Liquid cold plate, battery pack, thermal management system, and vehicle

Abstract

The application relates to a liquid cooling plate, a battery pack, a thermal management system and a vehicle. The battery pack comprises a water inlet, a water outlet, a plurality of liquid cooling plates and a plurality of battery cells. In a first direction of the battery pack, the two ends of the liquid cooling plate are provided with a flow channel inlet and a flow channel outlet. The flow channel inlet is communicated with the water inlet, and the flow channel outlet is communicated with the water outlet. In a second direction of the battery pack, the plurality of liquid cooling plates are arranged at intervals. The flow channel inlet and the flow channel outlet of one of the two adjacent liquid cooling plates are communicated with the flow channel inlet and the flow channel outlet of the other liquid cooling plate. The first direction is the width direction of the battery pack. The second direction is the length direction of the battery pack. The battery cells are arranged between the two adjacent liquid cooling plates, and the two side surfaces of the battery cells in the second direction are respectively in contact with the adjacent liquid cooling plates. In the second direction and in the direction away from the water inlet, the contact thermal resistances of the at least two liquid cooling plates are sequentially reduced. The structure is easy to manufacture and realize. The heat exchange capacity difference between the liquid cooling plates can be reduced, and the temperature difference between the battery cells can be reduced.

Description

Technical Field

[0001] This application relates to the field of vehicle technology, specifically to a liquid cooling plate, a battery pack, a thermal management system, and a vehicle. Background Technology

[0002] With global focus on environmental protection and carbon emissions, the demand for electric vehicles is increasing year by year. Electric vehicles include batteries; excessively high or low operating temperatures can affect battery safety and lifespan. Uneven temperature distribution can lead to large temperature differences in some battery cells, causing localized performance imbalances and impairing overall battery performance. Therefore, balancing rapid heat exchange with uniform temperature performance is crucial. Liquid cooling plates are important components in current battery thermal management systems, enabling direct heat transfer through contact with the battery surface. Among them, double-sided liquid cooling plates, which cover a larger surface area of ​​the battery and offer faster heat transfer efficiency, are widely used in power batteries.

[0003] Existing batteries typically include multiple double-sided liquid cooling plates, which are spaced apart and connected by pipes. However, due to differences in the flow resistance of the cooling medium at different locations within the pipes, the flow rate of the cooling medium in the liquid cooling plates at different locations within the battery also varies. This results in different heat exchange capacities for the liquid cooling plates at different locations within the battery, which can easily lead to significant temperature differences among the cells at different locations within the battery. Summary of the Invention

[0004] In view of this, this application provides a liquid cooling plate, a battery pack, a thermal management system, and a vehicle to reduce the difference in heat exchange capacity between liquid cooling plates at different locations within the battery pack and reduce the temperature difference between battery cells within the battery pack.

[0005] The first aspect of this application provides a battery pack, which includes a water inlet and a water outlet, and further includes multiple liquid cooling plates and multiple battery cells. Along a first direction of the battery pack, each liquid cooling plate has a flow channel inlet and a flow channel outlet at both ends, the flow channel inlet communicating with the water inlet and the flow channel outlet communicating with the water outlet. Along a second direction of the battery pack, the multiple liquid cooling plates are spaced apart, and the flow channel inlets of two adjacent liquid cooling plates are connected, as are the flow channel outlets of two adjacent liquid cooling plates. The first direction is the width direction of the battery pack; the second direction is the length direction of the battery pack. A battery cell is disposed between two adjacent liquid cooling plates, and the battery cell contacts two adjacent liquid cooling plates on its two sides along the second direction. Along the second direction, and in the direction away from the water inlet, the contact thermal resistance of at least two liquid cooling plates decreases sequentially.

[0006] Along the second direction, and along the direction away from the water inlet, by successively reducing the contact thermal resistance between at least two liquid cooling plates and the corresponding cells, the heat exchange efficiency of at least two liquid cooling plates can be successively increased, that is, the heat exchange capacity can be successively increased. This can reduce the heat exchange capacity of the liquid cooling plates in the area near the water inlet in the battery pack, and / or successively increase the heat exchange capacity of the liquid cooling plates in the area away from the water inlet in the battery pack. This reduces the difference in heat exchange capacity of liquid cooling plates at different locations in the battery pack, improves the uniformity of heat exchange capacity of each liquid cooling plate in the battery pack, further reduces the temperature difference between cells in the battery pack, and makes the temperature field distribution of the battery pack more uniform. In terms of battery pack heating, improving the heat exchange capacity of the liquid cooling plate furthest from the water inlet makes it easier to raise the cell temperature at that location. This reduces temperature differences between cells and prevents localized overcooling, thereby improving the utilization of charging current and enhancing the charging efficiency of the battery pack. Conversely, in terms of battery pack cooling, improving the heat exchange capacity of the liquid cooling plate furthest from the water inlet makes it easier to lower the cell temperature at that location. This reduces temperature differences between cells and prevents localized overheating, thus slowing down battery aging and extending the battery pack's lifespan. Furthermore, reduced temperature differences between cells within the battery pack ensure that the cells operate at a more uniform level, improving the overall performance of the battery pack. Furthermore, compared to reducing the flow rate difference of the cooling medium in each liquid cooling plate by changing the flow channels and the arrangement of the flow channel openings, the embodiments of this application adjust the heat exchange capacity of each liquid cooling plate by adjusting the contact thermal resistance between the liquid cooling plates at different positions in the battery pack and the corresponding cells. This enables the design of the flow channels and flow channel openings in each liquid cooling plate to be unified, thereby reducing manufacturing difficulty and making it easier to assemble the liquid cooling plates in a unified manner and to prepare and implement them.

[0007] In one possible design, the liquid cooling plate includes a plate body and a thermally conductive medium layer disposed on the surface of the plate body; the thickness of the thermally conductive medium layer of at least two of the liquid cooling plates decreases sequentially.

[0008] Since the thickness of the thermally conductive medium layer is directly proportional to the contact thermal resistance, the greater the thickness of the thermally conductive medium layer, the greater the contact thermal resistance. Therefore, when the thickness of the thermally conductive medium layer corresponding to at least two liquid cooling plates decreases sequentially along the second direction and in the direction away from the water inlet, the contact thermal resistance between the two liquid cooling plates and the corresponding battery cells can be reduced sequentially, thereby increasing the heat exchange capacity of at least two liquid cooling plates sequentially.

[0009] In one possible design, the liquid cooling plate includes a plate body and a thermally conductive medium layer, the thermally conductive medium layer being disposed on the surface of the plate body; the thermal conductivity of the thermally conductive medium layer corresponding to at least two of the liquid cooling plates increases sequentially.

[0010] Since the thermal conductivity of the heat-conducting medium layer is inversely proportional to the contact thermal resistance, the greater the thermal conductivity of the heat-conducting medium layer, the smaller the contact thermal resistance. Therefore, when the thermal conductivity of the heat-conducting medium layer corresponding to at least two liquid cooling plates increases sequentially along the second direction and in the direction away from the water inlet, the contact thermal resistance between the two liquid cooling plates and the corresponding battery cells can be reduced sequentially, thereby increasing the heat exchange capacity of at least two liquid cooling plates sequentially.

[0011] In one possible design, the contact area between at least two of the liquid cooling plates and the corresponding battery cells increases sequentially.

[0012] Since the contact area is inversely proportional to the contact thermal resistance, the larger the contact area, the smaller the contact thermal resistance. Therefore, when the contact area between multiple liquid cooling plates and the corresponding battery cells increases sequentially along the second direction and in the direction away from the water inlet, the contact thermal resistance between the two liquid cooling plates and the corresponding battery cells can be reduced sequentially, thereby increasing the heat exchange capacity of at least two liquid cooling plates sequentially.

[0013] In one possible design, along the second direction, the ratio of the maximum contact thermal resistance to the minimum contact thermal resistance of the liquid cooling plates at both ends of the battery pack is between 1 and 3.

[0014] When the ratio of the maximum contact thermal resistance to the minimum contact thermal resistance between the liquid cooling plates at both ends of the battery pack and the corresponding cells is between 1 and 3 along the second direction, it can ensure that the liquid cooling plates at each position in the battery pack have good heat exchange capacity, and at the same time, it can play a good role in balancing the heat exchange capacity of the liquid cooling plates at different positions in the battery pack, further reducing the temperature difference between the cells in the battery pack.

[0015] In one possible design, the liquid cooling plate includes multiple contact areas, and the contact thermal resistance of at least two of the contact areas decreases sequentially along the first direction and along the direction away from the flow channel inlet.

[0016] Since contact thermal resistance is inversely proportional to heat transfer efficiency, the higher the contact thermal resistance, the lower the heat transfer efficiency. Therefore, when the contact thermal resistance between at least two contact areas and their corresponding cells decreases sequentially along the first direction and in the direction away from the flow channel inlet, the heat transfer efficiency of at least two contact areas increases sequentially, that is, the heat transfer capacity increases sequentially. This reduces the heat transfer capacity of the contact area near the flow channel inlet on the liquid cooling plate, while simultaneously increasing the heat transfer capacity of the contact area away from the flow channel inlet on the liquid cooling plate. This reduces the difference in heat transfer capacity among the various contact areas of the liquid cooling plate, improves the uniformity of heat transfer capacity among the various contact areas of the liquid cooling plate, and improves the uniformity of the temperature change rate between each heat transfer area and the corresponding contact cell. This reduces the temperature difference between cells, improves the temperature uniformity of the liquid cooling plate, and makes the temperature field distribution of the battery pack more uniform. In the heating phase of the battery pack, improving the heat transfer capacity of the contact area far from the flow channel inlet makes it easier to raise the cell temperature there. This reduces temperature differences between cells and prevents localized overcooling, thereby improving the utilization of charging current and enhancing the charging efficiency of the battery pack. Conversely, in the cooling phase, improving the heat transfer capacity of the contact area far from the flow channel inlet makes it easier to lower the cell temperature there. This reduces temperature differences between cells and prevents localized overheating, thus slowing down battery aging and extending the battery pack's lifespan. Furthermore, reduced temperature differences between cells within the battery pack make it easier for cells to operate at similar operating levels, further improving the overall performance of the battery pack. Moreover, in this embodiment, the heat transfer capacity of each contact area of ​​the liquid cooling plate is adjusted only by regulating the contact thermal resistance between the contact area and the corresponding cell, without needing to separately adjust the temperature and flow rate of the cooling medium within the liquid cooling plate. This further improves the thermal management efficiency of the battery pack, saves energy, and is easy to manufacture and implement.

[0017] In one possible design, the liquid cooling plate includes a plate body and a thermally conductive medium layer disposed on the surface of the plate body, wherein the thickness of the thermally conductive medium layer in at least two of the contact areas decreases sequentially.

