Battery pack and electric device

Abstract

This application provides a battery pack and an electrical device, relating to the field of battery technology. The pack includes a housing, a battery module, and at least one set of heat exchange units. The housing includes a base plate; the battery module is disposed on the base plate and has a first surface; at least one set of heat exchange units are heat-exchange connected to the first surface of the battery module. Each heat exchange unit includes a first heat exchange tube and a second heat exchange tube arranged adjacent to each other and spaced apart along a first direction. The first and second heat exchange tubes are connected by at least one bent section. The heat exchange medium in the first and second heat exchange tubes flows in opposite directions. Along the first direction, each heat exchange unit has a first side surface and a second side surface facing away from each other, with a distance of B mm between the first and second side surfaces. The portion of the base plate located within the accommodating space has a dimension of D mm along the first direction, satisfying 0.042 ≤ B / D ≤ 0.283. This improves the overall heat exchange effect of the battery and enhances the temperature uniformity of the battery.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a battery pack and an electrical device. Background Technology

[0002] With the pursuit of higher energy density and faster charging / discharging speeds, battery performance is constantly improving. However, this also leads to a significant increase in the heat generated per unit time, resulting in a faster internal temperature rise and a greater risk of thermal runaway in overheated environments, thus posing safety concerns. In related technologies, battery heat exchange devices typically employ stamped and brazed liquid cooling plates. These plates usually consist of two layers of heat exchange plates forming a chamber with multiple spaced heat exchange channels. However, due to the large size of the heat exchange plates, it is difficult to precisely control the flatness of the surface in contact with the battery. This results in uneven heat dissipation, poor temperature uniformity, and consequently, reduced battery lifespan. Summary of the Invention

[0003] The purpose of this application is to provide a battery pack and power supply device to solve the technical problem of poor battery temperature uniformity in the prior art.

[0004] To achieve the above objectives, the technical solution adopted in this application is as follows: In a first aspect, this application provides a battery pack, including a housing, a battery module, and at least one set of heat exchange units. The housing has a receiving space and includes a base plate. The battery module is housed within the receiving space of the housing and is disposed on the base plate. The battery module has a first surface parallel to the base plate. At least one set of heat exchange units is heat-exchange connected to the first surface of the battery module. Each heat exchange unit includes a first heat exchange tube and a second heat exchange tube. The first and second heat exchange tubes are arranged at intervals along a first direction. The length direction of the first and second heat exchange tubes is perpendicular to the first direction. The first and second heat exchange tubes are connected by at least one bend. The heat exchange medium in the first and second heat exchange tubes flows in opposite directions. Along the first direction, the heat exchange unit has a first side and a second side facing away from each other. The distance between the first side and the second side is B mm. The portion of the base plate located within the receiving space has a dimension D mm along the first direction, satisfying: 0.042 ≤ B / D ≤ 0.283.

[0005] The above technical solution has at least the following beneficial technical effects: In the battery pack provided in this application embodiment, at least one set of heat exchange units is used to connect the battery module for heat exchange. Each heat exchange unit includes a first heat exchange pipe and a second heat exchange pipe connected by at least one bent section. The length directions of the first and second heat exchange pipes are perpendicular to a first direction, and the flow directions of the heat exchange medium within the first and second heat exchange pipes are opposite, which can improve the temperature uniformity of the battery module. Furthermore, the relationship between the distance Bmm between the first and second sides of the heat exchange unit and the dimension Dmm of the portion of the base plate located within the accommodating space along the first direction is controlled to satisfy: 0.042 ≤ B / D ≤ 0.283. When B / D < 0.042, the heat exchange medium flow path is longer, resulting in greater flow resistance and a slower flow rate. It also exchanges heat with more batteries, leading to a larger temperature difference between the heat exchange medium in the heat exchange pipe near the inlet and the heat exchange medium near the outlet. This results in a larger temperature difference across different areas of the battery module and poor temperature uniformity of the battery. When B / D > 0.283, the number of heat exchange units is small, which reduces the heat exchange efficiency of the battery. The poor heat exchange effect of the battery leads to a longer charging time, a larger overall internal resistance of the battery, and reduced battery safety.

[0006] Secondly, this application provides an electrical device including the battery pack described in the second aspect. Attached Figure Description

[0007] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art 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.

[0008] Figure 1 This is a three-dimensional structural diagram of the battery pack provided in the embodiments of this application.

[0009] Figure 2 This is a schematic diagram of the explosion and decomposition of the battery pack provided in the embodiment of this application.

[0010] Figure 3 This is a top view of the housing and heat exchanger tube assembly in the battery pack provided in the embodiments of this application.

[0011] Figure 4 This is a schematic diagram of the structure of the heat exchanger tube assembly in the battery pack provided in the embodiments of this application.

[0012] Figure 5 This is a schematic diagram of the structure of a heat exchanger tube assembly in a battery pack according to another embodiment of this application.

[0013] Figure 6This is a schematic diagram of the arrangement of the heat exchanger tube assembly and battery module in the battery pack provided in the embodiments of this application.

[0014] Figure 7 This is a cross-sectional view of the first heat exchanger tube or the second heat exchanger tube in the battery pack provided in the embodiments of this application.

[0015] In the diagram: 1-Battery module; 2-Heat exchanger tube assembly; 3-Box; 10-First surface; 11-Battery pack; 21-Heat exchange unit; 211-First heat exchanger tube; 212-Second heat exchanger tube; 213-First side; 214-Second side; 22-Bent section; 23-Inlet; 24-Outlet; 25-First side; 26-Second side; 31-Bottom plate; 32-Side plate; 111-Battery; 221-Circular arc section; 2110-Straight section; 2111-Bent arc section. Detailed Implementation

[0016] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0017] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0018] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0019] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0020] In related technologies, heat exchange tubes are used to replace liquid cooling plates to achieve heat exchange in the battery. Compared to liquid cooling plates, heat exchange tubes have higher forming efficiency, simpler manufacturing process, and better flatness, enabling uniform heat exchange with the battery. However, since there is no heat exchange plate in the heat exchange tubes, the temperature uniformity of the battery is poor. Therefore, adjacent heat exchange tubes need to be arranged close together to achieve more uniform heat dissipation. However, the applicant's research found that too densely arranged heat exchange tubes actually lengthen the flow path of the heat exchange medium in the heat exchange tubes, resulting in increased flow resistance and a deterioration in heat exchange effect.

[0021] Based on the above considerations, in order to solve the technical problems of poor battery temperature uniformity and heat exchange effect in the prior art, this application provides a battery pack and an electrical device.

[0022] The battery pack of this application is applicable to electrical devices that use batteries as a power source. The electrical devices disclosed in the embodiments of this application can be vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, power tools, energy storage devices, amusement equipment, elevators, and lifting equipment, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, or electric airplane toys, etc.; power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc.; energy storage devices can be energy storage walls, base station energy storage, container energy storage, etc.; amusement equipment can be carousels, drop towers, etc.

[0023] This application describes an electrical device using a vehicle as an example. The vehicle can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery is installed inside the vehicle, and the battery can be located at the bottom, front, or rear of the vehicle. The battery can be used to power the vehicle; for example, it can serve as the vehicle's operating power source. The vehicle may also include a controller and a motor. The controller controls the battery to supply power to the motor, for example, to meet the power needs of starting, navigation, and driving the vehicle. The battery can not only serve as the vehicle's operating power source but also as its driving power source, replacing or partially replacing gasoline or natural gas to provide driving power to the vehicle.

[0024] The technical solution of this application will now be described in detail with reference to the accompanying drawings.

[0025] Please refer to Figures 1 to 3This application provides a battery pack including a housing 3, a battery module 1, and at least one set of heat exchange units 21. The housing 3 has a receiving space and includes a bottom plate 31; the battery module 1 is received within the receiving space of the housing 3, and the battery module 1 is disposed on the bottom plate 31. The battery module 1 has a first surface 10, which is parallel to the bottom plate 31; at least one set of heat exchange units 21 is heat-exchange connected to the first surface 10 of the battery module 1. The heat exchange unit 21 includes a first heat exchange pipe 211 and a second heat exchange pipe 212, which are adjacent and spaced apart along a first direction X. The length direction is perpendicular to the first direction X. The first heat exchange tube 211 and the second heat exchange tube 212 are connected by at least one bend 22, and the heat exchange medium in the first heat exchange tube 211 and the second heat exchange tube 212 flows in opposite directions. Along the first direction X, the heat exchange unit 21 has a first side 213 and a second side 214 that are opposite to each other. The distance between the first side 213 and the second side 214 is B mm. The portion of the base plate 31 located in the accommodating space has a dimension D mm along the first direction X, which satisfies: 0.042≤B / D≤0.283.

[0026] It should be noted that the enclosure 3 refers to a closed or semi-closed structural component made of materials such as metal and plastic. It serves as the physical carrier for the battery module 1, BMS, heat exchange unit 21, and electrical connection components. It provides installation space for these components and, through a reasonable structural design, secures them within the enclosure 3, ensuring their relatively stable position during battery pack operation and preventing damage or loosening due to vibration, impact, or other factors. The design and manufacture of the enclosure 3 must meet the safety, reliability, and functionality requirements of the battery pack under different usage scenarios. The enclosure 3 generally consists of an upper enclosure and a lower enclosure. The lower enclosure 3 includes a base plate 31 and four side plates 32. The four side plates 32 are arranged around the outer circumferential edge of the base plate 31 and are integrally formed with the base plate 31, or they can be separately connected to the base plate 31. The upper enclosure is positioned opposite the base plate 31 so that the upper and lower enclosures together form a space for accommodating the battery module 1. The enclosure 3 can be cast from materials such as steel plate or aluminum alloy, or it can be made of high-strength materials, such as glass fiber reinforced composite materials or carbon fiber reinforced composite materials. The shape of the enclosure 3 can be cylindrical, cuboid, cube, etc.

