Battery pack cooling structure

Abstract

To provide a battery pack cooling structure which effectively cools a battery module by using a cooling fluid and a cooling refrigerant.SOLUTION: A battery pack cooling structure 16 includes: a battery pack case 18 in which a battery module 17 is stored; a cooling fluid passage 20 which is disposed near the battery module 17 and in which a cooling fluid 19 for cooling the battery module 17 flows; a refrigerant passage 21 which is arranged to conduct heat exchange with the cooling fluid 19 flowing through the cooling fluid passage 20 and be exposed to an internal space of the battery pack case 18 and in which a refrigerant flows; and a water suction part 25 which is disposed contacting with the refrigerant passage 21 and may suction water.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a battery pack cooling structure, and more particularly to a battery pack cooling structure that cools a battery module using a cooling fluid and a cooling refrigerant. [Background technology]

[0002] An electric vehicle is equipped with a storage battery that stores electric power for driving. The temperature of this storage battery is managed and regulated to be within a certain temperature range. That is, the temperature of the storage battery is raised so that the temperature does not fall below a lower limit temperature, and is cooled so that the temperature of the storage battery does not exceed an upper limit temperature. In addition, the output from the storage battery may be limited depending on the temperature condition of the storage battery.

[0003] In a battery mounted on a vehicle, condensation may occur on the battery or on components disposed in the vicinity of the battery. The following Patent Documents 1 and 2 describe inventions that deal with such condensation. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2010-129392 A [Patent Document 2] JP 2012-94376 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the inventions described in the above-mentioned patent documents leave room for improvement in the method of dealing with moisture that is generated when adjusting the temperature of the battery.

[0006] That is, in the invention described in the cited document 1, the water condensation that occurs is absorbed by a water supply layer, but no consideration is given to the moisture that occurs in the space that the battery is stored in. Also, in the invention described in the above-mentioned patent document 2, a water guide path is required to collect the condensed water, which makes the countermeasure against condensation water complicated and further increases costs.

[0007] The present invention has been made in consideration of the above problems, and an object of the present invention is to provide a battery pack cooling structure that effectively cools battery modules using a cooling fluid and a cooling refrigerant. [Means for solving the problem]

[0008] The battery pack cooling structure of the present invention comprises: a battery pack case for accommodating a battery module; a cooling fluid path disposed in the vicinity of the battery module and through which a cooling fluid for cooling the battery module flows; a coolant path for exchanging heat with the cooling fluid flowing through the cooling fluid path and disposed so as to be exposed to an inner space of the battery pack case and through which a coolant flows; and a water absorption section made of a water-absorbent material and configured to absorb condensation occurring in the coolant path; The cooling fluid flowing through the cooling fluid passage is a liquid, and the refrigerant flowing through the refrigerant passage is a refrigerant used in a vapor compression refrigeration cycle. Effect of the Invention

[0013] According to the battery pack cooling structure of the present invention, it is possible to provide a battery pack cooling structure that effectively cools the battery modules by using a cooling fluid and a cooling refrigerant. [Brief description of the drawings]

[0018] [Figure 1] 1 is a perspective view showing a vehicle equipped with a battery pack cooling structure according to an embodiment of the present invention. [Diagram 2] 1 is a connection diagram showing a battery pack cooling structure according to an embodiment of the present invention. [Diagram 3] 1 is a cross-sectional view showing a battery pack cooling structure according to an embodiment of the present invention. [Figure 4]1A and 1B are diagrams showing a battery pack cooling structure according to another embodiment of the present invention, in which (A) is a cross-sectional view, and (B) is a perspective view showing the cooling fluid and the refrigerant passages. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] A battery pack cooling structure 16 according to an embodiment of the present invention will be described in detail below with reference to the drawings. In the following description, the front, rear, up, down, left and right directions are used, and the left and right directions refer to the left and right directions when the vehicle 10 is viewed from the rear. Furthermore, in the following description, the same members are generally given the same reference numerals, and repeated description will be omitted.

[0020] 1 is a perspective view showing a vehicle 10 equipped with a battery pack cooling structure 16. The vehicle 10, such as an automobile or train, is equipped with a battery pack 26 for supplying power to a motor and various electrical components. The vehicle 10 is, for example, an EV (Electrical Vehicle), an HEV (Hybrid Electrical Vehicle), a PHEV (Plug-in Hybrid Electrical Vehicle), or the like.

