Battery pack

Abstract

The invention relates to a battery pack which comprises a battery module, a first heat dissipation device and a second heat dissipation device, the battery module comprises a plurality of battery cells, one end of each battery cell is provided with a pole, the first heat dissipation device is arranged on the battery module, and the end, provided with the pole, of each battery cell is located in the first heat dissipation device; the second heat dissipation device is arranged on the side, away from the battery module, of the first heat dissipation device. The first heat dissipation device comprises a first cavity, immersion liquid is arranged in the first cavity, and the end, provided with the pole, of the battery cell is located in the immersion liquid. The second heat dissipation device comprises a second cavity, a first valve body and a second valve body, when the first valve body and the second valve body are opened, the immersion liquid can enter the second cavity from the first cavity through the first valve body, and after being cooled in the second heat dissipation device, the immersion liquid enters the first cavity from the second cavity through the second valve body so as to absorb heat generated at the battery cell pole; the temperature of the battery module is reduced, the possibility of thermal runaway of the battery pack is reduced, the service life of the battery pack can be prolonged, and the charge-discharge efficiency can be improved.

Description

Technical Field

[0001] The present application relates to the field of energy storage technology, and in particular to a battery pack. Background Art

[0002] The energy storage device includes multiple battery packs, which include multiple battery modules for storing electrical energy. During the charging or discharging process of the battery pack, a high heat will be generated on one side of the pole provided in the battery module. At present, the heat dissipation effect of the battery pack is poor, which makes the temperature inside the battery pack high, thereby affecting the life and charging and discharging efficiency of the battery pack, and easily causing thermal runaway of the battery pack, resulting in damage to the battery pack. Summary of the invention

[0003] In view of this, an embodiment of the present application provides a battery pack to solve the problem of poor heat dissipation of the battery pack.

[0004] The present application relates to a battery pack, comprising: A battery module, wherein the battery module comprises a plurality of battery cells, and along the height direction of the battery pack, one end of the battery cell has a pole; A first heat dissipation device, wherein the first heat dissipation device is disposed on the battery module, and one end of the battery cell having the pole is located in the first heat dissipation device; a second heat dissipation device, the second heat dissipation device being arranged on a side of the first heat dissipation device away from the battery module; Among them, the first heat dissipation device includes a first cavity, an immersion liquid is arranged in the first cavity, the battery cell has one end of the pole located in the immersion liquid, the second heat dissipation device includes a second cavity, a first valve body and a second valve body, the second cavity is connected to the first cavity through the first valve body and the second valve body; when the first valve body and the second valve body are opened, the immersion liquid can enter the second cavity from the first cavity through the first valve body, and enter the first cavity from the second cavity through the second valve body.

[0005] In a possible embodiment, a first flow channel is disposed in the second cavity, and the first valve body and the second valve body are respectively located at two ends of the first flow channel; and a width of the first flow channel is greater than or equal to 20 mm.

[0006] In a possible embodiment, a circulation pump is provided at both the first valve body and the second valve body. The circulation pump located at the first valve body is used to transport immersion liquid into the second cavity, and the circulation pump located at the second valve body is used to transport immersion liquid into the first cavity.

[0007] In a possible embodiment, the second heat dissipation device includes a liquid inlet and a liquid outlet, and the liquid inlet and the liquid outlet are both connected to the liquid cooling unit. When the first valve body and the second valve body are closed, the first cavity and the second cavity are separated, and the liquid cooling unit passes cooling liquid into the second cavity through the liquid inlet, and the cooling liquid flows back to the liquid cooling unit through the liquid outlet.

[0008] In a possible embodiment, a second flow channel is provided in the second cavity, the liquid inlet is connected to one end of the second flow channel, and the liquid outlet is connected to the other end of the second flow channel; along the flow direction of the coolant, the cross-sectional area of ​​the second flow channel gradually decreases.

[0009] In a possible embodiment, the second flow channel has a width of 10 mm to 20 mm, and a height less than or equal to 5 mm.

[0010] In a possible embodiment, a single-layer isolation plate is disposed between the first cavity and the second cavity.

[0011] In a possible embodiment, a plurality of heat conducting members are disposed on a side of the second heat dissipation device close to the first heat dissipation device, and ends of the plurality of heat conducting members away from the second heat dissipation device are located in the first cavity.

[0012] In a possible embodiment, the heat conducting member includes a third cavity, and the third cavity is communicated with the second cavity.

