Battery cell, battery device, and electric device

Abstract

The present application relates to a battery cell, a battery device, and an electric device. The battery cell (10) comprises a casing assembly (11), an electrode assembly (12), and a current collecting assembly (13); the casing assembly (11) is provided with an accommodating cavity; the electrode assembly (12) is accommodated in the accommodating cavity; the electrode assembly (12) comprises a main body portion (121) and tabs (122), and the tabs (122) are arranged on at least one side of the main body portion (121) in a first direction (X); the current collecting assembly (13) is arranged between the casing assembly (11) and the main body portion (121) in the first direction (X); the current collecting assembly (13) comprises a first connecting member (131), the first connecting member (131) is connected to at least part of each tab (122), and the first connecting member (131) comprises a connecting portion (1311) and a stress dispersion portion (1312); the connecting portion (1311) is connected to the electrode assembly (12); in the first direction (X), the stress dispersion portion (1312) is connected to the surface of the connecting portion (1311) facing away from the electrode assembly (12), and a height difference is formed between the stress dispersion portion (1312) and the connecting portion (1311). In the battery cell (10) provided in the embodiments of the present application, the current collecting assembly (13) is provided with the connecting portion (1311) and the stress dispersion portion (1312) that have the height difference, thereby reducing stress transferred from the connecting portion (1311) to the stress dispersion portion (1312), and reducing the degree of deformation of the stress dispersion portion (1312).

Description

Battery cells, battery packs and electrical devices Cross-referencing

[0001] This application incorporates Chinese Patent Application No. 202520148108.9, filed on January 22, 2025, entitled “Battery Cell, Battery Device and Power Consumption Device”, which is incorporated herein by reference in its entirety. Technical Field

[0002] This application relates to the field of battery technology, and in particular to a battery cell, a battery device, and an electrical device. Background Technology

[0003] With the development of new energy technologies, batteries are being used more and more widely, for example in mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and power tools. Batteries are also widely used in the energy storage field.

[0004] With the widespread development and application of battery technology, how to improve the stability of the connection between various components during the assembly and use of battery cells, and improve the service life and safety performance of battery cells, is an urgent problem to be solved. Summary of the Invention

[0005] In view of the above problems, this application provides a battery cell, a battery, and an electrical device that can alleviate the problem of large gaps between the current collector and the end cap caused by deformation of the current collector due to local stress.

[0006] In a first aspect, this application provides a battery cell including a housing assembly, an electrode assembly, and a current collector assembly. The housing assembly has a receiving cavity; the electrode assembly is housed within the receiving cavity and includes a main body portion and tabs, the tabs being disposed on at least one side of the main body portion along a first direction; the current collector assembly is disposed between the housing assembly and the main body portion along the first direction, and includes a first connector, the first connector being connected to at least a portion of the tabs, the first connector including a connecting portion and a stress-dispersing portion; the connecting portion is connected to the electrode assembly, and in the first direction, the stress-dispersing portion is connected to the surface of the connecting portion facing away from the electrode assembly, and a height difference is formed between the stress-dispersing portion and the connecting portion.

[0007] In the technical solution of this application embodiment, instead of setting the surface of the current collector assembly facing the electrode assembly as a plane parallel to the end cap, providing a connecting portion and a stress-dispersing portion with a height difference in the current collector assembly allows some parts of the surface of the current collector assembly facing the electrode assembly to be stepped, thereby reducing the stress transmitted from the connecting portion to the stress-dispersing portion and reducing the degree of deformation of the stress-dispersing portion. That is, it reduces the deformation of the current collector assembly due to local stress, which increases the gap between the stress-dispersing portion and the end cap, thereby reducing the probability of poor welding quality.

[0008] In some embodiments, the stress-dispersing portion includes a middle portion and a shoulder portion. Along a first direction, the connecting portion is offset from the shoulder portion, the shoulder portion is connected to the housing assembly, and the middle portion is connected between the connecting portion and the shoulder portion.

[0009] Because the shoulder is connected to the middle section and the connecting section, and the shapes of the shoulder and the middle section are different from those of the connecting section, the stress can be diluted during the process of stress being transmitted from the connecting section to the shoulder. This reduces the stress transmitted to the shoulder, decreases the deformation of the shoulder under stress, and increases the probability of the gap between the shoulder and the housing assembly.

[0010] In some embodiments, the middle portion is configured to extend along the outer edge of the connector toward a first direction and away from the electrode assembly; the shoulder extends from the middle portion toward the housing assembly.

[0011] In this way, when the shoulder is connected to the end cap or the housing, the connection between the shoulder and the end cap or the housing is reduced, making welding easier.

[0012] In some embodiments, the housing assembly includes an end cap and a housing, with a receiving cavity formed within the housing. The end cap and a stress-dispersing portion are electrically connected, and the end cap is provided with a pressure relief mechanism.

