Battery cell and manufacturing method therefor, battery and electric device

Abstract

The present application relates to a battery cell and a manufacturing method therefor, a battery and an electric device. The manufacturing method comprises: providing electrode assemblies, wherein each electrode assembly comprises tabs; providing current-collecting members, each current-collecting member comprising tab connecting portions and a current-collecting body, and ultrasonically welding the tab connecting portions to the tabs, wherein the step of providing current-collecting members comprises: providing a sheet, and extruding the sheet to increase the roughness of the surface of a pressed region of the sheet, the pressed region at least forming the tab connecting portions configured to be connected to the tabs, and the roughness of the surfaces of the tab connecting portions facing the tabs being greater than the roughness of the surface of the current-collecting body facing the tabs; and providing a case and electrode terminals disposed on the case, connecting the current-collecting members to the electrode terminals, and mounting the electrode assemblies in the case. The manufacturing method provided in the present application can increase, by means of extrusion, the roughness of the surfaces of the tab connecting portions facing the tabs, thereby improving the strength of connection between the current-collecting members and the tabs, and thus improving the stability of connection between the current-collecting members and the tabs.

Description

Battery cell and manufacturing method thereof, battery and electric device

[0001] Cross-reference to Related Applications

[0002] This application claims priority to Chinese Patent Application No. 202410424898.9, filed on April 10, 2024, entitled “Battery cell and manufacturing method thereof, battery and electric device”, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0003] The present application relates to the technical field of battery production, in particular to a battery cell and manufacturing method thereof, a battery and an electric device. BACKGROUND

[0004] Battery cells are widely used in electronic devices, such as mobile phones, notebook computers, electric vehicles, electric cars, electric planes, electric ships, electric toy cars, electric toy ships, electric toy planes, electric tools, and the like. Battery cells can include cadmium-nickel battery cells, hydrogen-nickel battery cells, lithium-ion battery cells, and secondary alkaline zinc-manganese battery cells, etc.

[0005] In the development of battery technology, how to improve the reliability of battery cells is a technical problem that needs to be solved in battery technology.

[0006] SUMMARY

[0007] The present application provides a battery cell and manufacturing method thereof, a battery and an electric device, which can improve the reliability of battery cells to some extent.

[0008] In a first aspect, the present application provides a manufacturing method of a battery cell, comprising:

[0009] providing an electrode assembly, the electrode assembly comprising a tab;

[0010] providing a current collecting member, the current collecting member comprising a tab connecting portion and a current collecting body, ultrasonic welding the tab connecting portion with the tab,

[0011] wherein the providing the current collecting member comprises: providing a sheet, extruding the sheet to increase the roughness of the surface of a pressed area of the sheet, the pressed area at least forming the tab connecting portion for connecting with the tab, the roughness of the surface of the tab connecting portion facing the tab being greater than the roughness of the surface of the current collecting body facing the tab;

[0012] providing a housing and an electrode terminal arranged in the housing, connecting the current collecting member with the electrode terminal, and installing the electrode assembly into the housing.

[0013] The manufacturing method of the battery cell provided in the application improves the manufacturing method of the current collecting member, increases the roughness of the tab connecting part connected with the tab of the electrode assembly by extruding the sheet, increases the connection strength of the electrode assembly and the tab by increasing the roughness of the surface of the tab connecting part facing the tab, and provides the connection stability of the two. Moreover, the extrusion process is combined with the manufacturing process of the original current collecting member, the manufacturing cost of the current collecting member is reduced under the premise of increasing the roughness of the tab connecting part, and the manufacturing process of the current collecting member is simplified. In addition, the oil stains on the surface of the tab connecting part can be removed to some extent by roughening the surface of the tab connecting part facing the tab, thereby reducing the probability of false welding of the current collecting member and the tab, and improving the reliability of the battery cell.

[0014] According to one embodiment of the application, the step of extruding the sheet to increase the roughness of the surface of the pressed area of the sheet comprises:

[0015] The sheet is extruded for the first time, and the sheet forms a first pressed area;

[0016] The sheet is extruded for the second time, and the sheet forms a second pressed area;

[0017] Among them, one of the first pressed area and the second pressed area forms a terminal connecting part for connecting with the electrode terminal, and the other forms a tab connecting part for connecting with the tab.

[0018] In these optional embodiments, the extrusion process is combined with the extrusion process in the original manufacturing process of the current collecting member, without additional other processes for manufacturing the current collecting member, and without affecting the normal process flow of the current collecting member production.

[0019] According to one embodiment of the application, the first extrusion and the second extrusion are performed synchronously.

[0020] In these optional embodiments, the manufacturing process of the current collecting member is optimized in this way.

[0021] According to one embodiment of the application, the manufacturing method further comprises: stamping the sheet to form a protruding convex part and a concave part corresponding to the position of the convex part on the sheet; and the step of extruding the sheet to increase the roughness of the surface of the pressed area of the sheet comprises: extruding the bottom surface of the concave part.

[0022] In these optional embodiments, the risk of welding through of the current collecting member and the electrode terminal can be reduced, the welding success rate can be improved, and the phenomenon of laser high reflection during welding can also be effectively improved.

[0023] According to one embodiment of the application, the roughness Ra of the surface of the tab connecting part facing the tab is 1-5 μm.

[0024] In these alternative embodiments, the surface of the tab connecting portion facing the tab has a suitable roughness Ra, reducing the occurrence of overwelding of the tab connecting portion and the tab, and further improving the connection strength of the electrode assembly and the current collecting member.

[0025] According to one embodiment of the present application, the energy of the ultrasonic welding is 260J-380J.

[0026] In these alternative embodiments, the lower energy of the ultrasonic welding not only reduces the manufacturing cost of the battery cell, but also realizes high-strength connection of the electrode assembly and the current collecting member.

[0027] According to one embodiment of the present application, the amplitude of the ultrasonic welding is 25μm-55μm.

