Battery cell, battery, and power consumption device

Abstract

The embodiments of the present application provide a battery cell, a battery, and a power consumption device. The battery cell includes an electrode assembly, a case, an electrode terminal, and a current collecting component. The electrode assembly includes a first tab. The case is used to house the electrode assembly. The electrode terminal is installed in the case, and the electrode terminal includes a first recess and a connecting portion located at the bottom of the first recess. The current collecting component is connected to the first tab and welded to the connecting portion. By opening the first recess in the electrode terminal and reducing the thickness of the connecting portion, the welding power required to weld the connecting portion to the current collecting component is reduced, reducing heat generation and the risk of burning other components, thereby improving safety.

Description

Technical Field

[0001] (Cross - reference to related applications) This application claims the priority of an application filed on August 23, 2021, with the invention title "Battery Cell, Its Manufacturing Method and Manufacturing System, Battery and Power - consuming Device" and the international application number PCT / CN2021 / 114156. All of the content of this application is incorporated herein by reference.

[0002] This application relates to the field of battery technology, and more specifically, to battery cells, batteries, and power - consuming devices.

Background Art

[0003] Battery cells are widely applied in electronic devices such as mobile phones, notebook computers, battery vehicles, electric vehicles, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and electric tools. Battery cells may include nickel - cadmium battery cells, nickel - hydrogen battery cells, lithium - ion battery cells, and secondary alkaline zinc - manganese battery cells, etc.

[0004] In the development of battery technology, how to improve the safety of battery cells is one of the research directions of battery technology.

Summary of the Invention

[0005] This application provides a battery cell, a battery, and a power - consuming device, which can improve the safety of the battery cell.

[0006] According to a first aspect, an embodiment of this application provides a battery cell including an electrode assembly, a case, an electrode terminal, and a current - collecting component. The electrode assembly includes a first tab. The case is used to accommodate the electrode assembly. The electrode terminal is installed on the case and includes a first recess and a connection part located at the bottom of the first recess. The current - collecting component is connected to the first tab and welded to the connection part.

[0007] In the above technical solution, a first recess is formed in the electrode terminal to reduce the thickness of the connection part, thereby reducing the welding power required for welding the connection part and the current collecting component, reducing heat generation, reducing the risk of other components being burned out, and improving safety.

[0008] In some embodiments, the current collecting component is welded to the connection part to form a first welding part. In the thickness direction of the connection part, the first welding part extends at least into the interior of the current collecting component from the side away from the current collecting component of the connection part.

[0009] In the above technical solution, the first welding part extends from the connection part into the interior of the current collecting component, connects the current collecting component and the connection part, reduces the contact resistance between the current collecting component and the electrode terminal, and improves the overcurrent capacity.

[0010] In some embodiments, in the thickness direction of the connection part, the first welding part does not protrude beyond the surface of the current collecting component away from the connection part.

[0011] In the above technical solution, the first welding part and the surface of the current collecting component away from the connection part are spaced apart by a predetermined distance to avoid the current collecting component from melting and falling off, reduce the risk of metal particles being generated on the surface of the current collecting component away from the connection part, and improve safety.

[0012] In some embodiments, the case includes a cylindrical body and a lid connected to the cylindrical body. The cylindrical body is installed to surround the outer periphery of the electrode assembly. The lid is provided with an electrode lead-out hole, and the electrode terminal is attached to the electrode lead-out hole. Both the first welding part and the lid are annular. The outer diameter of the lid is D0, and the inner diameter of the first welding part is D1. D1 and D0 satisfy 0.1 ≦ D1 / D0 ≦ 0.6.

[0013] D0 has a positive correlation with the diameter of the electrode assembly. The larger D0 is, the higher the capacity of the electrode assembly, and the higher the requirements for the battery cell with respect to the overcurrent area of the first welding part. The smaller D1 is, the smaller the perimeter of the first welding part and the smaller the overcurrent area of the first welding part. If D1 / D0 is too small, since D0 is large and D1 is small, the overcurrent area of the first welding part is insufficient, the heat generation of the first welding part during charge and discharge is relatively large, and it is difficult to meet the requirements of the battery cell for the overcurrent capacity and temperature rise during rapid charging.

[0014] The larger D1 is, the larger the size of the electrode lead-out hole and the smaller the area of the cover body. Similarly, the smaller D0 is, the smaller the area of the cover body. If D1 / D0 is too large, since D0 is small and D1 is large, it is likely to cause the cover body to deform when the battery cell vibrates, causing safety concerns. The cover body can be connected to the bus bar member as one output pole of the battery cell. If D1 / D0 is too large, the connection area between the cover body and the bus bar member is small, the overcurrent area between the cover body and the bus bar member is insufficient, the heat generation at the connection point between the cover body and the bus bar member is high, and it is difficult to meet the requirements of the battery cell for the overcurrent capacity and temperature rise during rapid charging.

[0015] The above technical solution sets 0.1 ≦ D1 / D0 ≦ 0.6 to meet the requirements of the battery cell for the overcurrent capacity and temperature rise and improve the safety of the battery cell.

[0016] In some embodiments, the first welding part has a non-closed structure, and the central angle α of the first welding part is 180° to 330°.

[0017] α has a positive correlation with the overcurrent area of the first welding part. The smaller α is, the smaller the overcurrent area of the first welding part is, and the higher the heat generation is when the current flows through the first welding part. The above technical solution limits α to 180° to 330°, so that the first welding part can meet the requirements of the battery cell for overcurrent capacity and temperature rise. The first welding part has a non-closed structure, and the unwelded area between both ends along the circumferential direction of the first welding part can release welding stress and reduce stress concentration.

[0018] In some embodiments, the first welding part has a closed structure, which increases the welding area and improves the welding strength and overcurrent capacity of the first welding part.

[0019] In some embodiments, 0.2 ≤ D1 / D0 ≤ 0.4.

[0020] In some embodiments, D1 is 5 mm to 14 mm, which can meet the requirements of the battery cell for overcurrent capacity and temperature rise.

[0021] In some embodiments, the cover body and the cylinder body are integrally formed, so that the connection process between the cover body and the cylinder body can be omitted. When the cover body and the cylinder body are electrically connected to the positive electrode or the negative electrode of the electrode assembly, since the connection part between the cover body and the cylinder body has an integral structure, the resistance of the connection part between the cover body and the cylinder body is relatively small, thereby enhancing the overcurrent capacity. The cover body may be used to connect to an external component (for example, a bus bar member). When the battery cell is subjected to an external impact, the external component may pull the cover body and a force may act on the connection part between the cover body and the cylinder body. The above technical solution improves the strength of the connection part between the cover body and the cylinder body by installing the cover body and the cylinder body integrally, and reduces the risk of the connection between the cover body and the cylinder body failing.

[0022] In some embodiments, in the thickness direction of the connection part, the size of the first welding part is h, and the thickness of the area for welding to the current collecting component of the connection part is d0. d0 and h satisfy 1 < h / d0 ≤ 1.5.

[0023] When h / d0 ≤ 1, the penetration of the first weld is relatively small. Since the entire first weld is formed in the connection part, it causes dummy welding, and it is difficult for the first weld to effectively connect the current collecting component and the connection part. When d0 is constant, the larger h is, the greater the power required for welding, and the higher the heat generation during the welding process. If h is too large, the high temperature caused by welding is likely to damage the components around the electrode terminal, causing safety concerns.

[0024] The above technical solution sets 1 < h / d0 ≤ 1.5. On the premise of ensuring the connection between the current collecting component and the connection part, it reduces the welding heat generation and the welding difficulty.

[0025] In some embodiments, the thickness of the region for welding to the connection part of the current collecting component is d1, and d0 and d1 satisfy 0.5 ≤ d1 / d0 ≤ 1.2.

[0026] When d0 is constant, the smaller d1 is, the easier it is for the current collecting component to melt and fall off during the welding process, and the easier it is for the high-temperature particles caused by welding to fall into the battery cell. The larger d1 is, the larger the space and weight occupied by the current collecting component, and the lower the energy density of the battery cell.

[0027] The above technical solution sets 0.5 ≤ d1 / d0 ≤ 1.2 to reduce the risk of the current collecting component melting and falling off and reduce the loss of the energy density of the battery cell.

[0028] In some embodiments, d0 is 0.4 mm to 1.2 mm, which meets the requirements of the battery cell for overcurrent capacity and temperature rise, reduces the welding heat generation, and improves the safety.

[0029] In some embodiments, at least a part of the first tab is located on the side away from the electrode terminal of the current collecting component and is supported by the current collecting component.

[0030] In the above technical solution, the first tab can support the current collecting component so that the current collecting component is bonded to the connection part. When the battery cell is vibrating, the first tab can reduce the force applied to the first welding part by restricting the movement of the current collecting component relative to the connection part, and can reduce the risk of the first welding part being torn. When welding the connection part and the current collecting component, the first tab can reduce the relative displacement generated between the current collecting component and the connection part during the welding process by supporting the current collecting component, and can reduce the risk of dummy welding.

[0031] In some embodiments, the first portion of the first tab is located on the side away from the first recess of the connection part and is used to support the portion of the current collecting component facing the connection part.

[0032] In the above technical solution, the first portion can support the portion of the current collecting component facing the connection part so as to make the current collecting component adhere closely to the connection part and reduce the risk of dummy welding. During the welding process, the first portion can also limit the deformation of the current collecting component and improve the shape of the current collecting component.

[0033] In some embodiments, the first portion is welded to the current collecting component to form a second welding part.

[0034] In the above technical solution, the second welding part can reduce the contact resistance between the current collecting component and the first tab and improve the overcurrent capacity. The second welding part is close to the connection part, and the resistance can be reduced and the overcurrent capacity can be improved by reducing the conductive path between the connection part and the second welding part.

[0035] In some embodiments, the second portion of the first tab surrounds the outer periphery of the first portion and is used to support the area of the current collecting component that does not face the connection part.

[0036] In the above technical solution, by installing the second part, the area of the region supporting the current collecting component of the first tab is increased, the supporting effect of the first tab is improved, the pressure between the first tab and the current collecting component is reduced, and the risk of the first tab being crushed can be reduced.

[0037] In some embodiments, the second part is welded to the current collecting component to form a third welding part.

[0038] In the above technical solution, the third welding part can reduce the contact resistance between the current collecting component and the second part and improve the overcurrent capacity.

[0039] In some embodiments, the side of the current collecting component facing the first tab has a convex portion, and the convex portion is welded to the second part to form a third welding part.

[0040] In the above technical solution, the convex portion can be better attached to the second part, and the risk of welding defects can be reduced.

[0041] In some embodiments, the first tab is installed around the central axis of the electrode assembly, and the cross-section perpendicular to the central axis of the first tab is an annular shape. The outer radius of the first tab is R, and the minimum pitch between the third welding part and the central axis in the radial direction of the first tab is D2, and both satisfy 0.2 ≦ D2 / R ≦ 0.8.

[0042] R has a positive correlation with the diameter of the electrode assembly. The larger R is, the larger the current by the electrode assembly is, and the higher the requirements for the battery cell for the overcurrent area are. The part close to the central axis of the current collecting component may also be used for welding to the connecting part. The smaller D2 is, the smaller the area where the current collecting component can be welded to the connecting part is, and the smaller the overcurrent area between the current collecting component and the connecting part is. If D2 / R is too small, since D2 is small and R is large, the overcurrent area between the current collecting component and the connecting part is insufficient, and the heat generation at the welding location between the current collecting component and the connecting part during charge and discharge is relatively large, making it difficult to meet the requirements of the battery cell for the overcurrent capacity and temperature rise during rapid charging.

[0043] The first tab includes a plurality of tab layers. The larger D2 is, the more outer the tab layer directly connected to the third weld is. If D2 is too large, the number of tab layers connected to the third weld is small, and the pitch between the third weld and the innermost tab layer is too large, resulting in a large difference between the current path between the outermost tab layer and the electrode terminal and the current path between the innermost tab layer and the electrode terminal. This causes the current density of the first electrode plate to be non-uniform and increases the internal resistance.

[0044] The above technical solution limits D2 / R to 0.2 to 0.8, reduces the difference in the current paths between different positions of the first tab and the electrode terminal, improves the uniformity of the current density of the first electrode plate of the electrode assembly, reduces the internal resistance, and meets the requirements of the battery cell for overcurrent capacity and temperature rise.

[0045] In some embodiments, D2 and R satisfy 0.2 ≤ D2 / R ≤ 0.5.

