Cooling structure for a battery

Abstract

Cooling structure for a battery (10; 310) to be mounted in a vehicle, the cooling structure for a battery (10; 310) comprising: a cooling material layer (40; 340) including a first cooling material (41; 341) arranged at least partially along a surface of the battery (10; 310) and a second cooling material (42; 342; 442) arranged to at least partially cover a surface of the first cooling material (41; 341) on a side opposite the battery (10; 310); a cooling passage (60; 260; 360; 460) through which a coolant is circulated for cooling the cooling material layer (40; 340), a battery case (11; 311) in a flat box shape; a wound body (20; 320) accommodated in the battery case (11; 311), the wound body (20; 320) being formed by winding a sheet-like or plate-like wound body into a flat circular shape; and Electrode terminals (31, 32; 331, 332) provided on a respective one of a pair of first surface portions (11a; 311a) of surfaces of the battery case (11; 311) arranged on both sides in a direction of a main axis of the wound body (20; 320) and connected to the wound body (20; 320) in the battery case (11; 311), where each of the first and second cooling materials (41; 42; 341; 342; 442) is a cooling or cold storage material having a phase transition temperature at which a phase transition from a solid phase to a liquid phase takes place within a range lower than a predetermined temperature, a second phase transition temperature (Tc2), which is the phase transition temperature of the second cooling material (42; 342), is higher than a first phase transition temperature (Tc1), which is the phase transition temperature of the first cooling material (41; 341), the cooling material layer (40; 340) is a layer which at least partially covers the surfaces of the battery case (11; 311), and on a pair of second surface portions (11b; 311b) of the surfaces of the battery case (11; 311) facing surface portions of the wound body (20; 320) arranged on both sides in a direction of a minor axis, the cooling material layer (40; 340) is provided in a portion close to the electrode terminals (31, 32; 331, 332), while an accessory, namely a terminal box (13) and a battery management system BMS (14), of the battery (10; 310) is arranged in a portion remote from the electrode terminals (31, 32; 331, 332) without providing the cooling material layer (40; 340).

Description

[0001] The present invention relates to a cooling structure for a battery according to claim 1 and a method for providing such a cooling structure.

[0002] Conventionally, as a system for cooling a battery, a system in which a cooling or cold storage material is attached to a surface of the battery has been known.

[0003] A cooling system using a cooling material is a system that cools a battery by utilizing an endothermic reaction during a phase transition from a solid phase to a liquid phase. Therefore, to properly cool the battery when the cooling material becomes a liquid phase, it is necessary to cool the cooling material and return the cooling material to a solid phase.

[0004] For example, JP 2013-229205 A discloses a cooling structure for a battery pack (battery), the cooling structure including a cooling material disposed in contact with the battery pack to cool the battery pack by utilizing latent heat of a phase transition, wherein a ventilation hole through which cooling air is circulated is formed in the cooling material.

[0005] However, in the cooling system described in JP 2013-229205 A, the cooling air flows after heat exchange with the cooling material in a portion downstream of the vent hole. Therefore, while a portion upstream of the vent hole is greatly cooled, the portion downstream of the vent hole is not much cooled. Accordingly, a temperature distribution occurs in the cooling material, and as a result, a temperature distribution also occurs in the battery.

[0006] DE 10 2011 106 690 A1 discloses batteries with phase-change materials. The phase-change materials improve heating and cooling properties under various vehicle operating conditions. The battery pack includes a battery cell and a compressible insulator plate containing a phase-change material adjacent to the battery cell. A first phase-change material exhibits a phase change from liquid to solid at a temperature below approximately 0°C, and a second phase-change material exhibits a phase change from solid to liquid at a temperature above approximately 40°C.

[0007] The technology disclosed herein has been made in view of such a point, or the object of the present invention is to reduce the temperature distribution in a battery having a cooling structure using a cooling or cold storage material.

[0008] This object is achieved according to the invention by a cooling structure and a method having the features of the independent claims. Further developments are defined in the dependent claims.

[0009] In order to solve the above problem, in the technology disclosed herein, which is aimed at a cooling structure for a battery to be mounted on a vehicle, the cooling structure includes: a cooling material layer including a first cooling material arranged at least partially along a surface of the battery, and a second cooling material arranged to at least partially cover a surface of the first cooling material on a side opposite to the battery; and a cooling passage through which a coolant for cooling the cooling material layer is circulated, each of the first and second cooling materials being a cooling material.A cold storage material having a phase transition temperature at which a phase transition from a solid phase to a liquid phase takes place within a range lower than a predetermined temperature, and a second phase transition temperature, which is the phase transition temperature of the second cooling material, is higher than a first phase transition temperature, which is the phase transition temperature of the first cooling material.

[0010] According to this configuration, when the first cooling material reaches the first phase transition temperature through heat exchange with the battery, the temperature of the second cooling material also becomes approximately the first phase transition temperature. Therefore, the first cooling material is less likely to be affected by the outside air and only absorbs heat from the battery. Thus, the temperature of the first cooling material is easily maintained around the first phase transition temperature, and the latent heat of the first cooling material makes the temperature of the entire battery substantially constant. Even when the temperature of the second cooling material reaches the second phase transition temperature, a constant temperature is again maintained by the latent heat of the second cooling material during the phase transition of the second cooling material.Accordingly, the temperature distribution in the battery can be reduced.

[0011] The cooling structure for a battery may further include: a battery temperature detection unit that detects a temperature of the battery, and / or a pump for circulating the coolant through the cooling passage, and / or the cooling passage is a passage that cools the second cooling material, and when the temperature detected by the battery temperature detection unit is equal to or higher than the second phase transition temperature, the pump circulates the coolant through the cooling passage.

[0012] That is, the temperatures of the first and second cooling materials tend to be lower than the temperature of the battery. Therefore, even when the temperature of the battery becomes the second phase transition temperature, the temperature of the second cooling material is substantially lower than the second phase transition temperature. According to the above-described configuration, the second cooling material can be cooled before it reaches the second phase transition temperature. That is, it is possible to start cooling the second cooling material before the temperature of the second cooling material becomes constant due to the latent heat of the second cooling material. Thus, the battery, the first cooling material, and the second cooling material can be highly responsively cooled.In addition, the cooling material layer can be easily maintained at temperatures equal to or higher than the first phase transition temperature and lower than the second phase transition temperature, and the temperature distribution in the battery can be more effectively reduced.

[0013] The cooling structure for a battery in which the cooling passage cools the second cooling material may further include a cooling material temperature detecting unit that detects a temperature of the first cooling material, wherein the pump circulates the coolant through the cooling passage until the temperature detected by the cooling material temperature detecting unit becomes lower than the first phase transition temperature.

[0014] According to this configuration, the temperature of the first cooling material is maintained slightly around or in the range of the first phase transition temperature. Thus, the temperature distribution in the battery can be reduced more effectively.

[0015] The cooling structure for a battery in which the cooling passage cools the second cooling material may further include a casing arranged to at least partially cover a surface of the second cooling material on an opposite side to the first cooling material, wherein the cooling passage is arranged in a wall portion constituting the casing.

