Battery monomer, battery device, power utilization device and preparation method of battery monomer

Abstract

The invention belongs to the technical field of battery production, and provides a single battery, a battery device, a power utilization device and a preparation method of the single battery, the single battery comprises a shell, a first electrode terminal, at least two electrode assemblies and at least two first adapters, the shell is provided with an accommodating cavity and a first end wall, and the first electrode terminal is arranged on the first end wall; the electrode assemblies are arranged in the accommodating cavity, and each electrode assembly comprises a first tab; the first adapters are matched with the first tabs in a one-to-one correspondence mode, and the first tabs of all the electrode assemblies are electrically connected with the first electrode terminals through the corresponding first adapters. The invention aims to improve the overcurrent capability of the battery monomer.

Description

Technical Field

[0001] This application relates to the field of battery manufacturing technology, and in particular to a battery cell, a battery device, an electrical device, and a method for preparing a battery cell. Background Technology

[0002] Lithium-ion batteries are widely used in new energy vehicles, energy storage devices, and other fields due to their high energy density and long cycle life. As application scenarios increase the power requirements of batteries, the overcurrent capacity of individual battery cells has become one of the key factors affecting battery performance.

[0003] In related technologies, the limitations of the connection between the electrode components and electrode terminals of a battery cell often lead to insufficient overcurrent capacity of the battery cell, which in turn affects the performance of the battery cell. Summary of the Invention

[0004] The purpose of this application is to provide a battery cell, a battery device, an electrical device, and a method for preparing a battery cell, aiming to solve the technical problem of insufficient overcurrent capacity of battery cells.

[0005] In a first aspect, this application provides a battery cell, comprising:

[0006] The outer casing has a receiving cavity and a first end wall; The first electrode terminal is disposed on the first end wall; At least two electrode assemblies are disposed within the accommodating cavity, and each electrode assembly includes a first electrode tab. At least two first adapters are provided, each corresponding to a first electrode tab. The first electrode tabs of each electrode assembly are electrically connected to the first electrode terminal through the corresponding first adapter.

[0007] In this embodiment, by replacing the traditional integrated adapter piece with a separate first adapter, a first adapter is welded to the first tab on one electrode assembly. This allows the connection between the first tab and the first adapter to be ultrasonically welded using a transverse welding process. Combined with increasing the length of the welding head, the welding length between the first tab and the first adapter can be increased, thereby increasing the welding area and improving the current carrying capacity between the first tab and the first adapter. In addition, compared with traditional longitudinal welding, the design of the separate first adapter reduces the mutual pulling problem caused by multiple electrode assemblies being connected through the same adapter, which is beneficial to improving the connection stability between the electrode assembly, the first adapter, and the first electrode terminal.

[0008] In one embodiment, along a first direction, a first electrode terminal is disposed toward the end of an electrode assembly having a first tab, and multiple electrode assemblies are stacked sequentially in a second direction, the second direction being perpendicular to the first direction; in the second direction, multiple first adapters are sequentially disposed, and any two adjacent first adapters are spaced apart in the second direction.

[0009] In this embodiment, any two adjacent first adapters are spaced apart in the second direction, which can reduce the risk of interference when assembling with the first electrode terminal, and also save the manufacturing materials of the adapters, improve the heat dissipation effect, and further improve the current carrying capacity.

[0010] In one embodiment, along a first direction, a first electrode terminal is disposed toward the end of an electrode assembly having a first tab, and multiple electrode assemblies are stacked sequentially in a second direction; in a third direction, a first adapter has a first length; the first tab is welded to the first adapter to form a first welding area, and the first welding area has a second length in a third direction, the second length being 50%-100% of the first length; the first direction, the second direction, and the third direction are perpendicular to each other.

[0011] In this embodiment, a first electrode tab is matched and connected to a first adapter, which enables the first electrode tab and the first adapter to be welded laterally and form a first welding area with a length exceeding 50% of the length of the first adapter, thereby increasing the effective welding area and improving the current carrying capacity between the first electrode tab and the first adapter.

[0012] In one embodiment, along a first direction, the first electrode terminal is disposed toward the end of the electrode assembly that has the first tab; along the first direction, the end of the first electrode terminal that faces each of the first tabs has a first groove structure corresponding to each of the first adapters, and the first adapter is at least partially accommodated in the first groove structure.

[0013] In this embodiment, by setting the first groove structure, the first adapter can be limited and positioned, which is conducive to improving space utilization and increasing the energy density of the battery cell.

[0014] In one embodiment, along a first direction, a first electrode terminal is disposed toward the end of an electrode assembly having a first tab, and multiple electrode assemblies are stacked sequentially in a second direction, the second direction being perpendicular to the first direction; each first tab is welded to each first adapter at a first position to form a first welding area, and the first electrode terminal is welded to each first adapter at a second position to form a second welding area; in the second direction, the extended portion of the first electrode terminal connected to the first adapter extends beyond the first position, such that the first welding area and the second welding area at least have an overlapping portion, or the extended portion of the first electrode terminal connected to the first adapter avoids the first position, such that the first welding area and the second welding area are spaced apart.

[0015] In this embodiment, the overlapping of the first welding area and the second welding area can improve the reliability of the connection. The method of setting the first welding area and the second welding area alternately is suitable for situations that are sensitive to high-temperature laser welding and can reduce mutual interference between different welding methods.

[0016] In one embodiment, along a first direction, the first electrode terminal is disposed toward the end of the electrode assembly with the first tab, and multiple electrode assemblies are stacked sequentially in a second direction, which is perpendicular to the first direction; the first electrode terminal is welded to each of the first adapters at a second position to form a second welding area, and the second welding area spans between any two adjacent first adapters.

[0017] In this embodiment, the second welding area spans between two adjacent first adapters to enhance the cooperative stability between adjacent first adapters, improve the uniformity of current flow, and ensure the working stability of the battery cell.

[0018] In one embodiment, there are two electrode assemblies. The first electrode terminal is disposed opposite to the electrode assembly in a first direction. In a second direction, the first electrode terminal has two protruding first outer edges, which are electrically connected to the two first adapters respectively. The first direction is perpendicular to the second direction.

[0019] In this embodiment, a configuration of two electrode assemblies is adopted, which allows the two electrode assemblies to be symmetrically arranged on both sides of the first electrode terminal. The connection between the first adapter and the first electrode terminal is also more reliable, which helps to improve the stability of the entire battery cell.

[0020] In one embodiment, the battery cell further includes a second electrode terminal and a second adapter. The second electrode terminal is disposed on the first end wall and is arranged at a distance from the first electrode terminal. Each electrode assembly also includes a second tab, and the second tab of each electrode assembly is electrically connected to the second electrode terminal through the second adapter.

[0021] In this embodiment, based on the split-type first adapter design, a split-type second adapter is further adopted between the second tab and the second electrode assembly. One second adapter is welded to the second tab on each electrode assembly, so that the connection position between the second tab and the second adapter can be ultrasonically welded using a transverse welding process. Combined with increasing the length of the welding head, the welding length between the second tab and the second adapter can be increased, thereby increasing the welding area and improving the current carrying capacity between the second tab and the second adapter. Compared with traditional longitudinal welding, the split-type second adapter design reduces the mutual pulling problem caused by multiple electrode assemblies being connected through the same adapter, which is beneficial to improving the connection stability between the electrode assembly, the second adapter, and the second electrode terminal.

[0022] In one embodiment, along the first direction, the second electrode terminal is disposed toward the end of the electrode assembly that has the second tab, and multiple electrode assemblies are stacked sequentially in the second direction, which is perpendicular to the first direction; in the second direction, multiple second adapters are disposed sequentially, and any two adjacent second adapters are arranged at intervals in the second direction.

[0023] In this embodiment, any two adjacent second adapters are spaced apart in the second direction, which can reduce the risk of interference when assembling with the second electrode terminal, and also save the manufacturing materials of the adapters, improve the heat dissipation effect, and further improve the current carrying capacity.

[0024] In one embodiment, along the first direction, the second electrode terminal is disposed toward the end of the electrode assembly with the second tab, and multiple electrode assemblies are stacked sequentially in the second direction; in the third direction, the second adapter has a third length; the second tab is welded to the second adapter to form a third welding area, and the third welding area has a fourth length in the third direction, the fourth length being 50%-100% of the third length; the first direction, the second direction, and the third direction are perpendicular to each other.

[0025] In this embodiment, a structure in which a second electrode tab is matched and connected to a second adapter allows the second electrode tab and the second adapter to be welded laterally, forming a third welding area with a length exceeding 50% of the length of the second adapter, thereby increasing the effective welding area and improving the current carrying capacity between the second electrode tab and the second adapter.

[0026] In one embodiment, along the first direction, the second electrode terminal is disposed toward the end of the electrode assembly that has the second tab, and along the first direction, the side of the second electrode terminal facing each of the second tabs has a second groove structure corresponding to each of the second adapters, and the second adapter is at least partially accommodated in the second groove structure.

[0027] In this embodiment, by setting the second groove structure, the second adapter can be limited and positioned, which is conducive to improving space utilization and increasing the energy density of the battery cell.

[0028] In one embodiment, along a first direction, the second electrode terminal is disposed toward the end of the electrode assembly with the second tab, and multiple electrode assemblies are stacked sequentially in a second direction, the second direction being perpendicular to the first direction; each second tab is welded to each second adapter at a third position to form a third welding area, and the second electrode terminal is welded to each second adapter at a fourth position to form a fourth welding area; in the second direction, the extended portion of the second electrode terminal connected to the second adapter extends beyond the third position, such that the third welding area and the fourth welding area have at least an overlapping portion, or the extended portion of the second electrode terminal connected to the second adapter avoids the third position, such that the third welding area and the fourth welding area are spaced apart.

[0029] In this embodiment, the overlapping of the third and fourth welding areas can improve the reliability of the connection. The method of setting the third and fourth welding areas alternately is suitable for situations that are sensitive to high-temperature laser welding, and can reduce mutual interference between different welding methods.

[0030] In one embodiment, along the first direction, the second electrode terminal is disposed toward the end of the electrode assembly that has the second tab, and multiple electrode assemblies are stacked sequentially in the second direction, which is perpendicular to the first direction; the second electrode terminal is welded to each of the second adapters at the fourth position to form a fourth welding area, and the fourth welding area spans between any two adjacent second adapters.

[0031] In this embodiment, the fourth welding area spans between two adjacent second adapters to enhance the cooperative stability between adjacent second adapters, improve the uniformity of current flow, and ensure the working stability of the battery cell.

[0032] In one embodiment, two electrode assemblies are provided. The second electrode terminal is disposed opposite to the electrode assembly in a first direction. In a second direction, the second electrode terminal is provided with two protruding second outer edges, which are electrically connected to the two second adapters respectively. The first direction is perpendicular to the second direction.

[0033] In this embodiment, a configuration of two electrode assemblies is adopted, which allows the two electrode assemblies to be symmetrically arranged on both sides of the second electrode terminal. The connection between the second adapter and the second electrode terminal is also more reliable, which helps to improve the stability of the entire battery cell.

[0034] In one embodiment, the multiple second adapters in the multiple electrode assemblies are an integral structure.

[0035] In this embodiment, multiple second adapters adopt an integrated structure, which can reduce the number of welding operations, improve welding efficiency, and form a reasonable combination with multiple separate first adapters, thereby increasing the diversity of battery cell structures and improving manufacturing flexibility.

[0036] Secondly, this application provides a battery device, which includes a battery cell as described in any of the above.

[0037] Thirdly, this application provides an electrical device, which includes a battery cell as described in any of the above claims or a battery device as described in any of the above claims, the battery device being used to store or provide electrical energy.

[0038] Fourthly, this application provides a method for preparing a battery cell, the method being used to prepare a battery cell as described in any of the above claims, the method comprising: The prefabricated housing, first electrode terminal, multiple electrode assemblies, and multiple first adapters, each electrode assembly having a first tab; Each first electrode tab is welded to each first adapter piece in a corresponding manner; Multiple first adapters are welded to the first electrode terminals to form an integral electrode assembly; The electrode assembly is assembled with the housing.

[0039] In this embodiment, the adapter adopts a split structure of multiple first adapters, allowing independent welding between each first electrode tab and each first adapter. This makes the welding method more flexible and enables the welding area between the first electrode tab and the first adapter to be increased through lateral welding, thereby improving the current carrying capacity between them. Furthermore, this fabrication method employs a "step-by-step welding combined with overall assembly" approach. The dispersed electrode components are first integrated into a single assembly via the first adapter and the first electrode terminal, and then the entire assembly is encapsulated. Compared to the traditional process of "encapsulating each electrode component individually and then welding," overall assembly reduces the number of encapsulation steps and internal welding operations, lessens the limitations imposed by the confined space within the housing on welding operations, significantly improves assembly efficiency, and is suitable for large-scale mass production.

[0040] In one embodiment, the first electrode tab and the first adapter are ultrasonically welded, and the ultrasonic welding method is transverse welding.

[0041] In this embodiment, the vibration direction of the transverse welding is parallel to the width direction (second direction) of the first adapter, which enables the welding energy to be evenly distributed on the welding surface, which helps to reduce the problem of energy concentration or dispersion. The transverse welding process can ensure that the welding area is fully extended, forming a sufficiently large welding area, improving the current carrying capacity, ensuring welding quality, reducing the risk of false welding, and improving the reliability of the first polarity conduction path.

[0042] In one embodiment, a second electrode terminal and a plurality of second adapters are prefabricated; each electrode assembly has a second tab, and while each first tab is welded to each first adapter in a one-to-one correspondence, each second tab is also welded to each second adapter in a one-to-one correspondence; while the plurality of first adapters are all welded to the first electrode terminal, the plurality of second adapters are also welded to the second electrode terminal to form an integral electrode assembly.

[0043] In this embodiment, because the adapter adopts a split structure of multiple second adapters, one second electrode tab and one second adapter can be welded independently, making the welding method more flexible. It can further increase the welding area between the second electrode tab and the second adapter through the transverse welding process, thereby improving the current carrying capacity between the second electrode tab and the second adapter. In addition, when welding the first electrode tab and the first adapter, the second electrode tab and the second adapter can be welded simultaneously on the welding equipment without the need for equipment such as a robot to change the work station, so as to complete the welding of the adapter and the electrode assembly, thereby improving the manufacturing efficiency.

[0044] In one embodiment, the second electrode tab and the second adapter are ultrasonically welded, and the ultrasonic welding method is transverse welding.

[0045] In this embodiment, the vibration direction of the transverse welding is parallel to the width direction (second direction) of the second adapter, which enables the welding energy to be evenly distributed on the welding surface, which helps to reduce the problem of energy concentration or dispersion. The transverse welding process can ensure that the welding area is fully extended, forming a sufficiently large welding area, improving the current carrying capacity, ensuring welding quality, reducing the risk of false welding, and improving the reliability of the first polarity conduction path.

