Electrode sheet manufacturing method

Abstract

Disclosed in the present application is an electrode sheet manufacturing method. The method comprises the following steps: providing a substrate, wherein the substrate comprises a substrate body and a protective layer, and in the direction of thickness of the substrate, the protective layer is arranged on the surface of the substrate body; and slitting the substrate, wherein the substrate body is slit into at least one electrode sheet body, and the protective layer is slit into a protective member covering the entire slit section of the at least one electrode sheet body. The technical solution provided in the present application can effectively improve the reliability of a battery.

Description

Method for manufacturing pole piece

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese Patent Application No. 202410431541.3, filed on April 11, 2024, entitled “Method for Manufacturing Pole Piece”, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0003] The present application relates to the technical field of batteries, in particular to a method for manufacturing a pole piece. BACKGROUND

[0004] Energy saving and emission reduction is the key to the sustainable development of the automobile industry. Electric vehicles have become an important part of the sustainable development of the automobile industry due to their energy-saving and environmentally friendly advantages. For electric vehicles, battery technology is an important factor for their development.

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

[0006] SUMMARY

[0007] The present application provides a method for manufacturing a pole piece, which can effectively improve the reliability of the battery.

[0008] The present application provides a method for manufacturing a pole piece, which includes the following steps:

[0009] Providing a substrate, the substrate includes a substrate body and a protective layer, along the thickness direction of the substrate, the protective layer is arranged on the surface of the substrate body;

[0010] Slitting the substrate, the substrate body is slitted into at least one pole piece body, and the protective layer is slitted into a protective member covering the entire slitting surface of the at least one pole piece body.

[0011] The technical scheme provided by some embodiments of the present application can form a protective member covering the entire slitting surface of the substrate body by arranging the protective layer on the substrate body before slitting the pole piece substrate and corresponding to the slitting position, so as to cover the burrs and metal particles generated by slitting the substrate body, thereby avoiding the exposure of the pole piece edge burrs and metal particles, effectively reducing the risk of burrs and metal particles piercing the separator, causing internal short circuit of the battery monomer, making the battery monomer have higher reliability, and further making the battery have higher reliability.

[0012] According to some embodiments of the present application, the protective layer includes a polymer layer.

[0013] In the above scheme, the protective layer is provided to include a polymer layer, and the physical properties of the polymer can be used to cover the slitting surface of the pole piece body by extrusion or heating to make the polymer layer melt and flow, etc., so as to form a protective member capable of covering burrs and metal particles, effectively reducing the risk of burrs and metal particles piercing the separator and causing internal short circuit of the battery cell, so that the battery cell has higher reliability, and the battery has higher reliability.

[0014] According to some embodiments of the present application, the material of the polymer layer includes at least one of polyethylene terephthalate, polytetrafluoroethylene, polyvinylidene fluoride, polypropylene, polyethylene, polyvinyl chloride, polycarbonate, polyimide, or polyamide-imide.

[0015] According to some embodiments of the present application, the substrate is provided by hot pressing the protective layer on the surface of the substrate body.

[0016] In the above scheme, the protective layer includes a polymer layer, which can be efficiently arranged on the surface of the substrate body by heating and rolling, and has a stable connection relationship with the substrate body, which is conducive to forming a protective member covering the cutting surface of the pole piece body during slitting, thereby covering burrs and metal particles, effectively reducing the risk of burrs and metal particles piercing the separator and causing internal short circuit of the battery cell, so that the battery cell has higher reliability, and the battery has higher reliability.

[0017] According to some embodiments of the present application, the protective layer further includes an adhesive layer, which is stacked with the polymer layer along the thickness direction of the substrate. The substrate is provided by adhering the polymer layer to the surface of the substrate body through the adhesive layer.

[0018] In the above scheme, the polymer layer can be efficiently adhered to the surface of the substrate body through the adhesive layer, so that the polymer layer and the substrate body have a stable connection relationship, which is conducive to forming a protective member covering the cutting surface of the pole piece body during slitting, thereby covering burrs and metal particles, effectively reducing the risk of burrs and metal particles piercing the separator and causing internal short circuit of the battery cell, so that the battery cell has higher reliability, and the battery has higher reliability.

[0019] According to some embodiments of the present application, the substrate body includes a current collector and an active material layer, and the active material layer is arranged on the surface of the current collector along the thickness direction of the substrate body, and the protective layer is arranged on the surface of the active material layer away from the current collector.

[0020] In the above scheme, after the coating process, a protective layer is arranged on the surface of the active material layer, so that the protective layer is cut to form a protective piece capable of covering the cut surface of the substrate body, and burrs and metal particles generated by cutting of the current collector are covered, thereby avoiding exposure of the tab edge burrs and metal particles, effectively reducing the risk of burrs and metal particles piercing the separator and causing internal short circuit of the battery cell, so that the battery cell has high reliability, and the battery has high reliability.

[0021] According to some embodiments of the present application, the cutting of the substrate includes: cutting the substrate body into two tab bodies side by side along a first direction, and cutting the protective layer into two protective pieces respectively covering the cut surfaces of the two tab bodies, the first direction being perpendicular to the thickness direction of the substrate.

[0022] In the above scheme, the substrate body is cut into two tab bodies side by side along the position where the protective layer is located, and the protective layer is cut into two protective pieces respectively covering the cut surfaces of the corresponding tab bodies to form protective pieces respectively, thereby efficiently cutting the tab, and facilitating the improvement of battery manufacturing efficiency.

[0023] According to some embodiments of the present application, the cutting of the substrate further includes: cutting the substrate along the center line of the protective layer.

[0024] In the above scheme, the center line of the protective layer can be a cutting line of the substrate, and the substrate is cut along the center line of the protective layer, so that the protective layer is cut into two protective pieces of equal size, effectively covering the cut surfaces of the respective corresponding tab bodies, thereby effectively reducing the risk of burrs and metal particles piercing the separator and causing internal short circuit of the battery cell, so that the battery cell has high reliability, and the battery has high reliability.

[0025] According to some embodiments of the present application, along the thickness direction of the substrate, the size of the substrate body is M, and along the first direction, the size of the protective layer is L, satisfying 2*M≤L≤2*M+0.5mm.