[0016] According to this configuration, it is possible to improve the degree of freedom in the arrangement of the cooling passage. Thus, the cooling passage can be arranged to achieve higher cooling efficiency. As a result, the temperature distribution in the battery can be more effectively reduced.

[0017] According to one aspect of the invention of the cooling structure for a battery, the battery includes: a battery case in a flat box shape; a wound body accommodated in the battery case, the wound body formed by winding a sheet-like material.sheet-like wound body is formed into a flat circular shape; and terminals which are provided on a respective one of a pair of first case surface portions of surfaces of the battery case which are arranged on both sides in a direction of a major axis of the wound body and are connected to the wound body in the battery case, the cooling material layer is a layer which at least partially covers the surfaces of the battery case, and on a pair of second case surface portions of the surfaces of the battery case which face surface portions of the wound body which are arranged on both sides in a direction of a minor axis, the cooling material layer is provided in a portion close to the terminals, while an accessory of the battery is arranged in a portion away from the terminals without providing the cooling material layer.

[0018] That is, among the battery case surfaces, the area of ​​the pair of second case surface portions facing the wound body surface portions located on both sides in the minor axis direction is larger compared to the other surface portions of the battery case surfaces. Therefore, the second case surface portion has higher heat radiation efficiency compared to the other surface portions. Accordingly, even if the cooling material layer is not disposed in a part of the second case surface portions, it is possible to sufficiently cool the battery.

[0019] On the other hand, heat is easily generated near the terminals of the battery, and the temperature tends to be higher. Therefore, by disposing the cooling material layer in a portion of the second case surface portion near the terminals, the battery can be efficiently cooled.

[0020] Thus, even in a location such as the engine compartment of a vehicle where accessories are likely to be located, the temperature distribution in the battery may be reduced.

[0021] According to another aspect of the invention of the cooling structure for a battery, the battery includes a plurality of battery cells, and each of the battery cells includes: a battery case in a shape of a flat box; a wound body accommodated in the battery case, the wound body formed by winding a sheet-like or flat-shaped battery.sheet-like wound body is formed into a flat circular shape; and terminals which are provided on a respective one of a pair of first case surface portions of surfaces of the battery case which are arranged on both sides in a direction of a major axis of the wound body and are connected to the wound body in the battery case, wherein the battery cells are arranged side by side in a direction of a minor axis of the wound body, the cooling material layer is a layer which at least partially covers the surfaces of the battery case, and in two end-side battery cells arranged on both end sides in a parallel direction among the battery cells, on each of surface portions arranged on outermost sides in the parallel direction, the cooling material layer is provided in a portion close to the terminals, while an accessoryAccessory part of the battery is arranged in a section away from the terminals without providing the cooling material layer.

[0022] That is, since the battery cells are arranged side by side in the direction of the minor axis of the wound body, the area of ​​the surface portions located in the parallel direction among the surfaces of each of the battery cells is larger compared to the other surface portions of the surfaces of the battery case. Accordingly, even if the cooling material layer is not disposed in a part of the surface portion located on the outermost side in the parallel direction, it is possible to cool the battery efficiently.

[0023] On the other hand, heat is easily generated near the terminals of the battery, and the temperature tends to be higher. Therefore, even in the surface portion located on the outermost side in the parallel direction, the battery can be efficiently cooled by disposing the cooling material layer in a portion near the terminals.

[0024] Thus, even in a location such as the engine compartment of a vehicle where accessories are likely to be located, the temperature distribution in the battery may be reduced.

[0025] According to a further aspect, a method for providing a cooling structure for a battery is provided, comprising: providing a cooling material layer including a first cooling material disposed at least partially along a surface of the battery and a second cooling material disposed to at least partially cover a surface of the first cooling material on a side opposite the battery; providing a cooling passage through which a coolant is circulated for cooling the cooling material layer, providing a battery housing in a flat box shape; providing a wound body accommodated in the battery case, the wound body being formed by winding a sheet-like winding body into a flat circular shape; and providing terminals formed on a respective one of a pair of first case surface portions of surfaces of the battery case, which are arranged on both sides in a direction of a main axis of the wound body and are connected to the wound body in the battery case, where each of the first and second cooling materials is a cooling or cold storage material having a phase transition temperature at which a phase transition from a solid phase to a liquid phase takes place within a range lower than a predetermined temperature, and a second phase transition temperature, which is the phase transition temperature of the second coolant, is higher than a first phase transition temperature, which is the phase transition temperature of the first cooling material, the cooling material layer is a layer which at least partially covers the surfaces of the battery casing, and on a pair of second case surface portions of the surfaces of the battery case facing surface portions of the wound body located on both sides in a direction of a minor axis, the cooling material layer is formed in a portion close to the terminals, while an accessory of the battery is arranged in a portion away from the terminals without providing the cooling material layer.

[0026] According to yet another aspect, there is provided a method of providing a cooling structure for a battery, comprising: providing a cooling material layer including a first cooling material disposed at least partially along a surface of the battery and a second cooling material disposed to at least partially cover a surface of the first cooling material on a side opposite the battery; providing a cooling passage through which a coolant is circulated for cooling the cooling material layer, wherein the battery includes a plurality of battery cells and each of the battery cells contains: a battery housing in a flat box shape; a wound body accommodated in the battery case, the wound body being formed by winding a sheet-like winding body into a flat circular shape; and Terminals formed on a respective one of a pair of first case surface portions of surfaces of the battery case, which are arranged on both sides in a direction of a main axis of the wound body and are connected to the wound body in the battery case, where each of the first and second cooling materials is a cooling or cold storage material having a phase transition temperature at which a phase transition from a solid phase to a liquid phase takes place within a range lower than a predetermined temperature, and a second phase transition temperature, which is the phase transition temperature of the second cooling material, is higher than a first phase transition temperature, which is the phase transition temperature of the first cooling material, the battery cells are arranged side by side in a direction of a minor axis of the wound body, the cooling material layer is a layer which at least partially covers the surfaces of the battery casing, and in two end-side battery cells arranged on both end sides in a parallel direction among the battery cells, on each of surface portions arranged on outermost sides in the parallel direction, the cooling material layer is formed in a portion close to the terminals, while an accessory of the battery is formed in a portion away from the terminals without providing the cooling material layer.

[0027] Preferably, the method further comprises: providing a battery temperature detection unit which detects a temperature of the battery, and / or providing a pump for circulating the coolant through the cooling passage, and / or the cooling passage is formed as a passage which cools the second cooling material. Furthermore, the method preferably comprises providing a cooling material temperature detection unit which detects a temperature of the first cooling material.