[0046] 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

[0047] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0048] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments; Figure 2 This is an exploded view of the battery device provided in some embodiments of this application; Figure 3 Schematic diagram of the internal structure of a battery cell provided in some embodiments of this application Figure 1 ; Figure 4 This is a schematic diagram showing the connection between the electrode assembly, the first tab, the first adapter, the second tab, and the second adapter in a battery cell according to some embodiments of this application. Figure 5 Schematic diagram of the internal structure of a battery cell provided in some embodiments of this application Figure 2 ; Figure 6 This illustration shows the state of the electrode assembly, first tab, first adapter, second tab, and second adapter in a battery cell provided in some embodiments of this application during welding in a welding equipment. Figure 1 ; Figure 7 This illustration shows the state of the electrode assembly, first tab, first adapter, second tab, and second adapter in a battery cell provided in some embodiments of this application during welding in a welding equipment. Figure 2 ; Figure 8 This application provides schematic diagrams illustrating the structure of a battery cell after the connection of the electrode assembly, first tab, first adapter, second tab, second adapter, first electrode terminal, and second electrode terminal. Figure 1 ; Figure 9 This application provides schematic diagrams illustrating the structure of a battery cell after the connection of the electrode assembly, first tab, first adapter, second tab, second adapter, first electrode terminal, and second electrode terminal. Figure 2 ; Figure 10 This application provides schematic diagrams illustrating the structure of a battery cell after the connection of the electrode assembly, first tab, first adapter, second tab, second adapter, first electrode terminal, and second electrode terminal. Figure 3 ; Figure 11Schematic diagram of the internal structure of a battery cell provided in some embodiments of this application Figure 3 ; Figure 12 Schematic diagram of the internal structure of a battery cell provided in some embodiments of this application Figure 4 .

[0049] Explanation of reference numerals in the attached figures: 1000, Vehicle; 1100, Battery assembly; 1110, Housing; 1111, First part; 1112, Second part; 1113, Receiving space; 1120, Battery cell; 1121, Housing; 11211, Receiving cavity; 11212, First end wall; 1122, Electrode assembly; 1123, First adapter; 1124, First electrode terminal; 11241, First groove structure; 11242, First outer edge; 1125, First tab; 1126, Second tab; 1127, Second adapter; 1128, Second electrode terminal; 11281, Second groove structure; 11282, Second outer edge Along the edge; 1130, First welding area; 1140, Second welding area; 1141, First position; 1142, Second position; 1150, Third welding area; 1160, Fourth welding area; 1161, Third position; 1162, Fourth position; 1170, Lower plastic; 1180, Top cover; 1190, Pole post plastic; 1191, Pole post welding block; 1192, Sealing ring; 1193, Welding equipment; L1, First length; L2, Second length; L3, Third length; L4, Fourth length; 1200, Controller; 1300, Motor; X, First direction; Y, Second direction; Z, Third direction. Detailed Implementation

[0050] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application, and are therefore merely examples and should not be used to limit the scope of protection of this application.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[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] Lithium-ion batteries are widely used in new energy vehicles, energy storage devices, and other fields due to their advantages such as high energy density and long cycle life. As application scenarios increase the demand for battery power, the current-carrying capacity of individual battery cells has become one of the key factors affecting battery performance, and the ultrasonic welding area is the core component that determines the current-carrying capacity of individual battery cells.

[0059] In related technologies, the limitations of the connection between the electrode components and electrode terminals of a battery cell often affect the welding area, resulting in insufficient current carrying capacity of the battery cell, which in turn affects the performance of the battery cell.

[0060] Specifically, in related technologies, the connection between the electrode assembly and electrode terminals of a battery cell often uses an integrated adapter plate, combined with a longitudinal ultrasonic welding process. However, this structure has many limitations: on the one hand, longitudinal welding is limited by the vibration characteristics of the welding head, making it difficult to expand the welding area, resulting in insufficient current carrying capacity; on the other hand, the integrated adapter plate connects adjacent bare cells to each other through the adapter, which can easily generate tensile forces due to relative sliding during handling or use, causing the tabs to crack and affecting the performance of the battery cell.

[0061] Therefore, there is an urgent need for a battery cell that can increase the welding area and improve the current carrying capacity to ensure performance under high current conditions.

[0062] Therefore, this application provides a battery cell in which the adapter in the battery cell adopts a split structure, and each bare cell is connected to the electrode terminal through a separate adapter, so that a larger welding area can be formed between the adapter and the tab of the bare cell, thereby improving the overcurrent capacity between the electrode assembly and the electrode terminal.

[0063] Specifically, refer to Figure 3 As shown, this application embodiment provides a battery cell 1120, which includes a housing 1121, at least two first electrode terminals 1124, and at least two electrode assemblies 1122. The housing 1121 has a receiving cavity 11211 and a first end wall 11212. The first electrode terminals 1124 are disposed on the first end wall 11212. The electrode assemblies 1122 are disposed in the receiving cavity 11211, and each electrode assembly 1122 includes a first tab 1125. A first adapter 1123 corresponds to and matches the first tabs 1125 one by one. The first tabs 1125 of each electrode assembly 1122 are electrically connected to the first electrode terminals 1124 through the corresponding first adapter 1123.

[0064] In this embodiment of the application, the battery cell 1120 can be a secondary battery. A secondary battery refers to a battery cell 1120 that can be used again after being discharged by recharging to activate the active materials.

[0065] The battery cell 1120 can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and the embodiments of this application are not limited to this.

[0066] For electrode assembly 1122, which can be understood as a bare cell, electrode assembly 1122 is electrically connected to first electrode terminal 1124 through first adapter 1123. Electrode assembly 1122 includes a positive electrode (positive electrode sheet), a negative electrode (negative electrode sheet), and a separator, with the separator disposed between the negative and positive electrodes. During the charging and discharging process of battery cell 1120, active ions (e.g., lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, disposed between the positive and negative electrodes, prevents short circuits between the positive and negative electrodes while allowing active ions to pass through. Electrode assembly 1122 can be a wound structure, a stacked structure, or a hybrid structure of wound and stacked.

[0067] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0068] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material is disposed on either or both of the two opposite surfaces of the positive current collector.

[0069] As an example, the positive current collector can be a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as a metal foil, pure metals, alloys, or surface-treated metals can be used, including but not limited to stainless steel, copper, aluminum, nickel, titanium, or silver. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0070] As an example, the positive electrode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, and lithium manganese iron phosphate and carbon composites. Examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxides (such as LiCoO2), lithium nickel oxides (such as LiNiO2), lithium manganese oxides (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, lithium nickel cobalt manganese oxides (such as LiNi1 / 3Co1 / 3Mn1 / 3O2 (also abbreviated as NCM333), LiNi0.5Co0.2Mn0.3O2 (also abbreviated as NCM523), LiNi0.5Co At least one of the following: 0.25Mn0.25O2 (also abbreviated as NCM211), LiNi0.6Co0.2Mn0.2O2 (also abbreviated as NCM622), LiNi0.8Co0.1Mn0.1O2 (also abbreviated as NCM811), lithium nickel cobalt aluminum oxide (such as LiNi0.8Co0.15Al0.05O2), and their modified compounds. Modified compounds refer to substances obtained by doping or coating, etc., based on the above-mentioned materials.

[0071] In some embodiments, the positive electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. When foamed metal is used as the positive electrode, the surface of the foamed metal may or may not contain a positive electrode active material. As an example, a positive electrode active material is filled and / or deposited within the foamed metal.

[0072] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0073] As an example, the negative electrode current collector can be a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as a metal foil, pure metals, alloys, or surface-treated metals can be used, including but not limited to stainless steel, copper, aluminum, nickel, titanium, or silver. The composite current collector may include a polymer material substrate and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0074] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0075] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0076] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cell 1120. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials for battery cell 1120 may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0077] In some embodiments, the negative electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. When foamed metal is used as the negative electrode sheet, the surface of the foamed metal may or may not have a negative electrode active material.

[0078] As an example, negative electrode active materials can be filled or / and deposited within the negative electrode current collector.

[0079] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0080] In some embodiments, the electrode assembly 1122 further includes an isolator disposed between the positive and negative electrodes.

[0081] In some embodiments, the separator is a separator membrane. This application does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0082] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation. The separator can be a single component located between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes. An inorganic particle coating, an organic particle coating, or an organic / inorganic composite coating can also be applied to the surface of the separator.

[0083] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0084] The electrode assembly 1122 also includes tabs, which are internal current lead-out or lead-in terminals of the electrode assembly 1122 (bare cell). Tabs are core transitional components connecting the internal electrode plates of the cell to the external circuitry. The tabs are directly connected to the positive and negative electrode plates and are connected to the current collector, performing the function of current conduction during cell charging and discharging. In this example, the first tab 1125 can be either a positive or negative tab. When the first tab 1125 is a positive tab, then the first electrode terminal 1124 is a positive electrode terminal; when the second tab 1126 is a negative tab, then the first electrode terminal 1124 is a negative electrode terminal.

[0085] It should be noted that the tabs (first tab 1125 and second tab 1126) should be understood as tab clusters. The tab clusters are formed by multiple sheet-like structures stacked together. The tabs can be bent and form a mating surface to fit and connect with the adapters (first adapter 1123 and second adapter 1127).

[0086] Reference Figure 2 and Figure 3As shown, the number of first adapters 1123 is the same as the number of electrode assemblies 1122, so that the first tab 1125 in one electrode assembly 1122 is connected to the first adapter 1123 in a one-to-one correspondence. Each electrode assembly 1122 is connected to one first adapter 1123 through the first tab 1125. The first tab 1125 and the first adapter 1123 can be connected by welding. For example, the first tab 1125 and the first adapter 1123 can be connected by ultrasonic welding. Then, a welding area will be formed between the first tab 1125 and the first adapter 1123. The size of the welding area will affect the current flow area of ​​the battery cell 1120. Multiple first adapters 1123 are then connected to the first electrode terminal 1124.

[0087] Electrode terminals, also known as terminals, are provided in at least one battery cell 1120. These terminals are electrically connected to the tabs via adapters. (Refer to...) Figure 2 and Figure 3 As shown, in this example, the first electrode terminal 1124 is one of multiple electrode terminals. The first electrode terminal 1124 can be a positive electrode terminal (positive post) or a negative electrode terminal (negative post). The first electrode terminal 1124 is electrically connected to the first tab 1125 through the first adapter 1123. The first tab 1125 and the first adapter 1123 are connected by ultrasonic welding, and the first adapter 1123 and the first electrode terminal 1124 are connected by welding, such as laser welding.

[0088] As can be seen, relative to the entire battery cell 1120, the adapter in the battery cell 1120 adopts a split structure. Multiple electrode components 1122 use independent first adapters 1123. The first tab 1125 of each electrode component 1122 is independently connected to the first adapter 1123. The multiple first adapters 1123 in the multiple electrode components 1122 are independent of each other and do not share any one other.

[0089] Therefore, in the manufacturing process of the 1120 battery cell, referring to Figure 4As shown, an electrode assembly 1122 can be assembled and welded with a first adapter 1123 without requiring multiple electrode assemblies 1122 to be welded to an integrated adapter simultaneously. Therefore, the smallest welding unit on the welding equipment 1193 can be a first tab 1125 and a first adapter 1123, allowing the first tab 1125 and the first adapter 1123 to be welded laterally on the welding equipment 1193. This increases the length of the welding head (i.e., the assembly length of the first tab 1125 and the first adapter 1123 in the third direction Z described below), thereby increasing the welding length between the first tab 1125 and the first adapter 1123, and thus increasing the welding area to improve the current-carrying capacity between the first tab 1125 and the first adapter 1123.

[0090] It should be noted that the first tab 1125 has a preset length, which can be understood as the extension length of the electrode assembly 1122 in the length direction. For example, in one electrode assembly 1122, the first electrode terminal 1124 and the electrode assembly 1122 are arranged opposite each other in the first direction X. When the battery cell 1120 is placed vertically, the first direction X can be understood as the height direction of the battery cell 1120. The two electrode assemblies 1122 are arranged opposite each other in the second direction Y. The electrode assembly 1122 has a first tab 1125 (positive). The first electrode 1125 (positive electrode) and the second electrode 1126 (negative electrode) are arranged opposite each other in the third direction Z. Therefore, the preset length of the first electrode 1125 should be understood as its length in the third direction Z. The welding length between the first electrode 1125 and the first adapter 1123 should be understood as the welding length between them in the third direction Z. Multiplying the welding length by the welding width yields the welding area. The first direction X, the second direction Y, and the third direction Z are all perpendicular to each other. Increasing the length of the welding head of the welding equipment 1193 in the third direction Z increases the welding length between the first electrode 1125 and the first adapter 1123 in the third direction Z.

[0091] Therefore, it needs to be explained that using an integrated adapter plate requires the tabs of multiple electrode assemblies 1122 to be connected to the adapter plate, resulting in a large overall structural space. Due to the limited welding space, welding can only be done longitudinally. Longitudinal welding refers to a welding method where the ultrasonic vibration direction of the welding head is parallel and in the same direction as the welding pressure direction. It can also be understood as a welding process where the vibration is transmitted along the thickness direction or stacking direction of the tab. In this case, even if the welding length of the welding head is increased, incomplete welds are easily formed in the areas near both ends of the welding length, resulting in poor welding reliability. The effective welding area does not increase significantly, making it unsuitable for applications requiring large-area welding. However, referring to... Figure 4 As shown, this application adopts a split first adapter 1123, which allows the first electrode 1125 and the first adapter 1123 to be welded laterally. Lateral welding refers to a welding method in which the ultrasonic vibration direction of the welding head is perpendicular to the welding pressure direction, also known as shear vibration welding. Its vibration is transmitted along the plane direction of the first electrode 1125. In this case, increasing the welding length of the welding head can increase the length of the welding area (the length in the third direction Z) and is less likely to produce incomplete welds, thereby effectively increasing the welding area and improving the current carrying capacity.

[0092] Furthermore, when multiple electrode assemblies 1122 share a single adapter, during transport, excessively fast movement of the robotic arm or loosening of the grippers can easily cause the electrode assemblies 1122 to slide relative to each other. The tabs of two or more electrode assemblies 1122 may be subjected to pulling forces from the tabs on either side, leading to cracking between the tabs and the adapter. In this example, the structure of one electrode assembly 1122 connected to one first adapter 1123 reduces the mutual pulling problem when multiple electrode assemblies 1122 are connected to a single adapter during transport, thus lowering the risk of cracking between the first tab 1125 and the first adapter 1123.

