Battery pack, liquid cooling system, vehicle and energy storage system

Abstract

The embodiment of the invention provides a battery pack, a liquid cooling system, a vehicle and an energy storage system. The battery pack comprises a box body and a plurality of battery cells, the plurality of battery cells are accommodated in the box body or the battery cells and the box body form a sealed space, each battery cell comprises a cell body and an electric connecting piece arranged on the cell body, two adjacent battery cells or the battery cells and the inner wall of the box body form a first flow channel, and the first flow channel is used for accommodating a heat exchange working medium; at least part of the core body is immersed in the heat exchange working medium, the contact area of the electric connecting piece and the heat exchange working medium is zero, and the risk that the heat exchange working medium is ionized is reduced.

Description

Technical Field

[0001] This application relates to the technical field of batteries, and particularly to a battery pack, a liquid cooling system, a vehicle, and an energy storage system. Background Art

[0002] At present, consumers pay more attention to the rapid charging ability of the battery pack. For example, when purchasing a new energy vehicle, consumers will take this as one of the main considerations. A large amount of heat is generated during the fast charging process of the battery pack. Usually, a liquid cooling plate is provided on the battery pack to regulate the temperature of the battery pack. The liquid cooling plate is connected to the battery cells of the battery pack through a thermally conductive structural adhesive. The heat transfer medium flows in the internal flow channels of the liquid cooling plate to exchange heat with the liquid cooling plate, and then the liquid cooling plate exchanges heat with the battery cells of the battery pack through the thermally conductive structural adhesive. That is, the method of regulating the temperature of the battery pack by using the liquid cooling plate is based on two heat exchange processes of the liquid cooling plate. However, there are large heat losses in the two heat exchange processes of the liquid cooling plate, which reduces the heat exchange efficiency of the liquid cooling plate. As the fast charging speed of the battery pack gradually increases, higher requirements are put forward for the heat exchange ability of the battery pack, and the existing liquid cooling method of the liquid cooling plate is difficult to meet the requirements. In addition, the battery pack may undergo thermal runaway due to factors such as collision. A large amount of heat is generated when the battery pack is in thermal runaway. The liquid cooling method of the liquid cooling plate is difficult to quickly remove the large amount of heat generated by the thermal runaway of the battery pack, and the heat accumulation affects the safety and reliability of the battery pack. Summary of the Invention

[0003] Embodiments of this application provide a battery pack, a liquid cooling system, a vehicle, and an energy storage system that are beneficial to improving the heat exchange efficiency and reducing the risk of ionization of the heat transfer medium.

[0004] In a first aspect, an embodiment of this application provides a battery pack, including a box body and a plurality of battery cells. The plurality of battery cells are accommodated in the box body or a sealed space is formed between the battery cells and the box body. Each battery cell includes a cell body and an electrical connector provided on the cell body. A first flow channel is formed between two adjacent battery cells or between a battery cell and the inner wall of the box body. The first flow channel is used to accommodate the heat transfer medium, at least a part of the cell body is immersed in the heat transfer medium, and the contact area between the electrical connector and the heat transfer medium is zero. The electrical connector is a pole and / or a high-voltage conductive bar between the poles.

[0005] The poles include a positive pole and a negative pole. The high-voltage conductive bar between the poles refers to the high-voltage conductive bar connected between the positive pole of one battery cell and the negative pole of another battery cell.

[0006] For the battery pack provided by the present application, at least part of the core is immersed in the heat transfer medium, that is, the battery pack adopts an immersion liquid cooling scheme, so that the heat transfer medium is in direct contact with the core for heat exchange. Compared with the liquid cooling scheme of the liquid cooling plate, the volume of the heat transfer medium in the battery pack is increased, which is beneficial to improving the heat transfer capacity and heat transfer efficiency of the battery pack. Since the heat transfer capacity and heat transfer efficiency of the battery pack are improved, the heat generated by the battery pack during fast charging or thermal runaway can be effectively and timely removed, which is beneficial to improving the safety and reliability of the battery pack.

[0007] A first flow channel is formed between two adjacent battery cells and / or between the battery cell and the inner wall of the box body, and at least part of the core is immersed in the heat transfer medium, that is, the battery pack of the present application adopts a semi-immersion liquid cooling scheme. In this way, compared with the full-immersion liquid cooling scheme in which the box body is completely filled with the heat transfer medium, the semi-immersion liquid cooling scheme reduces the volume of the heat transfer medium, which is beneficial to increasing the temperature rise or fall rate of the heat transfer medium and shortening the time to reach the required temperature.

[0008] In addition, since the contact area between the electrical connector and the heat transfer medium is zero, liquid-electric separation is achieved, avoiding or reducing the risk of the heat transfer medium being ionized by the charged electrical connector, and improving the safety and reliability of the battery pack. If the heat transfer medium is ionized, it will damage the insulation inside the battery pack, and there will be a risk of arc ignition inside the battery pack. If the heat transfer medium is ionized, it will change the physical properties of the heat transfer medium and affect the heat transfer efficiency between the heat transfer medium and the battery cell. Moreover, the electrical connector usually has an irregular shape. Since the electrical connector does not contact the heat transfer medium, the electrical connector will not impede the flow of the heat transfer medium, thereby effectively reducing the flow resistance of the heat transfer medium and improving the heat transfer uniformity of the battery pack.

[0009] According to the first aspect, in a possible implementation, the first flow channel includes a straight flow channel. The straight flow channel includes a first liquid inlet and a first liquid outlet, and the straight flow channel extends along a first direction. The first liquid inlet of the straight flow channel is located at one end of the straight flow channel in the first direction for inputting the heat transfer medium, and the first liquid outlet of the straight flow channel is located at the other end of the straight flow channel in the first direction for outputting the heat transfer medium.

[0010] In this possible implementation, the straight flow channel can reduce the flow resistance during the flow of the heat transfer medium and improve the heat transfer uniformity of the battery pack.

[0011] According to the first aspect, in a possible implementation, the number of the straight flow channels is at least two, and at least two straight flow channels are arranged along a second direction perpendicular to the first direction.

[0012] According to the first aspect, in a possible implementation, the first flow channel includes a curved flow channel, the curved flow channel includes a first liquid inlet and a first liquid outlet, the first liquid inlet of the curved flow channel is used for inputting a heat exchange working medium, and the first liquid outlet of the curved flow channel is used for outputting the heat exchange working medium.

[0013] In this possible implementation, the curved flow channel can improve the stability of the heat exchange working medium flowing between the battery cells.

[0014] According to the first aspect, in a possible implementation, the curved flow channel further includes a first part and a second part that are connected and communicate with each other. The first part and the second part are arranged along a second direction. The first liquid inlet of the curved flow channel is provided at the first part, and the first liquid outlet of the curved flow channel is provided at the second part.

[0015] In this possible implementation, the first liquid inlet is provided at the first part, the first liquid outlet is provided at the second part, and the first part and the second part are arranged along the second direction. In this way, there is a distance between the first liquid inlet and the first liquid outlet in the second direction, which is beneficial to extending the heat exchange path of the heat exchange working medium on the battery cells and improving the heat exchange effect between the heat exchange working medium and the battery cells.

[0016] According to the first aspect, in a possible implementation, the first liquid inlet of the curved flow channel is provided at the first end of the first part in a first direction. The second end of the first part in the first direction is connected to the first end of the second part in the first direction. The first liquid outlet of the curved flow channel is provided at the second end of the second part in the first direction, and the first direction is perpendicular to the second direction.