[0018] Since the thickness of the thermally conductive medium layer is directly proportional to the contact thermal resistance, the greater the thickness of the thermally conductive medium layer, the greater the contact thermal resistance. Therefore, when the thickness of the thermally conductive medium layer corresponding to at least two contact areas decreases sequentially along the first direction and in the direction away from the flow channel inlet, the contact thermal resistance between at least two contact areas and the corresponding battery cells can be reduced sequentially, thereby increasing the heat exchange capacity of at least two contact areas sequentially.

[0019] In one possible design, the liquid cooling plate includes a plate body and a thermally conductive medium layer disposed on the surface of the plate body; the thermal conductivity of the thermally conductive medium layer in at least two of the contact areas increases sequentially.

[0020] Since the thermal conductivity of the thermally conductive medium layer is inversely proportional to the contact thermal resistance, the greater the thermal conductivity of the thermally conductive medium layer, the smaller the contact thermal resistance. Therefore, when the thermal conductivity of the thermally conductive medium layer corresponding to at least two contact areas increases sequentially along the first direction and in the direction away from the flow channel inlet, the contact thermal resistance between at least two contact areas and the corresponding battery cells can be reduced sequentially, thereby increasing the heat exchange capacity of at least two contact areas sequentially.

[0021] In one possible design, the contact area of ​​at least two of the contact areas with the corresponding battery cell increases sequentially.

[0022] Since the contact area is inversely proportional to the contact thermal resistance, the larger the contact area, the smaller the contact thermal resistance. Therefore, when the contact area between at least two contact areas and the corresponding battery cell increases sequentially along the first direction and in the direction away from the flow channel inlet, the contact thermal resistance between at least two contact areas and the corresponding battery cell can be reduced sequentially, thereby increasing the heat exchange capacity of at least two contact areas sequentially.

[0023] In one possible design, along the first direction, the ratio of the maximum contact thermal resistance to the minimum contact thermal resistance in the contact areas at both ends of the liquid cooling plate is between 1 and 3.

[0024] When the ratio of the maximum to the minimum contact thermal resistance between the contact areas at both ends of the liquid cooling plate and the corresponding battery cell is between 1 and 3 along the first direction, it can ensure that the liquid cooling plate has good heat exchange capacity while playing a good role in balancing the heat exchange capacity of each contact area on the liquid cooling plate, thereby improving the temperature uniformity of the liquid cooling plate.

[0025] In one possible design, the thickness of the thermally conductive medium layer is less than or equal to 10 mm.

[0026] If the thermally conductive medium layer is too thick, for example, greater than 10mm, the contact thermal resistance of the liquid cooling plate will be too high, resulting in weak heat exchange capacity. This prevents timely heat exchange with the battery cells in contact with the liquid cooling plate, reducing the overall performance of the battery pack, decreasing its thermal management efficiency, increasing energy consumption, hindering charging efficiency, and shortening its lifespan. Therefore, a thermally conductive medium layer thickness of less than or equal to 10mm ensures a moderate contact thermal resistance for the liquid cooling plate, meeting various heat exchange requirements, increasing design freedom for the battery pack, guaranteeing overall performance, improving thermal management efficiency, saving energy, and also enhancing charging efficiency and lifespan.

[0027] In one possible design, the liquid cooling plate is provided with a flow channel, and along the first direction, the two ends of the flow channel are provided with the flow channel inlet and the flow channel outlet. The flow channel is one or a combination of a serpentine flow channel or a straight flow channel.

[0028] The serpentine flow channel increases the flow path length of the cooling medium within the liquid cooling plate, thereby increasing the contact time between the cooling medium and the liquid cooling plate and improving the heat exchange efficiency. Furthermore, the tortuous design of the serpentine flow channel generates disturbances in the cooling medium as it flows, contributing to improved heat exchange uniformity. Compared to serpentine flow channels, the resistance to cooling medium flow in straight flow channels is lower, enabling heat transfer to be completed in a relatively shorter time. By rationally designing serpentine and / or straight flow channels within the liquid cooling plate, the heat exchange capacity of the liquid cooling plate can be effectively optimized, allowing it to handle heat sources with different heat flux densities. It also helps to even out the temperature across different areas of the liquid cooling plate within a limited space, thus improving the plate's temperature uniformity.

[0029] A second aspect of this application provides a liquid cooling plate, wherein the liquid cooling plate has a flow channel inlet and a flow channel outlet at both ends, and the side surface of the liquid cooling plate includes at least two contact areas, wherein the contact thermal resistance of the at least two contact areas decreases sequentially along the direction away from the flow channel inlet.

[0030] Since contact thermal resistance is inversely proportional to heat transfer efficiency, the higher the contact thermal resistance, the lower the heat transfer efficiency. Therefore, when the contact thermal resistance between at least two contact areas and their corresponding cells decreases sequentially along the first direction and in the direction away from the flow channel inlet, the heat transfer efficiency of at least two contact areas increases sequentially, that is, the heat transfer capacity increases sequentially. This reduces the heat transfer capacity of the contact area near the flow channel inlet on the liquid cooling plate, while simultaneously increasing the heat transfer capacity of the contact area away from the flow channel inlet on the liquid cooling plate. This reduces the difference in heat transfer capacity among the various contact areas of the liquid cooling plate, improves the uniformity of heat transfer capacity among the various contact areas of the liquid cooling plate, and improves the uniformity of the temperature change rate between each heat transfer area and the corresponding contact cell. This reduces the temperature difference between cells, improves the temperature uniformity of the liquid cooling plate, and makes the temperature field distribution of the battery pack more uniform. In the heating phase of the battery pack, improving the heat transfer capacity of the contact area far from the flow channel inlet makes it easier to raise the cell temperature there. This reduces temperature differences between cells and prevents localized overcooling, thereby improving the utilization of charging current and enhancing the charging efficiency of the battery pack. Conversely, in the cooling phase, improving the heat transfer capacity of the contact area far from the flow channel inlet makes it easier to lower the cell temperature there. This reduces temperature differences between cells and prevents localized overheating, thus slowing down battery aging and extending the battery pack's lifespan. Furthermore, reduced temperature differences between cells within the battery pack make it easier for cells to operate at similar operating levels, improving the overall performance of the battery pack. Moreover, in this embodiment, the heat transfer capacity of each contact area of ​​the liquid cooling plate is adjusted only by regulating the contact thermal resistance between the contact area and the corresponding cell, eliminating the need to adjust the temperature and flow rate of the cooling medium within the liquid cooling plate. This further improves the thermal management efficiency of the battery pack, saves energy, and is easy to manufacture and implement.

[0031] A third aspect of this application provides a battery pack comprising a plurality of liquid cooling plates as provided in the second aspect and a plurality of battery cells. Along a second direction of the battery pack, the plurality of liquid cooling plates are spaced apart, and a battery cell is disposed between two adjacent liquid cooling plates. The battery cell has two sides along the second direction that respectively contact contact areas on adjacent liquid cooling plates. Since liquid cooling plates have the aforementioned technical effects, the battery pack including liquid cooling plates should also possess corresponding technical effects, which will not be elaborated further here.

[0032] A fourth aspect of this application provides a thermal management system, which includes the battery pack described in any of the above embodiments. Since the battery pack has the aforementioned technical effects, the thermal management system including the battery pack should also possess corresponding technical effects, which will not be elaborated further here.

[0033] A fifth aspect of this application provides a means of transportation, characterized in that the means of transportation includes the aforementioned thermal management system. Since the thermal management system has the aforementioned technical effects, the means of transportation including the thermal management system should also possess corresponding technical effects, which will not be elaborated further here.

[0034] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this application. Attached Figure Description

[0035] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 A schematic diagram of the structure of the thermal management system provided in an embodiment of this application in a specific embodiment;

[0037] Figure 2 A schematic diagram of the structure of the thermal management system provided in this application embodiment in another specific embodiment;

[0038] Figure 3 This is a schematic diagram of the structure of a battery pack in the related technology;

[0039] Figure 4 A schematic diagram of the structure of the battery pack provided in an embodiment of this application in a specific embodiment;

[0040] Figure 5 A partial structural schematic diagram of a battery pack provided in an embodiment of this application in one specific embodiment;

[0041] Figure 6 An exploded view of a battery pack provided in an embodiment of this application in one specific embodiment;

[0042] Figure 7 A schematic diagram of the structure of the liquid cooling plate provided in an embodiment of this application in a specific embodiment;

[0043] Figure 8 An exploded view of the battery pack provided in one embodiment of this application in another specific embodiment;

[0044] Figure 9 A cross-sectional view of a liquid cooling plate provided in an embodiment of this application in a specific embodiment;

[0045] Figure 10 A partially exploded view of the battery pack provided in an embodiment of this application in one specific embodiment;

[0046] Figure 11 This is a schematic diagram of the structure of the liquid cooling plate provided in an embodiment of this application in another specific embodiment.

[0047] Figure label:

[0048] 10'-battery;

[0049] 1'-Liquid cooling plate;

[0050] 2'-cell;

[0051] 3'-pipe;

[0052] 4'-water inlet;

[0053] 5' - Outlet;

[0054] 100-Thermal Management System;

[0055] 10-Battery Pack;

[0056] 1-Liquid cooling plate;

[0057] 1a-First liquid cooling plate; 1b-Second liquid cooling plate; 1c-Third liquid cooling plate; 11-Flow channel inlet; 12-Flow channel outlet; 13-Flow channel; 13a-First flow channel; 13b-Second flow channel; 13c-Third flow channel; 13d-Fourth flow channel; 14a-First contact area; 14b-Second contact area; 14c-Third contact area; 15-Plate body; 16-Heat-conducting medium layer; 16a-First heat-conducting medium layer; 16b-Second heat-conducting medium layer; 16c-Third heat-conducting medium layer;

[0058] 2-Battery cell;

[0059] 3-Pipeline;

[0060] 4-Water inlet;

[0061] 5-Outlet;

[0062] 6-Current collector;

[0063] 20-Refrigerant circuit;

[0064] 201-Refrigerant box; 202-Air conditioning unit; 203-First driving component; 204-Heat exchanger; 205-Second thermistor;

[0065] 30 - Cooling water circuit;

[0066] 301 - Water tank; 302 - First thermistor; 303 - Second driving component;

[0067] X - First direction;

[0068] Y - Second direction;

[0069] Z - Third-party orientation.

[0070] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. Detailed Implementation

[0071] To better understand the technical solution of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0072] In the description of this application, unless otherwise expressly specified and limited, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; unless otherwise specified or explained, the term "multiple" refers to two or more; the terms "connected," "fixed," etc., should be interpreted broadly. For example, "connected" can be a fixed connection, a detachable connection, an integral connection, or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0073] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0074] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0075] With global focus on environmental protection and carbon emissions, the demand for electric vehicles (EVs) is rising year by year. EVs include batteries, and to make EVs more attractive, fast charging technology has become a key development direction. Fast charging can not only significantly shorten charging time and improve ease of use, but also effectively address users' "range anxiety."

[0076] The demand for fast charging technology has been driven by advancements in lithium-ion battery technology and the widespread availability of public charging facilities and equipment. For example, a lithium-ion battery will be used as an example for illustration.

