Battery pack and electric device

Abstract

This application discloses a battery pack and an electrical device. The battery pack includes a housing, a heat exchange plate, a heat-conducting component, and a battery assembly. The housing includes a base plate and a frame. The battery assembly includes a battery column composed of at least two individual cells, with each individual cell connected to the base plate. Each individual cell includes a casing, a cover plate, and a cell. The casing and cover plate are welded to form a first welding line, and the cell includes an electrode. A first side of the casing is connected to the heat exchange plate via the heat-conducting component. The distance between the heat exchange plate and the first welding line is d mm along a second direction. The distance between the heat exchange plate and the first welding line is h mm along a third direction. x = d + h. The distance between the electrode and the first welding line is k mm along a third direction. The overlapping area between the orthographic projection of a single battery column along the second direction and the projection of the heat exchange plate is S1 mm. 2 The total area of ​​a single heat exchange plate facing the first side is S mm. 2 The following conditions must be met: 25≤x*k / (S1 / S)≤500; The battery pack provided in this application helps to improve heat dissipation under high-power fast charging conditions, thereby improving charging efficiency and safety.

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 increasing demand for fast charging, battery temperatures rise rapidly during high-power charging and discharging, easily leading to safety risks such as thermal runaway and reducing charging and discharging efficiency. Existing battery thermal management systems typically use bottom-mounted heat exchange plates for heat dissipation, but due to the limited contact area between the heat exchange plate and the battery and an unreasonable heat conduction path, heat exchange efficiency is low, making it impossible to effectively control battery temperature in a timely manner. This causes the battery to heat up too quickly during fast charging, not only prolonging charging time but also increasing safety hazards. Summary of the Invention

[0003] With the aim of at least solving one of the technical problems existing in the prior art, this application aims to provide a battery pack and an electrical device having the battery pack, wherein the battery pack helps to improve heat dissipation under high-power fast charging conditions, and improves charging efficiency and safety.

[0004] To solve the above-mentioned technical problems, this application provides the following technical solution: a battery pack, including a housing, a heat exchange plate, a heat-conducting component, and a battery pack; the housing includes a bottom plate and a frame connected to each other, the bottom plate and the frame enclosing an accommodating space, the thickness direction of the bottom plate being a third direction; a heat exchange channel is provided inside for passing a heat exchange medium, the heat exchange plate is disposed in the accommodating space, the heat exchange plate is connected to the bottom plate and / or the frame, the length direction of the heat exchange plate is a first direction; the battery pack is disposed on the upper part of the bottom plate, the battery pack includes a battery column composed of at least two individual cells arranged along the first direction, the individual cells being connected to the bottom plate; the individual cell includes a casing, a cover plate, and a cell, the casing including At least one opening is provided, and a cover plate is welded to the opening to form a first weld line. The housing and the cover plate form a receiving cavity, and the battery cell is disposed within the receiving cavity. The battery cell includes an electrode. A first side of the housing is perpendicular to the bottom plate and connected to the heat exchange plate via the heat-conducting component. The first direction, the third direction, and the second direction are mutually perpendicular. Along the second direction, the distance between the heat exchange plate and the first weld line is d mm. Along the third direction, the distance between the heat exchange plate and the first weld line is h mm. x = d + h. Along the third direction, the distance between the electrode and the first weld line is k mm. The area overlapping the orthographic projection of a single battery array along the second direction with the projection of the heat exchange plate is S1 mm. 2 The area of ​​a single heat exchange plate facing the first side is S mm. 2 It satisfies: 25≤x*k / (S1 / S)≤500.

[0005] Compared with the prior art, the battery pack of this application has the following advantages: (1) The battery pack provided by this application extends the heat exchange plate along the first direction and connects it with the first side of the single battery through a heat-conducting component, so that the heat exchange plate can exchange heat with the side of the single battery, which increases the heat exchange contact area between the battery and the heat exchange plate, helps to improve the heat dissipation capacity of the battery under high-power fast charging conditions, suppresses the battery temperature rise, and improves charging efficiency and safety.

[0006] (2) The battery pack provided in this application, by limiting 25≤x*k / (S1 / S)≤500, ensures that the heat exchange plate is close enough to the main body of the individual cells to maintain efficient heat conduction, avoiding the large amplitude caused by the heat exchange plate being set vertically to the bottom plate, which would affect the overall structural strength of the battery. In particular, it avoids the mechanical and sealing weakness of the end of the heat exchange plate being close to the welding line, which could lead to the safety risk of the welding line between the shell and the cover plate cracking. When the battery pack is subjected to vibration, impact or thermal cycling, it can reduce the local extrusion or shear stress of the heat exchange plate on the welding line area, preventing welding line cracking, sealing failure and other faults caused by the relative displacement between the heat exchange plate and the individual cells, thereby improving the structural durability and long-term safety of the battery. Attached Figure Description

[0007] Figure 1 This is a schematic diagram of the structure of a battery pack according to an embodiment of this application;

[0008] Figure 2 This is a cross-sectional view of a battery pack according to an embodiment of this application;

[0009] Figure 3 yes Figure 2 Enlarged view of point A;

[0010] Figure 4 This is a schematic diagram showing the dimensional relationship between the heat exchange plate, the electrode, and the first bonding wire in an embodiment of this application;

[0011] Figure 5 This is a schematic diagram of the structure of a single battery row and heat exchange plate according to an embodiment of this application;

[0012] Figure 6 This is a schematic diagram of the orthographic projection of a single battery array and heat exchange plate in a second direction, according to a specific embodiment of this application.

[0013] Figure 7 This is a schematic diagram of the orthographic projection of a single battery array and heat exchange plate in a second direction, according to two specific embodiments of this application.

[0014] Figure 8 This is a schematic diagram of the heat exchange plate according to an embodiment of this application;

[0015] Figure 9This is a cross-sectional view of the heat exchange plate according to an embodiment of this application;

[0016] Figure 10 This is a schematic diagram showing the relationship between the heat exchange plate and the electrode in an embodiment of this application;

[0017] Figure 11 This is a schematic diagram showing the relationship between the first weld line and the first weld surface in an embodiment of this application;

[0018] Figure 12 This is a partial cross-sectional view of the battery pack according to an embodiment of this application;

[0019] Figure 13 This is a second cross-sectional view of a battery pack according to an embodiment of this application;

[0020] Figure 14 yes Figure 13 Enlarged diagram of point B.

[0021] In the diagram, 1 is the box body; 11 is the base plate; 12 is the frame; and 110 is the accommodating space.

[0022] 2. Battery pack; 20. Battery column; 21. Individual cell; 211. Casing; 212. Cover plate; 213. Cell; 214. Electrical connector; 215. Terminal post; 2110. Receiving cavity; 2111. First side; 2112. Thickened area; 2113. Non-thickened area; 2114. Second side; 2131. Electrode; 21311. First electrode end;

[0023] 3. Heat exchange plate; 30. First zone; 31. Structural wall; 310. Heat exchange channel; 311. First partition wall;

[0024] 4. Thermally conductive components; 41. Thermally conductive adhesive layer;

[0025] 5. Conductive busbar;

[0026] 100, First weld line; 200, First weld surface;

[0027] X, first direction; Y, second direction; Z, third direction. Detailed Implementation

[0028] The specific embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this application, but are not intended to limit the scope of this application.

[0029] In the description of this application, it should be understood that the term "comprising" as used in this specification means the presence of the stated features, integers, steps, operations, parts, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, parts, components, and / or groups thereof. It should be understood that when we say a part is "connected" to another part, it can be directly connected to the other part, or there may be intermediate parts. The term "and / or" as used herein includes all or any unit and all combinations of one or more associated listed items.

[0030] With the increasing demand for fast charging, battery temperatures rise rapidly during high-power charging and discharging, easily leading to safety risks such as thermal runaway and reducing charging and discharging efficiency. Existing battery thermal management systems typically use bottom-mounted heat exchange plates for heat dissipation, but due to the limited contact area between the heat exchange plate and the battery and an unreasonable heat conduction path, heat exchange efficiency is low, making it impossible to effectively control battery temperature in a timely manner. This causes the battery to heat up too quickly during fast charging, not only prolonging charging time but also increasing safety hazards.

[0031] To address the aforementioned issues, this application proposes placing a heat exchange plate within the battery pack's accommodating space and connecting it to the side surface (first side) of the individual battery cells via a heat-conducting component. This increases the heat exchange contact area and improves heat transfer efficiency. Furthermore, the heat exchange plate extends in a direction perpendicular to the base plate (i.e., a third direction), allowing simultaneous contact with the sides of multiple individual battery cells, increasing the effective heat exchange area, and enabling the arrangement of more heat exchange units within the same space, thus enhancing thermal management capabilities. However, in actual research and testing, it was found that although this structure effectively improves heat exchange performance, under vibration conditions, relative displacement or misalignment may occur between the heat exchange plate and the battery. This causes the heat exchange plate to apply additional mechanical stress to the first weld line area between the battery cell's casing and cover plate, easily leading to weld line cracking and internal battery seal failure, seriously threatening the battery's safety and reliability.

[0032] Firstly, such as Figures 1 to 14 As shown, this application provides a battery pack, including a housing 1, a battery pack 2, a heat exchange plate 3, and a heat-conducting component 4.

[0033] The housing 1 includes a base plate 11 and a frame 12 connected to each other, forming an accommodating space 110. The thickness direction of the base plate 11 is the third direction Z. A heat exchange plate 3 has a heat exchange channel 310 inside for passing a heat exchange medium. The heat exchange plate 3 is disposed in the accommodating space 110 and is connected to the base plate 11 and / or the frame 12. The length direction of the heat exchange plate 3 is the first direction X. A battery pack 2 is disposed on the upper part of the base plate 11. The battery pack 2 includes a battery array consisting of at least two individual cells 21 arranged along the first direction X. A single battery cell 21 is disposed within the accommodating space 110 and connected to the base plate 11. The single battery cell 21 includes a housing 211, a cover plate 212 and a cell 213. The housing 211 includes at least one opening. The cover plate 212 is welded to the opening and forms a first welding line 100. The housing 211 and the cover plate 212 form an accommodating cavity 2110. The cell 213 is disposed within the accommodating cavity 2110 and includes an electrode 2131. The first side 2111 of the housing 211 is perpendicular to the base plate 11 and is connected to the heat exchange plate 3 through a heat-conducting element 4.