[0017] In this possible implementation, both the first part and the second part extend along the first direction, the first direction is perpendicular to the second direction, and there is a distance between the first liquid inlet and the first liquid outlet in the first direction, which is beneficial to extending the heat exchange path of the heat exchange working medium on the battery cells and improving the heat exchange effect between the heat exchange working medium and the battery cells.

[0018] According to the first aspect, in a possible implementation, the curved flow channel further includes a third part. The first part, the third part, and the second part are arranged in sequence along the second direction. The first end of the third part in the first direction is connected to the second end of the first part, and the second end of the third part in the first direction is connected to the first end of the second part. The first end of the first part, the second end of the third part, and the first end of the second part are arranged in sequence in the second direction.

[0019] In this possible implementation, the curved flow channel is in an "S" shape.

[0020] According to the first aspect, in a possible implementation, the battery pack further includes a flow guiding strip fixed between two adjacent battery cells. The flow guiding strip, the battery cells, and the inner wall of the box body enclose the first flow channel.

[0021] In a possible implementation of this type, a first flow channel is formed by the diversion bar, the battery cell, and the inner wall of the box body. The structure is simple and convenient to manufacture. In addition, the diversion bar can support the battery cell when it expands, reducing the possibility of deformation of the battery cell and the first flow channel, reducing the impact of the cyclic expansion of the battery cell on the first flow channel, and improving the stability of the heat exchange working medium when flowing through the first flow channel.

[0022] According to the first aspect, in a possible implementation, a second flow channel is provided on the inner wall of the box body. The second flow channel is used to accommodate the heat exchange working medium. The second flow channel includes a connected opening, a second liquid inlet, and a second liquid outlet. The second liquid inlet is used to input the heat exchange working medium, and the second liquid outlet is used to output the heat exchange working medium. Each battery cell covers a corresponding opening.

[0023] In a possible implementation of this type, since the second flow channel can also allow the heat exchange working medium to flow through, in this way, the heat exchange area between the heat exchange working medium and the battery cell is increased, and the heat exchange efficiency of the battery pack is improved.

[0024] In addition, the first flow channel and the second flow channel may not communicate with each other, and the heat exchange working medium in the first flow channel and the heat exchange working medium in the second flow channel do not flow through each other and can flow separately. Through the partition design of the heat exchange working medium, when there is a leakage of the heat exchange working medium at a certain place in the battery pack, for example, when the vehicle scrapes the bottom, resulting in the failure of the bottom seal of the battery pack, the heat exchange working medium in the first flow channel of the battery pack leaks and cannot work, but the heat exchange working medium in the second flow channel does not leak and can still play a heat protection role, improving the robustness of the liquid cooling system. In addition, the immersion heat exchange working medium is restricted to flow orderly between the first side and the bottom surface of the battery cell, which can reduce the volume of the immersion heat exchange working medium and also reduce the risk of leakage of the battery pack to the outside during long-term use.

[0025] According to the first aspect, in a possible implementation, the box body includes a main body and a plurality of support pads. The plurality of support pads are arranged at intervals on the inner wall of the main body, and a second flow channel is formed between every two adjacent support pads. Each battery cell is connected to the corresponding two adjacent support pads.

[0026] In a possible implementation of this type, a plurality of second flow channels are formed by arranging a plurality of support pads at intervals on the inner wall of the main body. The flow channel structure is simple, simplifies the preparation of the box body, and reduces the manufacturing cost of the battery pack. In addition, the support pads can support the battery cell when it expands, reducing the possibility of deformation of the battery cell and the second flow channel, reducing the impact of the cyclic expansion of the battery cell on the second flow channel, and improving the stability of the heat exchange working medium when flowing through the second flow channel.

[0027] According to the first aspect, in a possible implementation, the box body includes a main body and a partition member received in the main body. The partition member and the inner wall of the main body enclose a second flow channel and a receiving cavity that are separately arranged. The partition member is provided with a plurality of openings, and a plurality of battery cells are received in the receiving cavity.

[0028] In a possible implementation of this type, a second flow channel is directly formed by the separator and the main body, and a plurality of openings are provided on the separator. The flow channel structure is simple, which simplifies the preparation of the box body and reduces the manufacturing cost of the battery pack.

[0029] According to the first aspect, in a possible implementation, the second flow channel extends along a first direction. In the first direction, the length of the second flow channel is greater than the length of the battery cells, and a part of the opening of the second flow channel is exposed outside the plurality of battery cells.

[0030] In a possible implementation of this type, when a battery cell undergoes thermal runaway and gas is ejected from the bottom surface of the battery cell, since a part of the opening of the second flow channel is exposed outside the plurality of battery cells, the gas passes through the second flow channel and is exhausted from the exposed opening of the second flow channel, improving the smoothness of thermal runaway exhaust and reducing the possibility of the battery pack explosion, thereby improving the safety of the battery pack.

[0031] According to the first aspect, in a possible implementation, the box body is further provided with a connecting flow channel that connects the first flow channel and the second flow channel.

[0032] In a possible implementation of this type, the first flow channel and the second flow channel can also be connected through a connecting channel, so that the heat exchange working medium can flow between the first flow channel and the second flow channel, that is, the heat exchange working medium forms an integrated flow within the battery pack.

[0033] According to the first aspect, in a possible implementation, the second liquid outlet is connected to the connecting flow channel; after the heat exchange working medium passes through the second liquid inlet, the second liquid outlet, and the connecting flow channel, it enters the first flow channel.

[0034] According to the first aspect, in a possible implementation, the battery pack further includes a first manifold, a second manifold, a third manifold, a fourth manifold, a first multi-way valve, and a second multi-way valve. The first manifold, the first flow channel, and the second manifold are connected; the third manifold, the second flow channel, and the fourth manifold are connected; the first multi-way valve is connected to the first manifold and the third manifold, and the second multi-way valve is connected to the second manifold and the fourth manifold; the first multi-way valve and the second multi-way valve are connected, and the first multi-way valve and the second multi-way valve are used to control the on-off of the third manifold, the fourth manifold, the first manifold, and the second manifold.

[0035] In a possible implementation of this type, the flow of the heat exchange working medium in the first flow channel and the second flow channel is controlled by a multi-way valve, reducing the number of valves and pipelines used and improving the control flexibility. The first multi-way valve and the second multi-way valve can be connected through a pipeline. In this way, the heat exchange working medium in the first flow channel and the second flow channel can share heat exchangers, pumps, etc., reducing the number of heat exchangers and pumps used and simplifying the structure of the liquid cooling system.

[0036] According to the first aspect, in a possible implementation, the battery pack includes a first operating mode and a second operating mode. By controlling the second multi-way valve and the first multi-way valve, the battery pack can be switched between the first operating mode and the second operating mode. When the battery pack is in the first operating mode, the heat exchange working medium can flow in the first flow channel and the second flow channel. When the battery pack is in the second operating mode, the heat exchange working medium can flow in one of the first flow channel and the second flow channel.

[0037] In this possible implementation, when the battery pack is in the first operating mode, the heat exchange working medium can flow in the first flow channel and the second flow channel, and the heat exchange working medium in the first flow channel and the second flow channel can exchange heat with the battery cells. In this way, the volume of the heat exchange working medium for heat exchange is large, and the heat exchange capacity of the battery pack is strong, which is beneficial to improving the heat exchange efficiency of the battery pack.

