Battery Cooling System

Abstract

To provide a battery cooling system capable of preventing dielectric breakdown of a cooling pipe even when connecting a cooler and the cooling pipe.SOLUTION: A battery cooling system includes a cooler 42 that is formed using a conductive member that can be electrically connected to a battery module and that has a flow path in which a coolant circulates, a cooling pipe 5 that supplies coolant to the cooler 42, a connector portion 51 that is formed using an insulating member and connects the cooling pipe 5 and the cooler 42, and a ground wire 52 electrically connected to the position of the cooling pipe 5 separated by a predetermined distance D1 from the connection point where the connector portion 51 is connected to the cooler 42.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a cooling device for a battery. [Background technology]

[0002] Patent Document 1 describes a technology for preventing dielectric breakdown caused by charging an insulating part of a resin diaphragm valve or the like used in an adjustment valve or control valve, etc., due to friction between the walls of the flow path when a liquid flows through the flow path. In this technology, a conductive member is disposed near the abdomen of the diaphragm, penetrating the flow path side of the liquid flow path, so that it comes into contact with the liquid, and is electrically connected to the ground via the body in which the conductive member and the flow path are formed, thereby preventing the insulating part of the diaphragm, etc., from being charged. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-78019 A Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, in order to miniaturize lithium-ion batteries, a structure has been considered in which a cooler that cools the lithium-ion battery also functions as a current collector. In this structure in which the cooler also functions as a current collector, a part of the cooler through which the cooling liquid flows becomes a high-voltage part, and in order to ensure safety, it is necessary to isolate the cooler from the cooling pipe that functions as an insulating part other than the high-voltage part via an insulating member.

[0005] However, even with the technology of Patent Document 1 described above that suppresses the accumulation of electric charge on insulating members, friction when the coolant flows through the cooling piping can cause the cooling piping to be charged with electricity, which can locally exceed the withstand voltage and cause insulation breakdown in the cooling piping. Furthermore, if the cooling piping is in contact with a high-voltage part, it can cause a short circuit via the earth.

[0006] The present disclosure has been made in consideration of the above, and aims to provide a battery cooling device that can prevent insulation breakdown of the cooling piping even when a cooler and the cooling piping are connected. [Means for solving the problem]

[0007] The battery cooling device of the present disclosure is a cooling device for a battery having a battery module in which a plurality of battery cells are stacked, and includes a cooler formed using a conductive material that is electrically conductive with the battery module and has a flow path inside through which a refrigerant circulates, a cooling pipe that supplies the refrigerant to the cooler, a connector portion formed using an insulating material and connecting the cooling pipe and the cooler, and an earth wire electrically connected to a position on the cooling pipe a predetermined distance away from a connection point where the connector portion connects to the cooler. Effect of the Invention

[0008] According to the present disclosure, the cooler and the cooling piping are connected via the connector portion, and an earth wire is provided that is electrically connected to a position on the cooling piping a predetermined distance away from the connection point where the connector portion connects to the cooler, thereby achieving the effect of preventing insulation breakdown of the cooling piping even when the cooler and the cooling piping are connected. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing a schematic configuration of a vehicle on which a battery according to a first embodiment is mounted. [Diagram 2] FIG. 2 is a perspective view showing a schematic configuration of the battery. [Diagram 3] FIG. 3 is a side view of the cooling pipes and the main parts of the cooler as viewed from the arrow A in FIG. [Figure 4] FIG. 4 is a side view of a main part of the cooling pipe and the cooler according to the second embodiment. [Diagram 5] FIG. 5 is a side view of a main part of the cooling pipe and the cooler according to the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, a battery cooling device according to an embodiment of the present disclosure will be described with reference to the drawings. Note that the present disclosure is not limited to the following embodiment. In the following, the same parts are denoted by the same reference numerals.

[0011] (Embodiment 1) [General configuration of the vehicle] Fig. 1 is a schematic diagram showing a general configuration of a vehicle equipped with a battery according to embodiment 1. The vehicle 1 shown in Fig. 1 is assumed to be an electric vehicle (EV) or a plug-in hybrid vehicle (PHV) using a motor or the like as a power source.

