Power storage device and power storage device cooling structure

Abstract

The present invention relates to a power storage device and a power storage device cooling structure provided with the power storage device. The power storage device includes, on an outer surface of a housing, a heat dissipation part that faces a cooling surface of a cooler and dissipates heat toward the cooling surface via a heat transfer member. The heat conduction from the housing of the power storage device to the heat conduction member can be improved. A battery (1) is provided with an electrode body (40) and a metal case (10) that accommodates the electrode body (40), the case (10) has a case outer surface (11) exposed to the outside, and the case outer surface (11) includes a heat dissipation part (18) that faces a cooling surface (130m) of a cooler (130) and dissipates heat toward the cooling surface (130m) via a heat transfer member (140). The heat dissipation part (18) of the housing outer surface (11) is provided with an area increasing part (19) which has been subjected to area increasing processing in which a plurality of convex parts (19t) and concave parts (19v) are formed to increase the specific surface area (Sb).

Description

Technical Field

[0001] The present invention relates to an electric storage device including a heat dissipation portion on an outer surface of a casing that faces a cooling surface of a cooler and dissipates heat toward the cooling surface via a heat conduction member, and an electric storage device cooling structure including the electric storage device. Background Art

[0002] In the past, there is a known battery pack including a battery, a cooler for cooling the battery, and a heat-conducting component (heat-conducting grease, heat-conducting sheet, etc.) disposed between the two and transferring heat from the battery to the cooler. As a related prior art, for example, Patent Document 1 (see Patent Document 1) can be cited. Figure 2 wait).

[0003] Patent Document 1: Japanese Patent Application Publication No. 2023-046725

[0004] However, in conventional battery packs, heat transfer from the battery casing to the heat transfer member is insufficient, making it difficult to appropriately cool the battery. Summary of the invention

[0005] The present invention has been made in view of the current situation, and provides an electric storage device capable of improving heat conduction from a casing of the electric storage device to a heat transfer member, and an electric storage device cooling structure including the electric storage device.

[0006] (1) One embodiment of the present invention for solving the above-mentioned problems is an electrical storage device, comprising an electrode body and a metal casing for accommodating the electrode body, the casing having an outer casing surface exposed to the outside, the outer casing surface including a heat dissipation portion, the heat dissipation portion being opposite to a cooling surface of a cooler and dissipating heat of the electrode body toward the cooling surface via a heat conductive component, wherein the heat dissipation portion of the outer casing surface includes an area increasing portion, the area increasing portion being subjected to an area increasing treatment for increasing a specific surface area by forming a plurality of convex portions and concave portions.

[0007] In the above-mentioned power storage device, the heat dissipation part of the outer surface of the shell of the power storage device includes an area increase part, and the area increase part is processed by area increase to form a plurality of convex parts and concave parts, and the specific surface area is increased compared with the specific surface area before the process. Therefore, compared with the case where the heat dissipation part does not have the area increase part, the heat dissipation part of the power storage device and the heat conduction component can be brought into contact with each other with a larger contact area. Thus, compared with the case where the heat dissipation part does not have the area increase part, the heat conduction from the heat dissipation part of the power storage device to the heat conduction component can be improved.

[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.

[0009] Examples of the “area increasing treatment” include physical surface roughening treatments such as shot blasting, sand blasting, and metal spraying, chemical surface roughening treatments such as anodizing and chemical etching, and surface roughening treatments to form nanoscale convex and concave portions by irradiation with a pulsed laser. Alternatively, the area increasing treatment may be to form an area increasing portion having a plurality of convex and concave portions by stamping.

[0010] In addition, the area increase portion may be formed only on a portion of the heat dissipation portion of the outer surface of the housing, or may be formed on the entire heat dissipation portion. In addition, a plurality of convex portions and concave portions similar to the plurality of convex portions and concave portions of the area increase portion may be formed on a portion other than the heat dissipation portion of the outer surface of the housing.

