Battery module, battery pack, battery cluster and energy storage device

Abstract

The application discloses a battery module, a battery pack, a battery cluster and an energy storage device, and belongs to the technical field of batteries. The battery module comprises a current collecting piece and a plurality of battery cells. The plurality of battery cells are arranged in sequence along the thickness direction thereof. Each battery cell comprises a battery cell body and a tab which are electrically connected. The current collecting piece comprises alternating connection sections and transition sections. Each connection section is connected with each tab. Adjacent connection sections and transition sections are arranged at an included angle. When two adjacent battery cells are charged and discharged and the distance between the two tabs changes, the transition section can rotate relative to the connection section. By allowing the transition section to rotate relative to the connection section, the change in the distance between the tabs caused by the "breathing effect" of the battery cells can be adapted to. The tabs or the current collecting piece are prevented from being broken due to the change in the distance between the tabs. Meanwhile, the connection resistance is maintained stable, and the structural reliability and electrical safety of the battery module under long-term cycle working conditions are improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more particularly to a battery module, battery pack, battery cluster, and energy storage device. Background Technology

[0002] Pouch batteries are widely used in new energy vehicles and energy storage systems due to their advantages such as high energy density, good safety, and flexible design. In the energy storage field, to meet the demands of high capacity and high power output, a large number of pouch cells are typically integrated in parallel to form battery modules. In this process, reliable electrical connections between the cell tabs are crucial to determining the module's performance, lifespan, and safety.

[0003] However, during charge-discharge cycles, the internal electrochemical reactions of pouch cells cause thickness changes, known as the "breathing effect." This continuous expansion and contraction creates repeated mechanical stress on the tab connection points. Traditional rigid connection methods struggle to effectively adapt to this deformation, easily leading to connection point fatigue, increased resistance, and even tab tearing, thus affecting module cycle life and posing a high risk of thermal runaway. Utility Model Content

[0004] This application provides a battery module, battery pack, battery cluster, and energy storage device to at least partially solve the above-mentioned technical problems.

[0005] To achieve the above objectives, according to a first aspect of this application, a battery module is provided, including a busbar and a plurality of battery cells, wherein the plurality of battery cells are arranged sequentially along their thickness direction, and each battery cell includes an electrically connected cell body and a tab; the busbar includes alternately arranged connecting sections and transition sections, each connecting section being connected to each tab, and adjacent connecting sections and transition sections being arranged at an angle; wherein, when two adjacent battery cells are charged and discharged and the distance between the two tabs changes, the transition section is rotatable relative to the connecting section.

[0006] In some embodiments, by allowing the transition section to rotate relative to the connecting section, the spacing between the tabs can be adapted to the "breathing effect" of the battery cell, preventing the tabs or busbars from breaking due to the spacing between the tabs, while maintaining stable connection resistance and improving the structural reliability and electrical safety of the battery module under long-term cycle conditions.

[0007] In some embodiments, by using continuously bent busbars instead of traditional flat busbars, the welding process is standardized and universalized. It allows the use of general-purpose metal strips formed through continuous bending, eliminating reliance on customized molds and specialized tooling. This simplifies welding positioning, improves welding efficiency, and reduces production costs and process complexity. Furthermore, the universal busbars are compatible with battery modules of different capacities, supporting rapid changeovers and flexible production lines, significantly shortening product delivery cycles and enabling quick response to market demands.

[0008] In some embodiments, by employing flexible busbars, the weight ratio of the busbars is reduced while ensuring electrical performance, thereby improving the weight energy density and packing efficiency of the battery module. This is suitable for battery modules with high discharge rate performance and high energy density.

[0009] Optionally, the tab includes a first part and a second part. The first part is connected to the cell body, and the second part protrudes from the cell body and bends toward one side of the cell body in the thickness direction. The connecting segment is connected to the second part. When two adjacent cells are charged and discharged and the distance between the two tabs changes, the second part can rotate toward the other side of the cell body in the thickness direction.

[0010] In some embodiments, by setting the tab as a combination of a first part and a second part, and with the connecting segment, a flexible buffer mechanism is formed on the tab itself. This allows the tab to absorb mechanical stress through the rotation of the second part and the elastic deformation of the first part when the cell thickness changes. This effectively reduces stress concentration on the tab, reduces the risk of tab breakage, and ensures the stability of the connection point between the busbar and the tab, thereby improving the cycle life and safety performance of the battery module.