[0034] Wherein, the first direction X, the second direction Y, and the third direction Z are all perpendicular to each other; along the second direction Y, the distance between the heat exchange plate 3 and the first bonding line 100 is d mm; along the third direction Z, the distance between the heat exchange plate 3 and the first bonding line 100 is h mm; x = d + h; along the third direction Z, the distance between the electrode 2131 and the first bonding line 100 is k mm; the overlap area between the orthographic projection of a single battery column along the second direction Y and the projection of the heat exchange plate 3 is S1 mm. 2 The total area of ​​a single heat exchange plate 3 facing the first side 2111 is S mm. 2 It satisfies: 25≤x*k / (S1 / S)≤500.

[0035] Based on this technical solution, the battery pack provided by the present invention extends the heat exchange plate 3 along the first direction X and connects it to the first side 2111 of the single cell 21 through the heat-conducting component 4, so that the heat exchange plate 3 can exchange heat with the side of the single cell 21, thereby increasing the heat exchange between the battery and the heat exchange plate. This helps to improve the heat dissipation capacity of the battery under high-power fast charging conditions, suppresses the temperature rise of the battery, and improves charging efficiency and safety.

[0036] By limiting 25 ≤ x*k / (S1 / S) ≤ 500, x*k / (S1 / S) ≤ 500, the heat exchange plate 3 is ensured to be sufficiently close to the main body of the individual battery cell 21 to maintain efficient heat conduction. This avoids the large amplitude caused by the heat exchange plate 3 being vertically positioned to the base plate 11, which could affect the overall structural strength of the battery. In particular, it avoids the mechanical and sealing weakness of the end of the heat exchange plate 3 near the welding line, which could lead to the safety risk of welding line cracking between the casing and the cover plate. When the battery pack undergoes vibration, impact, or thermal cycling, the local compression or shear stress of the heat exchange plate 3 on the welding line area can be reduced, preventing welding line cracking, sealing failure, and other faults caused by the relative displacement between the heat exchange plate 3 and the individual battery cell 21, thereby improving the structural durability and long-term safety of the battery.

[0037] Specifically, x = d + h represents the comprehensive spatial distance between the heat exchange plate 3 and the first bonding line 100, used to characterize the proximity of the heat exchange plate 3 to the area where the first bonding line 100 is located in three-dimensional space; k is the distance from the top of the electrode 2131 of the cell 213 to the first bonding line 100 in the third direction Z, reflecting the relative positional relationship between the main heat-generating area (electrode 2131) inside the single cell 21 and the external sealing boundary (first bonding line 100). S1 / S is the ratio of the effective heat exchange area of ​​the heat exchange plate 3 to the first side surface 2111 of the single cell 21, where S1 is the actual overlapping heat conduction area of ​​the two, and S is the total surface area of ​​the corresponding side of the heat exchange plate 3. The higher the ratio, the higher the utilization rate of the heat exchange interface and the stronger the heat dissipation capacity. When the heat exchange plate 3 is arranged closer to the main heat-generating area of ​​the single cell 21, S1 / S increases, which is beneficial to improve the heat conduction efficiency, shorten the temperature rise time during charging, and improve fast charging performance. However, if the x-value is too small, meaning the heat exchange plate 3 is too close to the first weld line 100 in the horizontal or vertical direction, a small relative displacement or deformation may occur between the heat exchange plate 3 and the battery when the battery pack experiences vibration, impact, or thermal expansion and contraction caused by temperature cycling during vehicle operation. This dynamic displacement will generate repeated compression, shearing, or bending stresses in the local area of ​​the weld line, which can easily lead to weld metal fatigue and microcrack propagation under long-term action, ultimately causing serious failures such as weld line cracking, sealing failure, and electrolyte leakage. Conversely, if the heat exchange plate 3 is moved away from the welding line to avoid the above risks (x is too large), although the structural safety is improved, it will lead to a significant decrease in S1 / S, a decrease in the utilization rate of the heat exchange area, an increase in thermal resistance, and a deterioration in heat dissipation efficiency, which cannot meet the thermal management requirements of high-rate charging and discharging. This application introduces and limits the comprehensive parameter 25≤x*k / (S1 / S)≤500. When x*k / (S1 / S) is too low, it means that under the conditions of limited safety distance (small x) and heat source close to the welding line (small k), it is still necessary to pursue a high heat exchange area ratio (high S1 / S). Although the heat dissipation is good, the structural risk is high. When x*k / (S1 / S) is too high, safety is good but fast charging performance is limited; however, this application limits x*k / (S1 / S) to the range of 25 to 500, ensuring sufficient heat dissipation efficiency while maintaining sufficient mechanical buffer space between the heat exchange plate 3 and the first welding line 100. When the battery pack experiences vibration, impact or thermal cycling, it can reduce the local compression or shear stress of the heat exchange plate 3 on the welding line area, preventing welding line cracking, sealing failure and other faults caused by the relative displacement between the heat exchange plate 3 and the single cell 21, thereby improving the structural durability and long-term safety of the battery.

[0038] It should be noted that a battery pack generally includes: a battery pack composed of multiple battery modules connected in series and / or in parallel, a battery management system (BMS), a thermal management system, an electrical connection system (high-voltage / low-voltage connectors, wiring harnesses, etc.), structural components (casing, brackets, etc.), and protective components, etc. All of the above components are placed inside the casing and sealed with a cover plate to form a complete functional unit that can directly output electrical energy. It is a rechargeable battery and also the power source for new energy vehicles.

[0039] It should be noted that in the battery pack described in this application, the casing is composed of a base plate and a frame connected to each other, forming an enclosure space for accommodating the battery pack and heat exchange plate. In some embodiments, the base plate and the frame can be connected by welding (such as laser welding, friction stir welding, or metal inert gas welding), bolting or rivet fastening, structural adhesive bonding (such as epoxy resin adhesive, polyurethane adhesive, or thermally conductive structural adhesive), snap-fit ​​or plug-in fitting, etc.; multiple methods can also be used in combination, for example, spot welding and structural adhesive can be used in local areas, or bolted connections can be supplemented with sealing strips to balance connection strength, sealing performance and assembly convenience; in other embodiments, the base plate and the frame can also be integrally formed by processes such as die casting, stamping or injection molding, thereby reducing the connection interface, improving overall rigidity and simplifying the assembly process. Regarding material selection, the base plate and frame can be made of the same or different materials, including but not limited to the following types: metal materials such as aluminum alloys (e.g., 6061, 6082, 5052, 7075, etc.), magnesium alloys (e.g., AZ31B, AM60B), stainless steel (e.g., 304, 316L), cold-rolled steel plates (e.g., SPCC, DC01), and copper alloys; composite materials such as carbon fiber reinforced resin matrix composites (CFRP), glass fiber reinforced plastics (GFRP), or metal-composite hybrid structures (e.g., aluminum honeycomb sandwich panels); engineering plastics such as polyamides (PA6, PA66, with glass fiber reinforcement), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), and thermally conductive engineering plastics with added thermally conductive fillers such as boron nitride and alumina. In a preferred embodiment, both the base plate and the frame are made of 6061-T6 aluminum alloy and connected by friction stir welding, achieving both lightweight design and excellent thermal conductivity and structural strength. In another embodiment, the base plate is made of stainless steel to provide high load-bearing capacity, while the frame is made of glass fiber reinforced PA66 engineering plastic and fixed to stainless steel bolts using high-strength structural adhesive. This design is suitable for applications with special requirements for electrical insulation and corrosion resistance. The above connection methods and material combinations can be flexibly configured according to actual product needs, ensuring the safe and reliable operation of the battery pack while also considering thermal management efficiency, manufacturing costs, and assembly processability.

[0040] In the battery pack described in this application, a heat exchange plate is disposed within the housing space of the casing and is used for thermal management of the battery pack through an internally circulating heat exchange medium (such as coolant). The heat exchange plate can be structurally varied. In a preferred embodiment, the heat exchange plate is a plate structure with multiple parallel or serpentine heat exchange channels arranged internally. The channels extend along the length direction of the heat exchange plate (i.e., the first direction) to match the rows of individual battery cells arranged along this direction, thereby achieving uniform heat exchange. In other embodiments, the heat exchange plate can be a microchannel structure, a double-layer brazed structure, a blown plate structure, or a 3D-printed integrated channel structure. The double-layer brazed structure is formed by high-temperature brazing of two grooved metal plates, resulting in good channel sealing and strong pressure resistance. The blown plate structure is made by pre-setting a channel pattern between two aluminum plates, inflating them, and then welding the edges, offering advantages such as high channel complexity and light weight. The microchannel structure is suitable for high heat flux density scenarios, with a channel width typically less than 1 mm, improving heat exchange efficiency. The material of the heat exchange plate needs to consider thermal conductivity, corrosion resistance, formability, and compatibility with the coolant. It can be selected from, but is not limited to, the following materials: aluminum alloys (such as 3003, 1050, 6063, etc., widely used in blown plates and brazed plates), stainless steel (such as 304, 316L, suitable for high-pressure or highly corrosive environments), copper or copper alloys (excellent thermal conductivity but higher cost and density), and composite metal materials with nickel plating or anti-corrosion coating. In a typical embodiment, the heat exchange plate is made of 3003 aluminum alloy and integrally formed using a blown plate process, ensuring good thermal conductivity while also offering advantages in lightweight and low cost. Regarding the inlet and outlet settings, one or both ends of the heat exchange plate are provided with an inlet and an outlet that communicate with the internal heat exchange channels.

[0041] In a single-pass design, the inlet and outlet are located at opposite ends of the heat exchange plate; in a multi-pass or U-shaped flow channel design, they can be located on the same side for convenient centralized piping arrangement. The inlet and outlet are typically standard quick-connect couplings, threaded connections, or welded flange connections, which can be flexibly configured according to the piping layout of the vehicle's cooling system. To reduce flow resistance and improve flow uniformity, some embodiments also include a flow distribution chamber or flow collector inside the heat exchange plate, ensuring even distribution of coolant to each parallel flow channel.