[0028] In these alternative embodiments, the ultrasonic welding has a suitable amplitude, the surface of the tab and the tab connecting portion rub against each other to form a molecular layer fusion, improving the stability of the welded connection.

[0029] According to one embodiment of the present application, the pressure of the ultrasonic welding is 25Psi-45Psi.

[0030] In these alternative embodiments, the ultrasonic welding reduces the gap between the tab and the tab connecting portion by applying a suitable pressure, improving the welding strength of the tab and the tab connecting portion.

[0031] According to one embodiment of the present application, the terminal connecting portion and the electrode terminal are laser welded.

[0032] In these alternative embodiments, such arrangement can improve the connection strength and stability between the electrode terminal and the current collecting member.

[0033] In a second aspect, the present application provides a battery cell manufactured by the manufacturing method described above.

[0034] The battery cell provided by the present application is manufactured by the manufacturing method described above, the roughness of the surface of the tab connecting portion facing the tab is greater than the roughness of the surface of the current collecting body facing the tab, the tab connecting portion is welded to the tab, by increasing the roughness of the surface of the tab connecting portion, better welding effect can be achieved under lower welding parameters, which can not only improve the stability of the welding of the current collecting member and the electrode assembly, but also reduce the welding cost. At the same time, it can also reduce the problem of virtual welding, and improve the reliability of the battery cell.

[0035] According to one embodiment of the present application, the battery cell comprises a housing, an electrode terminal, an electrode assembly, and a current collecting member; the electrode terminal is arranged in the housing; the electrode assembly is accommodated in the housing, and the electrode assembly comprises a tab; the current collecting member is used for connecting the electrode terminal and the tab, and the current collecting member comprises a current collecting body and a tab connecting portion, the tab connecting portion is connected to the current collecting body, and the tab connecting portion is used for connecting the tab.

[0036] According to one embodiment of the present application, the current collecting member further comprises a terminal connecting portion, the terminal connecting portion is connected to the current collecting body, and the terminal connecting portion is used for connecting the electrode terminal.

[0037] In a third aspect, the present application provides a battery comprising the battery cell according to the foregoing.

[0038] In a fourth aspect, the present application provides an electric device comprising the battery according to the foregoing, and the battery is used for providing electric energy.

[0039] The above description is only a summary of the technical solutions of the present application. In order to enable the technical means of the present application to be more clearly understood, and to be implemented according to the content of the description, and in order to enable the above and other purposes, characteristics and advantages of the present application to be more obvious and easy to understand, the specific implementation manner of the present application is described below. BRIEF DESCRIPTION OF DRAWINGS

[0040] The features, advantages, and technical effects of the exemplary embodiments of the present application will be described below with reference to the accompanying drawings.

[0041] FIG. 1 is a structural schematic diagram of a vehicle according to an embodiment of the present application;

[0042] FIG. 2 is a structural schematic diagram of a battery according to an embodiment of the present application;

[0043] FIG. 3 is a manufacturing process flow diagram of a battery cell according to some embodiments of the present application;

[0044] FIG. 4 is a structural schematic diagram of a battery cell according to an embodiment of the present application;

[0045] FIG. 5 is a structural schematic diagram of a current collecting member according to some embodiments of the present application;

[0046] FIG. 6 is a structural schematic diagram of a current collecting member according to some other embodiments of the present application;

[0047] FIG. 7 is a structural schematic diagram of a terminal connecting portion of a current collecting member according to some embodiments of the present application;

[0048] FIG. 8 is a test result of the battery cell of embodiments 1 to 7 and comparative examples 1 to 7 of the present application.

[0049] The accompanying drawings are not necessarily drawn to scale.

[0050] Explanation of reference signs:

[0051] 1000 vehicle; 100 battery; 200 controller; 300 motor; 10 battery cell; 20 first case; 30 second case; 1 current collecting member; 11 current collecting body; 12 tab connecting portion; 13 terminal connecting portion; 2 housing; 3 electrode terminal; 4 electrode assembly; 41 tab. DETAILED DESCRIPTION

[0052] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0053] Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs; the terms used in the present application are only for the purpose of describing the specific embodiments of the present application and are not intended to limit the present application; the terms "include" and "have" and any variations thereof in the specification and claims of the present application and the above description of drawings are intended to cover non-exclusive inclusion. The terms "first", "second" and the like in the specification and claims of the present application and the above description of drawings are used to distinguish different objects, and are not intended to describe a particular order or primary and secondary relationship.

[0054] In the present application, the phrase "embodiment" means that the specific features, structures or characteristics described in connection with the embodiment can be included in at least one embodiment of the present application. The appearance of this phrase at various places in the specification does not necessarily mean the same embodiment, nor is it an independent or alternative embodiment to other embodiments.

[0055] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mount", "connect", "connection", "attach" should be understood broadly, for example, can be fixedly connected, can be detachably connected, or integrally connected; can be directly connected, or indirectly connected through an intermediate medium; can be internal communication of two elements. For a person of ordinary skill in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0056] The term "and / or" in the present application is only used to describe the relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which means that there are three cases of A alone, A and B together, and B alone. In addition, the character " / " in the present application generally represents an "or" relationship between the front and rear associated objects.

[0057] In the embodiments of the present application, the same reference signs represent the same components, and for the sake of brevity, the detailed description of the same components is omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, and the overall thickness, length, width and other dimensions of the integrated device are only exemplary and should not constitute any limitation on the present application.

[0058] "Multiple" appearing in the present application means two or more (including two).

[0059] In the embodiments of the present application, the battery cell can be a secondary battery cell, which means that the battery cell can be activated by charging after discharging to continue to be used.

[0060] The battery cell can be a lithium ion battery cell, a sodium ion battery cell, a sodium lithium ion battery cell, a lithium metal battery cell, a sodium metal battery cell, a lithium sulfur battery cell, a magnesium ion battery cell, a nickel hydrogen battery cell, a nickel cadmium battery cell, a lead-acid battery cell, etc. The embodiments of the present application are not limited thereto.