[0011] Examples of the “heat-conducting member” include heat-conducting grease applied in a layered form, a heat-conducting film, and a heat-conducting resin plate obtained by applying a liquid resin material in a layered form and then curing the liquid resin material.

[0012] Examples of the “cooler” include a cooler having a cooling path (flow path) inside and allowing a cooling medium such as cooling air or cooling liquid to flow therethrough.

[0013] (2) It can also be constructed as follows: based on the power storage device described in (1), the above-mentioned shell has an inner surface of the shell exposed inside, the above-mentioned shell inner surface includes an electrode close contact portion directly or indirectly close contact with the above-mentioned electrode body, and the above-mentioned specific surface area of ​​the above-mentioned area increase portion of the above-mentioned shell outer surface is greater than the specific surface area of ​​the above-mentioned electrode close contact portion of the above-mentioned shell inner surface.

[0014] In the above-described electrical storage device, the electrode close contact portion on the inner surface of the case is in close contact with the electrode body. Therefore, even if the specific surface area of ​​the electrode close contact portion is small, the heat of the electrode body can be appropriately conducted to the case.

[0015] On the other hand, when one or more of the power storage devices are used to form a power storage device cooling structure having a cooler and a heat-conducting component, the posture (tilt) of the power storage device may deviate between the power storage device cooling structures or between the multiple power storage devices included in the power storage device cooling structure. Moreover, as a result, the gap between the heat dissipation portion on the outer surface of the housing and the cooling surface of the cooler may deviate, so the ease of heat conduction from the housing to the heat-conducting component (the ease of heat dissipation) is prone to change, which is likely to become an obstacle to heat diffusion. Therefore, it is preferred to increase the specific surface area of ​​the area increase portion of the outer surface of the housing compared to the specific surface area of ​​the electrode close contact portion on the inner surface of the housing, so as to increase the contact area between the heat dissipation portion on the outer surface of the housing and the heat-conducting component, thereby improving the heat conduction from the heat dissipation portion to the heat-conducting component.

[0016] (3) In the electric storage device described in (1) or (2), the area increasing process may be performed only on at least a portion of the heat dissipation portion on the outer surface of the casing.

[0017] In the above-described power storage device, the area of ​​the outer surface of the casing other than the heat dissipation portion need not be increased, so that heat dissipation from the power storage device to the heat transfer member can be ensured and the power storage device can be made inexpensive.

[0018] (4) Another embodiment is a cooling structure for an electrical storage device, comprising the electrical storage device described in any one of (1) to (3), the cooler, and the heat conductive component interposed between the heat dissipation portion of the electrical storage device and the cooling surface of the cooler, wherein the plurality of protrusions of the area increasing portion are embedded in the heat conductive component, and the heat conductive component is embedded in the plurality of recesses of the area increasing portion, thereby increasing the contact area between the heat dissipation portion of the electrical storage device and the heat conductive component.

[0019] In the above-mentioned storage device cooling body, the plurality of convex portions formed on the area increase portion are embedded in the heat conduction component, and the heat conduction component is embedded in the plurality of concave portions formed on the area increase portion, so that the contact area between the heat dissipation portion of the storage device and the heat conduction component is increased. Therefore, the heat conduction from the heat dissipation portion of the storage device to the heat conduction component can be improved, so that the storage device can be appropriately cooled. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a perspective view of a battery according to an embodiment.

[0021] Figure 2 It is a bottom view of the battery according to the embodiment.

[0022] Figure 3 It is a cross-sectional view of the battery according to the embodiment along the battery height direction and the battery thickness direction.

[0023] Figure 4 It is a partial cross-sectional view along the longitudinal direction and the arrangement direction of the battery pack according to the embodiment.

[0024] Figure 5 The battery pack according to the embodiment Figure 4 An enlarged cross-sectional view showing the A portion in FIG.