[0026] In the above scheme, the size of the protective layer in the first direction is set to be not less than twice the thickness of the substrate body, so that the protective piece formed by cutting of the protective layer can effectively cover the cut surface of the tab body, reduce the risk of burrs and metal particles piercing the separator and causing short circuit of the battery cell, and make the battery have high reliability. The size of the protective layer in the first direction is set to be not more than twice the thickness of the substrate body plus 0.5mm, which can reduce the influence of the protective piece on the active material of the tab or the influence on the conductivity, and reduce the influence on the charge-discharge performance or energy density of the battery. Therefore, by setting the size of the protective layer in the first direction to be not less than twice the thickness of the substrate body and not more than twice the thickness of the substrate body plus 0.5mm, the reliability, charge-discharge performance or energy density of the battery can be considered.

[0027] According to some embodiments of the present application, the size of the substrate body in the thickness direction of the substrate is M, and the size of the protective layer in the first direction is L, satisfying 2*M≤L≤2*M+0.1mm.

[0028] In the above scheme, the size of the protective layer in the first direction is set to be not less than twice the thickness of the substrate body, so that the protective member formed by slitting the protective layer can effectively cover the slitting section of the pole piece body, reducing the risk of the burrs and metal particles piercing the separator leading to internal short circuit of the battery cell, so that the battery has higher reliability. The size of the protective layer in the first direction is set to be not more than twice the thickness of the substrate body plus 0.1mm, which can effectively reduce the influence of the protective member on the active material of the pole piece or the influence on the conductivity, effectively reducing the influence on the charge-discharge performance or energy density of the battery. Therefore, by setting the size of the protective layer in the first direction to be not less than twice the thickness of the substrate body and not more than twice the thickness of the substrate body plus 0.1mm, the reliability, charge-discharge performance or energy density of the battery can be effectively balanced.

[0029] According to some embodiments of the present application, the slitting the substrate comprises:

[0030] The protective layer covers the entire slitting section of the pole piece body under the extrusion of the cutter to form the protective member.

[0031] In the above scheme, the substrate is slit by the cutter, so that the protective layer deforms along the slitting section of the pole piece body under the extrusion force of the cutter, and is pasted and covered on the slitting section of the pole piece body, thereby covering the burrs and metal particles on the slitting section, reducing the risk of the burrs and metal particles piercing the separator leading to internal short circuit of the battery cell, so that the battery cell has higher reliability, and the battery has higher reliability.

[0032] According to some embodiments of the present application, the slitting the substrate further comprises:

[0033] The cutter is heated, and the substrate is slit by the heated cutter. The protective layer melts and covers the entire slitting section of the pole piece body under the heating and extrusion of the cutter to form the protective member.

[0034] In the above scheme, the substrate is slit by the heated cutter, so that the protective layer not only receives the extrusion force, but also is in a molten state due to heating, so as to effectively cover and stably paste on the slitting section of the pole piece body, thereby effectively covering the burrs and metal particles on the slitting section, effectively reducing the risk of the burrs and metal particles piercing the separator leading to internal short circuit of the battery cell, so that the battery cell has higher reliability, and the battery has higher reliability.

[0035] According to some embodiments of the present application, the heating temperature of the cutting knife is not less than 100 degrees Celsius and not greater than 350 degrees Celsius.

[0036] In the above scheme, by setting the temperature of the cutting knife to be not less than 100 degrees Celsius, the protective layer can be effectively heated to melt and improve the effect of covering the slitting surface, thereby improving the reliability of the battery; by setting the temperature of the cutting knife to be not greater than 100 degrees Celsius, the risk of the protective layer vaporizing due to overheating can be effectively reduced, so that the protective layer melts to improve the effect of covering the slitting surface, thereby improving the reliability of the battery. Therefore, by setting the temperature of the cutting knife to be not less than 100 degrees Celsius and not greater than 100 degrees Celsius, the risk of burrs and metal particles piercing the separator to cause internal short circuit of the battery cell can be effectively reduced, so that the battery cell has higher reliability, and the battery has higher reliability.

[0037] According to some embodiments of the present application, after the substrate is slitted, the method further comprises the step of heating the protective member to melt the protective member.

[0038] In the above scheme, by heating the protective member, the protective member can be melted and flowed to make the thickness of the protective member uniform, further improving the covering effect of the slitting surface of the pole piece body, thereby effectively reducing the risk of burrs and metal particles piercing the separator to cause internal short circuit of the battery cell, so that the battery cell has higher reliability, and the battery has higher reliability.

[0039] According to some embodiments of the present application, the slitting substrate further comprises:

[0040] By laser slitting the substrate, the protective layer melts and covers the entire slitting surface of the pole piece body under the action of the laser to form a protective member.

[0041] In the above scheme, by laser slitting the substrate, on the one hand, the substrate body and the protective layer can be accurately slitted to improve the accuracy of the pole piece size; on the other hand, the protective layer can be melted due to the high temperature generated by the laser during slitting to be pasted and covered on the slitting surface of the pole piece body, thereby covering the burrs and metal particles of the slitting surface, reducing the risk of burrs and metal particles piercing the separator to cause internal short circuit of the battery cell, so that the battery cell has higher reliability, and the battery has higher reliability.

[0042] According to some embodiments of the present application, the protective layer is located above the substrate body in the direction of gravity.

[0043] In the above scheme, by arranging the protective layer above the substrate body, the protective layer in a molten state can effectively flow along the slitting section under the action of gravity, thereby effectively covering the slitting section, covering the burrs and metal particles of the slitting section, reducing the risk of burrs and metal particles piercing the separator, causing internal short circuit of the battery monomer, so that the battery monomer has higher reliability, and thus the battery has higher reliability.

