Battery monomer, battery device and electric equipment

Abstract

The embodiment of the utility model discloses a battery monomer, a battery device and electric equipment. The battery cell comprises: an electrode assembly comprising a main body part and a tab; an electrode terminal; the connecting component comprises a tab connecting part, a transition part and an electrode terminal connecting part; the electrode terminal connecting part and the tab connecting part are at least partially stacked along a first direction, and the first direction is an arrangement direction of the electrode terminal and the electrode assembly; the transition part is respectively connected with the electrode terminal connecting part and the tab connecting part, and the connecting member is bent at the transition part; the transition part comprises an inner side transition layer and an outer side transition layer which are stacked in the thickness direction of the transition part; under the condition that the connecting component is in an unfolded state, the outer side transition layer is provided with a first groove which is sunken away from the inner side transition layer, and a gap is formed between the inner side transition layer and the first groove in the thickness direction of the transition part. According to the battery monomer, the battery device and the electric equipment provided by the embodiment of the invention, the reliability of the battery monomer can be improved.

Description

Technical Field

[0001] This application relates to the field of batteries, and more specifically, to a battery cell, a battery device, and an electrical appliance. Background Technology

[0002] Energy conservation and emission reduction are key to the sustainable development of the automotive industry, and electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of this sustainable development. For electric vehicles, battery technology is a crucial factor in their development.

[0003] A typical battery cell includes a casing, electrode terminals, electrode assemblies, and connecting members. The electrode terminals are located on the walls of the casing; the electrode assemblies are located inside the casing and have tabs; the connecting members are used to electrically connect the electrode terminals and the tabs. Therefore, how to design the connecting members to improve the energy density of a battery cell is an important research direction in the battery field. Utility Model Content

[0004] This application provides a battery cell, a battery device, and an electrical appliance that can improve the reliability of the battery cell.

[0005] In a first aspect, a battery cell is provided, comprising: an electrode assembly including a main body and a tab; an electrode terminal; and a connecting member including a tab connection portion, a transition portion, and an electrode terminal connection portion, the tab connection portion being for connection with the tab, and the electrode terminal connection portion being for connection with the electrode terminal; the electrode terminal connection portion and the tab connection portion being at least partially stacked along a first direction, the first direction being the arrangement direction of the electrode terminal and the electrode assembly; the transition portion connecting the electrode terminal connection portion and the tab connection portion respectively, and the connecting member being bent at the transition portion; the transition portion including an inner transition layer and an outer transition layer stacked along the thickness direction of the transition portion; when the connecting member is in an unfolded state, the outer transition layer has a first groove recessed away from the inner transition layer, and a gap exists between the inner transition layer and the first groove along the thickness direction of the transition portion.

[0006] Therefore, the transition portion of the connecting member of the battery cell in this embodiment includes an inner transition layer and an outer transition layer stacked along its thickness direction, i.e., the transition portion is a multi-layer structure. At the same thickness, a multi-layer structure is easier to bend than a single-layer structure. Therefore, by providing a multi-layer transition portion, the risk of cracking of the connecting member at the transition portion can be reduced. Furthermore, when the connecting member is in the unfolded state, the outer transition layer has a first groove recessed away from the inner transition layer, and a gap exists between the inner transition layer and the first groove along the thickness direction of the transition portion. Considering that the circumferential length of the outer transition layer is greater than that of the inner transition layer when the connecting member is bent, compared to the case where multi-layer structures are tightly fitted without gaps, the outer transition layer in this embodiment has a first groove, creating a gap between the first groove and the inner transition layer. This makes the inner transition layer less prone to wrinkling or bulging after bending, or reduces wrinkling and bulging, thus reducing the pressure of the connecting member on the electrode assembly. This improves both the stability and reliability of the connecting member and the stability of the electrode assembly, thereby improving the reliability of the battery cell.

[0007] In some embodiments, when the connecting member is in the unfolded state, the inner transition layer has a second groove recessed toward the outer transition layer, and a gap exists between the second groove and the first groove. Providing grooves in both the inner and outer transition layers facilitates bending of the transition portion, reduces wrinkles and bulges in the inner transition layer, and simplifies processing.

[0008] In some embodiments, when the connecting member is in the unfolded state, the depth H1 of the first groove and the depth H2 of the second groove satisfy: H2 ≤ 2 / 3H1; and / or, when the connecting member is in the unfolded state, the maximum dimension W1 of the first groove along the second direction and the maximum dimension W2 of the second groove along the second direction satisfy: W2 ≤ 2 / 3W1, where the second direction is the arrangement direction of the electrode terminal connection portion, the transition portion, and the tab connection portion when the connecting member is in the unfolded state. Setting H2 ≤ 2 / 3H1 can increase the gap between the inner and outer transition layers, thereby effectively reducing wrinkles and bulges in the inner transition layer when the connecting member is in the bent state. Setting the maximum dimension W1 of the first groove along the second direction to be greater than the maximum dimension W2 of the second groove along the second direction can facilitate bending of the transition portion and effectively reduce wrinkles and bulges in the inner transition layer.

[0009] In some embodiments, the tab connection portion is the area where the connecting member is welded to the tab, and the electrode terminal connection portion is the area where the connecting member is welded to the electrode terminal. Along the arrangement direction of the electrode terminal connection portion, the transition portion, and the tab connection portion, the difference between the length of the outer transition layer and the length of the inner transition layer is greater than or equal to 0.5 mm, and less than or equal to 20 times the thickness of the inner transition layer. By setting the difference between the length of the outer transition layer and the length of the inner transition layer to be greater than or equal to 0.5 mm, it is easier to achieve a gap between the first grooves of the inner and outer transition layers, thereby reducing the bulging of the inner transition layer when the connecting member bends and improving structural stability. Simultaneously, setting the difference between the length of the outer transition layer and the length of the inner transition layer to be less than or equal to 20 times the thickness of the inner transition layer can limit the length of the outer transition layer from being too long and also limit the gap between the first grooves of the inner and outer transition layers from being too large, reducing the space occupied by the transition portion and increasing the energy density of the battery cell.

[0010] In some embodiments, the inner transition layer has a protruding structure that protrudes away from the outer transition layer, and the protrusion height of the protruding structure is less than or equal to 5 times the thickness of the inner transition layer. This limits the size of the protruding structure, reduces its space occupation, and increases the energy density of the battery cell. In addition, the smaller size of the protruding structure can reduce the compression of the connecting members onto the electrode assembly, reduce damage to the electrode assembly, and improve the performance and stability of the battery cell.

[0011] In some embodiments, the tab connection includes a first structural layer and a second structural layer stacked along the first direction. The first structural layer and the outer transition layer are integrally formed, and the second structural layer and the inner transition layer are integrally formed. This eliminates the need for additional processing and fixing between the tab connection and the transition layer; for example, welding the tab connection to the transition layer is unnecessary, simplifying the processing steps and improving the structural stability of the connecting component.

[0012] In some embodiments, along the first direction, the tab is located between the first structural layer and the second structural layer. When the tab is fixedly connected to the tab connection portion, for example, when the tab is welded to the tab connection portion, the clamp used for welding can directly clamp the first structural layer and the second structural layer without directly contacting the intermediate tab, reducing the risk of the clamp damaging the tab. For example, it can reduce the risk of the tab cracking, thereby improving the stability and reliability of the tab.

[0013] In some embodiments, the electrode terminal connection includes a third structural layer and a fourth structural layer stacked along the first direction. The third structural layer and the outer transition layer are integrally formed, and the fourth structural layer and the inner transition layer are integrally formed. No additional processing or fixing is required between the electrode terminal connection and the transition layer; for example, welding between the electrode terminal connection and the transition layer is unnecessary, simplifying the processing steps and improving the structural stability of the connection component.

[0014] In some embodiments, along the first direction, the third structural layer is located between the electrode terminal and the fourth structural layer to facilitate electrical connection between the electrode terminal connection portion and the electrode terminal.

[0015] In some embodiments, the third structural layer and the fourth structural layer are welded or connected by conductive adhesive, which facilitates the electrical connection between the third structural layer and the fourth structural layer, and also facilitates the electrical connection between the electrode terminal connection portion and the electrode terminal, thereby improving processing efficiency.

[0016] In some embodiments, the connecting member is provided with an opening, at least a portion of which is located in the transition section. On the one hand, the opening can reduce the current carrying capacity of the connecting member in the area surrounding the opening, thereby facilitating the melting of the connecting member in the area where the opening is located when a short circuit occurs in a battery cell; on the other hand, the fact that at least a portion of the opening is located in the transition section can weaken the structural strength of the transition section, making it easier to bend.

[0017] In some embodiments, the transition portion has openings on both sides along a third direction, which is perpendicular to the first and second directions. The second direction is the arrangement direction of the electrode terminal connection portion, the transition portion, and the tab connection portion when the connecting member is in the unfolded state. Considering that the transition portion is located in the middle of the connecting member along the second direction, having an opening at each end of the transition portion along the third direction makes the transition portion approximately symmetrical, and the connecting member also approximately symmetrical. This balances the current-carrying capacity of different regions of the connecting member, thereby improving the structural stability of the connecting member.

[0018] In some embodiments, when the connecting member is in the unfolded state, the size of the opening along the second direction is greater than or equal to 10 mm, so as to effectively determine the weak point of the connecting member when overcurrent occurs, so that the connecting member will melt at the weak point when a short circuit occurs in a battery cell.

[0019] In some embodiments, the tab includes a converging portion and a fixing portion. The converging portion is bent relative to the fixing portion, and the converging portion is connected to the main body portion. The fixing portion is connected to the tab connecting portion. The tab in this embodiment can be bent only once, simplifying the structure of the tab and reducing the risk of cracking at the bend, thereby improving the structural stability and reliability of the electrode assembly.