[0013] With this configuration, when the internal pressure or temperature of a battery cell reaches a threshold, the internal pressure of the battery cell can be released through a pressure relief mechanism.

[0014] In some embodiments, the middle portion and the connecting portion together form a first groove, the first groove is recessed in the direction of the electrode assembly along the first direction, and in the same projection perpendicular to the first direction, the orthographic projection of the first groove completely covers the orthographic projection of the pressure relief mechanism.

[0015] With this configuration, the gas generated inside the housing assembly can flow through the first groove to the pressure relief mechanism and be discharged via the pressure relief mechanism. In addition, compared to a design without the first groove, this design can also reduce the weight of the current collection assembly itself.

[0016] In some embodiments, the connecting portion is provided with a through hole, and the through hole is disposed opposite to the pressure relief mechanism along the first direction.

[0017] Thus, because a through hole is provided on the connecting part, and this through hole is connected to the pressure relief mechanism on the housing assembly, the gas generated inside the housing assembly can be discharged through the through hole, the first groove, and the pressure relief mechanism when the battery cell is running. The first groove is designed to facilitate gas discharge. Compared to a solution without a through hole, this solution can also reduce the weight of the current collector assembly itself.

[0018] In some embodiments, the connection portion is connected to the tab of the electrode assembly via a first solder mark, and the connection portion completely covers the first solder mark.

[0019] This configuration can improve the current carrying capacity of the current collector.

[0020] In some embodiments, the diameter of the connecting part is d, where 33mm≤d≤38mm.

[0021] Considering the minimum current flow at the outermost ring of the electrode assembly and the minimum welding area that the current collector assembly can receive during external soldering, the dimensions of the connection are set accordingly. When the diameter of the connection is within the above-mentioned range, it can meet the usage requirements.

[0022] In some embodiments, along the first direction, the height of the middle part is L1, and the thickness of the connecting part itself is L2, where 0.5L2≤L1≤1L2.

[0023] By limiting the height range of the shoulder protrusion relative to the connecting part, the strength between the shoulder and the connecting part can meet the requirements.

[0024] In some embodiments, a second groove is formed between the stress-dispersing portion and the connecting portion. The second groove is located on the outer periphery of the connecting portion. The electrode includes a first electrode and a second electrode. The first electrode is connected to the connecting portion. The second electrode is disposed around the first electrode and connected to the first electrode. The second electrode is located in the second groove.

[0025] The electrode tabs are divided into a first tab and a second tab. The first tab connects to the electrode assembly and the second tab, while the second tab is located within a second recess and is not connected to the housing assembly. This tab configuration not only increases the capacity of the individual battery cells but also increases the internal space of the housing assembly, making it easier to assemble electrode assemblies of different shapes. Furthermore, it reduces the overcurrent temperature.

[0026] In some embodiments, the second groove is configured as an annular groove.

[0027] During the assembly of battery cells, because the second groove is an annular groove, the current collector assembly will not squeeze the tabs when assembled normally, reducing the probability of the tabs being compressed and damaged due to interference between the tabs and the current collector assembly.

[0028] In some embodiments, the connecting part and the base material of the electrode are the same, and the connecting part is connected to the electrode; the shoulder and the base material of the housing assembly are the same, and the shoulder is connected to the housing assembly; the base materials of the electrode and the housing assembly are different.

[0029] This design improves the connection strength between the connector and the tab, as well as between the shoulder and the housing assembly.

[0030] In some embodiments, the current collector assembly further includes a second connector, which is made of the same material as the housing assembly base and is connected to the housing assembly. The first connector is made of the same material as the tab base and is connected to the tab. The tab and the housing assembly base are made of different materials.

[0031] Thus, the additional second connector enhances the strength of the shoulder area, i.e. the connection strength between the entire current collector assembly and the housing assembly, reduces the probability of gaps between the current collector assembly and the end cap, and improves the welding stability of the current collector assembly.

[0032] In some embodiments, the shoulder is configured as an annular structure surrounding the periphery of the connector, and the second connector is configured as an annular structure layered on the shoulder facing the housing assembly along a first direction. In the same projection plane perpendicular to the first direction, the orthographic projection of the second connector at least partially overlaps with the orthographic projection on the shoulder.

[0033] Therefore, using different materials to prepare the shoulder and the second connector can improve the conductivity and mechanical strength of the current collector without affecting its existing performance, and reduce the production cost of the current collector.

[0034] In some embodiments, the connecting portion and the stress-dispersing portion are integrally formed.

[0035] This design simplifies the processing of the connecting parts and stress-dispersing parts, and improves the connection strength between them.

[0036] Secondly, this application provides a battery device that includes the battery cell described in the above embodiments.

[0037] Thirdly, this application provides an electrical device that includes the battery device described in the above embodiments.

[0038] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0039] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly described 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 the drawings without creative effort. In the drawings:

[0040] Figure 1 is a structural schematic diagram of a vehicle according to one or more embodiments.