[0093] Typically, the outer casing 1121 is an empty shell structure, with an internal accommodating cavity 11211 formed inside. The electrode assembly 1122 and the first electrode tab 1125 are both housed within this cavity 11211. The first electrode terminal 1124 is connected to the outer casing 1121. Specifically, the outer casing 1121 has a first end wall 11212, which can be considered as part of the casing wall of the outer casing 1121. For example, a portion of the first electrode terminal 1124 can be housed within the cavity 11211, while another portion can be exposed (or protrude) from the first end wall 11212. The outer casing 1121 can be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite casing 1121), or aluminum-plastic film, etc. In some embodiments, the outer casing 1121 can be a sealed structure or a non-sealed structure. As an example, when the outer casing 1121 is a non-sealed structure, it serves to protect the electrode assembly 1122. A sealing bag may also be included between the outer casing 1121 and the electrode assembly 1122, used to encapsulate the electrode assembly 1122 and the electrolyte. Specifically, the sealing bag can be a bag-shaped insulating component or an aluminum-plastic film. When the outer casing 1121 is a sealed structure, it is used to encapsulate the electrode assembly 1122 and the electrolyte, among other components.

[0094] In this embodiment, by replacing the traditional integrated adapter piece with a separate first adapter 1123, a first adapter 1123 is welded to the first tab 1125 on an electrode assembly 1122. This allows the connection between the first tab 1125 and the first adapter 1123 to be ultrasonically welded using a transverse welding process. Combined with increasing the length of the welding head, the welding length between the first tab 1125 and the first adapter 1123 can be increased, thereby increasing the welding area and improving the current carrying capacity between the first tab 1125 and the first adapter 1123. In addition, compared with traditional longitudinal welding, the design of the separate first adapter 1123 reduces the mutual pulling problem caused by multiple electrode assemblies 1122 being connected through the same adapter, which is beneficial to improving the connection stability between the electrode assembly 1122, the first adapter 1123, and the first electrode terminal 1124.

[0095] In some embodiments, refer to Figure 3 As shown, along the first direction X, the end of the first electrode terminal 1124 facing the electrode assembly 1122 and having the first tab 1125 is disposed (which can also be understood as the first electrode terminal 1124 and each electrode assembly 1122 being disposed opposite to each other in the first direction X). Multiple electrode assemblies 1122 are stacked sequentially in the second direction Y, which is perpendicular to the first direction X. In the second direction Y, multiple first adapters 1123 are disposed sequentially, and any two adjacent first adapters 1123 are spaced apart in the second direction Y.

[0096] Specifically, for the prismatic battery cell 1120, the first direction X can be understood as the height direction of the electrode assembly 1122 or the battery cell 1120, the second direction Y can be understood as the width direction of the electrode assembly 1122, and the third direction Z can be understood as the length direction of the electrode assembly 1122 or the battery cell 1120. It should be noted that "perpendicular" should be understood as basically perpendicular, and should not be limited to perpendicularity in a strict sense, and is not affected by the verticality accuracy.

[0097] The following explanation uses a single battery cell 1120, which includes two electrode assemblies 1122, as an example. Figure 3 As shown, two electrode assemblies 1122 are stacked in the second direction Y. Each of the two electrode assemblies 1122 extends outward from the upper part (or top) of the first electrode tab 1125. The upper parts of the two first electrode tabs 1125 are respectively overlapped and welded to the first adapter 1123. The two first adapters 1123 are then respectively welded to the first electrode terminal 1124. The two first adapters 1123 are spaced apart to reduce the risk of interference between the two first adapters 1123.

[0098] In addition, compared to the integral adapter, the split first adapter 1123 is smaller in size, which can reduce the amount of material consumed in manufacturing the adapter and reduce manufacturing costs.

[0099] Furthermore, considering that when the integrated adapter piece is used for lateral welding, for products with an electrode assembly 1122 (bare cell or JR) height ≥ 110mm, the welding equipment 1193 will interfere with the fixture of the electrode assembly 1122, making industrial production impossible. However, by using two separate first adapter pieces 1123, the electrode assembly 1122 can be arranged "back to back" (first tab 1125 facing the welding equipment 1193). The space between the two first adapter pieces 1123 provides an independent operating channel for the ultrasonic welding head, which can perform lateral welding on the two first tabs 1125 separately without avoiding the fixture. Even when the height of the electrode assembly 1122 is ≥ 110mm, welding can be completed smoothly, removing the limitation on welding height.

[0100] In addition, the two first adapters 1123 are arranged at intervals to form a natural heat dissipation gap, which can quickly dissipate the heat generated by welding, reduce the thermal impact between the two adjacent first adapters 1123, and prevent subsequent assembly or performance problems caused by molten metal sticking together.

[0101] Furthermore, the space between the two first adapter pieces 1123 allows for minor adjustments to equipment components such as welding heads and fixtures, reducing the extreme requirements for welding positioning accuracy (such as the parallelism of bare cell stacking and the coaxiality of adapter piece assembly). Even if there are minor deviations, they can be compensated by the space, reducing the risk of incomplete or missing welds caused by positioning errors and improving process stability during mass production.

[0102] Furthermore, the two first adapters 1123 are spaced apart, so that the current paths of the two first adapters 1123 are independent of each other. The current is directly conducted from their respective first tabs 1125 → first adapters 1123 → first electrode terminals 1124, which is not easy to form cross-congestion. Combined with the low resistance advantage of the large horizontal welding area, it is conducive to further improving the overall current carrying capacity.

[0103] In this embodiment, any two adjacent first adapters 1123 are spaced apart in the second direction Y, which can reduce the risk of interference when assembling with the first electrode terminal 1124, and also save the manufacturing materials of the adapters, improve the heat dissipation effect, and further improve the current carrying capacity.

[0104] In some embodiments, refer to Figure 3 and Figure 4As shown, along the first direction X, the first electrode terminal 1124 is disposed at one end facing the electrode assembly 1122 and having a first tab 1125. Multiple electrode assemblies 1122 are stacked sequentially in the second direction Y. In the third direction Z, the first adapter 1123 has a first length L1. The first tab 1125 is welded to the first adapter 1123 to form a first welding area 1130. The first welding area 1130 has a second length L2 in the third direction Z, and the second length L2 is 50%-100% of the first length L1. The first direction X, the second direction Y, and the third direction Z are all perpendicular to each other.

[0105] Specifically, the length direction of the battery cell 1120 is in the third direction Z. In the third direction Z, the first adapter 1123 has a first length L1. The first adapter 1123 and the first tab 1125 are stacked and welded together in the first direction X. The welding method is ultrasonic welding, so that the first tab 1125 and the first adapter 1123 form a first welding area 1130 (i.e., the welding area formed by ultrasonic welding) in the overlapping part. In the third direction Z, the first welding area 1130 has a second length L2. For example, the first welding area 1130 is a regular shape, such as a rectangular area. Then, the second length L2 is the length of one side of the rectangle in the third direction Z.

[0106] The second length L2 is 50%-100% of the first length L1. That is, the length of the first welding area 1130 is 50%-100% of the length of the first adapter 1123. The extension dimension of the first welding area 1130 in the length direction (i.e., the third direction Z) accounts for more than 50% of the length of the first adapter 1123 in that direction. It can be seen that the welding area between the first tab 1125 and the first adapter 1123 can be greatly increased.

[0107] During the welding process between the first tab 1125 and the first adapter 1123, the vibration direction of the welding head is set along the third direction Z (or the second direction Y) (i.e., transverse welding method) to ensure that the welding area can extend sufficiently in the third direction Z, so that the second length L2 reaches 50%-100% of the first length L1. The welding method in this example is different from the longitudinal welding in related technologies, which can effectively increase the welding area and reduce the risk of incomplete welding.

[0108] In this embodiment, a first tab 1125 is matched and connected to a first adapter 1123, so that the first tab 1125 and the first adapter 1123 can be welded laterally and form a first welding area 1130 with a length exceeding 50% of the length of the first adapter 1123, so as to increase the effective welding area and thereby improve the current carrying capacity between the first tab 1125 and the first adapter 1123.

[0109] In some embodiments, refer to Figure 5 As shown, along the first direction X, one end of the first electrode terminal 1124 facing the electrode assembly 1122 is provided with a first tab 1125; along the first direction X, one end of the first electrode terminal 1124 facing each first tab 1125 (or electrode assembly 1122) is provided with a first groove structure 11241 corresponding to each first adapter 1123, and the first adapter 1123 is at least partially accommodated in the first groove structure 11241.

[0110] Specifically, the first electrode terminal 1124 and each electrode assembly 1122 are arranged opposite to each other in the first direction X, that is, the first direction X is the relative orientation direction of the two (such as the vertical direction).

[0111] Along the first direction X, one end of the first electrode terminal 1124 facing each electrode assembly 1122 (i.e., the end of the first electrode terminal 1124 extending into the receiving cavity 11211) is provided with a first groove structure 11241 corresponding to each first adapter 1123. The shape and size of the first groove structure 11241 are adapted to the shape and size of the connecting portion of the first adapter 1123, ensuring that the first adapter 1123 can be at least partially accommodated within the first groove structure 11241. The depth of the first groove structure 11241 can be set according to assembly requirements, as long as it can achieve partial accommodation of the first adapter 1123. For example, if the connecting portion of the first adapter 1123 is sheet-like with a thickness of H1, and the thickness of the first groove structure 11241 in the first direction X is H2, then H1 can be greater than or equal to H2, or H1 can be less than H2.

[0112] It should be noted that the groove depth of the first groove structure 11241 is along the first direction X, and the groove wall of the first groove structure 11241 facing the first adapter 1123 should be through, so that the first adapter 1123 can extend from the inside of the first groove structure 11241 through the through groove wall to the outside of the first groove structure 11241 and then connect with the first tab 1125.

[0113] One end of the first adapter 1123 is welded and fixed to the first tab 1125, and the other end is at least partially embedded in the first groove structure 11241 of the first electrode terminal 1124. Then, the first adapter 1123 is fixedly connected to the inner wall or bottom of the first groove structure 11241 by laser welding to achieve electrical connection between the two. The first groove structure 11241 plays a positioning and limiting role for the first adapter 1123, reducing the risk of the first adapter 1123 shifting during welding. In addition, in the first direction X, the first adapter 1123 is housed in the first groove structure 11241, thereby saving more space in the first direction X. The electrode portion (or the wound body or the stacked body) of the electrode assembly 1122 can have a greater height, which is beneficial to improving the energy density of the battery cell 1120.

[0114] Regarding the design of the first groove structure 11241 in this application, the first groove structure 11241 serves to position the first adapter 1123. During the welding assembly process, it can quickly achieve precise alignment between the first adapter 1123 and the first electrode terminal 1124, reducing welding defects caused by alignment deviations. In addition, the first adapter 1123 is partially housed within the first groove structure 11241, increasing the contact area between the two. Furthermore, the first groove structure 11241 can restrict the displacement of the first adapter 1123 in the horizontal direction (perpendicular to the first direction X), improving the stability of the connection structure and reducing the problem of loosening of the connection caused by vibration and other factors during the operation of the battery cell 1120.

[0115] Furthermore, the first adapter 1123 is partially housed within the first recessed structure 11241 of the first electrode terminal 1124. Compared to a planar connection where the two are completely fitted together, this embedded structure effectively reduces the space occupied by both in the first direction X. With the volume of the housing 1121 of the battery cell 1120 remaining fixed, the saved internal space can be used to accommodate a larger electrode assembly 1122 or increase the capacity of the winding body of the electrode assembly 1122, thereby improving the energy density of the battery cell 1120.

[0116] Furthermore, the first groove structure 11241 makes the contact between the first adapter 1123 and the first electrode terminal 1124 tighter and reduces the contact resistance. In addition, the embedded connection method makes the current conduction path more regular, reduces the local heating problem caused by poor contact, enhances the smoothness of current conduction, and further ensures the overcurrent performance and operational stability of the battery cell 1120.

[0117] In this embodiment, by setting the first groove structure 11241, the first adapter 1123 can be limited and positioned, which is conducive to improving space utilization and increasing the energy density of the battery cell 1120.

[0118] In some embodiments, refer to Figure 8 As shown, along the first direction X, the end of the first electrode terminal 1124 facing the electrode assembly 1122 is provided with a first tab 1125. Multiple electrode assemblies 1122 are stacked sequentially in the second direction Y, which is perpendicular to the first direction X. Each first tab 1125 is welded to each first adapter 1123 at a first position 1141 to form a first welding area 1130. The first electrode terminal 1124 is welded to each first adapter 1123 at a second position 1142 to form a second welding area 1140. In the second direction Y, the extended portion of the first electrode terminal 1124 connected to the first adapter 1123 extends beyond the first position 1141, so that the first welding area 1130 and the second welding area 1140 have at least an overlapping portion.

[0119] Specifically, the setting of the first direction X and the second direction Y, the positional relationship between the first electrode terminal 1124 and the electrode assembly 1122, and the arrangement of the multiple electrode assemblies 1122 can be referred to the above example, and will not be repeated here.

[0120] Each first electrode tab 1125 is welded to each first adapter 1123 at a first position 1141 to form a first welding area 1130, which is an ultrasonic welding area; the first electrode terminal 1124 is welded to each first adapter 1123 at a second position 1142 to form a second welding area 1140, which is a laser welding area.

[0121] In the second direction Y, the extended portion of the first electrode terminal 1124 connected to the first adapter 1123 extends beyond the first position 1141, so that the first welding area 1130 and the second welding area 1140 have at least an overlapping portion, that is, the projection area of ​​the first welding area 1130 in the first direction X and the projection area of ​​the second welding area 1140 in the first direction X have an overlapping portion, that is, the second welding area 1140 of laser welding covers part or all of the first welding area 1130 of ultrasonic welding, and there is an overlapping area between the two.

[0122] Since the extended portion of the first electrode terminal 1124 connected to the first adapter 1123 extends beyond the first position 1141, it is known that the first electrode terminal 1124 has a larger extension length. Part of the current flow path on the first adapter 1123 is transferred to the first electrode terminal 1124. It is known that the first electrode terminal 1124 has better current carrying capacity. Therefore, this design can improve the current carrying capacity and effect between the electrode assembly 1122 and the first electrode terminal 1124.

[0123] In addition, the first welding area 1130 and the second welding area 1140 partially overlap, which allows laser welding to further strengthen the connection strength of ultrasonic welding. The coverage of the ultrasonic welding area by laser welding further enhances the connection firmness. Furthermore, the overlap of the first welding area 1130 and the second welding area 1140 forms a double-reinforced structure for the connection of the first tab 1125, the first adapter 1123, and the first electrode terminal 1124. This not only improves the mechanical connection strength but also increases the conductive contact area, reduces the contact resistance, and ensures the reliability of current conduction.

[0124] In some embodiments, refer to Figure 9 As shown, the extended portion of the first electrode terminal 1124 connected to the first adapter 1123 avoids the first position 1141, so that the first welding area 1130 and the second welding area 1140 are spaced apart.

[0125] Specifically, in the second direction Y, the extended portion of the first electrode terminal 1124 connected to the first adapter 1123 avoids the first position 1141, so that the first welding area 1130 and the second welding area 1140 are spaced apart. That is, there is a gap between the second welding area 1140 of laser welding and the first welding area 1130 of ultrasonic welding, and the two do not overlap.