[0044] The above description is only a summary of the technical solutions of the embodiments of the present application. In order to enable the technical means of the present application to be more clearly understood, the embodiments of the present application can be implemented according to the content of the description, and in order to enable the above and other purposes, features and advantages of the present application to be more obvious and easy to understand, the following specific embodiments of the present application are described. BRIEF DESCRIPTION OF DRAWINGS

[0045] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0046] Fig. 1 is a schematic view of a vehicle in some embodiments of the present application;

[0047] Fig. 2 is a perspective exploded view of a battery provided in some embodiments of the present application;

[0048] Fig. 3 is a perspective exploded view of a battery monomer provided in some embodiments of the present application;

[0049] Fig. 4 is a schematic view of a pole piece in some embodiments of the present application;

[0050] Fig. 5 is a flow chart of a manufacturing method of a pole piece in some embodiments of the present application;

[0051] Fig. 6 is a top view of a substrate in some embodiments of the present application;

[0052] Fig. 7 is a side view of a substrate in some embodiments of the present application;

[0053] Figs. 8-11 are schematic views of the manufacturing process of a pole piece in some embodiments of the present application;

[0054] Fig. 12 is a schematic view of a protective layer in some other embodiments of the present application;

[0055] Figs. 13-15 are schematic views of the manufacturing process of a pole piece in some other embodiments of the present application.

[0056] Icon: 500 - substrate; 50 - substrate body; 51 - current collector; 510 - empty foil area; 52 - active material layer; 60 - protective layer; 61 - polymer layer; 62 - adhesive layer; 403 - slitting line; 40 - tab; 41 - tab body; 410 - slitting section; 42 - protector; 70 - cutter; 80 - laser device; x - first direction; y - second direction; z - thickness direction of the substrate; 1000 - vehicle; 100 - battery; 200 - controller; 300 - motor; 30 - case; 31 - upper case; 32 - lower case; 10 - battery cell; 11 - electrode assembly; 111 - tab; 12 - housing; 120 - casing; 121 - end cover; 13 - electrode terminal; 14 - adapter. DETAILED DESCRIPTION

[0057] 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 those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0058] 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 specification of the present application are only for the purpose of describing specific embodiments 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, not to describe a particular order or primary and secondary relationship.

[0059] 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 refer to the same embodiment, nor is it an independent or alternative embodiment to other embodiments.

[0060] 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, it can be fixed connection, or detachable connection, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium; it can be the communication inside two elements. For those 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.

[0061] The term "and / or" in the present application is only used to describe the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B can represent 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.

[0062] 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.

[0063] "Multiple" appearing in the present application means two or more (including two).

[0064] In the present application, the battery cell can include 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 present application embodiments are not limited thereto. The battery cell can be in the shape of a cylinder, a flat body, a cuboid, or other shapes, etc. The present application embodiments are also not limited thereto.

[0065] The battery referred to 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. The battery generally includes a box for packaging one or more battery cells. The box can avoid the influence of liquid or other foreign matters on the charging or discharging of the battery cell.

[0066] A battery cell includes an electrode assembly and an electrolyte, and the electrode assembly is composed of a positive electrode tab, a negative electrode tab, and a separator. The battery cell mainly relies on the movement of metal ions between the positive electrode tab and the negative electrode tab to work. The positive electrode tab includes a positive electrode current collector and a positive electrode active material layer, and the positive electrode active material layer is coated on the surface of the positive electrode current collector. The positive electrode current collector without the positive electrode active material layer protrudes from the positive electrode current collector with the positive electrode active material layer, and the positive electrode current collector without the positive electrode active material layer serves as a positive electrode tab. Taking a lithium ion battery as an example, the material of the positive electrode current collector can be aluminum, and the positive electrode active material can be lithium cobaltate, lithium iron phosphate, ternary lithium, or lithium manganate, etc. The negative electrode tab includes a negative electrode current collector and a negative electrode active material layer, and the negative electrode active material layer is coated on the surface of the negative electrode current collector. The negative electrode current collector without the negative electrode active material layer protrudes from the negative electrode current collector with the negative electrode active material layer, and the negative electrode current collector without the negative electrode active material layer serves as a negative electrode tab. The material of the negative electrode current collector can be copper, and the negative electrode active material can be carbon or silicon, etc. The material of the separator can be PP (polypropylene) or PE (polyethylene), etc. In addition, the electrode assembly can be a winding type structure or a stacking type structure, and the embodiments of the present application are not limited thereto.

[0067] The development of battery technology needs to consider various design factors, such as battery life, energy density, discharge capacity, charge-discharge rate, and other performance parameters. In addition, the reliability of the battery also needs to be considered. In the manufacturing process of the battery, the size of the battery cell is produced according to the needs, and the electrode tab material belt is slitting to obtain multiple electrode tabs with sizes meeting the needs. However, the current collector is generally made of metal material, such as aluminum or copper. The burrs and metal particles generated by the metal current collector during the electrode tab slitting process may pierce the separator, causing the positive and negative electrodes of the battery cell to be short-circuited, resulting in high voltage breakdown and even thermal runaway risk, affecting the reliability of the battery.

[0068] In view of this, in order to improve the problem of low battery reliability caused by burrs and metal particles generated during the slitting of the electrode tab, some embodiments of the present application provide a manufacturing method of an electrode tab, the electrode tab includes an electrode tab body and a protective piece, the protective piece covers the entire slitting section of the electrode tab body, and the method includes the following steps:

[0069] A substrate is provided, the substrate includes a substrate body and a protective layer, and the protective layer is arranged on the surface of the substrate body in the thickness direction of the substrate;

[0070] The substrate is slitting, the substrate body is slitting into at least one electrode tab body, and the protective layer is slitting to form a protective piece covering the entire slitting section of the at least one electrode tab body, thereby obtaining at least one electrode tab.

[0071] Before slitting the jelly-roll substrate, by setting the protective layer on the substrate body, the protective layer can be formed as a protective piece covering the slitting surface of the substrate body during the slitting process, and the burrs and metal particles generated by the slitting of the substrate body are covered, thereby avoiding the exposure of the jelly-roll edge burrs and metal particles, effectively reducing the risk of burrs and metal particles piercing the separator, causing internal short circuit of the battery cell, making the battery cell have higher reliability, and thus making the battery have higher reliability.

[0072] The technical solutions described in the embodiments of the present application are suitable for manufacturing jelly-rolls for battery cells, batteries and electric devices using batteries.

[0073] The electric device can be a vehicle, a mobile phone, a portable device, a notebook computer, a ship, a spacecraft, an electric toy and an electric tool, 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 car toy, an electric ship toy and an electric plane 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, a power drill, a power grinder, a power wrench, a power screwdriver, an electric hammer, an impact drill, a concrete vibrator and an electric planer, etc. The embodiments of the present application do not specially limit the above-mentioned electric devices.