[0061] The battery cell generally includes an electrode assembly. The electrode assembly includes a positive electrode and a negative electrode. During the charging and discharging process of the battery cell, active ions (such as lithium ions) are inserted and extracted between the positive electrode and the negative electrode.

[0062] In some embodiments, the shape of the electrode assembly can be cylindrical, flat or multi-prismatic, etc.

[0063] In some embodiments, the electrode assembly is provided with a tab, which can guide the current out of the electrode assembly. The tab includes a positive tab and a negative tab.

[0064] In some embodiments, the battery cell can include a housing. The housing is used to package components such as the electrode assembly and the electrolyte. The housing can be a steel shell, an aluminum shell, a plastic shell (such as polypropylene), a composite metal shell (such as a copper-aluminum composite shell), or an aluminum-plastic film, etc.

[0065] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a soft-pack battery cell or other shaped battery cell, the prismatic battery cell includes a square cell, a blade-shaped cell, a multi-prismatic battery, such as a hexagonal prism battery, etc.

[0066] The battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity.

[0067] In some embodiments, the battery can be a battery module, and when there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0068] In some embodiments, the battery can be a battery pack, and the battery pack includes a box body and battery cells, and the battery cells or battery modules are accommodated in the box body.

[0069] In some embodiments, the box body can be part of the chassis structure of the vehicle. For example, part of the box body can be at least part of the floor of the vehicle, or part of the box body can be at least part of the cross beam and the longitudinal beam of the vehicle.

[0070] In the related art, during the manufacturing process of the battery cell, the electrode terminal in the end cover assembly needs to be connected with the electrode assembly. Generally, the tab of the electrode assembly and the electrode terminal provided on the end cover assembly are connected through the current collecting member, so that the current collecting member plays a role of adapter to realize the input or output of the electric energy of the battery cell. However, during the welding process of the current collecting member and the tab, the virtual welding condition may occur, which affects the tensile strength of the welding position of the current collecting member and the tab, thereby reducing the welding quality between the current collecting member and the electrode assembly and the reliability of the battery cell. The above statements are only used to provide background technical information related to the present application, and do not necessarily constitute the prior art.

[0071] In view of the above problems, the inventors have made in-depth research and proposed a manufacturing method of the battery cell provided in the present application. The manufacturing method of the current collecting member is improved. The sheet is extruded to make the tab connecting portion connected with the tab of the electrode assembly have a larger roughness. By increasing the roughness of the surface of the tab connecting portion facing the tab, the connection strength between the electrode assembly and the tab is increased, and the connection stability of the two is provided. Moreover, the extrusion process is combined with the manufacturing process of the original current collecting member. Under the premise of increasing the roughness of the tab connecting portion, the manufacturing cost of the current collecting member is reduced, and the manufacturing process of the current collecting member is simplified. In addition, by roughening the surface of the tab connecting portion facing the tab, the oil stains on the surface of the tab connecting portion can be removed to some extent, thereby reducing the probability of virtual welding of the current collecting member and the tab, and improving the reliability of the battery cell.

[0072] The battery can be applied to vehicles, mobile phones, portable devices, notebook computers, ships, spacecraft, electric toys and electric tools, etc. The vehicle can be a fuel automobile, a gas automobile or a new energy automobile, and the new energy automobile can be a pure electric automobile, a hybrid electric automobile or a range extended automobile, etc. The spacecraft includes an airplane, a rocket, a space shuttle and a spacecraft, etc. The electric toy includes a fixed or mobile electric toy, for example, a game machine, an electric automobile toy, an electric ship toy and an electric airplane toy, etc. The electric tool includes a metal cutting electric tool, a grinding electric tool, an assembling electric tool and a railway electric tool, for example, an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact electric drill, a concrete vibrator and an electric planer, etc. The above tab production equipment is not specially limited in the embodiment of the present application.

[0073] In some embodiments, the battery can be an energy storage device. The energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0074] The following embodiments are described for convenience with a vehicle as an example of an electric device in an embodiment of the present application.

[0075] Referring to FIG. 1, an embodiment of the present application provides a vehicle 1000. The vehicle 1000 can be a fuel automobile, a gas automobile or a new energy automobile. The new energy automobile can be a pure electric automobile, a hybrid electric automobile or a range extended automobile, etc. In an embodiment of the present application, the vehicle 1000 can include a motor 300, a controller 200 and a battery 100. The controller 200 is used to control the battery 100 to supply power to the motor 300. The motor 300 is connected to the wheels through a transmission mechanism, thereby driving the vehicle 1000 to travel. The battery 100 can be used as a driving power source of the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000. In one example, the battery 100 can be arranged at the bottom, the front or the rear of the vehicle 1000. The battery 100 can be used to supply power to the vehicle 1000. In one example, the battery 100 can be used as an operating power source of the vehicle 1000, for the circuit system of the vehicle 1000. For example, the battery 100 can be used for the working power demand of the vehicle 1000 during starting, navigation and running.

[0076] Please refer to FIG. 2, which is an exploded view of the battery 100 according to some embodiments of the present application. The battery 100 includes a box body and a battery cell. In some embodiments, the box body can include a first box body 20 and a second box body 30, the first box body 20 and the second box body 30 are mutually covered, and the first box body 20 and the second box body 30 together define a containing space for containing the battery cell. The second box body 30 can be a hollow structure with one end open, and the first box body 20 can be a plate-shaped structure, which covers the open side of the second box body 30 to make the first box body 20 and the second box body 30 together define the containing space; the first box body 20 and the second box body 30 can also be hollow structures with one side open, and the open side of the first box body 20 covers the open side of the second box body 30. Of course, the box body formed by the first box body 20 and the second box body 30 can have various shapes, such as a cylinder, a cuboid, etc.