[0028] As described above, according to the technology disclosed herein, since the heat of the first cooling material is continuously absorbed by the second cooling material until the second cooling material undergoes a phase transition from a solid phase to a liquid phase, the temperature of the first cooling material is easily maintained near the first phase transition temperature. Accordingly, the temperature distribution in the battery can be reduced. Short description of the drawings: Fig. 1 is a schematic diagram of a cooling system for cooling a battery to which a cooling structure according to Embodiment 1 is applied. Fig. 2 is a perspective view of a battery employing the cooling structure. Fig. 3 is a schematic cross-sectional view showing an arrangement of a cooling material layer and a cooling passage, and is a cross-sectional view taken along line III-III in Fig. 2. Fig. Fig. 4 is a schematic cross-sectional view showing an arrangement of the cooling material layer and the cooling passage, and is a cross-sectional view taken along line IV-IV in Fig. 2. Fig. 5 is a time chart showing temperature changes of the battery, a first cooling material, and a second cooling material when cooling control is performed. Fig. 6 is a flowchart showing a processing operation of cooling control performed by an ECU. Fig. Figure 7 is a schematic diagram showing a modification of the cooling system. Fig. 8 is a view equivalent to Fig. 3 for a battery employing a cooling structure according to an embodiment 2. Fig. 9 is an exploded perspective view of a battery employing a cooling structure according to Embodiment 3. Fig. 10 is a view equivalent to Fig. 3 for the battery employing the cooling structure according to Embodiment 3. Fig. 11 is a view equivalent to Fig. 3 for a battery employing a cooling structure according to an embodiment 4.

[0029] Hereinafter, exemplary embodiments are described in detail with reference to the drawings. (Embodiment 1)

[0030] Fig. 1 shows a cooling system 100 for cooling a battery 10 to which a cooling structure according to an embodiment 1 is applied, and Fig. 2 shows the battery 10 to which the cooling structure is applied. The battery 10 is, for example, a lithium-ion battery to be mounted in an engine compartment of a motor vehicle. From the viewpoint of power capacity and deterioration prevention, an optimal temperature range for lithium-ion batteries is, for example, about 25°C to about 60°C. Therefore, when the battery 10 is mounted on a vehicle, a cooling system 100 for the battery 10 is required independently of a cooling system for an engine. The battery 10 may be arranged under a trunk compartment or the like.

[0031] The cooling system 100 includes a pump 101 for discharging coolant and a radiator 102 for cooling the coolant after heat exchange with the battery 10. The pump 101 is an electric pump and is controlled for operation by an ECU (electronic control unit) 103. A liquid temperature sensor SN1 for detecting the temperature of the coolant is arranged on the immediate downstream side of the pump 101. The radiator 102 is arranged on a vehicle rear side of a grille cover (not shown). The coolant flowing through the radiator 102 is cooled by heat exchange with the airflow that has passed through the grille cover.

[0032] The ECU 103 is a controller based on a known microcomputer and includes: a central processing unit (CPU) that executes programs; a memory consisting of, for example, RAM (Random Access Memory) and ROM (Read Only Memory) and storing programs and data; and an input / output bus for inputting and outputting electrical signals. Detection signals from a plurality of temperature sensors SN2 to SN4 described later, in addition to the liquid temperature sensor SN1, and a detection signal from a battery SOC sensor SN5 described later are input to the ECU 103. The ECU 103 controls the operation of the pump 101 based on the detection signals from the respective temperature sensors SN1 to SN4, the detection signal from the battery SOC sensor SN5, and information stored in advance.The radiator 102 is a radiator different from the radiator used in the cooling system for an engine.

[0033] The battery 10 includes a battery case 11 in a flat box shape, a wound body 20 accommodated in the battery case 11, and a positive electrode terminal 31 and a negative electrode terminal 32 provided in the battery case 11 and connected to the wound body 20.

[0034] The wound body 20 is formed by winding a positive electrode and a negative electrode with a separator therebetween. Each of the positive electrode, the negative electrode, and the separator is in the form of a sheet. As shown in Fig. 3, the wound body 20 has a flat circular, cylindrical, or elliptical shape. The wound body 20 has curved portions 20a at both ends in the direction of a major axis and has flat surface portions 20b at both ends in the direction of a minor axis.

[0035] The direction of the major axis is the direction in which the shape of the wound body 20 has the greatest length, and the direction of the minor axis is a direction normal to the major axis direction in which the length of the wound body 20 is less than the length of the wound body in the major axis direction.

[0036] As this is Fig. As shown in Fig. 4, a positive electrode current collector 21 is provided at one end portion in a winding axis direction of the wound body 20, and a negative electrode current collector 22 is provided at the other end portion in the winding axis direction of the wound body 20. The positive electrode current collector 21 is connected to the positive electrode terminal 31 through a positive electrode connecting part 23. The negative electrode current collector 22 is connected to the negative electrode terminal 32 through a negative electrode connecting part 24.

[0037] As this is Fig. 2, the battery case 11 has a rectangular parallelepiped shape. The battery case 11 includes: a pair of first case surface portions 11a located on both sides in the direction of the major axis of the wound body 20 and facing the curved portions 20a of the wound body 20; a pair of second case surface portions 11b located on both sides in the direction of the minor axis of the wound body 20 and facing the flat surface portions 20b of the wound body 20; and a pair of third case surface portions 11c located on both sides in the direction of the winding axis of the wound body 20. The positive electrode terminal 31 and the negative electrode terminal 32 are provided on one of the pair of first case surface portions 11a.The interior of the battery case is filled with an electrolytic liquid, and the wound body 20 is immersed in the electrolytic liquid in the battery case 11.

[0038] The battery temperature sensor SN2 for detecting a surface temperature of the battery case 11 is arranged on a surface of the battery case 11. The battery temperature sensor SN2 is an example of a battery temperature detection unit.

[0039] A cooling material layer 40 for cooling the battery 10 is arranged on the portions of the battery case 11 except the first case surface portion 11a, which is provided with the terminals 31, 32. The cooling material layer 40 and the battery 10 are covered or surrounded together with a case 50 from the outside. The illustration of the case 50 is shown in Fig. 2 omitted.

[0040] As this is Fig. 3 and Fig. As shown in FIG. 4, the cooling material layer 40 includes two cooling materials, namely, a first cooling material 41 and a second cooling material 42. The cooling material layer 40 covers the surface portion on the opposite side to the terminals 31, 32 of the pair of first case surface portions 11a, and the entire surfaces of the pair of third case surface portions 11c. On the other hand, for the pair of second case surface portions 11b, only half portions near the terminals 31, 32 are covered.

[0041] The first cooling material 41 is arranged along the surfaces of the battery 10, that is, along the respective surfaces 11a to 11c of the battery casing 11. The second cooling material 42 is arranged in contact with the first cooling material 41 to cover a surface of the first cooling material 41 on the opposite side to the battery 10. Each of the first and second cooling materials 41, 42 is a cooling material or cold storage material having a phase transition temperature at which a phase transition from a solid phase to a liquid phase occurs within a range between equal to or higher than a first predetermined temperature and lower than a second predetermined temperature. Specifically, the first and second cooling materials 41, 42 are, for example, paraffin hydrocarbons or transition metal ceramics stored in bags.The first predetermined temperature is, for example, about 25°C, which is the lower limit of the suitable temperature range of the battery 10, and the second predetermined temperature is, for example, about 60°C, which is the upper limit of the suitable temperature range of the battery 10.

[0042] In Embodiment 1, a second phase transition temperature Tc2, i.e., the phase transition temperature of the second cooling material 42, is higher than a first phase transition temperature Tc1, which is the phase transition temperature of the first cooling material 41. This can be done by varying the carbon number of paraffinic hydrocarbon constituting the first cooling material 41 and the carbon number of paraffinic hydrocarbon constituting the second cooling material 42. The difference between the first phase transition temperature Tc1 and the second phase transition temperature Tc2 is, for example, about 5°C. The difference between the second phase transition temperature Tc2 and the second predetermined temperature is, for example, about 5°C.