[0042] The heat exchanger plate is connected to the external cooling system via water pipes. These pipes can be rubber hoses, nylon hoses, PA12 engineering plastic hoses, or composite hoses with braided layers. One end is sealed to the inlet and outlet of the heat exchanger plate via clamps, quick-connect fittings, or threaded fittings. The other end connects to a manifold (also called a collector plate or manifold) outside the battery pack. The manifold is typically made of engineering plastics (such as PPS) or metal (such as aluminum alloy) and has independent inlet and outlet chambers, which are connected in parallel to the inlet and outlet of multiple heat exchanger plates to achieve unified supply and recovery of coolant. The connection between the manifold and the heat exchanger plate can be achieved through an integrated quick-connect structure for rapid assembly, or a sealed flow channel system can be formed at the module level through welding or bonding. In some embodiments, the manifold and heat exchanger plate are integrated as a single unit, further simplifying the fluid loop and reducing the risk of leakage.

[0043] A thermally conductive component is disposed between the first side of the battery cell casing and the heat exchange plate to fill the microscopic gap between them, reduce contact thermal resistance, and improve the efficiency of heat conduction from the battery to the heat exchange plate. Structurally, the thermally conductive component can be a continuous or discontinuous layered structure. In a typical embodiment, the thermally conductive component is a thermally conductive adhesive layer covering the entire contact area between the first side and the heat exchange plate, with a uniform and controllable thickness, capable of fully wetting the interface and adapting to manufacturing tolerances. In other embodiments, the thermally conductive component can be a thermally conductive pad (such as a pre-formed silicone pad, a phase change material pad), thermally conductive foam, thermally conductive gel, thermally conductive grease, or composed of multiple discretely arranged thermally conductive pillars / blocks. Among these, thermally conductive pads are easy to pre-assemble and automate, suitable for mass production; thermally conductive gels or thermally conductive greases have excellent interface filling capabilities, suitable for scenarios with high surface roughness or large assembly gaps; phase change thermally conductive materials can soften and flow at operating temperatures, further reducing thermal resistance.

[0044] In terms of material selection, thermally conductive components can be made of materials including but not limited to silicone-based materials, non-silicon materials, inorganic thermally conductive materials, and metal-based thermal interface materials. Silicone-based materials can be addition-cure silicone rubber (containing thermally conductive fillers such as alumina, boron nitride, and graphene), which has good flexibility, high and low temperature resistance, and electrical insulation. Non-silicon materials can be polyurethane (PU), acrylate, or epoxy resin-based thermally conductive adhesives, which are suitable for applications sensitive to silicon migration (such as near optical or high-voltage devices). Inorganic thermally conductive materials can be thermally conductive mica sheets or ceramic matrix composites, which have high insulation and dimensional stability. Metal-based thermal interface materials can be indium foil, tin-silver alloy foil, etc., which have extremely high thermal conductivity.

[0045] It should be noted that a single battery cell can store chemical energy and can controllably convert chemical energy into electrical energy. In recyclable batteries, a single battery cell can be recharged after discharge to reactivate the active materials and continue to be used. A single battery cell includes a casing and a battery cell housed within the casing.

[0046] It should be noted that the casing is used to encapsulate components such as the battery cell and electrolyte. The casing can come in various shapes and sizes, such as cuboids or hexagonal prisms, and its shape is determined based on the specific shape and size of the battery cell. The casing generally includes a body with an opening at at least one end and a receiving cavity. The opening can be closed with a cover plate to seal and isolate the internal environment of the battery cell from the external environment. The casing material includes, but is not limited to, copper, iron, aluminum, stainless steel, and aluminum alloys.

[0047] It should be noted that a cover plate is a component that closes onto the opening of a housing to isolate the internal space of the housing from the external environment. The shape of the cover plate can be adapted to the shape of the housing to achieve isolation. The materials of the cover plate include, but are not limited to, copper, iron, aluminum, stainless steel, and aluminum alloy.

[0048] It should be noted that a battery cell consists of the cell body and the tabs. The tabs, serving as the current output terminals of the cell, are composed of a positive tab and a negative tab, which are connected to external circuits (such as busbars or battery management systems) to conduct charging and discharging current. The battery cell is the component in the battery where electrochemical reactions occur; it is the smallest unit in the battery capable of carrying out electrochemical reactions such as charging and discharging.

[0049] It should be noted that the battery cell body is constructed from a positive electrode, a negative electrode, and a separator disposed between the positive and negative electrodes through a winding or stacking process, and then encapsulated in a housing. The battery cell body / cell typically includes a separator and two electrodes of opposite polarity, namely the positive and negative electrodes. The battery cell operates by the movement of metal ions between the positive and negative electrodes. The cycling process of the battery cell body is the process of metal ions moving from the positive electrode to the negative electrode, and then from the negative electrode to the positive electrode. The separator of the battery cell is usually a porous insulating material, whose main function is to isolate the positive and negative electrodes while allowing lithium ions to pass through.

[0050] It should be noted that the term "electrode" in this application refers only to the active material coating areas of the positive and negative electrodes within the battery cell body, excluding the tabs. The electrode is the main electrochemical reaction area inside the battery cell and also the primary source of heat generation; while the tab, as a current collector structure, focuses on current collection and transmission. The electrode includes a current collector and an active material layer, with the active material layer coated on the surface of the current collector. If the electrode is a positive electrode, the current collector can be made of aluminum, and the active material layer can be made of lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. If the electrode is a negative electrode, the current collector can be made of copper, and the active material layer can be made of carbon or silicon, etc.

[0051] More preferably, 50≤x*k / (S1 / S)≤400.

[0052] Preferably, 0.3mm≤dmm≤2.6mm, 5mm≤hmm≤25mm, and / or 3.5mm≤kmm≤15mm.

[0053] If d is too small, the heat exchange plate 3 will be too close to the welding line, which will easily generate lateral compressive stress under vibration or assembly deviation, causing the welding line area to crack under shear force. If d is too large, the heat exchange plate 3 will be far away from the main heat-generating area of ​​the single cell 21, the heat conduction path will be extended, and the heat dissipation efficiency will decrease. By limiting the reasonable range of d, an efficient lateral heat conduction path can be maintained between the heat exchange plate 3 and the battery while avoiding mechanical interference.

[0054] h directly affects whether the heat exchange plate 3 is at the same height as the welding line. If h is too small, it indicates that the heat exchange plate 3 overlaps or is close to the welding line in the vertical direction. Even if the horizontal distance is sufficient, it may still cause vertical contact or stress concentration due to local thermal expansion and contraction or structural deformation. If h is too large, the heat exchange plate 3 is located in the non-heat-generating core area of ​​the battery and cannot effectively dissipate the heat generated by the electrode 2131. Limiting the value range of h helps to arrange the heat exchange plate 3 in the heat source concentration area of ​​the single cell 21 (such as the upper part of the electrode 2131) while avoiding the sealing sensitive area where the welding line is located.

[0055] k reflects the relative position between the high heat density area inside the single cell 21 and the weak area of ​​the external structure. If k is too small, it means that the heat-generating area of ​​the electrode 2131 is close to the first welding line 100, and the heat is easy to diffuse to the weld area, resulting in increased local temperature rise and high risk of thermal stress concentration; if k is too large, the heat source is far away from the welding line, which is not conducive to the heat exchange plate 3 completely covering the main heat-generating area of ​​the single cell 21.

[0056] dmm can be any value that satisfies 0.3mm≤dmm≤2.6mm, such as 0.3mm, 0.5mm, 1.0mm, 1.2mm, 1.5mm, 2.0mm, 2.1mm, 2.2mm, 2.4mm, 2.5mm, 2.6mm.

[0057] hmm can be any value that satisfies 5mm≤hmm≤25mm, such as 5mm, 8mm, 10mm, 12mm, 15mm, 20mm, 21mm, 22mm, 24mm, 25mm, etc.

[0058] kmm can be any value that satisfies 3.5mm ≤ kmm ≤ 15mm, such as 3.5mm, 4mm, 5mm, 10mm, 15mm, etc.

[0059] In some embodiments, the penetration direction of the first weld line 100 is perpendicular to the top surface of the cover plate 212, and the penetration dimension of the first weld line 100 is G1, preferably 1mm≤G1mm≤4.5mm.

[0060] By limiting the penetration depth of the first weld line 100 to 1mm≤G1≤4.5mm, the mechanical strength and thermal interface quality of the weld between the housing 211 and the cover plate 212 are optimized, thereby improving the electrical connection reliability, thermal conductivity and long-term safety of the battery pack.

[0061] Specifically, if G1 is too small (<1mm), the penetration depth is insufficient, resulting in insufficient welding strength. Under vibration or thermal cycling conditions, the weld joint is prone to loosening and the contact resistance increases. If G1 is too large (>4.5mm), the penetration depth is too deep, which damages the structural integrity of the shell 211 and causes stress concentration points (such as local deformation or microcracks in the shell 211). Under vibration, the weld is prone to cracking, affecting the sealing performance.

[0062] It should be noted that in the battery pack structure, the housing 211 and the cover plate 212 are welded to form a first weld line 100 (i.e., the welding area between the housing 211 and the cover plate 212). The penetration direction of the first weld line 100 is perpendicular to the top surface of the cover plate 212, meaning that the extension direction of the weld penetration is perpendicular to the plane where the top surface of the cover plate 212 (i.e., the upper surface of the cover plate 212) contacts and welds with the housing 211. Specifically, the top surface of the cover plate 212 refers to the upper surface of the cover plate 212 (the contact surface with the housing 211), which is usually a horizontal plane (parallel to the bottom surface of the housing 211). The penetration direction of the first weld line 100 refers to the direction in which the molten metal extends into the housing 211 during the welding process. When the penetration direction is perpendicular to the top surface of the cover plate 212, the penetration path is along the thickness direction of the cover plate 212 (i.e., perpendicular to the top surface of the cover plate 212, pointing into the housing 211), rather than parallel to the top surface of the cover plate 212.

