JP2020009690A - Power storage device - Google Patents

Abstract

To provide a power storage device capable of improving the cooling performance, while restraining increase in cooling medium amount.SOLUTION: A power storage device 1 comprises a power storage module 10 including multiple power storage cells arranged in a first direction, and having a pair of sides facing each other in a second direction orthogonal to the first direction, and a cooling mechanism for cooling at least one of a pair of faces. The cooling mechanism includes a coolant passage 40 provided to elongate in the first direction, and a heat pipe 50 abutting on at least one of the pair of faces. The heat pipe 50 has a comb shape including a stem extending continuously in the first direction, and multiple branch parts branched from the stem and extending in a third direction orthogonal to the first and second directions, where the multiple branch parts 52 abuts on at least one of the pair of faces, and abuts on the coolant passage 40.SELECTED DRAWING: Figure 2

Description

  The present disclosure relates to a power storage device that can cool a power storage module.

  Conventionally, various power storage devices capable of cooling a power storage module have been proposed. For example, in a power storage device disclosed in US Patent Application Publication No. 2015/0044540 (Patent Document 1), a linear cooling line disposed below the power storage module is directed toward the power storage module by a pressing member. Pressed.

US Patent Application Publication No. 2015/0044540

  When a plurality of power storage cells arranged in one direction are restrained by a restraining band or the like to form a power storage module, some of the power storage cells may be shifted in a height direction. In this case, a step is formed between the storage cell shifted in the height direction and the storage cell adjacent thereto.

  When the cooling line has a shape extending linearly, the degree of freedom of deformation of the cooling line is low, and it is difficult to deform the cooling line so as to follow the step. In such a case, thermal contact between some of the storage cells and the cooling line becomes insufficient, and the cooling performance decreases. Therefore, it is conceivable to meander the cooling line in order to increase the degree of freedom of the deformation of the cooling line.

  However, when the cooling line is meandering, the length of the refrigerant flow path becomes longer, and the amount of the refrigerant flowing through the cooling line increases. In this case, as the refrigerant increases, equipment such as a receiver, an accumulator, and a muffler may be provided to store the refrigerant, which increases the manufacturing cost.

  The present disclosure has been made in view of the above problems, and an object of the present disclosure is to provide a power storage device that can improve cooling performance while suppressing an increase in the amount of refrigerant.

  A power storage device according to an embodiment of the present disclosure includes a plurality of power storage cells arranged in a first direction, a power storage module having a pair of surfaces facing each other in a second direction orthogonal to the first direction, and at least one of the pair of surfaces. And a cooling mechanism for cooling one of them. The cooling mechanism includes a refrigerant flow path provided to extend along the first direction, and a heat pipe in contact with at least one of the pair of surfaces. The heat pipe includes a trunk extending continuously along the first direction, and a plurality of branches branching from the trunk and extending in a third direction orthogonal to the first direction and the second direction. It has a comb shape. The plurality of branch portions abut on at least one of the pair of surfaces and abut on the refrigerant flow path.

  According to the above configuration, since the heat pipe has a comb-teeth shape, the degree of freedom of deformation of the plurality of branches forming the comb teeth increases. Therefore, each of the plurality of branch portions can be easily brought into contact with the side surface of the power storage module. Thus, the plurality of branches can reliably remove heat from the power storage module. Further, by the plurality of branch portions abutting on the coolant channel, the working fluid in the heat pipe vaporized by the heat from the power storage module can be cooled and liquefied. Thereby, the power storage module can be repeatedly cooled.

  In this manner, by bringing each of the plurality of branch portions into contact with the side surface of the power storage module, the power storage module can be reliably cooled, and the cooling performance can be improved.

  Further, since the refrigerant flow path is provided so as to extend along the first direction, the refrigerant flow path length increases as compared with the case where the refrigerant flow path is meandering or formed in a ladder shape. Can be suppressed. As described above, the working fluid in the heat pipe is cooled by the coolant flow path while the increase in the coolant flow path length is suppressed, so that the increase in the amount of the coolant in the cooling system can be suppressed.