[0025] Description of Reference Numerals

[0026] 1…battery (electrical storage device); 7…insulating retainer; 10…housing; 11…housing outer surface; 18…heat dissipation portion; 19…area increase portion; 19t…convex portion; 19v…concave portion; 21…housing inner surface; 28A, 28B…electrode close contact portion; 40…electrode body; 100…battery pack (electrical storage device cooling structure); 120…battery module; 130…cooler; 130m…cooling surface; 140…heat conductive component (heat conductive component); Sa…specific surface area (of the area increase portion before area increase treatment); Sb…specific surface area (of the area increase portion after area increase treatment); Sc…specific surface area (of the portion other than the area increase portion in the housing outer surface); Sd…specific surface area (of the housing inner surface); Sn…contact area (between the heat dissipation portion of the battery and the heat conductive component). DETAILED DESCRIPTION

[0027] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Figure 1 A perspective view of a battery (an example of an electric storage device of the present invention) 1 according to the present embodiment is shown in FIG. Figure 2 A bottom view of the battery 1 is shown in FIG. Figure 3 A cross-sectional view of the battery 1 along the battery height direction and the battery thickness direction is shown in FIG. Figure 4 A partial cross-sectional view of a battery pack (an example of a cooling structure for an electrical storage device of the present invention) 100 is shown in FIG. Figure 5 The battery pack 100 is shown in FIG. Figure 4 In addition, the battery height direction AH, the battery width direction BH, and the battery thickness direction CH of the battery 1 are defined as follows: Figure 1 to Figure 3 The longitudinal direction DH, transverse direction EH and arrangement direction FH of the battery pack 100 are defined as Figure 4-5 The directions shown are used for illustration.

[0028] The battery pack 100 is mounted on a hybrid vehicle, a plug-in hybrid vehicle, an electric vehicle, or the like. The battery pack 100 includes a plurality of batteries 1. The battery 1 is a rectangular (rectangular) sealed lithium-ion secondary battery, and is composed of a housing 10, an electrode body 40 and an electrolyte 5 contained in the housing 10, and a positive terminal 50 and a negative terminal 60 supported by the housing 10 (see Figure 1 to Figure 3 ) The electrode body 40 is covered by a bag-shaped insulating holder 7 which is made of an insulating film and is open at the upper side AH1 in the battery height direction AH.

[0029] The housing 10 is a cubic box made of metal (in this embodiment, aluminum), and is composed of a housing main body 31 that is a bottomed square tube with a rectangular opening 31c and accommodates the electrode body 40 inside, and a rectangular plate-shaped housing cover member 32 that blocks the opening 31c of the housing main body 31. The opening 31c of the housing main body 31 and the peripheral portion 32f of the housing cover member 32 are welded airtightly throughout the entire circumference. The housing cover member 32 is provided with a safety valve 35 that ruptures and opens the valve when the internal pressure of the housing 10 exceeds the valve opening pressure. In addition, the housing cover member 32 is provided with a liquid injection hole 32k, and the liquid injection hole 32k is airtightly sealed with a circular plate-shaped sealing member 36 made of aluminum.

[0030] In addition, rectangular insertion holes (not shown) are provided near the ends of one side BH1 and the other side BH2 in the battery width direction BH of the outer shell cover member 32. A positive electrode terminal 50 made of aluminum is inserted into the insertion hole of one side BH1, and the positive electrode terminal 50 is fixed to the outer shell cover member 32 in a state of being insulated from the outer shell cover member 32 via a resin member 55. The positive electrode terminal 50 is welded to the positive electrode collector 40c of the electrode body 40 described later in the outer shell 10, and is conductively connected to the positive electrode collector 40c. In addition, a negative electrode terminal 60 made of copper is inserted into the insertion hole of the other side BH2, and the negative electrode terminal 60 is fixed to the outer shell cover member 32 in a state of being insulated from the outer shell cover member 32 via a resin member 65. The negative electrode terminal 60 is welded to the negative electrode collector 40d of the electrode body 40 described later in the outer shell 10, and is conductively connected to the negative electrode collector 40d.