[0021] For convenience of explanation, a rear gate covering the rear end of the body of the vehicle 10 is omitted in Fig. 1. A rear seat 13 is provided at the rear of the passenger compartment of the vehicle 10, and a rear floor 12 is provided further behind the rear seat 13. A battery pack 26 (not shown in the figures) (described later) is provided in a storage space 11 below the rear floor 12. The battery pack 26 also includes a battery pack cooling structure 16 (described later).

[0022] Furthermore, the battery pack 26 and the battery pack cooling structure 16 are not limited to being disposed below the rear floor 12, but may also be disposed below a front floor (not shown) on which the driver's seat and passenger seat are located.

[0023] 2 is a connection diagram showing the battery pack cooling structure 16. The battery pack cooling structure 16 has an arithmetic and control unit 23, a battery temperature detection unit 22, an ambient temperature detection unit 27, a memory unit 14, and a refrigeration cycle 24.

[0024] The calculation control unit 23 is, for example, a CPU, and its input terminals are connected to the battery temperature detection unit 22, the ambient temperature detection unit 27, and the memory unit 14, and its output terminals are connected to the refrigeration cycle 24. The calculation control unit 23 controls the operation of the refrigeration cycle 24 based on input information input from the ambient temperature detection unit 27, the battery temperature detection unit 22, and the memory unit 14.

[0025] The battery temperature detection unit 22 detects the temperature of the battery module 17 (described later), and inputs the detection result to the calculation control unit 23 .

[0026] The ambient temperature detection unit 27 detects the temperature around the battery pack 26 and the vehicle 10 , and inputs the detection result to the calculation control unit 23 .

[0027] The storage unit 14 is a RAM or ROM, and stores programs, parameters, and the like for the battery pack cooling structure 16 to operate.

[0028] The refrigeration cycle 24 is a vapor compression refrigeration cycle that cools the refrigerant flowing through the refrigerant passage 21 described below. The refrigeration cycle 24 may be configured as a dedicated device for cooling the battery module 17. Furthermore, the refrigeration cycle 24 may also serve as an air conditioning device for cooling the passenger compartment of the vehicle 10.

[0029] FIG. 3 is a cross-sectional view showing a battery pack 26 having a battery pack cooling structure 16.

[0030] The battery pack 26 has a battery module 17 and a battery pack cooling structure 16 housed inside a battery pack case 18.

[0031] The battery module 17 supplies current to a motor that provides driving force to the body of the vehicle 10. A secondary battery such as a nickel-metal hydride battery or a lithium-ion battery can be used as the battery module 17. Although not shown here, the battery module 17 is composed of a plurality of battery cells arranged in a stack.

[0032] The battery pack cooling structure 16 has a battery pack case 18 , a cooling fluid path 20 , a refrigerant path 21 , and a water absorption section 25 .

[0033] The battery pack case 18 is a substantially box-shaped container that houses the battery module 17. The battery pack case 18 is made of a metal plate or a synthetic resin plate formed into a predetermined shape. The inside of the battery pack case 18 is substantially sealed.

[0034] The cooling fluid path 20 is disposed near the battery module 17, and a cooling fluid 19 for cooling the battery module 17 flows through the cooling fluid path 20. The cooling fluid 19 is disposed so as to exchange heat with each battery cell constituting the battery module 17. As the cooling fluid 19 circulating inside the cooling fluid path 20, a liquid such as water can be used. Here, the cooling fluid path 20 is disposed below the battery module 17.

[0035] Here, a heat transfer material 15 can be interposed between the cooling fluid path 20 and the battery module 17. The heat transfer material 15 is a sheet-like member with excellent heat transfer properties, and for example, a resin material with high thermal conductivity, a grease-like member, or the like can be used. By using the heat transfer material 15, it is possible to promote heat exchange between the battery module 17 and the cooling fluid path 20. Here, the battery pack 26 can also be configured without using the heat transfer material 15.

[0036] The refrigerant path 21 is configured to exchange heat with the cooling fluid 19 flowing through the cooling fluid path 20. A refrigerant used in a vapor compression refrigeration cycle flows through the inside of the refrigerant path 21. The vapor compression refrigeration cycle has a compressor, a condenser, an expansion means, and an evaporator, and the refrigerant circulates between these components. A refrigerant in a low temperature state that has passed through the expansion means flows through the refrigerant path 21. In this way, heat exchange occurs between the cooling fluid 19 flowing through the cooling fluid path 20 and the refrigerant flowing through the refrigerant path 21, and the cooling fluid 19 can be effectively cooled.