[0038] When the battery pack is in the second operating mode, since the heat exchange working medium in one of the first flow channel and the second flow channel exchanges heat with the battery cells, the volume of the heat exchange working medium is small, which is beneficial to increasing the rate of temperature rise or temperature drop. In this way, the operating mode of the battery pack can be selected according to the specific application scenario of the liquid cooling system, which is beneficial to reducing the energy consumption of the liquid cooling system.

[0039] According to the first aspect, in a possible implementation, the first manifold, the second manifold, the third manifold, the fourth manifold, the first multi-way valve and the second multi-way valve are all located inside the box.

[0040] In this possible implementation, the first manifold, the second manifold, the third manifold, the fourth manifold, the first multi-way valve and the second multi-way valve are all located inside the box, so that the first manifold, the second manifold, the third manifold, the fourth manifold, the first multi-way valve and the second multi-way valve can all be integrated in the battery pack. In this way, when assembling the battery pack to an electrical device such as a vehicle or an energy storage system, only simple pipeline connections with heat exchangers, pumps, etc. outside the battery pack are required.

[0041] According to the first aspect, in a possible implementation, the core body includes a battery cell top surface, a battery cell bottom surface and a battery cell side surface. The battery cell top surface and the battery cell bottom surface are arranged opposite to each other, the battery cell side surface is connected between the battery cell top surface and the battery cell bottom surface, electrical connectors are arranged on the battery cell top surface, the battery cell side surface includes two first side surfaces and two second side surfaces, the two first side surfaces are opposite and parallel to each other, the two second side surfaces are opposite and parallel to each other, and the area of the first side surface is larger than the area of the second side surface. The first side surfaces of multiple battery cells are arranged, and a first flow channel is formed between adjacent two first side surfaces of the battery cells.

[0042] In some possible implementation manners of this species, since the first flow channel is formed between the larger side surfaces of two adjacent battery cells, the contact area between the battery cells and the heat exchange working medium is increased, and the heat exchange efficiency of the battery pack is improved.

[0043] According to the first aspect, in some possible implementation manners, the second side surfaces of multiple battery cells are arranged, and a first flow channel is formed between the second side surfaces of adjacent battery cells.

[0044] According to the first aspect, in some possible implementation manners, a first flow channel is formed between the second side surface of the battery cell and the inner wall of the box body.

[0045] In a second aspect, an embodiment of the present application further provides a liquid cooling system, including a heat exchanger, a pump, and a battery pack according to the first aspect. The heat exchanger, the pump, and the first flow channel of the battery pack are connected through pipelines.

[0046] Since the battery pack adopts a semi-immersed liquid cooling scheme to adjust the temperature, while improving the heat exchange efficiency of the liquid cooling system, the energy consumption of the liquid cooling system can be reduced.

[0047] In a third aspect, an embodiment of the present application further provides a vehicle, including a vehicle body and a liquid cooling system according to the second aspect. The liquid cooling system is arranged on the vehicle body.

[0048] Since the battery pack adopts a semi-immersed liquid cooling scheme to adjust the temperature, while improving the heat exchange efficiency of the liquid cooling system, the energy consumption of the liquid cooling system can be reduced. In addition, the contact area between the electrical connector and the heat exchange working medium is zero, realizing liquid-electric separation, avoiding or reducing the risk of the heat exchange working medium being ionized by the charged electrical connector, and improving the safety and reliability of the battery pack and the vehicle.

[0049] In a fourth aspect, an embodiment of the present application further provides an energy storage system, including the liquid cooling system according to the second aspect. Description of the Drawings

[0050] Figure 1 A schematic diagram of a vehicle provided by some embodiments of the present application;

[0051] Figure 2 A schematic diagram of the structure of a battery pack provided by some embodiments of the present application;

[0052] Figure 3 A partial schematic diagram of the structure of a battery pack provided by some embodiments of the present application;

[0053] Figure 4 A schematic diagram of the first flow channel of a battery pack provided by some embodiments of the present application;

[0054] Figure 5 A schematic diagram of the first flow channel of a battery pack provided by some embodiments of the present application;

[0055] Figure 6 Schematic diagram of a first flow channel formed between the inner wall of the battery pack housing and the second side of the battery cell provided in some embodiments of the present application;

[0056] Figure 7 Schematic diagram of the opening of the second flow channel of the battery pack provided in some embodiments of the present application exposing the battery cell;

[0057] Figure 8 Schematic diagram of a second flow channel formed between the main body of the battery pack and the partition provided in some embodiments of the present application;

[0058] Figure 9 Schematic diagram of the battery cell of the battery pack provided in some embodiments of the present application being horizontally placed in the housing;

[0059] Figure 10 Schematic diagram of the pipeline of the liquid cooling system provided in some embodiments of the present application;

[0060] Figure 11 Schematic diagram of the circulation of the heat exchange working medium when the battery pack provided in some embodiments of the present application is in the first working mode;

[0061] Figure 12 Schematic diagram of the circulation of the heat exchange working medium when the battery pack provided in some embodiments of the present application is in the first sub - mode;

[0062] Figure 13 Schematic diagram of the circulation of the heat exchange working medium when the battery pack provided in some embodiments of the present application is in the second sub - mode;

[0063] Figure 14 Schematic diagram of the first flow channel and the second flow channel of the battery pack provided in some embodiments of the present application being connected through a connecting flow channel. Detailed implementation manners

[0064] Figure 1 Schematic diagram of a vehicle provided in some embodiments of the present application. The vehicle includes a liquid cooling system 1 and a vehicle body 2. The liquid cooling system 1 is arranged on the vehicle body 2. The vehicle can be a new energy vehicle or an ordinary vehicle.

[0065] The liquid cooling system 1 includes a battery pack 101, a heat exchanger 102, and a pump 103. The battery pack 101 is used to provide electric energy. The battery pack 101, the heat exchanger 102, and the pump 103 are connected through pipelines to form a heat exchange loop. The heat exchanger 102 is used to adjust the temperature of the battery pack 101. The pump 103 is used to drive the heat exchange working medium to circulate in the heat exchange loop to achieve the temperature adjustment of the battery pack 101. The heat exchanger 102 can include an evaporator, a condenser, etc. It can be understood that the liquid cooling system 1 can also include other necessary or non - necessary components such as a compressor.

[0066] It can be understood that the liquid cooling system 1 can also be applied to an energy storage system or other electrical equipment.

[0067] Please refer to Figure 2 , the battery pack 101 includes a box body 20 and a plurality of battery cells 40. The plurality of battery cells 40 can be received in the box body 20. The battery cell 40 includes a cell body 42 and an electrical connection member 44 provided on the cell body 42. The electrical connection member 44 can be a terminal 442 and / or a high-voltage conductive busbar 444. The terminal 442 protrudes from the cell body 42 and is electrically connected to the cell body 42. The terminal 442 includes a positive terminal 4422 and a negative terminal 4424. The positive terminal 4422 of one battery cell 40 is electrically connected to the negative terminal 4424 of another battery cell 40 through the high-voltage conductive busbar 444. The negative terminal 4424 of one battery cell 40 is electrically connected to the positive terminal 4422 of another battery cell 40 through the high-voltage conductive busbar 444. That is, the high-voltage conductive busbar 444 refers to the high-voltage conductive busbar between the terminals 442.

[0068] In the battery pack 101 provided by the present application, a first flow channel 201 is formed between two adjacent battery cells 40 or between the battery cell 40 and the inner wall of the box body 20. The first flow channel 201 is used to accommodate the heat transfer medium 200. At least a part of the cell body 42 is immersed in the heat transfer medium 200, and the contact area between the electrical connection member 44 and the heat transfer medium 200 is zero. It can be understood that in some embodiments, the plurality of battery cells 40 may not be received in the box body 20, and the battery cell 40 and the box body 20 can form a sealed space, and the first flow channel 201 is formed between the battery cell 40 and the inner wall of the box body 20.

