ENERGY STORAGE DEVICE AND ELECTRICALLY POWERED VEHICLE

Abstract

An energy storage device (10, 10A, 10B) comprises: a plurality of battery cells (100), each comprising a positive electrode terminal (101) and a negative electrode terminal (102), wherein the plurality of battery cells (100) are arranged adjacent to one another in a first axial direction; and a first cooler and a second cooler (13A to 13E, 14), wherein the first cooler and the second cooler (13A to 13E, 14) are each in contact with the individual battery cells (100) directly or with a heat-conducting element arranged therebetween. The first cooler (13A to 13E) is arranged above the second cooler (14), and the second cooler (14) is arranged below the individual positive electrode terminals (101) and the individual negative electrode terminals (102). The first cooler (13A to 13E) has a lower thermal conductivity than the second cooler (14).

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Patent Application No. 2024-019308 filed with the Japan Patent Office on February 13, 2024, the entire contents of which are incorporated herein by reference. BACKGROUND area

[0002] The present disclosure relates to an energy storage device and an electrically powered vehicle. Description of the state of the art

[0003] Conventionally, an energy storage device has been installed in an electric vehicle. For example, Japanese Patent Laid-Open No. 2023-165300 discloses, as an example of an energy storage device, a battery pack disposed under a floor panel of a vehicle. The battery pack disclosed in Japanese Patent Laid-Open No. 2023-165300 includes a plurality of battery modules and a battery case in which the plurality of battery modules are housed. The battery case includes a bottom plate forming a lower surface of the battery case. The bottom plate includes a cooling path through which a coolant flows. SUMMARY

[0004] When a battery cell is cooled from multiple surfaces, the surface area of ​​a cooler exposed to the outside is larger than when the battery cell is cooled from a single surface. This results in a larger amount of water droplets formed by condensation in the cooler. Thus, there is a need to prevent short circuits in the energy storage device.

[0005] The present disclosure provides an energy storage device capable of preventing a short circuit caused by water droplets formed by the formation of condensate in each of the radiators, even when a plurality of radiators are used; and an electric vehicle including the energy storage device.

[0006] According to one aspect of the present disclosure, an energy storage device comprises: a plurality of battery cells, each including a positive electrode terminal and a negative electrode terminal, the plurality of battery cells being arranged adjacent to each other in a first axial direction; and a first cooler and a second cooler, the first cooler and the second cooler each being in contact with the individual battery cells directly or with a heat-conducting member disposed therebetween. The first cooler is arranged above the second cooler, and the second cooler is arranged below the individual positive electrode terminals and the individual negative electrode terminals. The first cooler has a lower thermal conductivity than the second cooler.

[0007] According to the above-described configuration, the first cooler, which is arranged above the second cooler, has a lower thermal conductivity than the second cooler. Condensation is less likely to occur with lower thermal conductivity than with higher thermal conductivity. Thus, condensation is more likely to occur in the second cooler than in the first cooler. Furthermore, the second cooler is arranged below each positive electrode terminal and each negative electrode terminal. This prevents water droplets caused by condensation from adhering to the positive electrode terminal and the negative electrode terminal. Therefore, even when multiple coolers are used, a short circuit in the energy storage device caused by water droplets caused by condensation in the coolers can be prevented.

[0008] Preferably, the individual battery cells each have a first surface that serves as a bottom surface. The second cooler is arranged below the first surface and is in contact with the first surface directly or with the heat-conducting element arranged therebetween.

[0009] According to the configuration described above, the second cooler is arranged below each battery cell. Thus, even if water droplets generated by condensation in the second cooler fall down, the water droplets do not fall on the individual battery cells. This can prevent a short circuit between the terminals caused by water droplets formed in the second cooler.

[0010] Preferably, the first cooler is in contact with the individual positive electrode terminals and the individual negative electrode terminals directly or with the heat-conducting element arranged therebetween.

[0011] According to the configuration described above, each of the positive and negative electrode terminals that are more likely to generate heat in the battery cells can be cooled even when a high current is supplied to or discharged from each battery cell, and further, water droplets formed by condensation can be prevented from adhering to each of the positive and negative electrode terminals.

[0012] Preferably, the individual battery cells each further have a second surface serving as the upper surface. The positive electrode terminal and the negative electrode terminal protrude upward from the second surface.

[0013] According to the configuration described above, the first cooler can be installed on the side of the upper surface of each battery cell.

[0014] Preferably, the first axial direction is perpendicular to a vertical axial direction. The individual battery cells each have a first lateral surface and a second lateral surface, wherein the first lateral surface and the second lateral surface each have a normal direction in a second axial direction perpendicular to the first axial direction and the vertical axial direction. The positive electrode terminal protrudes from the first lateral surface in the second axial direction. The negative electrode terminal protrudes from the second lateral surface in the second axial direction.

[0015] According to the configuration described above, the distance between the positive electrode terminal and the negative electrode terminal in each battery cell can be larger than in the case where the positive electrode terminal and the negative electrode terminal protrude from the upper surface of each battery cell. Therefore, a short circuit between each positive electrode terminal and each negative electrode terminal included in the same battery cell due to water droplets formed during condensation can be prevented.

[0016] Preferably, the first cooler and the second cooler each serve as a cooling tube extending in the first axial direction and having a flow path for refrigerant. The first cooler and the second cooler each have an inner surface in contact with the refrigerant and an outer surface opposite the inner surface. The outer surface of the first cooler includes a first contact area in contact with the individual positive electrode terminals and the individual negative electrode terminals, directly or with the heat-conducting member interposed therebetween, and a first non-contact area excluding the first contact area from the outer surface.The outer surface of the second cooler includes a second contact area that is in contact with the individual battery cells directly or with the heat-conducting element arranged therebetween; and a second non-contact area, excluding the second contact area from the outer surface. The first non-contact area is smaller in area than the second non-contact area.

[0017] According to the above-described configuration, a portion of the outer surface of the first cooler that is in contact with the gas in the energy storage device is smaller in area than a portion of the outer surface of the second cooler that is in contact with the gas in the energy storage device. Therefore, compared to the case where the above-mentioned relationship in areas is not established, the formation of condensation can be more preferentially caused on the outer surface of the second cooler, while the formation of condensation on the outer surface of the first cooler is further prevented.

[0018] Preferably, the first cooler comprises a first portion and a second portion that are adjacent to each other in an outer circumferential direction of the first cooler, the first portion and the second portion each extending in the first axial direction. The first portion and the second portion form the flow path. At least one of the first portion and the second portion is provided with a groove portion that forms the flow path. At least a part of the first portion is in contact with the individual positive electrode terminals and the individual negative electrode terminals directly or with the heat-conducting member arranged therebetween. The second portion of the individual positive electrode terminals and the individual negative electrode terminals is farther away than the first portion.The first section has a higher thermal conductivity than the second section and a lower thermal conductivity than the second cooler.

