Power storage device and cooling structure for power storage device

Abstract

To provide a power storage device capable of improving thermal conduction from a case of the power storage device to a thermally conductive material.SOLUTION: A battery 1 includes an electrode assembly 40 and a metal case 10 that houses the electrode assembly 40. The case 10 has a case outer surface 11 that is exposed to the outside. The case outer surface 11 faces a cooling surface 130m of a cooler 130 and includes a heat dissipation portion 18 that dissipates heat toward the cooling surface 130m via a thermally conductive material 140. The heat dissipation portion 18 of the case outer surface 11 includes an area increasing portion 19 that has been subjected to an area increasing treatment to form a large number of protrusions 19t and recesses 19v and increase the specific surface area Sb.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to an electricity storage device including a heat dissipation section on the outer surface of a case that faces a cooling surface of a cooler and dissipates heat toward the cooling surface via a thermally conductive material, and a cooling structure for an electricity storage device including this electricity storage device. [Background technology]

[0002] Conventionally, a battery pack is known that includes a battery, a cooler that cools the battery, and a thermally conductive material (such as thermally conductive grease or a thermally conductive sheet) that is disposed between the battery and the cooler to transfer heat from the battery to the cooler. For example, Patent Document 1 is an example of related prior art (see FIG. 2 of Patent Document 1, etc.). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2023-046725 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in conventional battery packs, heat transfer from the battery case to the thermally conductive material is insufficient, making it difficult to adequately cool the battery.

[0005] The present invention has been made in consideration of the current situation, and provides an electricity storage device that can improve thermal conduction from a case of the electricity storage device to a thermally conductive material, and a cooling structure for the electricity storage device that includes this electricity storage device. [Means for solving the problem]

[0006] (1) One aspect of the present invention for solving the above problems is an electricity storage device comprising an electrode body and a metal case that houses the electrode body, the case having an outer case surface exposed to the outside, the outer case surface facing a cooling surface of a cooler, and including a heat dissipation section that dissipates heat toward the cooling surface via a thermally conductive material, the heat dissipation section on the outer case surface including an area increasing section that has been subjected to an area increasing treatment to form a large number of protrusions and recesses to increase a specific surface area.

[0007] In the above-mentioned electric storage device, the heat dissipation part on the outer surface of the case of the electric storage device includes an area-increasing part in which a large number of convex parts and concave parts are formed by the area-increasing treatment and the specific surface area is increased compared to the specific surface area before the treatment. Therefore, the heat dissipation part of the electric storage device and the thermal conductive material can be in contact with each other over a larger contact area than when the heat dissipation part does not have the area-increasing part. This makes it possible to improve the thermal conduction from the heat dissipation part of the electric storage device to the thermal conductive material compared to when the heat dissipation part does not have the area-increasing part.

[0008] Examples of the "electricity storage device" include secondary batteries such as lithium ion secondary batteries, sodium ion secondary batteries, and calcium ion secondary batteries, and capacitors such as lithium ion capacitors. Examples of the "area increasing treatment" include physical surface roughening treatment such as shot blasting, sand blasting, metal spraying, etc., chemical surface roughening treatment such as anodization, chemical etching, etc., and surface roughening treatment for forming nano-order convex portions and concave portions by irradiating a pulsed laser. Alternatively, an area increasing treatment for forming an area-increased portion having a large number of convex portions and concave portions by pressing may be used. The area increasing portion may be formed only on a part of the heat dissipation portion on the outer surface of the case, or may be formed on the entire heat dissipation portion. Furthermore, a large number of protrusions and recesses similar to the large number of protrusions and recesses of the area increasing portion may be formed on the outer surface of the case other than the heat dissipation portion.

[0009] Examples of the "thermal conductive material" include thermally conductive grease applied in layers, thermally conductive gel sheets, and thermally conductive resin plates formed by applying and hardening layers of liquid resin material. An example of the "cooler" is a cooler having an internal cooling passage through which a cooling medium such as cooling air or cooling liquid flows.