[0069] If the heat transfer medium fills the inside of the entire battery pack and directly contacts the entire battery cell for heat exchange, the terminals and the high-voltage conductive busbars between the terminals will directly contact the heat transfer medium. On the one hand, since the heat transfer medium directly contacts the terminals and / or the high-voltage conductive busbars on the battery cell, as the use time increases, there is a risk that the heat transfer medium will be ionized by high voltage. If the heat transfer medium is ionized, the insulation inside the battery pack will be damaged, and there will be a risk of arcing and sparking inside the battery pack. If the heat transfer medium is ionized, the physical properties of the heat transfer medium will be changed, affecting the heat exchange efficiency between the heat transfer medium and the battery cell. On the other hand, since the heat transfer medium fills the inside of the entire battery pack, the volume of the heat transfer medium is large, resulting in a low temperature rise rate of the battery pack when heating the battery cells inside the battery pack, or a low temperature drop rate of the battery pack when cooling the battery cells of the battery pack. In this way, it takes a long time to reach the required operating temperature of the battery pack, which will increase the energy consumption of the vehicle.

[0070] In the battery pack 101 provided by the present application, at least a part of the core 42 is immersed in the heat exchange working fluid 200. That is, the battery pack 101 adopts an immersion liquid cooling scheme, enabling the heat exchange working fluid 200 to directly contact the core 42 for heat exchange. Compared with the liquid cooling scheme of the liquid cooling plate, the volume of the heat exchange working fluid 200 in the battery pack 101 is increased, which is beneficial to improving the heat exchange capacity and heat exchange efficiency of the battery pack 101. Since the heat exchange capacity and heat exchange efficiency of the battery pack 101 are improved, the heat generated by the battery pack 101 during fast charging or thermal runaway can be effectively and timely removed, thus being beneficial to improving the safety and reliability of the battery pack 101.

[0071] A first flow channel is formed between two adjacent battery cells 40 and / or between the battery cell 40 and the inner wall of the box body 20. At least a part of the core 42 is immersed in the heat exchange working fluid 200. That is, the battery pack 101 of the present application adopts a semi-immersion liquid cooling scheme. In this way, the volume of the heat exchange working fluid 200 is reduced, which is beneficial to increasing the rate of temperature rise or fall of the heat exchange working fluid 200 and shortening the time to reach the required temperature.

[0072] In addition, since the contact area between the electrical connection member 44 and the heat exchange working fluid 200 is zero, liquid-electric separation is achieved, avoiding the risk of the heat exchange working fluid 200 being ionized by the charged electrical connection member 44. In addition, electrical connection members 44 such as the pole 442 and the high-voltage conductive busbar 444 usually have irregular shapes. Since the electrical connection member 44 does not contact the heat exchange working fluid 200, the electrical connection member 44 will not impede the flow of the heat exchange working fluid 200, thus effectively reducing the flow resistance of the heat exchange working fluid 200 and improving the heat exchange uniformity of the battery pack 101.

[0073] The heat exchange working fluid 200 can be a coolant, such as water, ethylene glycol solution, propylene glycol solution or fluorinated liquid, etc. The heat exchange working fluid 200 can also include a gas. The working fluid can be a single component or can be composed of at least two heat exchange working fluids 200 mixed together (for example, a mixed liquid composed of at least two coolants). The heat exchange working fluid 200 can remain single-phase (i.e., no phase change occurs) during the flow process, or can be two-phase (i.e., converting between the liquid phase and the gas phase). It can be understood that the type of heat exchange working fluid required can be selected according to needs.

[0074] In some embodiments of the present application, the box body 20 includes a main body 22 and a plurality of support pads 24. The main body 22 is used to accommodate a plurality of battery cells 40. The plurality of support pads 24 are arranged at intervals on the bottom wall of the main body 22 and are located inside the main body 22, and are used to support the plurality of battery cells 40. The main body 22 includes a top wall, a bottom wall and a side wall, and the top wall and the bottom wall are oppositely arranged. The side wall is connected between the bottom wall and the top wall.

[0075] Please refer to Figure 3, the core body 42 is generally cube-shaped. The core body 42 includes a battery cell top surface 422, a battery cell bottom surface 424, and battery cell side surfaces 426. The battery cell top surface 422 and the battery cell bottom surface 424 are disposed opposite to each other. The battery cell side surfaces 426 are connected between the battery cell top surface 422 and the battery cell bottom surface 424. The electrical connection member 44 is disposed on the battery cell top surface 422. The battery cell side surfaces 426 include two first side surfaces 4262 and two second side surfaces 4264. The two first side surfaces 4262 are opposite and parallel to each other. The two second side surfaces 4264 are opposite and parallel to each other. The area of the first side surface 4262 is larger than the area of the second side surface 4264. The area of the battery cell bottom surface 424 is smaller than the area of the first side surface 4262. The first side surfaces 4262 of multiple battery cells 40 are arranged along the second direction Z. At least one first flow channel 201 is formed between the first side surfaces 4262 of two adjacent battery cells 40. Since the first flow channel 201 is formed between the relatively larger side surfaces of two adjacent battery cells 40, the contact area between the battery cells 40 and the heat exchange working fluid 200 is increased, and the heat exchange efficiency of the battery pack 101 is improved. Exemplarily, Figure 3 The dotted arrow in it indicates the flow direction of the heat exchange working fluid 200 in the battery pack 101.

[0076] In some embodiments of the present application, the two second side surfaces 4264 are disposed opposite to each other along the first direction X. The battery cell top surface 422 and the battery cell bottom surface 424 are spaced apart along the second direction Z. The two first side surfaces 4262 are disposed opposite to each other along the third direction Y. The first direction X is perpendicular to the third direction Y. The third direction Y is perpendicular to the second direction Z. The first direction X is perpendicular to the second direction Z. The battery cell top surface 422, the battery cell bottom surface 424, and the bottom wall of the box body 20 are arranged along the second direction Z. That is, the battery cells 40 are vertically placed in the box body 20. It can be understood that the present application does not limit the shape of the core body 42 to be cube-shaped, and the core body 42 can also be other shapes, such as a cylinder, etc. It can be understood that the first direction is different from the second direction, the second direction is different from the third direction, and the third direction is different from the first direction.

[0077] It can be understood that in the first direction X, the first side surfaces 4262 of the first and last battery cells 40 among multiple battery cells 40 can form a first flow channel 201 with the inner wall of the box body 20 to increase the contact area between the first and last battery cells 40 among multiple battery cells 40 and the heat exchange working fluid 200.

[0078] The battery pack 101 further includes a guide strip 50 (such as Figure 4As shown, the flow guide bar 50 is fixed between two adjacent first side surfaces 4262. The flow guide bar 50, the battery cell 40, and the inner wall of the box body 20 enclose a first flow channel 201. By enclosing the first flow channel 201 with the flow guide bar 50, the battery cell 40, and the inner wall of the box body 20, the structure is simple and manufacturing is convenient. In addition, the flow guide bar 50 can support the battery cell 40 when it expands, reducing the possibility of deformation of the battery cell 40 and the first flow channel 201, and improving the stability of the heat exchange working medium flowing in the first flow channel 201. It can be understood that the number of the first flow channels 201 in this application is not limited.