[0077] Fast charging generates a significant amount of heat inside the battery. Increased chemical reactions and current transfer within the battery produce additional heat. Without effective temperature control, the battery temperature can become excessively high, accelerating the instability of internal chemical reactions, leading to faster battery aging, and consequently affecting its cycle life and performance. Even worse, overheating can cause gas production inside the battery, damage to the separator, and may even trigger thermal runaway, short circuits, or fires.

[0078] Low-temperature charging can also lead to problems such as low efficiency and lithium plating. In low-temperature environments, the chemical reaction rate of lithium-ion batteries slows down, resulting in increased internal resistance, restricted ion migration, and inability to fully utilize the charging current, thus reducing charging efficiency. Simultaneously, during low-temperature charging, lithium ions may not be uniformly embedded in the electrodes, causing lithium metal to deposit on the negative electrode surface. This can lead to battery capacity degradation, increase the risk of internal short circuits, and in severe cases, potentially cause thermal runaway or fire.

[0079] Therefore, excessively high or low operating temperatures can affect battery safety and lifespan. Uneven temperature distribution can lead to large temperature differences in some battery cells, causing localized performance imbalances and impairing overall battery performance. Thus, balancing rapid heat exchange with uniform temperature distribution is crucial. Liquid cooling plates are important components in current battery thermal management systems, directly contacting the battery surface for heat transfer. Double-sided liquid cooling plates, in particular, are widely used in power batteries due to their ability to cover a larger battery surface area and achieve faster heat transfer efficiency.

[0080] This application provides a thermal management system including a battery pack with a liquid cooling plate, which can be applied to vehicles. This application does not impose any special limitations on the specific form of the vehicle described above; for ease of explanation, the following description uses an automobile as an example.

[0081] Figure 1 A schematic diagram of the structure of the thermal management system provided in an embodiment of this application is shown below. Figure 1 As shown, the thermal management system 100 includes a refrigerant circuit 20 and a cooling water circuit 30.

[0082] like Figure 1 As shown, the refrigerant circuit 20 can be formed by connecting components such as refrigerant box 201, air conditioning unit 202, first driving component 203 and heat exchanger 204 through refrigerant pipes. The first driving component 203 is used to drive the refrigerant in the refrigerant circuit to circulate in one direction.

[0083] The first driving component 203 can be a compressor or other driving component, and the air conditioning unit 202 can include a condenser, expansion valve, heat exchanger, throttling device, evaporator, etc., which can be set according to actual needs and are not limited here. In addition, the refrigerant can be carbon dioxide (CO2), but other substances such as propane can also be used, which can be set according to actual needs and are not limited here.

[0084] like Figure 1 As shown, the cooling water circuit 30 can be composed of a water tank 301, a second drive unit 303, and a battery pack 10 connected by a water pipe. The second drive unit 303 is used to drive the coolant in the cooling water circuit to circulate in one direction.

[0085] The second driving component 303 can be a water pump or other driving component. Additionally, to improve the heating effect in the cooling water circuit, a first thermistor 302 can be installed in the cooling water circuit 30. Specifically, the first thermistor 302 can be a positive temperature coefficient thermistor (PTC), etc., and the specific type can be selected according to actual needs without limitation. Furthermore, the coolant can be water, ethylene glycol, or a mixture of water and ethylene glycol, etc., and the specific type can be selected according to actual needs without limitation.

[0086] like Figure 1 As shown, the cooling water circuit 30 can be connected to the heat exchanger 204 so that the coolant in the cooling water circuit 30 can exchange heat with the refrigerant in the refrigerant circuit 20 in the heat exchanger 204, and then flow into the liquid cooling plate of the battery pack 10 to exchange heat with the battery cells, so as to save energy consumption.

[0087] Figure 2 A schematic diagram of the structure of the thermal management system provided in this application embodiment in another specific embodiment is shown below. Figure 2 As shown, the thermal management system 100 includes a refrigerant circuit 20. The refrigerant circuit 20 is formed by connecting components such as a refrigerant tank 201, an air conditioning unit 202, a first driving element 203, a heat exchanger 204, and a battery pack 10 via refrigerant pipes. The first driving element 203 drives the refrigerant in the circuit to circulate in one direction, allowing the refrigerant to directly flow into the liquid cooling plate of the battery 10 and contact the cell surface for heat exchange. This thermal management system 100 has a simple structure, reducing its complexity. Furthermore, because the specific heat capacity of the refrigerant is much smaller than that of the coolant, it is easier for the refrigerant to heat up or cool down quickly. Therefore, as... Figure 2 In the thermal management system 100 shown, the heat transfer efficiency between the liquid cooling plate with a cooling medium flowing in the battery pack 10 and the surface of the battery cell is higher, making it easier to quickly heat up or cool down the battery cell.

[0088] The first driving component 203 can be a compressor or other driving component, and the air conditioning unit 202 can include a condenser, expansion valve, heat exchanger, throttling device, evaporator, etc., which can be configured according to actual needs and are not limited here. Additionally, the refrigerant can be carbon dioxide (CO2). 2) Of course, the refrigerant can also be other substances, such as propane, etc., and the specific setting can be made according to actual needs, without any restrictions here. In addition, in order to improve the heating effect in the cooling water circuit, a second thermistor 205 can also be set in the refrigerant circuit 20. Specifically, the second thermistor 205 can be a positive temperature coefficient thermistor (PTC), etc., and the specific setting can be made according to actual needs, without any restrictions here.

[0089] Of course, the battery pack 10 can also be used in other thermal management systems. This application does not impose any special restrictions on the specific form of the thermal management system.

[0090] Please refer to Figure 3 , Figure 3 This is a schematic diagram of the structure of a battery pack in the related technology.

[0091] like Figure 3 As shown, the battery 10' includes multiple liquid cooling plates 1' and multiple battery cells 2'. The multiple liquid cooling plates 1' are spaced apart along the second direction Y and connected by a pipe 3'. At least some of the battery cells 2' are disposed between two adjacent liquid cooling plates 1'. The cooling medium can enter the pipe 3' through the inlet 4', and at least some of the cooling medium flows along the second direction Y in the pipe 3' and flows sequentially into the liquid cooling plates 1' distributed along the second direction Y, so that the multiple liquid cooling plates 1' can exchange heat with the battery cells 2' they are in contact with. Finally, the cooling medium can flow out through the outlet 5'. However, due to the difference in flow resistance of the cooling medium at different positions of the pipe 3', the flow rate of the cooling medium in the liquid cooling plates 1' at different positions in the battery 10' is also different, resulting in different heat exchange capabilities of the liquid cooling plates 1' at different positions in the battery 10', which can easily cause large temperature differences in the battery cells 2' at different positions in the battery 10'.

[0092] For example, the cooling medium can be water, ethylene glycol, or a mixture of water and ethylene glycol to reduce costs. Simultaneously, due to the high specific heat capacity of the coolant, the temperature change rate is slow during continuous heat exchange within the liquid cooling plate 1', resulting in smaller temperature differences between different areas of the liquid cooling plate 1' and improving the temperature uniformity of the liquid cooling plate 1'. For example, the cooling medium can also be carbon dioxide, propane, or other cold media. Because cold media have lower specific heat capacities, they are easier to heat up or cool down quickly. Therefore, the heat transfer efficiency between the liquid cooling plate 1' with the cold media flowing in the battery 10' and the surface of the cell 2' is higher, making it easier to achieve rapid heating or cooling of the cell 2'. However, the rapid temperature change rate during continuous heat exchange within the liquid cooling plate 1' can lead to significant temperature differences between different areas of the liquid cooling plate 1', potentially causing large temperature differences between different locations of the cell 2' within the battery 10'.

[0093] like Figure 3 As shown, when the cooling medium enters the pipe 3' through the inlet 4', due to its initial high or low temperature and high flow rate, the flow rate of the cooling medium into the liquid-cooled plate 1 near the inlet 4' is large, resulting in strong heat exchange capacity. The temperature change rate of the battery cell 2' in contact with the liquid-cooled plate 1' in this area is also rapid. However, as the cooling medium continues to flow into the liquid-cooled plate 1' further away from the inlet 4', the flow resistance in the pipe 3' gradually increases, and the flow rate of the cooling medium gradually decreases. This leads to a decrease in the flow rate of the cooling medium into the liquid-cooled plate 1' further away from the inlet 4', weakening the heat exchange capacity. Consequently, the temperature change rate of the battery cell 2 in contact with the liquid-cooled plate 1 further away from the inlet 4' decreases, resulting in slower temperature changes. Figure 3 In the specific embodiment shown, the battery 10' with 28 rows of cells 2' and 29 rows of liquid cooling plates 1' exhibits a flow rate difference of up to 20% within the liquid cooling plates 1' due to variations in the flow resistance of the liquid within the pipe 3' at different locations. When the water pump is at full load, this flow rate difference further increases, resulting in a maximum temperature difference of more than 10°C between the cells 2' at different locations within the battery 10'. This significant temperature difference affects the charging efficiency and lifespan of the battery 10'. Furthermore, if the temperature difference between the cells 2' within the battery 10' is too large during charging, it can easily lead to overheating or undercooling of certain cells 2', causing cells 2' at different locations within the battery 10' to operate in different states. This results in unbalanced battery performance, ultimately affecting the overall performance and safety of the battery 10'.

[0094] In view of this, this application provides a battery pack that can be applied to the above-mentioned thermal management system to reduce the difference in heat exchange capacity between liquid cooling plates at different locations within the battery pack and reduce the temperature difference between cells within the battery pack.

[0095] Please refer to Figure 4 and Figure 5 , Figure 4 This is a schematic diagram of the structure of the battery pack provided in one specific embodiment of the present application. Figure 5 This application provides a partial structural diagram of a battery pack in one specific embodiment. Figure 5 Pipe 3 is not shown. For ease of understanding, the width direction of the battery pack 10 is defined as the first direction X, the length direction of the battery pack 10 is defined as the second direction Y, and the height direction of the battery pack is defined as the third direction Z.

[0096] like Figure 4 As shown, the battery pack 10 includes multiple liquid cooling plates 1 and multiple battery cells 2. Along the second direction Y of the battery pack 10, the multiple liquid cooling plates 1 are spaced apart, and a battery cell 2 is disposed between two adjacent liquid cooling plates 1. The two sides of the battery cell 2 along the second direction Y are in contact with the adjacent liquid cooling plates 1, so that the liquid cooling plates 1 can exchange heat on both sides of each battery cell 2, thereby heating or cooling the battery cell 2.

[0097] like Figure 4 As shown, the battery pack 10 includes a water inlet 4 and a water outlet 5. The water inlet 4 and water outlet 5 can be located at the same end of the battery pack 10 along the second direction Y, facilitating the parallel connection of multiple liquid cooling plates 1, simplifying assembly, and simplifying maintenance. Furthermore, having the water inlet 4 and water outlet 5 at the same end of the battery pack 10 allows for single-sided sealing, simplifying sealing requirements and reducing costs. Of course, in some other embodiments, the water inlet 4 and water outlet 5 can also be arranged in other ways, such as at both ends of the battery pack 10 along the second direction Y, to increase the design freedom of the battery pack 10 and adapt to different layout environments. The specific arrangement can be determined according to actual needs and is not limited here.