[0074] The following embodiments take the vehicle as an example for convenience of description.

[0075] Please refer to FIG. 1, which is a schematic diagram of a vehicle in some embodiments of the present application. The vehicle 1000 can be a fuel car, a gas car or a new energy car, and the new energy car can be a pure electric car, a hybrid car or a range extended car, etc. The vehicle 1000 is internally provided with a battery 100, which can be arranged at the bottom, head or tail of the vehicle 1000. The battery 100 can be used for power supply of the vehicle 1000, for example, the battery 100 can be used as the operating power supply of the vehicle 1000. The vehicle 1000 can further include a controller 200 and a motor 300, and the controller 200 is used to control the battery 100 to supply power to the motor 300, for example, for the working power demand of the vehicle 1000 during starting, navigation and driving.

[0076] In some embodiments of the present application, the battery 100 can not only be used as the operating power supply of the vehicle 1000, but also be used as the driving power supply of the vehicle 1000, instead of or partially instead of fuel or natural gas to provide driving power for the vehicle 1000.

[0077] Please refer to FIG. 2, which is a perspective exploded view of the battery 100 according to some embodiments of the present application. The battery 100 includes a box 30 and a battery cell 10, which is accommodated in the box 30. The box 30 is configured to provide a space for accommodating the battery cell 10, and can have various structures. In some embodiments, the box 30 can include an upper box 31 and a lower box 32, which are coupled to each other to define a space for accommodating the battery cell 10. The lower box 32 can have a hollow structure with one open end, and the upper box 31 can have a plate structure. The upper box 31 is coupled to the open end of the lower box 32 to define the space for accommodating the battery cell 10. Alternatively, the upper box 31 and the lower box 32 can each have a hollow structure with one open end, and the open end of the upper box 31 is coupled to the open end of the lower box 32. Of course, the box 30 formed by the upper box 31 and the lower box 32 can have various shapes, such as a cylindrical shape or a cuboid shape.

[0078] In the battery 100, the battery cell 10 can be a plurality of battery cells 10, which can be connected in series, in parallel, or in a mixed manner. The mixed manner means that the plurality of battery cells 10 are connected in series and in parallel. The plurality of battery cells 10 can be directly connected in series, in parallel, or in a mixed manner, and the plurality of battery cells 10 are accommodated in the box 30. Alternatively, the plurality of battery cells 10 can be connected in series, in parallel, or in a mixed manner to form a battery module, and a plurality of battery modules are connected in series, in parallel, or in a mixed manner to form a whole, which is accommodated in the box 30. The battery 100 can further include other structures, for example, the battery 100 can further include a busbar component for electrically connecting the plurality of battery cells 10.

[0079] Each battery cell 10 can be a secondary battery cell or a primary battery cell, and can be a lithium-sulfur battery cell, a sodium-ion battery cell, or a magnesium-ion battery cell, but is not limited thereto. The battery cell 10 can have a cylindrical shape, a flat shape, a cuboid shape, or other shapes.

[0080] Please refer to FIG. 3, which is a perspective exploded view of the battery cell 10 according to some embodiments of the present application. The battery cell 10 includes an electrode assembly 11 and a case 12. The case 12 includes a case body 120 and a terminal cap 121. The case body 120 has an opening, and the electrode assembly 11 is disposed in the case body 120. The terminal cap 121 is coupled to the case body 120 to close the opening, so that the electrode assembly 11 is located in a closed space. In some embodiments, the terminal cap 121 can be provided with a liquid injection hole, and electrolyte can be injected into the case through the liquid injection hole. In some embodiments, the terminal cap 121 can be riveted, welded, adhered, or threadedly coupled to the case body 120.

[0081] In some embodiments, the shell 12 is determined according to the shape of the one or more electrode assemblies 11 combined (i.e. in some embodiments of the present application, the number of electrode assemblies in a battery cell can be one or more), for example, the shell 12 can be a hollow cuboid or a hollow cube or a hollow cylinder. In some embodiments of the present application, the shell 12 can be made of a metal material, for example, aluminum or aluminum alloy, etc. The shell 12 can also be made of plastic. In some embodiments, the shell 12 is provided with electrode terminals 13, which are connected with the tabs 111 of the electrode assemblies 11 to realize the output and input of electric energy. In some embodiments of the present application, the positions of the electrode terminals 13 are not limited, for example, the electrode terminals 13 with opposite polarities are arranged on the same wall of the shell to connect the tabs 111 with the respective corresponding polarity, for example, the electrode terminals 13 with opposite polarities are arranged on the end cover 121; for another example, the electrode terminals 13 with opposite polarities are arranged on different walls of the shell to connect the tabs 111 with the respective corresponding polarity, for example, the electrode terminals 13 with one polarity are arranged on the end cover 121, and the electrode terminals 13 with the other polarity are arranged on the bottom wall of the shell 120. In some embodiments, the electrode terminals 13 are connected with the tabs 111 through adapters 14.

[0082] The electrode assembly 11 is composed of a pole piece and a separator, the pole piece includes a positive pole piece and a negative pole piece with opposite polarities, and the separator is arranged between the positive pole piece and the negative pole piece. For example, the positive pole piece includes a positive current collector and a positive active material layer, the positive active material layer is coated on the surface of the positive current collector, the positive current collector without the positive active material layer is protruded from the positive current collector with the positive active material layer, the positive current collector without the positive active material layer serves as a positive tab, and the positive pole piece is connected with a corresponding electrode terminal. In some embodiments, the material of the positive current collector can include aluminum or other metals. The negative pole piece includes a negative current collector and a negative active material layer, the negative active material layer is coated on the surface of the negative current collector, the negative current collector without the negative active material layer is protruded from the negative current collector with the negative active material layer, the negative current collector without the negative active material layer serves as a negative tab, and the negative tab is connected with a corresponding electrode terminal. In some embodiments, the material of the negative current collector can include copper or other metals.