[0063] G1mm can be any value such as 1mm, 2mm, 3mm, 4mm, 4.5mm, etc., satisfying 1mm≤G1mm≤4.5mm.

[0064] In some embodiments, the penetration direction of the first weld line 100 is parallel to the top surface of the cover plate 212, and the penetration dimension of the first weld line 100 is G2, preferably 1mm≤G2mm≤2.5mm.

[0065] By limiting the penetration direction of the first weld line 100 to be parallel to the top surface of the cover plate 212 and controlling the penetration dimension G2 within the range of 1mm to 2.5mm, the feasibility of the welding process and the quality of the thermal interface are optimized, significantly improving the thermal conductivity and mechanical reliability of the battery pack. Specifically, if G2 is too small (<1mm): insufficient penetration dimension leads to poor weld continuity, forming a tiny gap (extremely high thermal resistance) between the cover plate 212 and the shell 211, interrupting the heat conduction path; if G2 is too large (>2.5mm): excessive penetration depth damages the structural integrity of the cover plate 212, causing local deformation or stress concentration points in the cover plate 212, making the weld joints prone to loosening under vibration conditions, and potentially causing the cell 213 to fail to seal.

[0066] It should be noted that in the battery pack structure, the housing 211 and the cover plate 212 are welded to form a first weld line 100 (i.e., the welding area between the housing 211 and the cover plate 212). The penetration direction of the first weld line 100 is parallel to the top surface of the cover plate 212, which means that the extension direction of the weld penetration is parallel to the top surface of the cover plate 212 (i.e., the upper surface of the cover plate 212, the plane that contacts and welds with the housing 211). Specifically, the top surface of the cover plate 212 refers to the upper surface of the cover plate 212 (the contact surface with the housing 211), which is usually a horizontal plane (parallel to the bottom surface of the housing 211). The penetration direction of the first weld line 100 refers to the direction in which the molten metal extends into the housing 211 during the welding process. When the penetration direction is parallel to the top surface of the cover plate 212, the penetration path is along the plane direction of the top surface of the cover plate 212 (i.e., parallel to the top surface of the cover plate 212, extending horizontally along the upper surface of the cover plate 212), rather than perpendicular to the top surface of the cover plate 212.

[0067] G2mm can be any value that satisfies 1mm≤G2mm≤2.5mm, such as 1mm, 1.5mm, 1.8mm, 2mm, 2.5mm, etc.

[0068] Preferably, 28800mm 2 ≤S1mm 2 ≤274560mm 2 If S1 is too small, the insufficient overlapping area leads to uneven thermal interface contact and increased thermal resistance; if S1 is too large, although the heat exchange potential is high, the increase in the number of individual cells leads to structural redundancy and increased cost.

[0069] Preferably, 40000mm 2 ≤Smm 2 ≤286000mm 2 If S is too small, the heat exchange plate 3 will be insufficient in size, limiting its heat dissipation capacity and failing to meet the thermal management requirements under high-power conditions; if S is too large, structural redundancy will lead to material waste, increase the overall size of the battery pack, and affect the compactness of the space layout.

[0070] Preferably, 0.72≤S1 / S≤0.96. If S1 / S is too small, the overlap ratio is low, the effective heat exchange area is insufficient, the thermal resistance increases, and the heat conduction efficiency decreases; if S1 / S is too large, although the contact area is large, S may be too large, causing mechanical interference or thermal interface stress concentration, which will increase the thermal resistance.

[0071] Preferably, 3.5mm ≤ kmm ≤ 15mm. By limiting the length of the heat conduction path inside the battery to 3.5mm ≤ kmm ≤ 15mm, the length can be optimized, ensuring that heat is efficiently and evenly transferred from the electrode 2131 of the cell 213 to the first bonding line 100, thereby improving the thermal management efficiency and electrochemical stability of the battery pack. Specifically, if k is too small, the distance between the electrode 2131 and the first bonding line 100 will be too close, which can easily lead to a sharp increase in heat flux density and cause local overheating in the electrode 2131 area; if k is too large, the heat conduction path will be lengthened, and the thermal resistance will increase.

[0072] In some embodiments, the cover plate 212 is disposed on the end face of the single cell 21 away from the bottom plate 11, and the first welding line 100 welds the cover plate 212 and the housing 211 together, satisfying: 5mm≤hmm≤20mm.

[0073] By limiting the range h to 5mm≤hmm≤20mm, the geometry of the heat conduction path and the safety of the welding process can be optimized, thereby improving the thermal management efficiency of the battery pack, the protection capability of cell 213, and the structural reliability.

[0074] Specifically, if h is too small, the distance between the heat exchange plate 3 and the first welding line 100 will be too close, which may easily cause mechanical interference under assembly or vibration conditions (such as the heat exchange plate 3 contacting the outside of the cover plate 212); if h is too large, the heat conduction path "cell 213 - shell 211 - first welding line 100 - heat exchange plate 3" will be extended, the thermal resistance will increase, and the heat dissipation efficiency will decrease.

[0075] In some embodiments, the single cell 21 further includes a terminal post 215, which is disposed on the side of the housing 211 away from the cover plate 212 and connected to the cell 213; preferably, 4.5mm≤kmm≤15mm.

[0076] By positioning the electrode post 215 on the side of the housing 211 away from the cover plate 212 (i.e., the bottom of the housing 211), the heat generated by the current flowing through the electrode post 215 (such as the Joule heat from the current passing through the electrode post 215) diffuses within the bottom plane of the housing 211, rather than concentrating on the top of the cover plate 212 (the area near the first bonding line 100). By limiting the length to 4.5mm ≤ kmm ≤ 15mm, the geometric length of the heat conduction path can be optimized, achieving a balance between minimizing thermal resistance and ensuring uniform heat distribution.

[0077] Specifically, if k is too small, the heat conduction path is too short, resulting in an increase in heat flux density in the 2131 region of the electrode, and heat cannot be effectively dissipated, increasing the rate of temperature rise of the battery by more than 25%; if k is too large, the heat conduction path is extended, the thermal resistance increases, and the heat retention in the 2131 region of the electrode is aggravated.

[0078] It should be noted that the terminals are conductive components that connect the internal electrodes of the battery to the external circuitry. Terminal materials typically possess high conductivity, corrosion resistance, and mechanical strength, such as aluminum (Al) or aluminum alloys, copper (Cu) or nickel-plated copper. In some high-voltage applications, copper-aluminum composite structures can also be used for the terminals. Furthermore, the surface of the terminals may be coated with a layer of plating, such as nickel or silver, to enhance corrosion resistance and weldability, ensuring long-term stable battery operation.

[0079] In some implementations, see Figure 3 and Figure 4 The heat exchange plate 3 and the battery array 20 form a first region 30 opposite each other. In the first region 30, along the third direction Z, the top surface of the heat exchange plate 3 is lower than the top surface of the cover plate 212.

[0080] By setting the top surface of the heat exchange plate 3 along the third direction Z (the height direction of the single cell 21) to be lower than the top surface of the cover plate 212, it is ensured that the heat exchange plate 3 will not protrude above the cover plate 212 in the internal structure of the battery pack, thereby avoiding the risk of deformation, damage or positional displacement of the heat exchange plate 3 due to external impact, vibration or installation interference during battery pack assembly, transportation or use.

[0081] It should be noted that the first region 30 refers to the region corresponding to the battery array 20 along the length direction (i.e., the first direction X) of the heat exchange plate 3, specifically the projected range defined by the two ends of the battery array 20 in the first direction X. In other words, the first region 30 is the section of the heat exchange plate 3 directly opposite the main body of the battery array 20 (excluding the extension structures other than the ends of the battery array), and its boundary is defined by the position of the end faces of the two outermost individual cells 21 of the battery array 20 in the first direction X.

[0082] It should be noted that in practical applications, heat exchange plates are usually connected to a manifold (also called a collector plate or manifold) at their ends to collect the cooling medium channels of multiple heat exchange plates. Since the manifold needs to accommodate the channel chambers and interface structures, its overall height (along the third direction Z) is often greater than the heat exchange plate 3 body, and may even be higher than the top surface of the cover plate 212 of the single cell 21. The statement in this application that "the top surface of the heat exchange plate 3 is lower than the top surface of the cover plate 212" only applies to the aforementioned first region 30 and does not cover the non-heat exchange area at the end where the heat exchange plate connects to the manifold.

[0083] See Figure 3 and Figure 4Along the third direction Z, the end of electrode 2131 closest to cover plate 212 is the first electrode end 21311, located between the top surface of cover plate 212 and the top surface of heat exchange plate 3. By limiting the first electrode end 21311 to be located between the top surface of cover plate 212 and the top surface of heat exchange plate 3 in the third direction Z, the main heat source inside the single cell 21 (the end of electrode 2131) is placed within the effective heat conduction range between the heat exchange plate and cover plate, thereby shortening the path of heat transfer from the cell to the heat exchange plate and improving thermal management efficiency. At the same time, in coordination with the setting where the top surface of the heat exchange plate is lower than the top surface of the cover plate, it ensures that the heat source area is both far away from the welding line to avoid local overheating and damage to the sealing structure, and close to the heat exchange plate to achieve rapid heat dissipation, which helps to quickly reduce the battery temperature rise rate and hot spot temperature difference, balancing heat dissipation performance and structural safety.

[0084] When the first electrode end 21311 is located between the top surface of the cover plate 212 and the top surface of the heat exchange plate 3, the distance between the first electrode end 21311 and the top surface of the heat exchange plate 3 along the third direction Z is D1mm, preferably 0mm≤D1mm≤15mm.

[0085] Limiting D1 to 15mm can prevent the height gap between the first electrode end 21311 and the top surface of the heat exchange plate 3 from being too large, which would weaken the effective contact area between the heat exchange plate 3 and the first side 2111 of the housing 211 (too much misalignment in the height direction). This ensures that the heat exchange plate 3 can still stably adhere to the housing 211 through the heat-conducting component 4 during vibration, without affecting the basic heat dissipation function.

[0086] D1mm can be any value such as 1mm, 2mm, 5mm, 10mm, 15mm, etc., satisfying 0mm≤D1mm≤15mm.