[0046] In some embodiments, D2 is 3.5 mm to 10 mm, reducing the internal resistance of the electrode assembly and meeting the requirements of the battery cell for overcurrent capacity and temperature rise.

[0047] In some embodiments, the diameter of the current collector component is D3, the diameter of the first tab is D4, and D3 is smaller than D4.

[0048] In the above technical solution, the current collector component has a relatively small diameter, saving the space and weight occupied by the current collector component and increasing the energy density of the battery cell.

[0049] In some embodiments, D3 and D4 satisfy 0.75 ≤ D3 / D4 ≤ 0.97.

[0050] When D4 is constant, if D3 is too small, the distance between the outer part of the first tab and the current collecting component is too large, the conductive path between the outer part of the first tab and the current collecting component is too long, the internal resistance of the electrode assembly is large, which will affect the performance of the battery cell. The above technical solution sets D3 / D4≥0.75 to reduce the internal resistance of the electrode assembly and improve the charge and discharge performance of the battery cell.

[0051] When D4 is constant, if D3 is too large, due to assembly errors, the coaxiality between the current collecting component and the electrode assembly will vary, causing the current collecting component to protrude from the outer peripheral surface of the electrode assembly, making it difficult to incorporate the current collecting component and the electrode assembly into the case, which will affect the assembly efficiency and the superiority of the product.

[0052] When D4 is constant, if D3 is too large, due to assembly errors, the coaxiality between the current collecting component and the electrode assembly will vary, causing the current collecting component to protrude from the outer peripheral surface of the electrode assembly, making it difficult to incorporate the current collecting component and the electrode assembly into the case, which will affect the assembly efficiency and the superiority of the product. The above technical solution sets D3 / D4≤0.97 to reduce the risk of the current collecting component protruding from the outer peripheral surface of the electrode assembly due to errors, and improve the assembly efficiency and the superiority of the product.

[0053] In some embodiments, D3 is 35 mm to 44 mm. By limiting D3 to 35 mm to 44 mm, the internal resistance of the electrode assembly can be reduced, the charge and discharge performance of the battery cell can be improved, and the risk of the current collecting component protruding from the outer peripheral surface of the electrode assembly due to errors can be reduced.

[0054] In some embodiments, the connecting portion is provided with a concave groove that recesses along the direction from the first outer surface of the connecting portion towards the electrode assembly, and the first welding portion extends from the bottom wall of the concave groove to at least the inside of the current collecting component.

[0055] In the production process of a battery cell, it is necessary to fit an external device to the connection part. The surface of the first welding part has unevenness. When the external device is pressed against the first welding part, the external device is easily damaged by pressure from the first welding part. The above technical solution forms a gap between the first outer surface and the bottom wall of the concave groove by installing the concave groove. In this way, the first outer surface can be used to separate the external device from the first welding part and support the external device to reduce the risk of the external device being damaged by pressure.

[0056] In some embodiments, the case includes a cylindrical body and a cover body connected to the cylindrical body. The cylindrical body is installed to surround the outer periphery of the electrode assembly. The cover body is provided with an electrode lead-out hole, and the electrode terminal is attached to the electrode lead-out hole. The electrode terminal includes a terminal body, and the terminal body includes a columnar part, a first stopper part, and a second stopper part. At least a part of the columnar part is located within the electrode lead-out hole. The first recess is provided in the columnar part. Both the first stopper part and the second stopper part are connected to the outer side wall of the columnar part and protrude from the outer side wall of the columnar part. The first stopper part and the second stopper part are respectively provided on the outer side and the inner side of the cover body and are used to sandwich a part of the cover body.

[0057] In the above technical solution, the first stopper part and the second stopper part sandwich a part of the cover body from both sides to fix the terminal body to the cover body.

[0058] In some embodiments, the terminal body has a second outer surface, and the first recess is recessed from the second outer surface along the direction towards the electrode assembly to the first outer surface of the connection part.

[0059] In some embodiments, the electrode terminal further includes a seal plate connected to the terminal body and sealing the opening of the first recess.

[0060] In the above technical solution, the seal plate can protect the connection part from the outside, reduce external impurities entering the first recess, reduce the risk of the connection part being damaged by external impurities, and improve the sealing performance of the battery cell.

[0061] In some embodiments, the electrode assembly further includes a second tab having a polarity opposite to that of the first tab, and the second tab is disposed around the central axis of the electrode assembly. The first tab is provided at an end facing the electrode terminal of the electrode assembly, the second tab is provided at an end away from the electrode terminal of the electrode assembly, and the second tab is electrically connected to the case.

[0062] In the above technical solution, the case itself serves as one output electrode of the battery cell, thereby omitting one conventional electrode terminal and simplifying the structure of the battery cell. When assembling a plurality of battery cells into a group, the case may be electrically connected to the bus bar member. In this way, not only can the overcurrent area be increased, but also the structural design of the bus bar member can be made more flexible.

[0063] In some embodiments, the second tab is a negative tab, and the base material of the case is steel. The steel case is less likely to be corroded by the electrolyte in the low potential state.

[0064] In some embodiments, an end of the case away from the electrode terminal has an opening, and the battery cell further includes a cover plate for sealing the opening.

[0065] According to a second aspect, an embodiment of the present application provides a battery, which includes a battery cell of any one of the embodiments of the plurality of first aspects.

[0066] According to a third aspect, an embodiment of the present application provides a power consumption device, which includes the battery of the second aspect for providing electrical energy.

Brief Description of the Drawings

[0067] To more clearly illustrate the technical solutions of the embodiments of this application, the following briefly introduces the drawings that need to be used in the embodiments of this application. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, based on these drawings, other drawings can be obtained without creative efforts.

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[0068] In the drawings, the drawings are not drawn to actual scale.

Mode for Carrying Out the Invention

[0069] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the following clearly describes the technical solutions in the embodiments of the present application while combining the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts fall within the protection scope of the present application.

[0070] Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as commonly understood by those skilled in the art belonging to the technical field of the present application. In the present application, the terms used in the description of the application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The terms "including" and "having" and any variations thereof in the description of the specification, claims and the above drawings of the present application are intended to cover non-exclusive "including". The terms "first", "second", etc. in the description of the specification, claims or the above drawings of the present application are not for describing a specific order or a primary-secondary relationship, but for distinguishing different objects.

[0071] As used herein, the term "example" means that the specific features, structures, or characteristics described in connection with the examples may be included in at least one example of the present application. The appearance of this phrase at each position in the specification does not necessarily refer to the same example, nor is it an independent or alternative example that is mutually exclusive with other examples.

[0072] In the description of the present application, unless otherwise specifically defined or limited, the terms "attachment", "connection", "connection", and "attachment" should be understood in a broad sense. For example, it may be a fixed connection, a removable connection, or an integral connection, a direct connection, an indirect connection through an intermediate medium, or a communication inside two elements. Those skilled in the art can understand the specific meaning of these terms in the present application according to the specific situation.

[0073] The term "and / or" in the present application only describes the relationship of the relevant objects, indicating that three relationships may exist. For example, A and / or B can represent three cases: A alone, the combination of A and B, and B alone. Also, the character " / " in the present application generally represents that the relevant objects before and after are in an "or" relationship.

[0074] In the examples of the present application, the same reference numerals represent the same members. For the sake of brevity, in different examples, the detailed description of the same members is omitted. It should be understood that the sizes such as the thickness, length, and width of various members in the examples of the present application shown in the drawings, and the overall thickness, length, width, etc. of the integrated device are only illustrative explanations and should not constitute any limitation to the present application.

[0075] The term "a plurality of" as used in the present application refers to two or more (including two).

[0076] The term "parallel" in this application includes not only the case of absolute parallelism but also the case of approximately parallelism which is common sense in engineering. Also, "perpendicular" includes not only the case of absolute perpendicularity but also the case of approximately perpendicularity which is common sense in engineering.

[0077] In this application, the battery cell may include, for example, a lithium-ion secondary battery cell, a lithium-ion primary battery cell, a lithium-sulfur battery cell, a sodium-lithium-ion battery cell, a sodium-ion battery cell, or a magnesium-ion battery cell, etc. The embodiments of this application are not limited thereto.

[0078] The battery referred to in the embodiments of this application refers to a single physical module including one or more battery cells to provide a higher voltage and capacity. For example, the battery referred to in this application may include a battery module or a battery pack, etc. A battery generally includes a housing for packaging one or more battery cells. The housing can avoid the influence of liquid or other foreign matters on the charging or discharging of the battery cells.

[0079] The battery cell includes an electrode assembly and an electrolyte. The electrode assembly includes a positive electrode plate, a negative electrode plate, and a separator. The battery cell operates mainly by the movement of metal ions between the positive electrode plate and the negative electrode plate. The positive electrode plate includes a positive electrode current collector and a positive electrode active material layer. The positive electrode active material layer is coated on the surface of the positive electrode current collector. The positive electrode current collector includes a positive electrode current collecting portion and a positive electrode tab. The positive electrode active material layer is coated on the positive electrode current collecting portion, and the positive electrode tab is not coated with the positive electrode active material layer. Taking a lithium-ion battery as an example, the material of the positive electrode current collector may be aluminum. The positive electrode active material layer includes a positive electrode active material, and the positive electrode active material may be lithium cobaltate, lithium iron phosphate, ternary lithium, lithium manganate, or the like. The negative electrode plate includes a negative electrode current collector and a negative electrode active material layer. The negative electrode active material layer is coated on the surface of the negative electrode current collector. The negative electrode current collector includes a negative electrode current collecting portion and a negative electrode tab. The negative electrode active material layer is coated on the negative electrode current collecting portion, and the negative electrode tab is not coated with the negative electrode active material layer. The material of the negative electrode current collector may be copper. The negative electrode active material layer includes a negative electrode active material, and the negative electrode active material may be carbon or silicon, or the like. The material of the separator may be PP (polypropylene) or PE (polyethylene), or the like.

[0080] The battery cell further includes a case for accommodating the electrode assembly and electrode terminals installed on the case. The electrode terminals are electrically connected to the electrode assembly and are used to realize the charge and discharge of the electrode assembly. In order to easily realize the assembly and ensure the overcurrent capacity of the battery cell, the battery cell generally connects the tab of the electrode assembly and the electrode terminals by a current collecting component.

[0081] To reduce resistance and improve overcurrent, the inventor generally adopts a welding method to connect the electrode terminal and the current collector component. The inventor first noticed that when welding the current collector component and the electrode terminal and then attaching the electrode terminal to the case, metal particles due to welding may adhere to the electrode terminal or the current collector component and may fall inside the case during the assembly process. Metal particles falling inside the case may break through the separator of the electrode assembly, causing a short-circuit risk.

[0082] To reduce the metal particles falling into the case, the inventor first attempts to attach the electrode terminal to the case and then weld the current collector component and the electrode terminal from the outside of the electrode terminal. In this way, the case can block the metal particles and reduce the metal particles entering the case.

[0083] However, the inventor found that when welding the electrode terminal and the current collector component from the outside of the electrode terminal during the welding process, the electrode terminal needs to melt and fall off. However, the electrode terminal generally has a relatively large thickness, the power required for welding is large, the heat generated by welding is high, and the heat generated is conducted to other components, such as the sealing component, the electrode assembly, etc., and these components are easily damaged, causing safety concerns.

[0084] In view of this, the embodiments of the present application provide a technical solution. By arranging to open a concave portion in the electrode terminal, the thickness of the portion of the electrode terminal to be welded to the current collector component is reduced, the welding difficulty is further reduced, the welding heat generation is reduced, and the safety is improved.

[0085] The technical solution described in the embodiments of the present application is applicable to batteries and power-consuming devices using the batteries.

[0086] The power consumption device may be a vehicle, a mobile phone, a portable device, a notebook computer, a steamship, an aircraft, an electric toy, or an electric tool, etc. The vehicle may be a fuel oil vehicle, a gas vehicle, or a new energy vehicle. The new energy vehicle may be a pure electric vehicle, a hybrid vehicle, or a range extender vehicle, etc. The aircraft includes airplanes, rockets, space shuttles, and spaceships, etc. The electric toy includes stationary or mobile electric toys, such as game consoles, electric vehicle toys, electric steamship toys, and electric airplane toys, etc. The electric tool includes metal cutting electric tools, grinding electric tools, assembly electric tools, and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric drivers, electric hammers, hammer drills, concrete vibrators, and electric cutters, etc. The embodiments of the present application do not particularly limit the above power consumption device.

[0087] For the convenience of description, the following embodiments will be described by taking the power consumption device as a vehicle as an example.