[0012] The vehicle 1 includes a motor 2, a power control unit 3 (hereinafter referred to as “PCU 3”), a battery 4, a cooling pipe 5, an electric pump 6, a heat exchanger 7, and an ECU (Electronic Control Unit) 8.

[0013] The motor 2 outputs power for running using the power of the battery 4. The motor 2 is electrically connected to the battery 4 via the PCU 3. In the vehicle 1, the power output from the motor 2 is transmitted to the drive wheels via a power transmission device.

[0014] The PCU 3 drives and controls the motor 2. The PCU 3 includes at least an inverter that drives the motor 2, a boost converter, and a DC / DC converter. For example, the PCU 3 has an inverter that converts DC power from the battery 4 into AC power and supplies the AC power to the motor 2.

[0015] The battery 4 stores electric power to be supplied to the motor 2. Specifically, the battery 4 is an electricity storage device capable of charging electric power supplied from an external power source. The battery 4 is electrically connected to a charging plug of an external charging facility via a charging port (not shown) provided on the vehicle 1, and is charged with electric power supplied from the charging facility. The battery 4 is configured using a battery module in which multiple planar cells are stacked vertically, and a cooler that cools the battery module. The detailed configuration of the battery 4 will be described later.

[0016] The cooling pipe 5 has a flow path connected to the battery 4, an electric pump 6, and a heat exchanger 7, and a refrigerant that cools the battery 4 circulates through it. The refrigerant may be any of air, water, mineral oil, synthetic oil, silicone oil, fluorine oil, insulating refrigerant (e.g., an alternative fluorocarbon refrigerant such as R134a), and insulating oil. In the first embodiment, a case where water is used as the refrigerant will be described. The cooling pipe 5 is made of a non-conductive material or the like. Specifically, the cooling pipe 5 is made of rubber, resin, or the like.

[0017] The electric pump 6 circulates the refrigerant in the cooling pipe 5 under the control of the ECU 8. Specifically, the electric pump 6 draws in the refrigerant stored in the reserve tank and discharges the refrigerant from a discharge port toward the cooling pipe 5. The refrigerant discharged by the electric pump 6 circulates through the cooling pipe 5, the battery 4, and the heat exchanger 7 by the discharge pressure of the electric pump 6.

[0018] Under the control of the ECU 8, the heat exchanger 7 exchanges heat with the refrigerant circulating inside the cooling pipe 5 to dissipate heat from the refrigerant. The heat exchanger 7 is configured using, for example, a radiator, an electric fan, and the like.

[0019] The ECU 8 controls the operation of the electric pump 6 and the heat exchanger 7. The ECU 8 is configured using a processor having hardware such as a memory and a CPU (Central Processing Unit).

[0020] [Detailed battery configuration] Next, a detailed configuration of the battery 4 will be described. Fig. 2 is a perspective view showing a schematic configuration of the battery.

[0021] As shown in FIG. 2, the battery 4 includes a battery module 41 in which a plurality of battery cells 410 are stacked, and a flat-plate-shaped cooler 42 that is connected to both the upper and lower surfaces of the battery module 41 and cools the battery module 41. Specifically, as shown in FIG. 2, the battery 4 is configured by stacking the cooler 42, the battery module 41, and the cooler 42 in this order. Note that the battery 4 shown in FIG. 2 includes one battery module 41, but the number of stacked battery modules 41 can be changed as appropriate as long as the battery module 41 can be stacked with the upper and lower surfaces sandwiched between the coolers 42. Furthermore, the number of coolers 42 can be changed as appropriate according to the number of stacked battery modules 41 as long as the battery module 41 can be stacked with the coolers 42 sandwiched between them.