  According to the present disclosure, it is possible to provide a power storage device that can improve cooling performance while suppressing an increase in the amount of refrigerant.

1 is a schematic diagram of a vehicle equipped with a power storage device according to an embodiment. FIG. 3 is a cross-sectional view of a power storage device according to an embodiment. It is a figure showing the heat pipe concerning an embodiment. FIG. 4 is a sectional view taken along the line IV-IV shown in FIG. 2.

  Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the following embodiments, the same or common portions are denoted by the same reference numerals in the drawings, and description thereof will not be repeated.

  FIG. 1 is a schematic diagram showing a vehicle equipped with a power storage device according to the embodiment. With reference to FIG. 1, a vehicle 2 equipped with a power storage device 1 according to the embodiment will be described.

  As shown in FIG. 1, vehicle 2 includes a power storage device 1, a PCU (Power. Control Unit) 4, rotating electric machines 5 and 6, an engine (not shown), and a power split mechanism (not shown).

  Power storage device 1 is a rechargeable secondary battery. Power storage device 1 supplies the stored power to PCU 4, and rotating electric machine 5 is driven by the power supplied to PCU 4, and vehicle 2 runs. The rotating electric machine 6 mainly functions as a generator, and the electric power generated by the rotating electric machine 6 is supplied to the power storage device 1 through the PCU 4.

  The vehicle to which the power storage device 1 according to the present disclosure is applied can be applied not only to a hybrid vehicle but also to an electric vehicle or a fuel cell vehicle. Also in a hybrid vehicle, the present invention can be applied to any of a series system, a parallel system, and a series-parallel system. In addition, the present invention is not limited to a hybrid vehicle provided with two rotating electric machines, and can be applied to a so-called one-motor hybrid provided with one rotating electric machine.

  In the example shown in FIG. 1, power storage device 1 is mounted in vehicle 2. The mounting position of power storage device 1 is not limited to the vehicle interior, and may be disposed outside the vehicle, for example, on the lower surface of the floor panel of vehicle 2.

  FIG. 2 is a cross-sectional view of the power storage device according to the embodiment. Referring to FIG. 2, power storage device 1 according to Embodiment 1 will be described.

  As shown in FIG. 2, power storage device 1 also includes battery module 10, case 11, restraint 21, and cooling mechanism 30 as power storage modules.

  The battery module 10 includes a plurality of battery cells 20 arranged in a first direction (DR1 direction in the figure). The battery cell is, for example, a secondary battery such as a nickel metal hydride battery or a lithium ion battery. The cell has, for example, a square shape. The unit cell is not limited to the square shape, but may be a cylindrical shape. The secondary battery may use a liquid electrolyte or may use a solid electrolyte.

  The battery module 10 includes a pair of end surfaces 10a facing each other in a first direction, a pair of side surfaces 10b facing a second direction (DR2 direction in the drawing) orthogonal to the first direction, and a first direction and a second direction. It has a pair of main surfaces 10c that face each other in a third direction (the DR3 direction in the figure) orthogonal to the first direction.

  The first direction is, for example, a front-back direction of the vehicle. The second direction is, for example, the width direction of the vehicle. The third direction is, for example, a vertical direction.

  Case 11 houses battery module 10, restraint 21, and at least a part of cooling mechanism 30.

  The restraining device 21 includes an end plate 25 and an end plate 26, and a restraining band 27. The end plate 25 is provided at one end of the battery module 10 in the first direction, and the end plate 26 is provided at the other end of the battery module 10 in the first direction. The restriction band 27 connects the end plate 25 and the end plate 26.

  The plurality of battery cells 20 are restrained by restraints 21, and specifically, are pressed and fixed by end plates 25 and 26.

  The cooling mechanism 30 mainly cools the battery module 10. The cooling mechanism 30 cools the battery module 10 by cooling at least one of the pair of side surfaces 10b.