[0011] Optionally, there is an arc transition between the connecting segment and the transition segment; and / or, there is an arc transition between the first part and the second part.

[0012] In some embodiments, the use of rounded transitions between the connecting section and the transition section, and / or between the first part and the second part, significantly improves the stress distribution characteristics of the structure. Rounded transitions effectively eliminate stress concentration at sharp corners, improve the fatigue resistance of the busbar and tabs during repeated deformation, reduce the risk of microcracks caused by stress concentration, and simultaneously promote uniform current distribution, reducing the possibility of localized overheating, thereby comprehensively improving the mechanical reliability and electrical safety of the battery module.

[0013] Optionally, the battery module further includes an insulating component disposed between the second part and the cell body.

[0014] In some embodiments, by setting an insulating component between the second part and the cell body, the outer packaging of the aluminum-plastic film of the cell is protected, preventing thermal damage and mechanical indentation that may occur during the welding of the tabs and busbars. Furthermore, throughout the entire life cycle of the battery module, it continuously prevents scratches, abrasions and other damage to the aluminum-plastic film caused by repeated rotation of the tabs, reduces safety hazards such as short circuits and leakage caused by mechanical damage, and improves the long-term reliability and safety of the battery module.

[0015] Optionally, the insulating element and the battery cell body are bonded together.

[0016] In some embodiments, the insulating component is fixed to the cell body by adhesive bonding, which ensures the positional stability of the insulating component throughout the entire life cycle of the battery module, making the insulating component and the cell body fit tightly together, preventing protection failure caused by the displacement of the insulating component, and simplifying the assembly process and increasing production efficiency.

[0017] Optionally, the included angle between the connecting segment and the transition segment is no greater than 90°.

[0018] In some embodiments, by limiting the angle between the connecting section and the transition section to no more than 90°, the deformation characteristics of the busbar are optimized, so that the busbar has a larger deformation stroke in the cell thickness direction, which can more effectively adapt to the changes in the tab spacing caused by the "breathing effect", while preventing stress concentration caused by excessive angle, thereby improving the fatigue resistance of the busbar and the cycle life of the battery module.

[0019] Optionally, the busbar includes a metal strip.

[0020] In some embodiments, by using metal strips as the base material for the busbars, the design of battery modules is made universal, allowing metal strips of the same specification to be adapted to various battery modules through different bending schemes, reducing the types of parts and mold investment; at the same time, standardized material selection simplifies supply chain management, improves production efficiency, facilitates rapid changeover and large-scale production of battery production lines, and effectively reduces overall manufacturing costs.

[0021] Optionally, the busbar includes a nickel strip, a copper strip, or a copper-plated nickel strip.

[0022] In some embodiments, nickel strip, copper strip, or nickel-plated copper strip can be flexibly selected as the bus material according to electrical performance and process requirements. Nickel strip can ensure welding quality and environmental adaptability, and is suitable for applications with high corrosion resistance requirements; copper strip has low resistance in the conductive circuit, and is suitable for high-rate charging and discharging; nickel-plated copper strip has good conductivity and can ensure the welding stability of copper and aluminum tabs.

[0023] Optionally, the busbar is welded to the tab.

[0024] In some embodiments, the busbar and the tab are fixed by welding, forming a connection with excellent conductivity and mechanical strength. The contact resistance is low, the connection reliability is high, and it can withstand the thermal shock when a large current passes through and the mechanical stress caused by the cell breathing effect. At the same time, the welding process is highly efficient and easy to automate, making it suitable for the large-scale production of battery modules and effectively ensuring the electrical safety and long-term reliability of the battery module.

[0025] Optionally, the battery module further includes at least one lead wire connected to the busbar.

[0026] In some embodiments, the flexible configuration of single-point or multi-point leads allows the battery module to adapt to different discharge rates. A single-point lead design simplifies the structure, reduces costs, and is suitable for cost-sensitive low-rate applications. A multi-point evenly distributed lead design reduces the current load on the busbars through current shunting, improves heat dissipation, and ensures electrical safety and thermal stability during high-rate discharge, making the battery module suitable for various application scenarios.

[0027] Optionally, the battery module includes two busbars, one of which is connected to the positive terminal of each of the battery cells, and the other of which is connected to the negative terminal of each of the battery cells.