[0027] The base plate 31 is the main load-bearing component of the battery pack, typically referring to the structural component installed at the bottom of the battery pack, used to support and fix the battery modules 1, battery management system, and heat exchange unit 21 inside the battery pack. The base plate 31 is located at the bottom of the side plate 32 and can be fixed to the bottom of the side plate 32 by methods such as welding, riveting, or screwing. The base plate 31 can be made of various materials, such as high-strength materials like aluminum alloy, steel, and stainless steel. The base plate 31 can be a rectangular, circular, or polygonal plate structure, with no specific limitation; its dimensions are determined by the number of batteries contained in the battery pack and the size of the batteries. A heat exchange medium is provided in the heat exchange unit 21. The heat exchange medium can be gas (air), liquid (such as water, alcohol, ethylene glycol / propylene glycol solution, refrigerant, oil, etc.) or solid (such as thermally conductive adhesive, thermally conductive solder paste, etc.).

[0028] The first surface 10 being parallel to the base plate 31 can be understood as either a surface parallel to and facing the base plate 31 (i.e., the bottom surface of the battery module 1) or a surface facing away from the base plate 31 (i.e., the top surface of the battery module 1). At least one set of heat exchange units 21 being heat-exchange connected to the first surface 10 of the battery module 1 can be understood as: at least one set of heat exchange units 21 can be in direct contact with the first surface 10 of the battery module 1 for heat exchange, or at least one set of heat exchange units 21 can be heat-exchange connected to the first surface 10 of the battery module 1 through thermally conductive adhesive or a heat spreader. It is understood that at least one set of heat exchange units 21 can be located between the base plate 31 and the battery module 1, or the base plate 31 can be located between the battery module 1 and at least one set of heat exchange units 21, as long as heat exchange between at least one set of heat exchange units 21 and the first surface 10 of the battery module 1 can be achieved.

[0029] It is understood that the first heat exchange tube 211 and the second heat exchange tube 212 form a heat exchange unit 21. The first heat exchange tube 211 and the second heat exchange tube 212 in the heat exchange unit 21 are arranged adjacent to each other and spaced apart along the first direction X. The flow directions of the heat exchange medium within the first heat exchange tube 211 and the second heat exchange tube 212 are opposite, and the first heat exchange tube 211 and the second heat exchange tube 212 are connected by at least one bend 22. Therefore, the first heat exchange tube 211 and the second heat exchange tube 212 can be directly connected through one bend 22, or indirectly connected through multiple bends 22. The bend 22 can be understood as a component that connects the two first heat exchange tubes 211 and the second heat exchange tube 212, causing the heat exchange medium within the first heat exchange tube 211 and the second heat exchange tube 212 to change direction. The first side 213 can be the side of the first heat exchange tube 211 away from the second heat exchange tube 212, and the second side 214 is the side of the second heat exchange tube 212 away from the first heat exchange tube 211.

[0030] The dimension of the portion of the base plate 31 located within the accommodating space along the first direction X can also be understood as the dimension of the orthographic projection area of ​​the accommodating space on the surface of the base plate 31 along the first direction X.

[0031] In the technical solution of this application embodiment, at least one set of heat exchange units 21 are used to connect with the battery module 1 for heat exchange. The heat exchange unit 21 includes a first heat exchange pipe 211 and a second heat exchange pipe 212 connected by at least one bent section 22. The length direction of the first heat exchange pipe 211 and the second heat exchange pipe 212 is perpendicular to the first direction X, and the flow direction of the heat exchange medium in the first heat exchange pipe 211 and the second heat exchange pipe 212 is opposite, thereby improving the temperature uniformity of the battery module 1. Moreover, the relationship between the distance Bmm between the first side 213 and the second side 214 of the heat exchange unit 21 and the dimension Dmm of the portion of the base plate 31 located in the accommodating space along the first direction X is controlled to satisfy: 0.042≤B / D≤0.283. For example, B / D can be 0.042, 0.053, 0.058, 0.073, 0.076, 0.090, 0.103, 0.105, 0.125, 0.137, 0.153, 0.167, 0.175, 0.177, 0.211, 0.237, 0.273, 0.283, etc., or any value between any two adjacent values ​​mentioned above. When B / D < 0.042, the heat exchange medium will have a longer flow path, resulting in higher flow resistance and slower flow velocity. It will also exchange heat with more batteries, leading to a larger temperature difference between the heat exchange medium near the inlet and near the outlet. This results in a larger temperature difference between different areas of battery module 1, and poor temperature uniformity of battery 111. When B / D > 0.283, the number of heat exchange units 21 is relatively small, reducing the battery's heat exchange efficiency and resulting in poor heat exchange performance. This leads to a longer battery pack charging time, higher overall battery internal resistance, and reduced battery safety. Therefore, it is necessary to comprehensively consider B and D, limiting B / D to the range of 0.042~0.283. This improves the overall heat exchange performance of the battery while reducing the temperature difference between different areas, improving temperature uniformity, and ultimately enhancing battery safety.

[0032] In some embodiments, B / D satisfies 0.073 ≤ B / D ≤ 0.177. For example, B / D can be 0.073, 0.076, 0.090, 0.103, 0.105, 0.125, 0.137, 0.153, 0.167, 0.175, 0.177, etc., or any value between any two adjacent values ​​mentioned above. This further improves the overall heat exchange effect of the battery, reduces the temperature difference between different areas of the battery, improves the temperature uniformity of the battery, and thus enhances the safety of battery use.

[0033] In some embodiments, the distance Bmm between the first side 213 and the second side 214 satisfies: 25mm ≤ Bmm ≤ 300mm. For example, Bmm can be 25.0mm, 30mm, 32.0mm, 45mm, 50.0mm, 54.0mm, 58.0mm, 65.0mm, 74.0mm, 80mm, 88.0mm, 95mm, 106.0mm, 115mm, 126.0mm, 136mm, 142.0mm, 150mm, 164.0mm, 170.0mm, 180mm, 190mm, 200mm, 210.0mm, 262.0mm, 300.0mm, etc., or any value between any two adjacent values ​​mentioned above.

[0034] By controlling the distance Bmm between the first side 213 and the second side 214 of the heat exchange unit 21 within the range of 25mm to 300mm, the heat exchange effect of the battery can be improved while reducing the temperature difference between the batteries 111, improving the temperature uniformity of the battery, and thus improving the safety of battery use. When Bmm < 25mm, that is, when the distance between the first side 213 of the first heat exchange tube 211 and the second side 214 of the second heat exchange tube 212 is too small, more heat exchange units 21 need to be arranged, resulting in a longer flow path for the heat exchange medium and a slower flow rate of the heat exchange medium, leading to a larger temperature difference between the batteries 111 in the battery module 1 and poor temperature uniformity of the battery. When Bmm > 300mm, that is, the distance between the first side 213 of the first heat exchange tube 211 and the second side 214 of the second heat exchange tube 212 is too large, then the number of heat exchange units 21 arranged is too small, which reduces the heat exchange efficiency of the battery, resulting in a poor heat exchange effect on the battery, which leads to a longer charging time for the battery pack and a larger overall internal resistance of the battery, thus reducing the safety of the battery.

[0035] In some embodiments, the dimension Dmm of the portion of the base plate 31 located within the accommodating space along the first direction X satisfies: 600mm ≤ Dmm ≤ 1800mm. For example, Dmm can be 600mm, 1200mm, 1800mm, etc., or any value between any two adjacent values ​​mentioned above.

[0036] By controlling the portion of the base plate 31 within the accommodating space, the dimension Dmm along the first direction X is within the range of 600mm to 1800mm. This improves the battery heat exchange effect while reducing the temperature difference between batteries 111, improving battery temperature uniformity, and thus enhancing battery safety. When Dmm < 600mm, meaning the dimension of the base plate 31 in the first direction X is too small, the number of heat exchange units 21 that can be arranged is too small, reducing the battery heat exchange efficiency and resulting in a poor heat exchange effect. This leads to a longer charging time for the battery pack, a larger overall internal resistance of the battery, and reduced battery safety. When Dmm > 1800mm, meaning the dimension of the portion of the base plate 31 within the accommodating space in the first direction X is too large, an excessive number of heat exchange units 21 need to be arranged. This results in a longer flow path for the heat exchange medium, a slower flow rate of the heat exchange medium, a larger temperature difference between batteries 111 in the battery module 1, and poor battery temperature uniformity.

[0037] In some embodiments, please refer to Figure 2 The battery module 1 includes multiple battery packs 11 arranged side by side along a first direction X. Each battery pack 11 includes multiple batteries 111 arranged sequentially along a second direction Y. The second direction Y is perpendicular to the first direction X and parallel to the length direction of the first heat exchange tube 211 and the second heat exchange tube 212. On the plane where the first surface 10 is located, the orthographic projection of a group of heat exchange units 21 overlaps with at least one battery pack 11.

[0038] In this context, the overlap between the orthographic projection of a group of heat exchange units 21 and at least one battery pack 11 on the plane containing the first surface 10 can be understood as each group of heat exchange units 21 being heat-exchange connected to at least one battery pack 11. This arrangement ensures that each battery pack 11 can be heat-exchange connected to a heat exchange unit 21, reducing the temperature rise between battery packs 11, improving temperature uniformity between battery packs 11, increasing the heat exchange efficiency of the battery pack 11, and thus improving the heat exchange effect of the battery pack.