[0010] (2) The energy storage device according to (1) may be an energy storage device in which the case has an inner case surface exposed to the inside, the inner case surface includes an electrode contact portion that directly or indirectly contacts the electrode body, and the specific surface area of ​​the area-increasing portion of the outer case surface is larger than the specific surface area of ​​the electrode contact portion of the inner case surface.

[0011] In the above-described electricity storage device, the electrode contact portion on the inner surface of the case is in close contact with the electrode body, so that even if the specific surface area of ​​the electrode contact portion is small, the heat of the electrode body can be appropriately transferred to the case. On the other hand, because variations in the attitude (inclination) of the power storage device can cause variations in the gap between the heat dissipation part on the outer surface of the case and the cooling surface of the cooler, the ease of heat transfer (ease of heat dissipation) from the case to the thermally conductive material is likely to vary, and this can easily become a barrier to heat dissipation. Therefore, it is preferable to increase the specific surface area of ​​the area-increasing part on the outer surface of the case compared to the specific surface area of ​​the electrode contact part on the inner surface of the case, thereby increasing the contact area between the heat dissipation part on the outer surface of the case and the thermally conductive material, thereby improving the thermal conduction from the heat dissipation part to the thermally conductive material.

[0012] (3) In the electric storage device according to (1) or (2), the area increasing treatment may be performed only on the heat dissipation portion of the outer surface of the case.

[0013] In the above-mentioned electricity storage device, there is no need to perform area-increasing treatment on parts of the outer surface of the case other than the heat dissipation section, so it is possible to produce an inexpensive electricity storage device while ensuring heat dissipation from the electricity storage device to the thermally conductive material.

[0014] (4) Yet another aspect is an electric storage device cooling structure comprising an electric storage device according to any one of (1) to (3), the cooler, and the thermally conductive material interposed between the heat dissipation portion of the electric storage device and the cooling surface of the cooler, in which a large number of the convex portions of the area increasing portion penetrate into the thermally conductive material, and the thermally conductive material penetrates into a large number of the concave portions of the area increasing portion, thereby increasing the contact area between the heat dissipation portion of the electric storage device and the thermally conductive material.

[0015] In the above-mentioned electricity storage device cooling body, the numerous protrusions formed in the area increasing portion bite into the thermally conductive material, and the thermally conductive material bites into the numerous recesses formed in the area increasing portion, thereby increasing the contact area between the heat dissipation portion of the electricity storage device and the thermally conductive material. This improves the thermal conduction from the heat dissipation portion of the electricity storage device to the thermally conductive material, and allows the electricity storage device to be appropriately cooled. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a perspective view of a battery according to an embodiment. [Diagram 2] FIG. 2 is a bottom view of the battery according to the embodiment. [Diagram 3] 1 is a cross-sectional view of a battery according to an embodiment of the present invention taken along the battery height direction and the battery thickness direction. [Figure 4] 2 is a partial cross-sectional view taken along the longitudinal direction and the row arrangement direction of the battery pack according to the embodiment; FIG. [Diagram 5] 5 is an enlarged cross-sectional view showing a portion A in FIG. 4 of the battery pack according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 shows a perspective view of a battery (electricity storage device) 1 of this embodiment, Fig. 2 shows a bottom view of the battery 1, and Fig. 3 shows a cross-sectional view of the battery 1. Fig. 4 shows a partial cross-sectional view of a battery pack (electricity storage device cooling structure) 100, and Fig. 5 shows an enlarged view of part A in Fig. 4 of the battery pack 100. In the following description, the battery height direction AH, battery width direction BH, and battery thickness direction CH of the battery 1 are defined as the directions shown in Figs. 1 to 3, and the longitudinal direction DH, lateral direction EH, and row arrangement direction FH of the battery pack 100 are defined as the directions shown in Figs. 4 and 5.