[0041] Figure 2 is a schematic diagram of the structure of a battery cell according to one or more embodiments.

[0042] Figure 3 is an exploded view of a battery cell according to one or more embodiments.

[0043] Figure 4 is a cross-sectional view of a battery cell according to one or more embodiments.

[0044] Figure 5 is an enlarged view of point A in Figure 4.

[0045] Figure 6 is a schematic diagram of the current collector assembly of a battery cell according to one or more embodiments.

[0046] Figure 7 is a side view of the current collector assembly of a battery cell according to one or more embodiments.

[0047] The reference numerals in the detailed embodiments are as follows:

[0048] 1000, vehicles;

[0049] 100. Battery assembly; 200. Controller; 300. Motor;

[0050] 10. Battery cell; 11. Housing assembly; 111. End cap; 112. Housing; 12. Electrode assembly; 121. Main body; 122. Tab; 13. Current collector assembly; 131. First connector; 1311. Connecting part; 1312. Stress dispersion part; 13121. Middle part; 13122. Shoulder; 132. Second connector; 14. First groove; 15. Second groove; X, first direction; Y, second direction. Detailed Implementation

[0051] 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 some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0053] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0054] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0055] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0056] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0057] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0058] With the widespread use of batteries, battery safety has become increasingly important. Thermal runaway testing is one such test. Battery thermal runaway refers to the cumulative increase in current and battery temperature during constant-voltage charging, leading to gradual damage. Abnormal conditions may occur during battery use, such as overheating, overcharging, or external impacts. These abnormal conditions can trigger thermal runaway, leading to serious safety accidents, even fires and explosions. Thermal runaway testing aims to evaluate the safety performance of batteries under abnormal conditions, providing a scientific basis for battery design, production, and use, and reducing potential safety hazards.

[0059] Currently, judging from market trends, the application of power batteries is becoming increasingly widespread. Power batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also extensively used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. With the continuous expansion of power battery applications, market demand is also constantly increasing.

[0060] The current collector is a crucial component of a battery cell. In the battery cell assembly process, the electrode assembly is inserted into the housing assembly and the current collector is welded together, followed by welding the current collector and housing assembly together. The inventors discovered that during battery cell assembly, an interference fit is used in the thickness direction of the current collector to connect the housing assembly and the current collector. Specifically, along the thickness direction of the current collector, the housing assembly presses against the current collector, which in turn presses against the electrode tabs. To facilitate the smooth escape of gas from the electrode assembly, the housing assembly is equipped with venting components such as explosion-proof valves. Furthermore, a gap is created between the housing assembly and the current collector, meaning that the side of the current collector away from the electrode assembly lacks support and is in a state of stress imbalance. Under these conditions, the current collector can bend and deform. This bending and deformation results in a large gap between the current collector and the housing assembly, making the current collector prone to issues such as incomplete soldering and burn-through.

[0061] Based on the above considerations, in order to improve the problem of large gaps between the current collector assembly and the end cap caused by uneven deformation due to local stress, this application provides a battery cell including a housing assembly, an electrode assembly, and a current collector assembly. The current collector assembly is located between the main bodies of the housing assembly and the electrode assembly. The current collector assembly includes a connecting part and a stress-dispersing part connected together. The connecting part is connected to the electrode assembly, and the stress-dispersing part is connected to the surface of the connecting part facing away from the electrode assembly. Because a height difference is formed between the connecting part and the stress-dispersing part, when the connecting part is subjected to stress, the stress changes direction and decreases during the transmission to the stress-dispersing part. This reduces the likelihood of the stress-dispersing part moving away from the housing assembly due to stress, thus increasing the gap between the stress-dispersing part and the housing assembly and reducing the probability of deformation of the current collector assembly.

[0062] The battery cells disclosed in this application can be used, but are not limited to, in electrical devices such as vehicles, ships, or aircraft. A power system for such an electrical device can be constructed using battery cells and batteries disclosed in this application.

[0063] This application provides an electrical device that uses a battery as a power source. The electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, energy storage products, etc. 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, and energy storage products can include energy storage stations, etc.

[0064] For ease of explanation, the following embodiments will be described using a vehicle 1000 as an example of an electrical device according to an embodiment of this application.

[0065] Please refer to Figure 1, which is a structural schematic diagram of a vehicle 1000 provided in some embodiments of this application. The vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery device 100 is installed inside the vehicle 1000, and the battery device 100 can be located at the bottom, front, or rear of the vehicle 1000. The battery device 100 can be used to power the vehicle 1000; for example, the battery device 100 can serve as the operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery device 100 to supply power to the motor 300, for example, to meet the power needs of the vehicle 1000 during startup, navigation, and driving.