[0019] According to the above-described configuration, the first portion, which is in contact with the individual positive electrode terminals and the individual negative electrode terminals with the heat-conducting member interposed therebetween, has a higher thermal conductivity than the second portion, which is not in contact with the heat-conducting member. Therefore, compared with the case where the thermal conductivity of the second portion is equal to or higher than the thermal conductivity of the first portion, the individual positive and negative electrode terminals can be efficiently cooled. Furthermore, the second cooler can prevent the formation of condensation water in the second portion of the first cooler.

[0020] Preferably, the first cooler is connected to a first tube on an upstream side and to a second tube on a downstream side. The first tube has a lower thermal conductivity than the second tube.

[0021] According to the configuration described above, the amount of water droplets formed by the formation of condensed water can be smaller in the first pipe on the upstream side of the first cooler than in the second pipe on the downstream side of the first cooler.

[0022] Preferably, the second cooler is connected to a third tube on the upstream side and to a fourth tube on the downstream side. The third tube is connected to the first tube. The fourth tube is connected to the second tube. The third tube has a lower thermal conductivity than the fourth tube.

[0023] According to the configuration described above, the amount of water droplets formed by condensation can be smaller in the third tube on the upstream side of the second cooler than in the fourth tube on the downstream side of the second cooler. Furthermore, the refrigerant can be directed from one path into two paths (the first tube and the third tube).

[0024] Furthermore, the refrigerant from two paths (the second pipe and the fourth pipe) can be combined into one path.

[0025] According to another aspect of the present disclosure, an electrically powered vehicle includes a plurality of battery cells, each including a positive electrode terminal and a negative electrode terminal, the plurality of battery cells being arranged adjacent to each other in a predetermined axial direction; and a first cooler and a second cooler, the first cooler and the second cooler each being in contact with the individual battery cells directly or with a heat-conducting member arranged therebetween. The first cooler is arranged above the second cooler. The second cooler is arranged below the individual positive electrode terminals and the individual negative electrode terminals. The first cooler has a lower thermal conductivity than the second cooler.

[0026] According to the configuration described above, condensation is more likely to occur in the second cooler than in the first cooler. Therefore, even when multiple coolers are used, a short circuit in the energy storage device due to water droplets formed by condensation in the cooler can be prevented.

[0027] The foregoing and other objects, features, aspects and advantages of the present disclosure will become more apparent from the following detailed description of the present disclosure when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a side view of an electric vehicle. Fig. 2 is a partial cross-sectional view of a battery pack. Fig. 3 is a top view of the battery pack. Fig. 4 is a bottom view of the battery pack. Fig. Figure 5 is a diagram illustrating a cooler. Fig. 6 is a cross-sectional view along an arrowed line VI-VI in Fig. 2. Fig. Figure 7 is a diagram showing an upper cooler made of Fig. 6 and its surroundings. Fig. Figure 8 is a diagram showing a lower radiator made of Fig. 6 and its surroundings. Fig. 9 is a diagram illustrating a modification of the cooler mounted over a battery module. Fig. 10 is a diagram illustrating another modification of the cooler mounted above the battery module. Fig. 11 is a diagram showing a battery pack according to another embodiment. Fig. Figure 12 is a diagram illustrating a modification of the battery pack. DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. In the embodiments described below, the same or corresponding portions in the drawings are denoted by the same reference numerals, and their descriptions will not be repeated. [First embodiment]

[0029] Fig. 1 is a side view of an electrically powered vehicle. As shown in Fig. As shown in Figure 1, an electrically powered vehicle 1 includes a vehicle body 2, a front wheel 3, a rear wheel 4, and a battery pack 10. The battery pack 10 is attached to a bottom portion of the vehicle body 2. The electrically powered vehicle 1 is, for example, a hybrid electric vehicle capable of running with the driving power of at least one of a motor and an internal combustion engine, or an electrically powered vehicle capable of running with driving power derived from electric power. The battery pack 10 and the battery packs 10A and 10B (described below) are each an example of the energy storage device of the present disclosure.

[0030] The configuration of the battery pack 10 is described below based on the state in which the battery pack 10 is attached to an electric vehicle 1. In other words, the axial direction and direction of the battery pack 10, such as up, down, left, right, up, and down, are defined with respect to the state in which the battery pack 10 is attached to the electric vehicle 1 (this state is also referred to as the "attached state" hereinafter).

[0031] In the following description, the vertical axis direction is referred to as "axis direction D3." The vertical upward direction is defined as "direction D31." The vertical downward direction is referred to as "direction D32."

[0032] Fig. 2 is a partial cross-sectional view of the battery pack 10. Fig. 3 is a top view of the battery pack 10. Fig. 4 is a bottom view of the battery pack 10. In the Fig. 3 and Fig. 4, an outer housing 11 described below is not shown for the sake of simplicity.

[0033] As it is in the Fig. 2 to 4, the tubes 5A, 5B, 6A, 6B, 7 and 8 are connected to the battery pack 10. Each of the tubes 5A, 5B, 6A, 6B, 7 and 8 is an external tube connected to the battery pack 10. Line-up arrows shown in each of the Fig. 2 to 4 indicate the direction of the flow of the refrigerant 900 ( Fig. 6), which is described below.

[0034] The pipes 5A, 5B, and 7 are connected to each other on the upstream side of the refrigerant 900. The pipes 6A, 6B, and 8 are connected to each other on the downstream side of the refrigerant 900. Thus, the refrigerant 900 that has flowed from the upstream side is branched to flow through the pipes 5A, 5B, and 7 on the upstream side of the battery pack 10 and then flows into the battery pack 10. Then, the refrigerants 900 flow through the pipes 6A, 6B, and 8. After that, the refrigerants 900 that flow through the pipes combine or mix with each other on the downstream side of the battery pack 10.

[0035] Tubes 5A and 5B have a lower thermal conductivity than tubes 6A and 6B. Tubes 7 have a lower thermal conductivity than tubes 8. In the present example, tubes 5A and 5B are made of the same material. Tubes 6A and 6B are made of the same material.

[0036] The battery pack 10 includes the outer housing 11, a battery module 12, coolers 13A, 13B, and 14, and connecting elements 18 and 19. The battery module 12 and the coolers 13A, 13B, and 14 are housed in the outer housing 11. The battery pack 10 may contain multiple battery modules 12.

[0037] The battery module 12 comprises a plurality of battery cells 100 and a plurality of bus bars 120. The plurality of battery cells 100 are arranged adjacent to one another in an axial direction D1. The battery cells 100 are arranged in a row. The axial direction D1 is perpendicular to the axial direction D3. The axial direction D1 corresponds, for example, to a front-rear direction of an electrically powered vehicle 1. Alternatively, the axial direction D1 corresponds to a vehicle width direction of an electrically powered vehicle 1. The axial direction D1 is not particularly limited as long as it is perpendicular to the axial direction D3.