[0083] In some embodiments of the present application, a manufacturing method of a pole piece is provided, which can be a positive pole piece or a negative pole piece. Please refer to FIG. 4 to FIG. 11, FIG. 4 is a schematic diagram of a pole piece in some embodiments of the present application, FIG. 5 is a flow chart of a manufacturing method of a pole piece in some embodiments of the present application, FIG. 6 is a top view of a substrate in some embodiments of the present application, FIG. 7 is a side view of the substrate in some embodiments of the present application, and FIG. 8 to FIG. 11 are schematic diagrams of the manufacturing process of the pole piece in some embodiments of the present application.

[0084] The manufacturing method of the pole piece can include the following steps:

[0085] S1, providing a substrate 500, the substrate 500 comprising a substrate body 50 and a protective layer 60, the protective layer 60 being disposed on a surface of the substrate body 50 along a thickness direction z of the substrate;

[0086] S2, slitting the substrate 500 to divide the substrate body 50 into at least one pole piece body 41, and to divide the protective layer 60 into a protective member 42 covering an entire slitting surface 410 of the at least one pole piece body 41.

[0087] In some embodiments, after performing step S2, the substrate 500 is slit, at least one pole piece 40 can be obtained.

[0088] In some embodiments, the pole piece 40 obtained by the above steps comprises the pole piece body 41 and the protective member 42, the protective member 42 covering the slitting surface 410 of the pole piece body 41. In some embodiments, the pole piece body 41 comprises a current collector 51 and an active material layer 52, the active material layer 52 being disposed on a surface of the current collector 51 along a thickness direction of the substrate body 50. In some embodiments, the current collector 51 can comprise a metal current collector 51, for example, the current collector 51 is a metal foil. In other embodiments, the current collector 51 can be a composite current collector 51, the composite current collector 51 comprising a metal foil and an intermediate layer, the intermediate layer being sandwiched between two metal foils, the material of the intermediate layer can be a polymer. The pole piece body 41 before slitting is the substrate body 50, the substrate body 50 is slit into pole piece bodies 41 of required size by the action of the cutter 70 or the laser during the slitting process. The slitting surface 410 of the pole piece body 41 can be understood as the surface formed by the action of the cutter 70 or the laser on the substrate body 50 during the slitting process. For example, when the substrate body 50 is slit into two pole piece bodies 41 by the action of the cutter 70 or the laser, the surfaces of the two pole piece bodies 41 facing each other are the respective slitting surfaces 410.

[0089] The "protective member 42 covering the entire slitting surface 410 of the pole piece body 41" can be understood as the entire slitting surface 410 of the pole piece body 41 being covered by the protective member 42, so as to encapsulate the burrs and metal particles generated on the slitting surface 410 of the pole piece body 41 due to slitting, so that the burrs and metal particles are isolated from the outside. In some embodiments, the protective member 42 can cover the slitting surface 410 of the pole piece body 41 entirely. In some embodiments, part of the protective member 42 can cover the slitting surface 410 of the pole piece body 41, and another part can be disposed on a surface of the pole piece body 41 adjacent to the slitting surface 410.

[0090] In some embodiments, in the step S1, providing the substrate 500, the substrate body 50 can be a large-size current collector 51 and an active material layer 52 disposed on the large-size current collector 51. The protective layer 60 can be in a state before the cutting of the protective member 42, that is, it can be understood that the protective layer 60 is cut to form the protective member 42 covering the cutting surface 410.

[0091] In the step S1, providing the substrate 500, the protective layer 60 can be disposed corresponding to the cutting line 403 of the substrate 500. The "cutting line 403 of the substrate 500" can be understood as, in the cutting, the cutting knife 70 or the laser is aligned with the cutting line 403 to cut the substrate 500, so as to cut the substrate 500 into the pole piece 40 meeting the size requirement. Exemplarily, taking the width direction of the substrate 500 as the first direction x, the length direction of the substrate 500 as the second direction y, and the thickness direction of the substrate as the third direction z, the cutting line 403 can be parallel to the second direction y, and the cutting line 403 can be the center line of the substrate 500 parallel to the second direction y. Cutting the substrate 500 along the cutting line 403 can cut the substrate 500 into two pole pieces 40 of the same size.

[0092] The "protective layer 60 is disposed corresponding to the cutting line 403 of the substrate 500" can be understood as the protective member 42 can cover the cutting line 403 of the substrate 500, so that in the cutting of the substrate 500, the cutting knife 70 or the laser can act on the protective layer 60, and the protective layer 60 can form the protective member 42 in the process of cutting.

[0093] In some embodiments, in the step S2, cutting the substrate 500, "cutting the substrate body 50 into at least one pole piece body 41" can be understood as cutting the substrate 500 along the cutting line 403, and the number of the pole pieces 40 obtained can be one, two or more. Exemplarily, the substrate 500 is provided with one cutting line 403, and the substrate 500 can be cut into one pole piece 40 or two pole pieces 40 along the one cutting line 403. When cut into one pole piece 40, the remaining substrate 500 can be regarded as waste, and when cut into two pole pieces 40, the part of the substrate 500 on both sides of the cutting line 403 can be regarded as the pole pieces 40. In some embodiments, the substrate 500 is provided with two or more cutting lines 403, and the substrate 500 is cut along the two or more cutting lines 403, so as to obtain two, three or more pole pieces 40. For example, the substrate 500 has a plurality of protective layers 60 arranged at intervals in the first direction x, and each protective layer 60 is disposed corresponding to a cutting line 403. By cutting the substrate 500 corresponding to each protective layer 60, a plurality of pole pieces 40 can be obtained.

[0094] The "protective layer 60 is slit to form the protective member 42 covering the entire slit surface 410 of the at least one pole piece body 41" can be understood as that, in the process of slitting, the protective layer 60 is slit and changes in form under the influence of slitting to form the protective member 42 capable of covering the entire slit surface 410 of the pole piece body 41. The "influence of slitting" can include the extrusion force on the protective layer 60 so that the protective layer 60 deforms, and can also include the change in form of the protective layer 60 due to heat.

[0095] In some embodiments, in the first direction x, the size of the protective layer 60 is smaller than the size of the substrate body 50, so that the protective member 42 formed by slitting the protective layer 60 covers the slit surface 410 in most or all of the slit surface 410, to reduce the influence of the protective layer 60 on the surface active substances of the substrate body 50.