[0077] In the battery 100, the battery cell can be multiple, and the multiple battery cells can be connected in series, in parallel, or in a mixed connection. The mixed connection means that there are both series connection and parallel connection among the multiple battery cells. The multiple battery cells can be directly connected in series, in parallel, or in a mixed connection, and then the whole of the multiple battery cells is contained in the box body; of course, the battery 100 can also be that the multiple battery cells are first connected in series, in parallel, or in a mixed connection to form a battery module, and then the multiple battery modules are connected in series, in parallel, or in a mixed connection to form a whole, which is contained in the box body. The battery 100 can also include other structures, for example, the battery 100 can also include a current collecting component for realizing the electrical connection between the multiple battery cells.

[0078] Each battery cell can be a lithium ion battery cell, a lithium-sulfur battery cell, a sodium ion battery cell, or a magnesium ion battery cell, but is not limited thereto. The battery cell can be in the shape of a cylinder, a flat body, a cuboid, or other shapes, etc.

[0079] Referring to FIGS. 3-6, FIG. 3 is a flow chart of a manufacturing process of a battery cell according to some embodiments of the present application; FIG. 4 is a structural schematic view of a battery cell according to an embodiment of the present application; FIG. 5 is a structural schematic view of a current collecting member according to some embodiments of the present application; and FIG. 6 is a structural schematic view of a current collecting member according to other embodiments of the present application.

[0080] In a first aspect, as shown in FIGS. 3-6, the present application provides a manufacturing method of a battery cell 10, comprising:

[0081] In step S100, an electrode assembly 4 is provided, the electrode assembly 4 including a tab 41.

[0082] Step S200, providing a current collecting member 1, the current collecting member 1 includes a tab connecting portion 12 and a current collecting body 11, and the tab connecting portion 12 is ultrasonic welded with the tab 41. Wherein, the providing of the current collecting member 1 includes: providing a sheet, extruding the sheet to increase the roughness of the surface of the pressed area of the sheet, the pressed area at least forms the tab connecting portion 12 for connecting with the tab 41, and the roughness of the surface of the tab connecting portion 12 facing the tab 41 is greater than the roughness of the surface of the current collecting body 11 facing the tab 41.

[0083] Step S300, providing a shell 2 and an electrode terminal 3 arranged on the shell 2, connecting the current collecting member 1 with the electrode terminal 3, and installing the electrode assembly 4 into the shell 2.

[0084] The electrode assembly 4 is a component in which an electrochemical reaction occurs in the battery cell 10, and can contain one or more electrode assemblies 4. Exemplarily, the electrode assembly 4 is mainly formed by winding a positive electrode tab and a negative electrode tab, the positive electrode tab and the negative electrode tab have a part of active material constituting the main body of the electrode assembly 4, and the part of the positive electrode tab and the negative electrode tab without active material each constitutes a tab 41. The positive and negative tabs can be located at one end of the main body together or at two ends of the main body respectively. In the charging and discharging process of the battery, the positive and negative active materials react with the electrolyte, and the tab 41 connects the electrode terminal 3 through the current collecting member 1 to form a current loop.

[0085] In the embodiment of the present application, as shown in FIGS. 5 and 6, the current collecting member 1 includes a current collecting body 11 and a tab connecting portion 12, the tab connecting portion 12 is connected to the current collecting body 11, the tab connecting portion 12 is used for connecting with the tab 41, and the roughness of the surface of the tab connecting portion 12 facing the tab 41 is greater than the roughness of the surface of the current collecting body 11 facing the tab 41. It can be understood that the surface of the current collecting body 11 facing the tab 41 is a smooth surface, and the surface of the tab connecting portion 12 facing the tab 41 is a rough surface; or, the surface of the current collecting body 11 facing the tab 41 and the surface of the tab connecting portion 12 facing the tab 41 are both rough surfaces, and the roughness of the current collecting body 11 is less than the roughness of the tab 41. By roughening the surface of the tab connecting portion 12 facing the tab 41, the connection stability of the current collecting member 1 and the tab 41 can be improved. Especially, when the current collecting member 1 and the tab 41 are welded, better welding effect can be achieved under lower welding process parameters, thereby increasing the connection strength of welding and reducing the defects of welding itself fluctuation.

[0086] Specifically, the current collecting member 1 includes two tab connecting portions 12, one connecting the positive tab and the other connecting the negative tab.

[0087] In the embodiments of the present application, the tab connecting portion 12 and the tab 41 are ultrasonic welded. Specifically, the ultrasonic welding is performed by transmitting high-frequency vibration waves to the surface of the tab connecting portion 12 and the tab 41 in contact with the welding head, and the tab connecting portion 12 and the tab 41 are welded. By roughening the surface of the tab connecting portion 12 facing the tab 41, the output power of the ultrasonic welding equipment can be reduced, and the service life of the ultrasonic welding equipment itself and the welding head seat can be increased. Roughening the surface of the tab connecting portion 12 facing the tab 41 can also satisfy the welding stability of the current collecting member 1 and the electrode assembly 4 under lower ultrasonic welding process conditions.

[0088] In the embodiments of the present application, the roughness of the surface of the pressed area of the sheet in step S200 can be increased by embossing the sheet to increase the roughness of the pressed area of the sheet. The pressed area after embossing forms the tab connecting portion 12, which is used to connect with the tab 41.

[0089] In some embodiments, the embossing process can use embossing rollers, embossing dies, embossing platen, and other embossing methods.

[0090] Specifically, the sheet is embossed by an embossing die to increase the roughness of the pressed area of the sheet. The shape of the embossing can be horizontal and vertical stripes, dot-shaped protrusions, geometric patterns, and the like.

[0091] It should be noted that the roughness of the surface of an object refers to the unevenness of the small pitch and small peaks and valleys of the processed surface. The distance between two wave peaks or two wave troughs (wave distance) is very small (below 1mm), which belongs to the micro-geometric error.

[0092] Optionally, the current collecting body 11 and the tab connecting portion 12 are integrally formed.