[0013] In a possible embodiment, the second heat dissipation device includes a liquid inlet and a liquid outlet, and the liquid inlet and the liquid outlet are both connected to the compressor. When the first valve body and the second valve body are closed, the first cavity and the second cavity are separated, and the compressor introduces refrigerant into the second cavity through the liquid inlet, and the refrigerant is vaporized and flows back to the compressor through the liquid outlet.

[0014] The present application relates to a battery pack, including a battery module, a first heat sink and a second heat sink. The battery module includes a plurality of battery cells, one end of which has a pole. The first heat sink is arranged on the battery module, and the end of the battery cell with the pole is located in the first heat sink. The second heat sink is arranged on the side of the first heat sink away from the battery module. The first heat sink includes a first cavity, and an immersion liquid is arranged in the first cavity. The end of the battery cell with the pole is located in the immersion liquid. The second heat sink includes a second cavity, a first valve body and a second valve body. When the first valve body and the second valve body are opened, the immersion liquid can enter the second cavity from the first cavity through the first valve body, and after cooling in the second heat sink, enter the first cavity from the second cavity through the second valve body to absorb the heat generated at the pole of the battery cell, reduce the temperature of the battery module, and help reduce the possibility of thermal runaway of the battery pack, and can also improve the life and charging and discharging efficiency of the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0016] Figure 1 A schematic diagram of the structure of an embodiment of a battery module and a heat dissipation device provided in an embodiment of the present application; Figure 2 A schematic diagram of an embodiment of a second heat dissipation device provided in an embodiment of the present application; Figure 3 A schematic diagram of another embodiment of a second heat dissipation device provided in an embodiment of the present application; Figure 4 A schematic structural diagram of another embodiment of a battery module and a heat dissipation device provided in an embodiment of the present application; Figure 5 A schematic structural diagram of another embodiment of a battery module and a heat dissipation device provided in an embodiment of the present application.

[0017] Reference numerals: 1-Battery module; 11-battery cell; 111- pole; 2-first heat dissipation device; 21- first cavity; 3- second heat dissipation device; 31- second cavity; 311-first flow channel; 312-second flow channel; 32-first valve body; 33- second valve body; 34-liquid inlet; 35-liquid outlet; 4-Isolation board; 5-heat conducting parts; 51- third cavity; 6- The third heat dissipation device. DETAILED DESCRIPTION

[0018] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0019] It should be clear that the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0020] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0021] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0022] like Figure 1 and Figure 2As shown, an embodiment of the present application provides a battery pack, including a battery module 1, wherein the battery module 1 includes a plurality of battery cells 11, and the plurality of battery cells 11 are arranged side by side along the length direction of the battery pack. Along the height direction of the battery pack, one end of the battery cell 11 has a pole 111. During the charging and discharging process of the battery pack, the temperature of the battery cell 11 will rise, and the temperature change of the end of the battery cell 11 having the pole 111 will be more obvious. The battery pack also includes a first heat dissipation device 2, which is arranged on the battery module 1, and the first heat dissipation device 2 includes a first cavity 21, and an immersion liquid is arranged in the first cavity 21. The end of the battery cell 11 in the battery module 1 having the pole 111 is located in the first heat dissipation device 2 and immersed in the immersion liquid. The battery pack also includes a second heat dissipation device 3, and the second heat dissipation device 3 is arranged on the side of the first heat dissipation device 2 away from the battery module 1. The second heat dissipation device 3 includes a second cavity 31, a first valve body 32 and a second valve body 33. The second cavity 31 is connected to the first cavity 21 through the first valve body 32 and the second valve body 33. When the first valve body 32 and the second valve body 33 are opened, the immersion liquid can enter the second cavity 31 from the first cavity 21 through the first valve body 32, and enter the first cavity 21 from the second cavity 31 through the second valve body 33, so that the immersion liquid circulates in the first cavity 21 and the second cavity 31.