[0088] Figure 1 is a schematic structural diagram of a vehicle according to some embodiments of the present application. As shown in Figure 1, a battery 2 is installed inside the vehicle 1, and the battery 2 may be installed at the bottom, head, or rear of the vehicle 1. The battery 2 may be used for power supply of the vehicle 1. For example, the battery 2 may be used as the operating power supply of the vehicle 1.

[0089] The vehicle 1 may further include a controller 3 and a motor 4. The controller 3 is used to control the battery 2 to supply power to the motor 4, and is used for, for example, starting the vehicle 1, navigation, and the power consumption requirements during operation.

[0090] In some embodiments of the present application, the battery 2 can provide driving power to the vehicle 1 as the driving power source of the vehicle 1, instead of, or partly instead of, fuel oil or natural gas, in addition to being the operating power source of the vehicle 1.

[0091] Figure 2 is a schematic exploded view of a battery according to some embodiments of the present application. As shown in Figure 2, the battery 2 includes a housing 5 and a battery cell (not shown in Figure 2), and the battery cell is housed within the housing 5.

[0092] The housing 5 is used to house the battery cell, and the housing 5 may have various structures. In some embodiments, the housing 5 may include a first housing part 5a and a second housing part 5b. The first housing part 5a and the second housing part 5b overlap each other, and the first housing part 5a and the second housing part 5b together define a housing space 5c for housing the battery cell. The second housing part 5b may have a hollow structure with one end open, and the first housing part 5a may have a plate-like structure. The first housing part 5a is placed over the opening side of the second housing part 5b to form the housing 5 having the housing space 5c. Both the first housing part 5a and the second housing part 5b may have a hollow structure with one side open, and the opening side of the first housing part 5a is placed over the opening side of the second housing part 5b to form the housing 5 having the housing space 5c. Of course, the first housing part 5a and the second housing part 5b may have various shapes, such as a cylindrical body, a rectangular parallelepiped, etc.

[0093] In order to improve the sealing property after the first housing part 5a and the second housing part 5b are connected, a sealing member, such as a sealant, a sealing ring, etc., may be installed between the first housing part 5a and the second housing part 5b.

[0094] Assuming that the first housing part 5a is placed over the top of the second housing part 5b, the first housing part 5a may be referred to as an upper housing lid, and the second housing part 5b may be referred to as a lower housing.

[0095] In the battery 2, the number of battery cells may be one or plural. When there are plural battery cells, the plural battery cells may be connected in series, in parallel, or in series-parallel. Series-parallel connection means that in the plural battery cells, some are connected in series and some are connected in parallel. The plural battery cells may be directly connected in series, in parallel, or in series-parallel, and then the whole formed by the plural battery cells may be housed in the housing 5. Of course, the plural battery cells may first be connected in series, in parallel, or in series-parallel to form a battery module 6, and the plural battery modules 6 may then be connected in series, in parallel, or in series-parallel to form a whole and be housed in the housing 5.

[0096] Figure 3 is a schematic structural diagram of the battery module shown in Figure 2.

[0097] In some embodiments, as shown in Figure 3, there are plural battery cells 7, and the plural battery cells 7 are first connected in series, in parallel, or in series-parallel to form a battery module 6. The plural battery modules 6 are then connected in series, in parallel, or in series-parallel to form a whole and are housed in the housing.

[0098] The electrical connection between the plural battery cells 7 in the battery module 6 can be realized by the bus bar member 8, and the parallel connection, series connection, or series-parallel connection of the plural battery cells 7 in the battery module 6 can be realized. The number of bus bar members may be one or plural, and each bus bar member 8 is used to electrically connect at least two battery cells.

[0099] Figure 4 is a schematic exploded view of a battery cell according to some embodiments of the present application, Figure 5 is a schematic cross-sectional view of a battery cell according to some embodiments of the present application, Figure 6 is a schematic partial enlarged view of the battery cell shown in Figure 5, Figure 7 is a schematic enlarged view of the square frame B in Figure 6, and Figure 8 is a schematic enlarged view of the circular frame C in Figure 7.

[0100] As shown in FIGS. 4 to 8, the battery cell 7 of some embodiments of the present application includes an electrode assembly 10, a case 20, an electrode terminal 30, and a current collecting component 40. The electrode assembly 10 includes a first tab 11. The case 20 is used to accommodate the electrode assembly 10. The electrode terminal 30 is installed on the case 20, and the electrode terminal 30 includes a first recess 31 and a connection portion 32 located at the bottom of the first recess 31. The current collecting component 40 is connected to the first tab 11 and welded to the connection portion 32.

[0101] The electrode assembly 10 includes a first electrode plate and a second electrode plate with opposite polarities. One of the first electrode plate and the second electrode plate is a positive electrode plate, and the other is a negative electrode plate. Exemplarily, the electrode assembly 10 generates electrical energy through oxidation and reduction reactions during the occlusion / detachment of ions in the positive and negative electrode plates. Optionally, the electrode assembly 10 further includes a separator for insulating and separating the first electrode plate and the second electrode plate.

[0102] In some examples, the first electrode plate, the second electrode plate, and the separator are all in a strip structure, and the first electrode plate, the second electrode plate, and the separator are integrally wound around the central axis A to form a wound structure. The wound structure may be a cylindrical structure, a flat structure, or a structure of other shapes. In some other examples, the electrode assembly 10 may be a laminated structure formed by laminating the first electrode plate, the separator, and the second electrode plate.

[0103] The first tab 11 may be a portion of the first electrode plate where the active material layer is not coated. The first tab 11 may be a positive tab or a negative tab.

[0104] The case 20 has a hollow structure, and its interior forms a space for accommodating the electrode assembly 10. The case 20 may have various shapes and various sizes, such as a rectangular parallelepiped shape, a cylindrical shape, a hexagonal prism shape, etc. The shape of the case 20 may be determined according to the specific shape of the electrode assembly 10. For example, when the electrode assembly 10 has a cylindrical structure, a cylindrical case can be selected, and when the electrode assembly 10 has a rectangular parallelepiped structure, a rectangular parallelepiped case can be selected. Optionally, both the electrode assembly 10 and the case 20 are cylindrical.

[0105] The material of the case 20 is various, and for example, it may be copper, iron, aluminum, stainless steel, aluminum alloy, etc., and the embodiments of the present application do not particularly limit this.

[0106] The case 20 may be positively charged, negatively charged, or not charged.

[0107] The electrode terminal 30 may be used as the output electrode of the battery cell 7, and it can electrically connect the battery cell 7 to an external circuit to realize the charge and discharge of the battery cell 7. Optionally, the electrode terminal 30 is connected to a bus bar member and is used to realize the electrical connection between the battery cells 7.

[0108] The electrode terminal 30 may be installed on the case 20 in an insulating manner or may be electrically connected to the case 20. The embodiments of the present application do not limit this, and it is only necessary to avoid the conduction between the positive electrode plate and the negative electrode plate.

[0109] The first recess 31 may be recessed along the direction from the side away from the electrode assembly 10 of the electrode terminal 30 towards the electrode assembly 10, or may be recessed along the direction from the side of the electrode terminal 30 towards the electrode assembly 10 away from the electrode assembly 10.

[0110] The connection portion 32 is a portion corresponding to the bottom surface of the first recess 31 of the electrode terminal 30.

[0111] The current collector component 40 electrically connects the first tab 11 to the electrode terminal 30. The embodiments of the present application do not limit the connection method between the first tab 11 and the current collector component 40. For example, the current collector component 40 may be connected to the first tab 11 by means such as welding, abutting, or adhesion.

[0112] The current collector component 40 and the connection part 32 are connected by welding. Exemplarily, the current collector component 40 and the connection part 32 are connected by laser welding.

[0113] In the embodiments of the present application, by opening the first recess 31 in the electrode terminal 30 to reduce the thickness of the connection part 32, the welding power required for the connection part 32 to be welded to the current collector component 40 is reduced, heat generation is reduced, the risk of other components being burned out is reduced, and safety is improved.

[0114] In some embodiments, the electrode assembly 10 includes a main body part 12, a first tab 11, and a second tab 13, and the first tab 11 and the second tab 13 protrude from the main body part 12. The first tab 11 is a portion of the first electrode plate where the active material layer is not coated, and the second tab 13 is a portion of the second electrode plate where the active material layer is not coated.

[0115] The first tab 11 and the second tab 13 may extend from the same side of the main body part 12, or may extend from opposite sides respectively. Exemplarily, the first tab 11 is located at the end facing the electrode terminal 30 of the electrode assembly 10, and the second tab 13 is located at the end away from the electrode terminal 30 of the electrode assembly 10.

[0116] In some embodiments, the first tab 11 is wound around the central axis A of the electrode assembly 10 in multiple turns. In other words, the first tab 11 includes multiple wound tab layers. After the winding is completed, the first tab 11 is substantially cylindrical, and there is a gap between two adjacent wound tab layers. The embodiments of the present application can process the first tab 11 to reduce the gap between the tab layers and facilitate the connection between the first tab 11 and the current collecting component 40. For example, in the embodiments of the present application, the first tab 11 can be subjected to a kneading and flattening process such that the end region away from the main body portion 12 of the first tab 11 is constricted and converged. Through the kneading and flattening process, a dense end face is formed at one end of the first tab 11 away from the main body portion 12, the gap between the tab layers is reduced, and the connection between the first tab 11 and the current collecting component 40 is facilitated. Alternatively, in the embodiments of the present application, a conductive material can be filled between two adjacent wound tab layers to reduce the gap between the tab layers.

[0117] In some embodiments, the second tab 13 is wound around the central axis A of the electrode assembly 10 in multiple turns. The second tab 13 includes multiple wound tab layers. Exemplarily, the second tab 13 is also subjected to a kneading and flattening process to reduce the gap between the tab layers of the second tab 13.

[0118] The central axis A of the electrode assembly 10 is a virtual straight line. The first electrode plate, the second electrode plate, and the separator may be wound with reference to the central axis A.

[0119] In some embodiments, the case 20 includes a cylindrical body 21 and a lid body 22 connected to the cylindrical body 21. The cylindrical body 21 is installed to surround the outer periphery of the electrode assembly 10. An electrode lead-out hole 221 is provided in the lid body 22, and the electrode terminal 30 is attached to the electrode lead-out hole 221.

[0120] The lid body 22 and the cylindrical body 21 may be integrally formed, that is, the case 20 is a component formed integrally. Of course, the lid body 22 and the cylindrical body 21 are two separate components and may be connected by means such as welding, caulking, or adhesion.

[0121] The electrode lead-out hole 221 penetrates through the lid body 22 so as to facilitate the extraction of electrical energy in the electrode assembly 10 to the outside of the case 20.

[0122] The central axis A is an imaginary straight line passing through the electrode lead-out hole 221. The central axis A of the electrode assembly 10 and the axis of the electrode lead-out hole 221 may or may not coincide.

[0123] The electrode terminal 30 is fitted into the electrode lead-out hole 221 and used to cover the electrode lead-out hole 221. The electrode terminal 30 may or may not enter the electrode lead-out hole 221. The electrode terminal 30 is fixed to the lid body 22. The electrode terminal 30 may be fixed entirely outside the lid body 22, or may enter the inside of the case 20 through the electrode lead-out hole 221.

[0124] In some embodiments, the lid body 22 and the cylindrical body 21 are integrally formed. In this way, the connection process between the lid body 22 and the cylindrical body 21 can be omitted.

[0125] When the lid body 22 and the cylindrical body 21 are electrically connected to the positive electrode or the negative electrode of the electrode assembly 10, since the connection portion between the lid body 22 and the cylindrical body 21 is an integral structure, the resistance of the connection portion between the lid body 22 and the cylindrical body 21 is relatively small, thereby enhancing the overcurrent capacity. The lid body 22 may be used to connect to external components (for example, bus bar members). When the battery cell is subjected to an external impact, the external component may pull the lid body 22, and a force may act on the connection portion between the lid body 22 and the cylindrical body 21. The above technical solution improves the strength of the connection portion between the lid body 22 and the cylindrical body 21 by integrally installing the lid body 22 and the cylindrical body 21, and reduces the risk of the connection between the lid body 22 and the cylindrical body 21 failing.

[0126] In some embodiments, the case 20 may be formed by an extrusion process.

[0127] In some embodiments, at the end away from the electrode terminal 30 of the case 20, there is an opening 211, and the battery cell 7 further includes a cover plate 50 for sealing the opening 211.