[0126] Reliable electrical connections can be achieved through ultrasonic welding of the first tab 1125 to the first adapter 1123 and laser welding of the first adapter 1123 to the first electrode terminal 1124. The two welding areas are set up independently, which reduces the risk of damage to the ultrasonic welding area caused by the high temperature of laser welding.

[0127] This embodiment provides two positioning schemes for the welding areas, which can be selected according to the actual production process, material characteristics, and performance requirements. For scenarios where the ultrasonic welding area is sensitive to high temperatures, the avoidance method shown in this example can be selected. This avoidance setting reduces the risk of damage caused by the high temperatures of laser welding, ensuring welding quality and improving the flexibility and adaptability of product design. The spacing between the two welding areas reduces the risk of mutual interference between different welding processes, and each welding area can maintain its independent connection performance, thus ensuring the reliability of the overall connection.

[0128] In this embodiment, the overlapping of the first welding area 1130 and the second welding area 1140 can improve the reliability of the connection. The alternating arrangement of the first welding area 1130 and the second welding area 1140 is suitable for situations sensitive to high-temperature laser welding and can reduce mutual interference between different welding methods.

[0129] In some embodiments, refer to Figure 10As shown, along the first direction X, the end of the first electrode terminal 1124 facing the electrode assembly 1122 is provided with the first tab 1125. Multiple electrode assemblies 1122 are stacked sequentially in the second direction Y, which is perpendicular to the first direction X. The first electrode terminal 1124 is welded to each of the first adapters 1123 at the second position 1142 to form a second welding area 1140. The second welding area 1140 spans between any two adjacent first adapters 1123.

[0130] Specifically, the settings of the first direction X and the second direction Y, the positional relationship between the first electrode terminal 1124 and the electrode assembly 1122, and the arrangement of the multiple electrode assemblies 1122 can be referred to the above example, and will not be repeated here.

[0131] The first electrode terminal 1124 is welded to each of the first adapters 1123 at the second position 1142 to form a second welding area 1140, which is a laser welding area. In the second direction Y, the second welding area 1140 spans between any two adjacent first adapters 1123. That is, a single second welding area 1140 simultaneously covers the ends of two adjacent first adapters 1123 and is welded and fixed to the first electrode terminal 1124, achieving electrical connection between two adjacent first adapters 1123 and the first electrode terminal 1124 through the same laser welding area.

[0132] Two adjacent first adapters 1123 are spaced apart in the second direction Y, and the distance between them may be less than the length of the second welding area 1140 (along the second direction Y). During laser welding, the weld mark spans the connection surface between the ends of the two adjacent first adapters 1123 and the first electrode terminal 1124, so that the two adjacent first adapters 1123 simultaneously form a reliable electrical connection with the first electrode terminal 1124 through the spanning second welding area 1140. In addition, the two adjacent first adapters 1123 are also indirectly electrically connected to each other through the second welding area 1140.

[0133] In this case, multiple second welding areas 1140 can be provided, and multiple second welding areas 1140 are arranged sequentially at intervals in the third direction Z, so that the first adapter 1123 and the first electrode terminal 1124 have a larger welding area in the length direction (i.e., the third direction Z) to improve the firmness between the first adapter 1123 and the first electrode terminal 1124.

[0134] In this embodiment, a single second welding area 1140 spans two adjacent first adapters 1123, so that the two adjacent first adapters 1123 and the first electrode terminal 1124 form an integral connection structure. This not only improves the connection strength between each first adapter 1123 and the first electrode terminal 1124, but also enhances the cooperative stability between adjacent first adapters 1123, reducing the problem of overall performance degradation caused by loose connection of a single first adapter 1123.

[0135] Furthermore, the transverse second welding area 1140 allows for partial current diversion between the two adjacent first adapters 1123, reducing the problem of excessive current concentration in a single first adapter 1123. Simultaneously, the integral welding area ensures a more balanced path for current conduction from the two first adapters 1123 to the first electrode terminal 1124, reducing local impedance differences during current conduction, improving the uniformity of current conduction, lowering the risk of excessive localized heating, and ensuring the operational stability of the battery cell 1120.

[0136] Furthermore, in this embodiment, a single second welding area 1140 can simultaneously complete the welding of two adjacent first adapters 1123, reducing the number of laser welding operations. This reduction in welding operations not only lowers process operation time but also reduces energy and material consumption during the welding process, significantly improving production efficiency and lowering industrial production costs.

[0137] In this embodiment, the second welding area 1140 spans between two adjacent first adapters 1123, which can enhance the cooperative stability between adjacent first adapters 1123, improve the current uniformity, and ensure the working stability of the battery cell 1120.

[0138] In some embodiments, refer to Figure 5 As shown, there are two electrode assemblies 1122. Along the first direction X, the first electrode terminal 1124 is provided at the end of the electrode assembly 1122 that is provided with the first tab 1125. In the second direction Y, the first electrode terminal 1124 is provided with two protruding first outer edges 11242, and the two first outer edges 11242 are respectively electrically connected to the two first adapters 1123. The first direction X is perpendicular to the second direction Y.

[0139] Specifically, there are two electrode assemblies 1122, both of which are housed in the receiving cavity 11211 of the housing 1121 and are stacked sequentially along the second direction Y (perpendicular to the first direction X) (see the example above). Each electrode assembly 1122 is provided with a first tab 1125 for connecting to the corresponding first adapter 1123.

[0140] The first electrode terminal 1124 and the electrode assembly 1122 (i.e., the first tab 1125) are disposed opposite each other in the first direction X. In the second direction Y, the first electrode terminal 1124 has two protruding first outer edges 11242. For example, the first electrode terminal 1124 includes a first cylindrical portion located in the middle and first outer edges 11242 connected to both sides of the first cylindrical portion. The two first outer edges 11242 are respectively stacked and welded to the two first adapters 1123. The first outer edge 11242 is a protruding structure formed by the first cylindrical portion extending in the second direction Y. The extension direction of the first outer edge 11242 is consistent with the stacking direction of the two electrode assemblies 1122.

[0141] One end of each of the two first adapters 1123 is ultrasonically welded to the first tabs 1125 of the two electrode assemblies 1122. Then, the other ends of the two first adapters 1123 are laser welded to the two first outer edges 11242 of the first electrode terminal 1124, forming two independent current conduction paths of "electrode assembly 1122 - first adapter 1123 - first outer edge 11242 - first electrode terminal 1124 body", ultimately realizing the parallel electrical connection between the two electrode assemblies 1122 and the external circuit.

[0142] In this example, for the configuration of the two electrode assemblies 1122, the two first outer edges 11242 of the first electrode terminal 1124 protrude outward along the second direction Y, which can accurately adapt to the arrangement position of the two first adapters 1123, reducing the internal space occupation problem caused by the excessive size of the first column portion of the first electrode terminal 1124. The protruding first outer edges 11242 allow the connection position of the first adapter 1123 and the first electrode terminal 1124 to be closer to the first tab 1125 of the electrode assembly 1122, shortening the current conduction path and reducing the conduction impedance.

[0143] Furthermore, the two first outer edges 11242 are respectively connected to the two first adapters 1123 in a one-to-one correspondence, making the structures of the two current conduction paths completely symmetrical. This symmetrical structure ensures uniform current distribution between the two electrode assemblies 1122, reducing current imbalance caused by path differences and guaranteeing the operational stability of the battery cell 1120. Additionally, the protruding structure of the first outer edge 11242 increases the contact area with the first adapter 1123, improving the reliability of the welded connection and reducing the risk of loosening.

[0144] Of course, the electrode assembly 1122 can also be provided in three, four, etc. In general, an even number of electrode assemblies 1122 are more commonly used to form a symmetrical arrangement, which is conducive to achieving uniformity of flow conduction.

[0145] Furthermore, the use of two electrode assemblies 1122 also facilitates the ultrasonic welding of the first tab 1125 and the first adapter 1123 by arranging the two electrode assemblies 1122 back to back, allowing simultaneous welding on two fluxes, thereby improving welding efficiency.

[0146] In this embodiment, the two electrode assemblies 1122 are arranged in a configuration that allows the two electrode assemblies 1122 to be symmetrically arranged on both sides of the first electrode terminal 1124. The connection between the first adapter 1123 and the first electrode terminal 1124 is also more reliable, which helps to improve the stability of the entire battery cell 1120.

[0147] In some embodiments, refer to Figure 11 As shown, the battery cell 1120 also includes a second electrode terminal 1128 and a second adapter 1127. The second electrode terminal 1128 is disposed on the first end wall 11212 (i.e., connected to the housing 1121 and at least partially exposed on the outer surface of the housing 1121). The second electrode terminal 1128 and the first electrode terminal 1124 are arranged at intervals. Each electrode assembly 1122 also includes a second tab 1126. The second tab 1126 of each electrode assembly 1122 is electrically connected to the second electrode terminal 1128 through the second adapter 1127.

[0148] Specifically, when the first electrode terminal 1124 is a positive electrode terminal (positive post), then the second electrode terminal 1128 can be understood as a negative electrode terminal (negative post); when the first electrode terminal 1124 is a negative electrode terminal (negative post), then the second electrode terminal 1128 can be understood as a positive electrode terminal (positive post), and the polarities of the first electrode terminal 1124 and the second electrode terminal 1128 are opposite. In the following example, the first electrode terminal 1124 is a positive electrode terminal and the second electrode terminal 1128 can be understood as a negative electrode terminal. Correspondingly, the first tab 1125 is a positive tab and the second tab 1126 is a negative tab.

[0149] The second electrode terminal 1128 is connected to the housing 1121, and its assembly position is spaced apart from that of the first electrode terminal 1124. The first electrode terminal 1124 and the second electrode terminal 1128 can be symmetrically arranged at both ends of the top cover 1180 of the housing 1121 to optimize the current conduction path and internal space layout. The second electrode terminal 1128 is at least partially exposed on the outer surface of the housing 1121. The exposed part is used to establish an electrical connection with the other pole of the external circuit, and works with the first electrode terminal 1124 to realize the input and output of charging and discharging current of the battery cell 1120. The second electrode terminal 1128 is also made of a metal material with excellent conductivity, such as copper, aluminum or their alloys. The material selection can be determined according to the polarity requirements and conductivity requirements of the battery cell 1120 to ensure stable current conduction in conjunction with the first electrode terminal 1124.

[0150] The following combination Figure 4 as well as Figure 6-8 As shown, each electrode assembly 1122 also includes a second tab 1126. The second tab 1126 and the first tab 1125 are tabs of different polarities in the electrode assembly 1122 (e.g., the first tab 1125 is the positive tab, and the second tab 1126 is the negative tab). Both are conductive extensions in the electrode assembly 1122 used to realize current conduction / induction. They are integrally formed or fixedly connected to the cell body (or winding body or stacked body) of the electrode assembly 1122 and are made of conductive materials adapted to the corresponding polarity. The second tab 1126 is positioned alternately from the first tab 1125 to avoid short circuits during assembly and operation, ensuring that the positive and negative currents of the electrode assembly 1122 can be conducted independently and smoothly.

[0151] Multiple second adapters 1127 are provided, and each second adapter 1127 is matched with a corresponding second tab 1126, that is, one second adapter 1127 is connected to one second tab 1126 of an electrode assembly 1122. The second tab 1126 of each electrode assembly 1122 is electrically connected to the second electrode terminal 1128 through the corresponding second adapter 1127, forming a current conduction path of "electrode assembly 1122 - second adapter 1127 - second electrode terminal 1128", which, together with the aforementioned path of "electrode assembly 1122 - first adapter 1123 - first electrode terminal 1124", constitutes the complete current loop of the battery cell 1120. The second adapter 1127 adopts the same split structure design as the first adapter 1123, ensuring that each second adapter 1127 independently undertakes the conductive connection function between the second tab 1126 and the second electrode terminal 1128 of the corresponding electrode assembly 1122.

[0152] The second electrode tab 1126 of each electrode assembly 1122 is fixedly connected to the corresponding second adapter 1127 by ultrasonic welding. The welding process ensures full contact between the welding surfaces to reduce the risk of poor welding. In addition, each second adapter 1127 is fixedly connected to the second electrode terminal 1128 by laser welding, thus forming a complete negative (or positive) current conduction circuit.

[0153] Based on the above-mentioned multiple electrode assemblies 1122 using independent first adapters 1123, the multiple electrode assemblies 1122 also use independent second adapters 1127. The second tabs 1126 of each electrode assembly 1122 are independently connected to the second adapters 1127. The multiple second adapters 1127 in the multiple electrode assemblies 1122 are independent of each other and do not share any one other. Therefore, during the manufacturing process of the battery cell 1120, one electrode assembly 1122 can be assembled and welded with one second adapter 1127, without the need for multiple electrode assemblies 1122 to be welded to an integrated adapter simultaneously. Thus, the smallest welding unit on the welding equipment 1193 can be a second tab 1126 and a second adapter 1127, so that the second tab 1126 and the second adapter 1127 can be laterally welded on the welding equipment 1193, increasing the length of the welding head (i.e., the assembly length of the second tab 1126 and the second adapter 1127 in the third direction Z), thereby increasing the welding length between the second tab 1126 and the second adapter 1127, and thus increasing the welding area to improve the current carrying capacity between the second tab 1126 and the second adapter 1127.

[0154] This application employs a split-type second adapter 1127, enabling the second electrode 1126 and the second adapter 1127 to also be welded laterally. Lateral welding refers to a welding method where the ultrasonic vibration direction of the welding head is perpendicular to the welding pressure direction, also known as shear vibration welding, where the vibration is transmitted along the plane of the second electrode 1126. In this case, increasing the welding length of the welding head can increase the length of the welding area (the length in the third direction Z), and it is less likely to produce incomplete welds, thereby effectively increasing the welding area and improving the current carrying capacity.

[0155] The welding process parameters of the second adapter 1127, the second tab 1126, and the second electrode terminal 1128 can refer to the welding parameters of the first adapter 1123 to ensure welding quality and electrical reliability. At the same time, the spacing arrangement reduces short-circuit interference between the second electrode terminal 1128 and the first electrode terminal 1124, and between the second adapter 1127 and the first adapter 1123.

[0156] In addition, the structure of one electrode assembly 1122 connecting to one second adapter 1127 reduces the mutual pulling problem when multiple electrode assemblies 1122 are connected to one adapter during transportation, and reduces the risk of cracking between the second tab 1126 and the second adapter 1127.

[0157] In this embodiment, based on the design of the split first adapter 1123, a split second adapter 1127 is further adopted between the second tab 1126 and the second electrode assembly 1122. One second adapter 1127 is welded to the second tab 1126 on one electrode assembly 1122, so that the connection position between the second tab 1126 and the second adapter 1127 can be ultrasonically welded using a transverse welding process. Combined with increasing the length of the welding head, the welding length between the second tab 1126 and the second adapter 1127 can be increased, thereby increasing the welding area and improving the current carrying capacity between the second tab 1126 and the second adapter 1127. Compared with traditional longitudinal welding, the design of the split second adapter 1127 reduces the mutual pulling problem caused by multiple electrode assemblies 1122 being connected through the same adapter, which is beneficial to improving the connection stability between the electrode assembly 1122, the second adapter 1127, and the second electrode terminal 1128.