[0043] As this is Fig. 3 and Fig. As shown in Fig. 4, the casing 50 is arranged to cover a surface of the second cooling material 42 on the opposite side to the first cooling material 41. The casing 50 is arranged in contact with the second cooling material 42 except for a lid portion covering the terminals 31, 32. The casing 50 does not need to be in direct contact with the entire second cooling material 42, and a gap may be partially formed between the casing 50 and the second cooling material 42.

[0044] As this is Fig. 3 and Fig. As shown in FIG. 4, in a wall portion constituting the casing 50, a cooling passage 60 is formed through which a coolant for cooling the second cooling material 42 circulates. The cooling passage 60 is formed by piercing the wall portion constituting the casing 50 or inserting a pipe into the wall portion. The cooling passage 60 includes: a first channel 61 in which the coolant flows in the direction of the winding axis along the portion on the opposite side to the terminals 31, 32 in the direction of the main axis and then flows to the side of the terminals 31, 32 in the direction of the main axis; and a second passage 62 in which, after flowing to the side of the ports 31, 32 in the direction of the major axis, the coolant branches and flows in the direction of the minor axis to surround the periphery of the ports 31, 32.After the first channel 61 and the second channel 62 are separated on the inlet side, the first channel 61 and the second channel 62 merge again on the outlet side.

[0045] As this is Fig. 2 and Fig. 3, in a portion of one of the second case surfaces 11b of the battery case 11 where the cooling material layer 40 is not formed, that is, a half portion of one second case surface 11b on the far side from the terminals 31, 32, a terminal box 13 as an accessory of the battery 10 is arranged. A BMS 14 (Battery Management System) as an accessory of the battery 10 is arranged in a half portion of the other second case surface 11b on the far side from the terminals 31, 32. For example, the battery SOC sensor SN5 for detecting the state of charge (SOC) of the battery 10 is stored in the BMS 14. The battery SOC sensor SN5 detects the SOC of the battery 10 based on the voltage of the battery 10 or the like.

[0046] As this is Fig. 2 and Fig. 3, the portion of the housing 50 where the terminal box 13 is arranged and the portion where the BMS 14 is arranged are opening portions.

[0047] Two cooling material temperature sensors SN3, SN4 are arranged on a surface of the first cooling material 41. The cooling material temperature sensor SN3 is arranged on the inlet side of the cooling passage 60, and the cooling material temperature sensor SN4 is arranged on the outlet side of the cooling passage 60. Hereinafter, the cooling material temperature sensor SN3 will be referred to as the inlet-side cooling material temperature sensor SN3, and the cooling material temperature sensor SN4 will be referred to as the outlet-side cooling material temperature sensor SN4. Each of the inlet-side and outlet-side cooling material temperature sensors SN3, SN4 is an example of the cooling material temperature detection unit.

[0048] In Embodiment 1, by covering the periphery of the first cooling material 41 with the second cooling material 42, it is possible to appropriately cool the battery 10 while reducing the temperature distribution in the battery 10. This will be explained with reference to the timing chart of Fig. 5 are described.

[0049] Fig. Figure 5 is a time chart showing the temperature change of the battery 10, the temperature change of the first cooling material 41, and the temperature change of the second cooling material 42. The broken line indicates the temperature of the battery 10, the one-dotted line indicates the temperature of the first cooling material 41, and the solid line indicates the temperature of the second cooling material 42. Fig. 5, the straight line shown by the two-dot chain line is an upper limit temperature Tmax of the battery 10 and is a temperature corresponding to the second predetermined temperature.

[0050] First, assume that at time t0, the temperature of the battery 10 began to rise. At this time, while the first cooling material 41 exchanges heat with the battery 10, the second cooling material 42 exchanges heat with the first cooling material 41, and the temperatures of the first cooling material 41 and the second cooling material 42 rise. Next, assume that at time t1, the temperature of the first cooling material 41 reaches the first phase transition temperature Tc1. When the temperature of the first cooling material 41 reaches the first phase transition temperature Tc1, the temperatures of the battery 10, the first cooling material 41, and the second cooling material 42 become constant due to latent heat for a phase transition of the first cooling material 41 from a solid phase to a liquid phase. Specifically, the temperature of the second cooling material 42 becomes approximately the first phase transition temperature Tc1.Next, at a time t2, when the first cooling material 41 completely undergoes a phase transition to a liquid phase, the temperatures of the battery 10, the first cooling material 41, and the second cooling material 42 again rise due to heat exchange. After that, at a time t3, when the temperature of the second cooling material 42 reaches the second phase transition temperature Tc2, the temperatures of the battery 10, the first cooling material 41, and the second cooling material 42 become constant due to latent heat of a phase transition of the second cooling material 42 from a solid phase to a liquid phase. Then, for example, at a time t4, when the pump 101 is operated, the second cooling material 42 is cooled, and accordingly, the first cooling material 41 and the battery 10 are also cooled.

[0051] As described above, when the first cooling material 41 reaches the first phase transition temperature Tc1 due to heat exchange with the battery 10, the temperature of the second cooling material 42 also becomes approximately the first phase transition temperature Tc1. Therefore, the first cooling material 41 is less likely to be affected by the ambient air and only absorbs heat from the battery 10. Thus, the temperature of the first cooling material 41 is easily maintained around the first phase transition temperature Tc1, and the latent heat of the first cooling material 41 also makes the temperature of the entire battery 10 substantially constant. Even when the temperature of the second cooling material 42 reaches the second phase transition temperature Tc2, a constant temperature is again maintained by the latent heat of the second cooling material 42 during the phase transition of the second cooling material 42.Accordingly, the temperature distribution in the battery 10 can be reduced.

[0052] Here, in the time diagram shown in Fig. 5, cooling is performed after the temperature of the second cooling material 42 reaches the second phase transition temperature Tc2. However, the battery 10, which is the original cooling target, is cooled after the second cooling material 42 is cooled and the first cooling material 41 is cooled. That is, as shown in Fig. 5, there is a time delay between the start of cooling of the second cooling material 42 and when the battery 10 is cooled. Therefore, in Embodiment 1, when the surface temperature of the battery 10, which is detected by the battery temperature sensor SN2, is equal to or higher than the second phase transition temperature Tc2, the ECU 103 causes the pump 101 to circulate the coolant through the cooling passage 60. Basically, the temperatures of the first and second cooling materials 41, 42 are lower than the temperature of the battery 10. Therefore, if the cooling of the second cooling material 42 can be started when the battery 10 has become equal to or higher than the second phase transition temperature Tc2, the second cooling material 42 can be cooled before it reaches the second phase transition temperature Tc2. That is,Cooling of the second cooling material 42 can be started before the temperature of the second cooling material 42 becomes constant due to the latent heat of the second cooling material 42. Thus, the battery 10, the first cooling material 41, and the second cooling material 42 can be highly responsively cooled. Furthermore, the cooling material layer 40 can be easily maintained within a temperature range between the first phase transition temperature Tc1 or higher and lower than the second phase transition temperature Tc2, and the temperature distribution in the battery 10 can be more effectively reduced.