[0020] In a second aspect, a battery device is provided, comprising: a plurality of battery cells, wherein the battery cells are those described in the first aspect or any embodiment of the first aspect.

[0021] Thirdly, an electrical device is provided, comprising: a battery device including a battery cell as described in the first aspect or any embodiment of the first aspect, the battery device being used to supply power to the electrical device.

[0022] In some embodiments, the electrical equipment is a vehicle, a ship, or a spacecraft. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a vehicle according to one embodiment of this application;

[0024] Figure 2 This is an exploded view of a battery device according to an embodiment of this application;

[0025] Figure 3 This is a schematic diagram of the structure of a battery cell according to an embodiment of this application;

[0026] Figure 4 This is a cross-sectional schematic diagram of a battery cell according to an embodiment of this application;

[0027] Figure 5 This is a cross-sectional schematic diagram of a portion of the structure of a battery cell according to an embodiment of this application;

[0028] Figure 6 This is a schematic diagram of a partial structure of a battery cell according to an embodiment of this application;

[0029] Figure 7 This is a side view of a connecting member in an unfolded state according to an embodiment of this application;

[0030] Figure 8 This is a top view of a connecting member in an unfolded state according to an embodiment of this application;

[0031] Figure 9 This is a schematic diagram of another side view of a connecting member according to an embodiment of this application;

[0032] Figure 10 This is a side view of the connecting member in the unfolded state according to another embodiment of this application;

[0033] Figure 11 This is a top view of the connecting member in the unfolded state according to another embodiment of this application;

[0034] Figure 12 This is a top view of the connecting member in the unfolded state according to another embodiment of this application.

[0035] The accompanying drawings are not drawn to scale.

[0036] Figure label:

[0037] 1-Vehicle; 30-Controller; 40-Motor; 10-Battery Unit; 11-Casing; 111-First Casing Section; 112-Second Casing Section; 20-Battery Cell; 21-Casing; 211-Housing; 212-End Cap; 22-Electrode Assembly; 221-Main Body; 222-Electrode Tab; 2221-Converging Section; 2222-Fixing Section; 23-Electrode Terminal; 24-Connecting Member; 241-Electrode Tab Connection Section; 24 11-First structural layer; 2412-Second structural layer; 242-Transition section; 2421-Outer transition layer; 24211-First groove; 2422-Inner transition layer; 24221-Bending line; 24222-Second groove; 24223-Protruding structure; 243-Electrode terminal connection section; 2431-Third structural layer; 2432-Fourth structural layer; 2433-Welding area; 244-Opening; 25-Support. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0039] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application 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 description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0040] In this application, the reference to "embodiment" means that a specific 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 mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0041] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0042] 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, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0043] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0044] In this application, "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).

[0045] The battery apparatus mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells connected in series, parallel, or mixed connections via a busbar.

[0046] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells.

[0047] As an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells together to form an independent module. As another example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0048] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cells housed within the housing.

[0049] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0050] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0051] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0052] The battery cell 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.

[0053] A battery cell typically includes a casing, electrode terminals, electrode assemblies, and connecting members. The electrode terminals are located on the walls of the casing, while the electrode assemblies are housed within the casing, each assembly having tabs. The connecting members electrically connect the electrode terminals and the tabs. To facilitate battery cell assembly and improve space utilization within the cell, the tabs are bent after being connected to the connecting members, allowing the electrode assemblies to be inserted into the casing. Because the connecting members have high strength and are welded to both the tabs and electrode terminals, the electrode assemblies are prone to movement relative to the casing during battery cell transportation or use, especially when the cell is subjected to vibration. This can lead to fatigue cracking at the bends in the tabs, resulting in poor current-carrying capacity of the battery cell. Therefore, this problem can be solved by bending the connecting members. For example, the bends in the connecting members can be designed with a multi-layered structure. This facilitates bending and allows the bent connecting members to absorb the forces generated by the movement of the electrode assemblies, dispersing stress at the bends in the tabs, reducing the risk of fatigue cracking, and ultimately improving the reliability of the battery cell. However, when the bending point of the connecting member is set as a multi-layer structure, bending the connecting member will stretch the outer structural layer and compress the inner structural layer. However, the metal connecting member itself is difficult to stretch and contract freely, and when the multi-layer connecting members are closely attached to each other, they will restrict each other during the bending process, causing the inner structural layer to be squeezed, which will create redundancy. This will cause the connecting member to squeeze the electrode assembly downward, which may damage the electrode assembly.

[0054] Therefore, the battery cell, battery device, and electrical equipment provided in this application can solve the above-mentioned problems. The battery cell in this application includes an electrode assembly, electrode terminals, and a connecting member. The connecting member includes a tab connection portion, a transition portion, and an electrode terminal connection portion. The tab connection portion is used to connect with a tab, and the electrode terminal connection portion is used to connect with an electrode terminal, so that an electrical connection between the electrode terminal and the tab is achieved through the connecting member. The tab connection portion and the electrode terminal connection portion are at least partially stacked along a first direction, which is the direction in which the tab and the electrode terminal are arranged. The transition portion connects the tab connection portion and the electrode terminal connection portion respectively, and the connecting member is bent at the transition portion.

[0055] The transition section includes an inner transition layer and an outer transition layer stacked along its thickness direction, i.e., the transition section is a multi-layer structure. At the same thickness, a multi-layer structure is easier to bend than a single-layer structure. Therefore, by providing a multi-layer transition section, the risk of cracking of the connecting member at the transition section can be reduced. Furthermore, when the connecting member is in the unfolded state, the outer transition layer has a first groove recessed away from the inner transition layer, and a gap exists between the inner transition layer and the first groove along the thickness direction of the transition section. Considering the bending of the connecting member, compared to a multi-layer structure that is tightly fitted without gaps, the outer transition layer of this embodiment has a first groove, creating a gap between the first groove and the inner transition layer. This makes the inner transition layer less prone to wrinkling or bulging after bending, or reduces wrinkling and bulging, thus reducing the pressure of the connecting member on the electrode assembly. This improves both the stability and reliability of the connecting member and the stability of the electrode assembly, thereby improving the reliability of the battery cell.

[0056] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use battery devices.

[0057] Electrical devices can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This application does not impose any special limitations on the above-mentioned electrical devices.

[0058] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device.

[0059] For example, such as Figure 1The diagram shown is a structural schematic of a vehicle 1 according to one embodiment of this application. Vehicle 1 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A motor 40, a controller 30, and a battery device 10 can be installed inside vehicle 1. The controller 30 controls the battery device 10 to supply power to the motor 40. For example, the battery device 10 can be installed at the bottom, front, or rear of vehicle 1. The battery device 10 can be used to power vehicle 1. For example, the battery device 10 can serve as the operating power source for vehicle 1, for example, to meet the electrical system requirements of vehicle 1, such as for starting, navigation, and operation. In another embodiment of this application, the battery device 10 can not only serve as the operating power source for vehicle 1, but also as the driving power source for vehicle 1, replacing or partially replacing gasoline or natural gas to provide driving power for vehicle 1.

[0060] Figure 2 An exploded view of the battery device 10 according to an embodiment of this application is shown. Figure 2 As shown, the battery device 10 of this application embodiment may include a plurality of battery cells 20 to meet different power usage requirements. The shape of the battery cell 20 in this application embodiment can be set according to actual application. For example, the battery cell 20 can be as follows: Figure 2 The cuboid shown can also be different. Figure 2 The embodiments shown are cylindrical or other shapes, but are not limited to these.

[0061] It should be understood that, such as Figure 2 As shown, the battery device 10 of this embodiment may further include a housing 11, which can be used to accommodate multiple battery cells 20. The housing 11 of this embodiment has a hollow interior, and the multiple battery cells 20 are accommodated within the housing 11. The housing 11 may include two parts, referred to herein as a first housing portion 111 and a second housing portion 112, which are fastened together. The shapes of the first housing portion 111 and the second housing portion 112 can be determined according to the shape of the components housed inside, for example, according to the shape of the combination of the multiple battery cells 20 housed inside. At least one of the first housing portion 111 and the second housing portion 112 has an opening. For example, as... Figure 2As shown, the first housing portion 111 and the second housing portion 112 can both be hollow cuboids with one open side each. The openings of the first housing portion 111 and the second housing portion 112 are opposite to each other, and the first housing portion 111 and the second housing portion 112 are interlocked to form a housing 11 with a closed chamber, which can be used to accommodate multiple battery cells 20. The multiple battery cells 20 are connected in parallel, series, or mixed and placed inside the housing 11 formed by the interlocking of the first housing portion 111 and the second housing portion 112.

[0062] For example, unlike Figure 2 As shown, either the first housing portion 111 or the second housing portion 112 may have only one hollow cuboid with an opening, while the other is plate-shaped to cover the opening. Taking the second housing portion 112 as a hollow cuboid with one opening and the first housing portion 111 as a plate-shaped example, then the first housing portion 111 covers the opening of the second housing portion 112 to form a housing 11 with a closed chamber, which can be used to accommodate multiple battery cells 20.

[0063] Figure 3 A schematic diagram of the structure of a battery cell 20 according to an embodiment of this application is shown. For example, the battery cell 20 is shown. Figure 3 This can be a structural schematic diagram of any one of the battery cells 20 included in the battery device 10 of this application embodiment; Figure 4 A cross-sectional schematic diagram of the battery cell 20 according to an embodiment of this application is shown. For example, the... Figure 4 It can be like Figure 3 The cross-sectional view of the battery cell 20 shown is perpendicular to the length direction Y of the battery cell 20. Figure 5 A cross-sectional schematic diagram of a portion of the structure of a battery cell 20 according to an embodiment of this application is shown, for example, Figure 5 It shows Figure 4 Partial structure of the battery cell 20 shown.