[0018] The battery pack 100 is mounted on vehicles such as hybrid cars, plug-in hybrid cars, and electric cars. The battery pack 100 includes a plurality of batteries 1. The battery 1 is a square (rectangular) sealed lithium ion secondary battery, and is composed of a case 10, an electrode body 40 and an electrolyte 5 housed in the case 10, a positive terminal 50 and a negative terminal 60 supported by the case 10, and the like (see Figs. 1 to 3). The electrode body 40 is made of an insulating film, and is covered by a bag-shaped insulating holder 7 with an open upper side AH1 in the battery height direction AH.

[0019] The case 10 is a rectangular box made of metal (aluminum in this embodiment), and is a bottomed square cylinder having a rectangular opening 31c. The case 10 is composed of a case body member 31 that houses the electrode body 40 therein and a rectangular plate-shaped case lid member 32 that closes the opening 31c of the case body member 31. The opening 31c of the case body member 31 and the peripheral portion 32f of the case lid member 32 are hermetically welded all around. The case lid member 32 is provided with a safety valve 35 that breaks and opens when the internal pressure of the case 10 exceeds a valve opening pressure. The case lid member 32 is also provided with a liquid injection hole 32k, which is hermetically sealed with a disk-shaped sealing member 36 made of aluminum.

[0020] In addition, rectangular through-holes (not shown) are provided in the vicinity of the ends of the one side BH1 and the other side BH2 of the case lid member 32 in the battery width direction BH. A positive electrode terminal 50 made of aluminum is inserted into the through-hole of the one side BH1, and the positive electrode terminal 50 is fixed to the case lid member 32 in a state insulated from the case lid member 32 via a resin member 55. The positive electrode terminal 50 is welded to a positive electrode current collector 40c (described later) of the electrode body 40 in the case 10, and is conductively connected to the positive electrode current collector 40c. In addition, a negative electrode terminal 60 made of copper is inserted into the through-hole of the other side BH2, and the negative electrode terminal 60 is fixed to the case lid member 32 in a state insulated from the case lid member 32 via a resin member 65. The negative electrode terminal 60 is welded to a negative electrode current collector 40d (described later) of the electrode body 40 in the case 10, and is conductively connected to the negative electrode current collector 40d.

[0021] The electrode body 40 is a rectangular parallelepiped laminated type, and is formed by alternately laminating a plurality of rectangular positive electrode plates 41 and a plurality of rectangular negative electrode plates 42 in the battery thickness direction CH with rectangular separators 43 made of a resin porous film interposed therebetween. On one side BH1 of the electrode body 40 in the battery width direction BH, the current collector foils of the positive electrode plates 41 overlap in the battery thickness direction CH to form a positive electrode current collector 40c. This positive electrode current collector 40c is conductively connected to the positive electrode terminal 50. On the other side BH2 of the electrode body 40 in the battery width direction BH, the current collector foils of the negative electrode plates 42 overlap in the battery thickness direction CH to form a negative electrode current collector 40d. This negative electrode current collector 40d is conductively connected to the negative electrode terminal 60.

[0022] Next, the case outer surface 11 of the case 10 that is exposed to the outside of the case 10 will be described in detail. The case outer surface 11 has an upper surface 12, a lower surface 13, a first wide side surface 14, a second wide side surface 15, a first narrow side surface 16, and a second narrow side surface 17, each of which has a rectangular shape. The upper surface 12 is located on an upper side AH1, and the lower surface 13 is located on a lower side AH2. The first wide side surface 14, the second wide side surface 15, the first narrow side surface 16, and the second narrow side surface 17 all have the same dimensions in the battery height direction AH, but the dimensions in the direction perpendicular to the battery height direction AH (battery width direction BH or battery thickness direction CH) of the first wide side surface 14 and the second narrow side surface 15 are larger than the first narrow side surface 16 and the second narrow side surface 17, so that the areas of the first wide side surface 14 and the second wide side surface 15 are larger than the areas of the first narrow side surface 16 and the second narrow side surface 17. The first wide side surface 14 is located on one side CH1 in the battery thickness direction CH, and the second wide side surface 15 is located on the other side CH2 in the battery thickness direction CH. The first narrow side surface 16 is located on one side BH1 in the battery width direction BH, and the second narrow side surface 17 is located on the other side BH2 in the battery width direction BH.