[0093] In some embodiments of the present application, the electrode terminal 3 and the electrode assembly 4 are respectively arranged on both sides of the current collecting member 1.

[0094] The electrode terminal 3 can be used to electrically connect with the electrode assembly 4 for outputting or inputting the electrical energy of the battery monomer 10.

[0095] Optionally, the current collecting member 1 and the electrode terminal 3 are connected by welding, and the electrode assembly 4 and the electrode terminal 3 are connected by welding. The two connection methods can be the same or different.

[0096] Specifically, the electrode terminal 3 and the electrode assembly 4 are arranged in a spaced manner along the first direction, the current collecting member 1 is arranged in an inclined manner along the first direction between the electrode terminal 3 and the electrode assembly 4, the current collecting body 11 is connected with the tab connecting portion 12, the tab connecting portion 12 is connected with the tab 41 of the electrode assembly 4, and the end of the current collecting body 11 away from the tab connecting portion 12 is connected with the electrode terminal 3.

[0097] The manufacturing method of the battery cell 10 provided in the present application improves the manufacturing method of the current collecting member 1, and increases the roughness of the tab connecting portion 12 connected with the tab 41 of the electrode assembly 4 by extruding the sheet, so as to increase the connection strength between the electrode assembly 4 and the tab 41, and provide the connection stability of the two. Moreover, the extrusion process is combined with the manufacturing process of the original current collecting member 1, and the manufacturing cost of the current collecting member 1 is reduced under the premise of increasing the roughness of the tab connecting portion 12, and the manufacturing process of the current collecting member 1 is simplified. In addition, by roughening the surface of the tab connecting portion 12 facing the tab 41, the oil stains on the surface of the tab connecting portion 12 can be removed to some extent, so as to reduce the probability of false welding between the current collecting member 1 and the tab 41, and improve the reliability of the battery cell 10.

[0098] According to one embodiment of the present application, the step of extruding the sheet to increase the roughness of the surface of the pressed area of the sheet comprises:

[0099] The sheet is extruded for the first time, and the sheet forms a first pressed area;

[0100] The sheet is extruded for the second time, and the sheet forms a second pressed area;

[0101] Among them, one of the first pressed area and the second pressed area forms a terminal connecting portion 13 for connecting with the electrode terminal 3, and the other forms a tab connecting portion 12 for connecting with the tab 41.

[0102] In the embodiment of the present application, the sheet is extruded for the first time and the second time to form the terminal connecting portion 13 and the tab connecting portion 12 on the sheet, and the area not extruded is the current collecting body 11. The tab connecting portion 12 is used for connecting with the tab 41, and the terminal connecting portion 13 is used for connecting with the electrode terminal 3.

[0103] In some embodiments, the first extrusion and the second extrusion can be extruded at the same time.

[0104] In some embodiments, the first extrusion is performed first to form the first pressed area, and the first pressed area is the terminal connecting portion 13; and then the second extrusion is performed to form the second pressed area, and the second pressed area is the tab connecting portion 12.

[0105] In the embodiment of the present application, the extrusion methods of the first extrusion and the second extrusion can be the same or different, for example, the first extrusion and the second extrusion are both extruded by using an embossing die, or the first extrusion is extruded by using an embossing roller and the second extrusion is extruded by using an embossing die.

[0106] Specifically, the current collecting member 1 includes a current collecting body 11, a terminal connecting portion 13, and a tab connecting portion 12. The terminal connecting portion 13 is connected to the current collecting body 11. The terminal connecting portion 13 includes a protrusion portion protruding in a thickness direction of the current collecting body 11, and a recess portion corresponding to a position of the protrusion portion. An end surface of the protrusion portion is used to connect the electrode terminal 3. A bottom surface of the recess portion has a roughness greater than a roughness of the current collecting body 11.

[0107] In these alternative embodiments, the extrusion process is combined with the extrusion process in the original current collecting member 1 manufacturing process, without adding other processes for manufacturing the current collecting member 1, and without affecting the normal process flow of the current collecting member 1 production.

[0108] According to an embodiment of the present application, the first extrusion and the second extrusion are performed synchronously.

[0109] In some embodiments, the first extrusion and the second extrusion use different embossing dies to form different embossed shapes on the sheet.

[0110] In these alternative embodiments, the manufacturing process of the current collecting member 1 is thus optimized.

[0111] Referring to FIG. 7, FIG. 7 is a structural schematic view of a terminal connecting portion of a current collecting member according to some embodiments of the present application.

[0112] According to an embodiment of the present application, the manufacturing method further includes: stamping the sheet to form a protruding protrusion portion and a recess portion corresponding to a position of the protrusion portion on the sheet. The step of extruding the sheet to increase the roughness of the surface of the pressed area of the sheet includes: extruding a bottom surface of the recess portion.

[0113] Exemplarily, as shown in FIG. 4 and FIG. 7, the sheet is provided; the sheet is stamped to form a protruding protrusion portion and a recess portion corresponding to a position of the protrusion portion on the sheet; the bottom surface of the recess portion is extruded for the first time to increase the roughness of the surface of the pressed area of the bottom surface, forming a first pressed area; the sheet is extruded for the second time to increase the roughness of the surface of the pressed area of the sheet, forming a second pressed area, wherein the first pressed area forms the terminal connecting portion 13 used to connect the electrode terminal 3, and the second pressed area forms the tab connecting portion 12 used to connect the tab 41.

[0114] In the embodiments of the present application, the sheet is punched to form a protruding convex portion and a concave portion corresponding to the position of the convex portion, the bottom surface of the concave portion is extruded, the sheet forms a first compression area, and the first compression area forms a terminal connecting portion 13 for connecting with the electrode terminal 3. Alternatively, the terminal is connected with the current collecting member 1 through laser welding, the laser welding hits the terminal connecting portion 13 and the terminal with a focused laser beam as a power source, so that the terminal connecting portion 13 and the terminal at the position hit by the laser are melted and re-solidified at the moment when the laser moves away, so that the terminal connecting portion 13 and the terminal are welded. During the welding process, the hitting of the laser causes the change of the density of the terminal connecting portion 13 and the terminal, thereby generating a height difference at the welding position. Therefore, the sheet forms a concave portion, and the bottom surface of the concave portion is extruded to form a rough surface.