[0064] In this embodiment, the battery cell 20 includes an electrode assembly 22, electrode terminals 23, and a connecting member 24. Specifically, the electrode assembly 22 includes a main body 221 and tabs 222; the connecting member 24 includes a tab connecting portion 241, a transition portion 242, and an electrode terminal connecting portion 243. The tab connecting portion 241 is used to connect to the tabs 222, and the electrode terminal connecting portion 243 is used to connect to the electrode terminals 23. The electrode terminal connecting portion 243 and the tab connecting portion 241 are at least partially stacked along a first direction Z, where the first direction Z is the arrangement direction of the electrode terminals 23 and the electrode assembly 22; the transition portion 242 connects to... The electrode terminal connection portion 243 and the tab connection portion 241 are connected, and the connecting member 24 is bent at the transition portion 242; the transition portion 242 includes an inner transition layer 2422 and an outer transition layer 2421 stacked along the thickness direction of the transition portion 242; when the connecting member 24 is in the unfolded state, the outer transition layer 2421 has a first groove 24211 recessed away from the inner transition layer 2422, and there is a gap between the inner transition layer 2422 and the first groove 24211 along the thickness direction of the transition portion 242.

[0065] It should be understood that the shape of the battery cell 20 in this application embodiment can be set according to actual application. For example, the battery cell 20 can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries, etc. This application has no particular limitations. For ease of explanation, as... Figures 3 to 5 As shown, the embodiments of this application are mainly described using a rectangular battery cell 20 as an example.

[0066] The battery cell 20 in this embodiment includes an electrode assembly 22, which typically includes a positive electrode, a negative electrode, and a separator, with the separator disposed between the negative and positive electrodes. During the charging and discharging process of the battery cell 20, active ions (such as lithium ions or sodium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, disposed between the positive and negative electrodes, serves to prevent short circuits between the positive and negative electrodes while allowing active ions to pass through.

[0067] The electrode assembly 22 can be a wound structure, a stacked structure, or a hybrid structure of wound and stacked.

[0068] In some embodiments, the electrode assembly 22 is a wound structure. The positive electrode and the negative electrode are wound into a wound structure.

[0069] In some embodiments, the electrode assembly 22 is a stacked structure. As an example, multiple positive and negative electrodes can be provided, with multiple positive and multiple negative electrodes stacked alternately. As an example, multiple positive electrodes can be provided, and negative electrodes are folded to form multiple stacked folded segments, with a positive electrode sandwiched between adjacent folded segments. As an example, both positive and negative electrodes are folded to form multiple stacked folded segments.

[0070] As an example, multiple separators can be provided, each positioned between any two adjacent positive or negative electrode plates. As another example, separators can be provided continuously, positioned between any two adjacent positive or negative electrode plates by folding or winding.

[0071] In some embodiments, the electrode assembly 22 may be cylindrical, flat, or polygonal in shape.

[0072] In some embodiments, the electrode assembly 22 includes a body portion 221 and tabs 222, the tabs 222 protruding from the body portion 221, and the tabs 222 can conduct current from the electrode assembly 22. It should be understood that each electrode assembly 22 may include a plurality of tabs 222, the plurality of tabs 222 including at least one positive tab and at least one negative tab, wherein the plurality of tabs 222 may be located on the same end face or different end faces of the body portion 221 to accommodate different battery cells 20.

[0073] The battery cell 20 in this embodiment includes electrode terminals 23, which are electrically connected to tabs 222 to output electrical energy. In some embodiments, the battery cell 20 may include a plurality of electrode terminals 23, including at least one positive electrode terminal and at least one negative electrode terminal, wherein the positive electrode terminal is used to be electrically connected to the positive tab and the negative electrode terminal is used to be electrically connected to the negative tab.

[0074] In this embodiment of the application, all electrode terminals 23 of the battery cell 20 can be located on any one or more walls of the battery cell 20, that is, different electrode terminals 23 can be located on the same wall or different walls of the battery cell 20.

[0075] For ease of description, such as Figures 3 to 5As shown in the embodiment, this application takes the electrode assembly 22 as an example, which includes two oppositely arranged tabs 222. Correspondingly, the battery cell 20 also includes two oppositely arranged electrode terminals 23. Furthermore, in this embodiment, the tab 222 refers to any one of the tabs 222 included in the electrode assembly 22, and the electrode terminal 23 refers to the electrode terminal 23 electrically connected to the tab 222. For example, the tab 222 can be a positive tab, then the electrode terminal 23 is a positive electrode terminal; or, the tab 222 can be a negative tab, then the electrode terminal 23 is a negative electrode terminal.

[0076] The electrode terminal 23 in this embodiment can be located on any wall of the battery cell 20. For example, the battery cell 20 includes a housing 21, and the electrode terminal 23 is located on any wall of the housing 21. Exemplarily, the housing 21 in this embodiment can be a steel housing, an aluminum housing, a plastic housing (such as polypropylene), a composite metal housing (such as a copper-aluminum composite housing), or an aluminum-plastic film, etc.

[0077] In some embodiments, the outer casing 21 includes end caps 212 and a housing 211, the housing 211 having an opening, and the end caps 212 covering the opening. The housing 211 may have one or more openings. The end caps 212 may also be provided one or more. For example, in this embodiment of the application, the outer casing 21 includes two end caps 212 disposed opposite to each other, to cover the openings at both ends of the housing 211 respectively; and the electrode terminals 23 of the battery cell 20 are disposed on the end caps 212, but this embodiment of the application is not limited to this.

[0078] The battery cell 20 in this embodiment further includes a connecting member 24 for electrically connecting the electrode terminal 23 and the tab 222. Exemplarily, the connecting member 24 includes a tab connecting portion 241, a transition portion 242, and an electrode terminal connecting portion 243. The tab connecting portion 241 is used to connect to the tab 222, and the electrode terminal connecting portion 243 is used to connect to the electrode terminal 23, thereby achieving an electrical connection between the electrode terminal 23 and the tab 222. For example, the tab connecting portion 241 and the tab 222 can be electrically connected by welding, and / or the electrode terminal connecting portion 243 and the electrode terminal 23 can be electrically connected by welding. This embodiment is not limited to these methods.

[0079] like Figures 3 to 5As shown, in this embodiment, the transition portion 242 of the connecting member 24 connects the electrode terminal connecting portion 243 and the tab connecting portion 241 respectively. The connecting member 24 is bent at the transition portion 242 so that the electrode terminal connecting portion 243 and the tab connecting portion 241 can be at least partially stacked along a first direction Z. Here, the first direction Z is the arrangement direction of the electrode terminals 23 and the electrode assembly 22. For example, in this embodiment, the first direction Z is mainly taken as the height direction of the battery cell 20. By providing a bent connecting member 24, the length or width of the connecting member 24 can be reduced to suit different application scenarios and improve space utilization.

[0080] The electrode terminal connection portion 243 and the tab connection portion 241 of this application embodiment are at least partially stacked along a first direction Z, including: on a plane perpendicular to the first direction Z, the orthographic projections of the electrode terminal connection portion 243 and the tab connection portion 241 at least partially overlap. For example, on a plane perpendicular to the first direction Z, the orthographic projection of the electrode terminal connection portion 243 may cover the orthographic projection of the tab connection portion 241, or the orthographic projection of the tab connection portion 241 may cover the orthographic projection of the electrode terminal connection portion 243, or, as... Figures 3 to 5 As shown, the orthographic projection of the electrode terminal connection portion 243 and the orthographic projection of the tab connection portion 241 partially overlap and partially misalign.

[0081] It should be understood that, such as Figures 3 to 5 As shown, in this embodiment, the transition portion 242 connects the electrode terminal connection portion 243 and the tab connection portion 241, respectively. The electrode terminal connection portion 243 can be the area of ​​the connecting member 24 electrically connected to the electrode terminal 23, and the tab connection portion 241 can be the area of ​​the connecting member 24 electrically connected to the tab 222. The transition portion 242 then covers the entire area between the electrode terminal connection portion 243 and the tab connection portion 241; that is, one end of the transition portion 242 is connected to the electrode terminal connection portion 243, and the other end is connected to the tab connection portion 241. Furthermore, the connecting member 24 is bent at the transition portion 242, meaning the transition portion 242 is bent, so that the electrode terminal connection portion 243 and the tab connection portion 241 of the connecting member 24 can be at least partially stacked along the first direction Z.

[0082] The transition portion 242 in this embodiment is a multi-layer structure, comprising an inner transition layer 2422 and an outer transition layer 2421 stacked along the thickness direction of the transition portion 242. Specifically, the inner transition layer 2422 is located inside the outer transition layer 2421 along the radial direction of the transition portion 242. For example, the transition portion 242 can be a double-layer structure, consisting of an inner transition layer 2422 and an outer transition layer 2421. Alternatively, the transition portion 242 can be a three-layer structure or a structure with more than three layers. In this case, the inner transition layer 2422 and the outer transition layer 2421 can be any two layers included in the transition portion 242, and they can be arranged adjacent to each other or spaced apart along the radial direction of the transition portion 242. Furthermore, the inner transition layer 2422 is located inside the outer transition layer 2421 along the radial direction of the transition portion 242. For ease of explanation, this embodiment primarily uses a double-layer structure for the transition portion 242 as an example, but the embodiment is not limited to this.

[0083] With the same thickness, when the transition portion 242 is a multi-layer structure, it is easier to bend than when the transition portion 242 is a single-layer structure. Therefore, by setting a multi-layer transition portion 242, the risk of cracking of the connecting member 24 in the transition portion 242 can be reduced, thereby improving the stability and reliability of the battery cell 20.