[0087] See Figure 3 and Figure 4 The single cell 21 also includes an electrical connector 214, which is connected to the cell 213; along the third direction Z, at least a portion of the electrical connector 214 is located between the top surface of the heat exchange plate 3 and the first welding line 100.

[0088] By positioning at least a portion of the electrical connector 214 between the top surface of the heat exchange plate 3 and the first welding line 100, the electrical connector 214 can conduct heat quickly through the side wall of the housing 211 to the heat exchange plate 3, thereby improving the heat exchange efficiency.

[0089] In the field of battery pack technology, electrical connector 214 refers to a conductive component used to realize the electrical connection between battery cell 213 and external circuit.

[0090] Optionally, the electrical connector 214 may be an adapter plate and / or a tab.

[0091] It should be noted that the adapter plate, as a conductive component of the battery, is mainly used to achieve reliable connection and current transmission between the cells 213 and between the cells 213 and the terminals 215. Furthermore, it can maintain the relative position of the cells 213 and terminals 215 when the battery experiences vibration or temperature changes, preventing the connection points from loosening. Therefore, the material of the adapter plate usually balances conductivity and lightweight. For example, the adapter plate connecting the positive terminal is usually made of aluminum or aluminum alloy (such as 1060 aluminum); the adapter plate connecting the negative terminal is usually made of copper or nickel-plated copper. For some high-power applications, some batteries may also use copper-aluminum composite materials to make the adapter plate.

[0092] The tabs are components of a single battery cell 213. The tabs electrically connected to the electrode plate 2131 typically include a positive tab and a negative tab. The positive tab is electrically connected to the positive electrode plate 2131, and the negative tab is electrically connected to the negative electrode plate 2131. The battery cell 213 is charged and discharged through the positive and negative tabs. Of course, both the positive and negative tabs usually consist of multiple tab layers.

[0093] Tabs are typically current collector structures or composite current collector structures. Tabs with current collector structures usually include a metal layer; that is, in this type of tab, the tab layer is a metal layer. Tabs with composite current collector structures include both metal and non-metal layers; that is, in this type of tab, the tab layers are both metal and non-metal layers. The metal layer can be made of aluminum or copper, and the non-metal layer can be a polymer layer, such as polypropylene (PP), polyimide (PI), or polyethylene terephthalate (PET).

[0094] Along the length of the cover plate 212, the length dimension of the cover plate 212 is L1mm, and the dimension of the electrical connector 214 is L2mm.

[0095] Preferably, 0.15 ≤ L2 / L1 ≤ 0.5. The electrical connector 214 needs to transmit fast-charging current, and the L2 / L1 ratio directly affects its performance: a ratio that is too low (L2 too small) will result in insufficient conductive cross-sectional area, increased current density, and a tendency for localized overheating; a ratio that is too high (L2 too large) will cause part of the electrical connector 214 to extend beyond the heat exchange plate 3's heat dissipation range, creating a heat dissipation blind zone. Therefore, this application limits L2 / L1 to the range of 0.15 ≤ L2 / L1 ≤ 0.5, ensuring that L2 is large enough to reduce current density and resistive heating, while also limiting L2 to a reasonable proportion of the cover plate 212's length. This ensures that the electrical connector 214 is entirely within the heat exchange plate 3's coverage area, achieving a balance between conductivity efficiency and heat dissipation uniformity, and avoiding electrical performance degradation or sealing risks caused by overheating.

[0096] In some embodiments, the length direction of the cover plate 212 is the second direction Y, and the dimension of the cover plate 212 in the second direction Y is its length dimension L1. Similarly, the dimension of the electrical connector 214 in the second direction Y is its length dimension L2. In other embodiments, the length direction of the cover plate 212 is the first direction X, and the dimension of the cover plate 212 in the first direction X is its length dimension L1. Similarly, the dimension of the electrical connector 214 in the first direction X is its length dimension L2.

[0097] It should be noted that the bottom surface of the cover plate 212 refers to the surface of the cover plate 212 facing the battery cell 213, and the top surface of the cover plate 212 refers to the surface of the cover plate 212 away from the battery cell 213. That is, the top surface and the bottom surface of the cover plate 212 are set opposite to each other.

[0098] See Figure 3 , Figure 4 , Figure 8 and Figure 9 The heat exchange plate 3 has a heat exchange channel 310, which extends along the first direction X; along the third direction Z, the distance between the heat exchange channel 310 closest to the first welding line 100 and the first welding line 100 in the heat exchange plate 3 is D4mm, which satisfies: 5.3mm≤D4mm≤28mm.

[0099] The heat exchange channel 310 extends along the first direction X to match the heat dissipation requirements of the battery pack 2 (multiple individual cells 21 arranged along the first direction X). The first bonding line 100 is the sealing core between the housing 211 and the cover plate 212, and the heat exchange channel 310 is a key component for heat dissipation. By limiting D4 to the range of 5.3mm≤D4mm≤28mm, the influence of channel temperature and bonding line protection can be balanced. This avoids D4 being too small (<5.3mm), where temperature fluctuations in the heat exchange channel 310 are directly conducted to the first bonding line 100, affecting the solder strength. It also prevents D4 from being too large (>28mm), where the heat exchange channel 310 is too far from the first bonding line 100, causing heat to accumulate around the first bonding line 100 and soften the solder. This ensures stable temperature in the welding area between the cover plate 212 and the housing 211, preventing cracking and ensuring the sealing performance of the individual cells 21.

[0100] D4mm can be any value that satisfies 5.3mm ≤ D4mm ≤ 28mm, such as 5.3mm, 6mm, 7mm, 8mm, 10mm, 15mm, 20mm, 25mm, 28mm, etc.

[0101] Along the third direction Z, within the heat exchange plate 3, there is a first partition wall 311 between two adjacent heat exchange channels 310. The distance between the first partition wall 311 closest to the first weld line 100 and the first weld line 100 within the heat exchange plate 3 is D5mm; preferably, 8mm≤D5mm≤30mm.

[0102] If D5 is too small (<8mm), the first partition wall 311 is easily affected by the temperature fluctuation of the flow medium, and the temperature difference is transmitted to the first bonding wire 100 through the shell 211, weakening the solder strength. If D5 is too large (>30mm), the heat exchange effect of the heat exchange flow closest to the first bonding wire 100 on the area of ​​the first bonding wire 100 is reduced, resulting in heat accumulation near the first bonding wire 100. By limiting 8mm≤D5mm≤30mm, both temperature difference damage to the bonding wire is avoided, heat dissipation in the bonding wire area is ensured, and sealing reliability is maintained.

[0103] D5mm can be any value of 8mm ≤ D5mm ≤ 30mm, such as 8mm, 10mm, 15mm, 20mm, 25mm, 30mm, etc.

[0104] The heat exchange channel 310 of the heat exchange plate 3 is formed by multiple structural walls 31, and the wall thickness of the structural wall 31 is E1mm.

[0105] Preferably, 0.3mm≤E1mm≤3mm.

[0106] By limiting the wall thickness E1 of the structural wall 31 of the heat exchange plate 3 (which includes the side wall, top wall, bottom wall, and first partition wall 311 of the heat exchange plate 3) to within the range of 0.3 mm to 3 mm, the heat transfer efficiency and structural strength of the heat exchange plate 3 can be balanced, thereby improving the thermal management performance and reliability of the battery pack. Specifically, if E1 is too small (<0.3 mm), the structural wall 31 is too thin, resulting in insufficient mechanical strength of the heat exchange plate 3. During vibration, assembly pressure, or thermal cycling, local deformation or micro-cracks may easily occur, disrupting the uniformity of the thermal interface, increasing thermal resistance, and causing local hot spots. If E1 is too large (>3 mm), the wall thickness is too thick, which prolongs the path of heat transfer from the heat exchange channel 310 to the outside, increases thermal resistance, reduces heat exchange efficiency, and causes uneven temperature distribution of the heat exchange plate 3, affecting the overall thermal management effect of the battery pack.

[0107] E1mm can be any value that satisfies 0.3mm≤E1mm≤3mm, such as 0.3mm, 0.5mm, 1.0mm, 1.2mm, 1.5mm, 2.0mm, 2.1mm, 2.2mm, 2.4mm, 2.5mm, 3mm, etc.

[0108] It should be noted that the side wall of the heat exchange plate 3 is a structural wall 31, and the wall thickness of the side wall of the heat exchange plate 3 is E1mm; the top wall of the heat exchange plate 3 is a structural wall 31, and the wall thickness of the top wall of the heat exchange plate 3 is E1mm; the bottom wall of the heat exchange plate 3 is a structural wall 31, and the wall thickness of the bottom wall of the heat exchange plate 3 is E1mm; the first partition wall 311 of the heat exchange plate 3 is a structural wall 31, and the wall thickness of the first partition wall 311 of the heat exchange plate 3 is E1mm.

[0109] When the thickness direction of structural wall 31 is the second direction Y, the dimension of structural wall 31 in the second direction Y is its wall thickness E1. When the thickness direction of structural wall 31 is the third direction Z, the dimension of structural wall 31 in the third direction Z is its wall thickness E1.

[0110] In some implementations, see Figure 8 and Figure 9 The heat exchange plate 3 has multiple heat exchange channels 310 spaced apart along the third direction Z; along the third direction Z, the distance between two adjacent heat exchange channels 310 is D7mm.

[0111] Preferably, 0.3mm≤D7mm≤3mm.

[0112] By limiting the spacing D7 of adjacent heat exchange channels 310 along the third direction Z (height direction) within the heat exchange plate 3 to within the range of 0.3mm to 3mm, the synergistic balance between heat exchange efficiency and structural strength can be optimized, thereby improving the heat dissipation performance and long-term reliability of the battery pack. Specifically, if D7 is too small (<0.3mm), the spacing between adjacent heat exchange channels 310 is too close, resulting in a decrease in the local mechanical strength of the heat exchange plate 3. Under vibration or thermal cycling conditions, microcracks, structural deformation, or thermal interference between channels may easily occur, disrupting the uniformity of the thermal interface. If D7 is too large (>3mm), the spacing between adjacent heat exchange channels 310 is too wide, reducing the effective heat exchange area per unit volume and decreasing the heat transfer efficiency.