[0023] The immersion liquid can be a liquid of insulating material such as silicone oil to improve the safety of the battery pack, and at the same time facilitate the circulation of the immersion liquid in the first cavity and the second cavity. One end of the battery cell 11 with the pole 111 is immersed in the immersion liquid of the first cavity 21. During the charging and discharging process of the battery pack, the immersion liquid can absorb the heat generated at the pole 111 of the battery cell 11. The immersion liquid in the first cavity 21 enters the second cavity 31 through the first valve body 32, and the heat in the immersion liquid can be discharged through the second heat dissipation device 3. The cooled immersion liquid flows back to the first cavity 21 through the second valve body 33 to absorb the heat generated by the battery cell 11 and reduce the temperature of the battery pack, which is conducive to reducing the possibility of thermal runaway of the battery pack and can also improve the life and charging and discharging efficiency of the battery pack.

[0024] In a possible embodiment, a fin structure is provided on a side of the second heat dissipation device 3 away from the first heat dissipation device 2 .

[0025] The heat of the immersion liquid in the second cavity 31 will be conducted to the fin structure through the side wall of the second cavity 31. The contact area between the fin structure and the external environment is large, which can improve the heat exchange efficiency between the immersion liquid and the external environment. The fin structure on the second heat sink 3 is distributed in a matrix, and air can flow between multiple fins to take away the heat conducted to the fins. The fins are distributed in a matrix, and the width of the gap between adjacent fins is small. According to the narrow tube effect, the air flow rate between adjacent fins will increase, which can improve the heat dissipation effect of the second heat sink 3. A device that can increase the air flow rate, such as a fan, can also be provided on one side of the fin structure. When the temperature of the immersion liquid in the second heat sink 3 is high, the air flow rate between the fins can be further increased by the fan to improve the heat dissipation effect of the immersion liquid.

[0026] like Figure 1 and Figure 2 As shown, in a possible embodiment, a first flow channel 311 is provided in the second cavity 31. The first flow channel 311 may be in an S-shape, annular shape, etc. The first valve body 32 and the second valve body 33 are respectively located at both ends of the flow channel. The immersion liquid enters the flow channel from the first valve body 32, flows along the flow channel to the second valve body 33, and then flows back to the first cavity 21 through the second valve body 33.

[0027] A first flow channel 311 is provided in the second cavity 31. The immersion liquid entering the second cavity 31 needs to flow along the first flow channel 311, which can increase the residence time of the immersion liquid in the second heat dissipation device 3, thereby improving the heat dissipation effect of the second heat dissipation device 3 on the immersion liquid, so that the temperature of the immersion liquid flowing back into the first cavity 21 is lower, which can improve the heat dissipation effect on the battery cell 11.

[0028] In a possible embodiment, the width of the first flow channel 311 is greater than or equal to 20 mm.

[0029] The immersion liquid can be an insulating liquid such as silicone oil, which has a relatively high viscosity. If the width of the first flow channel 311 is less than 20 mm, the flow of the immersion liquid in the first flow channel 311 is obstructed, affecting the circulation of the immersion liquid in the first cavity 21 and the second cavity 31, resulting in a deterioration in the heat dissipation effect of the second heat dissipation device 3 on the immersion liquid, and further resulting in a deterioration in the heat dissipation effect of the first heat dissipation device 2 on the battery cell 11.

[0030] In a possible embodiment, a circulation pump is provided at both the first valve body 32 and the second valve body 33. The circulation pump located at the first valve body 32 is used to transport the immersion liquid in the first cavity 21 to the second cavity 31, and the circulation pump located at the second valve body 33 is used to transport the immersion liquid in the second cavity 31 to the first cavity 21.

[0031] The circulation pump is used to drive the immersion liquid to circulate in the first cavity 21 and the second cavity 31. By adjusting the power of the circulation pump, the flow rate of the immersion liquid circulating in the first cavity 21 and the second cavity 31 can be adjusted, thereby adjusting the heat dissipation effect of the immersion liquid on the battery cell 11. When the heat generated by the battery cell 11 is large, the power of the circulation pump can be increased to increase the speed of the immersion liquid circulating in the first cavity 21 and the second cavity 31, thereby improving the heat dissipation effect of the immersion liquid on the battery cell 11, so that the battery cell 11 is maintained at a suitable working temperature. When the heat generated by the battery cell 11 is small, the power of the circulation pump can be reduced to reduce the speed of the immersion liquid circulating in the first cavity 21 and the second cavity 31, so that the battery cell 11 is at a suitable working temperature, and the energy consumption of the circulation pump can also be reduced.