[0066] In some embodiments of this application, the battery device 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0067] The battery device 100 includes a housing and a battery cell 10, with the battery cell 10 housed within the housing. The housing provides a space for the battery cell 10 and can have various structures. In some embodiments, the housing may include a first portion and a second portion, which overlap each other, together defining a space for accommodating the battery cell 10. The second portion may be a hollow structure open at one end, while the first portion may be a plate-like structure, with the first portion covering the open side of the second portion so that the first and second portions together define the space. Alternatively, both the first and second portions may be hollow structures open on one side, with the open side of the first portion covering the open side of the second portion. Of course, the housing formed by the first and second portions can have various shapes, such as a cylinder, a cuboid, etc.

[0068] In the battery device 100, there can be multiple battery cells 10, which can be connected in series, parallel, or in a mixed manner. A mixed connection means that multiple battery cells 10 are connected in both series and parallel configurations. Multiple battery cells 10 can be directly connected in series, parallel, or in a mixed manner, and then the entire assembly of the multiple battery cells 10 is housed within a casing. Alternatively, the battery device 100 can also consist of multiple battery cells 10 first connected in series, parallel, or in a mixed manner to form battery modules, and then these battery modules are connected in series, parallel, or in a mixed manner to form a whole, which is then housed within a casing. The battery device 100 may also include other structures; for example, the battery may include a busbar component for electrical connection between the multiple battery cells 10.

[0069] Each battery cell 10 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited to these. The battery cell 10 can be cylindrical, flat, cuboid, or other shapes.

[0070] Referring to Figure 2, the battery cell 10 refers to the smallest unit that makes up the battery. As shown in Figures 2 and 3, the battery cell 10 includes a housing assembly 11, an electrode assembly 12, and other functional components.

[0071] The housing assembly 11 is a component that forms the internal environment of the battery cell 10, wherein the formed internal environment can accommodate the electrode assembly 12, the electrolyte, and other components. The housing assembly 11 can have various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing assembly 11 can be determined according to the specific shape and size of the electrode assembly 12. The material of the housing assembly 11 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not impose any special limitations on this.

[0072] Electrode assembly 12 is the component in the battery cell 10 where electrochemical reactions occur. The housing assembly 11 may contain one or more electrode assemblies 12. Electrode assembly 12 is mainly formed by winding or stacking positive and negative electrode sheets, and typically a separator is provided between the positive and negative electrode sheets. The portions of the positive and negative electrode sheets containing active material constitute the main body 121 of the electrode assembly 12, while the portions of the positive and negative electrode sheets without active material each constitute a tab 122. The positive and negative tabs 122 may be located together at one end of the main body 121 or separately at both ends of the main body 121. During the charging and discharging process of the battery, the positive and negative active materials react with the electrolyte, and the tabs 122 connect to the electrode terminals to form a current loop.

[0073] The following explanation uses a cylindrical battery cell, 10, as an example.

[0074] As shown in Figure 3, some embodiments of this application provide a battery cell 10, which includes a housing assembly 11, an electrode assembly 12, and a current collector assembly 13. The housing assembly 11 has a receiving cavity.

[0075] The electrode assembly 12 is housed inside the receiving cavity. The electrode assembly 12 includes a main body 121 and a tab 122. The tab 122 is disposed on at least one side of the main body 121 along the first direction X.

[0076] The current collector 13 is disposed between the housing assembly 11 and the main body 121 along the first direction X. The current collector 13 includes a first connector 131, which is connected to at least a portion of the tabs 122. The first connector 131 includes a connecting portion 1311 and a stress-dispersing portion 1312. The connecting portion 1311 is connected to the electrode assembly 12. In the first direction X, the stress-dispersing portion 1312 is connected to the surface of the connecting portion 1311 facing away from the electrode assembly 12. A height difference is formed between the stress-dispersing portion 1312 and the connecting portion 1311.

[0077] The housing assembly 11 has a cylindrical structure, which can be made of aluminum or steel and can be formed by stamping. Since the battery cell 10 is a cylindrical battery, the outer contour of the housing assembly 11 is also cylindrical. At least one end of the housing assembly 11 is open, and during assembly, the electrode assembly 12 can be inserted through the opening at one end of the housing assembly 11, and then the opening of the housing assembly 11 is sealed by the end cap 111 and / or the bottom cap.

[0078] The current collector 13 plays a crucial role in connecting multiple devices and transmitting signals in electronic components. The connecting portion 1311 and the stress-dispersing portion 1312 are made of the same material. The shape of the connecting portion 1311 can be, but is not limited to, rectangular or circular. The stress-dispersing portion 1312 is arranged around the outer periphery of the connecting portion 1311, and the connection between the stress-dispersing portion 1312 and the connecting portion 1311 can be stepped due to the height difference between them.

