.

[0066] The cover unit 42 may be provided in a location different from the inner surface of the top plate portion 37 of the battery case 22. For example, if the battery device 20 is equipped with only four battery stacks 50A, 50C, 50F, and 50H, and release valves 54 are provided on the front surface of each battery cell 52 of battery stacks 50A and 50C and on the rear surface of each battery cell 52 of battery stacks 50F and 50H, the cover unit 42 may be provided on at least one of the front and rear portions of the peripheral wall portion 27 of the lower case 24 and the front and rear portions of the peripheral wall portion 38 of the upper case 35.

[0067] The non-combustible paper 44 of the cover unit 42 may be fixed to the inner surface of the battery case 22 using a heat-resistant adhesive. Similarly, the non-combustible paper 44 of the cover unit 42 and the intermediate material may be fixed with a heat-resistant adhesive, or the intermediate material and the insulating plate may be fixed with a heat-resistant adhesive.

[0068] The number of battery stacks 50 housed in the battery case 22 may be different from 8.

[0069] The battery stack 50 housed in the battery case 22 may comprise a plurality of battery cells 52 arranged in a direction different from the left-right direction. In this case, the insulating plate of the cover unit 42 extends in a direction parallel to the direction in which the battery cells 52 are arranged in a plan view, and the insulating plate faces the release valves 54 of the plurality of battery cells 52 in the thickness direction of the insulating plate.

[0070] The non-combustible paper 44 may be provided on the entire inner surface of the top plate portion 37 of the upper case 35, or on the entire inner surface of the upper case 35, or on the entire inner surface of the battery case 22.

[0071] The cover unit 42 may consist of the same number of opposing release valves 54 and may also comprise a plurality of insulating plates facing each release valve 54.

[0072] The vehicle may be an electric vehicle that is different from an electric vehicle and is equipped with an electric motor that utilizes the power of the battery device 20. For example, the vehicle may be a hybrid electric vehicle (HEV) or a plug-in hybrid electric vehicle (PHEV). [Explanation of Symbols]

[0073] 10 vehicles (electric vehicles) 20 Battery device 22 Battery Case (Case) 24 Lower Cases 24A Cationic coating 35 Upper Case 35A Cationic coating 37 Top panel 44 Non-combustible paper 46. ​​Glass cloth (intermediate material) 48 48A 48B 48C 48D 48E 48F 48G 48H Mica plate (insulating plate) 50 50A 50B 50C 50D 50E 50F 50G 50H Battery Stack 52 battery cells 53 Cell Case 54 Release valve 55 Internal electrodes (built-in components) GP3 gap

Claims

1. Multiple battery cells, each having a cell case equipped with a release valve that opens when the internal pressure reaches a predetermined value, A case for housing multiple of the aforementioned battery cells, Non-combustible paper provided on at least a portion of the inner surface of the case, An intermediate material is provided on the surface of the non-combustible paper opposite to the inner surface, and has higher mechanical strength than the non-combustible paper. An insulating plate is provided on the side of the intermediate material opposite to the non-combustible paper, facing the release valve, and having electrical insulation properties and higher mechanical strength than the non-combustible paper, Equipped with, A battery device in which the heat insulation properties of the non-combustible paper and the intermediate material are higher than those of the insulating plate.

2. The aforementioned case is made of a material containing iron, The battery device according to claim 1, wherein the inner surface of the case is coated with cationic paint.

3. The battery device according to claim 1 or claim 2, wherein the area of ​​the non-combustible paper and the intermediate material, when viewed in the thickness direction of the non-combustible paper, is greater than the area of ​​the insulating plate.

4. The battery device according to claim 1 or claim 2, wherein the intermediate material is glass cloth.

5. The battery device according to claim 1 or claim 2, wherein the insulating plate is a mica plate.

6. The aforementioned case is, Lower case and, The upper case, which is integrated with the lower case, and which together constitute the case with the lower case, Equipped with, The release valve is provided on the upper surface of the cell case. The battery device according to claim 1 or claim 2, wherein the non-combustible paper is provided on the ceiling portion of the inner surface of the upper case.

7. A battery stack having a plurality of the aforementioned battery cells arranged in a predetermined linear direction in a plan view is provided inside the case. The insulating plate is a plate material extending along the linear direction, The battery device according to claim 1 or claim 2, wherein a single insulating plate faces the release valves of a plurality of battery cells.

8. In a plan view, the multiple battery stacks are arranged with gaps forming in a direction perpendicular to the linear direction, The two insulating plates face each of the plurality of battery cells arranged in the linear direction, The battery device according to claim 7, wherein two insulating plates are provided on a single intermediate material that overlaps with the gap when viewed in the thickness direction of the non-combustible paper.

9. A single piece of the non-combustible paper is provided with a single piece of the intermediate material. When defining the direction perpendicular to the straight line direction when viewed in the thickness direction of the non-combustible paper as the orthogonal direction, The battery device according to claim 8, wherein one end of the non-combustible paper and the intermediate material in the orthogonal direction is located to the one side of the two insulating plates, and the other end of the non-combustible paper and the intermediate material in the orthogonal direction is located to the other side of the two insulating plates.

10. A battery device according to claim 1 or claim 2, mounted on an electric vehicle.

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