[0084] Figure 6 A schematic diagram of a partial structure of the battery cell 20 according to an embodiment of this application is shown. Figure 6 The connecting member 24 shown is in the deployed state. Figure 6 As shown in the embodiment of this application, the extended state of the connecting member 24 indicates that the included angle between the electrode terminal connecting portion 243 and the electrode tab connecting portion 241 is 180° or approximately 180°, or in other words, the electrode terminal connecting portion 243 and the electrode tab connecting portion 241 are on the same plane or approximately on the same plane. In the extended state, the electrode tab connecting portion 241, the transition portion 242, and the electrode terminal connecting portion 243 of the connecting member 24 are arranged along a second direction L, where the second direction L is the length direction of the connecting member 24.

[0085] For example, the connecting member 24 is in the position of Figure 6 The unfolded state shown can be: the connecting member 24 extends from, for example... Figure 5 The bending state shown is obtained by rotating the electrode terminal connection portion 243 approximately 180°; or, in other words, the connection member 24 is in the position shown. Figure 6 In the unfolded state shown, bending and rotating the electrode terminal connection portion 243 by approximately 180° can achieve the following: Figure 5 The bending state shown.

[0086] Therefore, the unfolded state of the connecting member 24 in this embodiment can be the pre-bent processing state before the connecting member 24 is disposed on the outer shell 21 of the battery cell 20, or it can be the state in which the connecting member 24 is unfolded again after being bent. For ease of description, this embodiment mainly uses the pre-bent processing state of the connecting member 24 as an example, but the relevant description is also applicable to other situations, and will not be repeated here for the sake of brevity.

[0087] In the embodiments of this application, such as Figure 6 As shown, when the connecting member 24 is in the unfolded state, the outer transition layer 2421 has a first groove 24211 recessed away from the inner transition layer 2422, and a gap exists between the inner transition layer 2422 and the first groove 24211 along the thickness direction of the transition portion 242. Specifically, this gap refers to the gap between the surface of the inner transition layer 2422 facing the first groove 24211 and the surface of the first groove 24211 facing the inner transition layer 2422 along the thickness direction of the transition portion 242. That is, by providing the recessed first groove 24211, at least a portion of the internal space of the first groove 24211 can form this gap.

[0088] contrast Figure 5 It is understood that when the connecting member 24 is bent, compared to the case where the multi-layer structure is tightly fitted without gaps when unfolded, the gap between the first groove 24211 of the inner transition layer 2422 and the outer transition layer 2421 provided in this embodiment makes it less likely for the inner transition layer 2422 to wrinkle or bulge after bending, or reduces the number of wrinkles and bulges. This reduces the pressure of the connecting member on the electrode assembly 22, which can improve the stability and reliability of the connecting member 24, as well as the stability of the electrode assembly, and thus improve the reliability of the battery cell.

[0089] It should be understood that when the connecting member 24 in the embodiments of this application is a bent structure, the structure of the tab 222 can be set according to the actual application.

[0090] In some embodiments, the tab 222 includes a converging portion 2221 and a fixing portion 2222. The converging portion 2221 is bent relative to the fixing portion 2222. The converging portion 2221 is connected to the main body portion 221, and the fixing portion 2222 is connected to the tab connecting portion 241. Specifically, as shown... Figures 3 to 6As shown, the converging portion 2221 is connected to the end face of the main body portion 221. The thickness of the converging portion 2221 gradually decreases from the region near the main body portion 221 to the region away from the main body portion 221. That is, the converging portion 2221 is the region where the thickness of the tab 222 gradually narrows. In this embodiment, the thickness of the converging portion 2221 is the dimension of the converging portion 2221 along the thickness direction X of the main body portion 221. The fixing portion 2222 of the tab 222 in this embodiment is connected to the end of the converging portion 2221 away from the main body portion 221 and is bent relative to the converging portion 2221. The fixing portion 2222 is used for electrical connection with the tab connecting portion 241.

[0091] Therefore, the tab 222 in this embodiment can be bent only once, simplifying the structure of the tab 222 and reducing the risk of the tab 222 cracking at the bend, thereby improving the structural stability and reliability of the electrode assembly 22.

[0092] In some embodiments, the battery cell 20 further includes a support 25, at least a portion of which is located between the converging portion 2221 and the fixing portion 2222 to support the tab 222 and improve structural stability.

[0093] In some embodiments, the converging position of the converging portion 2221 in this application embodiment may be located in the middle region or the edge region of the main body portion 221 of the electrode assembly 22. For example, as Figures 3 to 6 As shown, the convergence position of the converging part 2221 can be located at the edge of the main body 221 along the thickness direction X, that is, the area where the thickness of the converging part 2221 is at the edge of the main body 221, and the converging part 2221 and the fixing part 2222 are bent at this edge to save the space occupied by the tab 222 and the connecting member 24 in the thickness direction X of the main body 221, thereby improving the space utilization of the battery cell 20.

[0094] It should be understood that the specific structure of the connecting member 24 in this application embodiment can be set according to actual application. For example, when the transition portion 242 of the connecting member 24 in this application embodiment has a multi-layer structure, the electrode terminal connecting portion 243 can be a single-layer structure or a multi-layer structure, and the electrode tab connecting portion 241 can also be a single-layer structure or a multi-layer structure.

[0095] In some embodiments, the electrode terminal connection portion 243 and / or the tab connection portion 241 are single-layer structures to facilitate electrical connection between the electrode terminal connection portion 243 and the electrode terminal 23, and to facilitate electrical connection between the tab connection portion 241 and the tab 222. For example, the electrode terminal connection portion 243 is typically located on the side of the electrode terminal 23 facing the interior of the battery cell 20, and the tab connection portion 241 may be located on the side of the tab 222 facing the electrode terminal 23, or the tab connection portion 241 may also be on the side of the tab 222 facing the main body portion 221. The embodiments of this application are not limited to this.

[0096] In some embodiments, the tab connection portion 241 includes a first structural layer 2411 and a second structural layer 2412 stacked along a first direction Z. The first structural layer 2411 and the outer transition layer 2421 are integrally formed, and the second structural layer 2412 and the inner transition layer 2422 are integrally formed. For example, when the tab connection portion 241 is configured as a multi-layer structure, the number of structural layers in the tab connection portion 241 can be the same as the number of structural layers in the transition portion 242. Furthermore, each layer of the tab connection portion 241 can be integrally formed with a corresponding layer in the transition portion 242 for ease of processing.

[0097] For example, such as Figures 3 to 6 As shown in the embodiment of this application, the first structural layer 2411 and the second structural layer 2412 included in the tab connection portion 241 are used as examples. The first structural layer 2411 can be integrated with the outer transition layer 2421, and the second structural layer 2412 can be integrated with the inner transition layer 2422. This way, no additional processing or fixing is required between the tab connection portion 241 and the transition portion 242. For example, it is not necessary to weld the tab connection portion 241 and the transition portion 242, which can simplify the processing steps and improve the structural stability of the connecting member 24.

[0098] It should be understood that when the tab connection portion 241 has a multi-layer structure, the tab 222 can be located on any side of the tab connection portion 241 or in the middle of the tab connection portion 241.

[0099] In some embodiments, along the first direction Z, the tab 222 is located between the first structural layer 2411 and the second structural layer 2412. When the tab 222 is fixedly connected to the tab connecting portion 241, for example, when the tab 222 is welded to the tab connecting portion 241, the clamp used for welding can directly clamp the first structural layer 2411 and the second structural layer 2412 without directly contacting the intermediate tab 222, reducing the risk of the clamp damaging the tab 222. For example, it can reduce the risk of the tab 222 cracking, thereby improving the stability and reliability of the tab 222.

[0100] In some embodiments, the tab 222 and the tab connection portion 241 can be fixed by ultrasonic welding, but the embodiments of this application are not limited thereto.

[0101] In some embodiments, the tab connection portion 241 may also be located in other positions. For example, the multi-layer structure of the tab connection portion 241 may all be located on the side of the tab 222 facing the electrode terminal 23, or it may be located on the side of the tab 222 facing the main body portion 221 of the electrode assembly 22, to suit different application scenarios.

[0102] In some embodiments, when the tab connection portion 241 has a multi-layer structure, the electrode terminal connection portion 243 can be a single-layer structure or a multi-layer structure.

[0103] In some embodiments, the electrode terminal connection portion 243 includes a third structural layer 2431 and a fourth structural layer 2432 stacked along a first direction Z. The third structural layer 2431 and the outer transition layer 2421 are integrally formed, and the fourth structural layer 2432 and the inner transition layer 2422 are integrally formed. For example, when the electrode terminal connection portion 243 is configured as a multi-layer structure, the number of structural layers included in the electrode terminal connection portion 243 can be the same as the number of structural layers in the transition portion 242. Furthermore, each layer of the electrode terminal connection portion 243 can be integrally formed with a corresponding layer of the transition portion 242 to facilitate processing.

[0104] For example, such as Figures 3 to 6 As shown in the embodiment of this application, the third structural layer 2431 and the fourth structural layer 2432 included in the electrode terminal connection portion 243 are used as examples. The third structural layer 2431 can be integrated with the outer transition layer 2421, and the fourth structural layer 2432 can be integrated with the inner transition layer 2422. This way, no additional processing or fixing is required between the electrode terminal connection portion 243 and the transition portion 242. For example, it is not necessary to weld the electrode terminal connection portion 243 and the transition portion 242, which can simplify the processing steps and improve the structural stability of the connecting member 24.

[0105] In some embodiments, along the first direction Z, the third structural layer 2431 is located between the electrode terminal 23 and the fourth structural layer 2432. That is, along the first direction Z, the multi-layer structure of the electrode terminal connection portion 243 is located on the side of the electrode terminal 23 facing the tab 222, so as to realize the electrical connection between the electrode terminal connection portion 243 and the electrode terminal 23. For example, the two can be connected and fixed by welding.