[0028] In some embodiments, by connecting the battery module cells in parallel and combining them with the flexible busbar structure, synergistic optimization of electrical and mechanical performance is achieved. Electrically, this solution utilizes the low impedance characteristics of the busbar to achieve natural voltage equalization among the cells and provides extremely low total circuit impedance, thereby improving the high-rate discharge capability of the battery module. Mechanically, the flexible connection allows each cell to cope with the "breathing effect" relatively independently, avoiding module-level cumulative stress caused by the deformation of a single cell and improving the overall structural reliability.

[0029] According to a second aspect of this application, a battery pack is provided, which includes the battery module described above. This battery pack possesses all the beneficial effects of the battery module described above, which will not be elaborated further here.

[0030] According to a third aspect of this application, a battery cluster is provided, which includes the aforementioned battery module or battery pack. This battery cluster possesses all the beneficial effects of the aforementioned battery module or battery pack, which will not be elaborated further herein.

[0031] According to a fourth aspect of this application, an energy storage device is provided, comprising the aforementioned battery module, battery pack, or battery cluster. This energy storage device possesses all the beneficial effects of the aforementioned battery module, battery pack, or battery cluster, which will not be elaborated further herein.

[0032] In the battery module of this application embodiment, the flexible design with a variable angle between the connecting section and the transition section in the busbar enables the entire electrical connection structure to adaptively absorb and compensate for the thickness deformation caused by the "breathing effect" of the battery cell during charging and discharging. This effectively alleviates the mechanical stress concentration at the tab connection point, reduces the risk of tab breakage due to fatigue or increased connection resistance, and thus improves the connection reliability, service life and safety of the battery module under long-term charge and discharge cycle conditions.

[0033] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] To gain a more complete understanding of this application and its beneficial effects, the following description will be provided in conjunction with the accompanying drawings, wherein the same reference numerals in the following description denote the same parts.

[0035] Figure 1 This is a side view of the battery module provided in an exemplary embodiment of this application; Figure 2 This is a first-view structural diagram of the first assembly process of the battery module provided in an exemplary embodiment of this application; Figure 3 yes Figure 2 An enlarged schematic diagram of part A in the middle; Figure 4 yes Figure 1 The exploded view of the battery module structure provided in the image; Figure 5 yes Figure 2 A second-view structural diagram of the first assembly process of the battery module provided in the image; Figure 6 This is a first-view structural diagram of the second assembly process of the battery module provided in an exemplary embodiment of this application; Figure 7 yes Figure 6 Enlarged schematic diagram of part B in the middle; Figure 8 This is a schematic diagram of the third assembly process of the battery module provided in an exemplary embodiment of this application; Figure 9 yes Figure 6 A second-view structural schematic diagram of the second assembly process of the provided battery module; Figure 10 yes Figure 1 A first-view 3D structural diagram of the battery module provided in the image; Figure 11 yes Figure 1 The second-view stereoscopic structural diagram of the battery module provided in the image.

[0036] Explanation of reference numerals in the attached figures: 1. Battery cell; 11. Battery cell body; 12. Electrode; 121. First part; 122. Second part; 2. Busbar; 21. Connecting section; 22. Transition section; 3. Insulating components. Detailed Implementation

[0037] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the protection scope of this application.

[0038] According to the first aspect of this application, referring to Figure 1 This application provides a battery module, including a busbar 2 and multiple battery cells 1. The multiple battery cells 1 are arranged sequentially along their thickness direction. Each battery cell 1 includes a battery cell body 11 and a tab 12 that are electrically connected. The busbar 2 includes alternating connecting sections 21 and transition sections 22. Each connecting section 21 is connected to each tab 12. Adjacent connecting sections 21 and transition sections 22 are arranged at an angle. When two adjacent battery cells 1 are charged and discharged and the distance between the two tabs 12 changes, the transition section 22 can rotate relative to the connecting section 21.

[0039] It is understood that connecting segment 21 specifically refers to the straight portion directly and fixedly connected to the tab 12 of cell 1, while transition segment 22 is the portion connecting adjacent connecting segments 21. The included angle between connecting segment 21 and transition segment 22 includes, but is not limited to, acute angles or right angles, and can be achieved through "Z", "U" shaped, or wavy continuous bending structures. Rotation refers to the relative movement between the transition segment 22 and connecting segment 21, where the connection point is flexible and can deform, thereby changing the size of the included angle.