[0079] The first flow channel 201 includes a straight flow channel and / or a curved channel. As Figure 4 shown, the first flow channel 201 includes a straight flow channel. The straight flow channel includes a first liquid inlet 2011 and a first liquid outlet 2013. The straight flow channel extends along the first direction X. The first liquid inlet 2011 of the straight flow channel is located at one end of the straight flow channel in the first direction X for inputting the heat exchange working medium 200, and the first liquid outlet 2013 of the straight flow channel is located at the other end of the straight flow channel in the first direction X for outputting the heat exchange working medium 200. The straight flow channel can reduce the flow resistance of the heat exchange working medium 200 during the flowing process and improve the heat exchange uniformity of the battery pack 101.

[0080] Figure 4 Exemplarily shown in [the figure] is that the number of the straight flow channels is two, and the two straight flow channels are arranged along the third direction Y perpendicular to the first direction X. Increasing the number of the straight flow channels is beneficial to improving the heat exchange effect between the heat exchange working medium and the battery cell. It can be understood that the number of the straight flow channels can be one, and the number of the straight flow channels can also be at least two. The number and arrangement direction of the straight flow channels in this application are not limited.

[0081] In one embodiment, as Figure 5As shown, the first flow channel 201 includes a bent flow channel, which can improve the uniformity and stability of the heat exchange working medium 200 flowing between the battery cells 40. The bent flow channel is generally in an "S" shape. The bent flow channel includes a first part 2014, a second part 2015, a third part 2016, a first liquid inlet 2011 and a first liquid outlet 2013. The first part 2014, the second part 2015 and the third part 2016 all extend along the first direction X. The first part 2014, the third part 2016 and the second part 2015 are arranged along the third direction Y. The first direction X is perpendicular to the third direction Y. The first liquid inlet 2011 is provided at the first end of the first part 2014 in the first direction X for inputting the heat exchange working medium 200. The second end of the first part 2014 in the first direction X is communicated with the first end of the second part 2015 in the first direction X. The first liquid outlet 2013 of the bent flow channel is provided at the second end of the second part 2015 in the first direction X, and the first direction X is perpendicular to the third direction Y. The first end of the first part 2014, the second end of the third part 2016 and the first end of the second part 2015 are arranged in sequence in the third direction Y. The first part 2014 can be provided on one side of the first side surface 4262 close to the bottom surface 424 of the battery cell, and the second part 2015 can be provided on one side of the first side surface 4262 close to the top surface 422 of the battery cell.

[0082] It can be understood that the present application does not limit the shape of the bent flow channel. For example, the bent flow channel can be in a "C" shape, a "Z" shape, etc.

[0083] In some embodiments of the present application, a first flow channel 201 is formed between the battery cell 40 and the inner wall of the box body 20 for flowing the heat exchange working medium 200. For example, as Figure 6 shown, a first flow channel 201 is formed between the second side surface 4264 of the battery cell 40 and the inner wall of the box body 20. It can be understood that the second side surfaces 4264 of multiple battery cells 40 can be arranged, and a first flow channel 201 is formed between adjacent second side surfaces 4264 of the battery cells 40.

[0084] Please refer back to Figure 2 and Figure 3, a second flow channel 203 is provided on the inner wall of the box body 20, and the second flow channel 203 is used to accommodate the heat exchange working medium 200. The second flow channel 203 includes a connected opening 2031, a second liquid inlet 2033 and a second liquid outlet 2035. The second liquid inlet 2033 is used to input the heat exchange working medium 200. The second liquid outlet 2035 is used to output the heat exchange working medium 200. Each battery cell 40 covers a corresponding opening 2031 to enable the battery cell 40 to exchange heat with the heat exchange working medium 200 in the second flow channel 203. In some embodiments of the present application, the bottom surface 424 of the battery cell covers the corresponding opening 2031. The second flow channel 203 extends along the first direction X. Since the second flow channel 203 can also circulate the heat exchange working medium, in this way, the heat exchange area between the heat exchange working medium 200 and the battery cell 40 is increased, and the heat exchange efficiency of the battery pack 101 is improved.

[0085] In some embodiments of the present application, the first flow channel 201 and the second flow channel 203 may not communicate with each other, and the heat exchange working medium 200 in the first flow channel 201 and the heat exchange working medium 200 in the second flow channel 203 do not flow to each other and can flow separately. For example, the liquid cooling system 1 includes independent first and second flow paths, and heat exchangers 102, pumps 103, etc. are provided on each flow path. The first flow channel 201 is located in the first flow path, and the second flow channel 203 is located in the second flow path. The heat exchange working medium 200 in the first flow channel 201 only flows in the first flow path where the first flow channel 201 is located and will not flow to the second flow channel 203, and the heat exchange working medium 200 in the second flow channel 203 only flows in the second flow path where the second flow channel 203 is located and will not flow to the first flow channel 201. Through the partition design of the heat exchange working medium 200, when the heat exchange working medium 200 leaks somewhere in the battery pack 101, for example, the bottom seal of the battery pack 101 fails due to the vehicle scraping the bottom, causing the heat exchange working medium 200 in the second flow channel 203 of the battery pack 101 to leak and unable to work, but the heat exchange working medium 200 in the first flow channel 201 does not leak and can still play a heat protection role, thereby improving the robustness of the liquid cooling system 1. In addition, the immersion heat exchange working medium 200 is restricted to flow orderly in the first flow channel 201 and the second flow channel 203, which can reduce the volume of the immersion heat exchange working medium 200 and also reduce the risk of leakage of the battery pack 101 to the outside of the battery pack 101 during long-term use.

[0086] In some embodiments of the present application, a second flow channel 203 is formed between every two adjacent support pads 24, and each battery cell 40 is connected to the two adjacent support pads 24 corresponding thereto. The first side surfaces 4262 of the two battery cells 40 and the side of the support pad 24 facing away from the main body 22 together enclose the first flow channel 201. By arranging a plurality of support pads 24 at intervals on the inner wall of the main body 22 to form a plurality of second flow channels 203, the structure is simple, the preparation of the box body 20 is simplified, and the manufacturing cost of the battery pack 101 is reduced.

[0087] In some embodiments of the present application, please refer to Figure 7 , in the first direction X, the length of the second flow channel 203 is greater than the length of the battery cell 40, and a part of the opening 2031 of the second flow channel 203 is exposed outside the plurality of battery cells 40. If a battery cell 40 undergoes thermal runaway, that is, when the battery cell 40 expands and ejects gas from the bottom surface 424 of the battery cell, since a part of the opening 2031 of the second flow channel 203 is exposed outside the plurality of battery cells 40, the gas passes through the second flow channel 203 and exhausts from the exposed opening 2031 of the second flow channel 203, improving the smoothness of thermal runaway exhaust and reducing the possibility of explosion of the battery pack 101, thereby improving the safety of the battery pack 101.

[0088] The battery cell 40 further includes a battery cell explosion-proof valve 46, and the battery cell explosion-proof valve 46 (as Figure 2 shown) is disposed on the bottom surface 424 of the battery cell and is disposed towards the opening 2031. In other words, the orthographic projection of the battery cell explosion-proof valve 46 on the box body 20 in the second direction Z is located in the second flow channel 203. If a battery cell 40 undergoes thermal runaway, the battery cell explosion-proof valve 46 on the thermally runaway battery cell 40 sprays gas into the corresponding second flow channel 203. Since a part of the opening 2031 of the second flow channel 203 is exposed outside the plurality of battery cells 40, the gas passes through the second flow channel 203 and exhausts from the exposed opening 2031 of the second flow channel 203, improving the smoothness of thermal runaway exhaust and further reducing the possibility of explosion of the battery pack 101, thereby improving the safety of the battery pack 101.