  The cooling mechanism 30 includes a coolant channel 40 and a heat pipe 50. The coolant channel 40 is provided to extend along the first direction. Refrigerant flow path 40 is connected to a cooling cycle in an air conditioner that adjusts the temperature in the vehicle compartment, for example. The coolant flows inside the coolant channel 40.

  The coolant channel 40 is disposed between the side surface of the case 11 facing the side surface 10 b of the battery module 10 and the heat pipe 50. The coolant flow path 40 is disposed apart from the bottom surface of the case 11. The coolant flow path 40 contacts the heat pipe 50 from outside the heat pipe 50.

  The heat pipe 50 contacts at least one of the pair of side surfaces 10 b of the battery module 10. The heat pipe 50 is formed of a metal material having high thermal conductivity. A working fluid such as R1234ze is sealed inside the heat pipe 50. The heat pipe 50 is formed by a roll bonding method so that a sealing portion 53 described later is formed inside.

  FIG. 3 is a diagram illustrating a heat pipe according to the embodiment. As shown in FIG. 3, the heat pipe 50 has a comb shape. The heat pipe 50 is provided such that a comb tooth portion is in contact with a surface parallel to the first direction of the battery module 10, and is provided such that the coolant passage 30 is in contact with a tip end of the comb tooth. The heat pipe 50 includes a trunk portion 51, a plurality of branch portions 52, and a sealing portion 53.

  The trunk 51 is provided at one end (lower end) of the heat pipe 50 in the third direction. The trunk 51 extends continuously along the first direction. The plurality of branches 52 branch from the trunk 51 and extend in the third direction. Specifically, the plurality of branch portions 52 extend upward from the trunk portion 51. The plurality of branches 52 are arranged in the first direction so as to be separated from each other. A gap is formed between the adjacent branch portions 52. The plurality of branches 52 are provided so as to correspond to the plurality of battery cells 20.

  The enclosing portion 53 is provided inside the heat pipe 50. The working fluid is sealed in the sealing portion 53. The enclosing portion 53 includes a first portion 53a provided in the trunk portion 51 and a plurality of second portions 53b provided in the plurality of branch portions 52.

  By providing the first portion 53a, the hydraulic fluid can move in the first direction. By providing the second portion 53b, a part of the vaporized hydraulic fluid can stay at the upper end of the second portion 53b.

  FIG. 4 is a sectional view taken along the line IV-IV shown in FIG. As shown in FIG. 4, the heat pipe 50 has a protruding portion 54 protruding in the second direction. The protrusion 54 projects toward the battery module 10.

  The protrusion 54 is provided on each of the plurality of branches 52. The protruding portion 54 is provided in a wide range from the lower end side to the upper end side of the branch portion 52. The top surface of the protrusion 54 is formed substantially flat. By providing the protruding portion 54 in this manner, the branch portion 52 can be brought into contact with the side surface 10b of the battery module 10 in a wide range. It is preferable that the plurality of branch portions 52 contact the side surfaces of the plurality of battery cells 20 in one-to-one correspondence.

  The second portion 53b of the enclosing portion 53 provided in the branch portion 52 is provided along the surface of the branch portion 52 facing the side surface 10b of the battery module 10. The second portion 53b is provided so as to project corresponding to the projecting portion 54.

  The coolant passage 40 contacts the branch 52 at a position higher than the position of the branch 52 in a portion that contacts the side surface of the battery module 10. The coolant channel 40 contacts the other end (upper end) of the heat pipe 50 in the third direction. The coolant channel 40 presses the plurality of branch portions 52 toward the side surface 10 b of the battery module 10.

  Here, since each of the plurality of branch portions 52 is separated from each other in the first direction, the degree of freedom of deformation is high. Therefore, by pressing the plurality of branch portions 52 against the side surface 10b of the battery module 10 as described above, each of the plurality of branch portions 52 can be easily brought into contact with the side surface 10b of the battery module 10. As described above, by providing the protruding portion 54, the branch portion 52 can be more reliably brought into contact with the side surface 10b of the battery module 10.