[0039] In some embodiments, please refer to Figure 2 The battery 111 has a length direction, which is parallel to the first direction X. On the plane where the first surface 10 is located, the orthographic projections of the first heat exchange tube 211 and the second heat exchange tube 212 both overlap with the same battery pack 11.

[0040] It is understandable that the battery 111 has a length direction and a width direction. The length direction of the battery 111 is parallel to the first direction X, and the width direction of the battery 111 is parallel to the second direction Y. Thus, for each battery pack 11, more batteries 111 can be stacked along the second direction Y to increase the energy density of the battery. The fact that the orthographic projections of the first heat exchange tube 211 and the second heat exchange tube 212 both overlap with the same battery pack 11 can be understood as: the first heat exchange tube 211 and the second heat exchange tube 212 in each heat exchange unit 21 are simultaneously connected to the same battery pack 11 for heat exchange.

[0041] With the above settings, each battery pack 11 can exchange heat with the first heat exchange tube 211 and the second heat exchange tube 212 simultaneously, further reducing the temperature rise between battery packs 11, improving the temperature uniformity between battery packs 11, increasing the heat exchange efficiency of battery packs 11, and making the heat exchange effect of the entire battery pack better.

[0042] Of course, in some other embodiments, the length direction of the battery 111 may also be parallel to the second direction Y, and the width direction of the battery 111 may be parallel to the first direction X. On the plane where the first surface 10 is located, the orthographic projections of the first heat exchange tube 211 and the second heat exchange tube 212 both overlap with at least one battery pack 11. This allows each battery pack 11 to be heat-exchange connected to at least a portion of the heat exchange unit 21, reducing the temperature rise between battery packs 11, improving the heat exchange efficiency of the battery pack 11, and making the overall heat exchange effect of the battery pack better.

[0043] In some embodiments, please refer to Figure 6 When the length direction of the battery 111 is parallel to the first direction X, on the plane where the first surface 10 is located, the orthographic projection of at least one of the first heat exchange tube 211 and the second heat exchange tube 212 does not overlap with the center line of the orthographic projection of the battery pack 11 in the first direction X, wherein the center line of the orthographic projection of the battery pack 11 in the first direction X is parallel to the second direction Y.

[0044] It is understandable that at least one of the first heat exchange tube 211 and the second heat exchange tube 212 is positioned off-center from the centerline of the orthogonal projection of the battery pack 11 in the first direction X.

[0045] During battery cycling, the expansion and deformation of the battery 111 at its centerline relative to its sides is more significant. The above-mentioned design prevents the first heat exchange tube 211 or the second heat exchange tube 212 from being squeezed and deformed when located below the centerline of the battery pack 11 due to expansion and deformation at the centerline during cycling. This would affect heat exchange efficiency, leading to a larger temperature rise in the battery pack 11 and reducing the overall heat exchange effect. In this embodiment, the following condition can be further satisfied: 0.073 ≤ B / D ≤ 0.283. For example, B / D can be 0.073, 0.076, 0.090, 0.103, 0.105, 0.125, 0.137, 0.153, 0.167, 0.175, 0.177, 0.211, 0.218, 0.237, 0.250, 0.273, 0.283, etc., or any value between any two adjacent values ​​mentioned above. Furthermore, by appropriately increasing the value of B / D, the flow path of the heat exchange medium can be shortened, the flow rate of the heat exchange medium can be increased, and the temperature uniformity of the battery can be improved.

[0046] In some embodiments, when the length direction of the battery 111 is parallel to the first direction X, the orthographic projections of the first heat exchange tube 211 and the second heat exchange tube 212 on the plane where the first surface 10 is located do not overlap with the center line of the orthographic projection of the battery pack 11 in the first direction X. Furthermore, the first heat exchange tube 211 and the second heat exchange tube 212 are distributed on both sides of the center line of the orthographic projection of the battery pack 11 in the first direction X.

[0047] It is understood that the first heat exchange tube 211 and the second heat exchange tube 212 are distributed on both sides of the center line of the orthographic projection of the battery pack 11 in the first direction X. The first heat exchange tube 211 and the second heat exchange tube 212 can be arranged symmetrically about the center line of the orthographic projection of the battery pack 11 in the first direction X, or they can be arranged asymmetrically about the center line of the orthographic projection of the battery pack 11 in the first direction X.

[0048] With the above settings, it can be ensured that the first heat exchange tube 211 and the second heat exchange tube 212 will not be squeezed and deformed due to the obvious expansion and deformation at the center line of the battery pack 11. At the same time, it can balance the temperature of the battery pack 11 along the first direction X, so that the temperature of the battery pack 11 is uniform and the safety of the entire battery is improved.

[0049] In some embodiments, when the orthographic projections of the first heat exchange tube 211 and the second heat exchange tube 212 on the plane where the first surface 10 is located do not overlap with the center line of the orthographic projection of the battery pack 11 in the first direction X, and the first heat exchange tube 211 and the second heat exchange tube 212 are distributed on both sides of the center line of the orthographic projection of the battery pack 11 in the first direction X, the first heat exchange tube 211 and the second heat exchange tube 212 are spaced apart from the side of the battery pack 11, and the minimum distance between the first heat exchange tube 211 and the second heat exchange tube 212 and the side of the battery pack 11 is d1mm, which satisfies: 5mm≤d1mm≤150mm. For example, d1mm can be 5mm, 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, 50mm, 65mm, 75mm, 85mm, 95mm, 100mm, 110mm, 120mm, 130mm, 140mm, 150mm, etc., or it can be any value between any two adjacent values ​​mentioned above.

[0050] It is understandable that when the first heat exchanger 211 and the second heat exchanger 212 are distributed on both sides of the battery pack 11 along the first direction X, the first heat exchanger 211 and the second heat exchanger 212 are spaced apart from the sides of the battery pack 11. The minimum distance between the first heat exchanger 211 and the second heat exchanger 212 and the sides of the battery pack 11 can be understood as the distance between the first heat exchanger 211 and the second heat exchanger 212 and the nearest side of the battery pack 11.

[0051] With the above arrangement, the first heat exchange tube 211 and the second heat exchange tube 212 will not be too close to the side of the battery pack 11, thereby affecting the heat exchange effect at the center line of the battery pack 11. The first heat exchange tube 211 and the second heat exchange tube 212 are distributed on both sides of the center line of the battery pack 11 projected in the first direction X, and are spaced a certain distance from the side of the battery pack 11. This can make the heat exchange in the first direction X of the battery pack 11 uniform, improve the temperature uniformity of the battery pack 11, and thus improve the temperature uniformity of the entire battery.

[0052] In some embodiments, please refer to Figure 4 or Figure 5Along the first direction X, the distance between the first heat exchange tube 211 and the second heat exchange tube 212 is L2mm, satisfying: 15mm ≤ L2mm ≤ 200mm. For example, L2mm can be 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, 50mm, 65mm, 75mm, 85mm, 95mm, 100mm, 110mm, 120mm, 130mm, 140mm, 150mm, 160mm, 170mm, 180mm, 190mm, 200mm, etc., or any value between any two adjacent values ​​mentioned above. It can be understood that the distance L2mm between the first heat exchange tube 211 and the second heat exchange tube 212 refers to the distance between the two adjacent tube walls of the first heat exchange tube 211 and the second heat exchange tube 212.

[0053] By configuring the distance between the first heat exchange tube 211 and the second heat exchange tube 212 to be within the range of 15mm to 200mm, the heat exchange effect of the battery pack can be improved while reducing the temperature difference of the battery 111 and improving the temperature uniformity of the battery. When L2mm < 15mm, the distance between the first heat exchange tube 211 and the second heat exchange tube 212 is too small, and the temperature fields of the heat exchange medium inside the first heat exchange tube 211 and the second heat exchange tube 212 will overlap, causing heat exchange interference and thus affecting the heat exchange effect. When L2mm > 200mm, the distance between the first heat exchange tube 211 and the second heat exchange tube 212 is too large, which will result in a large temperature difference in the battery 111 and reduce the temperature uniformity of the battery.

[0054] In some embodiments, the width of the first heat exchange tube 211 or the second heat exchange tube 212 is C mm, satisfying: 5 mm ≤ C mm ≤ 50 mm. For example, C mm can be 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 50 mm, etc., or any value between any two adjacent values ​​mentioned above. It is understood that the widths of the first heat exchange tube 211 and the second heat exchange tube 212 can be the same or different, but the width C mm of both the first heat exchange tube 211 and the second heat exchange tube 212 must be within the range of 5 mm to 50 mm.

[0055] By controlling the width of the first heat exchange tube 211 and the second heat exchange tube 212 to be within the range of 5mm to 50mm, the overall heat exchange effect of the battery can be improved while reducing the temperature difference of the batteries 111 and improving the temperature uniformity of the battery. When Cmm < 5mm, the width of the first heat exchange tube 211 and the second heat exchange tube 212 is too small, the heat exchange area between a single heat exchange tube and the battery module 1 is too small, the heat exchange of the battery module 1 is uneven, and the temperature difference between different areas of the battery module 1 will be large, reducing the temperature uniformity of the battery. When Cmm > 50mm, the width of the first heat exchange tube 211 and the second heat exchange tube 212 is too large, which will reduce the flow rate of the heat exchange medium, affecting the heat exchange effect, and also resulting in a large temperature difference between the batteries 111 in the battery module 1, and poor temperature uniformity of the battery.