[0079] After the current collector 13 is placed inside the housing assembly 11, the stress dispersion portion 1312 is positioned further away from the electrode assembly 12 relative to the connecting portion 1311. That is, the distance between the stress dispersion portion 1312 and a certain part of the electrode assembly 12 is greater than the distance between the connecting portion 1311 and that part. The connecting portion 1311 is welded to the electrode assembly 12. During assembly, the connecting portion 1311 can be subjected to stress along the first direction X towards the outside of the housing assembly 11. Because the connection between the connecting portion 1311 and the stress dispersion portion 1312 is stepped, when stress is transmitted to the step, the stress can be reduced and its direction changed. This reduces the degree of deformation of the stress dispersion portion 1312, lowers the probability that the stress dispersion portion 1312 will move away from the housing assembly 11 under stress, and minimizes the increase in the gap between the stress dispersion portion 1312 and the housing assembly 11.

[0080] In summary, compared to setting the surface of the current collector 13 facing the electrode assembly 12 as a plane parallel to the housing assembly 11, providing a connecting portion 1311 and a stress-dispersing portion 1312 with a height difference in the current collector 13 allows some portions of the surface of the current collector 13 facing the electrode assembly 12 to be stepped, thereby reducing the stress transmitted from the connecting portion 1311 to the stress-dispersing portion 1312 and reducing the degree of deformation of the stress-dispersing portion 1312. This reduces the deformation of the current collector 13 due to localized stress, thus increasing the gap between the stress-dispersing portion 1312 and the housing assembly 11, and consequently reducing the probability of poor welding quality.

[0081] As shown in FIG4, in some embodiments, the stress dispersion portion 1312 includes a middle portion 13121 and a shoulder portion 13122. Along the first direction X, the connecting portion 1311 and the shoulder portion 13122 are offset. The shoulder portion 13122 is connected to the housing assembly 11, and the middle portion 13121 is connected between the connecting portion 1311 and the shoulder portion 13122.

[0082] For example, the middle portion 13121 can be constructed as an elongated strip. Of course, the shapes of the middle portion 13121 and the shoulder portion 13122 can also be similar, for example, both can be constructed as a ring structure. As long as the connecting portion 1311 and the shoulder portion 13122 are spaced apart from the middle portion 13121 in the first direction X, thus having a certain distance. The shoulder portion 13122 can be connected to the housing assembly 11.

[0083] Because the shoulder 13122 is connected to the connecting portion 1311 via the middle portion 13121, and the shapes of the shoulder 13122 and the middle portion 13121 are different from those of the connecting portion 1311, the stress can be diluted during the process of stress being transmitted from the connecting portion 1311 to the shoulder 13122, thereby reducing the stress transmitted to the shoulder 13122, reducing the probability of the shoulder 13122 deforming under stress, and increasing the gap between it and the housing assembly 11.

[0084] In some embodiments, the middle portion 13121 is configured to extend along the outer edge of the connecting portion 1311 in a first direction X and away from the electrode assembly 12, and the shoulder portion 13122 extends from the middle portion 13121 toward the housing assembly 11.

[0085] For example, the direction perpendicular to the wall thickness of the housing 112 is the second direction Y, which is perpendicular to the first direction X. Both the middle portion 13121 and the shoulder portion 13122 can be constructed as annular structures, but the middle portion 13121 extends along the first direction X, and the shoulder portion 13122 extends along the second direction Y.

[0086] When the shoulder 13122 is connected to the housing assembly 11, the connection between the shoulder 13122 and the housing assembly 11 is simplified, making welding easier.

[0087] Further, as shown in FIG4, in some embodiments, the housing assembly 11 includes an end cap 111 and a housing 112, wherein a receiving cavity is formed within the housing 112. The end cap 111 is electrically connected to the stress dispersion portion 1312, and a pressure relief mechanism is provided on the end cap 111.

[0088] End cap 111 refers to a component that covers the opening of housing 112 to isolate the internal environment of the receiving cavity from the external environment. The shape of end cap 111 can be adapted to the shape of the opening of housing 112 to fit housing 112. Alternatively, end cap 111 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that end cap 111 is not easily deformed under compression and impact, giving the housing assembly 11 higher structural strength and improved safety performance. The material of end cap 111 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. Functional components such as electrode terminals can be provided on end cap 111. Electrode terminals can be used for electrical connection with electrode assembly 12 to output or input electrical energy to battery cell 10.

[0089] With this configuration, when the internal pressure or temperature of the battery cell 10 reaches a threshold, the internal pressure of the battery cell 10 can be released through the pressure relief mechanism.

[0090] In some embodiments, the middle portion 13121 and the connecting portion 1311 together form a first groove 14. The first groove 14 is recessed in the direction of the electrode assembly 12 along the first direction X. In the same projection perpendicular to the first direction X, the orthographic projection of the first groove 14 completely covers the orthographic projection of the pressure relief mechanism.

[0091] When the current collector 13 is assembled inside the housing assembly 11, a gap exists between the connecting portion 1311 and the end cap 111 of the housing assembly 11 because the middle portion 13121 and the connecting portion 1311 together form a first groove 14 that is recessed towards the electrode assembly 12. In addition, the orthographic projection of the first groove 14 covers the pressure relief mechanism, so the gas generated inside the housing assembly 11 can flow through the first groove 14 to the pressure relief mechanism and be discharged through the pressure relief mechanism.

