JP2014137930A - Battery system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery system using a plurality of battery cells, which can contribute to uniform cooling effect, and can contribute to long life by suppressing the aging of the battery cells.SOLUTION: A battery system includes a battery module 20 configured by arranging a plurality of battery cells 10, an evaporation section 3 which is arranged in contact with the battery cells 10 while having a refrigerant passage 2 for internally circulating the refrigerant, and which evaporates the liquid-phase refrigerant flowing therein, a compressor 4 for compressing the refrigerant flowing out of the evaporation section 3, a condenser 5 for condensing the refrigerant compressed by the compressor 4, and an expansion valve 6 for supplying the refrigerant condensed by the condenser 5 to the evaporation section 3 while expanding.

Description

  The present invention relates to a battery system.

  Conventionally, a battery group having a plurality of secondary batteries and a case containing the battery group are provided, and each secondary battery of the battery group is cooled by flowing cooling air around the battery group to A battery system configured to suppress a temperature rise is known (see, for example, Patent Document 1).

JP 2010-192209 A

  However, in the battery system described above, if the current during storage and discharge of the secondary battery is increased, the amount of heat generated by the secondary battery also increases. There was a risk of running out. At this time, the secondary battery located on the downstream side with respect to the flow of the cooling air is arranged on the upstream side in order to cool the secondary battery located on the upstream side with air whose temperature has increased after cooling. The secondary battery and the secondary battery disposed on the downstream side have biased the cooling effect, causing problems such as the early deterioration of the secondary battery disposed on the downstream side. .

  Therefore, the present invention provides a battery system that can contribute to uniform cooling effect in a battery system using a plurality of battery cells, and can contribute to a long life by suppressing deterioration of the battery cells over time. The purpose is to provide.

In order to solve the above problems, the present invention proposes the following means.
The battery system of the present invention has a battery module configured by arranging a plurality of battery cells, a refrigerant flow path that is arranged so as to be in contact with the battery cells of the battery module, and through which the refrigerant flows, An evaporator that evaporates the refrigerant in the liquid phase, a compressor that compresses the refrigerant flowing out of the evaporator, a condenser that condenses the refrigerant compressed by the compressor, and the refrigerant condensed by the condenser is expanded And an expansion valve that supplies the evaporating section.

  According to this configuration, a gaseous refrigerant is compressed by a compressor, cooled by a condenser to produce a liquid having a high pressure, the pressure is reduced by an expansion valve, and vaporized at a low temperature by an evaporation unit, and the heat of vaporization and By exchanging heat in the evaporator, the refrigerant during the evaporation process in the evaporation section becomes isothermal, so that it can contribute to the uniform cooling effect of the battery cell without lowering the cooling performance, and the deterioration of the battery cell over time. It can be suppressed and contribute to longer life.

  In the battery system of the present invention, the volatile insulating fluid is used as the refrigerant, thereby preventing environmental pollution.

  In the battery system of the present invention, a heat exchanger is disposed between the refrigerant flowing from the evaporator to the compressor and the refrigerant flowing from the condenser to the expansion valve, and the evaporator Then, the refrigerant is heated in the range from the liquid phase to the two-phase flow, and the heat exchanger is characterized in that the two-phase flow refrigerant flowing from the evaporation section is heated to the gas phase.

  According to this configuration, it is possible to construct a large battery system in which a large number of battery modules are arranged.

  In the battery system of the present invention, the evaporating part includes a main body part in which a plurality of the refrigerant flow paths are formed, and an inflow part and an outflow part of a refrigerant that are provided integrally with the main body part and communicate with the refrigerant flow path. It is characterized by providing these.

  According to this configuration, a simple and inexpensive evaporation unit can be configured.

  Moreover, in the battery system of the present invention, the evaporation section is disposed between the adjacent battery cells among the plurality of battery cells, and is disposed in close contact with both opposing wall surfaces. It is characterized by.

  According to this configuration, since the battery cell is in close contact with the evaporation unit, the battery cell can be efficiently cooled.

  According to the battery system of the present invention, in a battery system using a plurality of secondary batteries, it is possible to contribute to the uniform cooling effect, and to contribute to a long life by suppressing deterioration over time of the secondary battery. Can do.