[0158] In some embodiments, refer to Figure 11 As shown, along the first direction X, the second electrode terminal 1128 is disposed toward the end of the electrode assembly 1122 that is provided with the second tab 1126. Multiple electrode assemblies 1122 are stacked sequentially in the second direction Y, which is perpendicular to the first direction X. In the second direction Y, multiple second adapters 1127 are disposed sequentially, and any two adjacent second adapters 1127 are arranged at intervals in the second direction Y.

[0159] Similarly, for the prismatic battery cell 1120, the first direction X can be understood as the height direction of the electrode assembly 1122 or the battery cell 1120, the second direction Y can be understood as the width direction of the electrode assembly 1122, and the third direction Z can be understood as the length direction of the electrode assembly 1122 or the battery cell 1120.

[0160] Taking a single battery cell 1120 including two electrode assemblies 1122 as an example, the two electrode assemblies 1122 are stacked in the second direction Y. Each of the two electrode assemblies 1122 has a second tab 1126 extending outward from its upper part (or top). The upper parts of the two second tabs 1126 are respectively overlapped and welded with second adapters 1127. The two second adapters 1127 are then respectively welded to the second electrode terminals 1128. The two second adapters 1127 are spaced apart to reduce the risk of interference between the two second adapters 1127.

[0161] In addition, compared to the integral adapter, the split second adapter 1127 is smaller in size, which can reduce the amount of material consumed in manufacturing the adapter and reduce manufacturing costs.

[0162] Furthermore, considering that when the integrated adapter piece is used for lateral welding, for products with an electrode assembly 1122 (bare cell or JR) height ≥ 110mm, the welding equipment 1193 will interfere with the fixture of the electrode assembly 1122, making industrial production impossible. However, by using two separate second adapter pieces 1127, the electrode assembly 1122 can be arranged "back to back" (second tab 1126 facing the welding equipment 1193). The space between the two second adapter pieces 1127 provides an independent operating channel for the ultrasonic welding head, which can perform lateral welding on the two second tabs 1126 separately without avoiding the fixture. Even when the height of the electrode assembly 1122 is ≥ 110mm, welding can be completed smoothly, removing the limitation on welding height.

[0163] In addition, the two first adapters 1123 are arranged at intervals to form a natural heat dissipation gap, which can quickly dissipate the heat generated by welding, reduce the thermal impact between the two adjacent first adapters 1123, and prevent subsequent assembly or performance problems caused by molten metal sticking together.

[0164] Furthermore, the space between the two second adapters 1127 allows for minor adjustments to equipment components such as welding heads and fixtures, reducing the extreme requirements for welding positioning accuracy (such as the parallelism of bare cell stacking and the coaxiality of adapter assembly). Even if there are minor deviations, they can be compensated by the space, reducing the risk of incomplete or missing welds caused by positioning errors and improving process stability during mass production.

[0165] Furthermore, the two second adapters 1127 are spaced apart, making their current paths independent. The current flows directly from their respective second tabs 1126 → second adapters 1127 → second electrode terminals 1128, making it less prone to cross-congestion. Combined with the low resistance advantage of the large horizontal welding area, this further enhances the overall current carrying capacity.

[0166] In this embodiment, any two adjacent second adapters 1127 are spaced apart in the second direction Y, which can reduce the risk of interference when assembling with the second electrode terminal 1128, and also save the manufacturing materials of the adapters, improve the heat dissipation effect, and further improve the current carrying capacity.

[0167] In some embodiments, refer to Figure 11As shown, along the first direction X, the second electrode terminal 1128 is disposed towards the end of the electrode assembly 1122 that has the second tab 1126, and multiple electrode assemblies 1122 are stacked sequentially in the second direction Y; refer to Figure 4 As shown, in the third direction Z, the second adapter 1127 has a third length L3; the second tab 1126 is welded to the second adapter 1127 to form a third welding area 1150, the third welding area 1150 has a fourth length L4 in the third direction Z, the fourth length L4 is 50%-100% of the third length L3; the first direction X, the second direction Y and the third direction Z are mutually perpendicular.

[0168] Specifically, the length direction of the battery cell 1120 is in the third direction Z. In the third direction Z, the second adapter 1127 has a third length L3. The second adapter 1127 and the second tab 1126 are stacked and welded together in the first direction X. The welding method is ultrasonic welding, so that the second tab 1126 and the second adapter 1127 form a third welding area 1150 (i.e., the welding area formed by ultrasonic welding) in the overlapping part. In the third direction Z, the third welding area 1150 has a fourth length L4. For example, the third welding area 1150 is a regular shape, such as a rectangular area. Then, the fourth length L4 is the length of one side of the rectangle in the third direction Z.

[0169] The fourth length L4 is 50%-100% of the third length L3. That is, the length of the third welding area 1150 is 50%-100% of the length of the second adapter 1127. The extension dimension of the third welding area 1150 in the length direction (i.e., the third direction Z) accounts for more than 50% of the length of the second adapter 1127 in that direction. It can be seen that the welding area between the second tab 1126 and the second adapter 1127 can be greatly increased.

[0170] During the welding process between the second tab 1126 and the second adapter 1127, the vibration direction of the welding head is set along the third direction Z (or the second direction Y) (i.e., transverse welding method) to ensure that the welding area can extend fully in the third direction Z, so that the fourth length L4 reaches 50%-100% of the third length L3. The welding method in this example is different from the longitudinal welding in related technologies, which can effectively increase the welding area and reduce the risk of incomplete welding.

[0171] In this embodiment, a second tab 1126 is matched and connected to a second adapter 1127, so that the second tab 1126 and the second adapter 1127 can be welded laterally, forming a third welding area 1150 with a length exceeding 50% of the length of the second adapter 1127, thereby increasing the effective welding area and improving the current carrying capacity between the second tab 1126 and the second adapter 1127.

[0172] In some embodiments, refer to Figure 11 As shown, along the first direction X, the second electrode terminal 1128 is disposed at one end of the electrode assembly 1122 that is provided with the second tab 1126. Along the first direction X, the side of the second electrode terminal 1128 facing each electrode assembly 1122 is provided with a second groove structure 11281 corresponding to each second adapter 1127. The second adapter 1127 is at least partially accommodated in the second groove structure 11281.

[0173] Specifically, the second electrode terminal 1128 and each electrode assembly 1122 (i.e., the second electrode tab 1126) are arranged opposite to each other in the first direction X, that is, the first direction X is the relative orientation direction of the two (such as the vertical direction).

[0174] Along the first direction X, one end of the second electrode terminal 1128 facing each electrode assembly 1122 (i.e., the end of the second electrode terminal 1128 extending into the receiving cavity 11211) is provided with a second groove structure 11281 corresponding to each second adapter 1127. The shape and size of the second groove structure 11281 are adapted to the shape and size of the connecting portion of the second adapter 1127, ensuring that the second adapter 1127 can be at least partially accommodated within the second groove structure 11281. The depth of the second groove structure 11281 can be set according to assembly requirements, as long as it can achieve partial accommodation of the second adapter 1127. For example, if the connecting portion of the second adapter 1127 is sheet-like with a thickness of H3, and the thickness of the second groove structure 11281 in the first direction X is H4, then H3 can be greater than or equal to H4, or H3 can be less than H4.

[0175] It should be noted that the groove depth of the second groove structure 11281 is along the first direction X, and the groove wall of the second groove structure 11281 facing the second adapter 1127 should be provided through, so that the second adapter 1127 can extend from inside the second groove structure 11281 through the through groove wall to the outside of the second groove structure 11281 and then connect with the second electrode 1126.

[0176] One end of the second adapter 1127 is welded and fixed to the second tab 1126, and the other end is at least partially embedded in the second groove structure 11281 of the second electrode terminal 1128. Then, the second adapter 1127 is fixedly connected to the inner wall or bottom of the second groove structure 11281 by laser welding to achieve electrical connection between the two. The second groove structure 11281 plays a positioning and limiting role for the second adapter 1127, reducing the risk of the second adapter 1127 shifting during welding. In addition, in the first direction X, the second adapter 1127 is accommodated in the second groove structure 11281, thereby saving more space in the first direction X. The electrode portion (or the wound body or the stacked body) of the electrode assembly 1122 can have a greater height, which is beneficial to improving the energy density of the battery cell 1120.

[0177] Regarding the design of the second groove structure 11281 in this application, the second groove structure 11281 serves to position the second adapter 1127. During the welding and assembly process, it can quickly achieve precise alignment between the second adapter 1127 and the second electrode terminal 1128, reducing welding defects caused by alignment deviations. In addition, the second adapter 1127 is partially housed within the second groove structure 11281, increasing the contact area between the two. Furthermore, the second groove structure 11281 can restrict the displacement of the second adapter 1127 in the horizontal direction (perpendicular to the first direction X), improving the stability of the connection structure and reducing the problem of loosening of the connection caused by vibration and other factors during the operation of the battery cell 1120.

[0178] Furthermore, the second adapter 1127 is partially housed within the second recess structure 11281 of the second electrode terminal 1128. Compared to a planar connection where the two components are completely fitted together, this embedded structure effectively reduces the space occupied by both components in the first direction X. With the volume of the housing 1121 of the battery cell 1120 remaining fixed, the saved internal space can be used to accommodate a larger electrode assembly 1122 or increase the capacity of the winding body of the electrode assembly 1122, thereby improving the energy density of the battery cell 1120.

[0179] Furthermore, the second groove structure 11281 makes the contact between the second adapter 1127 and the second electrode terminal 1128 tighter and reduces the contact resistance. In addition, the embedded connection method makes the current conduction path more regular, reduces the local heat generation problem caused by poor contact, enhances the smoothness of current conduction, and further ensures the overcurrent performance and operational stability of the battery cell 1120.

[0180] In this embodiment, by providing the second groove structure 11281, the second adapter 1127 can be limited and positioned, which is beneficial to improving space utilization and increasing the energy density of the battery cell 1120.

[0181] In some embodiments, refer to Figure 8 As shown, along the first direction X, the second electrode terminal 1128 is disposed towards the end of the electrode assembly 1122 that is provided with the second tab 1126. Multiple electrode assemblies 1122 are stacked sequentially in the second direction Y, which is perpendicular to the first direction X. Each second tab 1126 is welded to each second adapter 1127 at a third position 1161 to form a third welding area 1150. The second electrode terminal 1128 is welded to each second adapter 1127 at a fourth position 1162 to form a fourth welding area 1160. In the second direction Y, the extended portion of the second electrode terminal 1128 connected to the second adapter 1127 extends beyond the third position 1161, so that the third welding area 1150 and the fourth welding area 1160 have at least an overlapping portion.

[0182] Specifically, the setting of the first direction X and the second direction Y, the positional relationship between the second electrode terminal 1128 and the electrode assembly 1122, and the arrangement of the multiple electrode assemblies 1122 can be referred to the above example, and will not be repeated here.

[0183] Each second electrode tab 1126 is welded to each second adapter 1127 at a third position 1161 to form a third welding area 1150, which is an ultrasonic welding area; the second electrode terminal 1128 is welded to each second adapter 1127 at a fourth position 1162 to form a fourth welding area 1160, which is a laser welding area.

[0184] In the second direction Y, the extended portion of the second electrode terminal 1128 connected to the second adapter 1127 extends beyond the third position 1161, so that the third welding area 1150 and the fourth welding area 1160 have at least an overlapping portion, that is, the projection area of ​​the third welding area 1150 in the first direction X and the projection area of ​​the fourth welding area 1160 in the first direction X have an overlapping portion, that is, the laser-welded fourth welding area 1160 covers part or all of the ultrasonic-welded third welding area 1150, and there is an overlapping area between the two.

[0185] Since the extended portion of the second electrode terminal 1128 connected to the second adapter 1127 extends beyond the third position 1161, it is known that the second electrode terminal 1128 has a larger extension length. Part of the current flow path on the second adapter 1127 is transferred to the second electrode terminal 1128. It is known that the second electrode terminal 1128 has better current carrying capacity. Therefore, this design can improve the current carrying capacity and effect between the electrode assembly 1122 and the second electrode terminal 1128.

[0186] Furthermore, the overlap between the third welding area 1150 and the fourth welding area 1160 allows laser welding to further strengthen the connection strength of ultrasonic welding. The coverage of the ultrasonic welding area by laser welding further enhances the connection's firmness. Moreover, the overlap between the third welding area 1150 and the fourth welding area 1160 creates a double-reinforced structure for the connection of the second tab 1126, the second adapter 1127, and the second electrode terminal 1128. This not only improves the mechanical connection strength but also increases the conductive contact area, reduces contact resistance, and ensures the reliability of current conduction.

[0187] In some embodiments, refer to Figure 9 As shown, the extended portion of the second electrode terminal 1128 connected to the second adapter 1127 avoids the third position 1161, so that the third welding area 1150 is spaced apart from the fourth welding area 1160.

[0188] Specifically, in the second direction Y, the extended portion of the second electrode terminal 1128 connected to the second adapter 1127 avoids the third position 1161, so that the third welding area 1150 and the fourth welding area 1160 are spaced apart. That is, there is a gap between the fourth welding area 1160 of laser welding and the third welding area 1150 of ultrasonic welding, and the two do not overlap.

[0189] Reliable electrical connections can be achieved through ultrasonic welding of the second electrode tab 1126 and the second adapter 1127, and laser welding of the second adapter 1127 and the second electrode terminal 1128. The two welding areas are set up independently, reducing the risk of damage to the ultrasonic welding area caused by the high temperature of laser welding.

[0190] This embodiment provides two positioning schemes for the welding areas, which can be selected according to the actual production process, material characteristics, and performance requirements. For scenarios where the ultrasonic welding area is sensitive to high temperatures, the avoidance method shown in this example can be selected. This avoidance setting reduces the risk of damage caused by the high temperatures of laser welding, ensuring welding quality and improving the flexibility and adaptability of product design. The spacing between the two welding areas reduces the risk of mutual interference between different welding processes, and each welding area can maintain its independent connection performance, thus ensuring the reliability of the overall connection.

[0191] In this embodiment, the overlapping of the third welding area 1150 and the fourth welding area 1160 can improve the reliability of the connection. The alternating arrangement of the third welding area 1150 and the fourth welding area 1160 is suitable for situations sensitive to high-temperature laser welding and can reduce mutual interference between different welding methods.

[0192] In some embodiments, refer to Figure 10As shown, along the first direction X, the second electrode terminal 1128 is disposed towards the end of the electrode assembly 1122 that is provided with the second tab 1126. Multiple electrode assemblies 1122 are stacked sequentially in the second direction Y, which is perpendicular to the first direction X. The second electrode terminal 1128 is welded to each of the second adapters 1127 at the fourth position 1162 to form a fourth welding area 1160. The fourth welding area 1160 spans between any two adjacent second adapters 1127.