[0128] Specifically, at the end away from the lid 22 of the cylindrical body 21, there is an opening, and the cover plate 50 is placed over the opening of the cylindrical body 21 to seal the opening of the cylindrical body 21. The cover plate 50 may have various structures. For example, the cover plate 50 has a plate-like structure.

[0129] In some embodiments, the cover plate 50 may be a circular cover plate, a rectangular cover plate, a square cover plate, a hexagonal cover plate, or a cover plate of other shapes.

[0130] In some embodiments, the cover plate 50 is welded to the cylindrical body 21.

[0131] In some embodiments, the lid 22 is circular, the electrode assembly 10 is cylindrical, and the central axis A coincides with the axis of the electrode lead-out hole 221. This embodiment does not require the central axis A to completely coincide with the axis of the electrode lead-out hole 221, and there may be a tolerance allowed in the process between the two.

[0132] In this embodiment, the electrode lead-out hole 221 is provided substantially in the middle of the lid 22, and accordingly, the electrode terminal 30 is also attached to the middle of the lid 22. When assembling a plurality of battery cells 7 into a group, the requirement for the positioning accuracy of the electrode terminal 30 can be reduced, and the assembly process can be simplified.

[0133] Exemplarily, the axis of the electrode lead-out hole 221 coincides with the axis of the lid 22, and the lid 22 is an annular structure installed around the axis of the electrode lead-out hole 221.

[0134] Exemplarily, the axis of the electrode terminal 30 coincides with the axis of the electrode lead-out hole 221.

[0135] In some other embodiments, the lid 22 may be rectangular, and the electrode assembly 10 may be flat. The electrode lead hole 221 may be installed near the end along the longitudinal direction of the lid 22 itself.

[0136] In some embodiments, the electrode assembly 10 further includes a second tab 13 that is opposite in polarity to the first tab 11, and the second tab 13 is installed around the central axis A of the electrode assembly 10. The first tab 11 is provided at the end facing the electrode terminal 30 of the electrode assembly 10, the second tab 13 is provided at the end away from the electrode terminal 30 of the electrode assembly 10, and the second tab 13 is electrically connected to the case 20.

[0137] The case 20 itself serves as one output electrode of the battery cell 7, thereby saving one conventional electrode terminal and simplifying the structure of the battery cell 7. When assembling a plurality of battery cells 7 in a group, the case 20 may be electrically connected to the bus bar member. In this way, not only can the overcurrent area be increased, but also the structural design of the bus bar member can be made more flexible.

[0138] In some embodiments, the second tab 13 is a negative tab, and the base material of the case 20 is steel. The case 20 is electrically connected to the negative tab, that is, the case 20 is in a low potential state. The steel case 20 is not easily corroded by the electrolyte in the low potential state.

[0139] In some embodiments, the cylindrical body 21 is used to connect the second tab 13 and the lid 22 so that the second tab 13 is electrically connected to the lid 22.

[0140] The cylindrical body 21 may be directly electrically connected to the second tab 13, or may be electrically connected to the second tab 13 by other components. For example, the second tab 13 is electrically connected to the cylindrical body 21 by the cover plate 50.

[0141] The cover body 22 and the electrode terminal 30 have different polarities. At this time, one of the cover body 22 and the electrode terminal 30 may be used as the positive output electrode of the battery cell 7, and the other may be used as the negative output electrode of the battery cell 7. In this embodiment, the positive output electrode and the negative output electrode are installed on the same side of the battery cell 7, and thus the connection process between the plurality of battery cells 7 can be simplified.

[0142] The electrode lead-out hole 221 of the embodiment of the present application is formed after the stretching and forming of the case 20.

[0143] The inventor once tried to fold the open end of the cylindrical body inward by roll pressing the open end of the cylindrical body to form a burring structure, and the burring structure presses the cover plate to realize the fixation of the cover plate. The inventor attached the electrode terminal to the cover plate, and used the burring structure and the electrode terminal as the two output electrodes of the battery cell. However, the larger the size of the burring structure, the higher the risk of curling and wrinkling after its forming. When curling and wrinkling occur in the burring structure, unevenness will occur on the surface of the burring structure. When the burring structure is welded to an external bus bar member, there will be a problem of welding defects. Therefore, the size of the burring structure is relatively limited, which causes the overcurrent capacity of the battery cell to be insufficient.

[0144] This embodiment utilizes the process of opening holes to form the electrode lead-out hole 221 for attaching the electrode terminal 30 to the cover body 22, and installs the positive output electrode and the negative output electrode at the end of the battery cell 7 away from the opening of the cylindrical body 21. The cover body 22 is formed during the forming process of the case 20, and the flatness can be ensured even after the electrode lead-out hole 221 is opened, and the connection strength between the cover body 22 and the bus bar member is ensured. At the same time, since the flatness of the cover body 22 is not restricted by its own size, the cover body 22 can improve the overcurrent capacity of the battery cell 7 by having a relatively large size.

[0145] In some embodiments, the current collector component 40 is welded to the connection portion 32 to form a first weld portion W1. In the thickness direction X of the connection portion 32, the first weld portion W1 extends from the side of the connection portion 32 away from the current collector component 40 to at least the inside of the current collector component 40.

[0146] During welding, a part of the connection portion 32 and a part of the current collector component 40 are melted to form a molten pool, and the first weld portion W1 is formed after the molten pool solidifies. Exemplarily, after the electrode assembly 10 and the current collector component 40 are installed in the case 20 and the current collector component 40 is pressed against the connection portion 32, an external welding device can weld the connection portion 32 and the current collector component 40 from the side of the connection portion 32 away from the current collector component 40 to form the first weld portion W1. The first weld portion W1 is exposed on the surface of the connection portion 32 away from the current collector component 40.

[0147] The embodiments of the present application do not particularly limit the shape, position, depth, and number of the first weld portion W1. For example, the shape of the first weld portion W1 may be linear, C-shaped, annular, spiral, V-shaped, or other shapes. The first weld portion W1 may be one or a plurality.

[0148] The first weld portion W1 can penetrate the current collector component 40. For example, the first weld portion W1 penetrates through the current collector component 40 and the connection portion 32, and the first weld portion W1 is exposed on the surface of the current collector component 40 away from the connection portion 32. Of course, the first weld portion W1 does not have to penetrate the current collector component 40, that is, the first weld portion W1 is not exposed on the surface of the current collector component 40 away from the connection portion 32.

[0149] The first weld portion W1 extends from the connection portion 32 to the inside of the current collector component 40, connects the current collector component 40 and the connection portion 32, reduces the contact resistance between the current collector component 40 and the electrode terminal 30, and improves the overcurrent capacity.

[0150] In some embodiments, in the thickness direction X of the connection portion 32, the first weld portion W1 does not protrude beyond the surface of the current collector component 40 away from the connection portion 32.

[0151] The surface that is separated from the connection part 32 between the first welding part W1 and the current collecting component 40 is at a predetermined distance to avoid the melting of the current collecting component 40, reduce the risk of generating metal particles on the surface separated from the connection part 32 of the current collecting component 40, and improve safety.

[0152] In some embodiments, the case 20 includes a cylindrical body 21 and a lid body 22 connected to the cylindrical body 21. The cylindrical body 21 is installed to surround the outer periphery of the electrode assembly 10. The lid body 22 is provided with an electrode lead-out hole 221, and the electrode terminal 30 is attached to the electrode lead-out hole 221. Both the first welding part W1 and the lid body 22 are annular. The outer diameter of the lid body 22 is D0, and the inner diameter of the first welding part W1 is D1. D1 and D0 satisfy 0.1 ≦ D1 / D0 ≦ 0.6.

[0153] The first welding part W1 may have a sealed structure or an unsealed structure. In other words, the first welding part W1 may be a semi-annular ring or the entire annular ring.

[0154] D0 has a positive correlation with the diameter of the electrode assembly 10. The larger D0 is, the higher the capacity of the electrode assembly 10 is, and the higher the requirements for the battery cell 7 for the overcurrent area of the first welding part W1 are. The smaller D1 is, the smaller the perimeter of the first welding part W1 is, and the smaller the overcurrent area of the first welding part W1 is. If D1 / D0 is too small, since D0 is large and D1 is small, the overcurrent area of the first welding part W1 is insufficient, the heat generation of the first welding part W1 during charge and discharge is relatively large, and it is difficult to meet the requirements of the battery cell 7 for the overcurrent capacity and temperature rise during rapid charging. As a result of intensive research and a large number of experiments by the inventor, it has been found that when D1 / D0 ≧ 0.1, the requirements of the battery cell 7 for the overcurrent capacity and temperature rise can be met.

[0155] The larger D1 is, the larger the size of the electrode lead-out hole 221 is, and the smaller the area of the lid body 22 is. Similarly, the smaller D0 is, the smaller the area of the lid body 22 is. If D1 / D0 is too large, since D0 is small and D1 is large, when the battery cell 7 is vibrating, the lid body 22 is likely to be deformed, causing safety concerns. The lid body 22 can be connected to the bus bar member as one output pole of the battery cell 7. If D1 / D0 is too large, the connection area between the lid body 22 and the bus bar member is small, the overcurrent area between the lid body 22 and the bus bar member is insufficient, the heat generation at the connection location between the lid body 22 and the bus bar member is high, and it is difficult to meet the requirements of the battery cell 7 for overcurrent capacity and temperature rise during rapid charging. As a result of intensive research and a large number of experiments by the inventor, it has been found that when D1 / D0≤0.6, the requirements of the battery cell 7 for overcurrent capacity and temperature rise can be met, and the safety of the battery cell 7 can be improved.

[0156] D1 / D0 may be 0.1, 0.2, 0.3, 0.4, 0.5 or 0.6.

[0157] In some embodiments, as a result of intensive research and a large number of experiments by the inventor, it has been found that when 0.2≤D1 / D0≤0.4, the requirements of the battery cell 7 for overcurrent capacity and temperature rise can be better met, and the safety of the battery cell 7 can be improved.

[0158] In some embodiments, D1 is 5 mm to 14 mm.

[0159] If D1 is too small, the overcurrent area of the first welding part W1 is insufficient, the heat generation of the first welding part W1 during charge and discharge is relatively large, and it is difficult to meet the requirements of the battery cell 7 for overcurrent capacity and temperature rise during rapid charging. If D1 is too large, the overcurrent area between the lid body 22 and the bus bar member is insufficient, resulting in high heat generation at the connection location between the lid body 22 and the bus bar member. As a result of intensive research and a large number of experiments by the inventor, it has been found that by limiting D1 to 5 mm to 14 mm, the requirements of the battery cell 7 for overcurrent capacity and temperature rise can be met.

[0160] Optionally, D1 is 5 mm, 7 mm, 9 mm, 10 mm, 12 mm or 14 mm.

[0161] In some embodiments, in the thickness direction X of the connection part 32, the size of the first welding part W1 is h, and the thickness of the region for welding to the current collecting component 40 of the connection part 32 is d0. d0 and h satisfy 1 < h / d0 ≤ 1.5.

[0162] The first welding part W1 is annular, and due to process errors, different regions of the first welding part W1 may have different penetrations in the thickness direction X. h may be the size along the thickness direction X of the region where the penetration of the first welding part W1 is the smallest.

[0163] In some examples, the connection part 32 has a flat plate structure with a uniform thickness, and any part of the connection part 32 may be used for welding to the current collecting component 40, and d0 is the thickness of the connection part 32. In some other examples, the connection part 32 has a non-uniform thickness structure, and the region where the thickness of the connection part 32 is relatively small may be the region for welding to the current collecting component 40 of the connection part 32. In this way, the power required for welding can be reduced and heat generation can be reduced. For example, the connection part 32 can reduce the local thickness by opening a concave groove, and the region corresponding to the concave groove of the connection part 32 may be the region for welding to the current collecting component 40 of the connection part 32.

[0164] When h / d0 ≤ 1, the penetration of the first welding part W1 is relatively small. When the entire first welding part W1 is formed on the connection part 32, it causes dummy welding, and the first welding part W1 is difficult to effectively connect the current collecting component 40 and the connection part 32. When d0 is constant, the larger h is, the greater the power required for welding, and the higher the heat generation during the welding process. If h is too large, the high temperature caused by welding is likely to damage the members around the electrode terminal 30, causing safety concerns.

[0165] As a result of intensive research and a large number of experiments, the inventors have found that when 1 < h / d0 ≤ 1.5, on the premise that the connection between the current collector component 40 and the connection part 32 is ensured, the heat generation during welding can be reduced and the welding difficulty can be decreased.