[0056] In some embodiments, please refer to Figure 4 or Figure 5 The bent segment 22 includes an arc segment 221, the inner radius of which is Rmm, satisfying: 7mm ≤ Rmm ≤ 200mm. For example, the inner radius Rmm of the arc segment 221 can be 7mm, 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, 50mm, 65mm, 75mm, 85mm, 95mm, 100mm, 110mm, 120mm, 130mm, 140mm, 150mm, 160mm, 170mm, 180mm, 190mm, 200mm, etc., or any value between any two adjacent values ​​mentioned above. This design ensures that the bent segment 22 is easy to form while preventing excessive temperature differences between the batteries 111. When the inner corner radius Rmm is less than 7mm, the bending section 22 is difficult to process and form, and the bending section 22 is prone to breakage. When the inner corner radius Rmm is greater than 200mm, the bending section 22 accounts for too large a proportion, resulting in poor heat exchange efficiency of the battery 111 at the bending section 22 compared to the battery 111 at other positions, and a large temperature difference between the batteries 111.

[0057] In some embodiments, please refer to Figure 6 The battery pack includes at least two heat exchange tube assemblies 2, each heat exchange tube assembly 2 is an integrally formed structure, each heat exchange tube assembly 2 includes an inlet 23, an outlet 24 and at least one set of heat exchange units 21, and at least two heat exchange tube assemblies 2 are arranged at intervals along the first direction X.

[0058] It is understood that the inlet 23, the outlet 24, and at least one set of heat exchange units 21 connected to the inlet 23 and the outlet 24 together constitute a heat exchange tube assembly 2, and the inlet 23 and the outlet 24 of at least two heat exchange tube assemblies 2 are connected by a manifold.

[0059] With the above configuration, each integrally formed heat exchange tube assembly 2 can reduce the flow resistance of the heat exchange medium and improve the heat exchange efficiency. Moreover, the arrangement of at least two heat exchange tube assemblies 2 at intervals along the first direction X allows the heat exchange medium to flow independently within each heat exchange tube assembly 2, appropriately shortening the flow path of the heat exchange medium and improving the temperature uniformity of the battery.

[0060] In some embodiments, when the battery pack includes at least two heat exchanger tube assemblies 2, each heat exchanger tube assembly 2 contains no more than four sets of heat exchange units 21. It is understood that each heat exchanger tube assembly 2 may include one, two, three, or four sets of heat exchange units 21. This arrangement avoids excessively long flow paths and slow flow rates of the heat exchange medium within each heat exchanger tube assembly 2, which could lead to large temperature differences between the batteries 111 in the battery module 1 and poor battery temperature uniformity.

[0061] In some embodiments, please refer to Figure 4 or Figure 5 The heat exchanger tube assembly 2 includes at least two sets of heat exchange units 21, with adjacent sets of heat exchange units 21 spaced apart. The distance between two adjacent sets of heat exchange units 21 is L1mm, satisfying the condition: 15mm ≤ L1mm ≤ 200mm. For example, L1mm can be 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, 50mm, 65mm, 75mm, 85mm, 95mm, 100mm, 110mm, 120mm, 130mm, 140mm, 150mm, 160mm, 170mm, 180mm, 190mm, 200mm, etc., or any value between any two adjacent values ​​mentioned above. By limiting the distance L1mm between two adjacent sets of heat exchange units 21 to the range of 15mm to 200mm, the heat exchange effect of the battery pack can be improved while reducing the temperature difference between the batteries 111, thus improving the battery temperature uniformity. When L1mm < 15mm, the spacing between two adjacent heat exchange units 21 is too small, and the temperature fields of the heat exchange medium between the heat exchange tubes will overlap, causing heat exchange interference and thus affecting the heat exchange effect. When L1mm > 200mm, the spacing between two adjacent heat exchange units 21 is too large, which will lead to a large temperature difference in the battery 111 and reduce the temperature uniformity of the battery.

[0062] In other embodiments, the heat exchange tube assembly 2 includes at least two sets of heat exchange units 21, with adjacent sets of heat exchange units 21 spaced apart. The distance between adjacent sets of heat exchange units 21 is L1mm, satisfying: L1mm≤Bmm. That is, the distance between adjacent sets of heat exchange units 21 is not greater than the distance between the first side 213 of the first heat exchange tube 211 and the second side 214 of the second heat exchange tube 212 in each heat exchange unit 21, thereby improving the overall heat exchange effect of the battery and improving the temperature uniformity of the battery.

[0063] In some embodiments, please refer to Figure 4 or Figure 5 The inlet 23 and outlet 24 of the heat exchanger tube assembly 2 are located on the same side of the heat exchanger tube assembly 2, and the inlet 23 is closer to the outer side of the heat exchanger tube assembly 2 than the outlet 24. This allows the inlet path of the heat exchange medium to be longer than the outlet path, improving the heat exchange efficiency of the battery and avoiding an excessively long outlet path of the heat exchange medium, which would affect the heat exchange effect.

[0064] In some embodiments, please refer to Figure 4 or Figure 5 The battery pack includes at least one heat exchange tube assembly 2, each heat exchange tube assembly 2 including an inlet 23, an outlet 24 and at least one set of heat exchange units 21, with the inlet 23 and outlet 24 located on the same side of the heat exchange tube assembly 2.

[0065] It is understood that the battery pack may include one, two, three, four, or even more heat exchanger tube assemblies 2, and the number of heat exchanger tube assemblies 2 can be arranged as needed. The inlet 23 and outlet 24 are located on the same side of the heat exchanger tube assembly 2, for example... Figure 4 or Figure 5 In the example shown, inlet 23 and outlet 24 are located on the same side of heat exchanger assembly 2 along its second direction Y. Alternatively, they could be located on the same side of heat exchanger assembly 2 along its first direction X. This arrangement improves heat exchange efficiency and reduces the number of current collectors, thereby lowering the risk of breakage and failure at the current collector connection and enhancing battery safety.

[0066] Of course, in some other embodiments, the inlet 23 and outlet 24 of each heat exchange tube assembly 2 may also be located on different sides of the heat exchange tube assembly 2 in order to arrange as many heat exchange units 21 or heat exchange tubes as possible and improve the heat exchange effect of the battery.

[0067] In some embodiments, please refer to Figure 5 The battery pack includes at least one heat exchange tube assembly 2. Each heat exchange tube assembly 2 includes an inlet 23, an outlet 24, and at least two sets of heat exchange units 21. The heat exchange tube assembly 2 includes a third side 25 and a fourth side 26 disposed opposite each other along a first direction X. The heat exchange tube assembly 2 is configured such that the heat exchange medium flows in from the inlet 23, passes sequentially along the first direction X from the third side 25 to the fourth side 26 through each set of heat exchange units 21, and then flows out from the outlet 24. Figure 5 The arrow direction is shown.

[0068] Understandably, in this embodiment, inlet 23 is connected to the first heat exchange tube 211 of heat exchange unit 21 located on the third side 25, and outlet 24 is connected to the second heat exchange tube 212 of heat exchange unit 21 located on the fourth side 26. This improves the heat exchange effect with the battery. In this embodiment, the distance Bmm between the first side 213 and the second side 214 of heat exchange unit 21 is further defined as: 30mm ≤ Bmm ≤ 300mm. For example, Bmm can be 30mm, 32.0mm, 45mm, 50.0mm, 54.0mm, 58.0mm, 65.0mm, 74.0mm, 80mm, 88.0mm, 95mm, 106.0mm, 115mm, 126.0mm, 136mm, 142.0mm, 150mm, 164.0mm, 170.0mm, 180mm, 190mm, 200mm, 210.0mm, 262.0mm, 300.0mm, etc., or any value between any two adjacent values ​​mentioned above. This setting prevents the distance between the first side 213 of the first heat exchange tube 211 and the second side 214 of the second heat exchange tube 212 from being too small, which would result in an excessively long flow path for the heat exchange medium, a slow flow rate, and poor temperature uniformity of the battery.

[0069] In other embodiments, please refer to Figure 4 The battery pack includes at least one heat exchange tube assembly 2. Each heat exchange tube assembly 2 includes an inlet 23, an outlet 24, and at least two sets of heat exchange units 21. Each heat exchange tube assembly 2 includes a third side 25 and a fourth side 26 arranged opposite each other along a first direction X. The heat exchange tube assembly 2 is configured such that the heat exchange medium flows from the inlet 23 into the first heat exchange tube 211 of the heat exchange unit 21 located on the third side 25, then into the heat exchange unit 21 located on the fourth side 26, and flows sequentially from the fourth side 26 to the third side 25 through each set of heat exchange units 21 along the first direction X, then through the second heat exchange tube 212 of the heat exchange unit 21 located on the third side 25, and then flows out through the outlet 24. The inlet 23 and the outlet 24 are respectively connected to the first heat exchange tube 211 and the second heat exchange tube 212 of the same heat exchange unit 21, and the outlet 23 and the inlet 24 are located on the same side of the heat exchange unit 21. Figure 4The arrows indicate the direction of the heat exchange. It is understood that in this embodiment, inlet 23 is connected to the first heat exchange tube 211 of the heat exchange unit 21 located on the third side 25, and outlet 24 is connected to the second heat exchange tube 212 of the heat exchange unit 21 located on the third side 25. This improves the heat exchange effect of the battery pack while reducing the temperature difference of the battery and improving the temperature uniformity of the battery. In this embodiment, it is further specified that: 0.065 ≤ B / D ≤ 0.283. For example, B / D can be 0.065, 0.070, 0.073, 0.076, 0.090, 0.103, 0.105, 0.125, 0.137, 0.153, 0.167, 0.175, 0.177, 0.211, 0.218, 0.237, 0.250, 0.273, 0.283, etc., or any value between any two adjacent values ​​mentioned above. By setting the above parameters, a larger B / D ratio can be achieved, preventing the heat exchange medium from having an excessively long flow path, which would result in a slower flow rate and poorer temperature uniformity of the battery. Of course, the heat exchange medium can also be configured according to... Figure 4 The flow is in the opposite direction of the arrow.