[0098] like Figure 5 As shown, along the first direction X of the battery pack 10, the liquid cooling plate 1 has a flow channel inlet 11 and a flow channel outlet 12 at both ends. The cooling medium can flow into the liquid cooling plate 1 through the flow channel inlet 11 and flow out through the flow channel outlet 12. The flow channel inlets 11 of two adjacent liquid cooling plates 1 are connected, and the flow channel outlets 12 of two adjacent liquid cooling plates 1 are connected. That is, the flow channel inlet 11 and flow channel outlet 12 of one liquid cooling plate 1 are correspondingly connected to the flow channel inlet 11 and flow channel outlet 12 of the other liquid cooling plate, so that multiple liquid cooling plates 1 are connected. Please also refer to Figure 4The inlets 11 of the multiple liquid cooling plates 1 can be connected to the inlets 4 via pipes 3, and the outlets 12 of the multiple liquid cooling plates 1 can be connected to the outlets 5 via another pipe 3, thereby further reducing the structural complexity of the battery pack 10. Furthermore, along the first direction X, both ends of the liquid cooling plates 1 can be connected to a collector 6, allowing the pipes 3 to be connected to the liquid cooling plates 1 via the collector 6, facilitating the assembly of the pipes 3 and simplifying maintenance.

[0099] The cooling medium can enter the pipe 3 through the inlet 4, and at least part of the cooling medium flows in the pipe 3 along the second direction Y and flows into the liquid cooling plates 1 distributed along the second direction Y in sequence, so that the multiple liquid cooling plates 1 can exchange heat with the battery cells 2 in contact with them. Finally, the cooling medium can flow out through the outlet 5.

[0100] Because the flow resistance of the cooling medium varies at different locations in pipe 3, the flow rate of the cooling medium in the liquid cooling plate 1 at different locations also varies. This results in different heat exchange capacities of the liquid cooling plate 1 at different locations within the battery pack 10. Specifically, along the second direction Y, and in the direction away from the inlet 4, the heat exchange capacity of multiple liquid cooling plates 1 gradually decreases. If the design of multiple liquid cooling plates within the battery pack adopts a uniform contact thermal resistance, i.e., the contact thermal resistance of multiple liquid cooling plates is the same, then the heat exchange capacity of the liquid cooling plates in areas with higher or lower heat exchange capacity due to flow differences within the battery pack cannot be adjusted. This will still easily increase the temperature difference between the cells within the battery pack, thereby affecting the charging effect and service life of the battery pack. It will also easily lead to local overheating or undercooling of cells within the battery pack, causing cells at different locations within the battery pack to be in different working states, resulting in unbalanced battery performance and thus affecting the overall performance and safety of the battery pack.

[0101] Please refer to Figure 6 , Figure 6 An exploded view of a battery pack provided in an embodiment of this application in one specific embodiment.

[0102] In particular, along the second direction Y, and along the direction away from the water inlet 4, the contact thermal resistance between at least two liquid cooling plates 1 and the corresponding battery cells 2 decreases sequentially.

[0103] In this embodiment, as Figure 6As shown, along the second direction Y, and along the direction away from the water inlet 4, by successively reducing the contact thermal resistance between at least two liquid cooling plates 1 and the corresponding battery cells 2, the heat exchange efficiency of at least two liquid cooling plates 1 can be successively increased, that is, the heat exchange capacity can be successively increased. This can reduce the heat exchange capacity of the liquid cooling plates 1 in the area near the water inlet 4 in the battery pack 10, and / or simultaneously increase the heat exchange capacity of the liquid cooling plates 1 in the area away from the water inlet 4 in the battery pack 10. This reduces the difference in heat exchange capacity of liquid cooling plates 1 at different positions in the battery pack 10, improves the uniformity of heat exchange capacity of each liquid cooling plate 1 in the battery pack 10, thereby reducing the temperature difference between battery cells 2 in the battery pack 10 and making the temperature field distribution of the battery pack 10 more uniform. Specifically, for the heating operation of the battery pack 10, improving the heat exchange capacity of the liquid cooling plate 1 located away from the water inlet 4 makes it easier to raise the temperature of the battery cells 2 at that location. This reduces the temperature difference between the battery cells 2 and prevents localized overcooling of the battery cells 2, thereby improving the utilization rate of the charging current and enhancing the charging efficiency of the battery pack 10. Conversely, for the cooling operation of the battery pack 10, improving the heat exchange capacity of the liquid cooling plate 1 located away from the water inlet 4 makes it easier to lower the temperature of the battery cells 2 at that location. This reduces the temperature difference between the battery cells 2 and prevents localized overheating of the battery cells 2, thereby slowing down battery aging and extending the lifespan of the battery pack 10. Furthermore, reducing the temperature difference between the battery cells within the battery pack 10 ensures that the battery cells 2 within the battery pack 10 operate at a more uniform level, thus improving the overall performance of the battery pack 10.

[0104] Furthermore, compared to reducing the flow rate difference of the cooling medium in each liquid cooling plate by changing the flow channels and the arrangement of the flow channel openings, the embodiment of this application adjusts the heat exchange capacity of each liquid cooling plate 1 by adjusting the contact thermal resistance between the liquid cooling plate 1 at different positions in the battery pack 10 and the corresponding battery cell 2. This enables the design of the flow channels and flow channel openings in each liquid cooling plate 1 to be unified, thereby reducing the manufacturing difficulty, facilitating the unified assembly of the liquid cooling plates, and making it easier to manufacture and implement.

[0105] Please refer to Figure 7 , Figure 7 This is a schematic diagram of the structure of the liquid cooling plate provided in an embodiment of this application in a specific embodiment.

[0106] like Figure 7 As shown, the liquid cooling plate 1 includes a plate body 15 and a thermally conductive medium layer 16, which is disposed on the surface of the plate body 15. The thermally conductive medium layer 16 is used to fill the microscopic gap between the plate body 15 and the battery cell 2, reducing the contact thermal resistance caused by air, thereby improving the heat transfer efficiency of the cooling plate 1.

[0107] The thermally conductive layer 16 can be made of metal oxides, such as aluminum oxide, yttrium oxide, zirconium oxide, titanium dioxide, chromium oxide, etc. Alternatively, it can be made of polymers, such as polyimide (PI), polyhexamethylene terephthalamide (PA6T), polynonamethylene terephthalamide (PA9T), polyphenylene sulfide (PPS), polyethylene terephthalate (PET), and polyphenylene ether (PPS). Materials used include polyether (PPE), polyethylene (PE), polyetherimide (PEI), polyoxymethylene (POM), polylauryllactam (PA12), polysulfone (PSU), polyetheretherketone (PEEK), epoxy resin (EP), polyvinyl chloride (PVC), polyurethane (PU), polytetrafluoroethylene (PTFE), polypropylene (PP), acrylic acid (AA), and their composite materials. Of course, the material of the thermally conductive layer 16 can also be silicone, ceramic, aluminum foil, copper foil, etc., and the specific choice can be made according to actual needs; no restrictions are imposed here.

[0108] Preferably, the thermally conductive medium layer 16 can be made of a material with a thermal conductivity of 0.01 W / (m·K) to 30 W / (m·K) to meet the heat exchange requirements of the liquid cooling plate 1. The specific settings can be made according to actual needs and are not limited here.

[0109] Specifically, a thermally conductive medium layer can be formed on the surface of the plate 15 by oxidation, electroplating, spraying, or bonding. Of course, the thermally conductive medium layer 16 can also be formed by other methods. The specific method can be set according to actual needs and is not limited here.

[0110] Exemplarily, the thermally conductive medium layer 16 may be an insulating oxide film formed on the surface of the plate 15 by an oxidation method. Exemplarily, the thermally conductive medium layer 16 may be an insulating metallic or non-metallic coating deposited on the surface of the plate 15 by an electroplating method. Exemplarily, the thermally conductive medium layer 16 may be an insulating film layer formed on the surface of the plate 15 by a spraying method, specifically, insulating material may be sprayed onto the surface of the plate 15 using high temperature or high pressure. Exemplarily, the thermally conductive medium layer 16 may be formed by adhering insulating film material to the surface of the plate 15 by an adhesive method.

[0111] Specifically, the thickness of the heat-conducting medium layer 16 is less than or equal to 10 mm. For example, the thickness of the heat-conducting medium layer 16 can be 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, etc. The specific thickness can be set according to actual needs and is not limited here.

[0112] If the thickness of the thermally conductive medium layer 16 is too thick, for example, greater than 10mm, the contact thermal resistance of the liquid cooling plate 1 will be too high, resulting in weak heat exchange capacity. This will prevent timely heat exchange with the battery cells 2 in contact with the liquid cooling plate 1, reducing the overall performance of the battery pack 10, decreasing its thermal management efficiency, increasing energy consumption, hindering charging efficiency, and shortening its lifespan. Therefore, when the thickness of the thermally conductive medium layer 16 is less than or equal to 10mm, the contact thermal resistance of the liquid cooling plate 1 is moderate, meeting various heat exchange requirements, increasing the design freedom of the battery pack 10, ensuring its overall performance, improving its thermal management efficiency, saving energy, and also improving its charging efficiency and lifespan.

[0113] It should be noted that the contact thermal resistance between the liquid cooling plate 1 and the corresponding battery cell 2 is affected by the contact area, the thickness of the thermally conductive medium layer, and the thermal conductivity of the thermally conductive material itself. Therefore, the contact thermal resistance between the liquid cooling plate 1 and the corresponding battery cell 2 can be adjusted by adjusting the contact area between the liquid cooling plate 1 and the corresponding battery cell 2, the thickness of the thermally conductive medium layer, and / or the thermally conductive material of the thermally conductive medium layer.

[0114] One of the methods described above can be used to adjust the contact thermal resistance between at least two liquid cooling plates 1 and the corresponding battery cells 2 in the battery pack 10. Alternatively, multiple methods can be combined to adjust the contact thermal resistance between at least two liquid cooling plates 1 and the corresponding battery cells 2 in the battery pack 10. Of course, other methods can also be used to adjust the contact thermal resistance between at least two liquid cooling plates 1 and the corresponding battery cells 2 in the battery pack 10 to balance the heat exchange capacity of the liquid cooling plates 1 at different locations in the battery pack 10. The specific settings can be made according to actual needs and are not limited here.

