Power storage device and power storage device module

Abstract

To provide a power storage device capable of suppressing transmission of heat of a heated power storage device to an adjacent power storage device in a power storage device module.SOLUTION: Of the six case walls 11 to 16, the first case 11m 11 facing the stacking direction FH has the first outer side surface 11n and the first inner side surface 12m, and the second case 12n 12 facing the stacking direction FH has the second outer side surface wall and the second inner side surface wall. Of the outer side 10m and the inner side 10n of the case 10, at least one of the first outer side 11m, the first inner side 11n, the second outer side 12m, and the second inner side 12n is provided with the ceramic heat insulating layers 21A to 21D.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an electricity storage device having a rectangular box-shaped case, and to an electricity storage device module formed by stacking a plurality of such electricity storage devices. [Background technology]

[0002] Battery modules are known that are made up of a plurality of rectangular parallelepiped prismatic batteries stacked together. For example, Patent Document 1 (see Figures 1 to 3, etc., of Patent Document 1) is an example of related prior art. In the battery module of Patent Document 1, a plurality of prismatic batteries are stacked together with separator members interposed between them, and end plates are disposed on both ends of the battery module. Furthermore, restraining members are connected to the two end plates, restraining the array of prismatic batteries and separator members in the stacking direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-127064 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the prismatic battery cases are made of metal and have high thermal conductivity. Therefore, in the battery module, if one battery generates heat, the heat is transferred to the adjacent battery through the separator, causing the temperature of the adjacent battery to also rise.

[0005] The present invention has been made in consideration of the current situation, and provides an energy storage device in which, in an energy storage device module in which multiple rectangular energy storage devices are stacked side by side, when one energy storage device generates heat, the heat from the generated energy storage device can be prevented from being transferred to adjacent energy storage devices. [Means for solving the problem]

[0006] (1) One aspect of the present invention for solving the above problem is a rectangular energy storage device comprising an electrode body and a rectangular box-shaped case made of metal and consisting of six case walls that houses the electrode body, and which is stacked in a stacking direction to form an energy storage device module, wherein of the six case walls, a first case wall that faces the stacking direction has a first outer surface and a first inner surface, and a second case wall that faces the stacking direction and faces the first case wall has a second outer surface and a second inner surface, and at least one of the outer surface and inner surface of the case, the first outer surface, the first inner surface, the second outer surface, and the second inner surface, is provided with a ceramic heat insulating layer made of a material whose main component is ceramic and whose thermal conductivity is lower than that of the metal.

[0007] In the above-described electricity storage device, the ceramic insulating layer is provided only on at least one of the four surfaces (first outer surface, first inner surface, second outer surface, and second inner surface) of the first and second case wall portions facing the stacking direction among the outer and inner surfaces of the case. The ceramic insulating layer has low thermal conductivity. Therefore, in an electricity storage device module in which a plurality of such electricity storage devices are stacked together directly or via an intervening member, when a certain electricity storage device generates heat, the heat from the generated electricity storage device can be prevented from being transmitted to adjacent electricity storage devices more effectively than when a ceramic insulating layer is not provided on any of the first outer surface, first inner surface, second outer surface, and second inner surface. On the other hand, in the above-described electricity storage device, the ceramic insulating layer is not provided on the outer and inner surfaces of the remaining four case wall portions among the outer and inner surfaces of the case. Therefore, heat from the electricity storage device can be efficiently dissipated through these four case walls.

[0008] (2) In the electricity storage device according to (1), the metal forming the case may be aluminum, and the ceramic heat insulating layer may be an alumite coating.

[0009] (3) Furthermore, in the energy storage device described in (1) or (2), it is preferable that, among the six case walls, a third outer surface of a third case wall connecting the first case wall and the second case wall has a large number of protrusions and recesses formed thereon, and the energy storage device includes an area-increasing portion that has been subjected to an area-increasing treatment to increase the contact area of ​​the energy storage device module that comes into contact with the coolant.

[0010] (4) Furthermore, in the energy storage device described in (3), the area-increasing portion may be an energy storage device in which the protrusions are made of nanopillars with a height of 50 nm or more, each of which is formed by particles derived from the metal that forms the case being linked together in a string-like pattern, and the recesses are formed between the nanopillars.