[0032] like Figure 1 and Figure 3 As shown, in a possible embodiment, when the first valve body 32 and the second valve body 33 are closed, the first cavity 21 and the second cavity 31 are separated, and the cooling liquid can be introduced into the second cavity 31 to reduce the temperature of the immersion liquid in the first cavity 21. The second heat dissipation device 3 includes a liquid inlet 34 and a liquid outlet 35, and the liquid inlet 34 and the liquid outlet 35 are both connected to the liquid cooling unit. The low-temperature cooling liquid can flow into the second cavity 31 through the liquid inlet 34, and the high-temperature cooling liquid after flowing through the second cavity 31 flows out of the second cavity 31 through the liquid outlet 35 and flows back to the liquid cooling unit. After being cooled by the liquid cooling unit, it becomes a low-temperature cooling liquid and then flows back to the second cavity 31.

[0033] The second heat dissipation device 3 is arranged on a side of the first heat dissipation device 2 away from the battery cell 11. The temperature of the immersion liquid in the first cavity 21 can be conducted to the second cavity 31 through the side walls of the first cavity 21 and the second cavity 31. A low-temperature coolant is introduced into the second cavity 31 so that the low-temperature coolant can absorb the heat conducted from the immersion liquid to the second cavity 31, thereby reducing the temperature of the immersion liquid, thereby improving the heat dissipation effect of the immersion liquid on the battery cell 11.

[0034] The immersion liquid can be an insulating material that can undergo phase change, such as paraffin. When the temperature of the battery cell 11 decreases, it can dissipate heat and solidify. When the temperature of the battery cell 11 increases, it can absorb heat and liquefy, so that the temperature of the battery cell 11 is maintained at a suitable operating temperature.

[0035] A temperature sensor is installed at the pole 111 of the battery cell 11, and the temperature sensor is electrically connected to the liquid cooling unit to conduct the detected temperature at the pole 111 to the liquid cooling unit, and the temperature of the coolant is regulated by the liquid cooling unit to adjust the heat dissipation efficiency of the second heat dissipation device 3 to the first heat dissipation device 2, and then adjust the heat dissipation efficiency of the first heat dissipation device 2 to the battery cell 11, so that the temperature of the battery cell 11 is maintained at a suitable working temperature. The suitable working temperature of the battery cell 11 is 0°C to 60°C. If the temperature of the battery cell 11 detected by the temperature sensor is within this range, the liquid cooling unit may not regulate the temperature of the coolant. If the temperature sensor detects that the temperature of the battery cell 11 is critical to or higher than the upper limit of the suitable temperature, the liquid cooling unit will lower the temperature of the coolant to improve the heat absorption effect of the coolant, improve the heat dissipation efficiency of the second heat dissipation device 3 to the first heat dissipation device 2, and then improve the heat dissipation efficiency of the first heat dissipation device 2 to the battery cell 11, so that the temperature of the battery cell 11 is maintained at a suitable working temperature. The temperature of the coolant will change with the difference between the temperature of the battery cell 11 detected by the temperature sensor and the suitable working temperature. The higher the temperature detected by the temperature sensor is above the upper limit of the suitable working temperature of the battery cell 11, the lower the temperature of the coolant entering the second cavity 31. If the temperature of the battery cell 11 detected by the temperature sensor is critical to or lower than the lower limit of the suitable temperature, the liquid cooling unit will increase the temperature of the coolant so that the coolant can heat the immersion liquid, and then heat the battery cell 11, so that the battery cell 11 is maintained at a suitable working temperature.

[0036] like Figure 3 As shown, in a possible embodiment, a second flow channel 312 is provided in the second cavity 31. The second flow channel 312 may be S-shaped or annular, etc. The liquid inlet 34 is connected to one end of the second flow channel 312, and the liquid outlet 35 is connected to the other end of the second flow channel 312. The coolant flows into the second flow channel 312 from the liquid inlet 34, flows through the second flow channel 312, and then flows out from the liquid outlet 35.

[0037] A second flow channel 312 is provided in the second cavity 31 , which increases the residence time of the coolant in the second cavity 31 , allowing the coolant to absorb more heat, thereby achieving better heat dissipation effect on the immersion liquid, and is beneficial to improving the heat dissipation effect of the immersion liquid on the battery cell 11 .

[0038] In a possible embodiment, along the flow direction of the coolant, the cross-sectional area of ​​the second flow channel 312 gradually decreases.