[0023] The case outer surface 11 faces a cooling surface 130m of a cooler 130 (see Figs. 4 and 5) described later, and includes a heat dissipation section 18 that dissipates heat toward the cooling surface 130m via a heat conductive member (thermal conductive material) 140. In this embodiment, the entire lower surface 13 of the case outer surface 11 corresponds to the heat dissipation section 18. This heat dissipation section 18 (lower surface 13) includes an area-increasing section 19 having a large number of convex portions 19t and concave portions 19v (shown by dots in Fig. 2) formed thereon by performing an area-increasing treatment (metal spraying in this embodiment) and having an increased specific surface area Sb compared to the specific surface area Sa before the treatment. In this embodiment, the entire heat dissipation section 18 corresponds to the increased area section 19. The specific surface area Sb of this increased area section 19 is preferably about 3 to 20 times larger than the specific surface area Sa before the area-increasing treatment, and is about 5 times larger in this embodiment (Sb / Sa is about 5). The specific surface areas Sa and Sb can be obtained by measuring the BET specific surface area by a gas adsorption method using Kr gas.

[0024] In this embodiment, the above-mentioned area-increased portion 19 is provided only on the heat dissipation portion 18 (lower surface 13) of the case outer surface 11. That is, a large number of protrusions 19t and recesses 19v are not present on the upper surface 12, the first wide side surface 14, the second wide side surface 15, the first narrow side surface 16, and the second narrow side surface 17. Therefore, the specific surface area Sc of the upper surface 12, the first wide side surface 14, the second wide side surface 15, the first narrow side surface 16, and the second narrow side surface 17 is the same as the specific surface area Sa of the area-increased portion 19 before the area-increasing process (Sc=Sa). In this embodiment, the area increasing process is performed by metal spraying, but the area increasing process is not limited to this, and may be performed by other physical or chemical surface roughening processes or surface roughening process in which nano-order projections and recesses are formed by irradiating a pulsed laser beam. In the surface roughening process by irradiating a pulsed laser beam, the specific surface area Sb after the process can be particularly large, specifically about 20 times, compared with the specific surface area Sa before the process.

[0025] Next, the case inner surface 21 exposed to the inside of the case 10 will be described in detail. The case inner surface 21 has an inner upper surface 22, an inner lower surface 23, a first inner wide side surface 24, a second inner wide side surface 25, a first inner narrow side surface 26, and a second inner narrow side surface 27, each of which has a rectangular shape. The inner upper surface 22 is located on the upper side AH1, and the inner lower surface 23 is located on the lower side AH2. The first inner wide side surface 24 and the second inner wide side surface 25 have a larger dimension in a direction perpendicular to the battery height direction AH (battery width direction BH or battery thickness direction CH) and a larger area than the first inner narrow side surface 26 and the second inner narrow side surface 27. The first inner wide side surface 24 is located on one side CH1 of the battery thickness direction CH, and the second inner wide side surface 25 is located on the other side CH2 of the battery thickness direction CH. The first inner narrow side surface 26 is located on one side BH1 in the battery width direction BH, and the second inner narrow side surface 27 is located on the other side BH2 in the battery width direction BH.

[0026] The case inner surface 21 includes a pair of electrode contact portions 28A, 28B that indirectly contact the electrode body 40 via the insulating holder 7 (that clamp and press the electrode body 40 covered by the insulating holder 7 in the battery thickness direction CH). One electrode contact portion 28A is a rectangular central portion of the first inner wide side surface 24 of the case inner surface 21 excluding its peripheral portion, and the other electrode contact portion 28B is a rectangular central portion of the second inner wide side surface 25 of the case inner surface 21 excluding its peripheral portion.