[0053]

[0048] Furthermore, in Embodiment 1, even when the surface temperature of the battery 10 is lower than the second phase transition temperature Tc2, the ECU 103 causes the pump 101 to circulate the coolant through the cooling passage 60 when judging from the current heating value of the battery 10 and the like that the surface temperature of the battery 10 will reach the upper limit temperature Tmax. Thus, it is possible to appropriately prevent the battery 10 from reaching the upper limit temperature Tmax. This situation may occur, for example, when the power consumed by the vehicle-mounted electrical components increases.

[0054] In Embodiment 1, when the coolant is circulated through the cooling passage 60 by the pump 101, the ECU 103 circulates the coolant through the cooling passage 60 by the pump 101 until the temperatures to be obtained by the cooling material temperature sensors SN3, SN4 become lower than the first phase temperature Tc1, specifically, until the temperatures become a temperature lower than the first phase transition temperature Tc1 by a third predetermined temperature Ta. This makes it easier to maintain the temperature of the battery 10 constant by utilizing the latent heat of the first cooling material 41. Accordingly, the temperature distribution in the battery 10 can be more effectively reduced.The third predetermined temperature Ta is such a temperature that a value obtained by subtracting the third predetermined temperature Ta from the first phase transition temperature Tc1 is not lower than the first predetermined temperature (about 25°C). This is because if the temperature of the battery 10 becomes too low, the internal resistance increases.

[0055] Next, a processing operation of the ECU 103 when cooling the battery 10 will be described with reference to Fig. 6. In an initial or starting state, the pump 101 is not operated.

[0056] First, in a step S1, the ECU 103 reads information from each of the sensors SN1 to SN5.

[0057] In the next step S2, the ECU 103 determines whether or not the detection result of the battery temperature sensor SN1 is equal to or higher than the second phase transition temperature Tc2. If YES, that is, if the detection result of the battery temperature sensor SN1 is equal to or higher than the second phase transition temperature Tc2, the ECU 103 proceeds to step S3, while if NO, that is, if the detection result of the battery temperature sensor SN1 is lower than the second phase transition temperature Tc2, the ECU 103 proceeds to step S8.

[0058] In step S3, the ECU 103 causes the pump 101 to operate. Thus, the coolant is circulated through the cooling passage 60.

[0059] In the next step S4, the ECU 103 determines whether or not the detected temperature by the inlet-side cooling material temperature sensor SN3 is equal to or lower than a temperature (Tc1-Ta) lower than the first phase transition temperature Tc1 by the third predetermined temperature Ta. If YES, that is, if the detected temperature by the inlet-side cooling material temperature sensor SN3 is equal to or lower than (Tc1-Ta), the ECU 103 proceeds to a step S5, while if NO, that is, if the detected temperature by the inlet-side cooling material temperature sensor SN3 is higher than (Tc1-Ta), the ECU 103 continues to make a determination in a step S4 until the detected temperature by the inlet-side cooling material temperature sensor SN3 becomes equal to or lower than (Tc1-Ta).

[0060] In step S5, the ECU 103 controls various devices so that the coolant liquid temperature to be detected by the liquid temperature sensor SN1 becomes (Tc1-Ta). In step S5, for example, the ECU 103 adjusts the flow rate of the pump 101 or adjusts the opening of the grille cover to make the coolant liquid temperature (Tc1-Ta).

[0061] In the next step S6, the ECU 103 determines whether the temperature detected by the outlet-side coolant temperature sensor SN4 is (Tc1-Ta) or not. If YES, that is, if the temperature detected by the outlet-side coolant temperature sensor SN4 is (Tc1-Ta), the ECU 103 proceeds to a step S7, while if NO, that is, if the temperature detected by the outlet-side coolant temperature sensor SN4 is not (Tc1-Ta), the ECU 103 continues to make a determination in step S6 until the temperature detected by the outlet-side coolant temperature sensor SN4 becomes (Tc1-Ta).

[0062] In the next step S7, the ECU 103 stops the operation of the pump 101. After the step S7, the ECU 103 makes a return.

[0063] On the other hand, in step S8, the ECU 103 calculates a heat capacity C until reaching the upper limit temperature Tmax from the current surface temperature of the battery 10.

[0064] In the next step S9, the ECU 103 determines whether a value obtained by adding the current cooling capacity of the battery 10 to the heat capacity C calculated in step S8 is greater than the current heat value of the battery 10. The ECU 103 calculates the current cooling capacity of the battery 10 by referring to a map based on the liquid temperature of the coolant, the temperature of the cooling material layer 40, etc. The ECU 103 calculates the current heat value of the battery 10 by multiplying an internal resistance of the battery 10, calculated from the detection result of the battery temperature sensor SN1, the detection result of the battery SOC sensor SN5, etc., by the square of the current. If YES, that is, if the value of (heat capacity C + cooling capacity) is greater than the current heating or heat value of the battery 10, the ECU 103 makes a return, while if NO, that iswhen the value of (heat capacity C + cooling ability) is equal to or less than the current heat value of the battery 10, the ECU 103 proceeds to step S3 and operates the pump 101 to cool the battery 10.

[0065] Thus, in Embodiment 1, the cooling system includes: the cooling material layer 40 including the first cooling material 41 arranged along the surface of the battery 10 and the second cooling material 42 arranged to cover the surface of the first cooling material 41 on the opposite side to the battery 10; and the cooling passage 60 through which the coolant for cooling the cooling material layer 40 is circulated, wherein the first and second cooling materials 41, 42 are cooling and cold storage materials having phase transition temperatures at which a phase transition from a solid phase to a liquid phase takes place within a range lower than the second predetermined temperature, and the second phase transition temperature Tc2, that is,the phase transition temperature of the second cooling material 42 is higher than the first phase transition temperature Tc1, which is the phase transition temperature of the first cooling material 41. Thus, when the first cooling material 41 reaches the first phase transition temperature Tc1 through heat exchange with the battery 10, the temperature of the second cooling material 42 also becomes approximately the first phase transition temperature Tc1. Therefore, the first cooling material 41 is less likely to be affected by the ambient air and merely absorbs heat from the battery 10. Accordingly, the temperature of the first cooling material 41 is easily maintained around the first phase transition temperature Tc1, and the temperature of the entire battery 10 remains substantially constant due to the latent heat of the first cooling material 41. Accordingly, the temperature distribution in the battery 10 can be reduced.

[0066] In Embodiment 1, when the temperature of the battery 10 detected by the battery temperature sensor SN2 is equal to or higher than the second phase transition temperature Tc2, the ECU 103 causes the pump 101 to circulate the coolant through the cooling passage 60. Therefore, the second cooling material 42 can be cooled before it reaches the second phase transition temperature Tc2. That is, the cooling of the second cooling material 42 can be started before the temperature of the second cooling material 42 becomes constant due to the latent heat of the second cooling material 42. Thus, the battery 10, the first cooling material 41, and the second cooling material 42 can be highly responsively cooled.Moreover, the temperature of the cooling material layer 40 can be easily maintained between the first phase transition temperature Tc1 or higher and lower than the second phase transition temperature Tc2, and the temperature distribution in the battery 10 can be reduced more effectively.