[0039] After entering the second flow channel 312, the low-temperature coolant absorbs the heat of the immersion liquid, causing the temperature of the coolant to rise. Along the flow direction of the coolant in the second flow channel 312, the temperature of the coolant gradually rises, and the heat absorption effect gradually decreases. Along the flow direction of the coolant, the cross-sectional area of ​​the second flow channel 312 gradually decreases, causing the flow rate of the coolant to gradually increase, thereby increasing the heat absorption capacity of the coolant, thereby improving the uniformity of the heat dissipation effect of the second heat dissipation device 3 on the immersion liquid at different positions, which is conducive to improving the heat dissipation effect of the immersion liquid on the battery cells 11 at different positions.

[0040] In a possible embodiment, the flow rate of the coolant when it passes through the liquid inlet 34 into the second flow channel 312 is greater than or equal to 5L / min. If the flow rate of the coolant when it passes through the liquid inlet into the second flow channel is less than 5L / min, the flow rate of the coolant in the second cavity 31 will be slow, and the cooling effect on the immersion liquid in the first cavity 21 will be poor, which will further affect the heat dissipation effect of the immersion liquid on the pole 111 of the battery cell 11. As the temperature detected by the temperature sensor disposed at the pole 111 increases, the flow rate of the coolant at the liquid inlet 34 gradually increases, thereby improving the cooling effect of the coolant on the immersion liquid, and further improving the cooling effect on the battery cell 11.

[0041] In a possible embodiment, the width of the second flow channel 312 is 10 mm to 20 mm.

[0042] The coolant flows in the second flow channel 312 to absorb the heat in the immersion liquid. If the width of the second flow channel 312 is less than 10 mm, it is not convenient for the coolant to flow in the second flow channel 312; if the width of the second flow channel 312 is greater than 20 mm, the coolant quickly flows through the second flow channel 312, and the time it stays in the second cavity 31 is short, and the heat dissipation effect on the immersion liquid is poor. The width of the second flow channel 312 can be 10 mm, 15 mm, 20 mm, etc., preferably 15 mm, to improve the heat dissipation effect of the coolant on the immersion liquid.

[0043] In a possible embodiment, the height of the second flow channel 312 is less than or equal to 5 mm.

[0044] The second flow channel 312 is arranged in the second cavity 31. If the height of the second flow channel 312 is greater than 5 mm, the height of the second heat sink 3 is relatively large. The second heat sink 3 is located on the side of the first heat sink 2 away from the battery cell 11, and both are located in the battery pack. The height of the second heat sink 3 is relatively large, which is easy to interfere with other components in the battery pack, causing damage to the components in the battery pack.

[0045] like Figure 1 As shown, in a possible embodiment, a single-layer isolation plate 4 is disposed between the first cavity 21 and the second cavity 31 , and the first valve body 32 and the second valve body 33 can be disposed on the isolation plate 4 .

[0046] The first heat sink 2 is installed at the end of the battery cell 11, and the second heat sink 3 is arranged on the side of the first heat sink 2 away from the battery cell 11. The isolation plate 4 can be used as the top plate of the first cavity 21 in the first heat sink 2, and can also be used as the bottom plate of the second cavity 31 in the second heat sink 3 to improve the heat conduction rate between the immersion liquid in the first cavity 21 and the cooling liquid in the second cavity 31, thereby improving the heat dissipation effect of the cooling liquid on the immersion liquid. The isolation plate 4 can be made of a material that can quickly conduct heat, such as metal, to improve the heat conduction rate between the first cavity 21 and the second cavity 31, and improve the heat dissipation effect of the immersion liquid in the first cavity 21. The isolation plate 4 can also be made of an insulating material to reduce the possibility of conduction when the pole 111 and the isolation plate 4 are accidentally touched, which is conducive to improving the safety of the battery pack. The first heat sink 2 and the second heat sink 3 can be bonded to the isolation plate 4 by UV glue, or fixed to the isolation plate 4 by other means, so that the first heat sink 2 and the second heat sink 3 maintain the IP67 sealing level to reduce the possibility of leakage of the immersion liquid or the cooling liquid.