[0106] In some embodiments, the third structural layer 2431 and the fourth structural layer 2432 are welded or connected by conductive adhesive, which facilitates the electrical connection between the third structural layer 2431 and the fourth structural layer 2432, and also facilitates the electrical connection between the electrode terminal connection portion 243 and the electrode terminal 23, thereby improving processing efficiency.

[0107] In some embodiments, when the electrode terminal connection portion 243 has a multi-layer structure, the tab connection portion 241 can be a single-layer structure or a multi-layer structure.

[0108] In some embodiments, the connecting member 24 can be a multi-layered structure, wherein the multi-layered structures can be connected together by welding methods such as ultrasonic welding and molecular diffusion welding, or by conductive adhesive. Figures 3 to 6 As shown, the first structural layer 2411, the outer transition layer 2421, and the third structural layer 2431 can be an integral structure, and the second structural layer 2412, the inner transition layer 2422, and the fourth structural layer 2432 can also be an integral structure, in order to simplify the processing steps of the connecting member 24 and improve the structural stability. For ease of description, this application embodiment uses a double-layer structure of the connecting member 24 as an example, but the embodiments of this application are not limited to this.

[0109] It should be understood that the gap between the first groove 24211 of the inner transition layer 2422 and the outer transition layer 2421 in the embodiments of this application can be obtained in a variety of ways.

[0110] Figure 7 This illustration shows a side view of the connecting member 24 in an unfolded state according to an embodiment of this application. Figure 7 It can be like Figures 3 to 6 One possible implementation of the unfolded state of the connecting member 24 included in any of the accompanying drawings. Figure 8 This illustration shows a top view of the connecting member 24 in an unfolded state according to an embodiment of this application. Figure 8 It can be Figure 7 A top view of the connecting member 24 shown.

[0111] In some embodiments, when the connecting member 24 is in the deployed state, the inner transition layer 2422 is flush with the tab connection portion 241 and / or the electrode terminal connection portion 243. If the outer transition layer 2421 is provided with a first groove 24211 recessed away from the inner transition layer 2422, a gap exists between the inner transition layer 2422 and the first groove 24211. Figure 7 and Figure 8As shown, when the connecting member 24 is in the unfolded state, the inner transition layer 2422 is set to be relatively flat, while the outer transition layer 2421 has a first groove 24211. A gap exists between the surface of the first groove 24211 facing the inner transition layer 2422 and the surface of the inner transition layer 2422 facing the first groove 24211. This gap can be used to reduce wrinkles and bulges in the inner transition layer 2422 when the connecting member 24 is bent.

[0112] The gap between the inner transition layer 2422 and the outer transition layer 2421 can be formed simply by setting the first groove 24211 on the outer transition layer 2421. This process is simple and easy to implement.

[0113] In some embodiments, such as Figure 7 and Figure 8 As shown, when the connecting member 24 is in the unfolded state, the inner transition layer 2422 is provided with a bend line 24221. For example, the bend line 24221 can be a crease, a notch, or other markings, which facilitates positioning based on the bend line 24221 when bending the inner transition layer 2422, and can also reduce the structural strength of the inner transition layer 2422 through the bend line 24221, making it easier to bend the connecting member 24 at the bend line 24221.

[0114] In some embodiments, taking the bend line 24221 as an example, Figure 9 Another side view of the connecting member 24 according to an embodiment of this application is shown. Figure 9 As shown, the inner transition layer 2422 can be pre-bent to form a bend line 24221 in the bent area; then, as shown... Figure 9 The inner transition layer 2422 of the connecting member 24 shown unfolds to, as Figure 7 and Figure 8 In the unfolded state shown, a bend line 24221 will be left on the inner transition layer 2422 to facilitate the connection between the connecting member 24 and the tab 222 and the electrode terminal 23. Figure 6 After that, based on the positions of the bend line 24221 and the first groove 24211, it is bent as shown. Figure 5 The structure shown.

[0115] In some embodiments, if the bend line 24221 is a scribing mark, one or more scribing marks can be pre-processed on the inner transition layer 2422. For example, one or more scribing marks can be processed on the surface of the inner transition layer 2422 facing the outer transition layer 2421 to facilitate the inner transition layer 2422 bending at the bend line 24221. However, the embodiments of this application are not limited to this.

[0116] Figure 10A side view schematic diagram of the connecting member 24 in the unfolded state according to another embodiment of this application is shown, for example, Figure 10 It can be like Figures 3 to 6 One possible implementation of the unfolded state of the connecting member 24 included in any of the accompanying drawings. Figure 11 A top view of the connecting member 24 in the deployed state according to another embodiment of this application is shown, for example, Figure 11 It can be Figure 10 A top view of the connecting member 24 shown.

[0117] In some embodiments, when the connecting member 24 is in the unfolded state, if the inner transition layer 2422 is provided with a second groove 24222 recessed toward the outer transition layer 2421, and the outer transition layer 2421 is provided with a first groove 24211 recessed away from the inner transition layer 2422, then there is a gap between the second groove 24222 and the first groove 24211. Figure 10 and Figure 11 As shown, when the connecting member 24 is in the unfolded state, a second groove 24222 is provided in the inner transition layer 2422, and a first groove 24211 is provided in the outer transition layer 2421. By setting the protrusion height of the second groove 24222 to be less than the recess depth of the first groove 24211, a gap can be formed between the surface of the first groove 24211 facing the inner transition layer 2422 and the surface of the second groove 24222 facing the outer transition layer 2421. This gap can be used to reduce wrinkles and bulges in the inner transition layer 2422 when the connecting member 24 is bent.

[0118] Grooves are provided in both the inner transition layer 2422 and the outer transition layer 2421, which makes it easier to bend the transition part 242, reducing wrinkles and bulges in the inner transition layer 2422 and facilitating processing.

[0119] It should be understood that the dimensions of the second groove 24222 of the inner transition layer 2422 and the first groove 24211 of the outer transition layer 2421 can be set according to the actual application.

[0120] In some embodiments, when the connecting member 24 is in the unfolded state, the depth H1 of the first groove 24211 is greater than the depth H2 of the second groove 24222, so that there is a gap between the inner transition layer 2422 and the outer transition layer 2421.

[0121] In some embodiments, when the connecting member 24 is in the unfolded state, the depth H1 of the first groove 24211 and the depth H2 of the second groove 24222 satisfy: H2 ≤ 2 / 3H1, to increase the gap between the inner transition layer 2422 and the outer transition layer 2421, thereby ensuring that the connecting member 24 is in the unfolded state. Figure 5 When bent as shown, it effectively reduces wrinkles and bulges in the inner transition layer 2422.

[0122] It should be understood that, such as Figure 10 As shown, considering that the cross-section of the first groove 24211 can have any shape, the depth H1 of the first groove 24211 in this embodiment can refer to the maximum depth of the first groove 24211 in different regions as H1; similarly, the depth H2 of the second groove 24222 can refer to the maximum depth of the second groove 24222 in different regions as H2.

[0123] In some embodiments, such as Figure 10 and Figure 11 As shown, when the connecting member 24 is in the unfolded state, the maximum dimension W1 of the first groove 24211 along the second direction L and the maximum dimension W2 of the second groove 24222 along the second direction L satisfy: W2≤2 / 3W1, where the second direction L is the arrangement direction of the electrode terminal connection portion 243, the transition portion 242, and the tab connection portion 241 when the connecting member 24 is in the unfolded state. Because when the connecting member 24 is in such a state... Figure 5 When the bending state is shown, the circumferential length of the inner transition layer 2422 is significantly smaller than the circumferential length of the outer transition layer 2421. The maximum dimension W1 of the first groove 24211 along the second direction L is greater than the maximum dimension W2 of the second groove 24222 along the second direction L, which makes it easier for the transition part 242 to bend and effectively reduces the wrinkles and bulges of the inner transition layer 2422.

[0124] It should be understood that, such as Figure 10 and Figure 11 As shown, when the connecting member 24 is in the unfolded state, the maximum dimension W1 of the first groove 24211 along the second direction L can refer to the dimension W1 of the plane containing the opening edge of the first groove 24211 in the second direction L, wherein the opening edge of the first groove 24211 can be the starting position of the indentation of the outer transition layer 2421 of the transition portion 242; similarly, the maximum dimension W2 of the second groove 24222 along the second direction L can refer to the dimension W2 of the plane containing the opening edge of the second groove 24222 in the second direction L, wherein the opening edge of the second groove 24222 can be the starting position of the indentation of the inner transition layer 2422 of the transition portion 242.

[0125] It should be understood that the shapes of the first groove 24211 and the second groove 24222 in the embodiments of this application can be set according to actual applications. For example, the shapes of the first groove 24211 and the second groove 24222 can be the same or different. For another example, such as... Figure 10 and Figure 11 As shown, the surface of the first groove 24211 facing the second groove 24222 can be an arc or approximately an arc, and the surface of the second groove 24222 away from the first groove 24211 can also be an arc or approximately an arc, so as to facilitate the bending of the transition portion 242 and reduce stress concentration.

[0126] It should be understood that the first groove 24211 and the second groove 24222 in the embodiments of this application can be obtained by various methods. For example, the first groove 24211 and / or the second groove 24222 can be obtained by stamping to improve processing efficiency.

[0127] It should be understood that the dimensions of the transition portion 242 in this embodiment can be set according to actual applications. For example, the dimensions of the inner transition layer 2422 and the outer transition layer 2421 of the transition portion 242 can be set according to actual applications.