[0038] As it is in Fig. As shown in Figure 3, each battery cell 100 has a positive electrode terminal 101 and a negative electrode terminal 102. The positive electrode terminal 101 and the negative electrode terminal 102 of the battery cell 100 are spaced apart from each other in an axial direction D2 perpendicular to the axial directions D1 and D3. The battery cells 100 are arranged such that positive electrode terminals 101 alternate with negative electrode terminals 102 along the axial direction D1.

[0039] In this way, the battery pack 10 has two electrode terminal rows, each extending along the axial direction D1 and spaced apart from each other along the axial direction D2. Each electrode terminal row includes a plurality of positive electrode terminals 101 and a plurality of negative electrode terminals 102. In each of the electrode terminal rows, positive electrode terminals 101 alternate with negative electrode terminals 102. The coolers 13A and 13B are arranged in contact with different electrode terminal rows with bus bars 120 and an adhesive layer 16 therebetween.

[0040] The positive electrode terminal 101 of the battery cell 100 is connected to the negative electrode terminal 102 of the adjacent battery cell 100 by the bus bar 120 in a direction D11 of the axial direction D1. The negative electrode terminal 102 of the battery cell 100 is connected to the positive electrode terminal 101 of the adjacent battery cell 100 via the bus bar 120 in a direction D12 of the axial direction D1. The bus bar 120 is attached to the positive electrode terminal 101 and the negative electrode terminal 102.

[0041] It should be noted that the "Direction D11" is directed in the same direction as indicated by the arrows described above. In other words, the direction D11 corresponds to the direction in which the refrigerant 900 ( Fig. 6), which is described below, flows through the battery pack 10. The "direction D12" is opposite to the direction D11.

[0042] As it is in Fig. 2, the radiator 13A is arranged above the radiator 14. The radiator 13A is fixed at a position higher than the position of the radiator 14. As shown in the Fig. 2 and Fig. 3, the cooler 13A extends along the axial direction D1. The cooler 13A is connected to the pipe 5A via the connecting member 18 on the upstream side of the refrigerant 900. The cooler 13A is connected to the pipe 6A via the connecting member 18 on the downstream side of the refrigerant 900.

[0043] Like the radiator 13A, the radiator 13B is arranged above the radiator 14. The radiator 13B is fixed at a position higher than the position of the radiator 14. As shown in Fig. As shown in Figure 3, the radiator 13B extends along the axial direction D1, just like the radiator 13A. The radiator 13B is arranged parallel to the radiator 13A at a position away from the radiator 13A along the axial direction D2. The radiator 13B is connected to the pipe 5B via the connecting member 18 on the upstream side of the refrigerant 900. The radiator 13B is connected to the pipe 6B via the connecting member 18 on the downstream side of the refrigerant 900.

[0044] As it is in the Fig. 2 and Fig. As shown in Figure 4, the radiator 14 extends along the axial direction D1, just like the radiators 13A and 13B. The radiator 14 is arranged parallel to the radiators 13A and 13B at a position away from the radiators 13A and 13B along the axial direction D3. The radiator 14 is connected to the pipe 7 via the connecting member 19 on the upstream side of the refrigerant 900. The radiator 14 is connected to the pipe 8 via the connecting member 19 on the downstream side of the refrigerant 900.

[0045] As it is in the Fig. 2 and Fig. 3, the coolers 13A and 13B are attached to the battery module 12 by means of an adhesive. The cooler 13A is attached to the top of the battery module 12 by means of an adhesive. In particular, the coolers 13A and 13B, as shown in Fig. 3, is attached to the plurality of bus bars 120 arranged in a line along the axial direction D1 by means of an adhesive. In particular, the coolers 13A and 13B, as shown in Fig. 2, the heat sinks 13A and 13B are attached to the busbars 120 with an adhesive layer 16 made of an adhesive. The adhesive layer 16 is insulating and heat-conductive. In the present example, the coolers 13A and 13B are attached to an upper surface of the individual busbars 120.

[0046] When each bus bar 120 is attached to each positive electrode terminal 101 and each negative electrode terminal 102 such that the tip ends of each positive electrode terminal 101 and each negative electrode terminal 102 are exposed, the coolers 13A and 13B can be brought into contact with these positive electrode terminals 101 and negative electrode terminals 102 arranged alternately along the axial direction D1 without the bus bars 120 being interposed therebetween. In other words, each of the coolers 13A and 13B can be brought into contact with the positive electrode terminals 101 and the negative electrode terminals 102 with only the adhesive layer of an adhesive agent interposed therebetween.Further, each of the coolers 13A and 13B may be in direct contact with the positive electrode terminals 101 and the negative electrode terminals 102 arranged alternately along the axial direction D1 without the bus bars 120 and the adhesive layer 16 being interposed therebetween.

[0047] As it is in the Fig. 2 and Fig. 3, the cooler 14 is attached to the battery module 12 by means of an adhesive. The cooler 14 is attached to the underside of the battery module 12 by means of the adhesive. In particular, the cooler 14, as shown in Fig. 4, is attached to the plurality of battery cells 100 arranged in a row along the axial direction D1 by means of an adhesive. In particular, the cooler 14, as shown in Fig. 2, the adhesive layer 17 is attached to the individual battery cells 100 by an adhesive layer 17 made of adhesive. The adhesive layer 17 is thermally conductive. In the present example, the adhesive forming the adhesive layer 17 is the same as the adhesive forming the adhesive layer 16. However, the present disclosure is not limited thereto.

[0048] Fig. 5 is a diagram illustrating the coolers 13A, 13B and 14. As shown in Fig. 5, the radiators 13A, 13B, and 14 are tubular. In other words, the radiators 13A, 13B, and 14 are each a cooling tube through which refrigerant 900 flows. In the present example, the radiators 13A, 13B, and 14 are each a polygonal tube. Specifically, the radiators 13A, 13B, and 14 are each a rectangular tube with a rectangular cross section. Note that the radiators 13A and 13B may each be a square tube with a square cross section.

[0049] According to such a configuration, a flow path 390A through which the refrigerant 900 flows is formed within the radiator 13A. A flow path 390B through which the refrigerant 900 flows is formed within the radiator 13B. A flow path 490 through which the refrigerant 900 flows is formed within the radiator 14. In the present example, the radiators 13A and 13B have the same configuration. The radiators 13A and 13B have the same shape and are made of the same material. However, the radiators 13A and 13B do not necessarily have to have the same shape; they may also have different shapes.

[0050] Each of the coolers 13A and 13B has an outer surface 310 and an inner surface 320. The inner surface 320 forms each of the flow paths 390A and 390B. The refrigerant 900 comes into contact with the inner surface 320.