[0113] D7mm can be any value that satisfies 0.3mm≤D7mm≤3mm, such as 0.3mm, 0.5mm, 1.0mm, 1.2mm, 1.5mm, 2.0mm, 2.1mm, 2.2mm, 2.4mm, 2.5mm, 3mm, etc.

[0114] The thickness of heat exchange plate 3 is E4.

[0115] Preferably, 2.5mm≤E4mm≤25mm.

[0116] By limiting the thickness E4mm of the heat exchange plate 3 to within 2.5mm ≤ E4mm ≤ 25mm, a balance can be struck between heat transfer efficiency and mechanical structural strength, thereby improving the heat dissipation performance, long-term reliability, and manufacturing feasibility of the battery pack. Specifically, if E4 is too small (< 2.5mm), the heat exchange plate 3 becomes too thin, resulting in insufficient mechanical strength and making it prone to local deformation or micro-cracks under vibration, assembly pressure, or thermal cycling conditions; if E4 is too large (> 25mm), the increased thickness of the heat exchange plate 3 lengthens the path of heat conduction from the heat exchange channel 310 to the outside, increasing thermal resistance.

[0117] When the thickness direction of the heat exchange plate 3 is the second direction Y, the dimension of the heat exchange plate 3 in the second direction Y is its wall thickness E4. When the thickness direction of the heat exchange plate 3 is the third direction Z, the dimension of the heat exchange plate 3 in the third direction Z is its wall thickness E4.

[0118] E4mm can be any value that satisfies 2.5mm≤E4mm≤25mm, such as 2.5mm, 3mm, 5mm, 10mm, 12mm, 15mm, 20mm, 25mm, etc.

[0119] See Figure 5 and Figure 6 In one particular embodiment, along the first direction X, one end of the heat exchange plate 3 extends beyond the end of the battery pack 2, and the dimension of the heat exchange plate 3 extending beyond the end of the battery pack 2 is F; in this particular embodiment, a single battery column 20 includes twenty-two individual cells 21.

[0120] See Figure 7 In one particular embodiment, along the first direction X, the two ends of the heat exchange plate 3 extend beyond the ends of the battery pack 2, and the dimension of the heat exchange plate 3 extending beyond the ends of the battery pack 2 is F; in this particular embodiment, a single battery column 20 includes twenty individual battery cells 21.

[0121] It should be noted that, in this application, along the first direction X (i.e., the arrangement direction of the battery array 20), at least one end of the heat exchange plate 3 extends beyond the end of the battery pack, and the dimension of this extended portion is denoted as F. The heat exchange plate referred to here only includes its body and the internal heat exchange channel portion, excluding external fluid distribution structures such as the current collector (or manifold, conduit) connected to the end of the heat exchange plate. In other words, dimension F refers to the distance between the end face of the heat exchange plate 3 itself (including the channel area) and the end face of the outermost single cell 21 of the battery array 20, not measured from the end of the current collector.

[0122] Preferably, 25mm ≤ Fmm ≤ 70mm.

[0123] By limiting the dimension F of the heat exchange plate 3 extending beyond the end of the battery pack 2 along the first direction X to 25mm≤Fmm≤70mm, the heat dissipation efficiency and structural compactness of the heat source at the end of the battery pack can be optimized, improving thermal management performance and overall reliability. Specifically, if F is too small (<25mm), the extension dimension of the heat exchange plate 3 is insufficient, failing to effectively cover the heat source at the end of the battery pack 2, causing heat to remain in the end region of the battery pack 2; if F is too large (>70mm), the extension dimension is too large, increasing the weight of the heat exchange plate 3 and structural redundancy, making it prone to interference with the side wall of the housing 1 during vibration or assembly, disrupting the continuity of the thermal interface, and extending the heat conduction path, thus reducing heat dissipation efficiency; an excessively large extension dimension also increases the manufacturing cost of the battery pack.

[0124] Fmm can be any value that satisfies 25mm≤Fmm≤70mm, such as 25mm, 30mm, 40mm, 50mm, 60mm, 70mm, etc.

[0125] In some embodiments, the heat exchange plate 3 is directly connected to the base plate 11, avoiding gaps between the heat exchange plate 3 and the base plate 11, thereby optimizing the heat transfer efficiency from the bottom heat source of the battery (bottom surface of the single cell 21) to the heat exchange plate 3. Specifically, the direct connection eliminates any gaps in air or insulation material that may exist between the heat exchange plate 3 and the base plate 11, allowing heat to be seamlessly transferred through the path of "bottom surface of single cell 21 — base plate 11 — heat exchange plate 3", thus reducing thermal resistance. The rigid connection between the heat exchange plate 3 and the base plate 11 enhances the overall mechanical strength of the battery pack, reducing the possibility of component displacement or loosening under vibration or impact conditions.

[0126] In some implementations, see Figure 3 and Figure 4 The heat-conducting component 4 is a heat-conducting adhesive layer 41. The heat exchange plate 3 is connected to the first side 2111 of the shell 211 through the heat-conducting adhesive layer 41. The thickness of the heat-conducting adhesive layer 41 is E2, which satisfies: 0.5mm≤E2mm≤2.5mm.

[0127] By limiting the thickness E2 of the thermally conductive adhesive layer 41 to within the range of 0.5mm to 2.5mm, the thermal interface contact quality between the heat exchange plate 3 and the first side surface 2111 of the housing 211 can be optimized, thereby improving heat transfer efficiency and structural reliability. Specifically, if E2 is too small (<0.5mm), the thermally conductive adhesive layer 41 is too thin and cannot fully fill the tiny gap between the first side surface 2111 of the housing 211 and the heat exchange plate 3, resulting in uneven contact surfaces (such as local voids or insufficient pressure), forming high thermal resistance areas, and hindering the efficient transfer of heat from the housing 211 to the heat exchange plate 3; if E2 is too large (>2.5mm), the thermally conductive adhesive layer 41 is too thick, extending the heat transfer path (the thermal conductivity of the thermally conductive adhesive is lower than that of the metal housing 211), increasing thermal resistance, increasing the residence time of heat at the interface, and preventing timely heat dissipation, thus exacerbating the risk of local overheating of the battery.

[0128] E2mm can be any value that satisfies 0.5mm, 1mm, 1.5mm, 2mm, etc., where 0.5mm≤E2mm≤2.5mm.

[0129] In some implementations, E2 = d.

[0130] In some embodiments, the outer surface of the battery cell 213 is wrapped with an insulating film of thickness E3, satisfying the following: 50μm≤E3μm≤110μm. By limiting E3 to 110μm, electrical insulation safety and thermal conductivity are balanced, improving the thermal management performance and reliability of the battery pack. Specifically, if E3 is too small, the insulating film thickness is insufficient, which cannot effectively block the risk of electrical short circuits between the battery cells 213 or between the battery cell 213 and the casing 211, easily leading to partial discharge or thermal runaway; at the same time, if the film layer is too thin, the thickness will be uneven, forming a discontinuous thermal interface and increasing local thermal resistance. If E3 is too large, the thermal resistance of the insulating film will increase, prolonging the path of heat transfer from the battery to the casing 211 and reducing thermal conductivity.

[0131] It should be noted that the insulating film is usually Mylar film, which is wrapped around the outer side of the battery cell 213 to prevent the battery cell 213 from contacting the metal casing and causing a short circuit.

[0132] The side surface of the housing 211 includes a large surface and a small surface. The large surface refers to the side surface with a larger area in the housing 211, and the small surface refers to the side surface with a smaller area in the housing 211.

[0133] In some embodiments, the heat exchange plate 3 is connected to the large surface of the housing 211 via a heat-conducting element 4. That is, the first side surface 2111 is the large surface of the housing 211.

[0134] In some embodiments, the housing 211 includes two opposing first side surfaces 2111 and two opposing second side surfaces 2114, which are disposed perpendicular to the base plate 11. The first side surface 2111 is larger than the second side surface 2114, preferably 10mm ≤ xmm ≤ 27.6mm. When the first side surface of the housing 211 is the side surface with the largest area, the heat exchange plate 3 can obtain a larger heat exchange area, thereby increasing the lower limit of x to 10mm while ensuring heat dissipation performance. This increased safety distance can help avoid interference between the heat exchange plate and the first weld line during vibration or assembly, reduce the risk of weld line cracking and seal failure, and improve manufacturing tolerance and structural reliability.

[0135] In some implementations, see Figures 5 to 7 The first side 2111 is smaller than the second side 2114, preferably 0.72≤S1 / S≤0.96.

[0136] By designating the side surface with the smallest area of ​​the housing 211 as the first side surface 2111, and limiting it to 0.72≤S1 / S≤0.96, structural economy and assembly reliability are optimized while ensuring heat exchange efficiency. Specifically, if S1 / S is too small (e.g., <0.72), the overlap area between the heat exchange plate 3 and the housing 211 is insufficient, resulting in a decrease in heat transfer efficiency between the individual battery 21 and the heat exchange plate 3; if S1 / S is too large (e.g., >0.96), since the first side surface 2111 has the smallest area, an excessively large S1 / S means that the size of the heat exchange plate 3 is relatively too large, which is prone to interference with the housing 211 during assembly or vibration, leading to local stress concentration, thermal interface deformation, which in turn increases thermal resistance and causes mechanical risks.

[0137] In some implementations, see Figure 10 Along the third direction Z, the end of the electrode 2131 closest to the cover plate 212 is the first electrode end 21311. The top surface of the heat exchange plate 3 is located between the first electrode end 21311 and the top surface of the cover plate 212, and the distance between the top surface of the heat exchange plate 3 and the first electrode end 21311 is D2mm, which satisfies: 3.5mm≤D2mm≤15mm.