[0047] The installation process of the first heat sink 2 and the second heat sink 3 can be as follows: first install the first heat sink 2 on the battery module 1 so that one end of the battery cell 11 in the battery module 1 provided with the pole 111 extends into the first cavity 11 of the first heat sink 1, then fix the first heat sink 2 to the battery module 1, and provide sealant at the connection between the first heat sink 2 and the battery module 1 so that the connection between the first heat sink 2 and the battery module 1 reaches the sealing level of IP67 to reduce the possibility of leakage of the immersion liquid; then inject the immersion liquid into the first cavity 21 so that the immersion liquid fills the first cavity 21 and the pole 111 is immersed in the immersion liquid; then bond the isolation plate 4 to the first heat sink 2 by UV glue so that the first cavity 21 is sealed and the immersion liquid contacts the isolation plate 4; finally bond the second heat sink 3 to the isolation plate 4 by UV glue so that the isolation plate 4 can seal the second cavity 31.

[0048] like Figure 4 As shown, in a possible embodiment, a plurality of heat conducting members 5 are disposed on one side of the second heat dissipation device 3 close to the first heat dissipation device 2. One end of the heat conducting member 5 is connected to the isolation plate 4, and the other end extends into the immersion liquid in the first cavity 21.

[0049] The heat conducting member 5 extends into the immersion liquid, increasing the contact area between the second heat sink 3 and the immersion liquid, facilitating the heat transfer from the immersion liquid to the coolant, and improving the heat dissipation effect of the coolant on the immersion liquid. Multiple heat conducting members 5 can be distributed in a matrix and evenly inserted into the immersion liquid while avoiding the poles 111 to absorb the heat of the immersion liquid at different positions, making the temperature of the immersion liquid at different positions more uniform.

[0050] like Figure 5 As shown, in a possible embodiment, the heat conducting member 5 includes a third cavity 51 , and the third cavity 51 is in communication with the second cavity 31 , so that the cooling liquid in the second cavity 31 can flow into the third cavity 51 .

[0051] One end of the heat conductor 5 extends into the immersion liquid, and the coolant can flow into the third cavity 51 in the heat conductor 5, which can increase the heat conduction area between the coolant and the immersion liquid, so that the heat in the immersion liquid can be conducted to the coolant more quickly, and then discharged through the liquid cooling unit, which can improve the cooling effect of the coolant on the immersion liquid, and then improve the heat dissipation effect on the battery cell 11.

[0052] In a possible embodiment, a liquid inlet 34 and a liquid outlet 35 are provided on the second heat dissipation device 3, and both the liquid inlet 34 and the liquid outlet 35 are connected to the compressor. When the first valve body 32 and the second valve body 33 are closed, the first cavity 21 and the second cavity 31 are separated. The compressor introduces refrigerant into the second cavity 31 through the liquid inlet 34, and the refrigerant vaporizes and absorbs heat after entering the second cavity 31, and the vaporized refrigerant flows back to the compressor through the liquid outlet 35.

[0053] The refrigerant may be freon, ammonia, carbon dioxide and a few hydrocarbons. When the refrigerant enters the second cavity 31 and vaporizes, it can absorb a large amount of heat and has a good heat dissipation effect on the immersion liquid. Therefore, when the temperature sensor arranged at the pole 111 detects that the temperature of the battery cell 11 is too high, the refrigerant can be introduced into the second cavity 31 to quickly cool the immersion liquid and reduce the possibility of thermal runaway of the battery cell 11.

[0054] In a possible embodiment, the second heat dissipation device 3 may be a fin structure, and the fin structure is disposed on the surface of the isolation plate 4 .

[0055] The fins are made of materials with good thermal conductivity, which facilitates the heat on the isolation plate 4 to be transferred to the fins, and then transferred to the external environment through the fins. The fins protrude from the isolation plate 4, and their contact area with the external environment is larger than the contact area between the isolation plate 4 and the external environment. The fins are arranged on the isolation plate 4 to improve the heat exchange efficiency between the immersion liquid and the external environment. The fins on the isolation plate 4 can be arranged in a matrix, and under the action of the narrow tube effect, the wind speed in the gap between adjacent fins can be increased. When the temperature sensor detects that the temperature of the battery cell 11 is slightly different from the appropriate operating temperature, the air flow rate on the surface of the isolation plate 4 can be increased through the fin structure, thereby improving the heat dissipation effect on the immersion liquid, so that the temperature of the immersion liquid is at a suitable operating temperature for the battery cell 11.

[0056] In a possible embodiment, the second heat dissipation device 3 may be a heat exchange tube, in which a flowing coolant flows, and the heat exchange tube may be a flat and long tube disposed on the surface of the isolation plate 4 .