[0011] (5) Yet another aspect is an electricity storage device module formed by stacking a plurality of electricity storage devices according to any one of (1) to (4) in the stacking direction.

[0012] (6) Furthermore, in the electric storage device module according to (5), it is preferable that the electric storage device module is configured by stacking a plurality of the electric storage devices in the stacking direction with a heat insulating member interposed therebetween. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a perspective view of a battery according to an embodiment. [Figure 2] FIG. 3 is a partially enlarged cross-sectional view of a first case wall and a second case wall in the embodiment. [Figure 3] FIG. 4 is a partially enlarged cross-sectional view of a third case wall in the embodiment. [Figure 4] FIG. 3 is a partially enlarged cross-sectional view of a fourth case wall portion, a fifth case wall portion, and a sixth case wall portion in the embodiment. [Figure 5] 2 is a partial cross-sectional view taken along the longitudinal direction and the stacking direction of the battery module according to the embodiment; FIG. [Figure 6] 10 is an explanatory diagram illustrating an enlarged view of a contact portion between a third outer surface (increased area portion) of the battery and a coolant in the embodiment. FIG. [Figure 7] FIG. 10 is an explanatory diagram showing how a pulsed laser beam is scanned to form a plurality of bowl-shaped recesses and nano-columns standing tall in each of the bowl-shaped recesses on the third outer surface of the third case wall, in relation to the manufacturing method of the battery according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. A battery (electricity storage device) 1 of this embodiment is a rectangular (cuboid) sealed lithium ion secondary battery that is installed in vehicles such as hybrid cars, plug-in hybrid cars, and electric cars. The battery height direction AH, battery width direction BH, and battery thickness direction CH of battery 1 will be defined as the directions shown in FIG. 1. This battery 1 is composed of a case 10, an electrode assembly 30 and an electrolyte 5 housed in the case 10, a positive terminal 40, a negative terminal 50, and the like, each supported by the case 10 (see FIG. 1).

[0015] The electrode assembly 30 is a rectangular parallelepiped laminate, consisting of multiple positive electrode plates 31 and multiple negative electrode plates 32 alternately stacked with separators 33 interposed between them, each of which is a porous resin film. The positive electrode plates 31, negative electrode plates 32, and separators 33 each have a rectangular shape extending in the battery height direction AH and the battery width direction BH. On one side BH1 of the electrode assembly 30 in the battery width direction BH, the current collector foils of each positive electrode plate 31 extend toward the other side BH1 and overlap with each other to form a positive electrode current collector portion 30c. A positive electrode terminal 40 is welded to this positive electrode current collector portion 30c. On the other side BH2 of the electrode assembly 30 in the battery width direction BH, the current collector foils of each negative electrode plate 32 extend toward the other side BH2 and overlap with each other to form a negative electrode current collector portion 30d. To this negative electrode current collecting portion 30d, a negative electrode terminal 50 is welded. The electrode body 30 is covered within the case 10 by a bag-shaped insulating holder (not shown) made of insulating film.

[0016] The case 10 is made of metal (aluminum in this embodiment). The case 10 is shaped like a rectangular parallelepiped box and is composed of a first case wall 11, a second case wall 12, a third case wall 13, a fourth case wall 14, a fifth case wall 15, and a sixth case wall 16, each of which is a rectangular plate (see Figures 2 to 4 in addition to Figure 1). The first case wall 11 and the second case wall 12 have a larger area than the remaining four case walls 13, 14, 15, and 16. The first case wall 11 and the second case wall 12 face each other, with the first case wall 11 located on one side CH1 of the battery thickness direction CH and the second case wall 12 located on the other side CH2 of the battery thickness direction CH. The remaining four case walls 13, 14, 15, and 16 connect the first case wall 11 and the second case wall 12. The third case wall 13 and the fourth case wall 14 face each other, with the third case wall 13 located on the lower side AH2 in the battery height direction AH and the fourth case wall 14 located on the upper side AH1 in the battery height direction AH. The fifth case wall 15 and the sixth case wall 16 face each other, with the fifth case wall 15 located on one side BH1 in the battery width direction BH and the sixth case wall 16 located on the other side BH2 in the battery width direction BH.