[0031] The electrode body 40 is a rectangular parallelepiped and a stacked type, and a plurality of rectangular positive plates 41 and a plurality of rectangular negative plates 42 are alternately stacked in the battery thickness direction CH via a rectangular separator 43 composed of a porous film made of resin. On one side BH1 of the battery width direction BH in the electrode body 40, the collector foils of each positive plate 41 overlap in the battery thickness direction CH to form a positive electrode collector 40c. The positive electrode collector 40c is connected to the positive terminal 50. In addition, on the other side BH2 of the battery width direction BH in the electrode body 40, the collector foils of each negative plate 42 overlap in the battery thickness direction CH to form a negative electrode collector 40d. The negative electrode collector 40d is connected to the negative terminal 60.

[0032] Next, the outer surface 11 of the outer shell 10 exposed outside the outer shell 10 (i.e., facing the outside of the outer shell 10) is described in detail. The outer surface 11 of the outer shell 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 is formed in a rectangular shape. The upper surface 12 is located on the upper side AH1, and the lower surface 13 is located on the lower side AH2. For 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, the dimensions in the battery height direction AH are the same, but the dimensions of the first wide side surface 14 and the second wide side surface 15 in the direction orthogonal to the battery height direction AH (battery width direction BH or battery thickness direction CH) are larger than those of the first narrow side surface 16 and the second narrow side surface 17, so the areas of the first wide side surface 14 and the second wide side surface 15 are larger than those of the first narrow side surface 16 and the second narrow side surface 17. The first wide side 14 is located on one side CH1 in the battery thickness direction CH, and the second wide side 15 is located on the other side CH2 in the battery thickness direction CH. In addition, the first narrow side 16 is located on one side BH1 in the battery width direction BH, and the second narrow side 17 is located on the other side BH2 in the battery width direction BH.

[0033] The outer surface 11 of the housing includes a heat dissipation portion 18, and the heat dissipation portion 18 is connected to a cooler 130 (see Figure 4 and Figure 5 ) is opposite to the cooling surface 130m, and heat is dissipated toward the cooling surface 130m via a heat conducting component (an example of the heat conducting component of the present invention) 140. In the present embodiment, the entire lower surface 13 of the outer surface 11 of the housing corresponds to the heat dissipation portion 18. The heat dissipation portion 18 (lower surface 13) includes an area increasing portion 19, and the area increasing portion 19 is formed by performing an area increasing treatment (in the present embodiment, metal spraying) on ​​at least a portion of the heat dissipation portion 18 to form a plurality of convex portions 19t and concave portions 19v (in Figure 2 Indicated by dots in the figure, the specific surface area Sb after the treatment is increased compared to the specific surface area Sa before the treatment. In the present embodiment, the entire heat dissipation portion 18 becomes the area increase portion 19. Preferably, the specific surface area Sb of the area increase portion 19 is about 3 to 20 times the specific surface area Sa before the area increase treatment, and in the present embodiment, it is about 5 times as large (Sb / Sa is about 5). In addition, the BET specific surface area is measured by a gas adsorption method using Kr gas, thereby obtaining the specific surface areas Sa and Sb.

[0034] In the present embodiment, the above-mentioned area increase portion 19 is provided only on the heat dissipation portion 18 (lower surface 13) in the outer surface 11 of the housing. That is, the plurality of convex portions 19t and concave portions 19v do not exist 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 increase portion 19 before the area increase process (Sc=Sa).

[0035] In addition, in the present embodiment, metal spraying is performed as the area increasing treatment, but the present invention is not limited thereto, and other physical or chemical surface roughening treatments or surface roughening treatments for forming nano-scale convex and concave portions by irradiation of pulsed laser may also be performed as the area increasing treatment. In the surface roughening treatment based on irradiation of pulsed laser, the specific surface area Sb after the treatment can be made particularly large, specifically, about 20 times, compared with the specific surface area Sa before the treatment.