[0089] It can be understood that the present application does not limit the setting manner of the second flow channel 203. In some embodiments of the present application, as Figure 8 shown, the box body 20 includes a main body 22 and a partition member 26 received in the main body 22. The partition member 26 and the inner wall of the main body 22 define a second flow channel 203 and a receiving cavity 205 that are separately provided. The partition member 26 is provided with a plurality of openings 2031, and a plurality of battery cells 40 are received in the receiving cavity 205, and the battery cells 40 cover the openings 2031. The battery pack 101 further includes a battery pack explosion-proof valve 53, and the battery pack explosion-proof valve 53 is disposed on the outer wall of the main body 22. The battery pack explosion-proof valve 53 is used to spray the gas in the second flow channel 203 when the gas pressure in the second flow channel 203 is too high. When the battery cells 40 in the battery pack 101 undergo thermal runaway, the gas ejected from the bottom surface 424 of the battery cells will flow into the second flow channel 203. When the gas pressure in the second flow channel 203 exceeds the range that the battery pack explosion-proof valve 53 can withstand, the battery pack explosion-proof valve 53 releases the gas in the second flow channel 203, thereby reducing the possibility of explosion of the battery pack 101 and improving the safety of the battery pack 101.

[0090] In some embodiments of the present application, as Figure 9As shown, one second side 4264 of the battery cell 40 can cover the opening 2031 of the corresponding second flow channel 203. The contact area between the electrical connector 44 of the battery cell 40 and the heat exchange working fluid 200 is zero, that is, the battery cell 40 is horizontally placed in the box body 20. A battery cell explosion-proof valve 46 is provided on the top surface 422 of the battery cell, and the top surface 422 of the battery cell faces the side wall of the box body 20. One second side 4264 of the battery cell 40 is arranged on the side of the battery cell 40 facing the support pad 24.

[0091] Please refer to Figure 10 , in some embodiments of the present application, the battery pack 101 further includes a first manifold 61, a second manifold 62, a third manifold 63, a fourth manifold 64, a first multi-way valve 671 and a second multi-way valve 672. The first manifold 61, the first flow channel 201 and the second manifold 62 are connected to enable the heat exchange working fluid 200 to flow in each first flow channel 201. The third manifold 63, the second flow channel 203 and the fourth manifold 64 are connected to enable the heat exchange working fluid 200 to flow in each second flow channel 203. The first multi-way valve 671 is connected to the heat exchanger 102 outside the battery pack 101 through a pipeline, and the second multi-way valve 672 is connected to the pump 103 through a pipeline. The first multi-way valve 671 is connected to the first manifold 61 and the third manifold 63, and the second multi-way valve 672 is connected to the second manifold 62 and the fourth manifold 64. The first multi-way valve 671 and the second multi-way valve 672 are connected to each other, and the first multi-way valve 671 and the second multi-way valve 672 are used to control the on-off of the third manifold 63, the fourth manifold 64, the first manifold 61 and the second manifold 62. By controlling the flow of the heat exchange working fluid 200 in the first flow channel 201 and the second flow channel 203 through the multi-way valve, the number of valves and pipelines used is reduced, and the control flexibility is improved.

[0092] The first multi-way valve 671 and the second multi-way valve 672 can be connected through a pipeline. In this way, the heat exchange working fluid 200 in the first flow channel 201 and the second flow channel 203 can share the heat exchanger 102, the pump 103, etc., reducing the number of heat exchangers 102 and pumps 103 used and simplifying the structure of the liquid cooling system 1. It can be understood that a connecting flow channel is arranged on the box body 20 or other structures in the battery pack 101, and the first multi-way valve 671 is connected to the second multi-way valve 672 through the connecting flow channel.

[0093] In some embodiments of the present application, the first manifold 61, the second manifold 62, the third manifold 63, the fourth manifold 64, the first multi-way valve 671 and the second multi-way valve 672 are all located within the box body 20, enabling the first manifold 61, the second manifold 62, the third manifold 63, the fourth manifold 64, the first multi-way valve 671 and the second multi-way valve 672 to be integrated within the battery pack 101. Thus, when assembling the battery pack 101 to an electrical device such as a vehicle or an energy storage system, only simple pipeline connections need to be made with the heat exchanger 102, the pump 103, etc. outside the battery pack 101. It can be understood that the first manifold 61, the second manifold 62, the third manifold 63, the fourth manifold 64, the first multi-way valve 671 and the second multi-way valve 672 may also be located outside the battery pack 101.

[0094] The battery pack 101 includes a first operating mode (such as Figure 11 shown) and a second operating mode (such as Figure 12 and Figure 13 shown). By controlling the opening and closing of each valve port in the first multi-way valve 671 and the second multi-way valve 672, the battery pack 101 can be switched between the first operating mode and the second operating mode. When the battery pack 101 is in the first operating mode, driven by the pump 103, the heat exchange working fluid 200 can flow within the first flow channel 201 and the second flow channel 203 to exchange heat with the battery cells 40. When the battery pack 101 is in the second operating mode, driven by the pump 103, the heat exchange working fluid 200 can flow in one of the first flow channel 201 and the second flow channel 203 to exchange heat with the battery cells 40.

[0095] When the battery pack 101 is in the first operating mode, the heat exchange working fluid 200 can flow within the first flow channel 201 and the second flow channel 203, and the heat exchange working fluid 200 within the first flow channel 201 and the second flow channel 203 can exchange heat with the battery cells 40. In this way, the volume of the heat exchange working fluid 200 for heat exchange is relatively large, and the heat exchange capacity of the battery pack 101 is strong, which is beneficial to improving the heat exchange efficiency of the battery pack 101. When the battery pack 101 is in the second operating mode, since the heat exchange working fluid 200 in one of the first flow channel 201 and the second flow channel 203 exchanges heat with the battery cells 40, the volume of the heat exchange working fluid 200 is relatively small, which is beneficial to increasing the rate of temperature rise or temperature drop. In this way, the operating mode of the battery pack 101 can be selected according to the specific application scenario of the liquid cooling system 1, which is beneficial to reducing the energy consumption of the liquid cooling system 1.

[0096] In some embodiments of the present application, both the first multi-way valve 671 and the second multi-way valve 672 can be four-way valves. The first multi-way valve 671 and the second multi-way valve 672 both include a first valve port 6711, a second valve port 6712, a third valve port 6713, and a fourth valve port 6714. The first valve port 6711 of the first multi-way valve 671 is connected to the first liquid inlet 2011 of the first manifold 61, the second valve port 6712 of the first multi-way valve 671 is connected to the second liquid inlet 2033 of the third manifold 63, the third valve port 6713 of the first multi-way valve 671 is connected to the fourth valve port 6714 of the second multi-way valve 672, and the fourth valve port 6714 of the first multi-way valve 671 is connected to the heat exchanger 102 through a pipeline. The first valve port 6711 of the second multi-way valve 672 is connected to the second manifold 62, the second valve port 6712 of the second multi-way valve 672 is connected to the fourth manifold 64, the third valve port 6713 of the second multi-way valve 672 is connected to the pump 103, and the fourth valve port 6714 of the second multi-way valve 672 is connected to the third valve port 6713 of the first multi-way valve 671. It can be understood that the first multi-way valve 671 and the second multi-way valve 672 can also be other types of multi-way valves.