[0017] The case 10 is formed by joining a case body member 18 and a case lid member 19. The case body member 18 is a rectangular cylinder with a bottom and a rectangular opening 18c. The case lid member 19 is a rectangular plate and closes the opening 18c of the case body member 18. The opening 18c of the case body member 18 and the peripheral edge 19f of the case lid member 19 are hermetically welded along their entire periphery. The case body member 18 forms the first case wall 11, second case wall 12, third case wall 13, fifth case wall 15, and sixth case wall 16 of the case 10. The case lid member 19 forms the fourth case wall 14 of the case 10.

[0018] The fourth case wall 14, which also serves as the upper wall of the case 10, is provided with a safety valve 10w that ruptures and opens when the internal pressure of the case 10 exceeds a valve-opening pressure. The fourth case wall 14 is also provided with a liquid inlet (not shown), which is airtightly sealed with a disk-shaped sealing member 17. A positive electrode terminal 40 and a negative electrode terminal 50 are fixed to the fourth case wall 14. Specifically, the fourth case wall 14 is provided with a pair of insertion holes (not shown), with the positive electrode terminal 40 made of aluminum inserted into one of the insertion holes and the negative electrode terminal 50 made of copper inserted into the other insertion hole. The positive electrode terminal 40 is fixed to the fourth case wall 14 via an insert-molded resin member 45, and the negative electrode terminal 50 is fixed to the fourth case wall 14 via an insert-molded resin member 55. As described above, the positive electrode terminal 40 is conductively connected to the positive electrode current collecting portion 30c of the electrode body 30, and the negative electrode terminal 50 is conductively connected to the negative electrode current collecting portion 30d of the electrode body 30.

[0019] The outer side surface 10m of the case 10 is made up of six rectangular surfaces: a first outer side surface 11m of the first case wall 11, a second outer side surface 12m of the second case wall 12, a third outer side surface 13m of the third case wall 13, a fourth outer side surface 14m of the fourth case wall 14, a fifth outer side surface 15m of the fifth case wall 15, and a sixth outer side surface 16m of the sixth case wall 16. On the other hand, the inner side surface 10n of the case 10 is made up of six rectangular surfaces: a first inner side surface 11n of the first case wall 11, a second inner side surface 12n of the second case wall 12, a third inner side surface 13n of the third case wall 13, a fourth inner side surface 14n of the fourth case wall 14, a fifth inner side surface 15n of the fifth case wall 15, and a sixth inner side surface 16n of the sixth case wall 16.

[0020] Of the outer surfaces 10m of the case 10, a ceramic insulation layer 21A is provided over the entire surface of the first outer surface 11m of the first case wall 11, and a ceramic insulation layer 21B is also provided over the entire surface of the second outer surface 12m of the second case wall 12 (see FIG. 2). On the other hand, of the outer surfaces 10m of the case 10, none of the remaining third outer surface 13m of the third case wall 13, fourth outer surface 14m of the fourth case wall 14, fifth outer surface 15m of the fifth case wall 15, and sixth outer surface 16m of the sixth case wall 16 are provided with a ceramic insulation layer (see FIGS. 3 and 4).

[0021] Of the inner surfaces 10n of the case 10, a ceramic heat insulating layer 21C is provided on the first inner surface 11n of the first case wall 11, and a ceramic heat insulating layer 21D is provided on the second inner surface 12n of the second case wall 12 (see FIG. 2). On the other hand, of the inner surfaces 10n of the case 10, no ceramic heat insulating layer is provided on any of the remaining third inner surface 13n of the third case wall 13, fourth inner surface 14n of the fourth case wall 14, fifth inner surface 15n of the fifth case wall 15, and sixth inner surface 16n of the sixth case wall 16 (see FIGS. 3 and 4).