[0027] The entire case inner surface 21 including these electrode contact parts 28A, 28B is not subjected to the area increase treatment, unlike the area increase part 19 of the case outer surface 11, and does not have many convex parts 19t and concave parts 19v. Therefore, the specific surface area Sd of the electrode contact parts 28A, 28B of the case inner surface 21 is the same as the specific surface area Sc of the part of the case outer surface 11 other than the area increase part 19 (lower surface 13) and the specific surface area Sa of the area increase part 19 before the area increase treatment (Sd = Sc = Sa). Therefore, in this embodiment, the specific surface area Sb of the area increase part 19 of the case outer surface 11 is about 5 times larger than the specific surface area Sd of the electrode contact parts 28A, 28B of the case inner surface 21 (Sb / Sd is about 5). It is preferable that the specific surface area Sb of the area increase part 19 is about 3 to 20 times larger than the specific surface area Sd of the electrode contact parts 28A, 28B.

[0028] In the above-described battery 1, the heat dissipation portion 18 of the case outer surface 11 includes an area-increasing portion 19 in which a large number of protrusions 19t and recesses 19v are formed by the area-increasing treatment, and the specific surface area Sb is increased compared to the specific surface area Sa before the treatment. Therefore, the heat dissipation portion 18 of the battery 1 and the thermal conductive member 140 described below can be in contact with each other over a larger contact area Sn than when the heat dissipation portion 18 does not have the area-increasing portion 19. This allows for better thermal conduction from the heat dissipation portion 18 of the battery 1 to the thermal conductive member 140 than when the heat dissipation portion 18 does not have the area-increasing portion 19.

[0029] Furthermore, in this embodiment, the electrode contact portions 28A, 28B of the case inner surface 21 are in close contact with the electrode body 40, so that even if the specific surface area Sd of the electrode contact portions 28A, 28B is small, the heat of the electrode body 40 can be appropriately transferred to the case 10. On the other hand, because there may be variation in the gap between the heat dissipation section 18 of the case outer surface 11 and the cooling surface 130m of the cooler 130 described below due to variation in the attitude (tilt) of the battery 1, the ease with which heat is transferred (ease of heat dissipation) from the case 10 to the heat conductive member 140 tends to fluctuate, and this tends to become a barrier to heat dissipation. Therefore, it is preferable to increase the specific surface area Sb of the area increasing portion 19 of the case outer surface 11 compared to the specific surface area Sd of the electrode contacting portions 28A, 28B of the case inner surface 21, and to increase the contact area Sn between the heat dissipation section 18 of the case outer surface 11 and the heat conductive member 140, thereby improving the thermal conduction from the heat dissipation section 18 to the heat conductive member 140.

[0030] Furthermore, in this embodiment, the area increasing treatment is applied only to the heat dissipation portion 18 of the case outer surface 11. Since there is no need to apply the area increasing treatment to portions of the case outer surface 11 other than the heat dissipation portion 18, it is possible to provide an inexpensive battery 1 while ensuring heat dissipation from the battery 1 to the thermally conductive member 140.

[0031] Next, a battery pack 100 including a plurality of the above batteries 1 will be described (see Figs. 4 and 5). The battery pack 100 includes a pack case 110, a battery module 120 that is housed in the pack case 110 and includes a plurality of batteries 1, and a cooler 130 that is housed in the pack case 110 and cools each of the batteries 1 that constitute the battery module 120. A thermally conductive member 140 is disposed between each battery 1 of the battery module 120 and the cooler 130.

[0032] Of these, the pack case 110 is made of aluminum. The pack case 110 has a lower case 111 that houses the battery module 120, the cooler 130, and the heat conductive member 140 therein, and an upper case 112 that is located above the lower case 111 and fixed to the lower case 111.