It is a block diagram of the battery system which concerns on one Embodiment of this invention. It is the perspective view which fractured | ruptured a part of battery cell applied to the battery system which concerns on one Embodiment of this invention. It is a top view of the battery module applied to the battery system which concerns on one Embodiment of this invention. An example of the evaporation part applied to the battery system which concerns on one Embodiment of this invention is shown, (A) is a side view of an evaporation part, (B) is sectional drawing which follows the BB line of (A). It is a graph of the cooling cycle in the battery system which concerns on one Embodiment of this invention. It is a block diagram of the battery system of the modification which concerns on one Embodiment of this invention. It is a graph of the cooling cycle in the battery system of the modification which concerns on one Embodiment of this invention. It is explanatory drawing of the battery system of the modification which concerns on one Embodiment of this invention. It is explanatory drawing of the example of arrangement | positioning of the evaporation part in the battery system of the modification which concerns on one Embodiment of this invention.

Next, a battery system according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram of a battery system according to an embodiment of the present invention.

  As shown in FIG. 1, the battery system 1 of the present invention is configured to contact a battery cell 10 with a battery module 20 in which a plurality of secondary batteries (hereinafter referred to as “battery cells”) 10 are arranged. An evaporator 3 for evaporating inflowing liquid phase refrigerant, a compressor 4 for compressing refrigerant flowing out of the evaporator 3, and a compressor 4 A condenser 5 for condensing the refrigerant compressed in step (b), and an expansion valve 6 for expanding the refrigerant condensed in the condenser 5 and supplying the refrigerant to the evaporator 3.

  In addition, as a refrigerant | coolant used with the battery system 1, VDF (Vaporable Dielectric Fluid: Volatile insulating fluid) is used, and the alternative CFC type refrigerant | coolant (for example, R134a) is specifically used.

[Configuration of Battery Cell 10]
FIG. 2 is a perspective view in which a part of the battery cell 10 is broken. As shown in FIG. 2, the battery cell 10 is provided with the battery container 11 which stores electrolyte solution inside. The battery cell 10 is, for example, a lithium ion secondary battery. The battery container 11 is an aluminum hollow container, for example. The battery container 11 of this example has a substantially prismatic shape (substantially rectangular parallelepiped shape). The battery container 11 includes a cylindrical body 11a having an opening and a lid 11b that closes the opening of the cylindrical body 11a.

  The lid 11b is provided with electrode terminals 12 and 13 and an electrolyte inlet 14. For example, the electrode terminal 12 is a positive terminal and the electrode terminal 13 is a negative terminal. Electrodes 15 and 16 and a separator 17 are accommodated inside the battery container 11.

  The electrodes 15 and 16 are formed by using a sheet-like current collector (conductor) such as a conductor foil or a conductor thin plate as a base material, and coating the surface of the base material with an electrode active material corresponding to the type of the electrolytic solution. . The electrode 15 is, for example, a positive electrode plate, and a positive electrode active material layer containing an electrode active material (positive electrode active material) made of lithium-containing iron fluoride is formed on the surface of an aluminum base material. The electrode 16 is, for example, a negative electrode plate, and a portion in contact with the electrolytic solution is made of graphite.

  The electrode 15 is disposed to face the electrode 16. The electrodes 15 and 16 are repeatedly arranged in directions facing each other. A separator 17 is provided between the electrodes 15 and 16 so that the electrodes 15 and 16 do not contact each other. The separator 17 is made of an insulating material such as a porous resin film. In FIG. 2, for convenience of explanation, the thickness of the separator 17 is shown to be thinner than the thickness of the electrodes 15, 16, but this does not indicate the actual thickness relationship.

  An electrode tab 15a is formed at the end of the electrode 15 on the electrode terminal 12 side. The electrode tabs 15 a of the plurality of electrodes 15 that are repeatedly arranged are collectively connected to the electrode terminal 12. An electrode tab 16a is formed at the end of the electrode 16 on the electrode terminal 13 side. The electrode tabs 16 a of the plurality of electrodes 16 that are repeatedly arranged are collectively connected to the electrode terminal 13.

  In the battery container 11, the electrolytic solution is stored so as to come into contact with the electrodes 15 and 16. As an electrolyte for a lithium ion secondary battery, for example, a lithium salt such as lithium hexafluorophosphate or lithium tetrafluoroborate is dissolved in an organic solvent such as ethylene carbonate, diethyl carbonate, methyl ethyl carbonate, or propylene carbonate. And the like. Further, when the battery cell 10 is a sodium secondary battery, examples of the electrolyte solution for the sodium secondary battery include a solution in which a sodium salt such as sodium perchlorate is dissolved in an organic solvent.

[Configuration of Battery Module 20]
FIG. 3 is a plan view of the battery module 20. In addition, in this FIG. 3, it demonstrates by the case where the two adjacent battery cells 10 (a pair) are arranged in 4 sets (4 rows). In the following description, this arrangement state is referred to as one battery cell unit.