[0092] In addition, compared to the solution without the first groove 14, this solution can also reduce the weight of the current collection component 13 itself.

[0093] In some embodiments, the connecting portion 1311 is provided with a through hole, and the through hole is disposed opposite to the pressure relief mechanism along the first direction X.

[0094] For example, the through hole on the connecting part 1311 can be used not only as a weight-reducing hole, but also as a clamp to hold the connecting part 1311. When the through hole is made, it should avoid the welding area to reduce the impact on the welding.

[0095] Because the connecting part 1311 has a through hole, which is connected to the pressure relief mechanism on the housing assembly 11, when the battery cell 10 is running, the gas generated inside the housing assembly 11 can be discharged through the through hole, the first groove 14, and the pressure relief mechanism, wherein the first groove 14 is provided to facilitate the discharge of gas. Compared with the solution without a through hole, this solution can also reduce the weight of the current collector assembly 13 itself.

[0096] In some embodiments, the connection portion 1311 is connected to the tab 122 of the electrode assembly 12 via a first solder mark, and the connection portion 1311 completely covers the first solder mark.

[0097] This configuration can improve the current carrying capacity of the current collection component 13.

[0098] Further, as shown in Figures 6 and 7, in some embodiments, the diameter of the connecting portion 1311 is d, where 33 mm ≤ d ≤ 38 mm. The bottom wall of the first groove 14 can be approximately circular. d is the diameter of its bottom wall, and the specific value of d can be mm, 4 mm, 6 mm, 8 mm, or any value between two adjacent values.

[0099] Considering the minimum current flow at the outermost ring of the electrode assembly 12 and the minimum welding area that the current collector assembly 13 can withstand during external welding, the dimensions of the connection portion 1311 are set accordingly. When the diameter of the connection portion 1311 is within the above-mentioned range, it can meet the usage requirements.

[0100] In some embodiments, as shown in FIG5, along the first direction X, the height of the middle part 13121 is L1, and the thickness of the connecting part 1311 itself is L, where 0.5L≤L1≤1L.

[0101] When L1 equals 0.5L, the strength between the shoulder 13122 and the connecting portion 1311 is better. The thickness of the shoulder 13122, the middle portion 13121 and the connecting portion 1311 are equal, so that the shoulder 13122, the middle portion 13121 and the connecting portion 1311 can be machined on the first connecting member 131.

[0102] By limiting the height range of the middle part 13121, the strength between the shoulder part 13122 and the connecting part 1311 can meet the requirements.

[0103] Please refer to Figures 4 and 7. In some embodiments, a second groove 15 is formed between the stress dispersion portion 1312 and the connecting portion 1311. The second groove 15 is located on the outer periphery of the connecting portion 1311. The electrode tab 122 includes a first electrode tab and a second electrode tab. One end of the first electrode tab is connected to the connecting portion 1311. The second electrode tab is arranged around the first electrode tab and is connected to the first electrode tab. The second electrode tab is located in the second groove 15.

[0104] The tab 122 is divided into a first tab and a second tab. The first tab is used to connect the electrode assembly 12 and the second tab, while the second tab is located within the second groove 15 and is not connected to the housing assembly 11. This arrangement of the tab 122 not only increases the capacity of the individual battery cell but also increases the internal space of the housing assembly 11, making it easier to assemble electrode assemblies 12 of different shapes. Furthermore, it reduces the overcurrent temperature.

[0105] Of course, in other embodiments, the second tab may not be located within the second groove 15, in which case the energy density of the battery cell 10 is higher.

[0106] Specifically, in some embodiments, the second groove 15 is configured as an annular groove.

[0107] During the assembly of the battery cell 10, because the second groove 15 is an annular groove, the current collector 13 will not squeeze the tab 122 when it is assembled normally, which reduces the probability that the tab 122 will be damaged due to interference between the tab 122 and the current collector 13.

[0108] The current collector assembly 13 includes a single-layer current collector and a double-layer current collector. The double-layer current collector, through its unique "sandwich" structure, utilizes the multiple coupling relationships of the mechanical, electrical, and thermal properties between the metal layer and the polymer layer, overcoming the functional limitations of the single-layer current collector. During use, this structure is less prone to breakage, helping to reduce the risk of micro-short circuits and thus improving the battery's safety performance.

[0109] In some embodiments, the housing assembly 11 can be made of steel, and the connection end between the electrode assembly 12 and the current collector assembly 13 is a negative electrode tab, which can be made of copper. Since the melting point of copper is about 1080°C and the melting point of steel is about 1400°C, direct laser welding of the two can easily produce small cracks, which cannot meet the airtightness requirements. Therefore, the current collector assembly 13 needs to be designed as a composite structure. The connection part 1311 connected to the electrode tab 122 can be made of the same material as the base material of the electrode tab 122, and the shoulder part 13122 connected to the housing assembly 11 can be made of the same material as the base material of the housing assembly 11.