[0040] During charging and discharging, the pouch cell 1 exhibits a "breathing effect." Due to the periodic volume changes of the active material caused by the insertion and extraction of lithium ions between the positive and negative electrodes, this ultimately manifests as expansion and contraction in the thickness direction of cell 1. For example, when cell 1 expands in thickness during charging, the distance between adjacent cell tabs 12 increases, causing the transition section 22 to bend relative to the connecting section 21, increasing the angle between them and thus absorbing tensile stress. When cell 1 shrinks in thickness after discharging, the distance between adjacent tabs 12 decreases, and the transition section 22 recovers under its own elasticity or external constraints, correspondingly reducing the angle between it and the connecting section 21 to alleviate compressive stress.

[0041] In some embodiments, by allowing the transition section 22 to rotate relative to the connecting section 21, the spacing between the tabs 12 can be adapted to the "breathing effect" of the cell 1, preventing the tabs 12 or the busbar 2 from breaking due to the spacing between the tabs 12, while maintaining stable connection resistance and improving the structural reliability and electrical safety of the battery module under long-term cycle conditions.

[0042] In some embodiments, by using a continuously bent busbar 2 instead of a traditional flat busbar, the welding process is standardized and universalized. It can be formed using general-purpose metal strips through a continuous bending process, eliminating the reliance on customized molds and special tooling. This simplifies welding positioning, improves welding efficiency, and reduces production costs and process complexity. Simultaneously, the universal busbar 2 is compatible with battery modules of different capacities, supporting rapid changeovers and flexible production lines, significantly shortening product delivery cycles and enabling rapid response to market demands.

[0043] In some embodiments, by employing a flexible busbar 2, the weight ratio of the busbar 2 is reduced while ensuring electrical performance, thereby improving the weight energy density and packing efficiency of the battery module, which is suitable for battery modules with high discharge performance and high energy density.

[0044] Reference Figure 2 and Figure 3 In some embodiments, the tab 12 includes a first part 121 and a second part 122. The first part 121 is connected to the cell body 11, and the second part 122 protrudes from the cell body 11 and bends to one side in the thickness direction of the cell body 11. The connecting section 21 is connected to the second part 122. When two adjacent cells 1 are charged and discharged and the distance between the two tabs 12 changes, the second part 122 can rotate to the other side in the thickness direction of the cell body 11.

[0045] It is understood that the first part 121 refers to the base section of the tab 12 extending from the edge of the cell body 11, and the second part 122 refers to the cantilever section that bends and extends from the end of the first part 121 towards the thickness direction of the cell body 11. The bending of the second part 122 to one side can be an arc bend, an angle bend, or other continuous bending forms, and the angle between the first part 121 and the second part 122 ranges from 30° to 180°. The connection method between the connecting section 21 and the second part 122 includes fixed connection methods such as welding, riveting, or bolting. The second part 122 rotates in the opposite direction to the bending direction.

[0046] When the thickness of cell 1 expands during charging, the distance between the tabs 12 of adjacent cells 1 increases, and the connecting segment 21 exerts a tensile force on the second part 122, causing the second part 122 to rotate away from the cell body 11. At the same time, the first part 121 undergoes adaptive elastic deformation. When the thickness of cell 1 contracts during discharging, the distance between the tabs 12 of adjacent cells 1 decreases, the force exerted by the connecting segment 21 on the second part 122 decreases, and the second part 122 rotates back towards the cell body 11 under its own elastic restoring force. The first part 121 then returns to its original shape.

[0047] In some embodiments, by setting the tab 12 as a combination of the first part 121 and the second part 122, and in conjunction with the connecting section 21, a flexible buffer mechanism is formed on the tab 12 itself. This allows the tab 12 to absorb mechanical stress through the rotation of the second part 122 and the elastic deformation of the first part 121 when the thickness of the cell 1 changes. This effectively reduces stress concentration on the tab 12, reduces the risk of tab 12 breakage, and ensures the stability of the connection point between the busbar 2 and the tab 12, thereby improving the cycle life and safety performance of the battery module.

[0048] Reference Figure 1 and Figure 3 In some embodiments, there is an arc transition between the connecting segment 21 and the transition segment 22; and / or, there is an arc transition between the first portion 121 and the second portion 122.