[0033] The battery module 120 is housed in the pack case 110 in such a position that the battery height direction AH of each battery 1 coincides with the vertical direction DH of the battery pack 100, the battery width direction BH of each battery 1 coincides with the horizontal direction EH of the battery pack 100, and the battery thickness direction CH of each battery 1 coincides with the arrangement direction FH of the battery pack 100. In this battery module 120, multiple batteries 1 and multiple intervening members 122 are alternately stacked, and a pair of end plates 123 are arranged on both sides of the stacking direction (arrangement direction FH). These are restrained and integrated in a state where they are pressed in the arrangement direction FH by multiple restraining members 124 that span between the end plates 123. The positive electrode terminals 50 and negative electrode terminals 60 of the batteries 1 adjacent to each other in the arrangement direction FH are electrically connected via bus bars (conductive connection members) 125, and the batteries 1 constituting the battery module 120 are connected in series. The bus bar 125 is joined to the positive electrode terminal 50 and the negative electrode terminal 60 by welding.

[0034] The interposing member 122 is a rectangular plate made of an insulating elastic body (ethylene propylene diene rubber (EPDM) in this embodiment). The interposing member 122 is interposed between adjacent batteries 1 and is in contact with the first wide side surface 14 and the second wide side surface 15 of the adjacent batteries 1. The interposing member 122 is also interposed between the battery 1 and a pair of end plates 123. The end plate 123 is provided with a plurality of fixing parts (not shown) for fixing the battery module 120 to the lower case 111, and is fixed to the lower case 111 together with the cooler 130 using bolts and nuts (not shown). In this way, the cooler 130 is fixed between the battery module 120 and the lower case 111, and the lower surface 13 (heat dissipation part 18) of each battery 1 of the battery module 120 faces the cooling surface 130m of the cooler 130 via the thermally conductive member 140.

[0035] The cooler 130 is made of aluminum, has a rectangular plate shape extending in the row arrangement direction FH, and has a flow passage 131 formed therein, which extends in the row arrangement direction FH. A cooling medium RB (a cooling medium for an in-vehicle air conditioner in this embodiment) flows through the flow passage 131. A rectangular plate-shaped heat conduction member 140 having a first main surface 140a and a second main surface 140b is arranged on the cooling surface 130m, which is the upper surface of the cooler 130, and the heat conduction member 140 is in contact with the cooling surface 130m of the cooler 130 over the entire surface of the second main surface 140b. The cooler 130 is provided with multiple fixing parts (not shown) for fixing the cooler 130 to the lower case 111, and is fixed to the lower case 111 together with the battery module 120 using bolts and nuts (not shown) as described above.

[0036] The thermally conductive member 140 is interposed between the underside 13 (heat dissipation section 18) of each battery 1 in the battery module 120 and the cooling surface 130m of the cooler 130, with one first main surface 140a facing the battery module 120 (facing the upper side AH1) and the other second main surface 140b facing the cooler 130 (facing the lower side AH2). The thermally conductive member 140 is a member that transfers heat from the battery 1 to the cooler 130, and specifically, in this embodiment, a thermally conductive gel sheet is used.

[0037] By fixing the battery module 120 and the cooler 130 to the lower case 111 as described above, the heat conductive member 140 is compressed in the thickness direction (vertical direction DH, battery height direction AH) between the lower surface 13 (heat dissipation section 18) of each battery 1 and the cooling surface 130m of the cooler 130. A large number of protrusions 19t formed in the heat dissipation section 18 (area increase section 19) bite into the heat conductive member 140, and the heat conductive member 140 bites into a large number of recesses 19v formed in the area increase section 19, thereby increasing the contact area Sn between the heat dissipation section 18 and the heat conductive member 140. In this embodiment, the specific surface area Sb of the area increase section 19 is about five times larger than the specific surface area Sa before the area increase process, so that the contact area Sn between the heat dissipation section 18, the entire area of ​​which is the area increase section 19, and the heat conductive member 140 is also about five times larger than when the heat dissipation section 18 does not have the area increase section 19. It is particularly preferable that the contact area Sn between the heat dissipation portion 18 and the heat conductive member 140 is about 3 to 20 times larger than when the heat dissipation portion 18 does not have the area increasing portion 19. The size of the contact area Sn between the heat dissipation portion 18 of the battery 1 and the heat conductive member 140 can be determined, for example, by observing a cross section of the contact portion between the heat dissipation portion 18 and the heat conductive member 140 under an optical microscope.