[0115] For example, in a battery pack with 28 rows of cells and dual large-area liquid cooling, the contact surfaces of the liquid cooling plates within the battery pack are adhered with 0.1mm thick epoxy resin (EP) thermally conductive adhesive paper with a thermal conductivity of 0.2W / m·K. Simulation results show that when the water pump is at full load, the cumulative flow rate of the liquid cooling plates on both sides of the first row of cells near the inlet is 20% higher than that on both sides of rows 2 to 28 (the transient flow rate difference under non-full load can reach 30% to 50%). Since the contact thermal resistance between the liquid cooling plates and the corresponding cells is the same at all locations within the battery pack, the heat exchange capacity of the liquid cooling plates in areas with higher or lower heat exchange capacity due to flow rate differences cannot be adjusted. The temperature difference between the cells within the battery pack remains significant, with a maximum temperature difference of 4.1℃ during room temperature fast charging thermal stability. This severely affects the charging current step-by-step jump path during charging, resulting in a charging time of 13.3 minutes and low charging efficiency.

[0116] To reduce the temperature difference between the cells within the battery pack and improve charging efficiency, the heat transfer capacity of the liquid cooling plates in high-heat-transfer areas can be reduced. For example, the 0.1mm epoxy resin (EP) thermally conductive adhesive paper (thermal conductivity 0.2W / m·K) affixed to the contact surface of the liquid cooling plates on both sides of the first row of cells near the water inlet can be replaced with 0.1mm silicone insulating adhesive paper (thermal conductivity 0.16W / m·K), while the epoxy resin (EP) thermally conductive adhesive paper remains on the liquid cooling plates in other locations. This solution reduces the thermal conductivity of the thermally conductive adhesive paper on both sides of the first row of cells, thereby increasing the contact thermal resistance of the liquid cooling plates on both sides of the first row of cells and thus reducing their heat transfer capacity. Compared to a solution where the contact thermal resistance between the liquid cooling plates and the corresponding cells in each location of the battery pack is the same, a solution that reduces the thermal conductivity of the thermally conductive adhesive paper on both sides of the liquid cooling plates near the first row of cells near the water inlet, thereby reducing its heat exchange capacity, can reduce the temperature difference between the cells in the battery pack by 1.8℃ and shorten the charging time by 1.5 minutes during room temperature fast charging.

[0117] Alternatively, the temperature difference between cells within the battery pack can be reduced and charging efficiency improved by increasing the heat transfer capacity of the liquid cooling plates in areas with low heat transfer intensity. For example, the 0.1mm epoxy resin (EP) thermally conductive adhesive paper (thermal conductivity 0.2W / m·K) adhered to the contact surface of the liquid cooling plates on both sides of the 2nd to 28th rows of cells away from the water inlet can be replaced with 0.05mm acrylic (AA) insulating varnish (thermal conductivity 0.24W / m·K), while the epoxy resin (EP) thermally conductive adhesive paper remains on the liquid cooling plates in other locations. In this solution, the thickness of the thermally conductive adhesive paper on the liquid cooling plates on both sides of the 2nd to 28th rows of cells away from the water inlet is reduced, and the thermal conductivity is increased, thereby reducing the contact thermal resistance between the liquid cooling plates on both sides of the 2nd to 28th rows of cells and the corresponding cells, thus improving their heat transfer capacity. Compared to a solution where the contact thermal resistance between the liquid cooling plates and the corresponding cells in each location of the battery pack is the same, a solution that reduces the thickness of the thermally conductive adhesive paper on both sides of the liquid cooling plates of the cells in rows 2 to 28 furthest from the water inlet and increases the thickness of the thermally conductive adhesive paper to improve its heat exchange capacity can reduce the cell temperature difference by 3.0℃ and shorten the charging time by 3.3 minutes during room temperature fast charging.

[0118] Further, please refer to Figure 8 , Figure 8 An exploded view of the battery pack provided in an embodiment of this application in another specific embodiment. For example... Figure 8 As shown, along the first direction X of the battery pack 10, the liquid cooling plate 1 includes at least two contact areas. Each battery cell 2 has its opposite side surfaces along the second direction Y in contact with the corresponding contact areas on the liquid cooling plate 1, so that the liquid cooling plate 1 can perform more targeted heat exchange on the two side surfaces of each battery cell 2, thereby achieving heating or cooling of the battery cell 2.

[0119] For example, such as Figure 8As shown, along the second direction Y, and in a direction away from the water inlet, the battery pack 10 sequentially includes a first liquid cooling plate 1a, a second liquid cooling plate 1b, and a third liquid cooling plate 1c. Three battery cells 2 are disposed between two adjacent liquid cooling plates. Along the first direction of the battery pack 10, and in a direction away from the flow channel inlet 11, each liquid cooling plate includes three corresponding contact areas, namely the first contact area 14a, the second contact area 14b, and the third contact area 14c. The contact thermal resistances of the first contact area 14a, the second contact area 14b, and the third contact area 14c of the first liquid cooling plate 1a with the corresponding battery cell 2 are R11, R12, and R13, respectively. The contact thermal resistances of the first contact area 14a, the second contact area 14b, and the third contact area 14c of the second liquid cooling plate 1b with the corresponding battery cell 2 are R21, R22, and R23, respectively. The contact thermal resistances of the first contact area 14a, the second contact area 14b, and the third contact area 14c of the third liquid cooling plate 1c with the corresponding battery cell 2 are R31, R32, and R33, respectively. By controlling R11 > R21 > R31, R21 > R22 > R23, and R31 > R32 > R33, the heat exchange efficiency of the contact areas of the first liquid cooling plate 1a, the second liquid cooling plate 1b, and the third liquid cooling plate 1c can be sequentially increased, i.e., the heat exchange capacity can be sequentially increased, thereby reducing the thermal resistance of the battery pack 10. The heat transfer capacity of the contact area of ​​the liquid cooling plate 1 near the water inlet 4 is reduced, which means the heat transfer capacity of the contact area of ​​the first liquid cooling plate 1a is reduced. At the same time, the heat transfer capacity of the contact areas of the liquid cooling plates in the battery pack 10 away from the water inlet 4 is sequentially increased, which means the heat transfer capacity of the contact areas of the second liquid cooling plate 1b and the third liquid cooling plate 1c is increased. This reduces the difference in heat transfer capacity between the first liquid cooling plate 1a, the second liquid cooling plate 1b and the third liquid cooling plate 1c, and improves the uniformity of the heat transfer capacity of the first liquid cooling plate 1a, the second liquid cooling plate 1b and the third liquid cooling plate 1c. This further reduces the temperature difference between the cells 2 in the battery pack 10, making the temperature field distribution of the battery pack 10 more uniform. This is beneficial to improving the charging efficiency and service life of the battery pack 10, and ensuring that the cells 2 in the battery pack 10 are in the same working state, thereby improving the overall performance and safety performance of the battery pack 10.

[0120] In some other embodiments, the number of liquid cooling plates 1 in the battery pack 10 can also be 2, 4, 5, 10, 20, 30, etc., and the number of rows of battery cells 2 can also be 1 row, 3 rows, 4 rows, 9 rows, 19 rows, 29 rows, etc., to meet the power requirements of different vehicles. The specific settings can be made according to actual needs and are not limited here.

[0121] In one specific embodiment, such as Figure 4 and Figure 6 As shown, along the second direction Y and in the direction away from the water inlet 4, the thickness of the heat-conducting medium layer of at least two liquid cooling plates 1 decreases sequentially.

[0122] In this embodiment, since the thickness of the thermally conductive medium layer is proportional to the contact thermal resistance, the greater the thickness of the thermally conductive medium layer, the greater the contact thermal resistance. Therefore, when the thickness of the thermally conductive medium layer of at least two liquid cooling plates 1 decreases sequentially along the second direction Y and along the direction away from the water inlet 4, the contact thermal resistance between the two liquid cooling plates 1 and the corresponding battery cell 2 can be reduced sequentially, thereby increasing the heat exchange capacity of at least two liquid cooling plates 1 sequentially.

[0123] Wherein, when the liquid cooling plate 1 includes multiple contact areas, along the second direction Y, and in the direction away from the water inlet 4, the thickness of the heat-conducting medium layer corresponding to at least two contact areas of the liquid cooling plate 1 decreases sequentially. For example, as Figure 8 As shown, the thickness of the first thermally conductive medium layer in the first contact area 14a of the first liquid cooling plate 1a, the second liquid cooling plate 1b, and the third liquid cooling plate 1c decreases sequentially; the thickness of the second thermally conductive medium layer in the second contact area 14b of the first liquid cooling plate 1a, the second liquid cooling plate 1b, and the third liquid cooling plate 1c decreases sequentially; and the thickness of the third thermally conductive medium layer in the third contact area 14c of the first liquid cooling plate 1a, the second liquid cooling plate 1b, and the third liquid cooling plate 1c decreases sequentially. This allows the contact thermal resistance between the contact areas of the first liquid cooling plate 1a, the second liquid cooling plate 1b, and the third liquid cooling plate 1c and the corresponding battery cell 2 to decrease sequentially, thereby increasing the heat exchange capacity of the contact areas of the first liquid cooling plate 1a, the second liquid cooling plate 1b, and the third liquid cooling plate 1c sequentially.

[0124] In one specific embodiment, such as Figure 4 and Figure 6 As shown, along the second direction Y and in the direction away from the water inlet 4, the thermal conductivity of the thermally conductive medium layer of at least two liquid cooling plates 1 increases sequentially.

[0125] In this embodiment, since the thermal conductivity of the thermally conductive medium layer is inversely proportional to the contact thermal resistance, the larger the thermal conductivity of the thermally conductive medium layer, the smaller the contact thermal resistance. Therefore, when the thermal conductivity of the thermally conductive medium layer of at least two liquid cooling plates 1 increases sequentially along the second direction Y and along the direction away from the water inlet 4, the contact thermal resistance between the two liquid cooling plates 1 and the corresponding battery cell 2 can be reduced sequentially, thereby increasing the heat exchange capacity of at least two liquid cooling plates 1 sequentially.

[0126] Wherein, when the liquid cooling plate 1 includes multiple contact areas, along the second direction Y, and in the direction away from the water inlet 4, the thermal conductivity of the heat-conducting medium layers corresponding to at least two liquid cooling plates 1 increases sequentially. For example, as... Figure 8As shown, the thermal conductivity K11, K21, and K31 of the first heat-conducting medium layer in the first contact area 14a of the first liquid cooling plate 1a, the second liquid cooling plate 1b, and the third liquid cooling plate 1c increases sequentially, i.e., K11 < K21 < K31. Similarly, the thermal conductivity K12, K22, and K32 of the second heat-conducting medium layer in the second contact area 14b of the first liquid cooling plate 1a, the second liquid cooling plate 1b, and the third liquid cooling plate 1c increases sequentially, i.e., K12 < K22 < K32. The first liquid cooling plate 1... a. The thermal conductivity of the third heat-conducting medium layer in the third contact area 14c of the second liquid cooling plate 1b and the third liquid cooling plate 1c increases sequentially, i.e., K13 < K23 < K33. This allows the contact thermal resistance between the contact area of ​​the first liquid cooling plate 1a, the second liquid cooling plate 1b and the third liquid cooling plate 1c and the corresponding battery cell 2 to decrease sequentially, thereby increasing the heat exchange capacity of the contact area of ​​the first liquid cooling plate 1a, the second liquid cooling plate 1b and the third liquid cooling plate 1c sequentially.