[0049] Understandably, a circular arc transition refers to the use of an arc-shaped bend design at the connection between connecting segment 21 and transition segment 22 to avoid sharp corners; similarly, an arc-shaped bend design is also used at the connection between the first part 121 and the second part 122 of the tab 12. The radius of curvature of the circular arc transition can be designed according to material properties, current carrying capacity requirements, and deformation requirements. The circular arc transition can be a continuous uniform arc or a composite arc composed of multiple arcs with different radii of curvature.

[0050] During the charging and discharging process of cell 1, when the connecting section 21 and the transition section 22 adopt an arc transition, the stress is effectively dispersed in the arc-shaped area, avoiding stress concentration at sharp corners and making the relative rotation of the transition section 22 smoother. When the first part 121 and the second part 122 of the tab 12 adopt an arc transition, this arc-shaped area, as the main area of ​​elastic deformation, can evenly distribute bending stress when the second part 122 rotates, improving the fatigue resistance of the tab 12.

[0051] In some embodiments, the stress distribution characteristics of the structure are significantly improved by using a rounded transition design between the connecting section 21 and the transition section 22 and / or between the first part 121 and the second part 122. The rounded transition effectively eliminates stress concentration at sharp corners, improves the fatigue resistance of the busbar 2 and the tab 12 during repeated deformation, reduces the risk of microcracks in the material due to stress concentration, and at the same time, the rounded design is conducive to the uniform distribution of current and reduces the possibility of local overheating, thereby comprehensively improving the mechanical reliability and electrical safety of the battery module.

[0052] Reference Figure 4 and Figure 5 In some embodiments, the battery module further includes an insulating element 3 disposed between the second part 122 and the cell body 11.

[0053] Understandably, the insulating component 3 is a separating element located between the second part 122 and the outer packaging (typically aluminum-plastic film) of the cell body 11. This insulating component 3 can be made of polyimide film, PET sheet, or other polymer insulating materials, possessing good insulation, mechanical strength, and abrasion resistance. Its location covers the projected area of ​​the second part 122 on the cell body 11, and it is fixed to the surface of the cell body 11 by adhesive bonding or snap-fitting.

[0054] When the second part 122 rotates away from the cell body 11, the insulating component 3 acts as a buffer layer to prevent the welding points of the tabs 12 or any sharp edges from directly scratching or pressing the surface of the aluminum-plastic film. When the second part 122 rotates towards the cell body 11, the insulating component 3 also serves as an isolation layer.

[0055] In some embodiments, by providing an insulating element 3 between the second part 122 and the cell body 11, the aluminum-plastic film outer packaging of the cell 1 is protected, preventing thermal damage and mechanical indentation that may occur during the welding process of the tab 12 and the busbar 2. Furthermore, throughout the entire life cycle of the battery module, it continuously prevents scratches, abrasions, and other damage to the aluminum-plastic film caused by repeated rotation of the tab 12, reducing safety hazards such as short circuits and leakage caused by mechanical damage, and improving the long-term reliability and safety of the battery module.

[0056] In some embodiments, the insulating element 3 and the battery cell body 11 are bonded together.

[0057] Understandably, the insulating component 3 is fixedly connected to the outer surface of the aluminum-plastic film of the battery cell body 11 through an adhesive layer. This adhesive can be an acrylic pressure-sensitive adhesive, epoxy resin adhesive, or hot melt adhesive, possessing high bonding strength, electrical insulation, and long-term aging resistance. The adhesive area can cover all or part of the bottom surface of the insulating component 3, forming a continuous or discontinuous adhesive layer to ensure that the insulating component 3 maintains stable positioning during the rotation of the tab 12.

[0058] When the second part 122 rotates and may come into contact with the insulating part 3, the adhesive connection ensures that the insulating part 3 always remains in the preset protective position and will not be displaced due to the pushing or friction of the tab 12, thereby maintaining stable and reliable isolation.

[0059] In some embodiments, the insulating component 3 is fixed to the cell body 11 by adhesive bonding, which ensures the positional stability of the insulating component 3 throughout the entire life cycle of the battery module, makes the insulating component 3 and the cell body 11 fit tightly, prevents protection failure caused by displacement of the insulating component 3, and simplifies the assembly process and increases production efficiency.

[0060] Reference Figure 1 , Figure 6 and Figure 7 In some embodiments, the included angle ∠1 between the connecting segment 21 and the transition segment 22 is not greater than 90°.