[0036] Next, the shell inner surface 21 of the shell 10 exposed inside the shell 10 (i.e., facing the inner side of the shell 10) is described in detail. The shell 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 is formed in 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. For the first inner wide side surface 24 and the second inner wide side surface 25, the size in the direction orthogonal to the battery height direction AH (battery width direction BH or battery thickness direction CH) is larger than that of the first inner narrow side surface 26 and the second inner narrow side surface 27, and the area is larger. 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. In addition, 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.

[0037] The outer shell inner surface 21 includes a pair of electrode close contact portions 28A and 28B that are in indirect close contact with the electrode body 40 via the insulating holder 7 (the electrode body 40 covered by the insulating holder 7 is clamped and pressed in the battery thickness direction CH). One electrode close contact portion 28A is a rectangular central portion of the first inner wide side surface 24 of the outer shell inner surface 21 excluding its peripheral portion, and the other electrode close contact portion 28B is a rectangular central portion of the second inner wide side surface 25 of the outer shell inner surface 21 excluding its peripheral portion.

[0038] Unlike the area increase portion 19 of the outer shell surface 11, the entire inner shell surface 21 including the electrode close contact portions 28A and 28B is not subjected to the area increase treatment, and there are no multiple protrusions 19t and recesses 19v. Therefore, the specific surface area Sd of the electrode close contact portions 28A and 28B of the inner shell surface 21 is the same as the specific surface area Sc of the portion other than the area increase portion 19 (lower surface 13) in the outer shell surface 11, and the specific surface area Sa of the area increase portion 19 before the area increase treatment (Sd=Sc=Sa). Therefore, in the present embodiment, the specific surface area Sb of the area increase portion 19 of the outer shell surface 11 is about 5 times larger than the specific surface area Sd of the electrode close contact portions 28A and 28B of the inner shell surface 21 (Sb / Sd is about 5). In addition, it is preferable that the specific surface area Sb of the area increase portion 19 is about 3 to 20 times larger than the specific surface area Sd of the electrode close contact portions 28A and 28B.

[0039] In the above-mentioned battery 1, the heat dissipation portion 18 of the outer surface 11 of the housing includes an area increase portion 19, and the area increase portion 19 is formed by an area increase process to form a plurality of convex portions 19t and concave portions 19v, and the specific surface area Sb is increased compared to the specific surface area Sa before the process. Therefore, compared with the case where the heat dissipation portion 18 does not have the area increase portion 19, the heat dissipation portion 18 of the battery 1 and the heat conduction member 140 described later can be brought into contact with a larger contact area Sn. Thus, compared with the case where the heat dissipation portion 18 does not have the area increase portion 19, the heat conduction from the heat dissipation portion 18 of the battery 1 to the heat conduction member 140 can be improved.

[0040] In the present embodiment, electrode close contact portions 28A and 28B of case inner surface 21 are in close contact with electrode body 40 . Therefore, even if specific surface area Sd of electrode close contact portions 28A and 28B is small, heat of electrode body 40 can be appropriately conducted to case 10 .

[0041] On the other hand, for example, when a battery pack 100 described later is constructed using a plurality of batteries 1, the gap between the heat dissipation portion 18 of the outer shell surface 11 of each battery 1 and the cooling surface 130m of the cooler 130 described later may vary due to the deviation of the posture (tilt) of the batteries 1 included in the battery pack 100, so that the ease of heat conduction (ease of heat dissipation) from the outer shell 10 to the heat conducting member 140 is likely to vary, which is likely to become an obstacle to heat diffusion. Therefore, it is preferable to increase the specific surface area Sb of the area increase portion 19 of the outer shell surface 11 compared to the specific surface area Sd of the electrode close contact portions 28A and 28B of the inner shell surface 21, so as to increase the contact area Sn between the heat dissipation portion 18 of the outer shell surface 11 and the heat conducting member 140, thereby improving the heat conduction from the heat dissipation portion 18 to the heat conducting member 140.

[0042] In addition, in this embodiment, the area increase process is performed only on the heat dissipation portion 18 in the outer surface 11 of the housing. It is not necessary to perform the area increase process on the portion other than the heat dissipation portion 18 in the outer surface 11 of the housing, so that the heat dissipation from the battery 1 to the heat conducting member 140 can be ensured while the price of the battery 1 can be low.