[0022] These ceramic heat insulating layers 21A, 21B, 21C, and 21D are made of a material whose main component is ceramic (amorphous alumina (Al2O3) in this embodiment) and whose thermal conductivity is lower than that of the metal (aluminum in this embodiment) that forms the case 10. Specifically, the ceramic heat insulating layers 21A to 21D are anodized aluminum coatings with a thickness of 20 to 100 μm (50 μm in this embodiment). The thermal conductivity of the anodized aluminum coating that forms the ceramic heat insulating layers 21A to 21D is only about one-third that of the aluminum that forms the case 10.

[0023] Here, a method for forming the ceramic thermal insulation layers 21A-21D will be described. The ceramic thermal insulation layers 21A-21D are formed by anodization. Specifically, first, a case body member 18 before anodization is prepared, and masking tape is applied to each of the surfaces other than the first outer side surface 11m, the second outer side surface 12m, the first inner side surface 11n, and the second inner side surface 12n, i.e., the third outer side surface 13m, the fifth outer side surface 15m, the sixth outer side surface 16m, the third inner side surface 13n, the fifth inner side surface 15n, and the sixth inner side surface 16n, to mask these surfaces. Next, the masked case body member 18 is immersed in an electrolytic solution, and electricity is passed through the case body member 18 as the anode, thereby forming ceramic thermal insulation layers 21A-21D made of oxide films (i.e., almanite coatings) on the exposed surfaces of the case body member 18, i.e., the first outer surface 11m, the second outer surface 12m, the first inner surface 11n, and the second inner surface 12n. Thereafter, the case body member 18 with the ceramic thermal insulation layers 21A-21D formed thereon is removed from the electrolytic solution, and the masking tape is peeled off. In this manner, the case body member 18 provided with the ceramic thermal insulation layers 21A-21D is obtained.

[0024] Among the outer surfaces 10m of the case 10, the third outer surface 13m of the third case wall 13, which is also the bottom wall, has an area-increasing portion 26 that has been subjected to an area-increasing process to form a large number of protrusions 26t and recesses 26v and increase the contact area Sa that comes into contact with the coolant 145 of the battery module (electricity storage device module) 100 (described later) (see FIGS. 3 and 6). In this embodiment, the entire third outer surface 13m constitutes the area-increasing portion 26. The surface area of ​​the area-increasing portion 26 is preferably three times or more larger than the surface area before the area-increasing process, and in this embodiment, it is approximately 20 times larger.

[0025] The area-increased portion 26 in this embodiment is a nano-roughened portion at the nano-level (nano-order). Specifically, the area-increased portion 26 includes numerous bowl-shaped depressions 27, each with a diameter of 30 to 300 μm (approximately 80 μm in this embodiment), arranged in a partially overlapping arrangement (see FIG. 7). Furthermore, these bowl-shaped depressions 27 are forested with protrusions 26t consisting of nanopillars 28, each of which is formed by a string of particles 28p derived from the metal constituting the case 10, and each having a height ha of 50 nm or more but less than 1000 nm (approximately ha = 200 nm in this embodiment). Recesses 26v are formed between the forest of nanopillars 28 (see FIG. 6). The metal constituting the case 10 is aluminum, as described above, and the nanopillars 28 are made of particles 28p composed of aluminum and aluminum oxide.

[0026] Here, the area increasing process for forming the area increasing portion 26 will be described (see FIG. 7). In this embodiment, a case body member 18 before the area increasing process is prepared, and the entire third outer surface 13m of the third case wall portion 13 is subjected to the surface increasing process to form the area increasing portion 26 having numerous convex portions 26t and concave portions 26v on the entire third outer surface 13m. Specifically, pulsed laser light LB is intermittently irradiated onto the third outer surface 13m while shifting the irradiation position, thereby forming the area increasing portion 26 in which numerous cup-shaped concave portions 27 each having a forest of nanopillars 28 are arranged in a partially overlapping manner (see FIG. 7). The laser irradiation conditions were a wavelength of 1064 nm, a peak output of 5 kW, a pulse width of 150 ns, a pitch pb of 75 μm, and a spot diameter of 80 μm.