[0037] As described above, the battery module 17 is cooled using the cooling fluid path 20, and further, the cooling fluid 19 flowing through the cooling fluid path 20 is cooled by the refrigerant path 21, thereby making it possible to effectively and uniformly cool the battery module 17.

[0038] Furthermore, the coolant path 21 is disposed so as to be exposed to the space inside the battery pack case 18. When the coolant flows inside the coolant path 21, the surface temperature of the coolant path 21 becomes lower than the surface temperatures of the battery module 17, the cooling fluid path 20, and the water absorption section 25. That is, the surface temperature of the coolant path 21 is the lowest.

[0039] The water absorption part 25 is configured to absorb condensation occurring in the refrigerant passage 21. Here, the water absorption part 25 is arranged so as to be in contact with the refrigerant passage 21. More specifically, when the refrigerant passage 21 and the water absorption part 25 are viewed from above, the water absorption part 25 is arranged so as to surround the refrigerant passage 21. As a material for the water absorption part 25, a material capable of absorbing water, such as a foamed resin or diatomaceous earth, can be used.

[0040] In addition, the water absorption section 25 is disposed at a position farther from the battery module 17 than the coolant passage 21. In this manner, the moisture absorbed by the water absorption section 25 can be separated from the battery module 17.

[0041] The battery pack cooling structure 16 configured as above operates as follows.

[0042] First, when the temperature of the battery module 17 detected by the battery temperature detection unit 22 reaches a certain temperature or higher, for example, 40° C. or higher, the calculation control unit 23 operates a pump (not shown) to circulate the cooling fluid 19 inside the cooling fluid path 20. In this way, heat is exchanged between each battery cell constituting the battery module 17 and the cooling fluid 19, and the battery module 17 can be cooled.

[0043] By absorbing heat from the battery modules 17, the temperature of the cooling fluid 19 rises inside the cooling fluid path 20. Therefore, the calculation control unit 23 circulates the cooling fluid inside the cooling fluid path 21. In this way, heat exchange occurs between the cooling fluid circulating inside the cooling fluid path 21 and the cooling fluid 19 circulating inside the cooling fluid path 20, and the cooling fluid 19 can be cooled. Therefore, the cooling fluid 19 can be effectively cooled by the cooling fluid circulating through the cooling fluid path 21, and further the battery modules 17 can be effectively cooled.

[0044] When the surface temperature of the coolant path 21 drops due to the coolant flowing through the coolant path 21, moisture contained in the air inside the battery pack case 18 preferentially condenses on the surface of the coolant path 21. Thus, the condensation on the surface of the coolant path 21 can reduce the humidity inside the battery pack case 18, preventing condensation from occurring on the surface of the battery module 17, and further preventing defects in the battery module 17 due to the condensation.

[0045] The moisture condensed on the surface of the coolant path 21 is absorbed by the water absorption section 25. In this manner, the condensation occurring in the coolant path 21 can be prevented from reaching the battery module 17.

[0046] Thereafter, when the temperature of the battery module 17 detected by the battery temperature detection unit 22 falls below a certain temperature, for example, below 40° C., the calculation control unit 23 stops the pump, for example, to stop the circulation of the cooling fluid 19 inside the cooling fluid path 20. Furthermore, the flow of the cooling fluid 19 inside the cooling fluid path 21 is stopped.

[0047] Here, when the outside air temperature detected by the ambient temperature detection unit 27 is a low temperature such as a temperature below a predetermined value (for example, below 0°C), the calculation control unit 23 draws the refrigerant out of the refrigerant path 21. For example, the refrigerant is drawn out of the refrigerant path 21 by operating a pump (not shown) and the inside of the refrigerant path 21 is made into a substantially vacuum state. In this way, the refrigerant path 21 functions as a heat insulating layer that insulates the battery module 17 from the outside, and a drop in the temperature of the battery module 17 can be suppressed.

[0048] Here, the flow rate of the cooling fluid 19 inside the cooling fluid path 20 can be adjusted by the calculation control unit 23. Specifically, by increasing the flow rate of the cooling fluid 19 by the calculation control unit 23, the temperature of the battery modules 17 can be made uniform, that is, the temperature of the battery modules 17 can be made uniform. On the other hand, by decreasing the flow rate of the cooling fluid 19 by the calculation control unit 23, the battery modules 17 can be cooled.