[0127] Specifically, the thermal conductivity of the liquid cooling plate 1 can be adjusted by changing the material of its heat-conducting medium layer. For example, such as... Figure 8 As shown, the heat-conducting medium layers of the first liquid cooling plate 1a, the second liquid cooling plate 1b, and the third liquid cooling plate 1c can all be made of different materials.

[0128] In one specific embodiment, such as Figure 4 and Figure 6 As shown, along the second direction Y, and in the direction away from the water inlet 4, the contact area between the multiple liquid cooling plates 1 and the corresponding battery cells 2 increases sequentially.

[0129] In this embodiment, since the contact area is inversely proportional to the contact thermal resistance, the larger the contact area, the smaller the contact thermal resistance. Therefore, when the contact area between the multiple liquid cooling plates 1 and the corresponding battery cells 2 increases sequentially along the second direction Y and in the direction away from the water inlet 4, the contact thermal resistance between the two liquid cooling plates 1 and the corresponding battery cells 2 can be reduced sequentially, thereby increasing the heat exchange capacity of at least two liquid cooling plates 1 sequentially.

[0130] Wherein, when the liquid cooling plate 1 includes multiple contact areas, along the second direction Y, and in the direction away from the water inlet 4, the contact area between the contact areas of the multiple liquid cooling plates 1 and the corresponding battery cells 2 increases sequentially. For example, as shown... Figure 8As shown, the thermal conductivity A11, A21, and A31 of the first heat-conducting medium layer in the first contact area 14a of the first liquid cooling plate 1a, the second liquid cooling plate 1b, and the third liquid cooling plate 1c increases sequentially, i.e., A11 < A21 < A31. Similarly, the thermal conductivity A12, A22, and A32 of the second heat-conducting medium layer in the second contact area 14b of the first liquid cooling plate 1a, the second liquid cooling plate 1b, and the third liquid cooling plate 1c increases sequentially, i.e., A12 < A22 < A32. The first liquid cooling plate 1... a. The thermal conductivity A13, A23 and A33 of the third heat-conducting medium layer in the third contact area 14c of the second liquid cooling plate 1b and the third liquid cooling plate 1c increases sequentially, i.e. A13 < A23 < A33. This enables the contact thermal resistance between the contact area of ​​the first liquid cooling plate 1a, the second liquid cooling plate 1b and the third liquid cooling plate 1c and the corresponding battery cell 2 to decrease sequentially, thereby increasing the heat exchange capacity of the contact area of ​​the first liquid cooling plate 1a, the second liquid cooling plate 1b and the third liquid cooling plate 1c sequentially.

[0131] Specifically, the planar contact area between the contact area of ​​each liquid cooling plate 1 and the corresponding battery cell 2 within the battery pack 10 can be adjusted macroscopically. For example, by setting grooves or protrusions in the contact area, the planar contact area between the contact area of ​​each liquid cooling plate 1 and the corresponding battery cell 2 within the battery pack 10 can be adjusted. Of course, the actual contact area between the contact area of ​​each liquid cooling plate 1 and the corresponding battery cell 2 within the battery pack 10 can also be adjusted by adjusting the surface roughness or other surface microstructures of the contact surface between the contact area of ​​each liquid cooling plate 1 and the corresponding battery cell 2 within the battery pack 10, or by setting a microstructure gap layer, such as an air layer or a nanoparticle-reinforced interface layer, between the contact area and the corresponding battery cell 2. The specific settings can be made according to actual needs and are not limited here.

[0132] In the above embodiments, as Figure 8 As shown, along the second direction Y, the ratio of the maximum contact thermal resistance to the minimum contact thermal resistance between the liquid cooling plate 1 at both ends of the battery pack 10 and the corresponding cell 2 is between 1 and 3. For example, the ratio of the maximum contact thermal resistance to the minimum contact thermal resistance can be 1, 1.2, 1.5, 1.8, 2, 2.2, 2.5, 2.8, 3, etc. The specific value can be set according to actual needs and is not limited here.

[0133] For example, when the liquid cooling plate 1 includes multiple contact areas, such as Figure 8 As shown, the ratios of the contact thermal resistances R11, R12, and R13 between the first contact area 14a, the second contact area 14b, and the third contact area 14c of the first liquid cooling plate 1a and the corresponding battery cell 2, and the contact thermal resistances R31, R32, and R33 between the first contact area 14a, the second contact area 14b, and the third contact area 14c of the third liquid cooling plate 1c and the corresponding battery cell 2, satisfy 1≤R11 / R31≤3, 1≤R12 / R32≤3, and 1≤R13 / R33≤3, respectively.

[0134] Among them, such as Figure 8 As shown, if the ratio of the maximum and minimum contact thermal resistance between the contact area of ​​the liquid cooling plate 1 at both ends of the battery pack 10 and the corresponding cell 2 is too small, for example, less than 1, then the difference in contact thermal resistance between the contact areas of at least two liquid cooling plates 1 is small. When there is a large temperature difference between the cells 2 of the battery pack 10, the liquid cooling plate 1 with high heat transfer intensity near the water inlet 4 cannot significantly reduce the heat transfer capacity of the contact area of ​​the liquid cooling plate 1 in that area, and the liquid cooling plate 1 with low heat transfer intensity away from the water inlet 4 cannot significantly improve the heat transfer capacity of the contact area of ​​the liquid cooling plate 1 in that area. Therefore, it cannot play a good role in balancing the heat transfer capacity of the liquid cooling plate 1 at different positions in the battery pack 10, and the temperature difference between the cells 2 in the battery pack 10 is still large. If the ratio of the maximum to the minimum contact thermal resistance between the contact area of ​​the liquid cooling plate 1 at both ends of the battery pack 10 and the corresponding cell 2 is too large, for example, less than 3, then the difference in contact thermal resistance between the contact areas of at least two liquid cooling plates 1 is too large. This can easily lead to an excessively large contact thermal resistance between the contact area of ​​the high heat exchange intensity liquid cooling plate 1 near the water inlet 4 and the corresponding cell 2, thereby reducing the heat exchange capacity of the liquid cooling plate 1 in that area and preventing it from playing a good role in heating or cooling.

[0135] Therefore, when the ratio of the maximum contact thermal resistance to the minimum contact thermal resistance between the liquid cooling plates 1 at both ends of the battery pack 10 and the corresponding battery cell 2 along the second direction Y is between 1 and 3, it can ensure that the liquid cooling plates 1 at each position in the battery pack 10 have good heat exchange capacity, and at the same time, it can play a good role in balancing the heat exchange capacity of the liquid cooling plates 1 at different positions in the battery pack 10, further reducing the temperature difference between the battery cells 2 in the battery pack 10.

[0136] Please refer to Figure 9 , Figure 9 A cross-sectional view of a liquid cooling plate provided in an embodiment of this application in one specific embodiment.

[0137] like Figure 9 As shown, a flow channel 13 is provided inside the liquid cooling plate 1. Along the first direction X, the two ends of the flow channel 13 are connected to the flow channel inlet 11 and the flow channel outlet 12. Multiple flow channels 13 can be provided inside the liquid cooling plate 1. Specifically, the flow channel 13 can be one or a combination of serpentine flow channels or straight flow channels to balance the heat exchange efficiency and temperature uniformity of the liquid cooling plate 1. The specific configuration can be determined according to actual needs and is not limited here.

[0138] The serpentine flow channel increases the flow path length of the cooling medium within the liquid cooling plate 1, thereby increasing the contact time between the cooling medium and the liquid cooling plate 1 and improving the heat exchange efficiency of the liquid cooling plate. Furthermore, the tortuous design of the serpentine flow channel generates disturbances in the cooling medium as it flows within it, contributing to improved heat exchange uniformity. Compared to the serpentine flow channel, the cooling medium experiences less resistance flowing in a straight flow channel, enabling heat transfer to be completed in a relatively short time. By rationally configuring serpentine and / or straight flow channels within the liquid cooling plate 1, the heat exchange capacity of the liquid cooling plate 1 can be effectively optimized, allowing it to handle heat sources with different heat flux densities. This also helps to equalize the temperature in different areas of the liquid cooling plate 1 within a limited space, thus improving the temperature uniformity performance of the liquid cooling plate 1.

[0139] For example, such as Figure 9 As shown, the liquid cooling plate 1 includes a first flow channel 13a, a second flow channel 13b, a third flow channel 13c, and a fourth flow channel 13b arranged sequentially along the third direction Z. The first flow channel 13a and the fourth flow channel 13b are serpentine flow channels, while the second flow channel 13b and the third flow channel 13c are straight-through flow channels. By combining the serpentine flow channels and the straight-through flow channels, the heat exchange efficiency and temperature uniformity of the liquid cooling plate 1 can be improved.

[0140] In some other embodiments, the flow channels 13 in the liquid cooling plate 1 can also be 1, 2, 3, 5, 6, etc., to better balance the heat exchange efficiency and temperature uniformity of the liquid cooling plate 1 and meet the different heat exchange requirements of the liquid cooling plate 1. The specific settings can be made according to actual needs and are not limited here.

[0141] As the cooling medium flows from the inlet 11 into the channel 13 and out through the outlet 12, its temperature changes due to continuous heat exchange between the liquid cooling plate 1 and the battery cell 2. This creates temperature differences between the various contact areas of the liquid cooling plate 1, gradually reducing its heat exchange capacity. Specifically, along the first direction of the battery pack 10, and in the direction away from the inlet 11, the heat exchange capacity of at least two contact areas decreases sequentially. If the contact thermal resistance of each contact area on the liquid cooling plate remains constant, the heat exchange capacity of areas with higher or lower heat exchange capacity on the liquid cooling plate cannot be adjusted. This can easily lead to excessive temperature differences between the battery cells within the battery pack, thereby affecting the charging performance and lifespan of the battery pack.

[0142] Please refer to Figure 10 , Figure 10 This is a partially exploded view of the battery pack provided in one specific embodiment of the present application, as shown below. Figure 10 As shown, along the first direction X and in the direction away from the flow channel inlet 11, the contact thermal resistance between at least two contact areas and the corresponding cell 2 decreases sequentially.