[0128] In some embodiments, the tab connection portion 241 is the area where the connecting member 24 is welded to the tab 222, and the electrode terminal connection portion 243 is the area where the connecting member 24 is welded to the electrode terminal 23. Along the arrangement direction of the electrode terminal connection portion 243, the transition portion 242, and the tab connection portion 241, the difference between the length of the outer transition layer 2421 and the length of the inner transition layer 2422 is greater than or equal to 0.5 mm, and less than or equal to 20 times the thickness of the inner transition layer 2422. For example... Figures 5 to 11 As shown, taking the example of an electrical connection between the tab connection portion 241 and the tab 222 achieved by welding, the tab connection portion 241 is the area of ​​the connecting member 24 that is welded to the tab 222. Similarly, taking the example of an electrical connection between the electrode terminal connection portion 243, i.e., the electrode terminal 23, achieved by welding, the electrode terminal connection portion 243 is the area of ​​the connecting member 24 that is welded to the electrode terminal 23. Therefore, the transition portion 242 is the entire area from the tab connection portion 241 to the electrode terminal connection portion 243, that is, one end of the transition portion 242 is connected to the tab connection portion 241, and the other end is connected to the electrode terminal connection portion 243.

[0129] by Figure 5 Taking the bending state shown as an example, along the arrangement direction of the electrode terminal connection portion 243, the transition portion 242, and the tab connection portion 241, the length of the outer transition layer 2421 refers to the total length from one end of it connected to the electrode terminal connection portion 243, along its bending direction, to one end of it connected to the tab connection portion 241; similarly, the length of the inner transition layer 2422 refers to the total length from one end of it connected to the electrode terminal connection portion 243, along its bending direction, including any possible local bulges, to one end of it connected to the tab connection portion 241.

[0130] Or, with Figure 6 Taking the unfolded state as an example, along the arrangement direction of the electrode terminal connection portion 243, the transition portion 242, and the tab connection portion 241, the length of the outer transition layer 2421 refers to the total length from one end of it connected to the electrode terminal connection portion 243, along its extending direction, including the provided first groove 24211, to one end of it connected to the tab connection portion 241; similarly, the length of the inner transition layer 2422 refers to the total length from one end of it connected to the electrode terminal connection portion 243, along its extending direction, including the possible provided second groove 24222 or bend line 24221, to one end of it connected to the tab connection portion 241.

[0131] It should be understood that in the embodiments of this application, the difference between the length of the outer transition layer 2421 and the length of the inner transition layer 2422 is the length of the longer outer transition layer 2421 minus the length of the shorter inner transition layer 2422, that is, the difference is greater than zero.

[0132] Therefore, by setting the difference between the length of the outer transition layer 2421 and the length of the inner transition layer 2422 to be greater than or equal to 0.5 mm, it is easier to achieve a gap between the first groove 24211 of the inner transition layer 2422 and the outer transition layer 2421, thereby reducing the bulging of the inner transition layer 2422 when the connecting member 24 is bent, and improving structural stability. At the same time, by setting the difference between the length of the outer transition layer 2421 and the length of the inner transition layer 2422 to be less than or equal to 20 times the thickness T2 of the inner transition layer 2422, the length of the outer transition layer 2421 can be limited to prevent it from being too long, and the gap between the first groove 24211 of the inner transition layer 2422 and the outer transition layer 2421 can be limited to prevent it from being too large, thereby reducing the space occupied by the transition part 242 and increasing the energy density of the battery cell 20.

[0133] In some embodiments, along the arrangement direction of the electrode terminal connection portion 243, the transition portion 242, and the tab connection portion 241, the difference between the length of the outer transition layer 2421 and the length of the inner transition layer 2422 can be any one of the following values ​​or between the following values: 0.5mm, 0.6mm, 0.8mm, 1mm, 1.3mm, 1.5mm, 1.8mm, 2mm, 2.3mm, 2.5mm, 2.8mm, 3mm, 3.3mm, 3.5mm, 3.8mm, 4mm, 4.3mm, 4.5mm, 4.8mm, 5mm, 5.3mm, 5.5mm, 5.8mm, or 6mm, etc.

[0134] The following description will use several embodiments and comparative examples as examples. Specifically, the following embodiments and comparative examples are illustrated as follows: Figures 3 to 6Taking the battery cell 20 shown as an example, in Table 1 below, "length difference" refers to the specific value of the difference between the length of the outer transition layer 2421 and the length of the inner transition layer 2422 along the arrangement direction of the electrode terminal connection portion 243, the transition portion 242, and the tab connection portion 241. Furthermore, the following embodiments and comparative examples are identical except for the value of "length difference" as shown in Table 1. For example, in the embodiments and comparative examples in Table 1, the external dimensions of each region of the outer casing of the battery cell 20 are the same; the dimensions of the main body 221 of the internal electrode assembly 22 are also the same; the bending method of the tab 222 is also the same. The material of the inner transition layer 2422 is copper, and the thickness T2 of the inner transition layer 2422 is set to 0.1 mm.

[0135] Table 1

[0136]

[0137] In Table 1 above, by setting the difference between the length of the outer transition layer 2421 and the length of the inner transition layer 2422 to be different, during the processing of the battery cell 20, the inner transition layer 2422 may bulge during the bending of the transition portion 242, which may cause the connecting member 24 to exert a squeezing effect on the electrode assembly 22 below it. In Table 1 above, "squeezing situation" indicates whether the connecting member 24 will squeeze the electrode assembly 22 below it when it is bent.

[0138] As shown in Table 1, during the processing of the battery cell 20, the smaller the difference between the length of the outer transition layer 2421 and the length of the inner transition layer 2422, the larger the bulge size of the inner transition layer 2422 will be. A larger bulge structure will cause the connecting member 24 to squeeze the electrode assembly 22, and the larger the bulge size, the greater the squeezing force of the connecting member 24 on the electrode assembly 22 below. For example, if there is a difference between the length of the outer transition layer 2421 and the length of the inner transition layer 2422, the squeezing force of the connecting member 24 on the electrode assembly 22 will be relatively smaller compared to the case where the difference between the length of the outer transition layer 2421 and the length of the inner transition layer 2422 is zero or approximately zero.

[0139] Conversely, the greater the difference between the length of the outer transition layer 2421 and the length of the inner transition layer 2422, the smaller the bulge size of the inner transition layer 2422, or even the absence of a bulge. Consequently, the pressure exerted by the connecting member 24 on the lower electrode assembly 22 is smaller, or even nonexistent. However, if the difference between the length of the outer transition layer 2421 and the length of the inner transition layer 2422 is too large, as in Comparative Example 2 in Table 1, it will affect the space occupied by the electrode assembly 22 within the battery cell 20, reducing the energy density of the battery cell 20. Furthermore, a larger outer transition layer 2421 will result in greater redundancy, potentially causing it to bulge due to pressure from other components. For example, the outer transition layer 2421 may be compressed by the support 25 or the housing 211, resulting in a bulging structure that also exerts pressure from the connecting member 24 on the lower electrode assembly 22. Therefore, the difference between the length of the outer transition layer 2421 and the length of the inner transition layer 2422 should not be set too large.

[0140] It should be understood that, in the embodiments of this application where the difference between the length of the outer transition layer 2421 and the length of the inner transition layer 2422 is small, the inner transition layer 2422 will bulge after the transition portion 242 is bent; that is, the inner transition layer 2422 has a protruding structure 24223 that protrudes in a direction away from the outer transition layer 2421. Furthermore, by adjusting the difference between the length of the outer transition layer 2421 and the length of the inner transition layer 2422, the size of the protruding structure 24223 of the inner transition layer 2422 can be adjusted accordingly.

[0141] In some embodiments, the inner transition layer 2422 has a protrusion structure 24223 protruding in a direction away from the outer transition layer 2421, and the protrusion height H of the protrusion structure 24223 is less than or equal to 5 times the thickness of the inner transition layer 2422. Figure 5 For example, when the connecting member 24 is in a bent state, the inner transition layer 2422 has a protrusion structure 24223, the protrusion height of which is H relative to the surface of other areas of the inner transition layer 2422.

[0142] When the inner transition layer 2422 has a protruding structure 24223, that is, when the protrusion height H of the protruding structure 24223 is greater than zero, by setting the protrusion height H of the protruding structure 24223 to be less than or equal to 5 times the thickness of the inner transition layer 2422, the protruding structure 24223 can be limited to be smaller, reducing the space it occupies and increasing the energy density of the battery cell 20. In addition, the smaller size of the protruding structure 24223 can reduce the pressure of the connecting member 24 on the electrode assembly 22, reduce damage to the electrode assembly 22, and improve the performance and stability of the battery cell 20.

[0143] The following description will use several embodiments and comparative examples as examples. Specifically, the following embodiments and comparative examples are illustrated as follows: Figures 3 to 6 Taking the battery cell 20 shown as an example, in Table 2 below, "height H" represents the specific value of the protrusion height H of the protrusion structure 24223 of the inner transition layer 2422 mentioned above. Furthermore, the following embodiments and comparative examples are identical except for the value of "height H" as shown in Table 2. For example, the external dimensions of each region of the outer shell of the battery cell 20 in the various embodiments and comparative examples in Table 2 are the same; the dimensions of the main body 221 of the internal electrode assembly 22 are also the same; the bending method of the tabs 222 is also the same. The material of the inner transition layer 2422 is copper, and the thickness T2 of the inner transition layer 2422 is set to 0.1 mm.

[0144] Table 2

[0145]

[0146] In Table 2 above, when the connecting member 24 is bent, the different protrusion height H of the protrusion structure 24223 of the inner transition layer 2422 can cause the connecting member 24 to exert a squeezing effect on the electrode assembly 22 below it. In Table 2, "Squeezing Condition" indicates whether the connecting member 24 will squeeze the electrode assembly 22 below it when it is bent. According to Table 2, when the connecting member 24 is bent, the smaller the protrusion height H of the protrusion structure 24223, the smaller the squeezing effect of the connecting member 24 on the electrode assembly 22 below, or even no squeezing at all. For example, in embodiments 4 and 5 in Table 2, the protrusion height H of the protrusion structure 24223 is small, and the connecting member 24 exerts no squeezing or negligible squeezing effect on the electrode assembly 22 below.