[0061] It is understood that the internal angle formed between the connecting section 21 and the transition section 22 is an acute angle or a right angle, such as 30°, 45°, 60°, 90°, etc. This angle parameter directly affects the deformation compensation capability and stress distribution characteristics of the busbar 2 in the thickness direction. A smaller angle has a larger extension stroke and better flexibility.

[0062] When the thickness of cell 1 expands, causing the spacing between tabs 12 to increase, the angle between connecting section 21 and transition section 22 increases. This angle change absorbs tensile strain, and the relatively small initial angle provides sufficient margin for angle change. When the thickness of cell 1 contracts, causing the spacing between tabs 12 to decrease, the angle returns to its initial state from the increased state. This angle decrease adapts to compressive strain and avoids excessive compressive stress.

[0063] In some embodiments, by limiting the angle between the connecting section 21 and the transition section 22 to no more than 90°, the deformation characteristics of the busbar 2 are optimized, so that the busbar 2 has a larger deformation stroke in the thickness direction of the cell 1, which can more effectively adapt to the changes in the spacing of the tabs 12 caused by the "breathing effect", while preventing stress concentration caused by excessive angle, thereby improving the fatigue resistance of the busbar 2 and the cycle life of the battery module.

[0064] In some embodiments, the busbar 2 includes a metal strip.

[0065] Understandably, metal strip is a strip-shaped product made from nickel, copper, aluminum, or their composite materials through a rolling process. As a basic industrial raw material, metal strip has good versatility and availability, and does not require special customization for specific battery models. Metal strip can be processed into the required corrugated structure using general stamping and bending equipment, and its specifications can be flexibly selected according to the needs of different battery modules.

[0066] When battery module design changes or model expansion occurs, the number of bends and spacing of the metal strip can be adjusted to accommodate different numbers of cells 1 connected in parallel, without needing to redesign the basic shape and connection method of the busbar 2. When applied to cells 1 of different sizes, only the width and bending angle of the metal strip need to be adjusted proportionally, maintaining the consistency of the basic structure.

[0067] In some embodiments, by using metal strips as the base material for busbar 2, the design of battery modules is made universal, allowing metal strips of the same specification to be adapted to various battery modules through different bending schemes, reducing the types of parts and mold investment; at the same time, standardized material selection simplifies supply chain management, improves production efficiency, facilitates rapid changeover and large-scale production of battery production lines, and effectively reduces overall manufacturing costs.

[0068] In some embodiments, the busbar 2 includes a nickel strip, a copper strip, or a copper-plated nickel strip.

[0069] It is understandable that nickel strip refers to strip made of pure nickel or nickel-based alloys, which has good weldability and corrosion resistance; copper strip refers to strip made of pure copper or copper alloys, which has excellent electrical and thermal conductivity; copper-plated nickel strip refers to composite strip with a nickel layer electroplated onto the surface of copper strip, which combines the high conductivity of the copper substrate with the good weldability and corrosion resistance of the nickel surface; these metal strips can be selected in appropriate specifications according to the current carrying capacity requirements.

[0070] In some embodiments, nickel strip, copper strip, or nickel-plated copper strip can be flexibly selected as the material for bus 2 according to electrical performance and process requirements. Nickel strip can ensure welding quality and environmental adaptability, and is suitable for applications with high corrosion resistance requirements; copper strip has low resistance in its conductive circuit, and is suitable for high-rate charging and discharging; nickel-plated copper strip has good conductivity and can ensure the welding stability between copper and aluminum tabs 12.

[0071] Reference Figure 8 and Figure 9 In some embodiments, the busbar 2 is welded to the tab 12.

[0072] It is understood that welding connection refers to the process of joining the busbar 2 and the tab 12 through melting or solid-state bonding. Welding connection methods include solid-state welding or fusion welding processes such as ultrasonic welding, laser welding, and resistance welding. Ultrasonic welding uses high-frequency vibration to induce plastic deformation at the contact surface to achieve connection; laser welding uses a high-energy-density beam to locally melt the material to form weld spots; resistance welding relies on the heat generated by the current passing through the contact resistance to complete the connection. The welding area can form continuous weld lines, discrete weld spots, or composite weld spot morphologies.