[0110] In some embodiments, the connecting portion 1311 and the tab 122 are made of the same base material, the connecting portion 1311 is connected to the tab 122, the shoulder portion 13122 and the housing assembly 11 are made of the same base material, the shoulder portion 13122 is connected to the housing assembly 11, and the tab 122 and the housing assembly 11 are made of different base materials.

[0111] For example, the connecting portion 1311 can be connected to the first electrode tab 122, and both the connecting portion 1311 and the first electrode tab 122 can be made of aluminum. The shoulder portion 13122 and the housing assembly 11 can both be made of copper, and the material used for the intermediate portion 13121 can be the same as that used for the connecting portion 1311 or the shoulder portion 13122. This arrangement improves the connection strength between the connecting portion 1311 and the electrode tab 122, and between the shoulder portion 13122 and the housing assembly 11.

[0112] As shown in Figure 4, in some embodiments, the current collector 13 further includes a second connector 132, which is made of the same material as the base material of the housing assembly 11 and is connected to the housing assembly 11. The first connector 131 is made of the same material as the base material of the tab 122 and is connected to the tab 122. The tab 122 is made of a different material than the base material of the housing assembly 11.

[0113] For example, the first connector 131 may be made of aluminum, and both the second connector 132 and the housing assembly 11 may be made of copper. The shape of the second connector 132 may be the same as that of the shoulder 13122, and it may only be provided on the shoulder 13122.

[0114] Assume the second connector 132 is constructed as a ring, with one end welded to the end cap 111 and the other end welded to the shoulder 13122. Because the second connecting portion 1311 is not connected to the connecting portion 1311, the thickness of the area where the shoulder 13122 is located is increased. Since the second connector 132 is also connected to the end cap 111, the stress transmitted to the shoulder 13122 needs to be sufficiently large to cause the shoulder 13122 and the second connector 132 to deform together.

[0115] Thus, by providing an additional second connector 132, the strength of the part where the shoulder 13122 is located is enhanced, that is, the connection strength between the entire current collector assembly 13 and the housing assembly 11 is increased, the probability of gaps appearing between the current collector assembly 13 and the end cap 111 is reduced, and the welding stability of the current collector assembly 13 is improved.

[0116] Specifically, as shown in FIG6, in some embodiments, the shoulder 13122 is configured as an annular structure surrounding the outer periphery of the connecting portion 1311, and the second connecting member 132 is an annular structure layered on the shoulder 13122 facing the housing assembly 11 along the first direction X. In the same projection plane perpendicular to the first direction X, the orthographic projection of the second connecting member 132 at least partially overlaps with the orthographic projection on the shoulder 13122.

[0117] The shoulder 13122 can be made of materials such as copper or aluminum, while the second connector 132 can be made of steel. Steel has properties such as high strength, low weight, uniform material, and good plasticity. Copper itself has good electrical conductivity and is often used in applications involving current transmission. Moreover, copper is inexpensive and readily available.

[0118] Using different materials to prepare the shoulder 13122 and the second connector 132 can improve the conductivity and mechanical strength of the current collector 13 without affecting its existing performance, and reduce the production cost of the current collector 13.

[0119] In some embodiments, the connecting portion 1311 and the stress dispersing portion 1312 are integrally formed.

[0120] This design simplifies the processing of the connecting part 1311 and the stress-dispersing part 1312, and improves the connection strength between the connecting part 1311 and the stress-dispersing part 1312.

[0121] Some embodiments of this application also provide a battery device 100, which includes the battery cell 10 in the above embodiments. Therefore, the battery device 100 has the effects achieved by the battery cell 10.

[0122] Furthermore, some embodiments of this application also provide an electrical device that includes the battery device 100 described in the above embodiments. Therefore, the electrical device possesses the effects achieved by the battery device 100.

[0123] In one specific embodiment, the battery cell 10 includes a housing assembly 11, an electrode assembly 12, and a current collector assembly 13. The electrode assembly 12 is housed inside the housing assembly 11; the current collector assembly 13 is located between the housing assembly 11 and the electrode assembly 12. The first connector 131 includes a connecting portion 1311 and a stress-dispersing portion 1312. The stress-dispersing portion 1312 includes a middle portion 13121 and a shoulder portion 13122. The middle portion 13121 is connected to the connecting portion 1311 and protrudes along its outer edge in a direction away from the electrode assembly 12. The shoulder portion 13122 is annular and is connected to the end of the middle portion 13121 away from the connecting portion 1311 and extends outward toward the housing assembly 11. Along the thickness direction of the end cap 111, the first connector 131 is recessed toward the electrode assembly 12 to form a first groove 14. A second groove 15 is formed between the stress-dispersing portion 1312 and the connecting portion 1311. The second groove 15 is located on the outer periphery of the connecting portion 1311. The electrode assembly 12 includes a tab 122, a portion of which is located in the second groove 15 and is in contact with the connecting portion 1311.