[0043] Next, a battery pack 100 including a plurality of the above-described batteries 1 will be described (see Figure 4-5 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 the batteries 1 that constitute the battery module 120. In addition, a heat conducting member 140 is disposed between the batteries 1 of the battery module 120 and the cooler 130.

[0044] The package case 110 is made of aluminum and includes a lower case 111 that accommodates the battery module 120 , the cooler 130 , and the heat conducting member 140 , and an upper case 112 that is located above the lower case 111 and fixed to the lower case 111 .

[0045] The battery module 120 is housed in the package case 110 in a posture in which the battery height direction AH of each battery 1 is consistent with the longitudinal direction DH of the battery pack 100, the battery width direction BH of each battery 1 is consistent with the transverse direction EH of the battery pack 100, and the battery thickness direction CH of each battery 1 is consistent with the arrangement direction FH of the battery pack 100. The battery module 120 alternately stacks a plurality of batteries 1 and a plurality of interposing components 122, and a pair of end plates 123 are arranged on both sides of the stacking direction (arrangement direction FH). These components are constrained and integrated in a state of being pressed along the arrangement direction FH by a plurality of restraining components 124 spanned between the end plates 123. In addition, the positive terminals 50 and the negative terminals 60 of the adjacent batteries 1 in the arrangement direction FH are electrically connected via bus bars (conductive connecting components) 125, respectively, and the batteries 1 constituting the battery module 120 are connected in series. The bus bar 125 is joined to the positive terminal 50 and the negative terminal 60 by welding.

[0046] The interposing member 122 is a rectangular plate made of an insulating elastic body (in this embodiment, ethylene propylene diene monomer (EPDM)). The interposing member 122 is interposed between adjacent batteries 1 and contacts the first wide side surface 14 or the second wide side surface 15 of the adjacent battery 1. In addition, the interposing member 122 is interposed between the battery 1 and a pair of end plates 123.

[0047] The end plate 123 is provided with a plurality of fixing portions (not shown) for fixing the battery module 120 to the lower housing 111, and is fixed to the lower housing 111 together with the cooler 130 using bolts and nuts (not shown). Thus, the cooler 130 is fixed between the battery module 120 and the lower housing 111, and the lower surface 13 (heat dissipation portion 18) of each battery 1 of the battery module 120 faces the cooling surface 130m of the cooler 130 via the heat conducting member 140.

[0048] The cooler 130 is made of aluminum and is in the shape of a rectangular plate extending in the arrangement direction FH. A flow path (cooling path) 131 extending in the arrangement direction FH is formed therein. The cooling medium RB (in this embodiment, the cooling medium of the vehicle air conditioner) flows in the flow path 131 .

[0049] A rectangular plate-shaped heat transfer member 140 having a first main surface 140a and a second main surface 140b is disposed on a cooling surface 130m as an upper surface of the cooler 130. The heat transfer member 140 is in contact with the cooling surface 130m of the cooler 130 over the entire second main surface 140b.

[0050] The cooler 130 is provided with a plurality of fixing portions (not shown) for fixing the cooler 130 to the lower housing 111 , and is fixed to the lower housing 111 together with the battery module 120 using bolts and nuts (not shown) as described above.

[0051] The heat-conducting member 140 is interposed between the lower surface 13 (heat dissipation portion 18) of each battery 1 of the battery module 120 and the cooling surface 130m of the cooler 130, with one first main surface 140a facing the battery module 120 (toward the upper side AH1) and the other second main surface 140b facing the cooler 130 (toward the lower side AH2). The heat-conducting member 140 is a member that conducts the heat of the battery 1 to the cooler 130, and specifically, in this embodiment, a heat-conducting film is used.