[0138] During fast charging of the battery, the electrode 2131 of the cell 213 is the core electrochemical reaction area. The heat generated by it is easily conducted upward along the height direction (third direction Z) of the casing 211 to the first electrode end 21311 near the cover plate 212. Since the heat dissipation capacity of the cover plate 212 itself is weak, if the heat in the area of ​​the first electrode end 21311 cannot be dissipated in time, heat will easily accumulate at the top of the battery, which will not only affect the charging and discharging efficiency, but may also cause abnormal electrochemical performance due to excessive local temperature of the electrode 2131. By positioning the top surface of the heat exchange plate 3 between the first electrode end 21311 and the top surface of the cover plate 212 in the third direction Z, the heat exchange plate 3 located outside the housing 211 can directly correspond to the upper region where the first electrode end 21311 is located inside the housing 211. Heat can be quickly transferred from the housing 211 to the heat exchange plate 3 on the outside, forming a short-path heat dissipation channel between the first electrode end 21311, the housing 211, the heat conductor 4 and the heat exchange plate 3, thereby improving the heat dissipation efficiency of the top of the battery.

[0139] By limiting the diameter to 3.5mm≤D2mm≤15mm, on the one hand, it can prevent the temperature fluctuation of the heat exchange plate 3 (such as the low temperature of the heat exchange plate 3 during heat dissipation) caused by an excessively small D2 from being quickly transferred to the first electrode end 21311 through the shell 211; on the other hand, it can prevent the heat from being transferred from the first electrode end 21311 to the heat exchange plate 3 by an excessively large D2, thereby reducing heat conduction loss, further alleviating the problem of heat retention at the top of the battery, and achieving a balance between heat dissipation efficiency and electrochemical stability of the electrode 2131.

[0140] D2mm can be any value that satisfies 3.5mm, 4mm, 5mm, 10mm, 12mm, 15mm, etc., where 3.5mm≤D2mm≤15mm.

[0141] In some implementations, see Figure 11 The battery pack also includes a conductive busbar 5, and the individual battery 21 also includes a terminal post 215 disposed on the cover plate 212. One end of the terminal post 215 is electrically connected to the battery cell 213, and the other end is welded to the conductive busbar 5. The terminal post 215 and the conductive busbar 5 are welded to form a first welding surface 200. Along the third direction Z, the distance between the heat exchange plate 3 and the first welding surface 200 is D3mm, which satisfies: 2mm≤D3mm≤3.5mm.

[0142] The first welding surface 200 (the welding area between the pole 215 and the conductive busbar 5) is prone to heat generation during fast charging. By limiting D3 to 2mm≤D3mm≤3.5mm, we can avoid D3 being too small (<2mm) causing temperature fluctuations in the heat exchange plate 3 that affect the welding surface, and also prevent D3 being too large (>3.5mm) that lengthens the heat dissipation path. This ensures efficient heat dissipation from the welding surface, avoids high-temperature softening of the solder and cracking, and guarantees connection reliability.

[0143] D3mm can be any value that satisfies 2mm≤D3mm≤3.5mm, such as 2mm, 2.5mm, 3mm, 3.5mm, etc.

[0144] In some implementations, see Figure 12 The housing 211 includes a thickened area 2112 and a non-thickened area 2113 that are connected to each other. The thickened area 2112 is located near the cover plate 212. The thickness of the thickened area 2112 is E5, and the thickness of the non-thickened area 2113 is E6, satisfying: 0.05mm≤E5mm-E6mm≤1.5mm.

[0145] By limiting the thickness difference E5-E6 between the thickened area 2112 and the non-thickened area 2113 to within the range of 0.05mm to 1.5mm, the structural strength and thermal interface stability of the casing 211 in the welding area of ​​the cover plate 212 are optimized, thereby improving the vibration resistance, heat conduction efficiency, and manufacturing economy of the battery pack. Specifically, if E5-E6 is too small (<0.05mm), the strength of the thickened area 2112 is insufficient, and the welding point of the cover plate 212 (the area of ​​the first weld line 100) is prone to microcracks or loosening under vibration or thermal cycling conditions, resulting in thermal interface pressure imbalance and increased thermal resistance; if E5-E6 is too large (>1.5mm), the excessive thickening of the thickened area 2112 increases the weight and material cost of the casing 211.

[0146] In some implementations, see Figure 13 and Figure 14The heat exchange plate 3 and the base plate 11 are spaced apart, and the bottom surface of the single cell 21 is connected to the base plate 11; along the third direction Z, the distance between the heat exchange plate 3 and the base plate 11 is D6mm, which satisfies: 0.5mm≤D6mm≤15mm.

[0147] By limiting the distance D6 between the heat exchange plate 3 and the base plate 11 in the third direction Z (height direction) to within the range of 0.5mm to 15mm, the mechanical structural stability and thermal management synergy of the battery pack can be optimized. Specifically, if D6 is too small (<0.5mm): the distance between the heat exchange plate 3 and the base plate 11 is too close, and they are prone to contact and collision during vibration or assembly, resulting in deformation of the heat exchange plate 3, damage to the base plate 11, or local thermal interface pressure imbalance, which will increase thermal resistance and cause the risk of thermal short circuit; if D6 is too large (>15mm): the distance between the heat exchange plate 3 and the base plate 11 is too large, making the overall structure of the battery pack loose, and the heat exchange plate 3 is prone to displacement or suspension under vibration conditions, which will disrupt the continuity of the heat conduction path, resulting in heat not being efficiently dissipated through the heat exchange plate 3, and aggravating the heat accumulation in the bottom area of ​​the battery pack.

[0148] D6mm can be any value that satisfies 0.5mm ≤ D6mm ≤ 15mm, such as 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 5mm, 10mm, 15mm, etc.

[0149] It should be noted that in the battery pack described in this application, the heat exchange plate and the base plate are spaced apart along the third direction Z (i.e., the thickness direction of the base plate 11), and there is no direct contact between them. This spacing is intended to prevent the formation of a conductive path due to direct contact or vibration between the heat exchange plate and the base plate, which may both be made of metal, during assembly or use. This eliminates the potential risk of electrical short circuits and prevents electrochemical corrosion caused by potential differences, thereby improving the overall safety of the battery pack. Especially when both the heat exchange plate and the base plate are made of highly conductive metal materials such as aluminum alloy or stainless steel, if they are directly attached, accidental conduction can easily occur under conditions of insulation layer damage, condensation accumulation, or long-term vibration, which can affect the insulation performance of the battery system and even cause safety accidents. The above-mentioned spacing can be achieved in various ways. On the one hand, a direct spacing method can be used, in which the heat exchange plate is suspended above the base plate by connecting to the frame, indirectly fixing to the battery pack, or using a cantilever support structure, leaving an air gap between the heat exchange plate and the base plate, which is denoted as D6. Alternatively, this spacing can be achieved and maintained by installing an isolation element: an isolation element made of electrically insulating material (such as plastic pads, rubber gaskets, epoxy resin supports, engineering plastic clips, or injection-molded positioning posts) is placed between the heat exchange plate and the base plate. This not only ensures that D6 is within a reasonable range but also provides support, buffering, and positioning. In this case, the heat exchange plate and the base plate can be indirectly fixedly connected through this isolation element, ensuring both structural stability and reliable electrical isolation.

[0150] The insulating component is preferably made of materials with good electrical insulation, high and low temperature resistance, mechanical strength and long-term aging stability, such as polyamide (PA66, with or without glass fiber), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), silicone or thermoplastic elastomer (TPE).

[0151] It should be noted that the heat exchange plate 3 does not necessarily have to be directly connected to the base plate 11; it can be connected only to the frame, shell or other non-conductive structure, as long as it is kept at a distance from the base plate in the third direction.

[0152] The following are the relevant testing methods:

[0153] A test method for solder wire breakage: The test object is a battery pack. For each embodiment and comparative example, 200 square-shell lithium-ion cells are combined with a heat exchange plate. In the heat exchange plate, the first side of the cell casing is connected to the heat exchange plate. After installation, the cover is closed and fixed.

[0154] The battery pack is kept at room temperature (25°C) and charged to the upper limit voltage of each individual cell at a constant current rate of 1C. Then it is charged at a constant voltage until the current drops to 0.05C. After resting for 30 minutes, it is discharged to the lower limit voltage at a constant current rate of 1C and then rested for 30 minutes. This is one charge-discharge cycle.

[0155] For different battery systems, the upper and lower voltage limits need to be adjusted accordingly: Lithium iron phosphate (LFP) system - upper voltage 3.65V, lower voltage 2.5V; ternary lithium (NCM) system - upper voltage 4.25V, lower voltage 2.5V; lithium manganese iron phosphate (LFMP) system - upper voltage 4.25V, lower voltage 2.5V; lithium nickel manganese oxide system - upper voltage 4.8V, lower voltage 3.5V.

[0156] After performing 100 charge-discharge cycles on a single battery cell, the test object was mounted on a vibration table according to the requirements of GB / T2423.43. The test procedure was carried out according to the provisions of GB / T2423.56. Random and fixed-frequency vibration loads were applied in each direction, and the loading sequence should preferably be random z-axis, fixed-frequency z-axis, random y-axis, fixed-frequency y-axis, random x-axis, fixed-frequency x-axis (the direction of the line connecting the front and rear of the battery pack is the x-axis direction, and the other horizontal direction perpendicular to the x-axis direction is the y-axis direction). The vibration frequency, power spectral density (PSD), vibration time, etc. are shown in Table 1 below.

[0157] Table 1

[0158]

[0159] After the test, the battery pack cover was removed, and the weld lines between the casing and the cover plate of each individual cell were observed to see if they were broken. The total number of individual cells with broken weld lines was divided by the total number of individual cells tested to obtain the weld line breakage rate. A weld line breakage rate greater than or equal to 5% was considered unqualified, while a rate less than 5% was considered qualified.

[0160] A method for measuring the heat dissipation effect of a single battery cell: The test object is a battery pack. For each embodiment and comparative example, 200 lithium-ion prismatic batteries are combined with a heat exchange plate. The prismatic batteries are discharged at a rate of 0.33C to the lower limit voltage and placed in the battery compartment of the battery pack. Conductive busbars are welded to the terminals of the prismatic batteries. An NTC (Negative Temperature Coefficient) thermistor is attached to the same position on the top surface of each prismatic battery, and the temperature measured on the NTC thermistor is collected in real time through a data acquisition line. After installation, the cover is closed and fixed.