[0115] Exemplarily, the embossing die for extruding the tab connecting portion 12 is directly installed on the punching equipment, and is combined with the punching process of the current collecting member 1, that is, on the punching equipment, the punching of the sheet, the first extrusion of the sheet, and the second extrusion of the sheet can be performed.

[0116] In these optional embodiments, the arrangement can reduce the risk of welding through of the current collecting member 1 and the electrode terminal 3, improve the welding success rate, and effectively improve the laser high reflection phenomenon during welding.

[0117] In some embodiments of the present application, the method for providing the current collecting member 1 in step S200 comprises: conveying the sheet to be punched to a processing line; processing positioning holes on the sheet; cutting the sheet to a predetermined contour; punching the sheet to form a protruding convex portion and a concave portion corresponding to the position of the convex portion; shaping the concave portion; first extruding the bottom surface of the concave portion, the sheet forms a first compression area, and the first compression area forms a terminal connecting portion 13 for connecting with the electrode terminal 3; second extruding the sheet, the sheet forms a second compression area, and the second compression area forms a tab connecting portion 12 for connecting with the tab 41.

[0118] According to one embodiment of the present application, the roughness Ra of the surface of the tab connecting portion 12 facing the tab 41 is 1 μm-5 μm.

[0119] In the embodiments of the present application, the roughness Ra of the surface of the tab connecting portion 12 facing the tab 41 is 1 μm-5 μm. The surface of the tab connecting portion 12 facing the tab 41 has a suitable roughness. In the process of welding the tab connecting portion 12 and the tab 41, a better welding effect can be achieved at a lower welding parameter process. The welding stability can be improved, and the welding cost can be reduced. When the roughness Ra is in the suitable range, the welding strength of the tab connecting portion 12 and the tab 41 can be improved with the increase of the roughness Ra. The probability of over-welding between the tab connecting portion 12 and the tab 41 caused by excessively high roughness Ra can be reduced.

[0120] Specifically, when the roughness Ra of the surface of the tab connecting portion 12 facing the tab 41 is 1 μm-5 μm, and the energy of the ultrasonic welding of the tab connecting portion 12 and the tab 41 is 260 J-380 J, the welding tension of the tab connecting portion 12 and the tab 41 can be improved, and the connection strength of the tab connecting portion 12 and the tab 41 can be improved.

[0121] In some embodiments of the present application, the roughness Ra of the surface of the tab connecting portion 12 facing the tab 41 is 1.0 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, 1.6 μm, 1.7 μm, 1.8 μm, 1.9 μm, 2.0 μm, 2.1 μm, 2.2 μm, 2.3 μm, 2.4 μm, 2.5 μm, 2.6 μm, 2.7 μm, 2.8 μm, 2.9 μm, 3.0 μm, 3.1 μm, 3.2 μm, 3.3 μm, 3.4 μm, 3.5 μm, 3.6 μm, 3.7 μm, 3.8 μm, 3.9 μm, 4.0 μm, 4.1 μm, 4.2 μm, 4.3 μm, 4.4 μm, 4.5 μm, 4.6 μm, 4.7 μm, 4.8 μm, 4.9 μm, 5 μm, or in other ranges consisting of any two endpoints of the above.

[0122] In these alternative embodiments, the surface of the tab connecting portion 12 facing the tab 41 has a suitable roughness Ra. The occurrence of over-welding between the tab connecting portion 12 and the tab 41 is reduced, and the connection strength of the electrode assembly 4 and the current collecting member 1 is further improved.

[0123] According to one embodiment of the present application, the energy of the ultrasonic welding is 260 J-380 J.

[0124] Specifically, the roughness Ra of the surface of the tab connecting portion 12 facing the tab 41 is 1 μm-5 μm, and the energy of the ultrasonic welding of the tab connecting portion 12 and the tab 41 is 260 J-380 J.

[0125] In some embodiments of the application, the ultrasonic welding energy is 260 J, 270 J, 280 J, 290 J, 310 J, 320 J, 330 J, 340 J, 350 J, 360 J, 370 J, 380 J, or in other ranges consisting of any two of the aforementioned endpoints.

[0126] In embodiments of the application, the roughness Ra of the surface of the tab connecting portion 12 facing the tab 41 is 1 μm-5 μm, which can achieve better welding effect at a lower welding energy during the welding process of the tab connecting portion 12 and the tab 41. In this welding process, the tensile strength of the electrode assembly 4 and the current collecting member 1 of the battery cell 10 obtained is 290 N-340 N, which is significantly higher than that of the battery cell 10 without roughening treatment of the tab connecting portion 12. In addition, the lower ultrasonic welding energy not only reduces the manufacturing cost, but also reduces the ultrasonic welding fluctuation, increases the ultrasonic welding stability, and improves the welding false welding problem caused by the ultrasonic welding fluctuation, thereby improving the reliability of the battery cell 10.

[0127] In these alternative embodiments, the lower ultrasonic welding energy can not only reduce the manufacturing cost of the battery cell 10, but also achieve high-strength connection of the electrode assembly 4 and the current collecting member 1.

[0128] According to an embodiment of the application, the amplitude of the ultrasonic welding is 25 μm-55 μm.

[0129] In some embodiments of the application, the amplitude of the ultrasonic welding is 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, 30 μm, 31 μm, 32 μm, 33 μm, 34 μm, 35 μm, 36 μm, 37 μm, 38 μm, 39 μm, 40 μm, 41 μm, 42 μm, 43 μm, 44 μm, 45 μm, 46 μm, 47 μm, 48 μm, 49 μm, 50 μm, 51 μm, 52 μm, 53 μm, 54 μm, 55 μm, or in other ranges consisting of any two of the aforementioned endpoints.