[0027] At the portion of the third outer surface 13m irradiated with the pulsed laser beam LB, the metal (aluminum in this embodiment) near the surface melts and turns into vapor. Then, as the temperature of the vapor drops, it turns into aluminum and aluminum oxide particles 28p and deposits in the bowl-shaped recess 27. By intermittently irradiating the third outer surface 13m with the pulsed laser beam LB while shifting the irradiation position, the particles 28p deposit and bond together in a string of beads to form columns, forming a forest of nano-columns 28. The increased-area portion 26 may be formed after or before the ceramic thermal insulating layers 21A-21D are formed on the case body member 18.

[0028] Next, a battery module 100 formed by stacking a plurality of the above-described batteries 1 will be described (see FIG. 5). The battery module 100 includes a plurality of batteries 1, a plurality of heat insulating members (each a plurality of first heat insulating members 120 and second heat insulating members 125), a pair of end plates 130, a cooler 140, a module case 150, etc.

[0029] The batteries 1 constituting the battery module 100 are stacked in a row in the stacking direction FH. Specifically, the batteries 1 are alternately oriented so that the battery height direction AH coincides with the longitudinal direction DH of the battery module 100, the battery width direction BH coincides with the lateral direction EH of the battery module 100, and the battery thickness direction CH coincides with the stacking direction FH. Therefore, in this embodiment, the first case wall 11 and the second case wall 12 of the case 10 each face in the stacking direction FH (i.e., the normals of the first case wall 11 and the second case wall 12 each face in the stacking direction FH). The positive terminal 40 of one adjacent battery 1 and the negative terminal 50 of the other adjacent battery 1 are aligned in the stacking direction FH and are electrically connected (connected in series) via a rectangular plate-shaped bus bar 110. The bus bar 110 is welded to the positive terminal 40 and the negative terminal 50, respectively.

[0030] The heat insulating members 120 and 125 are disposed between adjacent batteries 1. Each of the heat insulating members 120 and 125 has a rectangular plate shape and is in contact with substantially the entire surface of the first outer surface 11m of the first case wall 11 and the second outer surface 12m of the second case wall 12 of the battery 1. The first heat insulating member 120 is made of insulating ceramic (alumina in this embodiment), and the second heat insulating member 125 is made of insulating elastic material (ethylene propylene diene rubber (EPDM) in this embodiment). By using not only the hard first heat insulating member 120 but also the elastic second heat insulating member 125 as the heat insulating members, expansion and contraction of each battery 1 in the battery thickness direction CH (stacking direction FH) that occurs during charging and discharging can be absorbed.

[0031] A pair of end plates 130 are arranged on both ends of the aligned batteries 1 and heat insulating members 120, 125. The end plates 130 are made of aluminum. A plurality of restraining members 135 are connected to the pair of end plates 130 and span the space between them, and the aligned batteries 1 and heat insulating members 120, 125 are restrained by the end plates 130 and the restraining members 135 while being pressed in the stacking direction FH.

[0032] The cooler 140 is disposed below the row of batteries 1 and heat insulating members 120, 125 in the vertical direction DH, on the lower side DH2, and is in contact with each battery 1. The cooler 140 has a cooler body 141 and a coolant 145 disposed thereon. The cooler body 141 is made of aluminum and has a generally rectangular plate shape extending in the stacking direction FH, and has a flow path 142 formed therein that extends in the stacking direction FH. A cooling medium RB (water in this embodiment) flows through the flow path 142 when the battery module 100 is in use.

[0033] In this embodiment, the coolant 145 is a thermally conductive gel sheet having a rectangular plate shape. The coolant 145 is sandwiched between the cooler body 141 and each battery 1, and contacts the cooler body 141 on the lower side DH2 in the vertical direction DH, while contacting the entire surface of the third outer surface 13m (increased-area portion 26) of the third case wall portion 13 of each battery 1 on the upper side DH1 in the vertical direction DH. Specifically, the numerous protrusions 26t formed in the increased-area portion 26 bite into the coolant 145, and the coolant 145 bites into the numerous recesses 26v formed in the increased-area portion 26, increasing the contact area Sa between the third outer surface 13m and the coolant 145. In this embodiment, as described above, the surface area of ​​the area-increasing portion 26 is increased by more than three times (specifically, about 20 times) compared to the surface area before the area-increasing process, and therefore the contact area Sa between the area-increasing portion 26 and the coolant 145 is also increased by more than three times (specifically, about 20 times).