[0161] Different cell systems require corresponding adjustments to their upper and lower voltage limits: LFP (LiFePO4, lithium iron phosphate) - upper limit voltage 3.65V, lower limit voltage 2.5V; NCM (lithium nickel cobalt manganese oxide) - upper limit voltage 4.25V, lower limit voltage 2.5V; LFMP (lithium manganese iron phosphate) - upper limit voltage 4.25V, lower limit voltage 2.5V; lithium nickel manganese oxide - upper limit voltage 4.8V, lower limit voltage 3.5V.

[0162] The ambient temperature was set to room temperature (25℃). The individual cells in the battery pack were charged at a rate of 1C to the upper limit voltage. The battery temperature measured by each NTC thermistor was recorded. The highest temperature measured was used as an indicator of the heat dissipation effect of the individual cells in the battery pack. A maximum battery temperature of less than or equal to 60℃ was considered acceptable, while a maximum temperature greater than 60℃ was considered unacceptable.

[0163] Using the test method described above, the units for d, h, x, and k in Table 2 are all millimeters (mm), and the results are shown in Table 2 below:

[0164] Table 2

[0165]

[0166] As shown in Table 2, Examples 1-12 satisfy 25≤x*k / (S1 / S)≤500, while Comparative Examples 1-3 do not satisfy 25≤x*k / (S1 / S)≤500. The wire breakage ratio of Examples 1-12 is qualified, while the wire breakage ratio of Comparative Examples 1-2 is unqualified. That is, the wire breakage of Examples 1-12 is significantly better than that of Comparative Examples 1-2. Examples 1-12 satisfy 0.72≤S1 / S≤0.96, while Comparative Example 3 does not satisfy 0.72≤S1 / S≤0.96. The highest battery temperature of Examples 1-12 is 57.6℃, which is the same as that of Example 8, while the highest battery temperature of Comparative Example 3 is 66.4℃. The heat dissipation effect of the single cell of Examples 1-12 is significantly better than that of Comparative Example 3.

[0167] Secondly, this application also provides an electrical device, which includes the battery pack of any of the above.

[0168] Electrical devices can include, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Among them, electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0169] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of this application, and these improvements and substitutions should also be considered within the scope of protection of this application.

Claims

1. A battery pack, characterized in that, include: The box body includes a bottom plate and a frame that are connected to each other, the bottom plate and the frame forming an accommodating space, and the thickness direction of the bottom plate is the third direction; A heat exchange plate has a heat exchange channel inside for passing a heat exchange medium. The heat exchange plate is disposed in the accommodating space and is connected to the bottom plate and / or the frame. The length direction of the heat exchange plate is a first direction. Thermal conductive components; A battery pack is disposed on the upper part of the base plate. The battery pack includes a battery array consisting of at least two individual cells arranged along the first direction, and the individual cells are connected to the base plate. Each individual cell includes a casing, a cover plate, and a cell. The casing includes at least one opening, and the cover plate is welded to the opening and forms a first weld line. The casing and the cover plate form a receiving cavity, and the cell is disposed in the receiving cavity. The cell includes an electrode. A first side of the casing is perpendicular to the base plate and connected to the heat exchange plate through the heat-conducting element. Wherein, the first direction, the third direction, and the second direction are mutually perpendicular; along the second direction, the distance between the heat exchange plate and the first bonding wire is d mm; along the third direction, the distance between the heat exchange plate and the first bonding wire is h mm; x = d + h; along the third direction, the distance between the electrode and the first bonding wire is k mm; the area overlapping between the orthographic projection of a single battery array along the second direction and the projection of the heat exchange plate is S1 mm. 2 The area of ​​a single heat exchange plate facing the first side is S mm. 2 The following condition must be met: 25 ≤ x*k / (S1 / S) ≤ 500. 0.3mm≤dmm≤2.6mm, 5mm≤hmm≤25mm, 3.5mm≤kmm≤15mm; 0.72≤S1 / S≤0.

96.

2. The battery pack according to claim 1, characterized in that, The heat exchange plate and the battery array form a first opposing region. Within the first region, along a third direction, the top surface of the heat exchange plate is lower than the top surface of the cover plate.

3. The battery pack according to claim 2, characterized in that, Along the third direction, the end of the electrode near the cover plate is the first electrode end, which is located between the top surface of the cover plate and the top surface of the heat exchange plate.

4. The battery pack according to claim 3, characterized in that, Along the third direction, the distance between the first electrode end and the top surface of the heat exchange plate is D1mm, which satisfies: 0mm≤D1mm≤15mm.

5. The battery pack according to claim 2, characterized in that, Along the third direction, the end of the electrode near the cover plate is the first electrode end, the top surface of the heat exchange plate is located between the first electrode end and the top surface of the cover plate, and the distance between the top surface of the heat exchange plate and the first electrode end is D2mm, satisfying: 3.5mm≤D2mm≤15mm.

6. The battery pack according to claim 1, characterized in that, The single battery cell also includes an electrical connector. The battery cell includes a tab portion and a body portion. The tab portion is led out from at least one end of the body portion. The electrical connector is electrically connected to the tab portion. Along the third direction, at least a portion of the electrical connector is located between the top surface of the heat exchange plate and the first weld line.

7. The battery pack according to claim 6, characterized in that, Along the length direction of the cover plate, the length dimension of the cover plate is L1mm, and the dimension of the electrical connector is L2mm, satisfying: 0.15≤L2 / L1≤0.

5.

8. The battery pack according to claim 1, characterized in that, It also includes a conductive busbar, and the single cell also includes an electrode post disposed on the cover plate. One end of the electrode post is electrically connected to the cell, and the other end is welded to the conductive busbar. The electrode post and the conductive busbar are welded to form a first welding surface. Along the third direction, the distance between the heat exchange plate and the first welding surface is D3mm, which satisfies: 2mm≤D3mm≤3.5mm.

9. The battery pack according to claim 1, characterized in that, The heat exchange channel extends along the first direction; along the third direction, the distance between the heat exchange channel closest to the first weld line and the first weld line in the heat exchange plate is D4mm, satisfying: 5.3mm≤D4mm≤28mm.

10. The battery pack according to claim 9, characterized in that, Along the third direction, within the heat exchange plate, there is a first partition wall between two adjacent heat exchange channels. The distance between the first partition wall closest to the first weld line and the first weld line within the heat exchange plate is D5mm, satisfying: 8mm≤D5mm≤30mm.

11. The battery pack according to any one of claims 1-10, characterized in that, The heat exchange channel of the heat exchange plate is formed by multiple structural walls, and the wall thickness of the structural wall is E1mm, which satisfies: 0.3mm≤E1mm≤3mm.

12. The battery pack according to any one of claims 1-10, characterized in that, The heat exchange plate is spaced apart from the base plate, and the bottom surface of the individual battery is connected to the base plate; along the third direction, the distance between the heat exchange plate and the base plate is D6mm, which satisfies: 0.5mm≤D6mm≤15mm.

13. The battery pack according to any one of claims 1-10, characterized in that, The thermally conductive component is a thermally conductive adhesive layer, and the heat exchange plate is connected to the first side of the housing through the thermally conductive adhesive layer; the thickness of the thermally conductive adhesive layer is E2mm, satisfying: 0.5mm≤E2mm≤2.5mm.

14. The battery pack according to claim 13, characterized in that, The outer surface of the battery cell is wrapped with an insulating film, the thickness of which is E3μm, satisfying: 50μm≤E3μm≤110μm.

15. The battery pack according to any one of claims 1-10, characterized in that, The housing includes two opposing first sides and two opposing second sides, the first sides and the second sides being arranged perpendicular to the base plate, the first sides being larger than the second sides, satisfying: 10mm≤xmm≤27.6mm.

16. The battery pack according to claim 1, characterized in that, The housing includes two opposing first sides and two opposing second sides, the first sides and the second sides being arranged perpendicular to the base plate, the first sides being smaller than the second sides, satisfying: 0.72≤S1 / S≤0.

96.

17. The battery pack according to claim 15, characterized in that, The heat exchange plate has multiple heat exchange channels spaced apart along the third direction; along the third direction, the distance between two adjacent heat exchange channels is D7mm, satisfying: 0.3mm≤D7mm≤3mm.

18. The battery pack according to any one of claims 1-10, characterized in that, The thickness of the heat exchange plate is E4mm, which satisfies the following condition: 2.5mm≤E4mm≤25mm.

19. The battery pack according to claim 1, characterized in that, Along the first direction, at least one end of the heat exchange plate extends beyond the end of the battery pack, and the dimension of the heat exchange plate extending beyond the end of the battery pack is Fmm, satisfying: 25mm≤Fmm≤70mm.

20. The battery pack according to any one of claims 1-10, characterized in that, The penetration direction of the first weld wire is perpendicular to the top surface of the cover plate, and the penetration dimension of the first weld wire is G1, which satisfies: 1mm≤G1mm≤4.5mm.

21. The battery pack according to any one of claims 1-10, characterized in that, The penetration direction of the first weld wire is parallel to the top surface of the cover plate, and the penetration dimension of the first weld wire is G2mm, which satisfies: 1mm≤G2mm≤2.5mm.

22. The battery pack according to any one of claims 1-10, characterized in that, 28800mm 2 ≤S1mm 2 ≤274560mm 2 、40000mm 2 ≤Smm 2 ≤286000mm 2 。 23. The battery pack according to any one of claims 1-10, characterized in that, 50≤x*k / (S1 / S)≤400.

24. The battery pack according to any one of claims 1-10, characterized in that, The cover plate is disposed on the end face of the single cell away from the bottom plate, and the first welding line welds the cover plate and the housing together, satisfying: 5mm≤hmm≤20mm.

25. The battery pack according to claim 1, characterized in that, The single battery cell also includes an electrode post, which is disposed on the side of the casing away from the cover plate and connected to the cell; satisfying: 4.5mm≤kmm≤15mm.

26. The battery pack according to claim 1, characterized in that, The housing includes interconnected thickened and non-thickened areas. The thickened area is located close to the cover plate. The thickness of the thickened area is E5, and the thickness of the non-thickened area is E6, satisfying the condition: 0.05mm≤E5mm-E6mm≤1.5mm.

27. An electrical appliance, characterized in that, Includes the battery pack as described in any one of claims 1-26.

Images