[0051] The outer surface 310 includes an upper surface 311, a side surface 312, a lower surface 313, and a lateral surface 314. The upper surface 311, the side surface 312, the lower surface 313, and the lateral surface 314 are connected to each other in this order. The direction of the normal to the upper surface 311 and the direction of the normal to the lower surface 313 correspond to the axial direction D3. The direction of the normal to the side surface 312 and the direction of the normal to the side surface 314 correspond to the axial direction D2.

[0052] The adhesive layer 16 (see Fig. 2) exists between the lower surface 313 and the plurality of bus bars 120. The lower surface 313 is bonded to the upper surfaces of the plurality of bus bars 120 with the above-mentioned adhesive.

[0053] The cooler 14 has an inner surface 420 and an outer surface 410. The inner surface 420 forms the flow path 490. The refrigerant 900 comes into contact with the inner surface 420.

[0054] The outer surface 410 includes a top surface 411, a side surface 412, a bottom surface 413, and a side surface 414. The top surface 411, the side surface 412, the bottom surface 413, and the side surface 414 are connected to each other in this order. The direction of the normal to the top surface 411 and the direction of the normal to the bottom surface 413 correspond to the axial direction D3. The direction of the normal to the side surface 412 and the direction of the normal to the side surface 414 correspond to the axial direction D2.

[0055] The adhesive layer 17 (see Fig. 2) is located between the lower surface 413 and a bottom portion of the individual battery cells 100. The lower surface 413 is bonded to a lower surface of the individual battery cells 100 with the above-mentioned adhesive.

[0056] Fig. 6 is a cross-sectional view along an arrowed line VI-VI in Fig. 2. In particular, Fig. 6 is a cross-sectional view including: a central axis direction of the positive electrode terminal 101 extending along the axis direction D3; and a central axis direction of the negative electrode terminal 102 extending along the axis direction D3. As shown in Fig. 6, the battery cell 100 includes, in addition to the positive electrode terminal 101 and the negative electrode terminal 102 as described above, an outer casing 103, an electrode assembly 104, a positive electrode tab 105, and a negative electrode tab 106.

[0057] The outer casing 103 houses the electrode assembly 104, the positive electrode tab 105, and the negative electrode tab 106. In the present example, an electrolyte solution is enclosed in the outer casing 103. The electrode assembly 104 is, for example, a stacked electrode assembly in which the positive electrodes and the negative electrodes are alternately stacked with separators arranged therebetween.

[0058] The positive electrode tab 105 is connected to a positive electrode of the electrode assembly 104 and the positive electrode terminal 101. The negative electrode tab 106 is connected to a negative electrode of the electrode assembly 104 and the negative electrode terminal 102. When the electrode assembly 104 is a stacked electrode assembly, each of the positive electrode tab 105 and the negative electrode tab 106 consists of a plurality of current collecting foils.

[0059] The outer casing 103 includes a top surface 1031, a side surface 1032, a bottom surface 1033, and a side surface 1034. The top surface 1031, the side surface 1032, the bottom surface 1033, and the side surface 1034 are connected to each other in this order. The direction of the normal to the top surface 1031 and the direction of the normal to the bottom surface 1033 correspond to the axial direction D3. The direction of the normal to the side surface 1032 and the direction of the normal to the side surface 1034 correspond to the axial direction D2.

[0060] The side surfaces 1032 and 1034 are each part of the outer peripheral surface of the outer casing 103. The outer peripheral surface is also part of the outer peripheral surface of the battery cell 100. The outer peripheral surface is adjacent to the upper surface 1031 and the lower surface 1033. The outer peripheral surface includes four side surfaces. Of these four side surfaces, two side surfaces (not shown), except for the side surfaces 1032 and 1034, have a normal direction along the axial direction D1 and face each other with the electrode assembly 104 therebetween.

[0061] The positive electrode terminal 101 and the negative electrode terminal 102 protrude from the outer casing 103 in the direction D31. The positive electrode terminal 101 and the negative electrode terminal 102 protrude upward from the upper surface 1031.

[0062] In the present example, coolers 13A and 13B are arranged above the positive electrode terminal 101 and the negative electrode terminal 102. The cooler 14 is arranged below the positive electrode terminal 101 and the negative electrode terminal 102. Thus, the positive electrode terminal 101 and the negative electrode terminal 102 are arranged below the coolers 13A and 13B, and the cooler 14 is arranged below the positive electrode terminal 101 and the negative electrode terminal 102.

[0063] The bus bar 120 is arranged above the positive electrode terminal 101 and the negative electrode terminal 102. The coolers 13A and 13B are attached to an upper surface of the bus bar 120 using an adhesive. Thus, the adhesive layer 16 is located between the bus bar 120 and the coolers 13A and 13B. The cooler 14 is attached to the lower surface 1033 of the outer casing 103 using an adhesive. Thus, the adhesive layer 17 is located between the cooler 14 and the lower surface 1033. As described above, the refrigerant 900 flows through the coolers 13A, 13B, and 14.

[0064] As described above, in the state where at least the battery pack 10 is installed in the electric vehicle 1, the radiators 13A and 13B are arranged above the radiator 14. The radiators 13A and 13B are made of a different material than the radiator 14. The radiators 13A and 13B have a lower thermal conductivity than the radiator 14. The thermal conductivity of each of the radiators 13A, 13B, and 14 specifically refers to the thermal conductivity of a non-contact region (specifically, the non-contact regions Q1 and Q2 described below) in each of the radiators 13A, 13B, and 14.

[0065] In the present example, the coolers 13A and 13B are made of resin. The thermal conductivity of polyamide (6-nylon) (PA), as a type of resin, at 20°C is 0.25 W / (m·K). The cooler 14 is made of aluminum (Al). The thermal conductivity of aluminum at 27°C is 237.0 W / (m·K). The method for measuring the thermal conductivity is not particularly limited, and the thermal conductivity can be measured by known methods.

[0066] The material of the coolers 13A and 13B is not limited to resin. For example, the coolers 13A and 13B can be made of rubber. Similarly, the material of the cooler 14 is not limited to aluminum. For example, the cooler 14 can be made of other metals such as iron or stainless steel (SUS).

[0067] The thermal conductivity of natural rubber (with a density of 0.991 g / cm 3) as a type of rubber at 20°C is 0.13 W / (m·K). The thermal conductivity of iron at 27°C is 80.3 W / (m·K). The thermal conductivity of stainless steel (SUS304) at 27°C is 16.0 W / (m·K). The radiator 14 is preferably made of aluminum rather than iron and stainless steel in terms of thermal conductivity and weight.

[0068] Tin (Sn) and aluminum differ in their thermal conductivity by a maximum of four times. If the coolers 13A and 13B and the cooler 14 are each made of metal, the coolers 13A and 13B can be made of a metal with relatively low thermal conductivity, such as tin, and the cooler 14 can be made of a metal with relatively high thermal conductivity, such as aluminum.