[0067]

[0062] Furthermore, in Embodiment 1, until the temperatures detected by the inlet-side and outlet-side cooling material temperature sensors SN3, SN4 become lower than the first phase transition temperature Tc1, the coolant circulates through the cooling passage 60 by the pump 101. This makes it easier to maintain the temperature of the battery 10 constant by utilizing the latent heat of the first cooling material 41. Thus, the temperature distribution in the battery 10 can be more effectively reduced.

[0068] In Embodiment 1, the cooling system further includes the casing 50 arranged to cover the surface of the second cooling material 42 on the opposite side to the first cooling material 41, and the cooling passage 60 is arranged in the casing 50. This makes it possible to improve the degree of freedom in the arrangement of the cooling passage 60, and the cooling passages 60 can be arranged to achieve higher cooling efficiency. As a result, the temperature distribution in the battery 10 can be more effectively reduced.

[0069] In Embodiment 1, among the surfaces of the battery case 11, on a pair of second case surface portions 11b facing the flat surface portions 20b of the wound body 20 located on both sides in the minor axis direction, the cooling material layer 40 is provided in portions close to the terminals 31, 32, while the accessories (terminal box 13 and BMS 14) of the battery 10 are provided in portions remote from the terminals 31, 32. That is, among the surfaces of the battery case 11, the area of ​​the pair of second case surface portions 11b facing the flat surface portions 20b of the wound body 20 is larger compared to the other surface portions 11a, 11c of the surfaces of the battery case 11.Thus, the second case surface portions 11b have higher heat radiation efficiency compared to the other surface portions 11a, 11b. Accordingly, even if the cooling material layer 40 is not disposed in a part of the second case surface portions 11b, it is possible to sufficiently cool the battery 10. On the other hand, near the terminals 31, 32 of the battery 10, heat is easily generated, and the temperature tends to be higher. Therefore, by disposing the cooling material layer 40 in a part of the second case surface portions 11b near the terminals 31, 32, the battery 10 can be efficiently cooled.

[0070] Thus, even in a location such as the engine compartment of a vehicle where accessories are likely to be located, the temperature distribution in the battery 10 can be reduced.

[0071] Fig. 7 shows a modification of the cooling system in which a cooling system 150 is used in an intercooler 105 of a turbocharger. That is, in this modification, the cooling system of the battery 10 is not an independent cooling system and is in a state where the battery 10 is embedded in the cooling system 150 of the intercooler 105. According to this modification, since the existing cooling system 150 can be used, it is possible to minimize the space for providing the cooling system of the battery 10 to as small as possible. (Embodiment 2)

[0072] Hereinafter, Embodiment 2 will be described in detail with reference to the drawings. In the following description, the same parts as those in Embodiment 1 are denoted by the same reference numerals, and a detailed description thereof will be omitted.

[0073] In Embodiment 2, the configuration of the battery 10 is the same as that of Embodiment 1. On the other hand, in Embodiment 2, a cooling passage 260 is arranged differently from Embodiment 1. That is, as shown in Fig. 8, in Embodiment 2, a casing like that in Embodiment 1 is not provided, and the cooling passage 260 is formed in the second cooling material 42. The cooling passage 260 is formed by inserting a pipe or the like into the second cooling material 42.

[0074] Although the detailed illustration is omitted, like the cooling passage 60 of Embodiment 1, the cooling passage 260 includes a first channel in which the coolant flows toward the winding axis direction along the portion on the opposite side to the terminals in the major axis direction and then flows toward the terminal side in the major axis direction, and a second channel in which the coolant flows toward the terminal side in the major axis direction and then branches and flows toward the minor axis direction to surround the periphery of the terminals. The first channel and the second channel are configured such that the first channel and the second channel are separated on the inlet side, and then the first channel and the second channel join again on the outlet side.

[0075] The processing operation of the ECU 103 when cooling the battery 10 is the same as in Embodiment 1.

[0076] According to the configuration of Embodiment 2, since the second cooling material 42 can be directly cooled, it is possible to improve the cooling efficiency of the second cooling material 42. As a result, the cooling efficiency of the first cooling material 41 and the battery 10 can also be improved. Thus, the temperature distribution in the battery 10 can be more effectively reduced. (Embodiment 3)

[0077] Hereinafter, Embodiment 3 will be described in detail with reference to the drawings. In the following description, the same parts as those in Embodiments 1 and 2 are denoted by the same reference numerals, and a detailed description thereof will be omitted.

[0078] In Embodiment 3, the configuration of a battery 310 is different from that in Embodiments 1 and 2. Specifically, in Embodiment 3, as shown in Fig. 9, the battery 310 comprises a plurality of battery cells 370 (five battery cells 370 in Fig. 9). Each of the battery cells 370 includes a battery case 311 in the shape of a flat box, a wound body 320 housed in the battery case 311, and a positive electrode terminal 331 and a negative electrode terminal 332 provided in the battery case 311 and connected to the wound body 320. Since the detailed configuration of each of the battery cells 370 is the same as that of the battery 10 in Embodiments 1 and 2, a description thereof will be omitted.In the following description of the battery case 311, a pair of surface portions arranged on both sides in the direction of the major axis of the wound body 320 are referred to as the first case surface portions 311a, a pair of surface portions arranged on both sides in the direction of the minor axis of the wound body 320 are referred to as the second case surface portions 311b, and a pair of surface portions arranged on both sides in the direction of the winding axis of the wound body 320 are referred to as the third case surface portions 311c.

[0079] The battery cells 370 are arranged side by side in the direction of the minor axis of the wound body 320. The battery cells 370 are arranged such that positive electrode terminals 331 and negative electrode terminals 332 are alternately arranged in the parallel direction, so that they are easily connected in series. The battery cells 370 adjacent to each other in the parallel direction are electrically connected with a connecting member 333.

[0080] As this is Fig. As shown in FIG. 10, each of the battery cells 370 is covered with a cooling material layer 340. More specifically, among the plurality of battery cells 370, each of the battery cells 370 except for battery cells 370a on two end sides arranged on the end sides in the parallel direction is covered such that the entire surface portions except for the first surface portion 311a where the terminals 331, 332 are provided are covered with the cooling material layer 340. On the other hand, regarding the battery cells 370a on the end side, for the second surface portions 311b arranged on the outermost side in the parallel direction, the cooling material layer 340 is provided in the half portions close to the terminals 331, 332, while accessories of the battery 310 are arranged in the half portions away from the terminals 331, 332.One of the accessories of the battery 310 is the junction box 13, and the other is the BMS 14.

[0081] Similar to Embodiments 1 and 2, the cooling material layer 340 includes a first cooling material 341 that undergoes a phase transition from a solid phase to a liquid phase at the first phase transition temperature Tc1, and a second cooling material 342 that undergoes a phase transition from a solid phase to a liquid phase at the second transition temperature Tc2 higher than the first phase transition temperature Tc1.

[0082] In embodiment 3, the battery cells 370, which are adjacent to each other, share a second cooling material 342, as shown in Fig. 10. That is, the first cooling material 341 is provided for each of the battery cells 370, while the second cooling material 342 is provided independently at both ends in the parallel direction, but in the middle of the parallel direction, the second cooling material 342 is arranged to be interposed between two first cooling materials 341 in the parallel direction.