[0057] The thickness of the heat exchange tube is less than or equal to 5 mm. When the heat exchange tube is arranged on the surface of the isolation plate 4, the possibility of the heat exchange tube interfering with other components in the battery pack can be reduced. Both ends of the heat exchange tube are connected to the liquid cooling unit so that the coolant can flow into the heat exchange tube. The heat in the immersion liquid is transferred to the heat exchange tube through the isolation plate 4, and then brought out by the coolant in the heat exchange tube, thereby achieving the effect of heat dissipation for the immersion liquid in the first cavity 21. The heat exchange tube can be fixed on the isolation plate 4 by a thermally conductive adhesive to accelerate the rate of heat conduction.

[0058] In a possible embodiment, a heat exchange tube is disposed in the first cavity 21 so that the heat exchange tube is located in the immersion liquid, and flowing cooling liquid flows into the heat exchange tube to absorb the heat in the immersion liquid.

[0059] The heat exchange tube is arranged in the immersion liquid and is distributed in an S shape in the immersion liquid, which can increase the contact area between the immersion liquid and the heat exchange tube, thereby increasing the rate of heat exchange between the immersion liquid and the heat exchange tube, and improving the heat dissipation effect of the heat exchange tube on the immersion liquid. The material of the heat exchange tube can be a composite material, so that the heat-conducting tube has good insulation to improve the safety of the battery pack, and also has good thermal conductivity to improve the heat exchange effect of the heat exchange tube. The heat exchange tube is located in the first cavity 21, and a coolant or refrigerant can be passed into the second cavity 31. When the temperature sensor detects that the temperature at the electrode 111 reaches a first preset temperature, the first preset temperature is higher than the suitable operating temperature of the battery cell 11, but the difference with the suitable operating temperature of the battery cell 11 is small, the coolant can be passed into the second cavity 31, and the immersion liquid in the first cavity 21 is cooled by the coolant in the second cavity 31. When the temperature sensor detects that the temperature at the electrode 111 reaches the second preset temperature, which is higher than the first preset temperature but has a small difference from the first preset temperature, a refrigerant may be introduced into the second cavity 31 to improve the cooling effect of the second heat dissipation device 3 on the immersion liquid in the first cavity 21. When the progress sensor detects that the temperature at the electrode 111 reaches the third preset temperature, which is greater than the second preset temperature, a coolant or a refrigerant is introduced into the second cavity 31, and a coolant is introduced into the heat exchange tube at the same time, so that the second heat dissipation device 3 and the heat exchange tube can absorb the heat in the immersion liquid at the same time, so as to further improve the heat dissipation effect on the immersion liquid.

[0060] In a possible embodiment, the battery pack includes a third heat dissipation device 6 , and the third heat dissipation device 6 is located at an end of the battery module 1 away from the second heat dissipation device 3 .

[0061] During the charging and discharging process of the battery pack, the end of the battery cell 11 where the pole 111 is provided will generate more heat, and the end where the pole 111 is not provided will also generate heat. A third heat sink is provided at the end of the battery cell 11 where the pole 111 is not provided to absorb the heat generated at the end of the battery cell 11 where the pole 111 is not provided. Reduce the possibility of thermal runaway of the battery cell 11. The third heat sink 6 can be a liquid cooling plate, and coolant is passed into the third heat sink 6 to absorb the heat generated at the end of the battery cell 11 where the pole 111 is not provided. The third heat exchange device 6 can also be a heat exchange tube, which is fixed to the end of the battery cell 11 where the pole 111 is not provided in a ring or S shape. When the temperature of the battery cell 11 detected by the temperature sensor is too high, a refrigerant can also be passed into the third heat sink 6 to improve the heat dissipation effect on the battery cell 11.

[0062] The present application relates to a battery pack, including a battery module 1, a first heat sink 2, and a second heat sink 3. The battery module 1 includes a plurality of battery cells 11, one end of the battery cell 11 has a pole 111, the first heat sink 2 is arranged on the battery module 1, the end of the battery cell 11 with the pole 111 is located in the first heat sink 2, and the second heat sink 3 is arranged on the side of the first heat sink 2 away from the battery module 1. The first heat sink 2 includes a first cavity 21, an immersion liquid is arranged in the first cavity 21, and the end of the battery cell 11 with the pole 111 is located in the immersion liquid. The second heat dissipation device 3 includes a second cavity 31, a first valve body 32 and a second valve body 33. When the first valve body 32 and the second valve body 33 are opened, the immersion liquid can enter the second cavity 31 from the first cavity 21 through the first valve body 32, and after being cooled in the second heat dissipation device 3, enter the first cavity 21 from the second cavity 31 through the second valve body 33 to absorb the heat generated at the pole 111 of the battery cell 11, thereby reducing the temperature of the battery module 1, which is beneficial to reducing the possibility of thermal runaway of the battery pack and can also improve the life and charging and discharging efficiency of the battery pack.