[0022] The battery module 41 is configured by stacking a plurality of flat plate-shaped battery cells 410 vertically. The battery cells 410 are configured using either a bipolar structure or a monopolar structure. Furthermore, in Fig. 2, the battery 4 is configured by stacking four layers of battery cells 410, but the number of stacked battery cells 410 can be changed as appropriate.

[0023] The cooler 42 has an inlet portion 421 connected to the cooling pipe 5 and supplied with the refrigerant Wa from the electric pump 6 through the cooling pipe 5, and an outlet portion 422 connected to the cooling pipe 5 and discharging the refrigerant Wa to the cooling pipe 5. The cooler 42 cools the battery module 41 by circulating the refrigerant Wa through a flow path formed inside. The cooler 42 is made of a conductive material, such as aluminum. Furthermore, the coolers 42 positioned above and below the battery 4 function as electrodes (current collector plates) of the battery 4 by being electrically connected to the battery module 41. This eliminates the need to provide terminals for extracting power from the battery 4, and thus allows the battery 4 to be made smaller. In the first embodiment, the cooling pipe 5, the electric pump 6, the heat exchanger 7, and the cooler 42 function as a cooling device for the battery 4.

[0024] [Connection between cooling piping and cooler] Next, a method for connecting the cooling pipe 5 and the cooler 42 will be described in detail. Fig. 3 is a side view of the main parts of the cooling pipe 5 and the cooler 42 as seen from the arrow A in Fig. 2. Note that Fig. 3 describes in detail the connection between the cooling pipe 5 and the inlet part 421 of the cooler 42, but the cooling pipe 5 and the outlet part 422 of the cooler 42 are also connected in a similar manner.

[0025] 3, the inlet portion 421 of the cooler 42 is connected to the cooling pipe 5 via the connector portion 51. The connector portion 51 is formed of an insulating material, such as rubber or resin, and has a cylindrical shape. Furthermore, the cooling pipe 5 is electrically connected to an earth wire 52, which is grounded to the earth, at a position a predetermined distance D1 away from an end portion 421a of the connection side where the connector portion 51 is connected to the inlet portion 421. The earth is electrically connected to the vehicle 1.

[0026] Here, the predetermined distance D1 is a position from the connection side of the connector part 51 (the end part 421a side of the inlet part 421) to 5.6 mm toward the cooling pipe 5 when the voltage of the battery 4 is 400V, the minimum spatial distance is 0.8 mm, and the minimum creepage distance is 5.6 mm in an environment of pollution degree 3 according to JIS C0664. That is, the earth wire 52 is electrically connected to a position where the total distance between the connector part 51 and the cooling pipe 5 is 5.6 mm or more away from the cooler 42 (inlet part 421) functioning as a high-pressure part.

[0027] This allows the battery 4 to cut off the electrical continuity between the battery module 41 and the cooler 42, and even if the cooling piping 5 becomes charged, the cooling piping 5, which functions as an insulating part, can be prevented from suffering an electrical breakdown.

[0028] In the embodiment 1 described above, the cooling pipe 5 and the cooler 42 are connected via the connector portion 51, and an earth wire 52 is provided that is electrically connected to a position on the cooling pipe 5 a predetermined distance away from the connection point where the connector portion 51 is connected to the cooler 42, thereby making it possible to prevent insulation breakdown of the cooling pipe 5.

[0029] In addition, in embodiment 1, the connector portion 51 is provided between the inlet portion 421 of the cooler 42 and the cooling pipe 5, but the connector portion 51 may be provided between the outlet portion 422 of the cooler 42 and the cooling pipe 5, and the earth wire 52 may be electrically connected at a position a predetermined distance away.

[0030] In addition, in the first embodiment, the cooling pipe 5 is formed of a non-conductive material, but the present invention is not limited to this. For example, the cooling pipe 5 may be formed of a conductive material, and the surface of the cooling pipe 5 and the inner wall of the flow path through which the cooling liquid flows may be subjected to an insulating treatment in which an insulating material is applied or an anodizing treatment, etc., to provide an insulating coating so that the cooling pipe 5 functions as an insulating section.