[0147] Conversely, when the connecting member 24 is bent, the larger the protrusion height H of the protrusion structure 24223, the more the larger the size of the protrusion structure 24223 will cause the connecting member 24 to compress the electrode assembly 22. Furthermore, the larger the size of the protrusion structure 24223, the greater the compressive force exerted by the connecting member 24 on the electrode assembly 22 below, which can lead to damage to the electrode assembly 22 and affect its performance. In addition, the larger the protrusion height H of the protrusion structure 24223, the larger the space occupied by the connecting member 24 in the first direction Z will be. Therefore, the protrusion height H of the protrusion structure 24223 of the inner transition layer 2422 should not be too large.

[0148] In some embodiments, when the transition portion 242 has a multi-layer structure, the thicknesses of the different structural layers can be the same or different. For example, in embodiments of this application, the thickness T1 of the outer transition layer 2421 and the thickness T2 of the inner transition layer 2422 are typically set to be equal to facilitate processing.

[0149] In some embodiments, the thickness T1 of the outer transition layer 2421 can be related to the material of the outer transition layer 2421, and similarly, the thickness T2 of the inner transition layer 2422 can be related to the material of the inner transition layer 2422.

[0150] In some embodiments, when the outer transition layer 2421 is made of copper, the thickness T1 of the outer transition layer 2421 typically satisfies 0.05mm ≤ T1 ≤ 0.2mm; similarly, when the inner transition layer 2422 is made of copper, the thickness T2 of the inner transition layer 2422 typically satisfies 0.05mm ≤ T2 ≤ 0.2mm. Appropriately increasing the thicknesses T1 and T2 can improve the structural strength of the transition portion 242 and reduce the risk of fracture in each layer; at the same time, limiting the thicknesses T1 and T2 to be not too large facilitates bending of the transition portion 242, reduces bending difficulty, and improves processing efficiency.

[0151] In some embodiments, when the material of the outer transition layer 2421 is copper, the thickness T1 of the outer transition layer 2421 can also be any of the following values ​​or between any of the following values: 0.05mm, 0.08mm, 0.1mm, 0.12mm, 0.13mm, 0.15mm, 0.16mm, 0.18mm or 0.2mm.

[0152] In some embodiments, when the material of the inner transition layer 2422 is copper, the thickness T2 of the inner transition layer 2422 can also be any of the following values ​​or between any of the following values: 0.05mm, 0.08mm, 0.1mm, 0.12mm, 0.13mm, 0.15mm, 0.16mm, 0.18mm or 0.2mm.

[0153] In some embodiments, when the outer transition layer 2421 is made of aluminum, the thickness T1 of the outer transition layer 2421 typically satisfies 0.05mm ≤ T1 ≤ 0.3mm; similarly, when the inner transition layer 2422 is made of aluminum, the thickness T2 of the inner transition layer 2422 typically satisfies 0.05mm ≤ T2 ≤ 0.3mm. Appropriately increasing the thicknesses T1 and T2 can improve the structural strength of the transition portion 242 and reduce the risk of fracture in each layer; at the same time, limiting the thicknesses T1 and T2 to be not too large facilitates bending of the transition portion 242, reduces bending difficulty, and improves processing efficiency.

[0154] In some embodiments, when the material of the outer transition layer 2421 is aluminum, the thickness T1 of the outer transition layer 2421 can also be any of the following values ​​or between any of the following values: 0.05mm, 0.08mm, 0.1mm, 0.13mm, 0.15mm, 0.18mm, 0.2mm, 0.23mm, 0.25mm, 0.28mm or 0.3mm.

[0155] In some embodiments, when the material of the inner transition layer 2422 is aluminum, the thickness T2 of the inner transition layer 2422 can also be any of the following values ​​or between any of the following values: 0.05mm, 0.08mm, 0.1mm, 0.13mm, 0.15mm, 0.18mm, 0.2mm, 0.23mm, 0.25mm, 0.28mm or 0.3mm.

[0156] It should be understood that, such as Figure 10 and Figure 11 As shown in the accompanying drawings of this application embodiment, the thickness T1 of the outer transition layer 2421 is equal to that of the first structural layer 2411, and the thickness T2 of the inner transition layer 2422 is equal to that of the second structural layer 2412, but the embodiments of this application are not limited thereto.

[0157] In some embodiments, the total thickness T0 of the transition portion 242 typically satisfies 0.1mm≤T0≤0.6mm, which can improve the structural strength of the transition portion 242 and reduce the risk of breakage; at the same time, limiting the thickness T0 to not be too large can also facilitate bending the transition portion 242, reduce bending difficulty, and improve processing efficiency.

[0158] It should be understood that the total thickness T0 of the transition portion 242 in this embodiment is equal to the sum of the thicknesses of each structural layer. For example, as Figure 10 and Figure 11 As shown, taking the transition portion 242 as an example that includes only the outer transition layer 2421 and the inner transition layer 2422, the total thickness T0 of the transition portion 242 is equal to the sum of the thickness T1 of the outer transition layer 2421 and the thickness T2 of the inner transition layer 2422.

[0159] In some embodiments, the total thickness T0 of the transition portion 242 may be any of the following values ​​or between any of the following values: 0.1mm, 0.13mm, 0.15mm, 0.18mm, 0.2mm, 0.23mm, 0.25mm, 0.28mm, 0.3mm, 0.33mm, 0.35mm, 0.38mm, 0.4mm, 0.43mm, 0.45mm, 0.48mm, 0.5mm, 0.53mm, 0.55mm, 0.58mm, or 0.6mm.

[0160] It should be understood that, in the above embodiments, when the connecting member 24 is in the unfolded state, the maximum value of the distance between the surface of the inner transition layer 2422 facing the outer transition layer 2421 and the surface of the outer transition layer 2421 facing the outer transition layer 2421 along the thickness direction of the transition portion 242 can be set according to the actual application. For example, the size of the gap between the inner transition layer 2422 and the outer transition layer 2421 can be determined according to the thickness T1 of the outer transition layer 2421 and the thickness T2 of the inner transition layer 2422 to reduce wrinkles and bulges in the inner transition layer 2422, thereby improving structural stability and reliability.

[0161] Figure 12 This illustration shows a top view of the connecting member 24 in an unfolded state according to another embodiment of this application. For example, Figure 12 It can be like Figures 3 to 6 One possible implementation of the unfolded state of the connecting member 24 included in any of the accompanying drawings.

[0162] In some embodiments, the connecting member 24 is provided with an opening 244, at least a portion of which is located in the transition portion 242. On the one hand, the opening 244 can reduce the current carrying capacity of the connecting member 24 in the area surrounding the opening 244, thereby facilitating the melting of the connecting member 24 in the area where the opening 244 is located when a short circuit occurs in the battery cell 20; on the other hand, the fact that at least a portion of the opening 244 is located in the transition portion 242 can weaken the structural strength of the transition portion 242, facilitating the bending of the transition portion 242.

[0163] It should be understood that, in this embodiment, the opening 244 is a through hole extending through the thickness region of the connecting member 24. The position and shape of the opening 244 can be configured according to the actual application. For example, as Figure 12 As shown, the opening 244 can be circular, elliptical, or U-shaped; for example, the opening 244 can be located at the edge of the connecting member 24, or the opening 244 can also be located in the middle area of ​​the connecting member 24, and the embodiments of this application are not limited thereto.

[0164] In some embodiments, the connecting member 24 may be provided with one or more openings 244 to balance the current carrying capacity of the connecting member 24 during normal use and the melting speed during a short circuit.

[0165] In some embodiments, openings 244 are respectively provided on both sides of the transition portion 242 along the third direction Y. The third direction Y is perpendicular to the first direction Z and the second direction L. The second direction L is the arrangement direction of the electrode terminal connection portion 243, the transition portion 242, and the tab connection portion 241 when the connecting member 24 is in the unfolded state. Considering that the transition portion 242 is located in the middle position of the connecting member 24 along the second direction L, by providing an opening 244 at each end of the transition portion 242 in the third direction Y, the transition portion 242 can be approximately symmetrical, and the connecting member 24 can also be approximately symmetrical. This can balance the current carrying capacity of different regions of the connecting member 24, thereby improving the structural stability of the connecting member 24.

[0166] It should be understood that the size of the opening 244 in the embodiments of this application can be set according to actual applications. For example, when the connecting member 24 includes multiple openings 244, the multiple openings 244 can have the same size to facilitate processing, or they can be different to apply to different application scenarios.

[0167] In some embodiments, when the connecting member 24 is in the unfolded state, the size W3 of the opening 244 along the second direction L is greater than or equal to 10 mm, so as to effectively determine the weak position of the connecting member 24 when overcurrent occurs, so that the connecting member 24 will melt at the weak position when the battery cell 20 is short-circuited.

[0168] It should be understood that, such as Figures 7 to 12 As shown, the electrode terminal connection portion 243 of this embodiment is used for electrical connection with the electrode terminal 23. For example, taking the electrical connection between the electrode terminal connection portion 243 and the electrode terminal 23 as an example of achieving electrical connection by welding, the electrode terminal connection portion 243 may include a welding area 2433, the size of which can be set according to the actual application. The welding method between the electrode terminal connection portion 243 and the electrode terminal 23 can be set according to the actual application; for example, they can be electrically connected by laser welding.