  Thereby, the plurality of branch portions 52 can reliably remove heat from the battery module 10. The heat from the battery module 10 is transferred to the working fluid located inside the branch 52. At this time, the working fluid takes heat and evaporates. The vaporized hydraulic fluid stays at the upper end of the second portion 53b. Since the refrigerant flow path 40 is in contact with the upper end side of the branch portion 52, the vaporized hydraulic fluid is cooled and liquefied. By such a cycle, the battery module 10 can be repeatedly cooled.

  As described above, by bringing each of the plurality of branch portions 52 into contact with the side surface 10b of the battery module 10, the battery module 10 can be reliably cooled, and the cooling performance can be improved.

  Further, since the refrigerant flow path 40 is provided so as to extend along the first direction, the refrigerant flow path length is shorter than when the refrigerant flow path 40 is meandering or formed in a ladder shape. The increase can be suppressed. As described above, by suppressing the increase in the refrigerant flow path length and cooling the working fluid in the heat pipe 50 by the refrigerant flow path 40, it is possible to suppress an increase in the refrigerant amount of the cooling system.

  In the above-described embodiment, the case where the heat pipe 50 is pressed toward the side surface 10b of the battery module 10 by the coolant channel 40 has been described as an example, but the present invention is not limited to this. An elastic member is provided between the side surface of the battery module 10 and the side surface of the case 11 opposed thereto, and the heat pipe 50 may be pressed toward the side surface 10b of the battery module 10 by the elastic member. .

  In the above-described embodiment, the case has been described in which the protrusions 54 are provided on the plurality of branch portions 52 and the protrusions 54 contact the side surface 10 b of the battery module 10. However, the present invention is not limited thereto. . As long as the plurality of branches 52 can be brought into contact with the side surface 10b of the battery module 10, the protrusion 54 may be omitted and the plurality of branches 52 may be formed flat.

  In the above-described embodiment, no wick is provided on the inner wall of the heat pipe 50 that defines the enclosing portion 53, and the refrigerant flow passage 40 is located at a position closer to the branch portion 52 that contacts the side surface of the battery module 10. However, the present invention is not limited to this case. A wick may be provided on the inner wall of the heat pipe 50, and the movement of the hydraulic fluid may be guided by the wick. In this case, the coolant flow path 40 does not need to contact the branch 52 at a position higher than the position of the branch 52 at the portion contacting the side surface of the battery module 10. When providing a wick, the heat pipe 50 may be brought into contact with the bottom surface of the battery module 10. When no wick is provided on the inner wall of the heat pipe 50, the configuration of the heat pipe 50 can be simplified.

  In the above-described embodiment, the case where power storage device 1 is a battery has been described as an example, but a capacitor module (power storage module) including a plurality of unit capacitors (unit power storage units) arranged in one direction other than the battery. May be provided.

  As described above, the embodiments disclosed this time are illustrative in all aspects and are not restrictive. The scope of the present invention is defined by the appended claims, and includes all modifications within the scope and meaning equivalent to the claims.

  REFERENCE SIGNS LIST 1 power storage device, 2 vehicle, 5, 6 rotating electric machine, 10 battery module, 10 a end face, 10 b side face, 10 c main face, 11 case, 20 battery cell, 21 restraint, 25, 26 end plate, 27 restraint band, 30 cooling Mechanism, 40 refrigerant flow path, 50 heat pipe, 51 trunk, 52 branch, 53 enclosing part, 53a first part, 53b second part, 54 projecting part.

Claims (1)

A power storage module including a plurality of power storage cells arranged in a first direction and having a pair of surfaces facing each other in a second direction orthogonal to the first direction;
A cooling mechanism for cooling at least one of the pair of surfaces,
The cooling mechanism includes a refrigerant flow path provided to extend along the first direction, and a heat pipe in contact with at least one of the pair of surfaces,
The heat pipe includes a trunk extending continuously along the first direction, and a plurality of branches branching from the trunk and extending along a third direction orthogonal to the first direction and the second direction. Has a comb shape,
The power storage device, wherein the plurality of branch portions abut on at least one of the pair of surfaces and abut on the refrigerant flow path.

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