Claims

1. A battery pack, characterized in that: The battery pack comprises: A battery module (1), the battery module (1) comprising a plurality of battery cells (11), wherein along a height direction of the battery pack, one end of the battery cell (11) has a pole (111); A first heat dissipation device (2), the first heat dissipation device (2) being arranged on the battery module (1), and one end of the battery cell (11) having the pole (111) being located inside the first heat dissipation device (2); a second heat dissipation device (3), the second heat dissipation device (3) being arranged on a side of the first heat dissipation device (2) away from the battery module (1); The first heat dissipation device (2) comprises a first cavity (21), an immersion liquid is arranged in the first cavity (21), one end of the battery cell (11) having the pole (111) is located in the immersion liquid, and the second heat dissipation device (3) comprises a second cavity (31), a first valve body (32) and a second valve body (33), the second cavity (31) is connected to the first cavity (21) through the first valve body (32) and the second valve body (33); when the first valve body (32) and the second valve body (33) are opened, the immersion liquid can enter the second cavity (31) from the first cavity (21) through the first valve body (32), and enter the first cavity (21) from the second cavity (31) through the second valve body (33).

2. The battery pack according to claim 1, characterized in that: A first flow channel (311) is provided in the second cavity (31); the first valve body (32) and the second valve body (33) are respectively located at two ends of the first flow channel (311); and the width of the first flow channel (311) is greater than or equal to 20 mm.

3. The battery pack according to claim 2, characterized in that: A circulation pump is provided at both the first valve body (32) and the second valve body (33); the circulation pump located at the first valve body (32) is used to transport immersion liquid into the second cavity (31), and the circulation pump located at the second valve body (33) is used to transport immersion liquid into the first cavity (21).

4. The battery pack according to claim 1, characterized in that: The second heat dissipation device (3) comprises a liquid inlet (34) and a liquid outlet (35), wherein the liquid inlet (34) and the liquid outlet (35) are both connected to a liquid cooling unit; when the first valve body (32) and the second valve body (33) are closed, the first cavity (21) and the second cavity (31) are separated, and the liquid cooling unit introduces cooling liquid into the second cavity (31) through the liquid inlet (34), and the cooling liquid flows back to the liquid cooling unit through the liquid outlet (35).

5. The battery pack according to claim 4, characterized in that: A second flow channel (312) is provided in the second cavity (31), the liquid inlet (34) is connected to one end of the second flow channel (312), and the liquid outlet (35) is connected to the other end of the second flow channel (312); along the flow direction of the coolant, the cross-sectional area of ​​the second flow channel (312) gradually decreases.

6. The battery pack according to claim 5, characterized in that: The second flow channel (312) has a width of 10 mm to 20 mm and a height of less than or equal to 5 mm.

7. The battery pack according to claim 4, characterized in that: A single-layer isolation plate (4) is provided between the first cavity (21) and the second cavity (31).

8. The battery pack according to claim 4, characterized in that: A plurality of heat conducting members (5) are arranged on a side of the second heat dissipation device (3) close to the first heat dissipation device (2), and an end of the plurality of heat conducting members (5) away from the second heat dissipation device (3) is located in the first cavity (21).

9. The battery pack according to claim 8, characterized in that: The heat conducting member (5) comprises a third cavity (51), and the third cavity (51) is in communication with the second cavity (31).

10. The battery pack according to claim 1, characterized in that: The second heat dissipation device (3) comprises a liquid inlet (34) and a liquid outlet (35), wherein the liquid inlet (34) and the liquid outlet (35) are both connected to a compressor; when the first valve body (32) and the second valve body (33) are closed, the first cavity (21) and the second cavity (31) are separated, and the compressor introduces refrigerant into the second cavity (31) through the liquid inlet (34); the refrigerant is vaporized and flows back to the compressor through the liquid outlet (35).

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