[0049] FIG. 4 shows a battery pack cooling structure 16 according to another embodiment of the present invention, in which FIG. 4(A) is a cross-sectional view showing a battery pack 26, and FIG. 4(B) is a perspective view showing the cooling fluid 19 and the refrigerant path 21.

[0050] 4(A), the coolant path 21 is disposed in a lower portion of the cooling fluid path 20. A portion of the coolant path 21 is in contact with the air inside the battery pack case 18. In this manner, as described above, moisture contained in the air inside the battery pack case 18 is condensed on the surface of the coolant path 21, and the occurrence of condensation on the surface of the battery module 17 can be suppressed.

[0051] 4(B), the cooling fluid path 20 is formed as an elongated member having a longitudinal direction along the longitudinal direction of the battery module 17 (the direction in which the battery cells constituting the battery module 17 are stacked). The refrigerant path 21 extends along the longitudinal direction of the cooling fluid path 20 (the direction in which the battery cells constituting the battery module 17 are stacked). In this manner, the temperature difference of the cooling fluid 19 inside the cooling fluid path 20 can be reduced, and the temperature difference of the battery module 17 can be reduced. Here, the lower surface of the cooling fluid path 20 is an uneven surface, and the upper surface of the refrigerant path 21 comes into planar contact with the uneven surface, thereby facilitating heat exchange between the cooling fluid path 20 and the refrigerant path 21.

[0052] Furthermore, the water absorption portion 25 is disposed on the lower surface of the refrigerant passage 21. In this manner, the condensation occurring in the refrigerant passage 21 can be reliably captured by the water absorption portion 25.

[0053] The above-described embodiment can provide the following main effects.

[0054] According to the present embodiment described above, the battery modules 17 are cooled by the cooling fluid 19 flowing through the cooling fluid path 20, and the cooling fluid 19 is cooled by the refrigerant flowing through the refrigerant path 21, thereby making it possible to cool the battery modules 17. Furthermore, it is possible to prevent variations in temperature of the battery modules 17, and to prevent early deterioration of the charging or discharging characteristics of the battery modules 17.

[0055] Furthermore, even if the humidity inside the battery pack case increases, moisture condenses on the surface of the coolant path 21, thereby preventing condensation from occurring in the battery module 17. Furthermore, by arranging the water absorption section 25 near the coolant path 21, moisture condensed in the coolant path 21 is absorbed by the water absorption section 25, preventing the moisture from reaching the battery module 17. Furthermore, the battery pack cooling structure 16 can be configured without a cooling device (e.g., a chiller) for cooling the cooling fluid 19. Moreover, since the cooling fluid path 20 and the coolant path 21 are housed inside the battery pack case 18, the overall configuration of the battery pack 26 can be simplified.

[0056] Furthermore, according to this embodiment, by arranging the water absorption section 25 so as to surround the coolant passage 21, the water that condenses on the surface of the coolant passage 21 can be reliably absorbed by the water absorption section 25.

[0057] Furthermore, according to this embodiment, by extracting the refrigerant from the refrigerant path 21 and creating a substantial vacuum inside the refrigerant path 21, the refrigerant path 21 functions as a thermal insulator, and excessive temperature drops in the battery modules 17 can be suppressed.

[0058] Furthermore, according to this embodiment, by arranging the water absorption section 25 at a position farther away from the battery module 17 than the coolant path 21, it is possible to prevent moisture condensed in the coolant path 21 from reaching the battery module 17.

[0059] Although the embodiment of the present invention has been described above, the present invention is not limited to this embodiment, and modifications can be made without departing from the scope of the present invention. In addition, the above-described embodiments can be combined with each other.