[0124] Instead of making the surface of the current collector 13 facing the electrode assembly 12 a plane parallel to the end cap 111, providing a connecting portion 1311 and a stress-dispersing portion 1312 with a height difference in the current collector 13 allows some portions of the surface of the current collector 13 facing the electrode assembly 12 to be stepped, thereby reducing the stress transmitted from the connecting portion 1311 to the stress-dispersing portion 1312 and reducing the degree of deformation of the stress-dispersing portion 1312. This reduces deformation of the current collector 13 due to localized stress, thus increasing the gap between the stress-dispersing portion 1312 and the end cap 111, and consequently reducing the probability of poor welding quality.

[0125] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0126] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A battery cell, wherein, include: The housing assembly has a receiving cavity; An electrode assembly is housed within the receiving cavity. The electrode assembly includes a main body and an electrode tab, the electrode tab being disposed on at least one side of the main body along a first direction. A current collector assembly is disposed between the housing assembly and the main body portion along the first direction, the current collector assembly including a first connector, the first connector being connected to at least a portion of the tabs; The first connector includes a connecting portion and a stress-dispersing portion. The connecting portion is connected to the electrode assembly. In the first direction, the stress-dispersing portion is connected to the surface of the connecting portion facing away from the electrode assembly. A height difference is formed between the stress-dispersing portion and the connecting portion. The stress-dispersing portion is electrically connected to the housing assembly.

2. The battery cell according to claim 1, wherein, The stress-dispersing portion includes a middle portion and a shoulder portion. Along the first direction, the connecting portion is offset from the shoulder portion. The shoulder portion is connected to the housing assembly, and the middle portion is connected between the connecting portion and the shoulder portion.

3. The battery cell according to claim 2, wherein, The middle portion is configured to extend along the outer edge of the connecting portion toward the first direction and away from the electrode assembly; the shoulder extends from the middle portion toward the housing assembly.

4. The battery cell of claim 2, wherein, The outer casing assembly includes an end cap and a housing, the end cap being electrically connected to the stress dispersion section, and the end cap being provided with a pressure relief mechanism.

5. The battery cell of claim 4, wherein, The middle portion and the connecting portion together form a first groove, which is recessed toward the electrode assembly along the first direction. In the same projection perpendicular to the first direction, the orthographic projection of the first groove completely covers the orthographic projection of the pressure relief mechanism.

6. The battery cell according to claim 4, wherein, The connecting part is provided with a through hole, and along the first direction, the through hole is arranged opposite to the pressure relief mechanism.

7. The battery cell according to claim 2, wherein, The connection portion is connected to the tab of the electrode assembly via a first solder mark, and the connection portion completely covers the first solder mark.

8. The battery cell of claim 7, wherein, The diameter of the connecting part is d, 33mm≤d≤38mm.

9. The battery cell according to claim 2, wherein, Along the first direction, the height of the middle part is L1, and the thickness of the connecting part itself is L2, where 0.5L2≤L1≤1L2.

10. The battery cell according to any one of claims 1 to 9, wherein, The stress-dispersing portion and the connecting portion together form a second groove, which is located on the outer periphery of the connecting portion. The electrode includes a first electrode and a second electrode. The first electrode is connected to the connecting portion, and the second electrode is arranged around the first electrode and connected to the first electrode. The second electrode is located in the second groove.

11. The battery cell according to claim 10, wherein, The second groove is constructed as an annular groove.

12. The battery cell according to any one of claims 2 to 9, wherein, The connecting part and the base material of the electrode are the same, and the connecting part is connected to the electrode. The shoulder and the base material of the outer shell assembly are the same, and the shoulder is connected to the outer shell assembly. The base material of the electrode and the base material of the outer shell assembly are different.

13. The battery cell according to any one of claims 2 to 9, wherein, The current collection assembly further includes a second connector, which is made of the same material as the base material of the housing assembly and is connected to the housing assembly. The first connector is made of the same material as the base material of the electrode and is connected to the electrode. The electrode and the base material of the housing assembly are different.

14. The battery cell according to claim 13, wherein, The shoulder is configured as an annular structure surrounding the outer periphery of the connecting portion, and the second connector is configured as an annular structure layered on the shoulder facing the housing assembly along the first direction. In the same projection plane perpendicular to the first direction, the orthographic projection of the second connector at least partially overlaps with the orthographic projection of the shoulder.

15. The battery cell according to any one of claims 1 to 9, wherein, The connecting part and the stress dispersing part are integrally formed.

16. A battery device, wherein, Includes the battery cell as described in any one of claims 1 to 15.

17. An electrical appliance, wherein, Includes the battery device as described in claim 16.

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