[0070] In some embodiments, please refer to Figure 6 The battery module 1 includes multiple batteries 111. On the plane where the first surface 10 is located, the orthographic projections of the first heat exchange tube 211 and the second heat exchange tube 212 both overlap with the same battery 111. It can be understood that the first heat exchange tube 211 and the second heat exchange tube 212 are both heat-exchange connected to the same battery 111.

[0071] The above settings improve the heat exchange efficiency of each battery 111, thereby improving the overall heat exchange efficiency of the battery, reducing the temperature difference between batteries 111, improving the temperature uniformity of the battery, and enhancing the safety of the battery.

[0072] In some embodiments, please refer to Figure 7 On a plane perpendicular to the length direction of the first heat exchange tube 211 or the second heat exchange tube 212, the cross-section of both the first heat exchange tube 211 and the second heat exchange tube 212 includes two oppositely arranged straight sections 2110, one of which is heat-exchange connected to the first surface 10. That is, on a longitudinal section perpendicular to the length direction of each heat exchange tube, the cross-section of the first heat exchange tube 211 or the second heat exchange tube 212 has two oppositely arranged straight sections 2110, which are used for heat-exchange connection with the first surface 10 of the battery module 1. This arrangement increases the heat exchange area between the first heat exchange tube 211 and the second heat exchange tube 212 and the battery module 1, thereby improving the battery's heat exchange efficiency.

[0073] In some embodiments, please refer to Figure 7The two straight sections 2110 arranged opposite each other are connected by a curved section 2111. The curved section 2111 can be arc-shaped, so that the two straight sections 2110 of the first heat exchange tube 211 or the second heat exchange tube 212 are connected by a smoothly transitioned curved section 2111. This can reduce the flow resistance of the heat exchange medium in the first heat exchange tube 211 and the second heat exchange tube 212, improve the uniformity of the flow velocity of the heat exchange medium, and thus improve the heat exchange efficiency.

[0074] Of course, in some other embodiments, the cross-section of the first heat exchange tube 211 or the second heat exchange tube 212 may also be square, trapezoidal or circular on a plane perpendicular to the length direction of the first heat exchange tube 211 or the second heat exchange tube 212.

[0075] In some embodiments, please refer to Figure 7 The wall thickness of the first heat exchange tube 211 or the second heat exchange tube 212 is emm, satisfying: 0.3mm≤emm≤2mm. For example, emm can be 0.3mm, 0.4mm, 0.6mm, 0.8mm, 1.0mm, 1.3mm, 1.5mm, 1.6mm, 1.8mm, 2.0mm, etc., or any value between any two adjacent values ​​mentioned above.

[0076] Through the above settings, the wall thickness e of the first heat exchange tube 211 or the second heat exchange tube 212 is controlled within the aforementioned range to ensure sufficient structural strength of the heat exchange tube, while improving heat exchange efficiency and overall battery safety. When emm < 0.3mm, the wall thickness of the first heat exchange tube 211 or the second heat exchange tube 212 is too small, resulting in poor strength and easy deformation under the pressure of the battery module 1. This reduces the flatness of the first heat exchange tube 211 or the second heat exchange tube 212, decreases the contact area between the first heat exchange tube 211 or the second heat exchange tube 212 and the battery module 1, and reduces heat exchange efficiency. When emm > 2mm, the wall thickness of the first heat exchange tube 211 or the second heat exchange tube 212 is too large, resulting in a small size of the heat exchange channel inside the heat exchange tube, a smaller flow rate of the heat exchange medium, poor heat exchange efficiency, a larger overall temperature rise rate of the battery, and reduced overall battery safety.

[0077] In some embodiments, the battery module 1 includes a plurality of batteries 111. On the plane where the first surface 10 is located, the ratio of the projected area of ​​all heat exchange units 21 on a battery 111 to the area of ​​the battery 111 on the first surface 10 is a, which satisfies: a≥6%, so that each battery 111 has sufficient heat exchange area, improves the heat exchange efficiency of a single battery 111, and reduces the temperature difference between batteries 111.

[0078] In some embodiments, along the width direction of the battery 111, when the thickness of the battery 111 is ≥30mm, the ratio of the projected area of ​​all heat exchange units 21 on a single battery 111 to the area of ​​the battery 111 on the first surface 10, along the plane of the first surface 10, is 'a', satisfying that a ≥ 15%. For example, a can be 15%, 20%, 30%, 40%, 50%, 60%, etc., or any value between any two adjacent values ​​mentioned above. In this embodiment, since the battery 111 is relatively thick, its capacity and heat generation are relatively large. Therefore, the ratio of the projected area of ​​all heat exchange units 21 on a single battery 111 to the area of ​​the battery 111 on the first surface 10, i.e., the proportion of the heat exchange area of ​​all heat exchange units 21 in a single battery 111, can be designed to be relatively large, thereby improving the heat exchange efficiency of the battery 111.

[0079] In some embodiments, along the width direction of the battery 111, when the thickness of the battery 111 is 30mm to 50mm, the ratio of the projected area of ​​all heat exchange units 21 on one battery 111 to the area of ​​the battery 111 on the first surface 10, along the plane of the first surface 10, is 'a', which satisfies: 15% ≤ a ≤ 40%. For example, a can be 15%, 20%, 30%, 40%, etc., or any value between any two adjacent values ​​mentioned above. This ensures that the thickness of the battery 111 is within the range of 30mm to 50mm, thereby improving the heat exchange efficiency of the battery 111.

[0080] In some embodiments, along the width direction of the battery 111, when the thickness of the battery 111 is ≥ 50 mm, the ratio of the projected area of ​​all heat exchange units 21 on one battery 111 to the area of ​​the battery 111 on the first surface 10, along the plane of the first surface 10, is 'a', which satisfies: a ≥ 40%. For example, a can be 40%, 50%, 60%, 70%, etc., or any value between any two adjacent values ​​mentioned above. This improves the heat exchange efficiency of the battery 111 when the thickness of the battery 111 is ≥ 50 mm.

[0081] It should be noted that battery 111 can store chemical energy and controllably convert it into electrical energy. In a recyclable battery, the active materials can be reactivated by charging after discharge, allowing for continued use. Battery 111 includes a casing and other functional components. The battery cell is the component in the battery that undergoes an electrochemical reaction with the electrolyte. The battery cell includes a positive electrode, a negative electrode, and a separator. During battery charging and discharging, the active materials repeatedly insert and extract between the positive and negative electrodes. The separator is disposed between the positive and negative electrodes, which can reduce short circuits between the positive and negative electrodes while allowing the passage of active material ions. In some embodiments, the positive electrode can be a positive electrode sheet, which may include a positive current collector and a positive active material disposed on at least one surface of the positive current collector. In some embodiments, the negative electrode can be a negative electrode sheet, which may include a negative current collector and a negative active material disposed on at least one surface of the negative current collector. In some embodiments, the separator is a membrane.

[0082] In some embodiments, the positive electrode active material is a layered metal oxide. The battery 111 has a capacity ≥ 50 Ah, and the distance Bmm between the first side 213 of the first heat exchange tube 211 and the second side 214 of the second heat exchange tube 212 is further defined as: 25mm ≤ Bmm ≤ 260mm. In this embodiment, the battery 111 generates a large amount of heat. To avoid excessively rapid temperature rise in the battery as a whole, the first heat exchange tube 211 and the second heat exchange tube 212 in the heat exchange unit 21 can be arranged relatively close together. That is, the distance Bmm between the first side 213 of the first heat exchange tube 211 and the second side 214 of the second heat exchange tube 212 is relatively small, limiting Bmm to the range of 25mm~260mm. This allows for the arrangement of a relatively large number of heat exchange units 21, thereby improving heat exchange efficiency and battery safety.

[0083] In some embodiments, when the capacity of battery 111 is ≥100Ah, it is further defined that: 25mm≤Bmm≤240mm. In this embodiment, the heat generated by battery 111 will be greater. In order to avoid the overall temperature rise of the battery being too fast, the first heat exchange tube 211 and the second heat exchange tube 212 in the heat exchange unit 21 can be arranged relatively closer. That is, the distance Bmm between the first side 213 of the first heat exchange tube 211 and the second side 214 of the second heat exchange tube 212 is further limited to the range of 25mm~240mm. In this way, a relatively large number of heat exchange units 21 can be arranged to improve heat exchange efficiency and improve battery safety.

[0084] In some embodiments, the heat exchange medium is a phase change heat exchange medium, which can be understood as a fluid that undergoes a phase change during the heat exchange process to absorb or release heat, such as a refrigerant. Therefore, compared to other heat exchange media, the phase change heat exchange medium has a higher heat exchange efficiency. In this embodiment, the wall thickness emm of the first heat exchange tube 211 or the second heat exchange tube 212 is further limited to: 0.5mm ≤ emm ≤ 2mm. By further limiting the wall thickness emm to the range of 0.5mm to 2mm, the structural strength of the first heat exchange tube 211 and the second heat exchange tube 212 can be improved, making them less susceptible to deformation by the battery module 1, thus affecting the heat exchange effect.