[0097] In some embodiments of the present application, when the battery pack 101 is in the first working mode, please refer to Figure 11 , the first valve port 6711 of the first multi-way valve 671, the second valve port 6712 of the first multi-way valve 671, the third valve port 6713 of the first multi-way valve 671, the fourth valve port 6714 of the first multi-way valve 671, the first valve port 6711 of the second multi-way valve 672, the second valve port 6712 of the second multi-way valve 672, the third valve port 6713 of the second multi-way valve 672, and the fourth valve port 6714 of the second multi-way valve 672 are all opened, that is, the four valve ports of the first multi-way valve 671 and the second multi-way valve 672 are all opened, the first manifold 61 and the second manifold 62 are both conducted, the third manifold 63 and the fourth manifold 64 are both conducted, and the heat transfer working medium 200 flows or circulates in both the first flow channel 201 and the second flow channel 203. The heat transfer working medium 200 in the first flow channel 201 and the second flow channel 203 exchanges heat with the battery cells 40. In this way, the volume of the area where the heat transfer working medium 200 flows in the battery pack 101 is relatively large, which is beneficial to increasing the heat exchange capacity of the battery pack 101.

[0098] In some embodiments of the present application, the second working mode includes a first sub-mode and a second sub-mode. When the battery pack 101 is in the first sub-mode, please refer to Figure 12, the first valve port 6711 of the first multi-way valve 671, the third valve port 6713 of the first multi-way valve 671, the first valve port 6711 of the second multi-way valve 672, and the third valve port 6713 of the second multi-way valve 672 are all opened, and the second valve port 6712 of the first multi-way valve 671, the third valve port 6713 of the first multi-way valve 671, the second valve port 6712 of the second multi-way valve 672, and the fourth valve port 6714 of the second multi-way valve 672 are all closed. In this way, the first valve port 6711 and the fourth valve port 6714 of the first multi-way valve 671 are connected, the first valve port 6711 and the third valve port 6713 of the second multi-way valve 672 are connected, and the third manifold 63 and the fourth manifold 64 are both closed, enabling the heat exchange working medium 200 to flow or circulate in the first manifold 61, the first flow channel 201, and the second manifold 62, and the heat exchange working medium 200 does not flow in the second flow channel 203.

[0099] Please refer to Figure 13 , when the battery pack 101 is in the second sub-mode, the second valve port 6712 of the first multi-way valve 671, the fourth valve port 6714 of the first multi-way valve 671, the second valve port 6712 of the second multi-way valve 672, and the third valve port 6713 of the second multi-way valve 672 are all opened, and the first valve port 6711 of the first multi-way valve 671, the third valve port 6713 of the first multi-way valve 671, the first valve port 6711 of the second multi-way valve 672, and the fourth valve port 6714 of the second multi-way valve 672 are all closed. In this way, the second valve port 6712 and the fourth valve port 6714 of the first multi-way valve 671 are connected, the second valve port 6712 and the third valve port 6713 of the second multi-way valve 672 are connected, and the first manifold 61 and the second manifold 62 are both closed, enabling the heat exchange working medium 200 to flow or circulate in the third manifold 63, the second flow channel 203, and the fourth manifold 64, and the heat exchange working medium 200 does not flow in the first flow channel 201.

[0100] The liquid cooling system 1 can have multiple working scenarios, such as a fast charging scenario, a low-temperature start-up scenario, and a discharging scenario. Different control strategies can be used to control devices such as the pump 103, the heat exchanger 102, the first multi-way valve 671, and the second multi-way valve 672 in the liquid cooling system 1, enabling the liquid cooling system 1 to work under different working scenarios. When the liquid cooling system 1 is in the fast charging scenario, it fast charges the battery pack 101. Since the battery pack 101 generates a large amount of heat during fast charging, the battery pack 101 is controlled to be in the first working mode, and the heat exchange working medium 200 flows in both the first flow channel 201 and the second flow channel 203, increasing the heat exchange area between the battery cells 40 and the heat exchange working medium 200, and improving the heat exchange efficiency and heat exchange capacity of the battery pack 101.

[0101] When the liquid cooling system 1 is in a low-temperature start-up scenario, for example, when the temperature of the battery pack 101 is lower than -15 °C, the heat exchanger 102 or the heater is controlled to heat the heat transfer medium 200, and the heat transfer medium 200 heats the battery cells 40. If the volume of the heat transfer medium 200 is too large, the temperature rise rate of the heat transfer medium 200 will be slow, and the low-temperature start-up time will be increased. In this case, the battery pack 101 can be selected to operate in the second working mode, that is, the heat transfer medium 200 circulates in one of the first flow channel 201 and the second flow channel 203. In this way, since the volume of the circulating heat transfer medium 200 is small, the temperature rise rate can be increased, which is beneficial to reducing the low-temperature start-up duration. Since the area of the first side 4262 is larger than the area of the bottom surface 424 of the battery cell, the second sub-mode of the second working mode can be selected to further reduce the volume of the heat transfer medium 200 and increase the temperature rise rate.

[0102] In some discharge scenarios of the present application, for example, in a low-heat discharge scenario where the heat generated by the discharging battery cells 40 per unit time does not exceed a preset value, or in a short-time discharge scenario where the discharge duration of the battery cells 40 does not exceed a preset duration, the heat generated by the battery pack 101 is not large. The battery pack 101 can be in the first working mode, and the heat exchanger 102 can not actively cool the heat transfer medium 200. The control pump 103 is controlled to drive the heat transfer medium 200 to circulate in the first flow channel 201 and the second flow channel 203. The battery cells 40 of the battery pack 101 are cooled by the circulation of the heat transfer medium 200 to save the active cooling energy consumption. The preset value and the preset duration can be set according to different characteristics of the battery cells 40.

[0103] In some embodiments of the present application, the first flow channel 201 and the second flow channel 203 can also be connected to each other to enable the heat transfer medium 200 to circulate between the first flow channel 201 and the second flow channel 203, that is, the heat transfer medium 200 forms an integrated flow in the battery pack 101. As Figure 14 shown, the battery pack 101 is also provided with a communication flow channel 207, and the communication flow channel 207 communicates the first flow channel 201 and the second flow channel 203. Among them, the second liquid outlet 2035 of the second flow channel 203 is communicated with the communication flow channel 207; after the heat transfer medium 200 passes through the second liquid inlet 2033, the second liquid outlet 2035, and the communication flow channel 207, it enters the first flow channel 201. It can be understood that the communication flow channel 207 can be a flow channel formed on the box body 20, and the communication flow channel 207 can also be arranged on a pipeline or a structural member connected between the first flow channel 201 and the second flow channel 203. The present application does not limit the way of realizing the connection between the first flow channel 201 and the second flow channel 203.

[0104] It can be understood that the present application does not limit the flow mode of the heat exchange working medium 200 in the battery pack 101. For example, in some possible implementation manners, the first liquid outlet 2013 of the first flow channel 201 is communicated with the communication flow channel; after the heat exchange working medium 200 passes through the first liquid inlet 2011, the first liquid outlet 2013, and the communication flow channel 207, it enters the second flow channel 203.

[0105] It should be understood that expressions such as "including" and "may include" that can be used in the present application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In the present application, terms such as "including" and / or "having" can be interpreted as indicating a specific characteristic, number, operation, constituent element, component, or a combination thereof, but cannot be interpreted as excluding the existence or possibility of addition of one or more other characteristics, numbers, operations, constituent elements, components, or a combination thereof.

[0106] In addition, in the present application, the expression "and / or" includes any and all combinations of the associated listed words. For example, the expression "A and / or B" can include A, can include B, or can include both A and B.