[0193] Specifically, the settings of the first direction X and the second direction Y, the positional relationship between the second electrode terminal 1128 and the electrode assembly 1122, and the arrangement of the multiple electrode assemblies 1122 can be referred to the above example, and will not be repeated here.

[0194] The second electrode terminal 1128 is welded to each of the second adapters 1127 at the fourth position 1162 to form a fourth welding area 1160, which is a laser welding area. In the second direction Y, the fourth welding area 1160 spans between any two adjacent second adapters 1127. That is, a single fourth welding area 1160 simultaneously covers the ends of two adjacent second adapters 1127 and is welded and fixed to the second electrode terminal 1128, achieving electrical connection between two adjacent second adapters 1127 and the second electrode terminal 1128 through the same laser welding area.

[0195] Two adjacent second adapters 1127 are spaced apart in the second direction Y, and the distance between them can be less than the length of the fourth welding area 1160 (along the second direction Y). During laser welding, the weld mark spans the connection surface between the ends of two adjacent second adapters 1127 and the second electrode terminal 1128, so that the two adjacent second adapters 1127 simultaneously form a reliable electrical connection with the second electrode terminal 1128 through the spanning fourth welding area 1160. In addition, the two adjacent second adapters 1127 are also indirectly electrically connected to each other through the fourth welding area 1160.

[0196] In this case, multiple fourth welding areas 1160 can be provided, and multiple fourth welding areas 1160 are arranged sequentially at intervals in the third direction Z, so that the second adapter 1127 and the second electrode terminal 1128 have a larger welding area in the length direction (i.e., the third direction Z) to improve the firmness between the second adapter 1127 and the second electrode terminal 1128.

[0197] In this embodiment, a single fourth welding area 1160 spans two adjacent second adapters 1127, making the two adjacent second adapters 1127 and the second electrode terminal 1128 form an integral connection structure. This not only improves the connection strength between each second adapter 1127 and the second electrode terminal 1128, but also enhances the cooperative stability between adjacent second adapters 1127, reducing the overall performance degradation caused by loose connection of a single second adapter 1127.

[0198] Furthermore, the transverse fourth welding area 1160 allows for partial current diversion between the two adjacent second adapters 1127, reducing the problem of excessive current concentration in a single second adapter 1127. Simultaneously, the integral welding area ensures a more balanced path for current conduction from the two second adapters 1127 to the second electrode terminal 1128, reducing local impedance differences during current conduction, improving the uniformity of current conduction, reducing the risk of excessive localized heating, and ensuring the operational stability of the battery cell 1120.

[0199] Furthermore, in this embodiment, a single fourth welding area 1160 can simultaneously complete the welding of two adjacent second adapters 1127, reducing the number of laser welding operations. This reduction in welding operations not only lowers process operation time but also reduces energy and material consumption during the welding process, significantly improving production efficiency and lowering industrial production costs.

[0200] In this embodiment, the fourth welding area 1160 spans between two adjacent second adapters 1127, which can enhance the cooperative stability between adjacent second adapters 1127, improve the current uniformity, and ensure the working stability of the battery cell 1120.

[0201] In some embodiments, refer to Figure 11 As shown, there are two electrode assemblies 1122. Along the first direction X, the second electrode terminal 1128 is disposed at the end of the electrode assembly 1122 that is provided with the second tab 1126. In the second direction Y, the second electrode terminal 1128 is provided with two protruding second outer edges 11282, and the two second outer edges 11282 are respectively electrically connected to the two second adapters 1127. The first direction X is perpendicular to the second direction Y.

[0202] Specifically, there are two electrode assemblies 1122, both of which are housed in the receiving cavity 11211 of the housing 1121 and are stacked sequentially along the second direction Y (perpendicular to the first direction X) (see the example above). Each electrode assembly 1122 is provided with a second tab 1126 for connecting to the corresponding second adapter 1127.

[0203] The second electrode terminal 1128 is disposed opposite to the electrode assembly 1122 in the first direction X. In the second direction Y, the second electrode terminal 1128 has two protruding second outer edges 11282. For example, the second electrode terminal 1128 includes a second column portion located in the middle and second outer edges 11282 connected to both sides of the second column portion. The two second outer edges 11282 are respectively stacked and welded to the two second adapters 1127. The second outer edge 11282 is a protruding structure formed by the second column portion extending in the second direction Y, and the extension direction of the second outer edge 11282 is consistent with the stacking direction of the two electrode assemblies 1122.

[0204] One end of each of the two second adapters 1127 is ultrasonically welded to the second tabs 1126 of the two electrode assemblies 1122. Then, the other ends of the two second adapters 1127 are laser welded to the two second outer edges 11282 of the second electrode terminal 1128, forming two independent current conduction paths of "electrode assembly 1122 - second adapter 1127 - second outer edge 11282 - second electrode terminal 1128 body", ultimately realizing the parallel electrical connection between the two electrode assemblies 1122 and the external circuit.

[0205] In this example, for the configuration of the two electrode assemblies 1122, the two second outer edges 11282 of the second electrode terminal 1128 protrude outward along the second direction Y, which can accurately adapt to the arrangement position of the two second adapters 1127, reducing the internal space occupation problem caused by the excessive size of the second column portion of the second electrode terminal 1128. The protruding second outer edges 11282 allow the connection position of the second adapter 1127 and the second electrode terminal 1128 to be closer to the second tab 1126 of the electrode assembly 1122, shortening the current conduction path and reducing the conduction impedance.

[0206] Furthermore, the two second outer edges 11282 are respectively connected to the two second adapters 1127 in a one-to-one correspondence, making the structures of the two current conduction paths completely symmetrical. This symmetrical structure ensures uniform current distribution between the two electrode assemblies 1122, reducing current imbalance caused by path differences and guaranteeing the operational stability of the battery cell 1120. Additionally, the protruding structure of the second outer edges 11282 increases the contact area with the second adapters 1127, improving the reliability of the welded connection and reducing the risk of loosening.

[0207] Of course, the electrode assembly 1122 can also be provided in three, four, etc. In general, an even number of electrode assemblies 1122 are more commonly used to form a symmetrical arrangement, which is conducive to achieving uniformity of flow conduction.

[0208] Furthermore, the use of two electrode assemblies 1122 also facilitates the ultrasonic welding of the second electrode tab 1126 and the second adapter 1127 by arranging the two electrode assemblies 1122 back to back, allowing simultaneous welding on two fluxes, thereby improving welding efficiency.

[0209] In this embodiment, the two electrode assemblies 1122 are arranged in a configuration that allows the two electrode assemblies 1122 to be symmetrically arranged on both sides of the second electrode terminal 1128. The connection between the second adapter 1127 and the second electrode terminal 1128 is also more reliable, which helps to improve the stability of the entire battery cell 1120.

[0210] In some embodiments, refer to Figure 12 As shown, the multiple second adapters in the multiple electrode assemblies 1122 are an integral structure.

[0211] Specifically, the second adapter 1127 is a one-piece molded structure. This one-piece structure is adapted to the second tabs 1126 of multiple electrode assemblies 1122. That is, a single one-piece second adapter 1127 is connected to the second tabs 1126 of all electrode assemblies 1122. The one-piece second adapter 1127 can be manufactured by one-piece molding processes such as stamping and casting. Its overall shape needs to adapt to the arrangement of multiple second tabs 1126 (such as extending along the second direction Y to form a strip structure). Adaptive connecting parts are formed at the positions corresponding to each second tab 1126 to ensure stable fit with each second tab 1126.

[0212] The second electrode terminal 1128 is disposed opposite to each electrode assembly 1122 in the first direction X, and the multiple electrode assemblies 1122 are stacked sequentially in the second direction Y, which is perpendicular to the first direction X. The structure of the second electrode terminal 1128 is adapted to the shape of the integrated second adapter 1127, and the connection surface between the second electrode terminal 1128 and the second adapter 1127 must cover the connection area of ​​the integrated second adapter 1127 to ensure a reliable electrical connection. The positions of the multiple second tabs 1126 are arranged sequentially along the second direction Y, corresponding one-to-one with the connection portion of the integrated second adapter 1127, without mutual interference.

[0213] The second tabs 1126 of multiple electrode assemblies 1122 are fixedly connected to the corresponding connecting parts of the integrated second adapter 1127 by ultrasonic welding. During the welding process, it is ensured that the welding surfaces of each second tab 1126 and the corresponding connecting parts are in full contact to reduce the probability of local cold welding. The end of the integrated second adapter 1127 is fixedly connected to the second electrode terminal 1128 by laser welding, thus forming a centralized current conduction path of "multiple electrode assemblies 1122 - integrated second adapter 1127 - second electrode terminal 1128", which together with the path of "multiple electrode assemblies 1122 - multiple independent first adapters 1123 - first electrode terminal 1124" constitutes the complete current loop of the battery cell 1120.

[0214] The integrated second adapter 1127 of this embodiment enables "multi-point fixation with a single welding operation." When welding to the second tab 1126, ultrasonic welding of all second tabs 1126 to the second adapter 1127 can be completed in a single positioning operation; when welding to the second electrode terminal 1128, only one laser welding operation is required for overall fixation, significantly reducing the number of welding operations. This reduction in welding operations not only shortens assembly time but also reduces the accumulation of positioning errors, improves the consistency of mass production, and significantly reduces process complexity and production time.

[0215] As can be seen, in this application, the first electrode tab 1125 of the multiple electrode assemblies 1122 can be connected to the first electrode terminal 1124 through a separate first adapter 1123, and the second electrode tab 1126 of the multiple electrode assemblies 1122 can also be connected to the second electrode terminal 1128 through a separate second adapter 1127. Alternatively, the second electrode tab 1126 of the multiple electrode assemblies 1122 can also be connected to the second electrode terminal 1128 through an integrated adapter (multiple second adapters 1127 of an integrated structure), making the connection combination of the electrode tabs and the electrode terminals through the adapters more flexible.

[0216] In this embodiment, the multiple second adapters adopt an integrated structure, which can reduce the number of welding operations, improve welding efficiency, and form a reasonable combination with the multiple separate first adapters 1123, thereby increasing the diversity of the battery cell 1120 structure and improving manufacturing flexibility.

[0217] In one embodiment, reference Figure 3 and Figure 5 As shown, the outer casing 1121 includes a casing body and a top cover 1180. A receiving groove is formed inside the casing body, and the top cover 1180 is connected to the casing body and covers the opening of the receiving groove.

[0218] The top cover 1180 can be made of a metal material (such as aluminum alloy) in a plate-like structure, adapted to the top opening shape of the main body (aluminum shell) (square top cover 1180 corresponds to square shell battery), and is provided with mounting holes for installing the first electrode terminal 1124 and the second electrode terminal 1128, as well as reserved structures for liquid injection and explosion protection (such as liquid injection hole and explosion protection valve mounting position).

[0219] The top cover 1180 serves as the sealing end cover of the outer shell 1121, and together with the aluminum shell, it forms a closed accommodating cavity 11211. The top cover 1180 provides an installation reference for components such as electrode terminals, terminal plastic 1190, and sealing ring 1192. It also bears the structural stress on the top of the battery cell 1120, ensuring the overall structural strength.

[0220] The electrode post plastic 1190 is made of engineering plastics with excellent insulation properties (such as PP and PPS), and has a ring or sleeve-shaped structure. Its inner diameter is adapted to the outer diameter of the first electrode terminal 1124 or the second electrode terminal 1128, and its outer diameter is adapted to the mounting hole size of the top cover 1180. It has a stepped structure to avoid the electrode post welding block 1191 and a sealing groove to cooperate with the sealing ring 1192.

[0221] The electrode post plastic 1190 is used to achieve electrical insulation between the electrode terminal and the top cover 1180, reducing the risk of short circuit caused by direct contact between the electrode terminal and the metal top cover 1180; the electrode post plastic 1190 provides radial positioning for the electrode terminal, ensuring the coaxiality of the electrode terminal after installation; and enhances the sealing performance between the electrode terminal and the top cover 1180 by cooperating with the sealing ring 1192.

[0222] The electrode welding block 1191 is made of a block or ring structure of a metal material with excellent conductivity (such as copper or aluminum, matching the material of the electrode terminal), and may also have a connecting surface (such as a flat surface or a threaded surface) that mates with the electrode terminal (such as a stepped electrode).

[0223] The electrode welding block 1191 is used to limit and fix the electrode terminals during welding. By fixing it to the electrode terminals, it strengthens the installation strength of the electrode terminals and reduces the risk of the electrode terminals loosening due to welding stress or vibration.

[0224] The sealing ring 1192 is an annular structure made of an electrolyte-resistant and high-temperature-resistant elastic material (such as fluororubber or EPDM). Its cross-section is circular or rectangular, and its dimensions are adapted to the sealing groove of the electrode post plastic 1190 and the inner wall dimensions of the mounting hole of the top cover 1180. The sealing ring 1192 is used to achieve a dynamic or static seal between the electrode terminals and the top cover 1180, preventing electrolyte leakage from the accommodating cavity 11211, while also preventing external air and moisture from entering the accommodating cavity 11211, thus ensuring the sealing reliability and electrochemical performance stability of the battery cell 1120.

[0225] The lower plastic 1170 is made of insulating plastic (such as PP) in a frame or gasket structure, adapted to the bottom shape of the electrode assembly 1122 (bare cell) and the internal bottom dimensions of the housing 1121, and is provided with a limiting groove for positioning the electrode assembly 1122 and a notch for avoiding the electrode tab.

[0226] The lower plastic 1170 is used to achieve electrical insulation between the electrode assembly 1122 and the top cover 1180, reducing the risk of short circuit caused by direct contact between the electrode assembly 1122 and the metal casing 1121; it provides positioning for multiple stacked electrode assemblies 1122, ensuring that the electrode assemblies 1122 are arranged neatly in the accommodating cavity 11211; and it buffers the vibration of the electrode assembly 1122 during the operation of the battery cell 1120, reducing stress damage to the tabs.