[0143] In this embodiment, as Figure 10As shown, since contact thermal resistance is inversely proportional to heat transfer efficiency, the larger the contact thermal resistance, the lower the heat transfer efficiency. Therefore, when the contact thermal resistance between at least two contact areas and the corresponding cell 2 decreases sequentially along the first direction X and in the direction away from the flow channel inlet 11, the heat transfer efficiency of at least two contact areas increases sequentially, that is, the heat transfer capacity increases sequentially. This can reduce the heat transfer capacity of the contact area on the liquid cooling plate 1 near the flow channel inlet 11 and / or sequentially increase the heat transfer capacity of the contact area on the liquid cooling plate 1 away from the flow channel inlet 11, so as to reduce the difference in heat transfer capacity of each contact area of ​​the liquid cooling plate 1, improve the uniformity of heat transfer capacity of each contact area of ​​the liquid cooling plate, so as to improve the uniformity of the temperature change rate between each heat transfer area and the corresponding contact cell 2, reduce the temperature difference between cells 2, improve the temperature uniformity of the liquid cooling plate 1, and make the temperature field distribution of the battery pack 10 more uniform. Specifically, for the heating condition of the battery pack 10, improving the heat exchange capacity of the contact area far from the flow channel inlet 11 makes it easier to raise the temperature of the cell 2 at that location. This reduces the temperature difference between the cells 2 and prevents localized overcooling of the cells 2, thereby improving the utilization rate of the charging current and enhancing the charging efficiency of the battery pack 10. Conversely, for the cooling condition of the battery pack 10, improving the heat exchange capacity of the contact area far from the flow channel inlet 11 makes it easier to lower the temperature of the cell 2 at that location. This reduces the temperature difference between the cells 2 and prevents localized overheating of the cells 2, thereby slowing down battery aging and extending the lifespan of the battery pack 10. Furthermore, a reduced temperature difference between the cells within the battery pack 10 ensures that the cells 2 operate at a more uniform level, thus improving the overall performance of the battery pack 10.

[0144] Furthermore, in this embodiment, the heat exchange capacity of each contact area of ​​the liquid cooling plate 1 is adjusted only by adjusting the contact thermal resistance between the contact area and the corresponding cell 2, without the need to adjust the temperature and flow rate of the cooling medium inside the liquid cooling plate 1. This can further improve the thermal management efficiency of the battery pack 10, save energy, and is easy to manufacture and implement.

[0145] For example, such as Figure 10As shown, three battery cells 2 are disposed between two adjacent liquid cooling plates 1. Along the first direction of the battery pack 10 and along the direction away from the flow channel inlet 11, the liquid cooling plate 1 includes three corresponding contact areas, namely the first contact area 14a, the second contact area 14b and the third contact area 14c. The opposite side surfaces of the three battery cells 2 along the second direction Y are in contact with the corresponding first contact area 14a, the second contact area 14b and the third contact area 14c on the liquid cooling plate in sequence. In this design, the thermal resistance between the first contact area 14a and the corresponding battery cell 2 is R1, the thermal resistance between the second contact area 14b and the corresponding battery cell 2 is R2, and the thermal resistance between the third contact area 14c and the corresponding battery cell 2 is R3. By controlling R1 > R2 > R3, the heat transfer efficiency of the first contact area 14a, the second contact area 14b, and the third contact area 14c of the liquid cooling plate 1 can be increased sequentially, i.e., the heat transfer capacity can be increased sequentially. This reduces the heat transfer capacity of the contact area near the flow channel inlet 11, i.e., reduces the heat transfer capacity of the first contact area 14a, while simultaneously increasing the heat transfer capacity of the contact areas farther from the flow channel inlet 11, i.e., increases the heat transfer capacity of the third contact area 14c. The heat exchange capacity of the second contact area 14b and the third contact area 14c is reduced to decrease the difference in heat exchange capacity among the first contact area 14a, the second contact area 14b and the third contact area 14c. This improves the uniformity of heat exchange capacity among the first contact area 14a, the second contact area 14b and the third contact area 14c of the liquid cooling plate 1, reduces the temperature difference between the cells 2, improves the temperature uniformity of the liquid cooling plate 1, and makes the temperature field distribution of the battery pack 10 more uniform. This is beneficial to improving the charging efficiency and service life of the battery pack 10, and ensuring that the cells 2 in the battery pack 10 are in the same working state, thereby improving the overall performance and safety performance of the battery pack 10.

[0146] Among them, such as Figure 10As shown, in the process of optimizing the contact thermal resistance of each contact area of ​​the liquid cooling plate 1, for example, the contact thermal resistance of the contact area near the flow channel inlet 11 can be increased, and the heat transfer capacity of the contact area near the flow channel inlet 11 can be reduced, thereby reducing the difference in heat transfer capacity between the contact area near the flow channel inlet 11 and the contact area near the flow channel outlet 12, and improving the uniformity of heat transfer capacity of each contact area of ​​the liquid cooling plate 1; for example, the contact thermal resistance of the contact area near the flow channel outlet 12 can also be reduced, and the heat transfer capacity of the contact area near the flow channel outlet 12 can be increased, thereby reducing the difference in heat transfer capacity between the contact area near the flow channel inlet 11 and the contact area near the flow channel outlet 12, and improving the uniformity of heat transfer capacity of each contact area of ​​the liquid cooling plate 1. The heat exchange capacity of each contact area is balanced, and the heat exchange capacity of the contact area near the flow channel inlet 11 is also maintained, thereby further improving the overall heat exchange capacity of the liquid cooling plate 1. For example, when the difference in heat exchange capacity between the two contact areas of the liquid cooling plate 1 along the first direction X is too large, the contact thermal resistance of the contact area near the flow channel inlet 11 can be increased, while the contact thermal resistance of the contact area near the flow channel outlet 12 can be reduced. This reduces the heat exchange capacity of the contact area near the flow channel inlet 11 while increasing the heat exchange capacity of the contact area near the flow channel outlet 12, thereby reducing the difference in heat exchange capacity among the contact areas of the liquid cooling plate 1 and ensuring the balanced effect of heat exchange capacity among the contact areas of the liquid cooling plate 1.

[0147] In some other embodiments, the number of battery cells 2 between two adjacent liquid cooling plates 1 can be two, four, five, six, etc. Along the first direction of the battery pack 10 and in the direction away from the flow channel inlet 11, the liquid cooling plate 1 can include two, four, five, six contact areas, etc. The number of contact areas on the liquid cooling plate 1 can be the same as the number of battery cells 2 between two adjacent liquid cooling plates 1, so that the battery cells 2 and the contact areas on the liquid cooling plate 1 are arranged in a one-to-one correspondence. This further improves the uniformity of the temperature change rate between each heat exchange area and the corresponding contact heat exchange battery cell 2, reduces the temperature difference between battery cells 2, and further improves the temperature uniformity of the liquid cooling plate 1. Of course, the number of contact areas on the liquid cooling plate 1 can be less than the number of battery cells 2 between two adjacent liquid cooling plates 1, which can improve the temperature uniformity of the liquid cooling plate 1 while reducing the manufacturing difficulty of the liquid cooling plate 1 and saving costs.

[0148] Furthermore, along the first direction X, the ratio of the maximum to the minimum contact thermal resistance between the contact areas at both ends of the liquid cooling plate 1 and the corresponding battery cell 2 is between 1 and 3. For example, the ratio of the maximum to the minimum contact thermal resistance can be 1, 1.2, 1.5, 1.8, 2, 2.2, 2.5, 2.8, 3, etc., and can be set according to actual needs, without limitation here. For example, such as... Figure 10As shown, the ratio of the contact thermal resistance R1 between the first contact area 14a and the corresponding cell 2 to the contact thermal resistance R3 between the third contact area 14c and the corresponding cell 2 satisfies 1≤R1 / R3≤3.

[0149] Among them, such as Figure 10 As shown, if the ratio of the maximum to the minimum contact thermal resistance between the contact areas at both ends of the liquid cooling plate 1 and the corresponding battery cell 2 is too small, for example, less than 1, then the difference in contact thermal resistance between at least two contact areas is small. When there is a large temperature difference between the battery cells 2 in the battery pack 10, along the first direction X, for the contact area with high heat transfer intensity near the flow channel inlet 11, it cannot significantly reduce the heat transfer capacity of the contact area. For the contact area with low heat transfer intensity far from the flow channel inlet 11, it cannot significantly improve the heat transfer capacity of the contact area. Therefore, it cannot play a good role in balancing the heat transfer capacity of each contact area on the liquid cooling plate 1, and the temperature uniformity effect is poor. If the ratio of the maximum to the minimum contact thermal resistance between the contact areas at both ends of the liquid cooling plate 1 and the corresponding battery cell 2 is too large, for example, greater than 3, then the difference in contact thermal resistance between at least two contact areas will be too large. This will easily lead to an excessively large contact thermal resistance between the high heat transfer intensity contact area near the flow channel inlet 11 and the corresponding battery cell 2, resulting in poor heat transfer capacity. Consequently, the heat transfer capacity of the liquid cooling plate 1 will be reduced, and it will not be able to play a good role in heating or cooling.

[0150] Therefore, when the ratio of the maximum contact thermal resistance to the minimum contact thermal resistance between the contact areas at both ends of the liquid cooling plate 1 and the corresponding battery cell 2 along the first direction X is between 1 and 3, it can ensure that the liquid cooling plate 1 has good heat exchange capacity, and at the same time, it can play a good role in balancing the heat exchange capacity of each contact area on the liquid cooling plate 1, thereby improving the temperature uniformity of the liquid cooling plate 1.

[0151] As mentioned above, the contact thermal resistance between the liquid cooling plate 1 and the corresponding battery cell 2 is affected by the contact area, the thickness of the thermally conductive medium layer, and the thermal conductivity of the thermally conductive material itself. Therefore, the contact thermal resistance between the contact area and the corresponding battery cell 2 can be adjusted by adjusting the contact area between the liquid cooling plate 1 and the corresponding battery cell 2, the thickness of the thermally conductive medium layer, and / or the thermally conductive material of the thermally conductive medium layer.

[0152] Please refer to Figure 11 , Figure 11 This is a schematic diagram of the structure of the liquid cooling plate provided in an embodiment of this application in another specific embodiment.

[0153] In one specific embodiment, such as Figure 11 As shown, along the first direction X and in the direction away from the flow channel inlet 11, the thickness of the thermally conductive medium layer 16 corresponding to at least two contact areas decreases sequentially.

[0154] In this embodiment, since the thickness of the thermally conductive medium layer 16 is proportional to the contact thermal resistance, the greater the thickness of the thermally conductive medium layer 16, the greater the contact thermal resistance. Therefore, when the thickness of the thermally conductive medium layer 16 corresponding to at least two contact areas decreases sequentially along the first direction X and along the direction away from the flow channel inlet 11, the contact thermal resistance between at least two contact areas and the corresponding battery cell 2 can be reduced sequentially, thereby increasing the heat exchange capacity of at least two contact areas sequentially.

[0155] For example, such as Figure 11 As shown, the thickness of the first thermally conductive medium layer 16a in the first contact area 14a is d1, the thickness of the second thermally conductive medium layer 16b in the second contact area 14b is d2, and the thickness of the third thermally conductive medium layer 16c in the third contact area 14c is d3. When d1 > d2 > d3, the contact thermal resistance between the first contact area 14a, the second contact area 14b, and the third contact area 14c and the corresponding battery cell 2 decreases sequentially, i.e., R1 > R2 > R3, and the heat transfer capacity of the first contact area 14a, the second contact area 14b, and the third contact area 14c increases sequentially.

[0156] In one specific embodiment, along the first direction X and in the direction away from the flow channel inlet 11, the thermal conductivity of the thermally conductive medium layer 16 corresponding to at least two contact areas increases sequentially.