[0069] The difference in thermal conductivity between the cooler 14 and each of the coolers 13A and 13B is preferably 50.0 W / (m·K) or more at a prescribed temperature. The difference in thermal conductivity at a prescribed temperature is preferably 200.0 W / (m·K) or more. The prescribed temperature is preferably an ambient temperature around the energy storage device. The prescribed temperature is preferably in a range of 5°C or higher and 80°C or lower, for example. The prescribed temperature may be in a range of 20°C or higher and 80°C or lower, and is more preferably in a range of 20°C or higher and 60°C or lower.

[0070] The outer surface 310 of the cooler 13A includes: a contact area (hereinafter also referred to as "contact area P1") in contact with the positive electrode terminal 101 and the negative electrode terminal 102m, with the adhesive layer 16 and the bus bar 120 therebetween; and a non-contact area (hereinafter also referred to as "non-contact area Q1") excluding the contact area P1 from the outer surface 310. The outer surface 310 of the cooler 13B also includes the contact area P1 and the non-contact area Q1.

[0071] The outer surface 410 of the cooler 14 includes: a contact region (hereinafter also referred to as "contact region P2") in contact with each battery cell 100 with the adhesive layer 17 interposed therebetween; and a non-contact region (hereinafter also referred to as "non-contact region Q2") excluding the contact region P2 from the outer surface 410.

[0072] The total of the area of ​​the non-contact area Q1 on the outer surface 310 of the cooler 13A and the area of ​​the non-contact area Q1 on the outer surface 310 of the cooler 13B is smaller than the area of ​​the non-contact area Q2 on the outer surface 310 of the cooler 14. In other words, the following equation (1) is satisfied. 2×Q1 <Q2

[0073] Fig. 7 is a diagram showing the cooler 13A in Fig. 6 and its surroundings. Fig. Figure 8 is a diagram showing the cooler 14 in Fig. 6 and its surroundings.

[0074] As it is in Fig. As shown in Figure 7, the length of the upper surface 311 along the axial direction D2 is defined as L11. The length of the side surface 312 along the axial direction D3 is defined as L12. Of the length of the lower surface 313 along the axial direction D2, the length of an outward-facing portion corresponds to the total value of L13a and L13b. Of the length of the lower surface 313 along the axial direction D2, the length of a portion not facing outward is defined as L13c. L13c corresponds to the diameter of the positive electrode terminal 101 or the negative electrode terminal 102. The length of the side surface 314 along the axial direction D3 is defined as L14. Note that L12 and L14 have the same value. The total of L13a, L13b, and L13c is equal to L11. The cooler 13B also has the same dimensions as the cooler 13A.

[0075] Of the length of the upper surface 411 along the axial direction D2, the length of an outwardly exposed portion is equal to the total value of L21a and L21b. Of the length of the upper surface 411 along the axial direction D2, the length of a portion not facing outward is defined as L21c. The length of the lateral surface 412 along the axial direction D3 is defined as L22. The length of the lower surface 413 along the axial direction D2 is defined as L23. The length of the lateral surface 414 along the axial direction D3 is defined as L24. L22 and L24 have the same value. The total of L21a, L21b, and L21c is equal to L23.

[0076] Similarly, in the above-mentioned equation (1) is satisfied, in the present example, the following equation (2) is satisfied for each of the above-mentioned dimensions. 2×(L11+L12+L13a+L13b+L14) <L21a+L21b+L22+L23+L24

[0077] Next, the above-mentioned equation (2) is described with reference to the circumferential length (the outer circumferential length) of the outer surface 310 and the circumferential length of the outer surface 410. The circumferential length of the outer surface 310 of each of the radiators 13A and 13B is defined as L10. The circumferential length of the outer surface 310 of the radiator 14 is defined as L20. Note that L10 is represented by the following equation (3). L20 is represented by the following equation (4). L10=L11+L12+L13a+L13b+L13c+L14 L20=L21a+L21b+L21c+L22+L23+L24

[0078] For the circumferential length L10 of the radiator 13A, the length of an outwardly exposed portion is represented by L10-L13c. For the circumferential length L10 of the radiator 13B, the length of an outwardly exposed portion is also represented by L10-L13c. For the circumferential length L20 of the radiator 14, the length of an outwardly exposed portion is represented by L20-L21c. In this case, the following equation (5) is satisfied for L10 and L20. 2×(L10−L13c) <L20−L21c <zusammenfassung>

[0079] The following is a summary of the battery pack 10. Note that the battery pack 10 is summarized based on the state in which the battery pack 10 is installed in the electric vehicle 1 as described above. Further, for convenience of description, the radiators 13A and 13B are also collectively referred to as "radiator 13" hereinafter. The tubes 5A and 5B are also collectively referred to as "tube 5." Similarly, the tubes 6A and 6B are also collectively referred to as "tube 6." The flow paths 390A and 390B are also collectively referred to as "flow path 390." (1) As it is in Fig. 2, the battery pack 10 includes: the plurality of battery cells 100 each having the positive electrode terminal 101 and the negative electrode terminal 102, the plurality of battery cells 100 being arranged side by side along the axial direction D1; the cooler 13 being arranged in contact with the individual battery cells 100 with the heat-conducting member (the bus bar 120 and the adhesive layer 16 in the present example) therebetween; and the cooler 14 being arranged in contact with the individual battery cells 100 with the heat-conducting member (the adhesive layer 17 in the present example) therebetween. As shown in the Fig. 2, Fig. 5 and Fig. 6, the cooler 13 is arranged above the cooler 14. As shown in the Fig. 2 and Fig. As shown in Figure 6, the cooler 14 is arranged below the individual positive electrode terminals 101 and the individual negative electrode terminals 102. The cooler 13 has a lower thermal conductivity than the cooler 14.

[0080] According to such a configuration, the cooler 13 is arranged above the cooler 14 and has a lower thermal conductivity than the cooler 14. Condensation is less likely to occur with lower thermal conductivity than with higher thermal conductivity. Thus, condensation is more likely to occur in the cooler 14 than in the cooler 13. Furthermore, the cooler 14 is arranged below the individual positive electrode terminals 101 and the individual negative electrode terminals 102. Therefore, according to the battery pack 10, water droplets caused by condensation can be prevented from adhering to the positive electrode terminal 101 and the negative electrode terminal 102. Thus, even when multiple coolers such as the coolers 13 and 14 are used, a short circuit in the battery pack 10 due to water droplets caused by condensation in the coolers can be prevented.In particular, a short circuit can be prevented from occurring between the positive electrode terminal 101 and the negative electrode terminal 102 of the battery cell 100. Note that the above-mentioned short circuit includes both a short circuit between the positive electrode terminal 101 and the negative electrode terminal 102 between adjacent battery cells 100 (a short circuit between terminals not connected by the bus bar 120) and a short circuit between the positive electrode terminal 101 and the negative electrode terminal 102 in the same battery cell 100.

[0081] (2) As it is in Fig. 6, each battery cell 100 has a bottom surface 1033. The cooler 14 is disposed below the bottom surface 1033 and is in contact with the bottom surface 1033 with the adhesive layer 17 disposed therebetween.