[0073] During welding, welding energy is applied to the interface between the busbar 2 and the tab 12, causing the interface material to undergo plastic flow or local melting, forming a dense metallic bond under pressure. After welding, the connecting section 21 and the tab 12 are mechanically fixed and electrically connected through the welding interface. The microstructure of the welding area forms a metallurgical bond with the base material, ensuring the stability and current-carrying capacity of the connection.

[0074] When assembling the battery module, the second part 122 of the tab 12 is first bent, and then the second part 122 of the tab 12 of one cell 1 is welded and fixed to the connecting section 21 of the busbar 2 by ultrasonic welding. Then, the insulating part 3 is bonded to the aluminum-plastic film sealing edge of the cell body 11. Next, the transition section 22 of the busbar 2 is bent for the first time, and then the connecting section 21 is welded to the tab 12 of the next cell 1 by ultrasonic welding, and a "Z" shaped bend is performed to form an angle of no more than 90°. This process is repeated to complete the welding of all cells 1 and the bending of the busbar 2 in sequence, and finally a busbar 2 with a continuous corrugated structure is formed, and the cells 1 of the battery module are connected in parallel. Among them, soft nickel strip, soft copper strip or soft copper-plated nickel strip is preferably used as the base material of the busbar 2, and the insulating part 3 continues to protect the aluminum-plastic film from the wear of the solder joints and the scratches of the tab 12.

[0075] In some embodiments, the current collector 2 and the tab 12 are fixed by welding, forming a connection with excellent conductivity and mechanical strength. The contact resistance is low, the connection reliability is high, and it can withstand the thermal shock when a large current passes through and the mechanical stress caused by the breathing effect of the cell 1. At the same time, the welding process is highly efficient and easy to automate, making it suitable for the large-scale production of battery modules and effectively ensuring the electrical safety and long-term reliability of the battery module.

[0076] In some embodiments, the battery module further includes at least one lead wire connected to the bus 2.

[0077] Understandably, a lead wire refers to a conductor electrically connected to busbar 2 and used to transmit module current outwards. Its cross-sectional area is determined according to current carrying requirements and can be fixed to busbar 2 by welding, riveting, or bolting. This battery module can have single-point lead wire output or multi-point evenly distributed lead wire output. Single-point lead wire output refers to setting a single lead wire at a suitable location on busbar 2, which is suitable for scenarios with concentrated current paths and low heat generation. Multi-point evenly distributed lead wire output refers to setting two or more lead wires at intervals along the length of busbar 2, allowing current to be output in parallel through multiple paths, which is suitable for high-current, high-rate discharge scenarios.

[0078] Under low-rate discharge conditions, the current is transmitted through a single-point lead, at which point the busbar 2 mainly serves as an electrical connection and mechanical buffer, and its structure is relatively simple. Under high-rate discharge conditions, the current is output in parallel through multiple evenly distributed leads, which effectively reduces the current density and temperature rise of the busbar 2 body, while improving the uniformity of current distribution and mitigating local overheating.

[0079] In some embodiments, the flexible configuration of single-point or multi-point leads allows the battery module to adapt to different discharge rates. A single-point lead design simplifies the structure, reduces costs, and is suitable for cost-sensitive low-rate applications. A multi-point evenly distributed lead design reduces the current load on the busbar 2 through current shunting, improves heat dissipation, and ensures electrical safety and thermal stability during high-rate discharge, making the battery module suitable for various application scenarios.

[0080] Reference Figure 10 and Figure 11 In some embodiments, the battery module includes two busbars 2, one busbar 2 connected to the positive terminal of each cell 1, and the other busbar 2 connected to the negative terminal of each cell 1.

[0081] It is understood that the two busbars 2 refer to the positive busbar 2 and the negative busbar 2, respectively, which are spatially insulated from each other and arranged in parallel. The positive busbar 2 is electrically connected to the positive electrode tabs 12 of all the battery cells 1 through its various connecting sections 21; the negative busbar 2 is electrically connected to the negative electrode tabs 12 of all the battery cells 1 through its various connecting sections 21, thus realizing the parallel connection of all the battery cells 1. The two busbars 2 can be made of the same or different metal materials, and can be designed differently according to the differences in the positive and negative current characteristics.

[0082] When the battery module is working, all cells 1 achieve voltage balance through the positive and negative busbars 2, and the total output current is the sum of the currents of each cell 1. When the thickness of a cell 1 changes due to internal differences, its corresponding connection section 21 and transition section 22 can deform independently without affecting the connection status of other cells 1. During charging and discharging, the parallel structure naturally achieves automatic current sharing among the cells 1.