[0034] The module case 150 is made of aluminum. The module case 150 has a lower case 151 that houses the aforementioned battery 1, heat insulating members 120, 125, end plate 130, cooler 140, etc., and an upper case 152 that is fixed to the lower case 151 at an upper side DH1 of the lower case 151. The end plate 130 and the cooler main body 141 of the cooler 140 are each fixed to the lower case 151.

[0035] In the battery 1 of this embodiment, ceramic thermal insulating layers 21A, 21B, 21C, and 21D are provided only on four surfaces (first outer surface 11m, first inner surface 11n, second outer surface 12m, and second inner surface 12n) of the outer surface 10m and inner surface 10n of the case 10 that face the stacking direction FH of the first case wall 11 and the second case wall 12. The ceramic thermal insulating layers 21A-21D have low thermal conductivity. Therefore, in a battery module 100 in which multiple batteries 1 are stacked, when a battery 1 generates heat, the heat transfer from the generated battery 1 to adjacent batteries 1 can be suppressed more effectively than in a case in which the ceramic thermal insulating layers 21A-21D are not provided. On the other hand, in the battery 1, ceramic thermal insulating layers are not provided on the outer surfaces 13m-16m and inner surfaces 13n-16n of the remaining four case walls 13-16 of the outer surface 10m and inner surface 10n of the case 10. Therefore, heat from the battery 1 can be efficiently dissipated through these four case walls 13-16.

[0036] Furthermore, in this embodiment, since the ceramic heat insulating layers 21A-21D are anodized aluminum films, the ceramic heat insulating layers 21A-21D can be easily formed on the case 10 by anodization, and the battery 1 can be made inexpensively. In this embodiment, the third outer surface 13m of the third case wall 13 of the case 10 has a large number of protrusions 26t and recesses 26v, forming an area increasing portion 26 that increases the contact area Sa with the coolant 145. Therefore, in the battery module 100, each battery 1 can be cooled more efficiently through the third case wall 13. Furthermore, the area increase portion 26 is a nano-level area increase portion in which nano-pillars 28 stand in rows. Therefore, in the battery module 100, the contact area Sa between the third case wall portion 13 of the battery 1 and the coolant 145 is particularly large, and each battery 1 can be cooled more efficiently.

[0037] In addition, in the battery module 100 of this embodiment, multiple batteries 1 are stacked with the heat insulating members 120, 125 interposed between them, and therefore adjacent batteries 1 can be effectively insulated from each other by the ceramic heat insulating layers 21A-21D provided on the case 10 and the heat insulating members 120, 125. Furthermore, by providing the ceramic heat insulating layers 21A-21D, the heat insulating members 120, 125 can be made thinner.

[0038] Although the present invention has been described above in accordance with the embodiments, it goes without saying that the present invention is not limited to the embodiments and can be modified and applied as appropriate within the scope of the invention. For example, in the embodiment, a lithium ion secondary battery is exemplified as the power storage device, but the present invention is not limited to this. Examples of the power storage device include secondary batteries such as sodium ion secondary batteries and calcium ion secondary batteries, and capacitors such as lithium ion capacitors.

[0039] In the embodiment, the ceramic heat insulating layers 21A-21D are provided on the entire first outer surface 11m, the first inner surface 11n, etc. However, this is not limited to this. The ceramic heat insulating layers 21A-21D may be provided on only a part of the first outer surface 11m, the first inner surface 11n, etc. In the embodiment, the ceramic heat insulating layers 21A-21D are formed by anodization, but this is not limiting. For example, the ceramic heat insulating layers 21A-21D can also be formed by ceramic spraying, or by applying a ceramic paste containing ceramic powder, binder, etc. to the case wall and drying it.