[0082] According to such a configuration, the cooler 14 is arranged below each battery cell 100. Thus, even if water droplets generated by the formation of condensation in the cooler 14 (especially water droplets adhering to the surface of the cooler 14) fall downward, the water droplets do not impinge on any of the battery cells 100. Therefore, a short circuit between the positive electrode terminal 101 and the negative electrode terminal 102 due to the water droplets formed in the cooler 14 can be prevented.

[0083] (3) As it is in Fig. 2, the cooler 13, with the bus bar 120 and adhesive layer 16 arranged therebetween, is in contact with the individual positive electrode terminals 101 and the individual negative electrode terminals 102.

[0084] According to such a configuration, even when a high current is supplied to or drawn from each battery cell 100, the positive electrode terminal 101 and the negative electrode terminal 102, which are more likely to generate heat in the individual battery cells 100, can be cooled, and also water droplets can be prevented from adhering to the positive electrode terminal 101 and the negative electrode terminal 102 due to the formation of condensation.

[0085] (4) As it is in Fig. 6, each battery cell 100 has a top surface 1031. As shown in Fig. 6, the positive electrode terminal 101 and the negative electrode terminal 102 protrude upward from the upper surface 1031.

[0086] According to such a configuration, the cooler 13 can be installed on the upper surface 1031 of the individual battery cells 100.

[0087] (5) As it is in Fig. As shown in Figure 5, the radiator 13 serves as a cooling tube extending along the axial direction D1 and providing a flow path 390 for the refrigerant 900. The radiator 14 serves as a cooling tube extending along the axial direction D1 and providing a flow path 490 for the refrigerant 900. The radiator 13 has an inner surface 320 in contact with the refrigerant 900 and an outer surface 310 opposite the inner surface 320. The radiator 14 has an inner surface 420 in contact with the refrigerant 900 and an outer surface 410 opposite the inner surface 420.

[0088] The outer surface 310 of the cooler 13 includes: the contact area P1, which is in contact with the positive electrode terminal 101 and the negative electrode terminal 102 with the bus bar 120 and the adhesive layer 16 therebetween; and the non-contact area Q1 excluding the contact area P1 of the outer surface 310. The outer surface 410 of the cooler 14 includes: the contact area P2, which is in contact with the individual battery cells 100 with the adhesive layer 17 therebetween; and the non-contact area Q2 excluding the contact area P2 of the outer surface 410. The non-contact area Q1 is smaller in area than the non-contact area Q2.

[0089] According to such a configuration, a portion of the outer surface 310 of the cooler 13 that is in contact with the gas in the battery pack 10 is smaller in area than a portion of the outer surface 410 of the cooler 14 that is in contact with the gas in the battery pack 10. Therefore, compared with the case where the above-mentioned relationship regarding the areas does not hold, the formation of condensation can be preferentially caused on the outer surface of the cooler 14, while the formation of condensation on the outer surface of the cooler 13 is further prevented.

[0090] (6) As it is in the Fig. 2 and Fig. As shown in Figure 3, the cooler 13 is connected to pipe 5 on the upstream side and to pipe 6 on the downstream side. Pipe 5 has a lower thermal conductivity than pipe 6.

[0091] According to such a configuration, the amount of water droplets formed by the formation of condensate can be smaller in the pipe 5 on the upstream side of the radiator 13 than in the pipe 6 on the downstream side of the radiator 13.

[0092] (7) As it is in the Fig. As shown in Figures 2 to 4, the cooler 14 is connected to pipe 7 on the upstream side and to pipe 8 on the downstream side. Pipe 7 is connected to pipe 5. Pipe 8 is connected to pipe 6. Pipe 7 has a lower thermal conductivity than pipe 8.

[0093] According to such a configuration, the amount of water droplets formed by condensation can be smaller in the tube 7 on the upstream side of the radiator 14 than in the tube 8 on the downstream side of the radiator 14. Furthermore, the refrigerant 900 can be discharged from one path to two paths (tubes 5 and 7). Furthermore, the refrigerant 900 can be converged from two paths (tubes 6 and 8) into one path. < Modifications>(First Modification)

[0094] Fig. Fig. 9 is a diagram illustrating a modification of the coolers 13A and 13B mounted above the battery module 12. As shown in Fig. 9, a radiator 13C as a modification of the radiators 13A and 13B includes the first portion 351 and the second portion 352. In the present modification, the two radiators 13C are used instead of the radiators 13A and 13B.

[0095] The radiator 13C is the same size and shape as the radiators 13A and 13B. The first portion 351 and the second portion 352 are connected to each other in the outer circumferential direction of the radiator 13C and each extend along the axial direction D1. Each portion in each of the aforementioned radiators 13A and 13B is made of the same material. In contrast, in the radiators 13C, the first portion 351 and the second portion 352 are made of different materials.

[0096] The first section 351 is provided with a groove section 361. The second section 352 is provided with a groove section 362. The first section 351 and the second section 352 are superimposed along the axial direction D3 such that the first section 351 is arranged below the second section 352. The first section 351 and the second section 352 are superimposed along the axial direction D3 such that the groove sections 361 and 362 are adjacent to each other along the axial direction D3. Typically, the first section 351 and the second section 352 are fixed to each other using an adhesive. Without being limited thereto, the cooler 13C may be formed as a single piece.

[0097] The first section 351 and the second section 352 form a flow path 390C. The groove sections 361 and 362 form the flow path 390C.

[0098] At least a part of the first portion 351 is in contact with the positive electrode terminal 101 and the negative electrode terminal 102 with the thermally conductive element (the bus bar 120 and the adhesive layer 16) interposed therebetween. The second portion 352 is farther away from the positive electrode terminal 101 and the negative electrode terminal 102 than the first portion 351. The first portion 351 has a higher thermal conductivity than the second portion 352 and a lower thermal conductivity than the cooler 14.

[0099] According to such a configuration, the first portion 351, which is in contact with the positive electrode terminal 101 and the negative electrode terminal 102, with the bus bar 120 and the adhesive layer 16 interposed therebetween, has a higher thermal conductivity than the second portion 352, which is not in contact with the bus bar 120 and the adhesive layer 16. Thus, compared with the case where the thermal conductivity of the second portion 352 is equal to or higher than the thermal conductivity of the first portion 351, the positive electrode terminal 101 and the negative electrode terminal 102 can be efficiently cooled. Furthermore, the cooler 14 can prevent the formation of condensation in the second portion 352 of the cooler 13C.