[0169] In some embodiments, such as Figures 7 to 12 As shown, taking the connecting member 24 in the unfolded state as an example, the area of ​​the orthographic projection of the welding area 2433 on the plane perpendicular to the thickness direction of the connecting member 24 is S1; taking the bending area of ​​the transition portion 242 of the connecting member 24 as the boundary, along the second direction L, the connecting member 24 can be divided into two regions, wherein the total area of ​​the side region where the welding area 2433 is located is S2. Then S1 and S2 usually satisfy: S1≥1 / 5S2, so as to improve the welding stability and reliability between the welding area 2433 and the electrode terminal 23.

[0170] It should be understood that when the electrode terminal connection portion 243 of the present application embodiment is provided with at least a partial opening 244, the area S2 of the orthographic projection of the electrode terminal connection portion 243 on the plane perpendicular to the thickness direction of the connecting member 24 may not include the area of ​​the partial opening 244, but the present application embodiment is not limited to this.

[0171] According to some embodiments of this application, this application also provides a battery device 10, including a battery cell 20 as described in any of the above embodiments.

[0172] According to some embodiments of this application, this application also provides an electrical device including the battery device 10 described in any of the above embodiments, and the battery device 10 is used to provide electrical energy to the electrical device.

[0173] The electrical equipment can be any of the aforementioned devices or systems that utilize battery devices.

[0174] In some embodiments, the electrical equipment includes a battery device 10 and an electrical load. The electrical equipment may be, but is not limited to, power equipment (such as electric vehicles, electric boats, spacecraft), electronic devices (such as mobile phones, tablets, laptops, bionic machines, digital cameras, electric toys, etc.), wearable devices (such as watches, bracelets, VR glasses, etc.), energy storage power stations, etc.

[0175] According to some embodiments of this application, see Figures 5 to 12 This application provides a battery cell 20, including: an electrode assembly 22, including a main body 221 and a tab 222; an electrode terminal 23; and a connecting member 24, the connecting member 24 including a tab connecting portion 241, a transition portion 242, and an electrode terminal connecting portion 243, the tab connecting portion 241 being used to connect to the tab 222, and the electrode terminal connecting portion 243 being used to connect to the electrode terminal 23; the electrode terminal connecting portion 243 and the tab connecting portion 241 are at least partially stacked along a first direction Z, the first direction Z being the arrangement of the electrode terminal 23 and the electrode assembly 22. Direction; the transition portion 242 is connected to the electrode terminal connection portion 243 and the tab connection portion 241 respectively, and the connecting member 24 is bent in the transition portion 242; the transition portion 242 includes an inner transition layer 2422 and an outer transition layer 2421 stacked along the thickness direction of the transition portion 242; when the connecting member 24 is in the unfolded state, the outer transition layer 2421 has a first groove 24211 recessed away from the inner transition layer 2422, and there is a gap between the inner transition layer 2422 and the first groove 24211 along the thickness direction of the transition portion 242.

[0176] When the connecting member 24 is in the unfolded state, the inner transition layer 2422 has a second groove 24222 recessed toward the outer transition layer 2421, and there is a gap between the first groove 24211 and the second groove 24222. When the connecting member 24 is in the unfolded state, the depth H1 of the first groove 24211 and the depth H2 of the second groove 24222 satisfy: H2≤2 / 3H1; and / or, when the connecting member 24 is in the unfolded state, the maximum dimension W1 of the first groove 24211 along the second direction L and the maximum dimension W2 of the second groove 24222 along the second direction L satisfy: W2≤2 / 3W1, where the second direction L is the arrangement direction of the electrode terminal connection portion 243, the transition portion 242, and the tab connection portion 241 when the connecting member 24 is in the unfolded state.

[0177] The tab connection portion 241 is the area where the connecting member 24 is welded to the tab 222, and the electrode terminal connection portion 243 is the area where the connecting member 24 is welded to the electrode terminal 23. Along the arrangement direction of the electrode terminal connection portion 243, the transition portion 242, and the tab connection portion 241, the difference between the length of the outer transition layer 2421 and the length of the inner transition layer 2422 is greater than or equal to 0.5 mm, and less than or equal to 20 times the thickness of the inner transition layer 2422. The inner transition layer 2422 has a protruding structure 24223 protruding in a direction away from the outer transition layer 2421, and the protrusion height of the protruding structure 24223 is less than or equal to 5 times the thickness of the inner transition layer 2422.

[0178] The electrode connector 241 includes a first structural layer 2411 and a second structural layer 2412 stacked along a first direction Z. The first structural layer 2411 and the outer transition layer 2421 are integrally formed, and the second structural layer 2412 and the inner transition layer 2422 are integrally formed. Along the first direction Z, the electrode 222 is located between the first structural layer 2411 and the second structural layer 2412. The electrode terminal connector 243 includes a third structural layer 2431 and a fourth structural layer 2432 stacked along the first direction Z. The third structural layer 2431 and the outer transition layer 2421 are integrally formed, and the fourth structural layer 2432 and the inner transition layer 2422 are integrally formed. Along the first direction Z, the third structural layer 2431 is located between the electrode terminal 23 and the fourth structural layer 2432.

[0179] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized by, The electrode assembly (22) comprises a main body portion (221) and a tab (222); the electrode terminal (23); the connecting member (24) comprises a tab connecting portion (241) for connecting with the tab (222), an electrode terminal connecting portion (243) for connecting with the electrode terminal (23); the electrode terminal connecting portion (243) and the tab connecting portion (241) are at least partially stacked along a first direction, which is the arrangement direction of the electrode terminal (23) and the electrode assembly (22); the transition portion (242) connects the electrode terminal connecting portion (243) and the tab connecting portion (241) respectively, and the connecting member (24) is bent at the transition portion (242); the transition portion (242) comprises an inner transition layer (2422) and an outer transition layer (2421) stacked along the thickness direction of the transition portion (242); in the case that the connecting member (24) is in an unfolded state, the outer transition layer (2421) has a first groove (24211) recessed away from the inner transition layer (2422), and there is a gap between the inner transition layer (2422) and the first groove (24211) along the thickness direction of the transition portion (242). In the case that the connecting member (24) is in an unfolded state, the inner transition layer (2422) has a second groove (24222) recessed toward the outer transition layer (2421), and there is a gap between the second groove (24222) and the first groove (24211). In the case that the connecting member (24) is in an unfolded state, the depth H1 of the first groove (24211) and the depth H2 of the second groove (24222) satisfy: H2≤2 / 3H1; and / or, In the case that the connecting member (24) is in an unfolded state, the maximum size W1 of the first groove (24211) along a second direction and the maximum size W2 of the second groove (24222) along the second direction satisfy: W2≤2 / 3W1, the second direction being the arrangement direction of the electrode terminal connecting portion (243), the transition portion (242) and the tab connecting portion (241) in the case that the connecting member (24) is in an unfolded state.

2. The battery cell of claim 1, wherein, The tab connecting portion (241) is the region of the connecting member (24) welded with the tab (222), and the electrode terminal connecting portion (243) is the region of the connecting member (24) welded with the electrode terminal (23), 3. The battery cell of claim 2, wherein, ​ ​ 4. The battery cell of claim 1, wherein, ​ A difference between a length of the outer transition layer (2421) and a length of the inner transition layer (2422) in an arrangement direction of the electrode terminal connecting portion (243), the transition portion (242), and the tab connecting portion (241) is greater than or equal to 0.5 mm and less than or equal to 20 times a thickness of the inner transition layer (2422).

5. The battery cell of claim 4, wherein, The inner transition layer (2422) has a protruding structure (24223) protruding toward a direction away from the outer transition layer (2421), and a protruding height of the protruding structure (24223) is less than or equal to 5 times a thickness of the inner transition layer (2422).

6. The battery cell of claim 1, wherein, The tab connecting portion (241) includes a first structure layer (2411) and a second structure layer (2412) stacked in the first direction, the first structure layer (2411) and the outer transition layer (2421) are an integral structure, and the second structure layer (2412) and the inner transition layer (2422) are an integral structure.

7. The battery cell of claim 6, wherein, In the first direction, the tab (222) is located between the first structure layer (2411) and the second structure layer (2412).

8. The battery cell of claim 1, wherein, The electrode terminal connecting portion (243) includes a third structure layer (2431) and a fourth structure layer (2432) stacked in the first direction, the third structure layer (2431) and the outer transition layer (2421) are an integral structure, and the fourth structure layer (2432) and the inner transition layer (2422) are an integral structure.

9. The battery cell of claim 8, wherein, In the first direction, the third structure layer (2431) is located between the electrode terminal (23) and the fourth structure layer (2432).

10. The battery cell of claim 9, wherein, The third structure layer (2431) and the fourth structure layer (2432) are welded or connected by conductive glue.

11. The battery cell of any one of claims 1 to 10, wherein, The connecting member (24) is provided with an opening (244), at least a partial region of the opening (244) is located in the transition portion (242).

12. The battery cell of claim 11, wherein, Both sides of the transition portion (242) in a third direction are respectively provided with the opening (244), the third direction is perpendicular to the first direction and a second direction, the second direction is an arrangement direction of the electrode terminal connecting portion (243), the transition portion (242), and the tab connecting portion (241) when the connecting member (24) is in an unfolded state.

13. The battery cell of claim 12, wherein, In the unfolded state of the connecting member (24), a size of the opening (244) in the second direction is greater than or equal to 10 mm.

14. The battery cell of any one of claims 1 to 10, wherein, The tab (222) includes a converging portion (2221) and a fixing portion (2222), the converging portion (2221) is bent relative to the fixing portion (2222), the converging portion (2221) is connected to the main body portion (221), and the fixing portion (2222) is connected to the tab connecting portion (241).

15. A battery device characterized by comprising: Comprise: A plurality of battery cells, the battery cells being the battery cell as claimed in any one of claims 1 to 14.

16. An electrical device, characterized by Comprise: A battery device including the battery cell as claimed in any one of claims 1 to 14, the battery device being used to power the electrical device.

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