[0166] Optionally, h / d0 is 1.05, 1.1, 1.2, 1.3, 1.4 or 1.5.

[0167] In some embodiments, the thickness of the region for welding to the connection part 32 of the current collector component 40 is d1, and d0 and d1 satisfy 0.5 ≤ d1 / d0 ≤ 1.2.

[0168] The region for welding to the connection part 32 of the current collector component 40 is the region that abuts against the connection part 32 of the current collector component 40.

[0169] When d0 is constant, the smaller d1 is, the easier the current collector component 40 is to melt and fall off during the welding process, and the easier the high-temperature particles due to welding are to fall into the battery cell 7. The larger d1 is, the larger the space and weight occupied by the current collector component 40 are, and the lower the energy density of the battery cell 7 is.

[0170] As a result of intensive research and a large number of experiments, the inventors have found that when 0.5 ≤ d1 / d0 ≤ 1.2, the risk of the current collector component 40 melting and falling off can be reduced, and the loss of the energy density of the battery cell 7 can be decreased.

[0171] Optionally, d1 / d0 is 0.5, 0.7, 0.9, 1.0 or 1.2.

[0172] In some embodiments, d0 is 0.4 mm to 1.2 mm.

[0173] The smaller d0 is, the lower the overcurrent capacity of the connection part 32. If d0 is too small, the connection part 32 may not easily meet the requirements of the battery cell 7 for overcurrent capacity and temperature rise during rapid charging. The larger d0 is, the greater the power required for welding, and the higher the heat generation during the welding process. If d0 is too large, the high temperature due to welding is likely to damage the members around the electrode terminal 30, causing safety concerns.

[0174] As a result of intensive research and a large number of experiments, the inventor has found that by limiting d0 to 0.4 mm to 1.2 mm, the requirements of the battery cell 7 for overcurrent capacity and temperature rise can be met, welding heat generation can be reduced, and safety can be improved.

[0175] Optionally, d0 is 0.4 mm, 0.5 mm, 0.6 mm, 0.8 mm, 1.0 mm or 1.2 mm.

[0176] Optionally, as a result of intensive research and a large number of experiments, the inventor has found that by limiting d0 to 0.6 mm to 1.0 mm, the requirements of the battery cell 7 for overcurrent capacity and temperature rise can be better met, welding heat generation can be reduced, and safety can be improved.

[0177] In some embodiments, d1 is 0.2 mm to 0.6 mm. Optionally, d1 is 0.3 mm to 0.5 mm.

[0178] In some embodiments, at least a part of the first tab 11 is located on the side away from the electrode terminal 30 of the current collecting component 40 and is supported by the current collecting component 40.

[0179] The first tab 11 can support the current collecting component 40 such that the current collecting component 40 is bonded to the connection part 32. When the battery cell 7 is vibrating, the first tab 11 can reduce the force applied to the first weld W1 by restricting the movement of the current collecting component 40 with respect to the connection part 32, and reduce the risk of the first weld W1 being torn.

[0180] In the assembly process of the battery cell 7, by the first tab 11 supporting the current collector component 40, the current collector component 40 is brought into close contact with the connection part 32, the relative displacement generated in the welding process between the current collector component 40 and the connection part 32 can be reduced, and the risk of dummy welding can be reduced.

[0181] In some embodiments, the first portion 111 of the first tab 11 is located on the side away from the first recess 31 of the connection part 32 and is used to support the portion of the current collector component 40 facing the connection part 32.

[0182] In the thickness direction X of the connection part 32, the first portion 111 and the connection part 32 are arranged opposite to each other. In other words, the first portion 111 is the portion of the first tab 11 that overlaps the connection part 32 in the thickness direction X.

[0183] The first portion 111 can support the portion of the current collector component 40 facing the connection part 32 so as to bring the current collector component 40 into close contact with the connection part 32 and reduce the risk of dummy welding. In the welding process, the first portion 111 can also limit the deformation of the current collector component 40 and improve the form of the current collector component 40.

[0184] In some embodiments, the second portion 112 of the first tab 11 surrounds the outer periphery of the first portion 111 and is used to support the region that does not face the connection part 32 of the current collector component 40.

[0185] The second portion 112 is the portion that does not overlap the connection part 32 of the first tab 11 in the thickness direction X. Exemplarily, the second portion 112 is an annular structure.

[0186] By installing the second part 112, the area of the region supporting the current collecting component 40 of the first tab 11 can be increased, the supporting effect of the first tab 11 can be improved, the pressure between the first tab 11 and the current collecting component 40 can be reduced, and the risk of the first tab 11 being crushed can be reduced. When welding the connection part 32 and the current collecting component 40, the second part 112 can reduce the relative displacement generated between the current collecting component 40 and the connection part 32 during the welding process by supporting the current collecting component 40, and the risk of dummy welding can be reduced.

[0187] In some embodiments, in the thickness direction X of the connection part 32, the first tab 11 does not have to entirely face the connection part 32. In other words, the first tab 11 may only include the second part 112.

[0188] In some embodiments, the second part 112 is welded to the current collecting component 40 to form a third welding part W3.

[0189] When assembling the battery cell 7, first, the second part 112 of the first tab 11 of the electrode assembly 10 can be welded to the current collecting component 40, and then the electrode assembly 10 and the current collecting component 40 can be arranged in the case 20. Specifically, when welding the second part 112 and the current collecting component 40, first, the current collecting component 40 is pressed against the end face of the first tab 11 after being kneaded and flattened, and then the external welding device emits a laser to the surface of the current collecting component 40 that is separated from the first tab 11, and the current collecting component 40 and the second part 112 of the first tab 11 can be welded by the laser.

[0190] The shape of the third welding part W3 may be linear, C-shaped, annular, spiral, V-shaped, or other shapes, and this embodiment does not limit this. The third welding part W3 may be one or a plurality.

[0191] The third welding part W3 can reduce the contact resistance between the current collecting component 40 and the second part 112 and improve the overcurrent capacity.

[0192] In some embodiments, a convex portion 41 is provided on the side facing the first tab 11 of the current collecting component 40, and the convex portion 41 is welded to the second portion 112 to form a third welding portion W3.

[0193] When assembling the current collecting component 40 and the electrode assembly 10, first, the convex portion 41 of the current collecting component 40 is pressed against the second portion 112, and the convex portion 41 and the second portion 112 are welded. The convex portion 41 can be better adhered to the second portion 112, and the risk of welding defects can be reduced.

[0194] In some embodiments, the convex portion 41 can extrude and incorporate the second portion 112.

[0195] In some embodiments, other than the convex portion 41, other parts of the current collecting component 40 have a substantially flat plate structure.

[0196] In some embodiments, a second concave portion 42 is formed at a position corresponding to the convex portion 41 of the current collecting component 40. The second concave portion 42 is recessed along the direction toward the first tab 11 with respect to the surface facing away from the first tab 11 of the current collecting component 40. An adapter portion is formed between the bottom surface of the second concave portion 42 and the top surface of the convex portion 41, and the adapter portion is welded to the second portion 112 to form a third welding portion W3. By providing the second concave portion 42, the thickness of the adapter portion can be reduced, the welding power required for welding the adapter portion and the second portion 112 can be reduced, heat generation can be reduced, and the risk of the electrode assembly 10 being burned out can be reduced.

[0197] The third welding portion W3 is formed by welding, and its surface has irregularities. In this embodiment, by providing the second concave portion 42, the surface of the third welding portion W3 is recessed with respect to the surface facing away from the first tab 11 of the current collecting component 40, and the third welding portion W3 can avoid other components (such as the electrode terminal 30).

[0198] In some embodiments, a fixing sheet (not shown) may be provided in the second recess 42. The fixing sheet is used to cover the third welding portion W3 to fix the metal particles remaining on the third welding portion W3, reduce the risk of the metal particles falling onto the electrode assembly 10 and causing a short circuit. The fixing sheet may be an insulating sheet, an insulating rubber layer or other structures.

[0199] FIG. 9 is a schematic diagram of a terminal body of an electrode terminal of a battery cell according to some embodiments of the present application.

[0200] As shown in FIG. 9, in some embodiments, the first welding portion W1 has a non-closed structure, and the central angle α of the first welding portion W1 is 180° to 330°.

[0201] α has a positive correlation with the overcurrent area of the first welding portion W1. The smaller α is, the smaller the overcurrent area of the first welding portion W1 is, and the higher the heat generation is when the current flows through the first welding portion W1. In the embodiments of the present application, by limiting α to 180° to 330°, the first welding portion can meet the requirements of the battery cell for overcurrent capacity and temperature rise.

[0202] The first welding portion W1 has a non-closed structure, and the unwelded region between both ends along the circumferential direction of the first welding portion W1 can release the welding stress and reduce the stress concentration.

[0203] FIG. 10 is a schematic diagram of a terminal body of an electrode terminal of a battery cell according to some embodiments of the present application.

[0204] As shown in FIG. 10, in some embodiments, the first welding portion W1 has a closed structure. In other words, the central angle of the first welding portion W1 is 360°. The embodiments of the present application can increase the welding area and improve the welding strength and overcurrent capacity of the first welding portion.

[0205] FIG. 11 is a schematic structural diagram of an electrode assembly and a current collecting component of a battery cell according to some embodiments of the present application.

[0206] Referring to FIGS. 6 to 11 together, in some embodiments, the first tab 11 is installed around the central axis A of the electrode assembly 10, and the cross-section perpendicular to the central axis A of the first tab 11 is annular. The outer radius of the first tab 11 is R, and the minimum pitch between the third welding part W3 in the radial direction of the first tab 11 and the central axis A is D2, and both satisfy 0.2 ≦ D2 / R ≦ 0.8.

[0207] The cross-section perpendicular to the central axis A of the first tab 11 is not required to be an absolute annular shape, and a certain variation is allowed.

[0208] R has a positive correlation with the diameter of the electrode assembly 10. The larger R is, the larger the current by the electrode assembly 10 is, and the higher the requirement for the battery cell 7 for the overcurrent area is. The portion close to the central axis A of the current collector component 40 may be used for welding to the connection part 32. The smaller D2 is, the smaller the area where the connection part 32 of the current collector component 40 can be welded is, and the smaller the overcurrent area between the current collector component 40 and the connection part 32 is. If D2 / R is too small, since D2 is small and R is large, the overcurrent area between the current collector component 40 and the connection part 32 is insufficient, and the heat generation at the welding location of the current collector component 40 and the connection part 32 during charge and discharge is relatively large, making it difficult to meet the requirements of the battery cell 7 for the overcurrent capacity and temperature rise during rapid charging.

[0209] The first tab 11 includes a plurality of tab layers, and each tab layer goes around the central axis A. In the radial direction of the first tab 11, the plurality of tab layers are laminated along the radial direction of the first tab 11. The current on the tab layer directly connected to the third welding part W3 can be directly conducted to the current collector component 40 by the third welding part W3. The current on the tab layer not connected to the third welding part W3 first needs to be conducted to the tab layer directly connected to the third welding part W3 and then can be conducted to the current collector component 40 by the third welding part W3. As a result, there are differences in the conduction paths between the plurality of tab layers and the first wall. If the difference is too large, it is easy to cause polarization problems.

[0210] If D2 / R is too small, the pitch between the third welding part W3 and the outermost tab layer is too large, and the difference between the current path between the outermost tab layer and the electrode terminal 30 and the current path between the innermost tab layer and the electrode terminal 30 is large, resulting in non-uniform current density in the first electrode plate of the electrode assembly 10 and an increase in internal resistance.

[0211] As a result of intensive research and a large number of experiments, the inventor has found that when D2 / R ≥ 0.2, the requirements for the overcurrent capacity and temperature rise of the battery cell 7 can be met.

[0212] The larger D2 is, the more outward the tab layer directly connected to the third welding part W3 is. If D2 is too large, the number of tab layers connected to the third welding part W3 is small, resulting in too large a pitch between the third welding part W3 and the innermost tab layer, and the difference between the current path between the outermost tab layer and the electrode terminal 30 and the current path between the innermost tab layer and the electrode terminal 30 is large, resulting in non-uniform current density in the first electrode plate and an increase in internal resistance.

[0213] As a result of intensive research and a large number of experiments, the inventor has found that when D2 / R ≤ 0.8, the difference in the current path between different positions of the first tab 11 and the electrode terminal 30 can be reduced, the uniformity of the current density in the first electrode plate of the electrode assembly 10 can be improved, the internal resistance can be reduced, and the overcurrent capacity can be improved.