[0130] In these alternative embodiments, the ultrasonic welding has a suitable amplitude, the tab 41 and the surface of the tab connecting portion 12 rub against each other to form a molecular layer fusion, thereby improving the stability of the welding connection.

[0131] According to an embodiment of the application, the pressure of the ultrasonic welding is 25 Psi-45 Psi.

[0132] In some embodiments of the present application, the pressure of the ultrasonic welding is 25 Psi, 26 Psi, 27 Psi, 28 Psi, 29 Psi, 30 Psi, 31 Psi, 32 Psi, 33 Psi, 34 Psi, 35 Psi, 36 Psi, 37 Psi, 38 Psi, 39 Psi, 40 Psi, 41 Psi, 42 Psi, 43 Psi, 44 Psi, 45 Psi, or in other ranges consisting of any two endpoints of the above.

[0133] In these alternative embodiments, the ultrasonic welding reduces the gap between the tab 41 and the tab connecting portion 12 by applying appropriate pressure, thereby improving the welding strength of the tab 41 and the tab connecting portion 12.

[0134] According to one embodiment of the present application, the terminal connecting portion 13 and the electrode terminal 3 are laser welded.

[0135] In some embodiments, the electrode terminal 3 and the current collecting member 1 are connected by laser welding. However, when laser is irradiated onto the current collecting member 1, reflection occurs, and the smoother the surface being acted upon, the higher the reflectivity, i.e., laser high reflection occurs, thereby causing the energy of the laser not to be absorbed as much as possible into heat for welding, resulting in a decrease in the efficiency of laser welding and causing energy waste. Therefore, by roughening the surface of the current collecting member 1 for laser action, i.e., the surface of the terminal connecting portion 13 facing away from the electrode terminal 3, or machining a recess, the efficiency of laser welding is improved, thereby improving the welding stability between the electrode terminal 3 and the current collecting member 1.

[0136] In these alternative embodiments, the arrangement can improve the connection strength and stability between the electrode terminal 3 and the current collecting member 1.

[0137] In a second aspect, as shown in FIG. 3, the present application provides a battery monomer 10 comprising the battery monomer 10 manufactured according to the manufacturing method described above.

[0138] The battery monomer 10 provided by the present application is manufactured by the manufacturing method described above, the roughness of the surface of the tab connecting portion 12 facing the tab 41 is greater than the roughness of the surface of the current collecting body 11 facing the tab 41, and the tab connecting portion 12 is welded to the tab 41. By increasing the roughness of the surface of the tab connecting portion 12, better welding results can be achieved under lower welding parameters, which can improve the welding stability of the current collecting member 1 and the electrode assembly 4, and can also reduce the welding cost. At the same time, it can also reduce the problem of virtual welding and improve the reliability of the battery monomer 10.

[0139] According to an embodiment of the present application, the battery cell 10 comprises a housing 2, an electrode terminal 3, an electrode assembly 4, and a current collecting member 1; the electrode terminal 3 is disposed on the housing 2; the electrode assembly 4 is accommodated in the housing 2, and the electrode assembly 4 comprises a tab 41; the current collecting member 1 is used to connect the electrode terminal 3 and the tab 41, and the current collecting member 1 comprises a current collecting body 11 and a tab connecting portion 12, the tab connecting portion 12 is connected to the current collecting body 11, the tab connecting portion 12 is used to connect the tab 41, and the roughness of the surface of the tab connecting portion 12 facing the tab 41 is greater than the roughness of the surface of the current collecting body 11 facing the tab 41.

[0140] According to an embodiment of the present application, the current collecting member 1 further comprises a terminal connecting portion 13, the terminal connecting portion 13 is connected to the current collecting body 11, and the terminal connecting portion 13 is used to connect the electrode terminal 3.

[0141] In an embodiment of the present application, the terminal connecting portion 13 comprises a first surface and a second surface in the thickness direction, the first surface is a surface facing away from the electrode terminal 3, and the second surface is a surface facing the electrode terminal 3; before the current collecting member 1 is connected to the electrode terminal 3, the roughness of the first surface is greater than the roughness of the current collecting body 11.

[0142] In an embodiment of the present application, the structure of the terminal connecting portion 13 is different from that of the tab connecting portion 12.

[0143] In a third aspect, the present application provides a battery comprising the battery cell according to the foregoing.

[0144] In a fourth aspect, the present application provides an electric device comprising the battery according to the foregoing, and the battery is used to provide electric energy.

[0145] Embodiment 1

[0146] The battery cell comprises a housing, an electrode terminal, an electrode assembly, and a current collecting member; the electrode terminal is disposed on the housing; the electrode assembly is accommodated in the housing, and the electrode assembly comprises a tab; the current collecting member is connected to the electrode terminal, and comprises a current collecting body, a tab connecting portion, and a terminal connecting portion; the tab connecting portion is connected to the current collecting body, the tab connecting portion is ultrasonic welded with the tab, the terminal connecting portion is connected to the current collecting body, and the terminal connecting portion is laser welded with the electrode terminal.

[0147] The method for manufacturing the battery cell comprises:

[0148] In step S100, an electrode assembly is provided, and the electrode assembly comprises a tab;

[0149] Step S200, providing a sheet; stamping the sheet to form a protruding protrusion and a recess corresponding to the position of the protrusion on the sheet; first embossing the bottom surface of the recess to form a first pressure area, the first pressure area forming a terminal connecting part; second embossing the sheet to form a second pressure area, the second pressure area forming a tab connecting part, the roughness of the surface of the tab connecting part facing the surface of the tab being 3 μm; ultrasonic welding the tab connecting part and the tab, the energy of the ultrasonic welding being 260 J, the amplitude being 35 μm, and the pressure being 34 Psi.