[0031] (Embodiment 2) Next, a description will be given of embodiment 2. Fig. 4 is a side view of the cooling pipe and the main part of the cooler according to embodiment 2.

[0032] As shown in FIG. 4, instead of the cooling pipe 5 and the connector portion 51 of the first embodiment, a cooling pipe 5A and a connector portion 51A are provided.

[0033] The cooling pipe 5A is made of a conductive material such as aluminum or an aluminum alloy. Furthermore, a ground wire 52 is electrically connected to the cooling pipe 5A.

[0034] The connector portion 51A has a predetermined length D2 in the flow path direction (longitudinal direction) in which the refrigerant Wa flows. Specifically, the length D2 of the connector portion 51A is 5.6 mm when the minimum clearance distance is 0.8 mm and the minimum creepage distance is 5.6 mm in an environment of pollution level 3 according to JIS C 0664. The connector portion 51A is formed of an insulating material such as rubber or resin, and has a cylindrical shape.

[0035] According to the above-described embodiment 2, by connecting the cooler 42 and the cooling pipe 5A via the connector portion 51A having a predetermined length D2, it is possible to reduce the number of places where insulation material is used, which may cause dielectric breakdown, and to increase the area of ​​connection with the connector portion 51A that functions as an insulating material. This makes it possible to better prevent dielectric breakdown from occurring in the cooling pipe 5A compared to embodiment 1.

[0036] (Embodiment 3) Next, a description will be given of embodiment 3. Fig. 5 is a side view of the main parts of the cooling pipe and the cooler according to embodiment 3.

[0037] As shown in FIG. 5, in addition to the configuration of the first embodiment, the cooling pipe 5 is electrically connected with SW1, capacitors C1, SW2, and a power fuse R1.

[0038] The cooling pipe 5 is electrically connected to the ground via SW1 and capacitor C1. The capacitance of capacitor C1 is set so that insulation breakdown due to charging does not occur. Furthermore, in the cooling pipe 5, a power fuse R1 (resistor) is electrically connected to the ground via switch SW2 in parallel with capacitor C1. The power fuse R1 is set so that it does not break when the charge of capacitor C1 is discharged and only breaks when a short circuit occurs. SW1 and SW2 perform on / off operations under the control of ECU 8. As a result, the charge stored in capacitor C1 is periodically discharged via power fuse R1.

[0039] According to the above-described embodiment 3, by electrically connecting an earth to the cooling pipe 5 via at least one of the capacitor C1 and the power fuse R1, it is possible to prevent dielectric breakdown in the cooling pipe 5 even if the position of the earth does not allow the necessary distance for insulation from the cooler 42 functioning as a high-voltage part to be secured.

[0040] Furthermore, according to the third embodiment, the ECU 8 electrically disconnects the capacitor C1 from the cooling pipe 5 via the switch SW1 when the capacitor C1 is discharging, so that the charge stored in the cooler 42 can be periodically discharged.

[0041] (Other embodiments) Further advantages and modifications may readily occur to those skilled in the art. The invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Thus, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and equivalents thereof. [Explanation of symbols]

[0042] 1 vehicle 2 Motors 3 PCU 4 batteries 5,5A cooling pipe 6. Electric Pump 7 Heat exchanger 8 ECU 41 Battery Module 42 Cooler 51,51A Connector part 52 Earth wire 410 Battery Cell 421 Inlet 421a End 422 Outlet Section C1 Capacitor R1 Power fuse SW1, SW2 switches Wa refrigerant

Claims

[Claim 1] A cooling device for a battery having a battery module in which a plurality of battery cells are stacked, a cooler formed of a conductive member capable of conducting with the battery module and having a flow path therein through which a refrigerant circulates; A cooling pipe for supplying the refrigerant to the cooler; a connector portion formed using an insulating material and connecting the cooling pipe and the cooler; a ground wire electrically connected to the cooling pipe at a position separated by a predetermined distance from a connection point where the connector portion is connected to the cooler; Equipped with Battery cooling device.

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