[0083] In some embodiments, by connecting the battery cells 1 of the battery module in parallel and combining them with the flexible busbar 2 structure, synergistic optimization of electrical and mechanical performance is achieved. Electrically, this solution utilizes the low impedance characteristics of the busbar 2 to achieve natural voltage equalization among the cells 1 and provides extremely low total circuit impedance, thereby improving the high-rate discharge capability of the battery module. Mechanically, the flexible connection allows each cell 1 to cope with the "breathing effect" relatively independently, avoiding module-level accumulated stress caused by the deformation of a single cell 1, and improving the reliability of the overall structure.

[0084] According to a second aspect of this application, a battery pack is provided, which includes the battery module described above. This battery pack possesses all the beneficial effects of the battery module described above, which will not be elaborated further here.

[0085] According to a third aspect of this application, a battery cluster is provided, which includes the aforementioned battery module or battery pack. This battery cluster possesses all the beneficial effects of the aforementioned battery module or battery pack, which will not be elaborated further herein.

[0086] According to a fourth aspect of this application, an energy storage device is provided, comprising the aforementioned battery module, battery pack, or battery cluster. This energy storage device possesses all the beneficial effects of the aforementioned battery module, battery pack, or battery cluster, which will not be elaborated further herein.

[0087] Energy storage devices can take various forms, including but not limited to the following: Containerized energy storage systems integrate multiple battery clusters and supporting equipment into a standard container, facilitating transportation and rapid deployment, and are the mainstream form of large-scale energy storage power stations.

[0088] Prefabricated cabin-type energy storage system: Battery clusters, temperature control systems, fire protection systems, etc. are integrated into a customized cabin in the factory. Only basic treatment and wiring are required on site. It is suitable for grid-side and generation-side applications of various scales.

[0089] Cabinet-type energy storage system: It adopts a standardized cabinet design, with flexible capacity configuration, and is suitable for user-side scenarios with limited space, such as industrial and commercial parks and data centers.

[0090] In addition, this energy storage device can also be applied to other energy storage application scenarios that have high requirements for battery system safety, cycle life and rate performance.

[0091] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0092] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0093] The embodiments, implementation methods, and related technical features of this application can be combined and substituted for each other without conflict.

[0094] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. A battery module, characterized in that, include: Multiple battery cells (1) are arranged sequentially along their thickness direction. Each battery cell (1) includes a battery cell body (11) and a tab (12) that are electrically connected. The busbar (2) includes alternating connecting sections (21) and transition sections (22), each connecting section (21) being connected to each of the tabs (12), and adjacent connecting sections (21) and transition sections (22) being arranged at an angle. When two adjacent cells (1) are charged and discharged and the distance between the two tabs (12) changes, the transition section (22) can rotate relative to the connecting section (21).

2. The battery module according to claim 1, characterized in that, The tab (12) includes a first part (121) and a second part (122). The first part (121) is connected to the cell body (11). The second part (122) protrudes from the cell body (11) and bends toward one side of the thickness direction of the cell body (11). The connecting segment (21) is connected to the second part (122). When two adjacent cells (1) are charged and discharged and the distance between the two tabs (12) changes, the second part (122) can rotate toward the other side of the thickness direction of the cell body (11).

3. The battery module according to claim 2, characterized in that, The connecting segment (21) and the transition segment (22) have a circular arc transition; and / or, There is a circular arc transition between the first part (121) and the second part (122).

4. The battery module according to claim 2, characterized in that, The battery module also includes an insulating component (3), which is disposed between the second part (122) and the cell body (11).

5. The battery module according to claim 4, characterized in that, The insulating component (3) and the battery cell body (11) are bonded together.

6. The battery module according to any one of claims 1-5, characterized in that, The included angle between the connecting segment (21) and the transition segment (22) is no greater than 90°.

7. The battery module according to any one of claims 1-5, characterized in that, The busbar (2) includes a metal strip.

8. A battery pack, characterized in that, The battery module includes any one of claims 1-7.

9. A battery cluster, characterized in that, Includes the battery module according to any one of claims 1-7 or the battery pack according to claim 8.

10. An energy storage device, characterized in that, Includes the battery module according to any one of claims 1-7, the battery pack according to claim 8, or the battery cluster according to claim 9.

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