[0085] In some embodiments, the first heat exchange tube 211 and the second heat exchange tube 212 are made of aluminum alloy, which includes at least Al, Cu and Mn, wherein the mass percentage of Al is greater than or equal to 95wt%, and the sum of the mass percentages of Cu and Mn is 1wt% to 1.7wt%.

[0086] The above-mentioned design improves the corrosion resistance of the first heat exchange tube 211 and the second heat exchange tube 212, making them less susceptible to corrosion by the heat exchange medium or surrounding gases, thus increasing their strength and ultimately enhancing the overall safety of the battery. The testing method for elemental content in the aluminum alloy refers to GB / T7999-2015, "Direct-reading photoelectric emission spectrometry analysis method for aluminum and aluminum alloys".

[0087] In some other embodiments, the first heat exchange tube 211 and the second heat exchange tube 212 are made of stainless steel, which includes Cr, wherein the mass percentage of Cr is 15wt%~23wt%.

[0088] The above-mentioned design improves the corrosion resistance of the first heat exchange tube 211 and the second heat exchange tube 212, making them less susceptible to corrosion by the heat exchange medium or surrounding gas, thus increasing their strength and overall battery safety. The testing method for elemental content in stainless steel refers to GB / T11170-2008, "Determination of Multi-Element Content in Stainless Steel - Spark Discharge Atomic Emission Spectrometry (Conventional Method)".

[0089] The battery pack provided in this application will be described in detail below through specific embodiments.

[0090] It should be noted that this application can use measuring instruments such as micrometers or calipers to measure parameters such as length, width, distance, thickness, and wall thickness.

[0091] Preparation of Battery 111: (1) Preparation of the positive electrode: The prepared positive electrode active material, conductive agent (e.g., acetylene black), and binder (e.g., PVDF) are mixed, and solvent NMP is added. The mixture is stirred under vacuum until the system is homogeneous to obtain a positive electrode slurry. The positive electrode slurry is uniformly coated on both surfaces of the positive electrode current collector foil, dried at room temperature, and then transferred to an oven for further drying. The positive electrode sheet is then obtained by rolling and slitting.

[0092] Specifically, the mass ratio of positive electrode active material: conductive agent: binder satisfies (92~98): (4~1): (4~1).

[0093] (2) Preparation of negative electrode: The negative electrode active material, conductive agent (e.g., acetylene black), thickener (e.g., carboxymethyl cellulose (CMC)), and binder (e.g., styrene-butadiene rubber (SBR)) are mixed, and deionized water is added as a solvent. The mixture is stirred under vacuum until the system is homogeneous to obtain a negative electrode slurry. The negative electrode slurry is uniformly coated on both surfaces of the negative electrode current collector foil, air-dried at room temperature, and then transferred to an oven for further drying. Finally, the negative electrode sheet is obtained by rolling and slitting.

[0094] Specifically, the ratio of negative electrode active material: conductive agent: thickener: binder satisfies (90~96): (4~2): (2~1): (4~1).

[0095] (3) Preparation of electrolyte: Ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) were mixed in a volume ratio of 1:1:1 to obtain an organic solvent. Then, fully dried lithium salt LiPF6 was dissolved in the mixed organic solvent to prepare an electrolyte with a concentration of 1 mol / L.

[0096] (4) Preparation of the diaphragm: Polyethylene film is selected as the diaphragm.

[0097] (5) Preparation of lithium-ion batteries: The positive electrode, separator, and negative electrode are stacked in sequence and formed into a bare cell by winding or stacking. The bare cell is then placed in a battery casing, which is a prismatic casing. The battery is dried, injected with electrolyte, and then packaged, allowed to stand, formed, and calibrated to obtain a lithium-ion battery.

[0098] In the selection of materials for the battery, this application may also select other materials, not limited to the materials limited by the above preparation method. The positive electrode active material may be selected from one or more lithium-containing positive electrode active materials, including lithium iron phosphate, ternary materials containing nickel, cobalt and manganese, and lithium manganese iron phosphate; the negative electrode active material may be selected from one or more negative electrode active main materials, such as artificial graphite, natural graphite, silicon carbide, silicon oxide, and lithium titanate.

[0099] The conductive agent includes, but is not limited to, one or more combinations of graphite, superconducting carbon, carbon black (such as acetylene black, Ketjen black, Super P, etc.), carbon nanotubes, graphene, and carbon nanofibers.

[0100] The adhesive includes, but is not limited to, one or more combinations of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, fluorinated acrylate resin, styrene-butadiene rubber, polyacrylic acid, sodium polyacrylate, polyacrylamide, polyvinyl alcohol, sodium alginate, polymethacrylic acid, carboxymethyl chitosan, etc.

[0101] The solvent can be deionized water, NMP (N-methylpyrrolidone), alcohol, ether, ketone or other types of pyrrolidone, etc.

[0102] The positive electrode current collector foil can be a metal foil or a composite current collector. For example, as a metal foil, it can be made of stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium with a silver-plated surface. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.). The negative electrode current collector foil can be a metal foil or a composite current collector. The metal foil can be made of stainless steel, copper, aluminum, nickel, carbon electrodes, or titanium with a silver-plated surface. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, copper, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0103] Performance tests are as follows: Performance Test 1: Temperature difference of batteries in the battery pack.

[0104] For each embodiment and comparative example, a corresponding heat exchange unit 21 is prepared. Identical battery pack housings 3 are prepared, and the heat exchange unit 21 is fixed to the base plate 31 of the battery pack housing 3. Following the battery 111 preparation method described above, corresponding batteries 111 are manufactured. In the embodiments and comparative examples, for the same size base plate 31, the same number and arrangement of batteries 111 are used and arranged inside the battery pack. At least some of the bottom surfaces of the batteries are heat-exchange connected to the first heat exchange tube 211 and the second heat exchange tube 212 in the heat exchange unit 21. A temperature sensor is installed at the same position on the top of the battery that is heat-exchange connected to the heat exchange unit 21 to measure the battery temperature in real time. Ethylene glycol aqueous solution is used as the heat exchange medium in the heat exchange tubes.

[0105] At room temperature (20℃), the battery pack is charged at a constant current rate of 2C until the battery voltage reaches its upper limit. Then, constant voltage charging is switched until the battery current drops to 0.05C. The temperature difference between the highest and lowest temperatures of the batteries at any given time is recorded as the battery temperature difference within the battery pack. A battery temperature difference of 3℃ or less is considered good; a temperature difference of 5℃ or less but greater than 3℃ is considered acceptable; a temperature difference greater than 5℃ is considered unacceptable.

[0106] Different systems require corresponding adjustments to their upper and lower voltage limits: Lithium iron phosphate (LFP) - upper limit 3.65V, lower limit 2.5V; Nickel-cobalt-manganese ternary NCM - upper limit 4.25V, lower limit 2.5V; Lithium manganese iron phosphate (LFMP) - upper limit 4.25V, lower limit 2.5V; Lithium nickel manganese oxide - upper limit 4.8V, lower limit 3.5V.

[0107] The positive electrode active material used in this test was selected from LiNi. 0.6 Co 0.2 Mn 0.2 Taking O2 as an example, other positive electrode materials all meet the above test requirements, and the mass ratio of positive electrode active material: conductive agent: binder meets 96:2:2; the negative electrode active material is selected from artificial graphite, and the ratio of negative electrode active material: conductive agent: thickener: binder meets 95:2:1:2.

[0108] Performance Test 2: Battery Pack Fast Charging Time.

[0109] For each embodiment and comparative example, a corresponding heat exchange unit 21 is prepared. Identical battery pack housings 3 are prepared, and the heat exchange unit 21 is fixed to the base plate 31 of the battery pack housing 3. The corresponding batteries are manufactured according to the battery manufacturing method described above. In the embodiments and comparative examples, for base plates of the same size, the same number and arrangement of batteries 111 are used and arranged inside the battery pack. At least some of the bottom surfaces of the batteries are heat-exchange connected to the first heat exchange tube 211 and the second heat exchange tube 212 in the heat exchange unit 21. Ethylene glycol aqueous solution is used as the heat exchange medium in the heat exchange tubes.

[0110] After pre-capacitating the batteries in the battery pack, discharge them to the lower limit voltage at a 1C rate. After standing at room temperature (20℃) for 30 minutes, charge at 0.33C to 10% SOC, then charge the battery pack at a 4C rate for 15 minutes, and then measure the battery charge. If the battery pack charge is less than 80% SOC, the fast charging time is considered unqualified; if the battery pack charge is less than 85% SOC but greater than or equal to 80% SOC, the fast charging time is considered qualified; if the battery pack charge is greater than or equal to 85% SOC, the fast charging time is considered good.

[0111] Different types of prismatic batteries require corresponding adjustments to their upper and lower voltage limits: LFP (LiFePO4, lithium iron phosphate) - upper limit 3.65V, lower limit 2.5V; NCM (lithium nickel cobalt manganese oxide) - upper limit 4.25V, lower limit 2.5V; LFMP (lithium manganese iron phosphate) - upper limit 4.25V, lower limit 2.5V; lithium nickel manganese oxide - upper limit 4.8V, lower limit 3.5V.

[0112] The positive electrode active material used in this test was selected from LiNi. 0.6 Co 0.2 Mn 0.2 Taking O2 as an example, all other positive electrode materials meet the above test requirements, with the mass ratio of positive active material: conductive agent: binder meeting 96:2:2; the negative active material is selected from artificial graphite, and the ratio of negative active material: conductive agent: thickener: binder meets 95:2:1:2. The test results are shown in Table 1.