[0227] In one specific embodiment, the battery cell 1120 includes a housing 1121, a first electrode terminal 1124, and an electrode assembly 1122. The housing 1121 has a receiving cavity 11211. The first electrode terminal 1124 is connected to the housing 1121 and is at least partially exposed on the outer surface of the housing 1121. Multiple electrode assemblies 1122 are provided and are all housed within the receiving cavity 11211. Each electrode assembly 1122 includes a first tab 1125. Multiple first adapters 1123 are provided, and each first adapter 1123 is matched one-to-one with a multiple first tab 1125. The first tab 1125 of each electrode assembly 1122 is connected to the first electrode terminal 1124 through the corresponding first adapter 1123. The electrodes are electrically connected; the first electrode terminal 1124 and each electrode assembly 1122 are arranged opposite to each other in the first direction X, and the multiple electrode assemblies 1122 are stacked sequentially in the second direction Y; in the second direction Y, multiple first adapters 1123 are arranged sequentially, and any two adjacent first adapters 1123 are spaced apart in the second direction Y; in the third direction Z, the first adapter 1123 has a first length L1; the first tab 1125 is welded to the first adapter 1123 to form a first welding area 1130, and the first welding area 1130 has a second length L2 in the third direction Z, the second length L2 being 50%-100% of the first length L1; the first direction X, the second direction Y, and the third direction Z are mutually connected. Vertically; the first electrode terminal 1124 and each electrode assembly 1122 are arranged opposite to each other in the first direction X. Along the first direction X, the end of the first electrode terminal 1124 facing each electrode assembly 1122 is provided with a first groove structure 11241 corresponding to each first adapter 1123. The first adapter 1123 is at least partially accommodated in the first groove structure 11241. Each first tab 1125 is welded to each first adapter 1123 at a first position 1141 to form a first welding area 1130. The first electrode terminal 1124 is welded to each first adapter 1123 at a second position 1142 to form a second welding area 1140. In the second direction Y, the first electrode terminal 1124 and the first adapter 1122 are arranged opposite to each other in the first direction X. The extended portion connected to the connector 1123 extends beyond the first position 1141, so that the first welding area 1130 and the second welding area 1140 have at least an overlapping portion; or, the extended portion of the first electrode terminal 1124 connected to the first adapter 1123 avoids the first position 1141, so that the first welding area 1130 and the second welding area 1140 are spaced apart; two electrode assemblies 1122 are provided, the first electrode terminal 1124 and the electrode assembly 1122 are arranged opposite to each other in the first direction X, and in the second direction Y, the first electrode terminal 1124 is provided with two protruding first outer edges 11242, and the two first outer edges 11242 are respectively electrically connected to the two first adapters 1123 one by one;The battery cell 1120 also includes a second electrode terminal 1128 and a second adapter 1127. The second electrode terminal 1128 is connected to the housing 1121 and is at least partially exposed on the outer surface of the housing 1121. The second electrode terminal 1128 is arranged at intervals from the first electrode terminal 1124. Each electrode assembly 1122 also includes a second tab 1126. The second tabs 1126 of each electrode assembly 1122 are electrically connected to the second electrode terminal 1128 through the second adapter 1127. The second electrode terminal 1128 and each electrode assembly 1122 are arranged opposite to each other in the first direction X. In the second direction Y, a plurality of second adapters 1127 are arranged sequentially, and any two adjacent second adapters 1127 are arranged at intervals in the second direction Y. In the third direction Z, the second adapter 1127 has a third length L3. The second tab 1126 and the second electrode terminal 1128 are connected to the first electrode terminal 1128. The adapter 1127 is welded to form a third welding area 1150. The third welding area 1150 has a fourth length L4 in the third direction Z, and the fourth length L4 is 50%-100% of the third length L3. The second electrode terminal 1128 is disposed opposite to each electrode assembly 1122 in the first direction X. Along the first direction X, the side of the second electrode terminal 1128 facing each electrode assembly 1122 is provided with a second groove structure 11281 corresponding to each second adapter 1127. The second adapter 1127 is at least partially accommodated in the second groove structure 11281. The second electrode terminal 1128 is welded to each second adapter 1127 at a fourth position 1162 to form a fourth welding area 1160. The fourth welding area 1160 spans between any two adjacent second adapters 1127.

[0228] According to some embodiments of this application, refer to Figure 2 As shown, this application also provides a battery device 1100, which includes battery cells 1120 as described in any of the above claims. The battery device 1100 may include one or more battery cell 1120 assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells 1120, which are connected in series, parallel, or mixed connections via a busbar. The battery device 1100 may be a battery pack, which generally includes a housing 1110 and one or more battery cell 1120 assemblies housed within the housing 1110.

[0229] In some embodiments, the housing 1110 may include a first portion 1111 and a second portion 1112, which overlap each other, defining a space for accommodating the battery cell 1120. The second portion 1112 may be a hollow structure with one open end, while the first portion 1111 may be a plate-like structure, covering the open side of the second portion 1112 so that the first portion 1111 and the second portion 1112 together define an accommodating space 1113. Alternatively, both the first portion 1111 and the second portion 1112 may be hollow structures with one open side, with the open side of the first portion 1111 covering the open side of the second portion 1112. Of course, the housing 1110 formed by the first portion 1111 and the second portion 1112 can be of various shapes, such as a cylinder or a cuboid.

[0230] For details, please refer to the description of the above embodiments, which will not be repeated here.

[0231] According to some embodiments of this application, refer to Figure 1 As shown, this application also provides an electrical device, which includes the battery cell 1120 in the above embodiments or the battery device 1100 in the above embodiments. The battery cell 1120 and the battery device 1100 are used to store or provide electrical energy.

[0232] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use battery cells 1120, such as mobile phones, portable devices, laptops, electric vehicles, electric toys, power tools, vehicles 1000, ships and spacecraft, etc. For example, spacecraft include airplanes, rockets, space shuttles and spacecraft.

[0233] The examples of electrical devices in this application are based on the examples of the battery cell 1120 and battery device 1100 described above. The examples of electrical devices include all the technical effects of the examples of the battery cell 1120 and battery device 1100 described above, and will not be repeated here.

[0234] According to some embodiments of this application, this application also provides a method for preparing a battery cell 1120. The method is used to prepare the battery cell 1120 in any of the above embodiments. The method includes the following steps: Step S01, prefabricating a shell 1121, a first electrode terminal 1124, a plurality of electrode assemblies 1122 and a plurality of first adapters 1123, each electrode assembly 1122 having a first tab 1125; Step S02, each first tab 1125 is welded to each first adapter 1123 in a one-to-one correspondence; Step S03, the plurality of first adapters 1123 are all welded to the first electrode terminal 1124 to form an integral electrode assembly; Step S04, the electrode assembly is assembled with the shell 1121.

[0235] Specifically, in step S01, multiple electrode components 1122 are prefabricated. There are two main methods for preparing the electrode components 1122 in the battery cell 1120: winding and stacking. The winding method uses a winding process to stack the positive electrode sheet, negative electrode sheet, and separator into a cylindrical or flat core. The specific steps include: first, placing the positive electrode sheet, negative electrode sheet, and separator in sequence, and then tightly winding them using a winding machine to form the electrode component 1122. This method has a high degree of automation and fast production efficiency, and is suitable for cylindrical or square batteries. However, during the winding process, the tension and alignment accuracy must be strictly controlled to reduce internal damage or unevenness. The stacking method involves alternately stacking pre-cut positive electrode sheets, negative electrode sheets, and separators. Specific steps include: first, sequentially cutting the positive electrode sheets, separator, and negative electrode sheets to specified dimensions; then, precisely stacking them into a battery cell using a robotic arm or automated equipment. This method results in tighter internal contact and lower internal resistance for the electrode assembly 1122, making it suitable for high-rate discharge scenarios. However, the process is complex, production speed is relatively slow, and it requires extremely high precision in die-cutting and stacking alignment. Both methods require ultra-clean environments to prevent dust contamination from affecting battery performance, and pre-treatment of the electrode sheets, such as cold pressing and die-cutting, is performed before fabrication to ensure coating uniformity and dimensional accuracy.

[0236] The tabs (including the first tab 1125 and the second tab 1126) are conductors cut out from the edge of the electrode by laser cutting or mechanical punching. The tabs are welded to the adapter (for example, the first tab 1125 is welded to the first adapter 1123) to achieve current conduction.

[0237] The first adapter 1123 can be formed by stamping, shearing or other methods. The size of the first adapter 1123 should be adapted to the size and shape of the connection position of the first electrode 1125 so that the first adapter 1123 and the first electrode 1125 have a large overlap and fit area, which provides a basis for forming a large welding area in the future. The first adapter 1123 is made of a metal with excellent conductivity (such as copper, aluminum or their alloys). The first adapter 1123 is the adapter piece on the positive side, and the first tab 1125 should be made of aluminum, while the negative side should be made of copper, in order to reduce the risk of electrochemical corrosion caused by contact between dissimilar metals. The size should be adapted to the welding requirements of the first tab 1125 (such as the adapter piece length 10-20mm, width 5-8mm, thickness 0.2-0.5mm). During the prefabrication process, the flatness (flatness ≤0.1mm / m) and dimensional tolerance (±0.05mm) of the adapter piece should be controlled by precision stamping process to reduce the impact of deformation or dimensional deviation of the first adapter 1123 on the subsequent welding accuracy.

[0238] In addition, the first electrode terminal 1124 and the outer shell 1121 can be prefabricated simultaneously. The outer shell 1121 can adopt a plate assembly structure or a roll forming structure, etc. The structure of the first electrode terminal 1124 needs to be adapted to the welding arrangement requirements of multiple first adapters 1123 (such as preparing the first groove structure 11241 and the second groove structure 11281). The material of the first electrode terminal 1124 needs to match the first adapter 1123 (e.g., aluminum adapter piece corresponds to aluminum terminal, copper adapter piece corresponds to copper terminal), and the surface needs to be polished (surface roughness Ra≤0.8μm) to reduce contact resistance.

[0239] In step S02, each first tab 1125 is welded to each first adapter 1123.

[0240] Each first tab 1125 is welded to each first adapter 1123 in a one-to-one correspondence. The welding process adopts ultrasonic welding. During the welding process, a special fixture is used to position the electrode assembly 1122 and the first adapter 1123 to ensure the alignment accuracy of the first tab 1125 and the adapter piece, and to ensure that each first adapter 1123 is connected to only one corresponding first tab 1125, thereby reducing the risk of short circuit caused by cross welding.

[0241] During the welding process, a welding device 1193 can be used to weld a set of first tabs 1125 and first adapters 1123; alternatively, two welding devices 1193 can be arranged opposite each other, so that the two electrode assemblies 1122 can be set back to back. The first tabs 1125 and first adapters 1123 in one electrode assembly 1122 are set close to one welding device 1193, and the first tabs 1125 and first adapters 1123 in the other electrode assembly 1122 are set close to another welding device, forming a back-to-back setting and simultaneous welding method to improve welding efficiency.

[0242] Based on the split structure of multiple first adapters 1123, the welding equipment 1193 can perform transverse welding when welding the first tab 1125 and the first adapter 1123, thereby increasing the welding area between the first tab 1125 and the first adapter 1123.

[0243] In step S03, multiple first adapters 1123 are welded to the first electrode terminal 1124 to form an integral electrode assembly.

[0244] Specifically, multiple first adapters 1123 are welded to the first electrode terminal 1124, so that multiple electrode assemblies 1122 are electrically connected to the first electrode terminal 1124 through their respective first adapters 1123, ultimately forming an integrated electrode assembly. Laser welding can be used in this step, and the welding method can be selected according to the structure of the first electrode terminal 1124, including single-point welding, transverse welding, or recessed welding (when the first electrode terminal 1124 has a first recessed structure 11241). The welding parameters must match the materials of the first adapters 1123 and the first electrode terminal 1124 to ensure welding strength and electrical conductivity reliability. This step integrates the dispersed electrode assemblies 1122 into a single integrated assembly, facilitating subsequent precise assembly with the outer casing 1121.

[0245] It should be noted that in step S02, the welding of the first electrode tab 1125 and the first adapter 1123 should be performed at the first station, which is an ultrasonic welding station. In step S03, the welding between the first adapter 1123 and the first electrode terminal 1124 should be performed at the second station, which is a laser welding station. It can be seen that there is a workpiece transfer process between steps S02 and S03. During the process of moving the electrode assembly 1122 connected to the first adapter 1123 from the first station to the second station by mechanical transfer tools (such as a robot), since one first adapter 1123 is connected to one electrode assembly 1122, there is no risk of pulling or cracking between the two electrode assemblies 1122 and the shared adapter plate during the transfer process, which reduces the risk of damaging the electrode assembly 1122 during the transfer process.

[0246] In step S04, the electrode assembly is assembled with the housing 1121.

[0247] Specifically, the integrated electrode assembly is inserted into the receiving cavity 11211 of the housing 1121, completing the assembly of the electrode assembly and the housing 1121. During assembly, it is necessary to ensure that the position of the electrode assembly conforms to the internal spatial layout requirements of the housing 1121 to reduce the risk of interference with the inner wall of the housing 1121. After assembly, the housing is sealed (e.g., the top cover 1180 is welded to seal) to ensure the airtightness of the receiving cavity 11211 and reduce the impact of the external environment on the internal electrode assembly 1122.

[0248] In some embodiments, the battery cell 1120 also includes an electrolyte that acts as a conductor of ions between the positive and negative electrodes.

[0249] In the preparation process of the battery cell 1120, the top cover 1180 is pre-installed and has a reserved liquid injection hole. After vacuum baking to remove water, liquid is injected, allowed to stand and soak, the liquid injection hole is sealed, and formation or capacity testing is performed. The top cover 1180 is installed first to fix the electrode assembly and form a semi-sealed cavity. The liquid injection hole is left to be sealed last to reduce the risk of moisture absorption and side reactions after prolonged exposure to open space after liquid injection.

[0250] This application does not impose specific restrictions on the type of electrolyte; it can be selected according to requirements. The electrolyte can be liquid, gel-like, or solid. Liquid electrolytes include electrolyte salts and solvents.

[0251] In some embodiments, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0252] In some embodiments, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0253] In some embodiments, the electrolyte may optionally include additives. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain properties of the battery cell 1120, such as additives that improve the overcharge / fast charge performance of the battery cell 1120, additives that improve the high-temperature performance of the battery cell 1120, additives that improve the low-temperature performance of the battery cell 1120, etc.

[0254] The gel electrolyte includes a polymer as a backbone network and can be used in conjunction with an ionic liquid-lithium salt.

[0255] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0256] As an example, the polymers of polymeric solid electrolytes may include polyethers (polyoxyethylene), polysiloxanes, polycarbonates, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids, cellulose, etc.

[0257] As an example, inorganic solid electrolytes can be one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium germanium phosphorus sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0258] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0259] In this embodiment, because the adapter adopts a split structure of multiple first adapters 1123, each first tab 1125 can be independently welded to each first adapter 1123. This makes the welding method more flexible and allows for further improvement of the welding area between the first tab 1125 and the first adapter 1123 through lateral welding, thereby enhancing the current-carrying capacity between them. Furthermore, this manufacturing method employs a "step-by-step welding combined with overall assembly" approach. First, the dispersed electrode components 1122 are integrated into a single assembly via the first adapter 1123 and the first electrode terminal 1124, and then the entire assembly is encapsulated. Compared to the traditional process of "encapsulating each electrode component 1122 individually and then welding," overall assembly reduces the number of encapsulation steps and internal welding operations, lessens the limitations imposed by the confined space within the housing on welding operations, significantly improves assembly efficiency, and is suitable for large-scale mass production.