[0038] In the battery pack 100 of this embodiment, the numerous protrusions 19t formed in the area increasing portion 19 bite into the heat conductive member 140, and the heat conductive member 140 bites into the numerous recesses 19v formed in the area increasing portion 19, thereby increasing the contact area Sn between the heat dissipation portion 18 of each battery 1 and the heat conductive member 140. This improves the thermal conduction from the heat dissipation portion 18 of each battery 1 to the heat conductive member 140, and allows each battery 1 to be appropriately cooled.

[0039] Although the present invention has been described above with reference to an embodiment, it goes without saying that the present invention is not limited to the embodiment and can be modified as appropriate without departing from the spirit of the present invention. For example, in the embodiment, the battery pack 100 in which a plurality of batteries 1 are stacked in a row has been exemplified, but a battery pack in which a plurality of batteries 1 are stacked in a plurality of rows may also be used. Furthermore, in the embodiment, the multiple batteries 1 included in the battery pack 100 are connected in series, but the electrical connection of the batteries 1 is not limited to this, and the batteries 1 may be connected in parallel. [Explanation of symbols]

[0040] 1. Battery (energy storage device) 7 Insulating holder 10 Cases 11 Case outer surface 18 Heat dissipation part 19 Area increase section 19t convex part 19v recess 21 Case inner surface 28A, 28B Electrode contact area 40 Electrode body 100 Battery pack (electricity storage device cooling structure) 120 Battery Module 130 Cooler 130m cooling surface 140 Thermally conductive materials (thermal conductive materials) Sa (specific surface area of ​​the area-increased part before area-increasing treatment) Sb Specific surface area (of the area-increased part after area-increasing treatment) Sc (specific surface area of ​​the outer surface of the case, excluding the area-increased portion) Sd (specific surface area of ​​the case inner surface) Sn Contact area (between the heat dissipation part of the battery and the thermal conductive material)

Claims

1. The device includes an electrode body and a metal case that houses the electrode body. the case has an outer surface exposed to the outside, The outer surface of the case includes a heat dissipation portion that faces a cooling surface of a cooler and dissipates heat toward the cooling surface via a thermally conductive material. An electricity storage device, The heat dissipation portion on the outer surface of the case is The area-increasing portion includes a surface area-increasing treatment that increases the specific surface area by forming a large number of protrusions and recesses. Energy storage device.

2. The power storage device according to claim 1 , The case has an inner surface exposed to the inside, the inner surface of the case includes an electrode contact portion that directly or indirectly contacts the electrode body, The specific surface area of ​​the area-increasing portion of the outer surface of the case is made larger than the specific surface area of ​​the electrode contact portion of the inner surface of the case. Energy storage device.

3. The electricity storage device according to claim 1 or 2, The area increasing treatment is applied only to the heat dissipation portion of the outer surface of the case. Energy storage device.

4. The electricity storage device according to claim 1 or 2; The cooler; the thermal conductive material being interposed between the heat dissipation portion of the power storage device and the cooling surface of the cooler. A cooling structure for an electricity storage device, A large number of the protrusions of the area increasing portion bite into the thermal conductive material, and the thermal conductive material bites into a large number of the recesses of the area increasing portion, thereby increasing the contact area between the heat dissipation portion of the power storage device and the thermal conductive material. Cooling structure for power storage devices.

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