[0113] Table 1. Test parameters and results of Examples 1 to 25 and Comparative Examples 1 to 6 As shown in Table 1 above, compared to Comparative Examples 1 to 6, in Examples 1 to 25, when B / D satisfies 0.042≤B / D≤0.283, performance 1 is considered acceptable or good. That is, in the battery packs of Examples 1 to 25, the battery temperature difference is less than or equal to 5℃. Performance 2 is characterized by an acceptable or good fast charging time for the battery pack. That is, in the battery packs of Examples 1 to 25, after being left to stand at room temperature (20℃) for 30 minutes, charged at 0.33C to 10% SOC, and then charged at 4C for 15 minutes, the battery pack's capacity is greater than or equal to 80% SOC.

[0114] In Comparative Example 1, the Bmm value is less than 25mm, resulting in a B / D ratio of less than 0.042. The excessively small B / D value leads to a longer heat exchange medium flow path, a slower flow rate of the heat exchange medium, poor temperature uniformity of the battery, and a battery temperature difference greater than 5℃ in the battery pack. Therefore, Performance 1 is considered unqualified.

[0115] In Comparative Example 2, although the Bmm value is within the range of 25mm~300mm, the Bmm value is too large, resulting in a B / D greater than 0.283. The number of heat exchange units 21 arranged is small, resulting in poor heat exchange effect of the battery and long fast charging time of the battery pack. After standing at room temperature (20℃) for 30 minutes, the battery pack is charged at 0.33C to 10% SOC, and then charged at 4C rate for 15 minutes. The battery pack capacity is less than 80% SOC. Therefore, performance 2 is unqualified.

[0116] In Comparative Example 3, the B / D value is less than 0.042, resulting in a longer heat exchange medium flow path, slower heat exchange medium flow rate, poor battery temperature uniformity, and a battery temperature difference greater than 5℃ in the battery pack. Performance 1 is unqualified.

[0117] In Comparative Example 4, the Bmm value is greater than 300mm, resulting in a B / D value greater than 0.283. The number of heat exchange units is relatively small, leading to poor heat exchange performance of the battery and a long fast charging time for the battery pack. After standing at room temperature (20℃) for 30 minutes, the battery pack is charged at 0.33C to 10% SOC, and then charged at 4C for 15 minutes. The battery pack's capacity is less than 80% SOC. Therefore, performance 2 is unqualified.

[0118] Although the Dmm value in Comparative Example 5 is within the range of 600mm~1800mm, the Dmm value is too large, resulting in a B / D value of less than 0.042. This leads to poor temperature uniformity of the battery, with a temperature difference of more than 5℃ between batteries in the battery pack, and performance 1 is unqualified.

[0119] In Comparative Example 6, the Bmm value is greater than 300mm, resulting in a B / D ratio greater than 0.283. The excessively large B / D value leads to poor heat exchange in the battery and a longer fast charging time. After being left to stand at room temperature (20℃) for 30 minutes, the battery pack is charged at 0.33C to 10% SOC, and then charged at 4C for 15 minutes. The battery pack's capacity is less than 80% SOC. Therefore, performance 2 is unqualified.

[0120] Compared to Examples 3 and 4, Examples 1 and 2, while having the same Dmm value, have smaller Bmm values, even though they are within the range of 25mm to 300mm. This results in a smaller B / D value, even though it is within the range of 0.042 to 0.283. Consequently, the temperature uniformity of the batteries in Examples 1 and 2 is worse than that in Examples 3 and 4, with a battery temperature difference of less than or equal to 5°C and greater than 3°C, indicating that performance 1 is qualified. In contrast, the battery temperature difference in Examples 3 and 4 is less than or equal to 3°C, indicating that performance 1 is good.

[0121] Compared to Examples 3 and 4, Examples 5 and 6, while having the same Dmm value, have larger Bmm values ​​(both within the range of 25mm to 300mm), resulting in a larger B / D ratio. This leads to longer fast-charging times for the battery packs in Examples 5 and 6. After being left to stand at room temperature (20°C) for 30 minutes, the battery pack is charged at 0.33C to 10% SOC, and then charged at 4C for 15 minutes. The battery pack's charge is less than 85% SOC but greater than or equal to 80% SOC, and performance 2 is considered acceptable. In contrast, in Examples 3 and 4, after being left to stand at room temperature (20°C) for 30 minutes, the battery pack is charged at 0.33C to 10% SOC, and then charged at 4C for 15 minutes. The battery pack's charge is greater than or equal to 85% SOC, and performance 2 is considered good.

[0122] Compared to Examples 11 to 14, Examples 7 to 10, under the same Dmm value, although the B / D value in Examples 7 to 10 is in the range of 0.042 to 0.283, the B / D value is smaller. Therefore, the temperature uniformity of the batteries in Examples 7 to 10 is worse than that in Examples 11 to 14. The battery temperature difference in the battery pack is less than or equal to 5°C and greater than 3°C, and performance 1 is qualified. In contrast, the battery temperature difference in Examples 11 to 14 is less than or equal to 3°C, and performance 1 is good.

[0123] Compared to Examples 11 to 14, Examples 15 and 16 have larger B / D values ​​while maintaining the same Dmm value. This results in longer fast charging times for the battery packs in Examples 15 and 16. After being left to stand at room temperature (20°C) for 30 minutes, the battery pack is charged at 0.33C to 10% SOC, and then charged at 4C for 15 minutes. The battery pack's charge is less than 85% SOC, but greater than or equal to 80% SOC, and performance 2 is considered acceptable. In contrast, in Examples 11 to 14, after being left to stand at room temperature (20°C) for 30 minutes, the battery pack is charged at 0.33C to 10% SOC, and then charged at 4C for 15 minutes. The battery pack's charge is greater than or equal to 85% SOC, and performance 2 is considered good.

[0124] Compared to Examples 19 to 23, Examples 17 and 18 have smaller B / D values ​​while maintaining the same Dmm value. Therefore, the temperature uniformity of the batteries in Examples 17 and 18 is worse than that in Examples 19 to 23, with battery temperature differences in the battery pack being less than or equal to 5°C and greater than 3°C. Performance 1 is considered acceptable. In contrast, the battery temperature differences in Examples 19 to 23 are all less than or equal to 3°C, and performance 1 is considered good.

[0125] Compared to Examples 11 to 14, Example 24, with the same Dmm value, has a Bmm value greater than 300mm. This excessively large Bmm value results in a B / D value that, although within the range of 0.042 to 0.283, is too high. This leads to a longer fast-charging time for the battery pack in Example 24. After being left to stand at room temperature (20°C) for 30 minutes, it is charged at 0.33C to 10% SOC, and then charged at 4C for 15 minutes. The battery pack's charge is less than 85% SOC, but greater than or equal to 80% SOC, and performance 2 is considered acceptable. In contrast, in Examples 11 to 14, after being left to stand at room temperature (20°C) for 30 minutes, it is charged at 0.33C to 10% SOC, and then charged at 4C for 15 minutes, the battery pack's charge is greater than or equal to 85% SOC, and performance 2 is considered good.

[0126] Compared to Examples 19 to 23, Example 25, with the same Dmm value, has a Bmm value greater than 300mm. This excessively large Bmm value results in a B / D value that, although within the range of 0.042 to 0.283, is still relatively large. This leads to a longer fast-charging time for the battery pack in Example 25. After being left to stand at room temperature (20°C) for 30 minutes, it is charged at 0.33C to 10% SOC, and then charged at 4C for 15 minutes. The battery pack's charge is less than 85% SOC, but greater than or equal to 80% SOC, and performance 2 is considered acceptable. In contrast, in Examples 19 to 23, after being left to stand at room temperature (20°C) for 30 minutes, it is charged at 0.33C to 10% SOC, and then charged at 4C for 15 minutes, the battery pack's charge is greater than or equal to 85% SOC, and performance 2 is considered good.

[0127] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A battery pack, characterized by, include: The box (3) has a receiving space, and the box (3) includes a bottom plate (31). A battery module (1) is housed in the housing space of the housing (3). The battery module (1) is disposed on the base plate (31). The battery module (1) has a first surface (10) that is parallel to the base plate (31). At least one set of heat exchange units (21) is heat-exchange connected to the first surface (10) of the battery module (1). The heat exchange unit (21) includes a first heat exchange tube (211) and a second heat exchange tube (212). The first heat exchange tube (211) and the second heat exchange tube (212) are arranged adjacent to each other and spaced apart along a first direction (X). The length direction of the first heat exchange tube (211) and the second heat exchange tube (212) is perpendicular to the first direction (X). The first heat exchange tube (211) and the second heat exchange tube (212) are connected by at least one The two bends (22) are connected, and the heat exchange medium in the first heat exchange tube (211) and the second heat exchange tube (212) flows in opposite directions. Along the first direction (X), the heat exchange unit (21) has a first side (213) and a second side (214) that are opposite to each other. The distance between the first side (213) and the second side (214) is B mm. The portion of the base plate (31) located in the accommodating space has a dimension of D mm along the first direction (X), satisfying: 0.042≤B / D≤0.

283.

2. The battery pack according to claim 1, characterized in that, The battery module (1) includes multiple battery packs (11) arranged side by side along the first direction (X). Each battery pack (11) includes multiple batteries (111) arranged sequentially along the second direction (Y). The second direction (Y) is perpendicular to the first direction (X) and parallel to the length direction of the first heat exchange tube (211) and the second heat exchange tube (212). On the plane where the first surface (10) is located, the orthographic projection of a group of heat exchange units (21) overlaps with at least one battery pack (11).