[0107] In the present application, expressions including ordinal numbers such as "first" and "second" can modify each element. However, such elements are not limited by the above expressions. For example, the above expressions do not limit the order and / or importance of the elements. The above expressions are only used to distinguish one element from other elements. For example, the first user equipment and the second user equipment indicate different user equipments, although both the first user equipment and the second user equipment are user equipments. Similarly, without departing from the scope of the present application, the first element can be referred to as the second element, and similarly, the second element can also be referred to as the first element.

[0108] When a component is referred to as being "connected" or "connected to" another component, it should be understood that: the component is not only directly connected to or connected to the other component, but there may also be another component between the component and the other component. On the other hand, when a component is referred to as being "directly connected" or "directly connected to" another component, it should be understood that there is no component between them.

[0109] As described above, the above are only specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed in the present application can easily think of changes or substitutions, which should all be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claimed rights.

Claims

1. A battery pack, characterized in that, It includes a box body and multiple battery cells. The multiple battery cells are accommodated in the box body or a sealed space is formed between the battery cells and the box body. Each battery cell includes a cell body and an electrical connection member provided on the cell body. A first flow channel is formed between two adjacent battery cells or between a battery cell and the inner wall of the box body. The first flow channel is used to accommodate a heat transfer working medium, and at least part of the cell body is immersed in the heat transfer working medium. The contact area between the electrical connection member and the heat transfer working medium is zero. The electrical connection member is a terminal post and / or a high-voltage conductive bar between the terminal posts.

2. The battery pack according to claim 1, characterized in that, The first flow channel includes a straight flow channel. The straight flow channel includes a first liquid inlet and a first liquid outlet. The straight flow channel extends in a first direction. The first liquid inlet of the straight flow channel is located at one end of the straight flow channel in the first direction for inputting the heat transfer working medium, and the first liquid outlet of the straight flow channel is located at the other end of the straight flow channel in the first direction for outputting the heat transfer working medium.

3. The battery pack according to claim 2, wherein, The number of the straight flow channels is at least two, and the at least two straight flow channels are arranged in a second direction perpendicular to the first direction.

4. The battery pack according to any one of claims 1-3, characterized in that, The first flow channel includes a curved flow channel. The curved flow channel includes a first liquid inlet and a first liquid outlet. The first liquid inlet of the curved flow channel is used for inputting the heat transfer working medium, and the first liquid outlet of the curved flow channel is used for outputting the heat transfer working medium.

5. The battery pack according to claim 4, characterized in that, The curved flow channel further includes a first part and a second part that are connected and communicate with each other. The first part and the second part are arranged in the second direction. The first liquid inlet of the curved flow channel is provided on the first part, and the first liquid outlet of the curved flow channel is provided on the second part.

6. The battery pack according to claim 5, characterized in that, The first liquid inlet of the curved flow channel is provided at the first end of the first part in the first direction. The second end of the first part in the first direction is connected to the first end of the second part in the first direction. The first liquid outlet of the curved flow channel is provided at the second end of the second part in the first direction. The first direction is perpendicular to the second direction.

7. The battery pack according to claim 6, wherein The curved flow channel further includes a third part. The first part, the third part, and the second part are arranged in sequence in the second direction. The first end of the third part in the first direction is connected to the second end of the first part, and the second end of the third part in the first direction is connected to the first end of the second part. The first end of the first part, the second end of the third part, and the first end of the second part are arranged in sequence in the second direction.

8. The battery pack according to any one of claims 2-7, characterized in that, The battery pack further includes a flow guiding strip fixed between two adjacent battery cells. The flow guiding strip, the battery cells, and the inner wall of the box body enclose the first flow channel.

9. The battery pack according to any one of claims 1-8, characterized in that, A second flow channel is provided on the inner wall of the box body. The second flow channel is used to accommodate the heat transfer working medium. The second flow channel includes an opening, a second liquid inlet, and a second liquid outlet that are connected and communicate with each other. The second liquid inlet is used for inputting the heat transfer working medium, and the second liquid outlet is used for outputting the heat transfer working medium. Each battery cell covers a corresponding opening.

10. The battery pack according to claim 9, wherein, The box body includes a main body and a plurality of support pads. The plurality of support pads are spaced apart and arranged on the inner wall of the main body. A second flow channel is formed between every two adjacent support pads. Each battery cell is connected to two adjacent support pads corresponding thereto.

11. The battery pack according to claim 9, wherein, The box body includes a main body and a partition member received in the main body. The partition member and the inner wall of the main body define a second flow channel and a receiving cavity which are separately arranged. The partition member is provided with a plurality of openings, and a plurality of battery cells are received in the receiving cavity.

12. The battery pack according to any one of claims 9-11, characterized in that, The second flow channel extends in a first direction. In the first direction, the length of the second flow channel is greater than the length of the battery cell, and a part of the opening of the second flow channel is exposed outside the plurality of battery cells.

13. The battery pack according to any one of claims 9-12, characterized in that, The box body is further provided with a communication flow channel which communicates the first flow channel and the second flow channel.

14. The battery pack according to any one of claims 9-11, characterized in that, The battery pack further includes a first current collector pipe, a second current collector pipe, a third current collector pipe, a fourth current collector pipe, a first multi-way valve and a second multi-way valve. The first current collector pipe, the first flow channel and the second current collector pipe are connected to each other. The third current collector pipe, the second flow channel and the fourth current collector pipe are connected to each other. The first multi-way valve is connected to the first current collector pipe and the third current collector pipe. The second multi-way valve is connected to the second current collector pipe and the fourth current collector pipe. The first multi-way valve and the second multi-way valve are connected to each other. The first multi-way valve and the second multi-way valve are used to control the on-off of the third current collector pipe, the fourth current collector pipe, the first current collector pipe and the second current collector pipe.

15. The battery pack according to claim 14, characterized in that, The battery pack includes a first working mode and a second working mode. By controlling the second multi-way valve and the first multi-way valve, the battery pack can be switched between the first working mode and the second working mode. When the battery pack is in the first working mode, the heat exchange working medium can flow in the first flow channel and the second flow channel. When the battery pack is in the second working mode, the heat exchange working medium can flow in one of the first flow channel and the second flow channel.

16. The battery pack according to claim 15, wherein, The first current collector pipe, the second current collector pipe, the third current collector pipe, the fourth current collector pipe, the first multi-way valve and the second multi-way valve are all located in the box body.

17. The battery pack according to any one of claims 1-16, characterized in that, The core body includes a battery cell top surface, a battery cell bottom surface and a battery cell side surface. The battery cell top surface and the battery cell bottom surface are oppositely arranged. The battery cell side surface is connected between the battery cell top surface and the battery cell bottom surface. The electrical connection member is arranged on the battery cell top surface. The battery cell side surface includes two first side surfaces and two second side surfaces. The two first side surfaces are opposite and parallel to each other. The two second side surfaces are opposite and parallel to each other. The area of the first side surface is larger than the area of the second side surface. The first side surfaces of the plurality of battery cells are arranged. A first flow channel is formed between the first side surfaces of two adjacent battery cells.

18. A liquid cooling system, characterized in that, It includes a heat exchanger, a pump and the battery pack according to any one of claims 1-17. The heat exchanger, the pump and the first flow channel of the battery pack are connected through pipelines.

19. A vehicle, characterized in that, It includes a vehicle body and the liquid cooling system according to claim 18. The liquid cooling system is arranged on the vehicle body.

20. An energy storage system, characterized in that, Comprising the liquid cooling system according to claim 18.

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