[0083] In Embodiment 3, the cooling material layer 340 and the battery 310 are jointly covered from the outside by a casing 350. As shown in Fig. 10, the housing 350 is not arranged between the battery cells 370, which are adjacent to each other in the parallel direction. A cooling passage 360 ​​is formed in a wall portion constituting the housing 350. The illustration of the housing 350 is shown in Fig. 9 is omitted. The housing 350 does not have to be in direct contact with the entire second cooling material 342, and a gap or spacing may be partially formed between the housing 350 and the second cooling material 342.

[0084] The processing operation of the ECU 103 when cooling the battery 310 is the same as in Embodiment 1.

[0085] In Embodiment 3, since the first cooling material 341 is also covered with or by the second cooling material 342, the temperature distribution in the battery 10 can be reduced. (Embodiment 4)

[0086] Hereinafter, Embodiment 4 will be described in detail with reference to the drawings. In the following description, the same parts as those in Embodiments 1 to 3 are denoted by the same reference numerals, and a detailed description thereof will be omitted.

[0087] In Embodiment 4, the configuration of a battery is the same as in Embodiment 3. On the other hand, in Embodiment 4, a cooling passage 460 is arranged differently from Embodiment 3. That is, as shown in Fig. As shown in FIG. 11, in Embodiment 4, a casing similar to that in Embodiment 3 is not provided, and the cooling passage 460 is formed in a second cooling material 442. The cooling passage 460 is formed by inserting a pipe or the like into the second cooling material 442.

[0088] Although not shown in detail, the cooling passage 460 is a passage which branches into a plurality of passages from an inlet portion, with the passages then joining or gathering at an outlet portion.

[0089] The processing operation of the ECU 103 when cooling the battery is the same as in Embodiment 1.

[0090] According to the configuration of Embodiment 4, it is possible to appropriately cool the entire second cooling material 442. As a result, the cooling efficiency of the first cooling material and the battery can be improved. Thus, the temperature distribution in the battery can be more effectively reduced. (Other embodiment)

[0091] The technology disclosed herein is not restricted or limited to the embodiments described above, and substitutions are possible without departing from the scope of the claims.

[0092] For example, in Embodiments 1 to 4 described above, of at least a part of the second surface portions 11b, 311b, the half portions remote from the terminals 31, 32, 331, 332 are not covered with the cooling material layers 40, 340. This is not a limitation, and all of the second surface portions 11b, 311b may be completely covered with the cooling material layers 40, 340.

[0093] Furthermore, in Embodiments 1 to 4, even if the surface temperature of each of the batteries 10, 310 is lower than the second phase transition temperature Tc2, the ECU 103 causes the pump 101 to circulate the coolant through the cooling passages 60, 260, 360, 460 when a judgment is made from the current heat value of the battery and the like that the surface temperature of the battery will reach the upper limit temperature Tmax. However, this control by the ECU 103 is not essential, and the ECU 103 may cause the pump 101 to circulate the coolant through the cooling passages 60, 260, 360, 460 only when the surface temperatures of the batteries 10, 310 become equal to or higher than the second phase transition temperature Tc2.

[0094] The embodiments described above are merely illustrative and should not be interpreted as limiting the scope of the present disclosure. The scope of the present disclosure is defined by the claims, and all modifications and changes that fall within the equivalent scope of the claims are within the scope of the present disclosure. [Industrial applicability]

[0095] The technology disclosed herein is useful as a cooling structure for a battery to be mounted in a vehicle. [List of reference symbols] 10, 310 battery 11, 311 Battery housing or casing 11a, 311a first surface section 11b, 311b second surface section 11c, 311c third surface section 13 Junction box (battery accessory) 14 Battery Management System BMS (battery accessory) 20, 320 wound body 21, 22 Current collector 23 Connecting part 20a curved or bent surface sections 20b flat surface sections 31, 331 positive electrode connection or connection of the positive electrode 32, 332 negative electrode connection or connection of the negative electrode 40, 340 Cooling material layer or layer 41, 341 first cooling material layer, first cooling material 20 42, 342, 442 second cooling material layer, second cooling material 50, 350 housing 60, 260, 360, 460 cooling passage 61 first channel 62 second channel 100, 150 cooling system 101 Pump 102 coolers 103 ECU, control unit 105 Intercooler 333 connecting link 370 battery cells 370a battery cell on the end side SN1 liquid temperature sensor SN2 Battery temperature sensor (battery temperature detection unit) SN3, SN4 Cooling material temperature sensor (cooling material temperature detection unit) SN5 Battery SOC Sensor Tc1 first phase transition temperature Tc2 second phase transition temperature Ta third predetermined temperature TMax upper limit temperature C heat capacity t0, t1, t2, t3, t4 time S1, S2, S3, S4, S5, S6, S7, S8, S9 step