[0214] Optionally, D2 / R is 0.2, 0.3, 0.5, 0.7 or 0.8.

[0215] In some embodiments, as a result of intensive research and a large number of experiments, the inventor has found that when D2 and R satisfy 0.2 ≤ D2 / R ≤ 0.5, the overcurrent capacity of the battery cell 7 can be better improved and the temperature rise of the battery cell can be reduced.

[0216] In some embodiments, D2 is 3.5 mm to 10 mm.

[0217] If D2 is too small, the overcurrent area between the current collecting component 40 and the connection part 32 is insufficient, and the heat generation at the welding location between the current collecting component 40 and the connection part 32 during charge and discharge is relatively large, making it difficult to meet the requirements of the battery cell 7 for overcurrent capacity and temperature rise during rapid charging. As a result of intensive research and a large number of experiments, the inventor has found that when D2≥3.5 mm, the requirements of the battery cell 7 for overcurrent capacity and temperature rise can be met.

[0218] If D2 is too large, the number of tab layers connected to the third welding part W3 is small, the distance between the tab layer close to the central axis A and the third welding part W3 is too large, the internal resistance of the electrode assembly 10 is large, which will affect the performance of the battery cell 7. As a result of intensive research and a large number of experiments, the inventor has found that when D2≤10 mm, the internal resistance of the electrode assembly 10 can be reduced and the charge and discharge performance of the battery cell 7 can be improved.

[0219] Optionally, D2 is 3.5 mm, 4 mm, 5 mm, 7 mm, 8.5 mm or 10 mm.

[0220] In some embodiments, R is 20 mm to 22.8 mm.

[0221] In some embodiments, the third welding part W3 is annular. The annular third welding part W3 has a relatively large overcurrent area, can improve the uniformity of the current density of the first electrode plate, reduce the internal resistance, and improve the overcurrent capacity.

[0222] In some embodiments, the diameter of the current collecting component 40 is D3, the diameter of the first tab 11 is D4, and D3 is smaller than D4.

[0223] D3 is the diameter of the outer edge of the current collecting component 40, that is, the outer diameter of the current collecting component 40. D4 is the diameter of the outer edge of the first tab 11, that is, the outer diameter of the first tab 11. Exemplarily, D4 = 2*R.

[0224] The current collecting component 40 has a relatively small diameter, which can save the space and weight occupied by the current collecting component 40 and increase the energy density of the battery cell 7.

[0225] In some embodiments, D3 and D4 satisfy 0.75 ≦ D3 / D4 ≦ 0.97.

[0226] When D4 is constant, if D3 is too small, the distance between the outer part of the first tab 11 and the current collecting component 40 is too large, the conductive path between the outer part of the first tab 11 and the current collecting component 40 is too long, the internal resistance of the electrode assembly 10 is large, which will affect the performance of the battery cell 7. As a result of intensive research and a large number of experiments, the inventor has found that when D3 / D4 ≧ 0.75, the internal resistance of the electrode assembly 10 can be reduced and the charge and discharge performance of the battery cell 7 can be improved.

[0227] When D4 is constant, if D3 is too large, due to assembly errors, the coaxiality between the current collecting component 40 and the electrode assembly 10 will vary, causing the current collecting component 40 to protrude from the outer peripheral surface of the electrode assembly 10. The incorporation of the current collecting component 40 and the electrode assembly 10 into the case will become difficult, affecting the assembly efficiency and the superiority of the product. As a result of intensive research and a large number of experiments, the inventor has found that when D3 / D4 ≦ 0.97, the risk that the current collecting component 40 protrudes from the outer peripheral surface of the electrode assembly 10 due to errors can be reduced, and the assembly efficiency and the superiority of the product can be improved.

[0228] Optionally, D3 / D4 may be 0.75, 0.8, 0.85, 0.9, 0.95 or 0.97.

[0229] In some embodiments, D3 is 35 mm to 44 mm. As a result of intensive research and a large number of experiments, the inventor has found that by limiting D3 to 35 mm to 44 mm, the internal resistance of the electrode assembly 10 can be reduced, the charge and discharge performance of the battery cell 7 can be improved, and the risk that the current collecting component 40 protrudes from the outer peripheral surface of the electrode assembly 10 due to errors can be reduced.

[0230] Optionally, D3 may be 35 mm, 38 mm, 40 mm, 41 mm, 43 mm or 44 mm.

[0231] In some embodiments, as a result of intensive research and a large number of experiments by the inventors, it has been found that by limiting D3 to 38 mm to 41 mm, the internal resistance of the electrode assembly 10 can be better reduced and the charge and discharge performance of the battery cell 7 can be improved.

[0232] In some embodiments, the connection part 32 is provided with a concave groove 324 that recesses along the direction from the first outer surface 322 of the connection part 32 towards the electrode assembly 10, and the first welding part W1 extends from the bottom wall of the concave groove 324 to at least the inside of the current collecting component 40.

[0233] The connection part 32 has a first outer surface 322 and a first inner surface 321 that are oppositely arranged along the thickness direction X of itself. The first inner surface 321 faces towards the current collecting component 40, and the first outer surface 322 faces away from the current collecting component 40. Optionally, both the first outer surface 322 and the first inner surface 321 are flat surfaces.

[0234] The concave groove 324 recesses along the direction towards the current collecting component 40 with respect to the first outer surface 322. In this embodiment, by opening the concave groove 324 in the connection part 32, a stepped structure is formed in the connection part 32. A gap is formed between the first outer surface 322 and the bottom wall of the concave groove 324.

[0235] The portion between the bottom wall of the concave groove 324 and the first inner surface 321 may be a region for welding to the current collecting component 40 of the connection part 32. In other words, the portion between the bottom wall of the concave groove 324 and the first inner surface 321 is used to be welded to the current collecting component 40 to form the first welding part W1.

[0236] In the production process of the battery cell 7, it is necessary to fit an external device to the connection part 32. There are irregularities on the surface of the first welding part W1. When the external device is pressed against the first welding part W1, the external device is likely to be damaged by the first welding part W1. In this embodiment, by providing the concave groove 324, a gap is formed between the first outer surface 322 and the bottom wall of the concave groove 324. In this way, the first outer surface 322 can be used to support the external device so as to separate the external device from the first welding part W1 and reduce the risk of the external device being damaged.

[0237] Exemplarily, the external device may be a liquid injection device, a gas extraction device, a welding device, or other devices used for the battery cell 7.

[0238] In some embodiments, the connection part 32 is provided with a first through hole 323, and the first through hole 323 is used to communicate the space located on the side away from the electrode assembly 10 of the connection part 32 with the internal space of the case 20.

[0239] The first through hole 323 penetrates the connection part 32 along the thickness direction X of the connection part 32. The first through hole 323 may be one or a plurality.

[0240] When welding the connection part 32 and the current collecting component 40, the first through hole 323 plays a role in releasing welding stress and can reduce the risk of the connection part 32 bursting.

[0241] In the forming process of the battery cell 7, the first through hole 323 may be used in a plurality of forming processes. For example, the first through hole 323 may be applied to a liquid injection process, a formation process, or other processes.

[0242] Specifically, the first through hole 323 is used to inject electrolyte into the internal space of the case 20. When liquid injection is required, the liquid injection head of the liquid injection device is pressed against the connection part 32, and the liquid injection head injects electrolyte into the case 20 through the first through hole 323.

[0243] During the formation process of the battery cell 7, gas is generated inside the case 20, and the first through hole 323 may be used to communicate with an external negative pressure device to discharge the gas inside the case 20.

[0244] In some embodiments, the axis of the first through hole 323 coincides with the axis of the electrode lead-out hole 221.

[0245] In some embodiments, the current collector component 40 is provided with a second through hole 45, and the second through hole 45 is configured to be installed opposite to the first through hole 323, so that the electrolyte can flow into the internal space of the case 20 through the second through hole 45.

[0246] The axial direction of the first through hole 323 is parallel to the axial direction of the second through hole 45. In the axial direction of the first through hole 323, the projection of the first through hole 323 overlaps at least partially with the projection of the second through hole 45. In this embodiment, the aperture diameter of the second through hole 45 is not limited and may be larger than, equal to, or smaller than the aperture diameter of the first through hole 323.

[0247] In this embodiment, by installing the second through hole 45 opposite to the first through hole 323 in the current collector component 40, the blockage of the electrolyte in the current collector component 40 during the liquid injection process is reduced, and the electrolyte can flow smoothly into the case 20, thereby improving the infiltration efficiency of the electrode assembly 10.

[0248] In some embodiments, in the axial direction of the first through hole 323, the projection of the first through hole 323 is located within the projection of the second through hole 45. In this embodiment, it is possible to avoid the current collector component 40 shielding the first through hole 323, and the electrolyte can flow smoothly into the case 20.

[0249] The first through hole 323 and the second through hole 45 are coaxially installed, and the aperture diameter of the second through hole 45 may be equal to or larger than the aperture diameter of the first through hole 323.

[0250] In some embodiments, the electrode assembly 10 has a wound structure. The electrode assembly 10 has a third through hole 14 at the winding center. The third through hole 14 penetrates the electrode assembly 10. The third through hole 14 is installed opposite to the first through hole 323 and the second through hole 45, and the electrolytic solution can flow into the inside of the electrode assembly 10 through the third through hole 14.

[0251] The electrode assembly 10 is made by winding a first electrode plate, a second electrode plate and a separator with a winding tool. After winding and forming, the winding tool is pulled out from the electrode assembly 10. After pulling out the winding tool, a third through hole 14 is formed in the middle of the electrode assembly 10.

[0252] The axial direction of the third through hole 14 may be parallel to the axial direction of the first through hole 323. The axis of the third through hole 14 coincides with the central axis A of the electrode assembly 10. The third through hole 14 penetrates the first tab 11, the body portion 12 and the second tab 13.

[0253] In the liquid injection process, the electrolytic solution can flow into the third through hole 14 through the first through hole 323 and the second through hole 45. The electrolytic solution flowing into the third through hole 14 infiltrates the electrode assembly 10 from the inside, and the infiltration efficiency of the electrode assembly 10 can be improved.

[0254] In some embodiments, in the axial direction of the third through hole 14, the projection of the second through hole 45 is located within the projection of the third through hole 14. In this way, the shielding of the first tab 11 with respect to the second through hole 45 can be reduced, and the electrolytic solution can flow smoothly into the third through hole 14.

[0255] In some embodiments, the first through hole 323, the second through hole 45, and the third through hole 14 are coaxially installed. The aperture of the third through hole 14 may be greater than or equal to the aperture of the second through hole 45.

[0256] In some embodiments, the first through hole 323 extends from the bottom wall of the concave groove 324 to the first inner surface 321 and penetrates the connecting portion 32. During liquid injection, the liquid injection head is pressed against the first outer surface 322, and the first outer surface 322 supports the liquid injection head, fits with the liquid injection head to achieve sealing, and can reduce the risk of electrolyte leakage to the outside of the battery cell 7.

[0257] FIG. 12 is a schematic structural diagram of an electrode assembly and a current collecting component of a battery cell according to some other embodiments of the present application.

[0258] As shown in FIG. 12, there are a plurality of third welding portions W3, and the plurality of third welding portions W3 are arranged at intervals along the circumferential direction Y of the first tab 11.

[0259] The third welding portion W3 may have a linear structure extending along the radial direction of the electrode assembly 10, a V-shaped structure, or of course, other structures.

[0260] The plurality of third welding portions W3 can increase the overcurrent area, improve the uniformity of the current density of the first electrode plate, reduce the internal resistance, and improve the overcurrent capacity.

[0261] FIG. 13 is a schematic local cross-sectional view of a battery cell according to some other embodiments of the present application, and FIG. 14 is an enlarged schematic view of the corner frame E in FIG. 13.

[0262] As shown in FIGS. 13 and 14, in some embodiments, the first portion 111 is welded to the current collecting component 40 to form the second welding portion W2.

[0263] The second welding portion W2 can reduce the contact resistance between the current collecting component 40 and the first tab 11 and improve the overcurrent capacity. The second welding portion W2 is close to the connecting portion 32, and by reducing the conductive path between the connecting portion 32 and the second welding portion W2, the resistance can be reduced and the overcurrent capacity can be improved.

[0264] In some embodiments, the first welding portion W1 and the second welding portion W2 are integrated. The current of the first tab 11 can conduct through the second welding portion W2 and the first welding portion W1 to the electrode terminal 30, thereby shortening the conductive path, reducing the resistance, and improving the overcurrent capacity.