[0157] In this embodiment, since the thermal conductivity of the thermally conductive medium layer 16 is inversely proportional to the contact thermal resistance, the larger the thermal conductivity of the thermally conductive medium layer 16, the smaller the contact thermal resistance. Therefore, when the thermal conductivity of the thermally conductive medium layer 16 corresponding to at least two contact areas increases sequentially along the first direction X and along the direction away from the flow channel inlet 11, the contact thermal resistance between at least two contact areas and the corresponding battery cell 2 can be reduced sequentially, thereby increasing the heat exchange capacity of at least two contact areas sequentially.

[0158] For example, such as Figure 11 As shown, the thermal conductivity of the first thermally conductive medium layer 16a in the first contact area 14a is K1, the thermal conductivity of the second thermally conductive medium layer 16b in the second contact area 14b is K2, and the thermal conductivity of the third thermally conductive medium layer 16c in the third contact area 14c is K3. When K1 < K2 < K3, the contact thermal resistance between the first contact area 14a, the second contact area 14b, and the third contact area 14c and the corresponding battery cell 2 decreases sequentially, i.e., R1 > R2 > R3, and the heat transfer capacity of the first contact area 14a, the second contact area 14b, and the third contact area 14c increases sequentially.

[0159] Specifically, the thermal conductivity can be adjusted by changing the material of the thermally conductive medium layer 16 corresponding to the contact area. For example, such as... Figure 11 As shown, the first thermally conductive layer 16a, the second thermally conductive layer 16b, and the third thermally conductive layer 16c can be formed using different materials.

[0160] In one specific embodiment, such as Figure 10 As shown, along the first direction X and in the direction away from the flow channel inlet 11, the contact area of ​​at least two contact areas with the corresponding battery cell 2 increases sequentially.

[0161] In this embodiment, since the contact area is inversely proportional to the contact thermal resistance, the larger the contact area, the smaller the contact thermal resistance. Therefore, when the contact area between at least two contact areas and the corresponding battery cell 2 increases sequentially along the first direction X and in the direction away from the flow channel inlet 11, the contact thermal resistance between at least two contact areas and the corresponding battery cell 2 can be reduced sequentially, thereby increasing the heat exchange capacity of at least two contact areas sequentially.

[0162] For example, such as Figure 10 As shown, the contact areas between the first contact area 14a, the second contact area 14b, and the third contact area 14c and the corresponding battery cell 2 are A1, A2, and A3, respectively. When A1 < A2 < A3, the contact thermal resistance between the first contact area 14a, the second contact area 14b, and the third contact area 14c and the corresponding battery cell 2 decreases sequentially, i.e., R1 > R2 > R3, and the heat transfer capacity of the first contact area 14a, the second contact area 14b, and the third contact area 14c increases sequentially.

[0163] Specifically, the planar contact area between the contact area and the corresponding cell 2 can be adjusted macroscopically, for example, by setting grooves or protrusions in the contact area. Alternatively, the actual contact area between the contact area and the corresponding cell 2 can be adjusted by adjusting the surface roughness or other microstructures of the contact surface, or by setting a microstructure gap layer, such as an air layer or a nanoparticle-reinforced interface layer. The specific adjustments can be made according to actual needs and are not limited here.

[0164] One of the above methods can be used to adjust the contact thermal resistance between the contact area and the corresponding battery cell 2. Alternatively, multiple methods can be combined to adjust the contact thermal resistance between the contact area and the corresponding battery cell 2. Of course, other methods can also be used to adjust the contact thermal resistance between the contact area and the corresponding battery cell 2 to balance the heat exchange capacity of each contact area on the liquid cooling plate 1. The specific settings can be made according to actual needs and are not limited here.

[0165] In the examples above, when designing the battery pack in this application, the current changes during the fast charging process of the battery pack can be simulated first, and the internal resistance, specific heat capacity, and thermal conductivity of the cells can be combined to calculate the temperature distribution and heat generation within the cells. Then, based on the temperature distribution and heat generation within the cells, the flow channels within the liquid cooling plate are designed to control the flow resistance and flow rate of the cooling medium within the liquid cooling plate, ensuring effective heat conduction through the liquid cooling plate. Furthermore, structural optimization (topology optimization and parameter optimization, etc.) is used to adjust the arrangement of the flow channels, making the temperature of the liquid cooling plate more uniform. Next, a three-dimensional thermo-fluid coupling model of the battery and the liquid cooling plate is established, and steady-state or transient simulations are used to calculate the temperature field of the constant contact thermal resistance liquid cooling plate, the temperature field of the battery surface, and the flow velocity of the fluid within each liquid cooling plate. Then, the temperature difference can be obtained from the constant contact thermal resistance liquid cooling plate temperature field and the battery surface temperature field. Combined with the flow rate, the high heat transfer intensity zone and the low heat transfer intensity zone in the battery pack can be determined. For the high heat transfer intensity zone, the contact thermal resistance between the liquid cooling plate and the corresponding cell in this area can be increased to reduce its heat transfer efficiency. For the low heat transfer intensity zone, the contact thermal resistance between the liquid cooling plate and the corresponding cell in this area can be reduced to increase its heat transfer efficiency, thereby improving the temperature uniformity of the liquid cooling plate in the battery pack. Specifically, the contact thermal resistance between the liquid cooling plate and the cell can be adjusted by adjusting the contact area between the liquid cooling plate and the cell, the thickness of the thermally conductive medium layer of the liquid cooling plate, and / or the material of the thermally conductive medium layer of the liquid cooling plate. Finally, parametric simulations were performed to verify the effects of different thermal resistance coating materials, thicknesses, and contact areas on the temperature field. Based on the simulation structure, different thermal resistance insulating materials, interface thicknesses, and / or contact areas were selected to treat the surface of the liquid cooling plate. Specifically, a corresponding thermally conductive medium layer could be formed on the surface of the liquid cooling plate through oxidation, electroplating, spraying, or adhesive bonding to improve the temperature uniformity of the liquid cooling plate in the battery pack, optimize the temperature distribution of the cells in the battery pack, and improve the thermal management performance of the battery.

[0166] Of course, the battery pack in this application can also be designed in other ways, and no restrictions are imposed here.

[0167] The same or similar parts between the various embodiments in this specification can be referred to mutually. In particular, the device embodiments and terminal embodiments are basically similar to the method embodiments, so the description is relatively simple, and the relevant parts can be referred to the description in the method embodiments.

[0168] The above descriptions are merely specific implementations of the embodiments of this application, but the protection scope of the embodiments of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in the embodiments of this application should be covered within the protection scope of the embodiments of this application. Therefore, the protection scope of the embodiments of this application should be determined by the protection scope of the claims.

Claims

1. A battery pack, characterized in that, The battery includes a water inlet and a water outlet, comprising: Multiple liquid cooling plates are provided at both ends of the liquid cooling plates along a first direction of the battery pack. The flow channel inlets are connected to the water inlet, and the flow channel outlets are connected to the water outlet. Along a second direction of the battery pack, the multiple liquid cooling plates are spaced apart, and the flow channel inlets of two adjacent liquid cooling plates are connected, and the flow channel outlets of two adjacent liquid cooling plates are connected. The first direction is the width direction of the battery pack; the second direction is the length direction of the battery pack. Multiple battery cells are provided, with one battery cell disposed between two adjacent liquid cooling plates, and the two sides of the battery cell along the second direction respectively contacting the adjacent liquid cooling plates; Wherein, along the second direction and in the direction away from the water inlet, the contact thermal resistance of at least two of the liquid cooling plates decreases sequentially.

2. The battery pack according to claim 1, characterized in that, The liquid cooling plate includes a plate body and a heat-conducting medium layer, wherein the heat-conducting medium layer is disposed on the surface of the plate body; The thickness of the thermally conductive medium layer of at least two of the liquid cooling plates decreases sequentially.

3. The battery pack according to claim 1 or 2, characterized in that, The liquid cooling plate includes a plate body and a heat-conducting medium layer, wherein the heat-conducting medium layer is disposed on the surface of the plate body; The thermal conductivity of the heat-conducting medium layer corresponding to at least two of the liquid cooling plates increases sequentially.

4. The battery pack according to any one of claims 1 to 3, characterized in that, The contact area between at least two of the liquid cooling plates and the corresponding battery cells increases sequentially.

5. The battery pack according to any one of claims 1 to 4, characterized in that, Along the second direction, the ratio of the maximum contact thermal resistance to the minimum contact thermal resistance of the liquid cooling plates at both ends of the battery pack is between 1 and 3.

6. The battery pack according to any one of claims 1 to 5, characterized in that, The liquid cooling plate includes multiple contact areas; Along the first direction, and in the direction away from the flow channel inlet, the contact thermal resistance of at least two of the contact areas decreases sequentially.

7. The battery pack according to claim 6, characterized in that, The liquid cooling plate includes a plate body and a heat-conducting medium layer, wherein the heat-conducting medium layer is disposed on the surface of the plate body; The thickness of the thermally conductive medium layer in at least two of the contact areas decreases sequentially.

8. The battery pack according to claim 6 or 7, characterized in that, The liquid cooling plate includes a plate body and a heat-conducting medium layer, wherein the heat-conducting medium layer is disposed on the surface of the plate body; The thermal conductivity of the thermally conductive medium layer in at least two of the contact areas increases sequentially.

9. The battery pack according to any one of claims 6 to 8, characterized in that, The contact area between at least two of the contact areas and the corresponding battery cells increases sequentially.

10. The battery pack according to any one of claims 6 to 9, characterized in that, Along the first direction, the ratio of the maximum contact thermal resistance to the minimum contact thermal resistance in the contact area at both ends of the liquid cooling plate is between 1 and 3.

11. The battery pack according to any one of claims 2, 3, 7 or 8, characterized in that, The thickness of the thermally conductive medium layer is less than or equal to 10 mm.

12. The battery pack according to any one of claims 1 to 11, characterized in that, The liquid cooling plate is provided with a flow channel, and along the first direction, the two ends of the flow channel are provided with the flow channel inlet and the flow channel outlet; The flow channel is either a serpentine flow channel or a straight flow channel, or a combination of both.

13. A liquid-cooled plate, characterized in that, include: The liquid cooling plate has a flow channel inlet and a flow channel outlet at both ends, and the side surface of the liquid cooling plate includes at least two contact areas. Along the direction away from the flow channel inlet, the contact thermal resistance of at least two of the contact areas decreases sequentially.

14. A battery pack, characterized in that, Includes multiple liquid cooling plates as described in claim 13 and multiple battery cells; Along the second direction of the battery pack, a plurality of liquid cooling plates are spaced apart, and a battery cell is disposed between two adjacent liquid cooling plates. The two sides of the battery cell along the second direction are respectively in contact with the contact area on the adjacent liquid cooling plate.

15. A thermal management system, characterized in that, The thermal management system includes a battery pack as described in any one of claims 1 to 12 or 14.

16. A means of transportation, characterized in that, The vehicle includes the thermal management system as described in claim 15.

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