Claims

[1] Cooling structure for a battery (10; 310) to be mounted in a vehicle, the cooling structure for a battery (10; 310) comprising: a cooling material layer (40; 340) including a first cooling material (41; 341) arranged at least partially along a surface of the battery (10; 310) and a second cooling material (42; 342; 442) arranged to at least partially cover a surface of the first cooling material (41; 341) on a side opposite the battery (10; 310); a cooling passage (60; 260; 360; 460) through which a coolant is circulated for cooling the cooling material layer (40; 340), a battery case (11; 311) in a flat box shape; a wound body (20; 320) accommodated in the battery case (11; 311), the wound body (20; 320) being formed by winding a sheet-like or plate-like wound body into a flat circular shape; and Electrode terminals (31, 32; 331, 332) provided on a respective one of a pair of first surface portions (11a; 311a) of surfaces of the battery case (11; 311) arranged on both sides in a direction of a main axis of the wound body (20; 320) and connected to the wound body (20; 320) in the battery case (11; 311), where each of the first and second cooling materials (41; 42; 341; 342; 442) is a cooling or cold storage material having a phase transition temperature at which a phase transition from a solid phase to a liquid phase takes place within a range lower than a predetermined temperature, a second phase transition temperature (Tc2), which is the phase transition temperature of the second cooling material (42; 342), is higher than a first phase transition temperature (Tc1), which is the phase transition temperature of the first cooling material (41; 341), the cooling material layer (40; 340) is a layer which at least partially covers the surfaces of the battery case (11; 311), and on a pair of second surface portions (11b; 311b) of the surfaces of the battery case (11; 311) facing surface portions of the wound body (20; 320) arranged on both sides in a direction of a minor axis, the cooling material layer (40; 340) is provided in a portion close to the electrode terminals (31, 32; 331, 332), while an accessory, namely a terminal box (13) and a battery management system BMS (14), of the battery (10; 310) is arranged in a portion remote from the electrode terminals (31, 32; 331, 332) without providing the cooling material layer (40; 340). [2] Cooling structure for a battery (310) to be mounted in a vehicle, wherein the cooling structure for a battery (310) comprises: a cooling material layer (340) including a first cooling material (341) arranged at least partially along a surface of the battery (310) and a second cooling material (342; 442) arranged to at least partially cover a surface of the first cooling material (341) on a side opposite the battery (310); and a cooling passage (360; 460) through which a coolant is circulated for cooling the cooling material layer (340), wherein the battery (310) includes a plurality of battery cells (370) and each of the battery cells (370) includes: a battery case (311) in a flat box shape; a wound body (320) accommodated in the battery case (311), the wound body (320) being formed by winding a sheet-like winding body into a flat circular shape; and Electrode terminals (331, 332) provided on a respective one of a pair of first surface portions (311a) of surfaces of the battery case (311) which are arranged on both sides in a direction of a main axis of the wound body (320) and are connected to the wound body (320) in the battery case (311), wherein each of the first and second cooling materials (341; 342; 442) is a cooling or cold storage material having a phase transition temperature at which a phase transition from a solid phase to a liquid phase takes place within a range lower than a predetermined temperature, a second phase transition temperature (Tc2), which is the phase transition temperature of the second cooling material (342), is higher than a first phase transition temperature (Tc1), which is the phase transition temperature of the first cooling material (341), the battery cells (370) are arranged side by side in a direction of a minor axis of the wound body (320), the cooling material layer (340) is a layer which at least partially covers the surfaces of the battery case (311), and in two end-side battery cells (370a) arranged on both end sides in a parallel direction among the battery cells (370), on each of surface portions arranged on outermost sides in the parallel direction, the cooling material layer (340) is provided in a portion close to the electrode terminals (331, 332), while an accessory, namely a terminal box (13) and a battery management system BMS (14), of the battery (310) is arranged in a portion away from the electrode terminals (331, 332) without providing the cooling material layer (340). [3] Cooling structure for a battery (10; 310) according to claim 1 or 2, further comprising: a battery temperature detection unit (SN2) which detects a temperature of the battery (10; 310); and / or a pump (101) for circulating the coolant through the cooling passage (60; 260; 360; 460), and / or the cooling passage (60; 260; 360; 460) is a passage which cools the second cooling material (42; 342; 442), and when the temperature detected by the battery temperature detection unit (SN2) is equal to or higher than the second phase transition temperature (Tc2), the pump (101) circulates the coolant through the cooling passage (60; 260; 360; 460). [4] A cooling structure for a battery (10; 310) according to claim 3, further comprising a cooling material temperature detecting unit (SN3, SN4) which detects a temperature of the first cooling material (41, 341), wherein the pump (101) circulates the coolant through the cooling passage (60; 260; 360; 460) until the temperature detected by the cooling material temperature detection unit (SN3, SN4) becomes lower than the first phase transition temperature (Tc1). [5] A cooling structure for a battery (10; 310) according to claim 3 or 4, further comprising a casing (50; 350) arranged to at least partially cover a surface of the second cooling material (42; 342; 442) on an opposite side to the first cooling material (41; 341), wherein the cooling passage (60; 260; 360; 460) is arranged in a wall section which represents the housing (50; 350). [6] A method of providing a cooling structure for a battery (10; 310), comprising: providing a cooling material layer (40; 340) including a first cooling material (41; 341) arranged at least partially along a surface of the battery (10; 310) and a second cooling material (42; 342; 442) arranged to at least partially cover a surface of the first cooling material (41; 341) on a side opposite the battery (10; 310); providing a cooling passage (60; 260; 360; 460) through which a coolant is circulated for cooling the cooling material layer (40; 340), providing a battery case (11; 311) in a flat box shape; providing a wound body (20; 320) accommodated in the battery case (11; 311), the wound body (20; 320) being formed by winding a sheet-like or plate-like winding body into a flat circular shape; and providing electrode terminals (31, 32; 331, 332) which are arranged on a respective one of a pair of first surface portions (11a; 311a) of surfaces of the battery case (11; 311), which are arranged on both sides in a direction of a main axis of the wound body (20; 320) and are connected to the wound body (20; 320) in the battery case (11; 311), where each of the first and second cooling materials (41; 42; 341; 342; 442) is a cooling or cold storage material having a phase transition temperature at which a phase transition from a solid phase to a liquid phase takes place within a range lower than a predetermined temperature, and a second phase transition temperature (Tc2), which is the phase transition temperature of the second cooling material (42; 342), is higher than a first phase transition temperature (Tc1), which is the phase transition temperature of the first cooling material (41; 341), the cooling material layer (40; 340) is a layer which at least partially covers the surfaces of the battery case (11; 311), and on a pair of second surface portions (11b; 311b) of the surfaces of the battery case (11; 311) facing surface portions of the wound body (20; 320) arranged on both sides in a direction of a minor axis, the cooling material layer (40; 340) is formed in a portion close to the electrode terminals (31, 32; 331, 332), while an accessory, namely a terminal box (13) and a battery management system BMS (14), of the battery (10; 310) is arranged in a portion remote from the electrode terminals (31, 32; 331, 332) without providing the cooling material layer (40; 340). [7] A method of providing a cooling structure for a battery (310), comprising: providing a cooling material layer (340) which includes a first cooling material (341) arranged at least partially along a surface of the battery (310) and a second cooling material (42; 342; 442) arranged to at least partially cover a surface of the first cooling material (341) to cover on a side opposite to the battery (310); providing a cooling passage (360; 460) through which a coolant is circulated for cooling the cooling material layer (340), wherein the battery (310) includes a plurality of battery cells (370) and each of the battery cells (370) contains: a battery case (311) in a flat box shape; a wound body (320) accommodated in the battery case (311), the wound body (320) being formed by winding a sheet-like winding body into a flat circular shape; and Electrode terminals (331, 332) formed on a respective one of a pair of first surface portions (311a) of surfaces of the battery case (311), which are arranged on both sides in a direction of a main axis of the wound body (320) and are connected to the wound body (320) in the battery case (311), where each of the first and second cooling materials (342; 442) is a cooling or cold storage material having a phase transition temperature at which a phase transition from a solid phase to a liquid phase takes place within a range lower than a predetermined temperature, and a second phase transition temperature (Tc2), which is the phase transition temperature of the second cooling material (342), is higher than a first phase transition temperature (Tc1), which is the phase transition temperature of the first cooling material (341), the battery cells (370) are arranged side by side in a direction of a minor axis of the wound body (320), the cooling material layer (340) is a layer which at least partially covers the surfaces of the battery case (311), and in two end-side battery cells (370a) arranged on both end sides in a parallel direction among the battery cells (370), on each of surface portions arranged on outermost sides in the parallel direction, the cooling material layer (340) is formed in a portion close to the electrode terminals (331, 332), while an accessory, namely a terminal box (13) and a battery management system BMS (14), of the battery (310) is arranged in a portion remote from the electrode terminals [8] The method of claim 6 or 7, further comprising: providing a battery temperature detection unit (SN2) which detects a temperature of the battery (10; 310); and / or providing a pump (101) for circulating the coolant through the cooling passage (60; 260; 360; 460), and / or the cooling passage (60; 260; 360; 460) is formed as a passage which cools the second cooling material (42; 342; 442). [9] The method according to claim 8, further comprising providing a cooling material temperature detection unit (SN3, SN4) which detects a temperature of the first cooling material (41, 341).

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