[0265] In some embodiments, when welding the connecting portion 32 and the current collecting component 40, the current collecting component 40 melts and the first welding portion W1 and the second welding portion W2 can be formed.

[0266] FIG. 15 is an exploded schematic view of an electrode terminal of a battery cell according to some embodiments of the present application, and FIG. 16 is a top schematic view of an electrode terminal of a battery cell according to some embodiments of the present application.

[0267] Referring to FIGS. 13 to 16 together, in some embodiments, the case 20 includes a cylindrical body 21 and a lid body 22 connected to the cylindrical body 21. The cylindrical body 21 is installed to surround the outer periphery of the electrode assembly 10. An electrode lead-out hole 221 is provided in the lid body 22, and the electrode terminal 30 is attached to the electrode lead-out hole 221. The electrode terminal 30 includes a terminal body 34. The terminal body 34 includes a columnar portion 341, a first stopper portion 342, and a second stopper portion 343. At least a part of the columnar portion 341 is located within the electrode lead-out hole 221. The first recess 31 is provided in the columnar portion 341. Both the first stopper portion 342 and the second stopper portion 343 are connected to the outer wall of the columnar portion 341 and protrude from the outer wall of the columnar portion 341. The first stopper portion 342 and the second stopper portion 343 are respectively provided on the outer side and the inner side of the lid body 22 and are used to sandwich a part of the lid body 22.

[0268] The fact that the first stopper portion 342 is provided on the outer side of the lid body 22 means that the first stopper portion 342 is provided on the side of the lid body 22 away from the electrode assembly 10, and the fact that the second stopper portion 343 is provided on the inner side of the lid body 22 means that the second stopper portion 343 is provided on the side of the lid body 22 facing the electrode assembly 10.

[0269] In the thickness direction of the lid body 22, at least a part of the first stopper portion 342 overlaps the lid body 22, and at least a part of the second stopper portion 343 overlaps the lid body 22. The columnar portion 341 passes through the electrode lead-out hole 221 and connects the first stopper portion 342 and the second stopper portion 343 located on both sides of the lid body 22 respectively.

[0270] The first stopper portion 342 and the second stopper portion 343 sandwich a part of the lid body 22 from both sides to fix the terminal body 34 to the lid body 22. The first stopper portion 342 and the second stopper portion 343 may directly sandwich the lid body 22, or may indirectly sandwich the lid body 22 by other components.

[0271] Optionally, the columnar portion 341 is cylindrical. Both the first stopper portion 342 and the second stopper portion 343 are annular structures surrounding the columnar portion 341.

[0272] In some embodiments, the battery cell 7 further includes a first insulating component 60 and a second insulating component 70. At least a part of the first insulating component 60 is provided between the first stopper portion 342 and the lid body 22, and at least a part of the second insulating component 70 is provided between the second stopper portion 343 and the lid body 22. The first insulating component 60 and the second insulating component 70 are used to insulate and separate the terminal body 34 and the lid body 22.

[0273] Both the first insulating component 60 and the second insulating component 70 are annular structures installed so as to surround the columnar portion 341.

[0274] The first insulating component 60 can insulate and separate the first stopper portion 342 and the lid body 22, and the second insulating component 70 can insulate and separate the second stopper portion 343 and the lid body 22.

[0275] In some embodiments, one of the first insulating component 60 and the second insulating component 70 separates the columnar portion 341 from the cover body 22. For example, a part of the first insulating component 60 extends into the electrode lead-out hole 221 to separate the hole wall of the electrode lead-out hole 221 from the columnar portion 341.

[0276] In some embodiments, the first insulating component 60 and the second insulating component 70 are integrally formed. Instead, in some other embodiments, the first insulating component 60 and the second insulating component 70 are provided separately and abut against each other.

[0277] In some embodiments, one of the first insulating component 60 and the second insulating component 70 is used to seal the electrode lead-out hole 221. In some examples, the first stopper portion 342 and the cover body 22 extrude the first insulating component 60, and the first insulating component 60 is compressed to seal the electrode lead-out hole 221 from the outside. In some other examples, the second stopper portion 343 and the cover body 22 extrude the second insulating component 70, and the second insulating component 70 is compressed to seal the electrode lead-out hole 221 from the inside.

[0278] In some embodiments, the battery cell 7 further includes a sealing ring 80, and the sealing ring 80 is externally fitted to the columnar portion 341 and is used to seal the electrode lead-out hole 221. Optionally, a part of the sealing ring 80 extends into the electrode lead-out hole 221 to separate the hole wall of the electrode lead-out hole 221 from the columnar portion 341.

[0279] In some embodiments, a plurality of protrusion structures 342a are provided on the outer periphery of the first stopper portion 342, and the plurality of protrusion structures 342a are installed at intervals along the circumferential direction of the columnar portion 341.

[0280] Optionally, the plurality of protrusion structures 342a may be installed at intervals along the circumferential direction of the columnar portion 341 or the like.

[0281] The first stopper portion 342 has a burring structure formed by folding back the end portion away from the electrode assembly 10 of the terminal body 34 outwardly.

[0282] Before assembling the terminal body 34 into the case 20, the first stopper portion 342 of the terminal body 34 has a substantially cylindrical structure and is located at the upper end of the columnar portion 341. The outer wall of the first stopper portion 342 is flush with the outer wall of the columnar portion 341. When assembling the terminal body 34 and the case 20, after passing the first stopper portion 342 through the electrode lead-out hole 221, by extruding the first stopper portion 342, the first stopper portion 342 is folded back outwardly to caul the terminal body 34 to the lid body 22.

[0283] Before folding back the first stopper portion 342, a plurality of concave groove structures 342b are provided at intervals at the upper end of the first stopper portion 342. After folding back the first stopper portion 342, a plurality of protrusion structures 342a are formed at intervals along the circumferential direction of the columnar portion 341, and between adjacent protrusion structures 342a are the concave groove structures 342b. In this embodiment, by providing the concave groove structures 342b and the protrusion structures 342a, the difficulty of folding back the first stopper portion 342 is reduced, and the stress concentration on the first stopper portion 342 is reduced.

[0284] In some embodiments, the second stopper portion 343 is a stopper structure formed by extruding the end portion of the terminal body 34 toward the electrode assembly 10 so that the end portion of the terminal body 34 toward the electrode assembly 10 extends outward. When assembling the lid body 22 and the terminal body 34, an external device can extrude the end portion of the terminal body 34 toward the electrode assembly 10, and the end portion of the terminal body 34 toward the electrode assembly 10 extends outward under the action of pressure to form the protruding second stopper portion 343.

[0285] In some embodiments, the terminal body 34 has a second outer surface 344, and the first recess 31 is recessed from the second outer surface 344 along the direction toward the electrode assembly 10 to the first outer surface 322 of the connection portion 32.

[0286] The terminal body 34 has a second outer surface 344 and a second inner surface 345 that are disposed opposite to each other. The second inner surface 345 faces the electrode assembly 10, and the second outer surface 344 faces away from the electrode assembly 10. The first recess 31 is recessed from the second outer surface 344 along the direction toward the electrode assembly 10 to the first outer surface 322 of the connection portion 32.

[0287] In some embodiments, the electrode terminal 30 further includes a seal plate 33 that is connected to the terminal body 34 and seals the opening of the first recess 31.

[0288] The seal plate 33 may be entirely located outside the first recess 31, or may be partially accommodated within the first recess 31, as long as the seal plate 33 can seal the opening of the first recess 31.

[0289] The seal plate 33 can protect the connection portion 32 from the outside, reduce external impurities entering the first recess 31, reduce the risk of the connection portion 32 being damaged by external impurities, and improve the sealing performance of the battery cell 7.

[0290] Also, the seal plate 33 can also serve to seal the first through hole 323. After the battery cell 7 is formed, the seal plate 33 can reduce the risk of the electrolyte leaking through the first through hole 323 and the first recess 31, and improve the sealing performance.

[0291] In some embodiments, a stepped surface 311 is provided on the side wall of the first recess 31, at least a part of the seal plate 33 is accommodated in the first recess 31, and the stepped surface 311 is used to support the seal plate 33.

[0292] The first recess 31 is a stepped recess with a large outer part and a small inner part.

[0293] When assembling the seal plate 33, the stepped surface 311 can simplify the assembly process by supporting and positioning the seal plate 33. At least a part of the seal plate 33 is received in the first recess 31, thus reducing the size of the entire electrode terminal 30, reducing the space occupied by the electrode terminal 30, and improving the energy density.

[0294] In some embodiments, the seal plate 33 is welded to the side wall of the first recess 31 to seal the opening of the first recess 31.

[0295] In some embodiments, a gap is provided between the seal plate 33 and the connection part 32 to avoid the first welding part W1.

[0296] The surface of the first welding part W1 has irregularities. When the seal plate 33 is pressed against the first welding part W1, the seal plate 33 rattles during the assembly process, affecting the sealing effect. In this embodiment, by providing a gap between the seal plate 33 and the connection part 32, the seal plate 33 avoids the first welding part W1, preventing direct contact between the seal plate 33 and the first welding part W1, reducing the rattling of the seal plate 33 during the assembly process, and ensuring the sealing effect.

[0297] In some examples, the first recess 31 has a stepped structure. In this way, the seal plate 33 abuts against the stepped surface 311 to form a gap between the seal plate 33 and the connection part 32. In some other examples, the connection part 32 may be provided with a stepped structure. In this way, the seal plate 33 abuts against the connection part 32, and the concave groove 324 of the connection part 32 may form a gap between the seal plate 33 and the connection part 32.

[0298] In some embodiments, the seal plate 33 may be used to be welded to the bus bar member of the battery. In the battery, the bus bar member may connect the seal plate 33 of one battery cell 7 and the lid 22 of another battery cell 7 to connect these two battery cells 7 in series.

[0299] In some embodiments, at least a part of the seal plate 33 protrudes from the second outer surface 344 of the terminal body 34.

[0300] When it is necessary to weld the bus bar member and the seal plate 33, first, the bus bar member is attached to the upper surface of the seal plate 33 (i.e., the outer surface away from the connection portion 32 of the seal plate 33), and then the bus bar member and the seal plate 33 are welded.

[0301] At least a part of the seal plate 33 protrudes from the second outer surface 344, avoiding interference with the attachment of the seal plate 33 and the bus bar member by the second outer surface 344, and ensuring that the bus bar member is in close contact with the seal plate 33.

[0302] In some embodiments, the connection portion 32 is provided at the end of the terminal body 34 facing the electrode assembly 10, and the first inner surface 321 of the connection portion 32 is flush with the second inner surface 345.

[0303] The second inner surface 345 is the surface of the terminal body 34 facing the electrode assembly 10. The first inner surface 321 of the connection portion 32 constitutes a part of the second inner surface 345. In this way, the terminal body 34 can be fitted into the current collecting component 40 having a flat plate structure. In this embodiment, by simply attaching the current collecting component 40 to the second inner surface 345, the attachment of the connection portion 32 and the current collecting component 40 can be realized, and the welding of the connection portion 32 and the current collecting component 40 can be easily realized.

[0304] FIG. 17 is a schematic partial cross-sectional view of a battery cell according to some other embodiments of the present application.

[0305] As shown in FIG. 17, in some embodiments, the terminal body 34 has a second outer surface 344 and a second inner surface 345 that are disposed opposite to each other, and the first recess 31 recesses from the second outer surface 344 to the first outer surface 322 of the connection portion 32 along the direction toward the electrode assembly 10. The terminal body 34 further includes a third recess 35, and the third recess 35 recesses from the second inner surface 345 to the first inner surface 321 of the connection portion 32 along the direction away from the electrode assembly 10.

[0306] In the embodiments of the present application, by simultaneously providing the first recess 31 and the third recess 35, the thickness of the connection portion 32 can be reduced, thus reducing the requirement for the depth of the first recess 31 and simplifying the molding process. By providing the third recess 35, the internal space of the battery cell 7 can be enlarged and the energy density can be improved.

[0307] In some embodiments, the current collecting component 40 includes a terminal connection portion 46 and a tab connection portion 47 surrounding the outside of the terminal connection portion 46. The terminal connection portion 46 protrudes from the tab connection portion 47 such that the top of the terminal connection portion 46 abuts against the first inner surface 321 of the connection portion 32 and enters into the third recess 35.

[0308] The tab connection portion 47 is located between the lid body 22 and the first tab 11 and is welded to the second portion 112 to form a third weld portion W3. Optionally, the tab connection portion 47 may have an annular flat plate structure.