[0100] In the configuration example described above, the first portion 351 and the second portion 352 have a groove portion 361 and a groove portion 362, respectively, but the present disclosure is not limited thereto. At least one of the first portion 351 and the second portion 352 may have a groove portion forming the flow path 390C. The first portion 351 may be in direct contact with the positive electrode terminal 101 and the negative electrode terminal 102 without the bus bar 120 and the adhesive layer 16 being interposed therebetween. Alternatively, the first portion 351 may be in contact with the positive electrode terminal 101 and the negative electrode terminal 102 with only the adhesive layer 16 being interposed therebetween. (Second modification)

[0101] Fig. Fig. 10 is a diagram illustrating a further modification of the coolers 13A and 13B mounted above the battery module 12. As shown in Fig. 10, a cooler 13D includes a flow path 390D.

[0102] In the cooler 13D, the position of the flow path 390D differs from that of the flow paths 390A and 390B in the coolers 13A and 13B. The position of the flow path 390D in the cooler 13D along the axial direction D3 is lower than the position of the flow paths 390A and 390B in the coolers 13A and 13B along the axial direction D3. Thus, in the cooler 13D, the thickness (L16) on the lower surface 313 side is smaller than the thickness (L15) on the upper surface 311 side. Except for this point, the cooler 13D has the same configuration as the coolers 13A and 13B.

[0103] Even with such a configuration, the same effect can be achieved as when using the cooler 13C, which is based on the Fig. 9 is described. [Second embodiment]

[0104] A battery pack whose configuration is different from the battery pack 10 of the first embodiment will be described below. Fig. 11 is a diagram illustrating a battery pack according to the present embodiment. Fig. 11 is a cross-sectional view along the arrowed line at the same location as that in Fig. 6.

[0105] As it is in Fig. As shown in Figure 11, the battery pack 10A includes a battery module 12A, a cooler 13E, and a radiator 14. The battery module 12A includes a plurality of battery cells 100A. The battery pack 10A differs from the battery pack 10 in the first embodiment in that it includes the battery module 12A instead of the battery module 12, and the radiator 13E instead of the coolers 13A and 13B.

[0106] The battery cell 100A includes the positive electrode terminal 101, the negative electrode terminal 102, an outer casing 103A, the electrode assembly 104, the positive electrode tab 105, and the negative electrode tab 106. The outer casing 103A houses the electrode assembly 104, the positive electrode tab 105, and the negative electrode tab 106. In the present example, an electrolyte solution is enclosed in the outer casing 103A. The positive electrode tab 105 is connected to a positive electrode of the electrode assembly 104 and the positive electrode terminal 101. The negative electrode tab 106 is connected to a negative electrode of the electrode assembly 104 and the negative electrode terminal 102.

[0107] The outer housing 103A includes a top surface 1031A, a side surface 1032A, a bottom surface 1033, and a side surface 1034A. The top surface 1031A, the side surface 1032A, the bottom surface 1033, and the side surface 1034A are connected to each other in this order.

[0108] The lateral surfaces 1032A and 1034A are each part of the outer peripheral surface of the outer casing 103A. The outer peripheral surface is also part of the outer peripheral surface of the battery cell 100. The outer peripheral surface is adjacent to the upper surface 1031A and the lower surface 1033. As in the first embodiment, the outer peripheral surface includes four lateral surfaces.

[0109] The positive electrode terminal 101 and the negative electrode terminal 102 protrude along the axial direction D2 from the outer casing 103A. In particular, in the Fig. In the battery cell 100A shown in Figure 11, the positive electrode terminal 101 protrudes from the outer casing 103A in the direction D21. The positive electrode terminal 101 protrudes from the side surface 1034A along the axial direction D2. The negative electrode terminal 102 protrudes from the outer casing 103A in a direction D22. The negative electrode terminal 102 protrudes from the side surface 1032A along the axial direction D2. The bus bar 120 is arranged on the side of the positive electrode terminal 101 and the negative electrode terminal 102. In the present example, there is no adhesive layer between the cooler 13E and the bus bar 120.

[0110] The cooler 13E is arranged above the cooler 14. The cooler 14 is arranged below the positive electrode terminal 101 and the negative electrode terminal 102. In the present example, the cooler 13E is the same size and shape as the cooler 14. However, the present disclosure is not limited thereto. For example, the cooler 13E may be shorter (wider) than the cooler 14 in the axial direction D2.

[0111] Coolers 13E and 14 are made of different materials. In the present example, cooler 13E is made of the same material as coolers 13A and 13B. Thus, cooler 13E has a lower thermal conductivity than cooler 14.

[0112] The cooler 13E is attached to the top of the battery module 12A. The cooler 13E is arranged above the individual battery cells 100A. The cooler 13E is attached to the upper surface 1031A of the outer casing 103 using an adhesive. Thus, the adhesive layer 16A is located between the cooler 13E and the upper surface 1031A. The coolant 900 flows through the cooler 13E.

[0113] As described above, in the state where at least the battery pack 10A is mounted on the electric vehicle 1, the cooler 13E is disposed above the cooler 14. The cooler 14 is disposed below the positive electrode terminal 101 and the negative electrode terminal 102. The cooler 13E has a lower thermal conductivity than the cooler 14. Thus, the battery pack 10A, like the battery pack 10 in the first embodiment, prevents water droplets generated by condensation from adhering to the positive electrode terminal 101 and the negative electrode terminal 102. Therefore, even when multiple coolers such as the coolers 13E and 14 are used, a short circuit between the positive electrode terminal 101 and the negative electrode terminal 102 of the battery cell 100A caused by water droplets generated by condensation in the coolers can be prevented.

[0114] Each battery cell 100A has two side surfaces 1032A and 1034A, each of the side surfaces 1032A and 1034A having a normal direction along the axial direction D2 perpendicular to the axial directions D1 and D3 in the state where the battery pack 10A is mounted on the electric vehicle 1. The positive electrode terminal 101 protrudes from the side surface 1034A along the axial direction D2. The negative electrode terminal 102 protrudes from the side surface 1032A along the axial direction D2.

[0115] According to such a configuration, the distance between the positive electrode terminal 101 and the negative electrode terminal 102 in each battery cell 100 can be longer than in the case where the positive electrode terminal 101 and the negative electrode terminal 102 protrude from the upper surface 1031 of the battery cell 100 as shown in Fig. 6. This can prevent a short circuit between the positive electrode terminal 101 and the negative electrode terminal 102 of the same battery cell 100 caused by water droplets generated by the formation of condensation. <modifikationen>

[0116] Fig. Figure 12 is a diagram illustrating a modification of the 10A battery pack. As shown in Fig. 12, the battery pack 10B includes the battery module 12A and the coolers 13A, 13B, and 14. The battery pack 10B differs from the battery pack 10A in that it includes the coolers 13A and 13B instead of the cooler 13E.

[0117] As in the battery pack 10 in the first embodiment including the coolers 13A and 13B, in the battery pack 10B, the positions of the positive electrode terminal 101 and the negative electrode terminal 102 of the battery cell 100A are different from those in Fig. 6, the positions of the positive electrode terminal 101 and the negative electrode terminal 102 of the battery cell 100. Thus, the positions of the coolers 13A and 13B in the battery pack 10B also differ from those of the coolers 13A and 13B in the battery pack 10.