[0096] In some embodiments, the protective layer 60 can be a strip structure with a small width size, and the protective layer 60 can extend along the second direction y. When the substrate 500 is slit, the substrate 500 can be fed along the second direction y, and the cutter 70 or the laser acts on the substrate 500, and continuously slits the substrate 500 as the substrate 500 is fed.

[0097] Exemplarily, referring to FIGS. 8-11, in FIG. 8, the substrate 500 is slit by the cutter 70, the cutter 70 is located on the side of the protective layer 60 away from the substrate body 50, and the cutter 70 cuts the substrate 500 along the thickness direction z of the substrate with the slit line 403 as the reference. In FIGS. 9 and 10, the cutter 70 cuts into the substrate 500, and the extrusion force of the cutter 70 can act on the protective layer 60 and the substrate body 50, so that the substrate body 50 is slit into the pole piece body 41 with a suitable size along the slit line 403, and the slit surface 410 is formed based on the slit line 403, and the protective layer 60 deforms along the slit surface 410 under the extrusion force of the cutter 70 to form the protective member 42 covering the slit surface 410, to obtain the pole piece 40 as shown in FIG. 11.

[0098] The technical solutions provided by some embodiments of the present application can, before slitting the substrate 500 of the pole piece 40, set the protective layer 60 on the substrate body 50 and set the protective layer 60 corresponding to the slit line 403, so that, in the process of slitting, the protective layer 60 is formed into the protective member 42 capable of covering the slit surface 410 of the substrate body 50, and the burrs and metal particles generated by slitting are covered, thereby avoiding the exposure of the edge burrs and metal particles of the pole piece 40, effectively reducing the risk of the burrs and metal particles piercing the separator and causing internal short circuit of the battery cell, so that the battery cell has higher reliability, and thus the battery has higher reliability.

[0099] According to some embodiments of the present application, the protective layer 60 includes a polymer layer 61.

[0100] In some embodiments, the protective layer 60 can include a polymer layer 61, and a material of the polymer layer 61 can include a polymer, which can be a high molecular compound. In some embodiments, the polymer layer 61 can be made of plastic, in other embodiments, the polymer can be made of rubber, and in other embodiments, the polymer can be made of fiber. Exemplarily, the polymer layer 61 can be a thermoplastic plastic layer.

[0101] In the above solution, the protective layer 60 is arranged to include the polymer layer 61, which can utilize the physical properties of the polymer to cover the slitting section 410 of the pole piece body 41 by extrusion, deformation, or heating to melt and flow, so as to form the protective member 42 capable of covering burrs and metal particles, effectively reducing the risk of burrs and metal particles piercing the diaphragm and causing internal short circuit of the battery cell, so that the battery cell has higher reliability, and the battery has higher reliability.

[0102] According to some embodiments of the present application, the material of the polymer layer 61 includes at least one of polyethylene terephthalate, polytetrafluoroethylene, polyvinylidene fluoride, polypropylene, polyethylene, polyvinyl chloride, polycarbonate, polyimide, or polyamide-imide.

[0103] Polyethylene terephthalate is also known as PET. Polytetrafluoroethylene is also known as PTFE. Polyvinylidene fluoride is also known as PVDF. Polypropylene is also known as PP. Polyethylene is also known as PE. Polyvinyl chloride is also known as PVC. Polycarbonate is also known as PC. Polyimide is also known as PI. Polyamide-imide is also known as PAI.

[0104] According to some embodiments of the present application, the step S1 of providing the base material 500 includes: hot pressing the protective layer 60 on the surface of the base material body 50.

[0105] In some embodiments, the protective layer 60 includes the polymer layer 61, and a certain temperature and pressure are applied to the protective layer 60 so that the protective layer 60 is bonded to the surface of the base material body 50. Exemplarily, the protective layer 60 is placed on the surface of the base material body 50 corresponding to the slitting line 403, and a preheating roller is used to roll the protective layer 60, so that the protective layer 60 can be hot pressed on the surface of the base material body 50. The preheating roller can refer to a roller with a certain temperature to heat the protective layer 60. The preheating roller can heat the protective layer 60 by resistance heating.

[0106] In the scheme, the protective layer 60 includes the polymer layer 61, the protective layer 60 can be efficiently arranged on the surface of the base body 50 by means of heating and rolling, and the protective layer 60 and the base body 50 have a stable connection relationship, which is beneficial to form the protective member 42 covering the cut surface of the pole piece body 41 when the protective layer 60 is cut, so as to cover the burrs and metal particles, effectively reduce the risk of the burrs and metal particles piercing the diaphragm and causing internal short circuit of the battery monomer, so that the battery monomer has higher reliability, and the battery has higher reliability.

[0107] According to some embodiments of the present application, referring to FIG. 12, which is a schematic view of the protective layer 60 in some embodiments of the present application. The protective layer 60 further includes an adhesive layer 62, which is arranged in a stack with the polymer layer 61 along the thickness direction z of the base. The base 500 is provided, including: the polymer layer 61 is adhered to the surface of the base body 50 through the adhesive layer 62.

[0108] In some embodiments, the protective layer 60 can be a multi-layer structure, for example, the protective layer 60 includes a polymer layer 61 and an adhesive layer 62 arranged in a stack. The polymer layer 61 is adhered to the surface of the base body 50 through the adhesive layer 62.

[0109] In some embodiments, glue is coated on the surface of the polymer layer 61 facing the base body 50, the polymer layer 61 is adhered to the base body 50 through the glue, and the adhesive layer 62 is formed after the glue is dried.

[0110] In the scheme, the polymer layer 61 can be efficiently adhered to the surface of the base body 50 through the adhesive layer 62, so that the polymer layer 61 and the base body 50 have a stable connection relationship, which is beneficial to form the protective member 42 covering the cut surface of the pole piece body 41 when the protective layer 60 is cut, so as to cover the burrs and metal particles, effectively reduce the risk of the burrs and metal particles piercing the diaphragm and causing internal short circuit of the battery monomer, so that the battery monomer has higher reliability, and the battery has higher reliability.