3. The battery pack according to claim 2, characterized in that, The battery (111) has a length direction, which is parallel to the first direction (X). On the plane where the first surface (10) is located, the orthographic projections of the first heat exchange tube (211) and the second heat exchange tube (212) overlap with the same battery pack (11).

4. The battery pack according to claim 3, characterized in that, On the plane where the first surface (10) is located, the orthographic projection of at least one of the first heat exchange tube (211) and the second heat exchange tube (212) does not overlap with the center line of the orthographic projection of the battery pack (11) in the first direction (X), wherein the center line of the orthographic projection of the battery pack (11) in the first direction (X) is parallel to the second direction (Y).

5. The battery pack according to claim 4, characterized in that, The following condition must be met: 0.073≤B / D≤0.

283.

6. The battery pack according to claim 4, characterized in that, On the plane where the first surface (10) is located, the orthographic projections of the first heat exchange tube (211) and the second heat exchange tube (212) do not overlap with the center line of the orthographic projection of the battery pack (11) in the first direction (X), and the first heat exchange tube (211) and the second heat exchange tube (212) are distributed on both sides of the center line of the orthographic projection of the battery pack (11) in the first direction (X).

7. The battery pack according to claim 6, characterized in that, Along the first direction (X), the first heat exchange tube (211) and the second heat exchange tube (212) are both spaced apart from the side of the battery pack (11). The minimum distance between the first heat exchange tube (211) and the second heat exchange tube (212) and the side of the battery pack (11) is d1mm, which satisfies: 5mm≤d1mm≤150mm.

8. The battery pack according to claim 1, characterized in that, Along the first direction (X), the distance between the first heat exchange tube (211) and the second heat exchange tube (212) is L2mm, satisfying: 15mm≤L2mm≤200mm; and / or, The width of the first heat exchange tube (211) or the second heat exchange tube (212) is C mm, satisfying: 5 mm ≤ C mm ≤ 50 mm.

9. The battery pack according to claim 1, characterized in that, The bent segment (22) includes an arc segment (221), the inner radius of the arc segment (221) is Rmm, which satisfies: 7mm≤Rmm≤200mm.

10. The battery pack according to any one of claims 1 to 9, characterized in that, The battery pack includes at least two heat exchange tube assemblies (2), each of which is an integrally formed structure. The heat exchange tube assembly (2) includes an inlet (23), an outlet (24), and at least one set of heat exchange units (21). At least two heat exchange tube assemblies (2) are arranged at intervals along the first direction (X).

11. The battery pack according to claim 10, characterized in that, Each heat exchange tube assembly (2) contains no more than 4 sets of heat exchange units (21).

12. The battery pack according to claim 10, characterized in that, The heat exchange tube assembly (2) includes at least two sets of heat exchange units (21), with adjacent sets of heat exchange units (21) spaced apart. Along the first direction (X), the distance between adjacent sets of heat exchange units (21) is L1mm, satisfying: 15mm≤L1mm≤200mm.

13. The battery pack according to claim 10, characterized in that, The heat exchange tube assembly (2) includes at least two sets of heat exchange units (21), with two adjacent sets of heat exchange units (21) spaced apart, and the distance between two adjacent sets of heat exchange units (21) is L1mm, satisfying: L1≤B.

14. The battery pack according to claim 10, characterized in that, The inlet (23) and outlet (24) of the heat exchange tube assembly (2) are located on the same side of the heat exchange tube assembly (2), and the inlet (23) is closer to the outside of the heat exchange tube assembly (2) than the outlet (24).

15. The battery pack according to any one of claims 1 to 9, characterized in that, The battery pack includes at least one heat exchange tube assembly (2), all of which are integrally formed structures. The heat exchange tube assembly (2) includes an inlet (23), an outlet (24) and at least one set of heat exchange units (21). The inlet (23) and the outlet (24) are located on the same side of the heat exchange tube assembly (2).

16. The battery pack according to any one of claims 1 to 9, characterized in that, The battery pack includes at least one heat exchange tube assembly (2), the heat exchange tube assembly (2) includes an inlet (23), an outlet (24) and at least two sets of heat exchange units (21), the heat exchange tube assembly (2) includes a third side (25) and a fourth side (26) disposed opposite each other along the first direction (X), the heat exchange tube assembly (2) is configured to allow heat exchange medium to flow in from the inlet (23), and flow out from the outlet (24) after passing sequentially from the third side (25) to the fourth side (26) along the first direction (X) through each set of heat exchange units (21).

17. The battery pack according to claim 16, characterized in that, The following conditions must be met: 30mm≤Bmm≤300mm.

18. The battery pack according to any one of claims 1 to 9, characterized in that, The battery pack includes at least one heat exchange tube assembly (2), the heat exchange tube assembly (2) includes an inlet (23), an outlet (24) and at least two sets of heat exchange units (21), the heat exchange tube assembly (2) includes a third side (25) and a fourth side (26) arranged opposite each other along the first direction (X), the heat exchange tube assembly (2) is configured such that the heat exchange medium flows from the inlet (23) into the first heat exchange tube (211) of the heat exchange unit (21) located on the third side (25) and then into the heat exchange unit (21) located on the fourth side (26). And along the first direction (X), from the fourth side (26) to the third side (25), it passes through each group of heat exchange units (21) in sequence, and then flows out through the outlet (24) after passing through the second heat exchange tube (212) of the heat exchange unit (21) located on the third side (25). The inlet (23) and the outlet (24) are respectively connected to the first heat exchange tube (211) and the second heat exchange tube (212) of the same heat exchange unit (21), and the outlet (23) and the inlet (24) are located on the same side of the heat exchange unit (21).

19. The battery pack according to claim 18, characterized in that, The following condition must be met: 0.065≤B / D≤0.

283.

20. The battery pack according to any one of claims 1 to 9, characterized in that, The battery module (1) includes multiple batteries (111). On the plane where the first surface (10) is located, the orthographic projections of the first heat exchange tube (211) and the second heat exchange tube (212) overlap with the same battery (111).

21. The battery pack according to any one of claims 1 to 9, characterized in that, On a plane perpendicular to the length direction of the first heat exchange tube (211) or the second heat exchange tube (212), the cross-section of the first heat exchange tube (211) and the second heat exchange tube (212) each includes two oppositely arranged straight sections (2110), and one of the straight sections (2110) is heat-exchange connected to the first surface (10).

22. The battery pack according to claim 21, characterized in that, The two straight segments (2110) that are set opposite to each other are connected by a curved segment (2111).

23. The battery pack according to any one of claims 1 to 9, characterized in that, The wall thickness of the first heat exchange tube (211) or the second heat exchange tube (212) is emm, which satisfies: 0.3mm≤emm≤2mm.

24. The battery pack according to any one of claims 1 to 9, characterized in that, The battery module (1) includes multiple batteries (111). On the plane where the first surface (10) is located, the ratio of the orthogonal projection area of ​​all the heat exchange units (21) on one of the batteries (111) to the area of ​​the battery (111) on the first surface (10) is a, which satisfies: a≥6%.

25. The battery pack according to any one of claims 1 to 9, characterized in that, The battery module (1) includes multiple batteries (111), the thickness of the battery (111) is ≥30mm, and on the plane where the first surface (10) is located, the ratio of the orthogonal projection area of ​​all the heat exchange units (21) on one battery (111) to the area of ​​the battery (111) on the first surface (10) is a, which satisfies: a≥15%.

26. The battery pack according to claim 25, characterized in that, The thickness of the battery (111) is 30mm~50mm. On the plane where the first surface (10) is located, the ratio of the orthogonal projection area of ​​all the heat exchange units (21) on one battery (111) to the area of ​​the battery (111) on the first surface (10) is a, which satisfies: 15%≤a≤40%.

27. The battery pack according to claim 25, characterized in that, The thickness of the battery (111) is ≥50mm. On the plane where the first surface (10) is located, the ratio of the orthogonal projection area of ​​all the heat exchange units (21) on one battery (111) to the area of ​​the battery (111) on the first surface (10) is a, which satisfies: a≥40%.

28. The battery pack according to any one of claims 1 to 9, characterized in that, The battery module (1) includes multiple batteries (111), each battery (111) includes a cell, each cell includes a positive electrode sheet, the positive electrode sheet includes a positive electrode active material, the positive electrode active material is a layered metal oxide, the capacity of the battery (111) is ≥50Ah, and satisfies: 25mm≤Bmm≤260mm.

29. The battery pack according to claim 28, characterized in that, The capacity of the battery (111) is ≥100Ah, and satisfies: 25mm≤Bmm≤240mm.

30. The battery according to any one of claims 1 to 9, characterized in that, The heat exchange medium is a phase change heat exchange medium, and the wall thickness emm of the first heat exchange tube (211) or the second heat exchange tube (212) satisfies: 0.5mm≤emm≤2mm.

31. The battery pack according to any one of claims 1 to 9, characterized in that, Satisfying: 600mm ≤ Dmm ≤ 1800mm; and / or, 25mm≤Bmm≤300mm.

32. The battery pack according to any one of claims 1 to 9, characterized in that, The first heat exchange tube (211) and the second heat exchange tube (212) are made of aluminum alloy, which includes at least Al, Cu and Mn, wherein the mass percentage of Al is greater than or equal to 95wt%, and the sum of the mass percentages of Cu and Mn is 1wt%~1.7wt%.

33. The battery pack according to any one of claims 1 to 9, characterized in that, The first heat exchange tube (211) and the second heat exchange tube (212) are made of stainless steel, and the stainless steel material includes Cr, wherein the mass percentage of Cr is 15wt%~23wt%.

34. An electrical appliance, characterized in that, Includes the battery pack as described in any one of claims 1 to 33.

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