[0309] In some embodiments, a fourth recess 48 is provided at a position corresponding to the terminal connection portion 46 of the current collecting component 40, and the fourth recess 48 recesses with respect to the surface of the tab connection portion 47 facing the first tab 11. The fourth recess 48 can reduce the space occupied by the terminal connection portion 46 and reduce the weight of the current collecting component 40. Exemplarily, the terminal connection portion 46 and the fourth recess 48 are formed by pressing the current collecting component 40.

[0310] FIG. 18 is a schematic partial cross-sectional view of a battery cell according to some other embodiments of the present application.

[0311] As shown in FIG. 18, in some embodiments, the terminal body 34 has a second outer surface 344 and a second inner surface 345 that are disposed opposite to each other, and the first recess 31 is recessed from the second inner surface 345 along a direction away from the electrode assembly 10 to the first inner surface 321 of the connection portion 32.

[0312] In this embodiment, by installing the first recess 31 inside the terminal body 34, the flatness and area of the second outer surface 344 can be ensured, and it is possible to facilitate the connection of the terminal body 34 to an external bus bar member. By installing the first recess 31 inside the terminal body 34, the internal space of the battery cell 7 can be increased, and the energy density can be improved.

[0313] In some embodiments, the current collecting component 40 includes a terminal connection portion 46 and a tab connection portion 47 that surrounds the outside of the terminal connection portion 46. The terminal connection portion 46 protrudes from the tab connection portion 47 so that the top of the terminal connection portion 46 abuts against the first inner surface 321 of the connection portion 32 and enters the first recess 31.

[0314] The tab connection portion 47 is located between the lid body 22 and the first tab 11 and is welded to the second portion 112 to form a third weld portion W3. Optionally, the tab connection portion 47 may have an annular flat plate structure.

[0315] In some embodiments, a fourth recess 48 is installed at a position corresponding to the terminal connection portion 46 of the current collecting component 40, and the fourth recess 48 is recessed with respect to the surface facing the first tab 11 of the tab connection portion 47. The fourth recess 48 can reduce the space occupied by the terminal connection portion 46 and reduce the weight of the current collecting component 40. Exemplarily, the terminal connection portion 46 and the fourth recess 48 are formed by pressing the current collecting component 40.

[0316] FIG. 19 is a schematic cross-sectional view of a battery cell according to some other embodiments of the present application.

[0317] As shown in FIG. 19, in some embodiments, the battery cell 7 may be a rectangular battery cell.

[0318] In some embodiments, the case 20 includes a cylindrical body 21 and a lid 22 formed integrally, and the cylindrical body 21 is installed to surround the outer periphery of the electrode assembly 10. Exemplarily, the cylindrical body 21 may be a rectangular cylinder.

[0319] An opening is provided at an end of the cylindrical body 21 away from the lid 22, and a cover plate 50 is placed over the opening of the cylindrical body 21 to seal the opening of the cylindrical body 21. Exemplarily, the cover plate 50 is welded to the cylindrical body 21.

[0320] In some embodiments, the battery cell further includes a first electrode terminal 30 and a second electrode terminal 90 with opposite polarities. The first electrode terminal 30 is used to be electrically connected to the first tab of the electrode assembly 10, and the second electrode terminal 90 is used to be electrically connected to the second tab of the electrode assembly 10.

[0321] In some embodiments, both the first electrode terminal 30 and the second electrode terminal 90 are attached to the lid 22.

[0322] In a battery, the bus bar member is connected to the electrode terminals of a plurality of battery cells to connect the plurality of battery cells in series, in parallel, or in series-parallel. Both the first electrode terminal 30 and the second electrode terminal 90 may be used to be connected to the bus bar member.

[0323] When the battery is subjected to an external impact, the bus bar member pulls the lid 22 by the first electrode terminal 30 and the second electrode terminal 90, and a force acts on the connection portion between the lid 22 and the cylindrical body 21. When the lid 22 and the cylindrical body 21 are of a separate structure, for example, when the lid 22 and the cylindrical body 21 are connected by welding, the connection portion between the lid 22 and the cylindrical body 21 may fail due to the action of the force. The embodiments of the present application improve the strength of the connection portion between the lid 22 and the cylindrical body 21 by integrally installing the lid 22 and the cylindrical body 21, and reduce the risk of the connection between the lid 22 and the cylindrical body 21 failing.

[0324] In some embodiments, the case 20 is not electrically connected to the positive electrode of the electrode assembly and is not electrically connected to the negative electrode of the electrode assembly either. In other words, the case 20 is not charged.

[0325] In some embodiments, the first tab and the second tab of the electrode assembly 10 are located on the same side facing the cover 22 of the electrode assembly.

[0326] According to some embodiments of the present application, a battery is further provided, and this battery includes a battery cell of any one of the above embodiments.

[0327] According to some embodiments of the present application, a power consumption device is further provided, and this power consumption device includes a battery of any one of the above embodiments, and the battery is used to provide electrical energy to the power consumption device. The power consumption device may be any one of the devices or systems applying the battery cell.

[0328] Referring to FIGS. 4 to 6, according to some embodiments of the present application, a cylindrical battery cell 7 is provided, and this cylindrical battery cell 7 includes an electrode assembly 10, a case 20, an electrode terminal 30, a current collecting component 40, and a cover plate 50.

[0329] The case 20 includes a cylindrical body 21 and a cover 22 formed integrally. The cylindrical body 21 is installed to surround the outer periphery of the electrode assembly 10. An electrode lead-out hole 221 is provided in the cover 22, and the electrode terminal 30 is attached to the electrode lead-out hole 221. An opening is provided at the end of the cylindrical body 21 away from the cover 22, and the cover plate 50 is placed over the opening of the cylindrical body 21 to seal the opening of the cylindrical body 21.

[0330] The electrode assembly 10 includes a main body 12, a first tab 11, and a second tab 13. The first tab 11 and the second tab 13 protrude from the main body 12. The first tab 11 is located at the end of the electrode assembly 10 facing the electrode terminal 30, and the second tab 13 is located at the end of the electrode assembly 10 away from the electrode terminal 30.

[0331] The electrode terminal 30 includes a terminal body 34 and a seal plate 33. The terminal body 34 includes a first recess 31 and a connection portion 32 located at the bottom of the first recess 31. The seal plate 33 is connected to the terminal body 34 and seals the opening of the first recess 31.

[0332] The current collecting component 40 is welded to the first tab 11 and the connection portion 32 to electrically connect the first tab 11 and the connection portion 32.

[0333] It should be noted that, as long as there is no contradiction, the embodiments and the features in the embodiments in this application can be combined with each other.

[0334] Finally, it should be noted that the above embodiments are only for explaining the technical solution of this application and do not limit it. Although this application has been described in detail with reference to the above embodiments, those skilled in the art can still modify the technical solutions described in the above embodiments or make equivalent substitutions for some of their technical features. It should be understood that these modifications or substitutions do not deviate from the spirit and scope of the technical solutions of the embodiments of this application from the gist of the corresponding technical solutions.

Claims

1. A battery cell, comprising: An electrode assembly including a first tab; A case for housing the electrode assembly; An electrode terminal installed on the case and including a first recess and a connection portion located at the bottom of the first recess; A current collecting component connected to the first tab and welded to the connection portion; The case includes a cylindrical body and a lid connected to the cylindrical body. The cylindrical body is installed to surround the outer periphery of the electrode assembly. An electrode lead-out hole is provided in the lid, and the electrode terminal is attached to the electrode lead-out hole. The lid and the cylindrical body are integrally formed. An end of the case away from the electrode terminal has an opening, and the battery cell further includes a cover plate for sealing the opening. The electrode assembly further includes a second tab having a polarity opposite to that of the first tab. The second tab is installed around the central axis of the electrode assembly. The first tab is provided at an end of the electrode assembly facing the electrode terminal, and the second tab is provided at an end of the electrode assembly facing the cover plate. The second tab is electrically connected to the case. A battery cell.

2. The current collecting component is welded to the connection portion to form a first welding portion. In the thickness direction of the connection portion, the first welding portion extends from the side of the connection portion away from the current collecting component to at least inside the current collecting component. The battery cell according to claim 1.

3. In the thickness direction of the connection portion, the first welding portion does not protrude beyond the surface of the current collecting component away from the connection portion. The battery cell according to claim 2.

4. The first welding portion and the lid are both annular. The outer diameter of the lid is D ０ and the inner diameter of the first welding portion is D １ and D １ and D ０ satisfies 0.1 ≦ D １ / D ０ ≦ 0.6, the battery cell according to claim 2.

5. The first welded portion has a non-closed structure, and the central angle of the first welded portion is 180° to 330°, the battery cell according to claim 4.

6. The first welded portion has a closed structure, the battery cell according to claim 4.

7. 0.2 ≦ D １ / D ０ ≦ 0.4, the battery cell according to claim 4.

8. D １ is 5 mm to 14 mm, the battery cell according to claim 4.

9. In the thickness direction of the connection portion, the size of the first welded portion is h, and the thickness of the region for welding the connection portion to the current collector component is d ０ where d ０ and h satisfy 1 < h / d ０ ≦ 1.5, the battery cell according to claim 2.

10. The thickness of the region for welding the connection portion to the current collector component is d １ where d ０ and d １ satisfy 0.5 ≦ d １ / d ０ ≦ 1.2, the battery cell according to claim 9.

11. d ０ is 0.4 mm to 1.2 mm, the battery cell according to claim 9.

12. At least a part of the first tab is located on the side away from the electrode terminal of the current collector component and is supported by the current collector component, the battery cell according to claim 1.

13. The first portion of the first tab is located on the side away from the first recess of the connecting portion and is used to support the portion of the current collecting component facing the connecting portion. The battery cell according to claim 12.

14. The first portion is welded to the current collecting component to form a second welding portion. The battery cell according to claim 13.

15. The second portion of the first tab surrounds the outer periphery of the first portion and is used to support the region of the current collecting component that does not face the connecting portion. The battery cell according to claim 13.

16. The second portion is welded to the current collecting component to form a third welding portion. The battery cell according to claim 15.

17. The side of the current collecting component facing the first tab has a convex portion, and the convex portion is welded to the second portion to form the third welding portion. The battery cell according to claim 16.

18. The first tab is installed around the central axis of the electrode assembly, and the cross-section perpendicular to the central axis of the first tab is an annular shape. The outer radius of the first tab is R, and the minimum pitch between the third welding portion and the central axis in the radial direction of the first tab is D. ２ Yes, both satisfy 0.2 ≤ D. ２ / R ≤ 0.

8. The battery cell according to claim 16.

19. D ２ and R satisfy 0.2 ≤ D. ２ / R ≤ 0.

5. The battery cell according to claim 18.

20. D ２ is 3.5 mm to 10 mm. The battery cell according to claim 18.

21. The diameter of the current collecting component is D. ３ The diameter of the first tab is D. ４ Yes, D ３ is D. ４The battery cell according to claim 12, which is smaller than...

22. D ３ and D ４ satisfies 0.75 ≤ D ３ / D ４ ≤ 0.97, the battery cell according to claim 21.

23. D ３ is 35 mm to 44 mm, the battery cell according to claim 21.

24. In the connection part, a concave groove recessed along the direction from the first outer surface of the connection part toward the electrode assembly is provided, and the first welding part extends from the bottom wall of the concave groove to at least the inside of the current collecting component. The battery cell according to claim 2.

25. The electrode terminal includes a terminal body, the terminal body includes a columnar part, a first stopper part, and a second stopper part. At least a part of the columnar part is located in the electrode lead-out hole. The first concave part is provided in the columnar part. Both the first stopper part and the second stopper part are connected to the outer side wall of the columnar part and protrude from the outer side wall of the columnar part. The first stopper part and the second stopper part are respectively provided on the outer side and the inner side of the lid body and are used to sandwich a part of the lid body. The battery cell according to claim 1.

26. The terminal body has a second outer surface, and the first concave part recesses from the second outer surface to the first outer surface of the connection part along the direction toward the electrode assembly. The battery cell according to claim 25.

27. The electrode terminal further includes a seal plate connected to the terminal body and sealing the opening of the first concave part. The battery cell according to claim 25.

28. The second tab is a negative electrode tab, and the base material of the case is steel. The battery cell according to claim 1.

29. A battery including the battery cell according to any one of claims 1 to 28. Claim 30 A power consumption device including the battery according to claim 29, wherein the battery is used to provide electrical energy.

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