[0111] According to some embodiments of the present application, referring to FIG. 7, the base body 50 includes a current collector 51 and an active material layer 52, along the thickness direction of the base body 50, the active material layer 52 is arranged on the surface of the current collector 51, and the protective layer 60 is arranged on the surface of the active material layer 52 away from the current collector 51.

[0112] The current collector 51 can include a metal current collector, for example, the current collector 51 is a metal foil. In other embodiments, the current collector 51 can be a composite current collector including a metal foil and an intermediate layer sandwiched between two metal foils, and the intermediate layer can be a polymer. In the process of battery manufacturing, in the coating process, the active material is coated on the surface of the current collector 51, and after drying, the active material layer 52 is formed. In some embodiments, the active material layer 52 can be provided on one side of the current collector 51, and the active material layer 52 can also be provided on the opposite two sides of the current collector 51.

[0113] In some embodiments, the active material layer 52 can be centrally provided on the surface of the current collector 51, and can be cut along the central position of the active material layer 52. In the first direction, the current collector 51 has an empty foil area 510 which is not provided with the active material layer 52, and the empty foil area 510 can be used for the formation of the tab 111. For example, the tab 111 is die-cut in the empty foil area 510, or the tab 111 is provided in the empty foil area 510.

[0114] In the above scheme, after the coating process, the protective layer 60 is provided on the surface of the active material layer 52, so that the protective layer 60 is cut to form a protective piece 42 capable of covering the cut surface 410 of the substrate body 50, and the burrs and metal particles generated by cutting the current collector 51 are covered, thereby avoiding the exposure of the edge burrs and metal particles of the tab 40, effectively reducing the risk of burrs and metal particles piercing the separator, causing internal short circuit of the battery cell, making the battery cell have higher reliability, and thus making the battery have higher reliability.

[0115] In other embodiments, the protective layer 60 can be provided between the active material layer 52 and the current collector 51. For example, before the coating process, the protective layer 60 can be provided on the surface of the current collector 51, and then the coating process is performed.

[0116] Or in other embodiments, the substrate body 50 can include the current collector 51, and the protective layer 60 is provided on the surface of the current collector 51, and after the cutting process, the coating process is performed.

[0117] According to some embodiments of the present application, referring to FIGS. 6-11, step S2, cutting the substrate 500, includes: cutting the substrate body 50 into two tab bodies 41 side by side along the first direction x, and cutting the protective layer 60 into two protective pieces 42 respectively covering the cut surfaces 410 of the two tab bodies 41, and the first direction x is perpendicular to the thickness direction z of the substrate.

[0118] The first direction x can be a direction parallel to the width direction of the substrate 500.

[0119] In some embodiments, the base material 500 is slitted along the slitting line 403, and the base material 500 can be slitted into two pole pieces 40. In the process of slitting, the protective piece 42 is also divided into two, respectively forming the protective piece 42 covering the slitting surface 410 of the corresponding pole piece body 41.

[0120] In the above scheme, the base material body 50 is slitted into two pole piece bodies 41 arranged side by side, and the protective layer 60 is divided into two and covers the slitting surface 410 of the corresponding pole piece body 41 respectively to form the protective piece 42, thereby efficiently slitting the pole piece 40, which is conducive to improving the manufacturing efficiency of the battery.

[0121] According to some embodiments of the present application, referring to FIGS. 6 and 7, the step S2 of slitting the base material 500 further includes slitting the base material 500 along the center line of the protective layer 60.

[0122] The center line of the protective layer 60 can refer to the center line of the protective layer 60 parallel to the length direction of the base material 500. In the width direction of the base material 500, the center line of the protective layer 60 divides the protective layer 60 into two parts of the same size.

[0123] The center line of the protective layer 60 can coincide with the slitting line 403, and the base material 500 is slitted, and the protective layer 60 is divided into two parts of the same size due to the slitting, and the two parts of the same size are formed into the protective piece 42 by slitting.

[0124] In the above scheme, by slitting along the center line of the protective layer 60, the protective layer 60 can be slitted into two protective pieces 42 of the same size, which effectively covers the slitting surface 410 of the corresponding pole piece body 41, thereby effectively reducing the risk of burr and metal particle piercing the separator, causing internal short circuit of the battery monomer, so that the battery monomer has higher reliability, and thus the battery has higher reliability.

[0125] According to some embodiments of the present application, referring to FIG. 7, along the thickness direction z of the base material, the size of the base material body 50 is M, and along the first direction x, the size of the protective layer 60 is L, which satisfies 2*M≤L≤2*M+0.5mm.

[0126] M can be the thickness dimension of the base material body 50, and can also be understood as the thickness dimension of the pole piece body 41. L can be the size of the protective layer 60 in the first direction x, and after slitting, the protective layer 60 forms two independent protective pieces 42 in the first direction x.

[0127] Along the thickness direction z of the base material, the size M of the base material body 50 and along the first direction x, the size L of the protective layer 60 can satisfy the following relationship:

[0128] 2*M≤L≤2*M+0.5mm. Exemplarily, L can be 2*M, 2*M+0.05mm, 2*M+0.1mm, 2*M+0.15mm…2*M+0.45mm, 2*M+0.5mm or any value between two adjacent values.

[0129] In the above scheme, the size of the protective layer 60 in the first direction x is set to be not less than twice the thickness of the substrate body 50, so that the protective layer 60 formed by slitting can effectively cover the slitting section 410 of the pole piece body 41, reducing the risk of short circuit of the battery cell caused by burrs and metal particles piercing the diaphragm, so that the battery has higher reliability. The size of the protective layer 60 in the first direction x is set to be not more than twice the thickness of the substrate body 50 plus 0.5mm, which can reduce the influence of the protective layer 42 on the active material of the pole piece 40 or the influence on the conductivity, and reduce the influence on the charge-discharge performance or energy density of the battery. Therefore, by setting the size of the protective layer 60 in the first direction x to be not less than twice the thickness of the substrate body 50 and not more than twice the thickness of the substrate body 50 plus 0.5mm, the reliability, charge-discharge performance or energy density of the battery can be considered.

[0130] According to some embodiments of the present application, the size of the substrate body 50 in the thickness direction z of the substrate is M, and the size of the protective layer 60 in the first direction x is L, satisfying 2*M≤L≤2*M+0.1mm.