[0260] In some embodiments, refer to Figure 6 and Figure 7 As shown, the first electrode 1125 and the first adapter 1123 are ultrasonically welded, and the ultrasonic welding method is transverse welding.

[0261] Specifically, transverse welding aligns the direction of ultrasonic vibration with the extension direction of the welding surface, its advantage stemming from the matching of energy distribution with the welding surface. From the perspective of the energy transfer principle of ultrasonic welding, the high-frequency vibration of the welding head (e.g., 20-40kHz) causes plastic flow in the metal at the contact interface, forming a metallurgical bond. When the vibration direction is perpendicular to the extension direction of the first electrode 1125 (vibration direction along the transverse or second direction Y), the vibration energy can be uniformly diffused along the length direction of the first adapter 1123 (third direction Z), covering the entire preset welding area (the second length L2 is 50%-100% of the first length L1).

[0262] In addition, the lateral welding is adapted to the stress characteristics of the first tab 1125. The first tab 1125 mainly bears the tensile force along the extension direction during battery operation. The welding area formed by the lateral welding extends along the third direction Z, and its tensile force direction is consistent with the stress direction of the first tab 1125. This can improve the fatigue resistance of the welded joint and reduce the joint failure caused by stress cycling during long-term use.

[0263] During the welding process, the welding head vibrates along the second direction Y, causing high-frequency friction between the welding surfaces of the first electrode 1125 and the first adapter 1123, achieving interatomic bonding and forming the first welding area 1130. Increasing the size of the welding head in the third direction Z increases the coverage area of ​​the first welding area 1130 in the third direction Z, thereby maximizing the area of ​​the first welding area 1130.

[0264] In this embodiment, the vibration direction of the transverse welding is parallel to the width direction (second direction Y) of the first adapter 1123, which enables the welding energy to be evenly distributed on the welding surface, which helps to reduce the problem of energy concentration or dispersion. The transverse welding process can ensure that the welding area is fully extended, forming a sufficiently large welding area, improving the current carrying capacity, ensuring welding quality, reducing the risk of false welding, and improving the reliability of the first polarity conduction path.

[0265] In some embodiments, a second electrode terminal 1128 and a plurality of second adapters 1127 are prefabricated; each electrode assembly 1122 has a second tab 1126, and while each first tab 1125 is welded to each first adapter 1123 in a one-to-one correspondence, each second tab 1126 is also welded to each second adapter 1127 in a one-to-one correspondence; while the plurality of first adapters 1123 are all welded to the first electrode terminal 1124, the plurality of second adapters 1127 are also welded to the second electrode terminal 1128 to form an integral electrode assembly.

[0266] While pre-setting the outer shell 1121, the first electrode terminal 1124, the electrode assembly 1122 and the first adapter 1123, the second electrode terminal 1128 and the second adapter 1127 can also be prepared at the same time. The structure and size of the second adapter 1127 can be the same as the first adapter 1123, and it can be prepared by cutting or stamping.

[0267] The first electrode 1125 and the second electrode 1126 have opposite polarities, one being a positive electrode and the other a negative electrode. Therefore, the corresponding first electrode terminal 1124 and second electrode terminal 1128 are positive electrode terminals and negative electrode terminals, respectively. For details, please refer to the above embodiment, which will not be repeated here.

[0268] During the preparation of the electrode assembly, the first tab 1125 on the electrode assembly 1122 is welded to the first adapter 1123 on the welding equipment 1193. After welding is completed or at the same time as welding, the second tab 1126 and the second adapter 1127 can also be welded on the welding equipment 1193. Without changing the work station, the first adapter 1123 and the second adapter 1127 can be connected to the electrode assembly 1122 during welding, which helps to improve the efficiency of welding and assembly.

[0269] In other words, this step uses welding equipment 1193 to simultaneously perform ultrasonic welding of the positive and negative electrode tabs to the adapter pieces. The positioning accuracy and welding parameters of the two welding positions are adapted to the connection requirements of the first and second electrode tabs 1126 and the adapter pieces, respectively, to ensure that there is no mutual interference during the synchronous welding process and to guarantee the welding quality.

[0270] Next, all the second adapter pieces 1127 are welded to the second electrode terminal 1128. This step can be completed simultaneously by a multi-channel laser welding device 1193 to weld the adapter pieces to the electrode terminals of the positive and negative electrodes. The welding methods are adapted to the structural designs of the first electrode terminal 1124 and the second electrode terminal 1128 (such as groove welding, cross-type welding, etc.) to ensure that the positive and negative electrodes form a reliable electrical connection at the same time, and finally form an integrated electrode assembly (including a complete conductive path for the positive and negative electrodes).

[0271] After welding, the integrated electrode assembly (including positive and negative electrode structures) is assembled with the outer shell 1121. The assembly process and sealing treatment ensure the sealing performance of the accommodating cavity 11211.

[0272] In this embodiment, since the adapter adopts a split structure of multiple second adapters 1127, each second tab 1126 and each second adapter 1127 can be independently welded, making the welding method more flexible. Furthermore, the welding area between the second tab 1126 and the second adapter 1127 can be increased through a transverse welding process, thereby improving the current carrying capacity between the second tab 1126 and the second adapter 1127. In addition, when the first tab 1125 is welded to the first adapter 1123, the second tab 1126 and the second adapter 1127 can be welded simultaneously on the welding equipment 1193 without the need for a robotic arm or other equipment to change the workstation, so as to complete the welding of the adapter and the electrode assembly 1122, thereby improving the manufacturing efficiency.

[0273] In some embodiments, refer to Figure 6 and Figure 7 As shown, the second electrode 1126 and the second adapter 1127 are ultrasonically welded, and the ultrasonic welding method is transverse welding.

[0274] Specifically, the second tab 1126 and the second adapter 1127 are also connected by a transverse welding process. The second welding area 1140 formed by the transverse welding extends along the third direction Z. Its tensile force direction is consistent with the force direction of the second tab 1126, which can improve the fatigue resistance of the welded joint and reduce the joint failure caused by stress cycle during long-term use.

[0275] During the welding process, the welding head vibrates along the second direction Y, causing high-frequency friction between the welding surfaces of the second tab 1126 and the second adapter 1127, achieving interatomic bonding and forming the second welding region 1140. Increasing the size of the welding head in the third direction Z increases the coverage area of ​​the second welding region 1140 in the third direction Z, thereby maximizing the area of ​​the second welding region 1140.

[0276] In this embodiment, the vibration direction of the transverse welding is parallel to the width direction (second direction Y) of the second adapter 1127, which enables the welding energy to be evenly distributed on the welding surface, which helps to reduce the problem of energy concentration or dispersion. The transverse welding process can ensure that the welding area is fully extended, forming a sufficiently large welding area, improving the current carrying capacity, ensuring welding quality, reducing the risk of false welding, and improving the reliability of the first polarity conduction path.

[0277] It is evident that transverse welding exhibits superior vibration uniformity, effectively increasing the welding area and thus enhancing the current-carrying capacity of the battery cell 1120. Combined with the back-to-back arrangement of the two electrode assemblies 1122, welding efficiency and quality can be improved without increasing the height of the electrode tabs, thereby increasing the welding area between the electrode tabs and the adapter.

[0278] The above are merely preferred embodiments of this application, and only specifically describe the technical principles of this application. These descriptions are only for explaining the principles of this application and should not be construed as limiting the scope of protection of this application in any way. Based on this explanation, any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application, as well as other specific embodiments of this application that can be conceived by those skilled in the art without creative effort, should be included within the scope of protection of this application.

Claims

1. A battery cell, characterized in that, include: The outer casing has a receiving cavity and a first end wall; The first electrode terminal is disposed on the first end wall; At least two electrode assemblies are disposed within the accommodating cavity, and each electrode assembly includes a first electrode tab. At least two first adapters are provided, each first adapter corresponding to a first tab, and the first tab of each electrode assembly is electrically connected to the first electrode terminal through the corresponding first adapter.

2. The battery cell as described in claim 1, characterized in that, Along a first direction, the first electrode terminal is disposed toward the end of the electrode assembly where the first tab is provided, and a plurality of the electrode assemblies are stacked sequentially in a second direction, the second direction being perpendicular to the first direction; In the second direction, a plurality of first adapters are arranged sequentially, and any two adjacent first adapters are spaced apart in the second direction.

3. The battery cell as described in claim 1, characterized in that, Along a first direction, the first electrode terminal is disposed toward the end of the electrode assembly where the first tab is provided, and a plurality of the electrode assemblies are stacked sequentially in a second direction; in a third direction, the first adapter has a first length; the first tab is welded to the first adapter to form a first welding area, and the first welding area has a second length in a third direction, the second length being 50%-100% of the first length; the first direction, the second direction, and the third direction are perpendicular to each other.

4. The battery cell as described in claim 1, characterized in that, Along the first direction, the first electrode terminal is disposed toward the end of the electrode assembly that has the first tab; along the first direction, the end of the first electrode terminal that faces each of the first tabs has a first groove structure corresponding to each of the first adapters, and the first adapter is at least partially accommodated in the first groove structure.

5. The battery cell as described in claim 1, characterized in that, Along a first direction, the first electrode terminal is disposed toward the end of the electrode assembly where the first tab is provided; a plurality of the electrode assemblies are stacked sequentially in a second direction, the second direction being perpendicular to the first direction; each first tab is welded to each first adapter at a first position to form a first welding area; and the first electrode terminal is welded to each first adapter at a second position to form a second welding area. In the second direction, the extended portion of the first electrode terminal connected to the first adapter extends beyond the first position, such that the first welding area and the second welding area have at least an overlapping portion; or, the extended portion of the first electrode terminal connected to the first adapter avoids the first position, such that the first welding area and the second welding area are spaced apart.

6. The battery cell as described in claim 1, characterized in that, Along a first direction, the first electrode terminal is disposed toward the end of the electrode assembly where the first electrode tab is provided. A plurality of the electrode assemblies are stacked sequentially in a second direction, which is perpendicular to the first direction. The first electrode terminal is welded to each of the first adapters at a second position to form a second welding area. Between any two adjacent first adapters, the second welding area spans across the two adjacent first adapters.

7. The battery cell as described in claim 1, characterized in that, The electrode assembly has two parts. In the first direction, the first electrode terminal is disposed towards the end of the electrode assembly where the first tab is located. In the second direction, the first electrode terminal has two protruding first outer edges, and the two first outer edges are respectively electrically connected to the two first adapters. The first direction is perpendicular to the second direction.

8. The battery cell as described in claim 1, characterized in that, The battery cell further includes a second electrode terminal and a second adapter. The second electrode terminal is disposed on the first end wall and is arranged at a distance from the first electrode terminal. Each electrode assembly also includes a second tab, and the second tab of each electrode assembly is electrically connected to the second electrode terminal through the second adapter.

9. The battery cell as described in claim 8, characterized in that, Along the first direction, the second electrode terminal is disposed toward the end of the electrode assembly that has the second electrode tab, and a plurality of the electrode assemblies are stacked sequentially in the second direction, the second direction being perpendicular to the first direction; In the second direction, a plurality of second adapters are arranged sequentially, with any two adjacent second adapters spaced apart in the second direction.

10. The battery cell as described in claim 8, characterized in that, Along the first direction, the second electrode terminal is disposed toward the end of the electrode assembly that has the second tab, and a plurality of the electrode assemblies are stacked sequentially in the second direction; in the third direction, the second adapter has a third length; the second tab is welded to the second adapter to form a third welding area, and the third welding area has a fourth length in the third direction, the fourth length being 50%-100% of the third length; the first direction, the second direction, and the third direction are mutually perpendicular.

11. The battery cell as described in claim 8, characterized in that, Along the first direction, the second electrode terminal is disposed at the end of the electrode assembly that has the second tab; along the first direction, the side of the second electrode terminal facing each of the second tabs has a second groove structure corresponding to each of the second adapters, and the second adapter is at least partially accommodated in the second groove structure.

12. The battery cell as described in claim 8, characterized in that, Along a first direction, the second electrode terminal is disposed toward the end of the electrode assembly that has the second tab. A plurality of electrode assemblies are stacked sequentially in a second direction, the second direction being perpendicular to the first direction. Each second tab is welded to each second adapter at a third position to form a third welding area. The second electrode terminal is welded to each second adapter at a fourth position to form a fourth welding area. In the second direction, the extended portion of the second electrode terminal connected to the second adapter extends beyond the third position, such that the third welding area and the fourth welding area at least overlap. Alternatively, the extended portion of the second electrode terminal connected to the second adapter avoids the third position, such that the third welding area and the fourth welding area are spaced apart.

13. The battery cell as described in claim 8, characterized in that, Along the first direction, the second electrode terminal is disposed toward the end of the electrode assembly that has the second electrode tab, and a plurality of the electrode assemblies are stacked sequentially in the second direction, which is perpendicular to the first direction; the second electrode terminal is welded to each of the second adapters at a fourth position to form a fourth welding area, and the fourth welding area spans between any two adjacent second adapters.

14. The battery cell as described in claim 8, characterized in that, The electrode assembly has two parts. In the first direction, the second electrode terminal is disposed towards the end of the electrode assembly where the second tab is located. In the second direction, the second electrode terminal has two protruding second outer edges, and the two second outer edges are respectively electrically connected to the two second adapters. The first direction is perpendicular to the second direction.

15. The battery cell as described in claim 8, characterized in that, The plurality of second adapters in the plurality of electrode assemblies are integral structures.

16. A battery device, characterized in that, The battery device includes a battery cell as described in any one of claims 1-15.

17. An electrical device, characterized in that, The electrical device includes a single battery cell as described in any one of claims 1-15; or... The electrical device includes the battery device as described in claim 16, the battery device being used to store or provide electrical energy.

18. A method for preparing a single battery cell, characterized in that, The preparation method is used to prepare the battery cell according to any one of claims 1-15, the method comprising: The prefabricated housing, the first electrode terminal, multiple electrode assemblies, and multiple first adapters, each of the electrode assemblies having a first tab; Each of the first electrode tabs is welded to each of the first adapter pieces; Multiple first adapters are welded to the first electrode terminals to form an integral electrode assembly; The electrode assembly is assembled with the housing.

19. The method for preparing a battery cell as described in claim 18, characterized in that, The first electrode tab and the first adapter are ultrasonically welded together, and the ultrasonic welding method is transverse welding.

20. The method for preparing a single battery cell as described in claim 18 or 19, characterized in that, The first electrode assembly is prefabricated with a second electrode terminal and a plurality of second adapters. Each electrode assembly has a second tab. While each first tab is welded to each first adapter, each second tab is also welded to each second adapter. While the plurality of first adapters are welded to the first electrode terminal, the plurality of second adapters are also welded to the second electrode terminal to form an integral electrode assembly.

21. The method for preparing a single battery cell as described in claim 20, characterized in that, The second electrode tab and the second adapter are ultrasonically welded together, and the ultrasonic welding method is transverse welding.

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