[0052] By fixing the battery module 120 and the cooler 130 to the lower housing 111 as described above, the heat-conducting member 140 is compressed in the thickness direction (longitudinal direction DH, battery height direction AH) between the lower surface 13 (heat-dissipating portion 18) of each battery 1 and the cooling surface 130m of the cooler 130. In addition, the plurality of protrusions 19t formed on the heat-dissipating portion 18 (area-increasing portion 19) are embedded in the heat-conducting member 140, and the heat-conducting member 140 is embedded in the plurality of recesses 19v formed on the area-increasing portion 19, thereby increasing the contact area Sn between the heat-dissipating portion 18 and the heat-conducting member 140. In the present embodiment, the specific surface area Sb of the area-increasing portion 19 is about 5 times greater than the specific surface area Sa before the area-increasing treatment. Therefore, compared with the case where the heat-dissipating portion 18 does not have the area-increasing portion 19, the contact area Sn between the heat-dissipating portion 18, which is the area-increasing portion 19 as a whole, and the heat-conducting member 140 is also increased by about 5 times. In particular, it is preferred that the contact area Sn between the heat dissipating portion 18 and the heat conducting member 140 be increased by approximately 3 to 20 times compared to a case where the heat dissipating portion 18 does not include the area increasing portion 19 .

[0053] The size of the contact area Sn between the heat dissipation portion 18 and the heat conduction member 140 of the battery 1 can be obtained by observing the cross section of the contact portion between the heat dissipation portion 18 and the heat conduction member 140 under an optical microscope, for example.

[0054] In the battery pack 100 of the present embodiment, the plurality of convex portions 19t formed on the area increasing portion 19 are embedded in the heat conducting member 140, and the heat conducting member 140 is embedded in the plurality of concave portions 19v formed on the area increasing portion 19, thereby increasing the contact area Sn between the heat dissipating portion 18 of each battery 1 and the heat conducting member 140. Therefore, the heat conduction from the heat dissipating portion 18 of each battery 1 to the heat conducting member 140 is improved, and each battery 1 can be appropriately cooled.

[0055] As mentioned above, although this invention was demonstrated based on embodiment, this invention is not limited to embodiment, It goes without saying that it can be applied with appropriate changes within the range which does not deviate from the summary.

[0056] For example, in the embodiment, the battery pack 100 is exemplified in which a plurality of batteries 1 are stacked in one row, but a battery pack in which a plurality of batteries 1 are stacked in a plurality of rows may be used.

[0057] In addition, in the embodiment, the plurality of batteries 1 included in the battery pack 100 are connected in series, but the electrical connection between the batteries 1 is not limited thereto, and the batteries 1 may be connected in parallel.

Claims

1. An electric storage device, The electric storage device includes an electrode body and a metal case accommodating the electrode body. The housing has a housing outer surface exposed to the outside, The outer surface of the housing includes a heat dissipation portion, which is opposite to the cooling surface of the cooler and dissipates the heat of the electrode body toward the cooling surface via the heat conductive component. in, The heat dissipation portion on the outer surface of the housing includes an area-increasing portion that is subjected to an area-increasing treatment in which a plurality of convex portions and concave portions are formed to increase a specific surface area.

2. The power storage device according to claim 1, wherein The housing has a housing inner surface exposed internally, The inner surface of the housing includes an electrode contact portion that is in direct or indirect contact with the electrode body. The specific surface area of ​​the area-increasing portion of the outer surface of the housing is greater than the specific surface area of ​​the electrode-contacting portion of the inner surface of the housing.

3. The power storage device according to claim 1 or 2, wherein: The area increasing process is performed only on at least a portion of the heat dissipation portion in the outer surface of the housing.

4. A cooling structure for an electrical storage device, The electrical storage device cooling structure comprises: The electrical storage device according to any one of claims 1 to 3; the cooler; and the heat conducting member interposed between the heat dissipating portion of the electrical storage device and the cooling surface of the cooler, in, The plurality of protrusions of the area-increasing portion are fitted into the heat-conducting member, and the heat-conducting member is fitted into the plurality of recesses of the area-increasing portion, thereby increasing the contact area between the heat dissipating portion of the power storage device and the heat-conducting member.

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