[0060] 3, a heat transfer sheet may be interposed between the cooling fluid path 20 and the refrigerant path 21. In this way, heat dissipation from the battery module 17 can be further promoted. The invention that can be understood from the above-described embodiment will be described below together with its effects. The battery pack cooling structure of the present invention is characterized by comprising a battery pack case in which a battery module is housed, a cooling fluid path arranged near the battery module and through which a cooling fluid for cooling the battery module flows, a refrigerant path arranged so as to exchange heat with the cooling fluid flowing through the cooling fluid path and exposed to the inner space of the battery pack case, through which a refrigerant flows, and a water absorption part made of a material capable of absorbing water and configured to absorb condensation generated in the refrigerant path. According to the battery pack cooling structure of the present invention, the battery module is cooled by the cooling fluid flowing through the cooling fluid path, and the cooling fluid is cooled by the refrigerant flowing through the refrigerant path, so that the battery module can be evenly cooled. Furthermore, even if the humidity inside the battery pack case increases, moisture condenses on the surface of the refrigerant path, thereby reducing the humidity (moisture) in the air inside the battery pack, and condensation on the battery module or cell can be suppressed. Furthermore, by arranging the water absorption part near the refrigerant path, the moisture condensed in the refrigerant path is absorbed by the water absorption part, and the moisture can be prevented from reaching the battery module or cell. In the battery pack cooling structure of the present invention, the water absorption part is disposed so as to surround the coolant passage. According to the battery pack cooling structure of the present invention, by disposing the water absorption part so as to surround the coolant passage, the water that condenses on the surface of the coolant passage can be reliably absorbed by the water absorption part. In addition, the battery pack cooling structure of the present invention further includes an ambient temperature detection unit that detects the ambient temperature, and an arithmetic and control unit, and the arithmetic and control unit draws the refrigerant from the refrigerant path when the temperature detected by the ambient temperature detection unit is equal to or lower than a predetermined value. According to the battery pack cooling structure of the present invention, by drawing the refrigerant from the refrigerant path and making the inside of the refrigerant path into a substantially vacuum state, the refrigerant path functions as a thermal insulator, and excessive temperature drop of the battery module can be suppressed. In the battery pack cooling structure of the present invention, the water absorption section is disposed at a position farther from the battery module than the coolant path is. By disposing the water absorption section at a position farther from the battery module than the coolant path is, it is possible to prevent moisture condensed in the coolant path from reaching the battery module. In addition, in the battery pack cooling structure of the present invention, the battery module has a plurality of battery cells arranged in a stack, the cooling fluid path is arranged in an elongated manner along the direction in which the battery cells are stacked, and the refrigerant path extends along the direction in which the battery cells are stacked. According to the battery pack cooling structure of the present invention, the cooling fluid path is arranged in an elongated manner along the direction in which the battery cells are stacked, and the refrigerant path extends along the direction in which the battery cells are stacked, thereby making it possible to uniformly cool the battery cells. [Explanation of symbols]

[0061] 10 Vehicles 11. Storage Space 12 Rear floor 13 Rear seat 14 Storage section 15 Heat Transfer Materials 16 Battery pack cooling structure 17 Battery Module 18 Battery pack case 19 Cooling fluid 20 Cooling fluid path 21 Coolant path 22 Battery temperature detection section 23 Calculation and control unit 24 Refrigeration Cycle 25 Water absorption part 26 Battery Pack 27 Ambient temperature detector

Claims

1. a battery pack case in which the battery module is housed; a cooling fluid path disposed in the vicinity of the battery module and through which a cooling fluid for cooling the battery module flows; a coolant path that exchanges heat with the cooling fluid flowing through the cooling fluid path and is disposed so as to be exposed to an inner space of the battery pack case, the coolant path through which a coolant flows; A water absorbing portion is made of a water absorbing material and configured to absorb condensation generated in the refrigerant passage. the cooling fluid flowing through the cooling fluid passage is a liquid; a cooling structure for a battery pack, the cooling medium flowing through the cooling medium passage being a cooling medium used in a vapor compression refrigeration cycle;

2. The cooling fluid path and the refrigerant path are arranged on a lower side of the battery module, 2. The battery pack cooling structure according to claim 1, wherein the cooling fluid path is disposed between the battery module and the refrigerant path.

3. The lower surface of the cooling fluid path is provided with an uneven surface, 3. The battery pack cooling structure according to claim 2, wherein an upper surface of the coolant passage is in surface contact with the uneven surface.

4. A battery pack case in which a battery module is stored; a cooling fluid path disposed in the vicinity of the battery module and through which a cooling fluid for cooling the battery module flows; a coolant path that exchanges heat with the cooling fluid flowing through the cooling fluid path and is disposed so as to be exposed to an inner space of the battery pack case, the coolant path through which a coolant flows; A water absorbing portion made of a water absorbing material and configured to absorb condensation generated in the refrigerant passage; An ambient temperature detection unit that detects the ambient temperature; A calculation control unit; The battery pack cooling structure is characterized in that the calculation control unit extracts the refrigerant from the refrigerant path when the temperature detected by the ambient temperature detection unit is equal to or lower than a predetermined value.

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