  As shown in FIG. 3, the battery module 20 includes a pair of restraining plates 21 and 21 located on both side surfaces of one battery cell unit, and a shaft member that holds one battery cell unit by the pair of restraining plates 21 and 21. 22 and 22.

  The pair of restraining plates 21 and 21 is a metal plate (for example, aluminum) having high heat resistance and a certain degree of rigidity. The shaft members 22, 22 are configured as cylinders or prismatic bodies from the same or different metals as the restraining plates 21, 21. The shaft members 22 and 22 have female screw holes formed at both end faces thereof, and are fixed near the four corners of the restraining plates 21 and 21 by bolts or the like. The shaft members 22 and 22 define the facing distance between the pair of restraining plates 21 and 21 according to their lengths. Therefore, the length of the shaft members 22 and 22 is determined by one battery cell unit held by the pair of restraining plates 21 and 21.

[Configuration of Evaporating Unit 3]
FIG. 4 shows an example of the evaporation unit 3, FIG. 4 (A) is a side view of the evaporation unit 3 in a state where the battery cells 10 are arranged, and FIG. 4 (B) is a line BB in FIG. 4 (A). It is sectional drawing which follows. As shown in FIG. 3, the evaporating unit 3 is disposed in close contact between each row of the pair of battery cells 10. In FIG. 3, the evaporation unit 3 is not disposed between the restraining plate 21 and the battery cell 10, but can be disposed in close contact with the restraining plate 21 and the battery cell 10. .

  The evaporation unit 3 as a heat exchange function evaporates and vaporizes the refrigerant. As shown in FIG. 4A, the evaporation unit 3 includes a rectangular (rectangular) main body 3a in a side view, and an inflow portion 3b and an outflow portion 3c that are oppositely triangle-shaped on two opposite sides of the main body 3a. And are integrally provided. As shown in FIG. 4B, a plurality of refrigerant flow paths 2 are formed in the evaporation unit 3. The refrigerant flow path 2 communicates with the inflow portion 3b and the outflow portion 3c, and is configured such that the refrigerant passes from the inflow portion 3b to the outflow portion 3c via the inside of the main body portion 3a. In addition, the evaporation part 3 can be comprised with a one-piece | unit or a half-matching structure body by aluminum die-casting etc., and can be set as the simple and cheap evaporation part 3.

  Since the compressor 4, the condenser 5, and the expansion valve 6 are well-known ones, a detailed description thereof is omitted here, but the following functions are provided. The compressor 4 compresses the gaseous refrigerant to a high temperature and a high pressure. The condenser 5 as a heat exchange function liquefies the refrigerant with air (see the white arrow in FIG. 1). The expansion valve 6 has a function of reducing the pressure of the liquid refrigerant to reduce the pressure and adjusting the circulation amount of the refrigerant.

  In the above-described configuration, in the battery system 1 of the present invention, as shown in FIG. It constitutes a compression cooling cycle. Note that the circled numbers shown in FIG. 5 correspond to the path of the circled numbers in FIG.

  Specifically, the refrigerant that has become liquid when condensed in the condenser 5 is heat-exchanged to form a cooling gas. When the gas passes through the expansion valve 6 and then passes through the refrigerant flow path 2 of the evaporation unit 3, the gas cools the battery cell 10 by heat exchange (heats the refrigerant in the evaporation unit 3). Evaporates by heat exchange. At this time, since the evaporating unit 3 is in close contact with the battery cell 10, the cooling efficiency can be ensured. Furthermore, the refrigerant that has become high temperature when passing through the refrigerant flow path 2 of the evaporation section 3 exchanges heat with the refrigerant that is condensed again by the condenser 5 and becomes liquid.

  In the present embodiment, gaseous refrigerant is compressed by the compressor 4, cooled by the condenser 5 to produce a high-pressure liquid, the pressure is reduced by the expansion valve 6, and vaporized at a low temperature by the evaporation unit 3. Heat exchange is performed with the battery cell 10 by heat. Thereby, since the refrigerant during the evaporation process by the evaporation unit 3 becomes isothermal, it can contribute to the uniform cooling effect of the battery cell 10 without deteriorating the cooling performance, and the deterioration of the battery cell 10 over time. It can be suppressed and contribute to longer life. Moreover, it is possible to perform cooling using latent heat during the evaporation process, and the cooling performance can be maintained high.

  Moreover, since the required flow rate of the refrigerant can be kept low, it is possible to contribute to miniaturization and power saving of the gas liquefaction heat pump (or the expansion valve 6) and the power supply (both not shown) for circulating the refrigerant. .