[0040] In the embodiment, the area increasing process is exemplified by the process of forming nano-level protrusions 26t and recesses 26v by irradiating with pulsed laser light LB, but is not limited thereto. Examples of the area increasing process include physical area increasing processes such as shot blasting, sand blasting, and metal spraying, and chemical area increasing processes such as chemical etching. The area increasing process may also be an area increasing process in which a large number of protrusions and recesses are formed by pressing third case wall 13, or an area increasing process in which a large number of protrusions and recesses are formed in third case wall 13 using a casting mold when casting case 10. In the embodiment, the area increasing portion 26 is provided on the entire third outer surface 13m of the third case wall portion 13, but this is not limitative. The area increasing portion 26 may be provided on only a part of the third outer surface 13m.

[0041] Furthermore, in the embodiment, the plurality of batteries 1 included in the battery module 100 are connected in series, but the batteries 1 may also be connected in parallel. In the embodiment, the battery module 100 is illustrated as having a plurality of batteries 1 stacked in a single row, but the present invention is not limited to this and may also be a battery module having a plurality of rows of batteries 1 stacked in multiple rows. In a battery module having a plurality of rows of batteries 1 stacked in multiple rows, adjacent rows may be arranged with a gap between them, or may be arranged without a gap between them with a thermal insulating member such as the first thermal insulating member 120 or the second thermal insulating member 125 interposed therebetween.

[0042] In the embodiment, a thermally conductive gel sheet is exemplified as the coolant 145, but the coolant 145 is not limited to this. Examples of the coolant 145 include thermally conductive grease applied in layers, and a thermally conductive resin plate formed by applying and hardening a liquid resin material in layers. In the embodiment, the electrode body is exemplified as a laminated electrode body 30, but is not limited thereto. The electrode body may be, for example, a flat wound electrode body in which a strip-shaped positive electrode plate and a strip-shaped negative electrode plate are wound flatly with a pair of strip-shaped separators interposed therebetween. [Explanation of symbols]

[0043] 1. Battery (energy storage device) 10 cases 10m (outside of case) 10n (case) inner surface 11 First case wall 11m 1st outer surface 11n 1st inner surface 12 Second case wall 12m 2nd outer surface 12n 2nd inner surface 13 Third case wall 13m 3rd outer surface 14 Fourth case wall 15 Fifth case wall 16 Sixth case wall 21A, 21B, 21C, 21D Ceramic insulation layer 26 Area increase section 26t convex part 26v recess 28 Nano Pillars 28p particles 30 Electrode body 100 Battery module (electricity storage device module) 120 First heat insulating member 125 Second insulating member 140 Cooler 145 Coolant FH Overlap direction Sa contact area

Claims

1. An electrode body; a rectangular parallelepiped box-shaped case that houses the electrode assembly, is made of metal, and is composed of six case walls; Multiple devices are stacked in the stacking direction to form an energy storage device module. A rectangular electricity storage device, Of the six case walls, the first case wall portion facing the stacking direction has a first outer surface and a first inner surface, a second case wall portion facing the stacking direction and facing the first case wall portion has a second outer surface and a second inner surface; A ceramic heat insulating layer made of a material containing ceramic as a main component and having a thermal conductivity lower than that of the metal is provided only on at least one of the first outer surface, the first inner surface, the second outer surface, and the second inner surface among the outer and inner surfaces of the case. Energy storage device.

2. The electricity storage device according to claim 1 , the metal forming the case is aluminum; The ceramic heat insulating layer is an anodized aluminum coating. Energy storage device.

3. The electricity storage device according to claim 1 or 2, Among the six case walls, a third outer surface of a third case wall connecting the first case wall and the second case wall is The area increasing portion is formed by forming a large number of protrusions and recesses, and is subjected to an area increasing process to increase the contact area of ​​the power storage device module that comes into contact with the coolant. Energy storage device.

4. The electricity storage device according to claim 3, The area increasing portion is The protrusions are made of nanopillars with a height of 50 nm or more, each of which is formed by connecting particles derived from the metal forming the case in a string-like pattern, and the recesses are formed between the nanopillars. Energy storage device.

5. A plurality of the power storage devices according to claim 1 or 2 are stacked in the stacking direction. Energy storage device module.

6. The electricity storage device module according to claim 5, A plurality of the power storage devices are stacked in the stacking direction with heat insulating members interposed therebetween. Energy storage device module.

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