[0118] Specifically, in the battery pack 10B, just like the battery pack 10 in the first embodiment, the coolers 13A and 13B are arranged above the cooler 14. The cooler 14 is arranged below the positive electrode terminal 101 and the negative electrode terminal 102. The coolers 13A and 13B are each fixed to the battery module 12A by means of an adhesive. The cooler 13A is fixed to a side portion of the battery module 12A by means of an adhesive. Specifically, the coolers 13A and 13B are fixed to a plurality of bus bars 120 arranged one behind the other along the axial direction D1 by means of an adhesive. Specifically, the coolers 13A and 13B are fixed to the bus bar 120 by means of the adhesive layer 16 made of an adhesive.

[0119] Such a configuration also allows for a larger distance between the positive electrode terminal 101 and the negative electrode terminal 102 in each battery cell 100. Thus, a short circuit caused by the formation of condensation between the positive electrode terminal 101 and the negative electrode terminal 102 can be further prevented. Furthermore, the positive electrode terminal 101 and the negative electrode terminal 102, which are more likely to generate heat, can be efficiently cooled.

[0120] In the example described above, the battery pack 10, 10A or 10B is installed in an electric vehicle (specifically, the electric vehicle 1), but the destination to which the battery pack 10, 10A or 10B is attached is not limited to the electric vehicle.

[0121] Although the embodiments of the present disclosure are described above, the embodiments disclosed herein are illustrative and not restrictive in any respect. The scope of the present disclosure is defined by the claims and is intended to include all modifications within the meaning and scope equivalent to the claims. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2024-019308

[0001] JP 2023-165300

[0003] < / modifikationen> < / zusammenfassung>

Claims

[1] Energy storage device (10, 10A, 10B) comprising: a plurality of battery cells (100), each comprising a positive electrode terminal (101) and a negative electrode terminal (102), wherein the plurality of battery cells (100) are arranged side by side in a first axial direction; and a first cooler and a second cooler (13A to 13E, 14), wherein the first cooler and the second cooler (13A to 13E, 14) are each in contact with the individual battery cells (100) directly or with a heat-conducting element arranged therebetween, wherein the first cooler (13A to 13E) is arranged above the second cooler (14) and the second cooler (14) is arranged below the individual positive electrode terminals (101) and the individual negative electrode terminals (102), and the first cooler (13A to 13E) has a lower thermal conductivity than the second cooler (14). [2] Energy storage device (10, 10A, 10B) according to claim 1, wherein the battery cells (100) each have a first surface serving as a bottom surface (1033), and the second cooler (14) is arranged below the first surface and is in contact with the first surface directly or with the heat-conducting element arranged therebetween. [3] The energy storage device (10, 10A, 10B) according to claim 2, wherein the first cooler (13A to 13E) is in contact with the individual positive electrode terminals (101) and the individual negative electrode terminals (102) directly or with the heat-conducting member interposed therebetween. [4] Energy storage device (10, 10A, 10B) according to claim 3, wherein the battery cells (100) each further have a second surface serving as a top surface (1031, 1031A), and the positive electrode terminal (101) and the negative electrode terminal (102) protrude upward from the second surface. [5] Energy storage device (10A, 10B) according to claim 3, wherein the first axis direction is perpendicular to a vertical axis direction, the battery cells (100) each have a first lateral surface and a second lateral surface (1032A, 1034A), wherein the first lateral surface and the second lateral surface (1032A, 1034A) each have a normal direction in a second axial direction perpendicular to the first axial direction and the vertical axial direction, the positive electrode terminal (101) protrudes from the first lateral surface (1034A) in the second axial direction, and the negative electrode terminal (102) protrudes from the second lateral surface (1032A) in the second axial direction. [6] Energy storage device (10, 10B) according to one of claims 3 to 5, wherein the first cooler and the second cooler (13A to 13D, 14) each serve as a cooling tube extending in the first axial direction and having a flow path (390, 490) for the refrigerant (900); and have an inner surface (320, 420) in contact with the refrigerant (900) and an outer surface (310, 410) opposite the inner surface (320, 420), the outer surface (310) of the first cooler (13) comprises: a first contact area which is in contact with the individual positive electrode terminals (101) and the individual negative electrode terminals (102) directly or with the heat-conducting element arranged therebetween, and a first non-contact area except for the first contact area of ​​the outer surface (310), the outer surface (410) of the second cooler (14) comprises: a second contact area which is in contact with the individual battery cells (100) directly or with the heat-conducting element arranged therebetween; and a second non-contact region excluding the second contact region from the outer surface (410); and the first non-contact area is smaller in area than the second non-contact area. [7] Energy storage device (10) according to claim 6, wherein the first cooler (13C) comprises a first portion and a second portion (351, 352) which are adjacent to each other in an outer circumferential direction of the first cooler (13C), the first portion and the second portion (351, 352) each extending in the first axial direction, the first section (351) and the second section (352) form the flow path (390), at least one of the first and second sections (351, 352) comprises a groove section (361, 362) forming the flow path (390), at least a part of the first section (351) is in contact with the individual positive electrode terminals (101) and the individual negative electrode terminals (102) directly or with the heat-conducting element arranged therebetween, the second section (352) of the individual positive electrode terminals (101) and the individual negative electrode terminals (102) is further away than the first section (351), and the first section (351) has a higher thermal conductivity than the second section (352) and a lower thermal conductivity than the second cooler (14). [8] Energy storage device (10, 10A, 10B) according to claim 1, wherein the first cooler (13A to 13E) is connected on an upstream side to a first pipe (5A, 5B) and on a downstream side to a second pipe (6A, 6B), and the first tube (5A, 5B) has a lower thermal conductivity than the second tube (6A, 6B). [9] Energy storage device (10, 10A, 10B) according to claim 8, wherein the second cooler (14) is connected on the upstream side to a third pipe (7) and on the downstream side to a fourth pipe (8), the third pipe (7) is connected to the first pipe (5A, 5B), the fourth pipe (8) is connected to the second pipe (6A, 6B), and the third tube (7) has a lower thermal conductivity than the fourth tube (8). [10] Electrically powered vehicle (1) comprising: a plurality of battery cells (100), each comprising a positive electrode terminal (101) and a negative electrode terminal (102), wherein the plurality of battery cells (100) are arranged side by side in a predetermined axial direction; and a first cooler and a second cooler (13A to 13E, 14), wherein the first cooler and the second cooler (13A to 13E, 14) are each in contact with the individual battery cells (100) directly or with a heat-conducting element arranged therebetween, wherein the first cooler (13A to 13E) is arranged above the second cooler (14), the second cooler (14) is arranged below the individual positive electrode terminals (101) and the individual negative electrode terminals (102), and the first cooler (13A to 13E) has a lower thermal conductivity than the second cooler (14).

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