  Furthermore, even if the cooling medium leaks in the middle of the circulation path, the power source and the like can be arranged separately, so that the risk of electric leakage can be avoided. In addition, due to the simple circulation path, the design of the refrigerant flow path 2 according to the capacity of the battery cell 10 and the like, and the use of volatile insulating fluid (VDF) as the refrigerant, etc. The refrigerant can be prevented from freezing. Thereby, for example, maintenance of each part such as sterilization treatment and filter replacement can be unnecessary and reduced.

[Modification]
By the way, in the said embodiment, although the condenser 5 was used as a heat exchanger after cooling the battery cell 10, as shown in FIG.6 and FIG.7, it flows in into the compressor 4 from the evaporation part 3, for example. The heat exchanger 7 is arranged between the refrigerant that flows into the expansion valve 6 from the condenser 5, and the two-phase flow refrigerant that flows in from the evaporator 3 is vaporized by the heat exchanger 7. You may make it heat to. As a cooling path in this case, vapor compression cooling with a gas-liquid two-phase refrigerant in the path of the evaporator 3, the heat exchanger 7, the compressor 4, the condenser 5, the heat exchanger 7, the expansion valve 6, and the evaporator 3. It becomes a cycle.

  Moreover, by using such a heat exchanger 7, as shown in FIG. 8, it is possible to construct a large battery system 1 in which a large number of battery modules 20 are arranged. The battery system 1 shown in FIG. 8 includes a casing 8 in which 23 battery modules 20 are arranged in a shelf manner as indicated by numbers in parentheses in the figure, and a compressor 4, a condenser 5, an expansion are provided in the lower stage thereof. A valve 6 and a heat exchanger 7 are arranged. Note that the gas liquefied heat pump and the power source (or the electric control device 9) described above can be arranged in the lower stage of the housing 8. In FIG. 8, a thick black arrow indicates a cooling path for each battery module 20, and the upstream outflow portion 3c and the downstream inflow portion 3b are connected by a refrigerant pipe or the like.

  At this time, for example, as shown in FIG. 9, if the evaporator 3 in the former battery module 20 and the evaporator 3 in the latter battery module 20 are disposed in opposite directions, the same evaporator 3 is used. In addition, the piping route of the refrigerant piping can be shortened and simplified, and the deterioration of the cooling efficiency can be suppressed.

  In the above-described embodiment (including the modification), the battery module 20 is illustrated in which the battery cells 10 are arranged in a pair of four rows, but the number and the number of the battery cells 10 in one row are particularly limited. However, it is optional depending on the desired overall output of the battery system 1 and the like.

  Further, the number of battery modules 20 shown in the modification, the shelf arrangement, and the entire cooling path are arbitrary. For example, after the battery module 20 is cooled from the lower stage to the upper stage, the upper stage to the lower stage of the adjacent stage is cooled, and the like can be changed according to the number of battery modules 20 and the shelf arrangement.

DESCRIPTION OF SYMBOLS 1 ... Battery system 2 ... Refrigerant flow path 3 ... Evaporating part 4 ... Compressor 5 ... Condenser 6 ... Expansion valve 7 ... Heat exchanger 10 ... Battery cell (secondary battery)
20 ... Battery module

Claims (5)

A battery module configured by arranging a plurality of battery cells;
An evaporation section that is arranged so as to be in contact with the battery cells of the battery module, has a refrigerant flow path through which the refrigerant flows, and evaporates the flowing liquid-phase refrigerant;
A compressor that compresses the refrigerant flowing out of the evaporation section;
A condenser that condenses the refrigerant compressed by the compressor;
An expansion valve for expanding the refrigerant condensed in the condenser and supplying the refrigerant to the evaporation unit;
A battery system comprising: The battery system according to claim 1,
The battery system is characterized in that a volatile insulating fluid is used for the refrigerant. The battery system according to claim 1 or 2,
A heat exchanger is disposed between the refrigerant flowing from the evaporator to the compressor and the refrigerant flowing from the condenser to the expansion valve;
In the evaporation section, the refrigerant is heated in a range from a liquid phase to a two-phase flow,
In the heat exchanger, the two-phase refrigerant flowing from the evaporation section is heated to a gas phase. The battery system according to any one of claims 1 to 3,
The evaporation section is
A main body formed with a plurality of the refrigerant flow paths;
An inflow portion and an outflow portion of a refrigerant provided integrally with the main body portion and communicating with the refrigerant flow path;
A battery system comprising: The battery system according to any one of claims 1 to 4,
The evaporation section is
Among the plurality of battery cells, the battery system is disposed between the adjacent battery cells and is in close contact with both opposing wall surfaces.

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