[0150] Step S300, providing a shell and an electrode terminal arranged on the shell, laser welding the terminal connecting part and the electrode terminal, and installing the electrode assembly into the shell.

[0151] The battery cells of Examples 1-11 and Comparative Examples 1-9 were manufactured according to Table 1 below, and the tensile force of the battery cells of each example and comparative example was tested, with the sample size of each group being 15.

[0152] Table 1 Manufacturing process parameters and test results of the battery cells of Examples 1-11 and Comparative Examples 1-9.

[0153] As can be seen from Table 1 and FIG. 8, in which the test results of the battery cells of Examples 1 to 7 and Comparative Examples 1 to 7 are shown, 260 represents the battery cells manufactured under the conditions of an ultrasonic welding energy of 260 J, an amplitude of 35 μm, and a pressure of 34 Psi, 1 represents the battery cells manufactured without roughening, 2 represents the battery cells manufactured with a roughness of 3 μm at the tab connecting portion, and so on. As can be seen from the overall comparison of the examples and the comparative examples, by roughening the tab connecting portion, the electrode assembly and the current collecting member connected by ultrasonic welding are improved, the welding tension is increased, and the tension fluctuation is reduced. As the ultrasonic welding energy is continuously increased, the roughness gradually reduces the improvement of the welding effect. At 380 J, the roughness tension value is similar to the smooth surface tension value, which is probably because, as the ultrasonic welding energy is increased, the influence of the roughness is gradually reduced, and overwelding may occur when the energy exceeds 380 J. Ultrasonic welding generates heat by high-speed friction to achieve the connection of the tab and the current collecting member. The increase of the roughness of the tab connecting portion generates more heat at the contact surface of the tab and the current collecting member, thereby facilitating the connection of the tab and the current collecting member. However, as the energy is continuously increased, when the energy value exceeds 380 J, overwelding occurs due to the roughening, resulting in a reduction of the tension value. When the roughness Ra is in an appropriate range, the welding strength of the tab connecting portion and the tab is increased with the increase of the roughness Ra, but excessively high roughness Ra may cause overwelding of the tab connecting portion and the tab, resulting in a reduction of the tension value. Therefore, the introduction of the roughness of the current collecting member is helpful to the improvement of the ultrasonic welding tension and has a positive effect on the stability of the tension value. The introduction of the roughness can appropriately reduce the original ultrasonic welding process parameters, and the purpose of equivalent or even better welding effect can be achieved, that is, the corresponding welding strength can be achieved by using low ultrasonic welding process, and the occurrence of false welding is reduced.

[0154] Although the present application has been described with reference to the preferred embodiments, various modifications can be made to it without departing from the scope of the application, and equivalent substitutions can be made to the components thereof, and in particular, the technical features mentioned in each embodiment can be combined in any manner as long as there is no structural conflict. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for manufacturing a battery cell, comprising: Providing an electrode assembly, the electrode assembly including a tab; A current collecting component is provided, the current collecting component including a tab connecting portion and a current collecting body, the tab connecting portion is ultrasonically welded to the tab, Wherein, providing the current collecting member includes: providing a sheet material, pressing the sheet material to increase the surface roughness of a pressed area of ​​the sheet material, wherein the pressed area forms at least a tab connecting portion for connecting to the tab, and the roughness of a surface of the tab connecting portion facing the tab is greater than the roughness of a surface of the current collecting body facing the tab; A housing and an electrode terminal disposed on the housing are provided, the current collecting member is connected to the electrode terminal, and the electrode assembly is installed in the housing.

2. The manufacturing method according to claim 1, wherein The step of pressing the sheet material to increase the surface roughness of the pressed area of ​​the sheet material comprises: performing a first compression on the sheet to form a first compressed area on the sheet; The sheet is subjected to a second extrusion, and a second compressed area is formed on the sheet. One of the first pressure-bearing region and the second pressure-bearing region forms a terminal connection portion for connecting to the electrode terminal, and the other forms the tab connection portion for connecting to the tab.

3. The manufacturing method according to claim 2, wherein: The first extrusion and the second extrusion are performed simultaneously.

4. The manufacturing method according to claim 2, wherein: The roughness of at least a portion of a surface of the terminal connection portion facing away from the electrode terminal is greater than the roughness of the current collecting body.

5. The manufacturing method according to claim 2, wherein: The manufacturing method further comprises: punching the sheet material to form a protruding convex portion and a concave portion corresponding to the position of the protruding portion on the sheet material; The step of pressing the sheet material to increase the roughness of the surface of the pressed area of ​​the sheet material includes pressing the bottom surface of the concave portion.

6. The manufacturing method according to claim 1, wherein The roughness Ra of the surface of the tab connecting portion facing the tab is 1 μm-5 μm.

7. The manufacturing method according to claim 1, wherein: The energy of the ultrasonic welding is 260J-380J.

8. The manufacturing method according to claim 1, wherein: The amplitude of the ultrasonic welding is 25 μm-55 μm; and / or, The ultrasonic welding pressure is 25Psi-45Psi.

9. The manufacturing method according to claim 2, wherein: The terminal connection portion and the electrode terminal are welded by laser.

10. A battery cell manufactured by the manufacturing method according to any one of claims 1 to 9.

11. The battery cell according to claim 10, wherein: include: the housing; The electrode terminal is provided on the housing; The electrode assembly is accommodated in the housing, and the electrode assembly includes the tab; as well as The current collecting member is used to connect the electrode terminal and the tab. The current collecting member includes the current collecting body and the tab connecting portion. The tab connecting portion is connected to the current collecting body and is used to connect the tab.

12. The battery cell according to claim 10 or 11, wherein: The current collecting member further includes a terminal connection portion connected to the current collecting body, the terminal connection portion being used to connect to the electrode terminal. 13 . A battery comprising the battery cell according to claim 10 .

14. An electrical device comprising the battery according to claim 13, wherein the battery is used to provide electrical energy.

Images