[0131] The size M of the substrate body 50 in the thickness direction z of the substrate and the size L of the protective layer 60 in the first direction x can satisfy the following relationship:

[0132] 2*M≤L≤2*M+0.1mm. Exemplarily, L can be 2*M, 2*M+0.01mm, 2*M+0.02mm, 2*M+0.03mm…2*M+0.09mm, 2*M+0.1mm or any value between two adjacent values.

[0133] In the above scheme, the size of the protective layer 60 in the first direction x is set to be not less than twice the thickness of the substrate body 50, so that the protective layer 60 can effectively cover the cutting surface 410 of the pole piece body 41 formed by cutting, thereby reducing the risk of short circuit of the battery cell caused by burrs and metal particles piercing the separator, and making the battery have higher reliability. The size of the protective layer 60 in the first direction x is set to be not more than twice the thickness of the substrate body 50 plus 0.1 mm, which can effectively reduce the influence of the protective layer 42 on the active material of the pole piece 40 or the influence on the electrical conductivity, and effectively reduce the influence on the charge-discharge performance or energy density of the battery. Therefore, by setting the size of the protective layer 60 in the first direction x to be not less than twice the thickness of the substrate body 50 and not more than twice the thickness of the substrate body 50 plus 0.1 mm, the reliability, charge-discharge performance or energy density of the battery can be effectively balanced.

[0134] In some embodiments, the thickness of the protective layer 60 can be not less than 0.001 mm and not more than 1 mm. For example, the thickness of the protective layer 60 can be 0.001 mm, 0.002 mm, 0.003 mm, 0.004 mm, …, 0.9 mm, 1 mm or any value between adjacent two values. By setting the thickness of the protective layer 60 to be not less than 0.001 mm, the protective layer 60 can effectively cover the burrs and metal particles generated by the cutting surface 410 to reduce the risk of internal short circuit of the battery cell, thereby making the battery have high reliability. By setting the thickness of the protective layer 60 to be not more than 1 mm, the influence of the protective layer 60 on the internal space of the battery cell is reduced, and the influence on the mass energy density and volume energy density of the battery cell is reduced.

[0135] According to some embodiments of the present application, please refer to FIGS. 8-11.

[0136] In step S2, the substrate 500 is cut, including:

[0137] The protective layer 60 covers the entire cutting surface 410 of the pole piece body 41 to form the protective layer 42 under the extrusion of the cutting knife 70.

[0138] The cutting knife 70 can refer to a component capable of cutting the substrate 500 into the pole piece 40. In some embodiments, the cutting knife 70 can be a blade with a relatively thin thickness, which can cut the substrate 500.

[0139] Exemplarily, please refer to FIG. 8-FIG. 11, in FIG. 8, the base material 500 is cut by the cutter 70, the cutter 70 is located on the side of the protective layer 60 away from the base material body 50, and the cutter 70 cuts the base material 500 along the thickness direction z of the base material and along the cutting line 403. In FIG. 9 and FIG. 10, the cutter 70 cuts into the base material 500, and the extrusion force of the cutter 70 can act on the protective layer 60 and the base material body 50, so that the base material body 50 is cut along the cutting line 403 into a plurality of pole piece bodies 41 with appropriate sizes, and a cutting surface 410 is formed based on the cutting line 403, and the protective layer 60 is deformed along the cutting surface 410 under the extrusion force of the cutter 70 to form a protective piece 42 covering the entire cutting surface 410, thereby obtaining the pole piece 40 as shown in FIG. 11.

[0140] In some embodiments, the base material 500 is cut by the cutter 70, and the relative positions of the protective layer 60 and the base material body 50 can not be limited, for example, the protective layer 60 can be located below the base material body 50, and the protective layer 60 can also be located above the base material body 50.

[0141] In the above scheme, the base material 500 is cut by the cutter 70, so that the protective layer 60 is deformed along the cutting surface 410 of the pole piece body 41 under the extrusion force of the cutter 70, and is pasted and covers the cutting surface 410 of the pole piece body 41, thereby covering the burrs and metal particles of the cutting surface 410, reducing the risk of the burrs and metal particles piercing the separator and causing internal short circuit of the battery cell, so that the battery cell has higher reliability, and the battery has higher reliability.

[0142] According to some embodiments of the present application, the step S2 of cutting the base material 500 further comprises:

[0143] The cutter 70 is heated, and the base material 500 is cut by the heated cutter 70, and the protective layer 60 is melted and covers the entire cutting surface 410 of the pole piece body 41 to form the protective piece 42 under the heating and extrusion of the cutter 70.

[0144] In some embodiments, the cutter 70 is heated before cutting the base material 500 by the cutter 70, so that the cutter 70 heats the protective layer 60 during cutting the base material 500, so that the protective layer 60 is melted and flows, and the flowing protective layer 60 can be effectively bonded to the entire cutting surface 410 of the pole piece body 41.

[0145] In some embodiments, the cutter 70 can be heated by a heating mechanism, which includes but is not limited to heating the cutter 70 by resistance heating, so that the heating temperature of the cutter 70 to the protective layer 60 can make the protective layer 60 melt and flow. In some embodiments, the heating temperature of the cutter 70 is adjusted by adjusting the power of the heating mechanism to adapt to protective layers 60 with different materials.

[0146] In the above scheme, the base material 500 is cut by the heated cutter 70, so that the protective layer 60 is not only subjected to the pressing force, but also is in a molten state due to heating to effectively cover and firmly adhere to the cut surface 410 of the pole piece body 41, thereby effectively covering the burrs and metal particles of the cut surface 410, effectively reducing the risk of burrs and metal particles piercing the separator, causing internal short circuit of the battery cell, so that the battery cell has higher reliability, and thus the battery has higher reliability.

[0147] According to some embodiments of the present application, the heating temperature of the cutter 70 is not less than 100 degrees Celsius and not more than 350 degrees Celsius.

[0148] In some embodiments, the heating temperature of the cutter 70 can be not less than 100 degrees Celsius and not more than 350 degrees Celsius, for example, the heating temperature of the cutter 70 can be 100 degrees Celsius, 150 degrees Celsius, 200 degrees Celsius, 250 degrees Celsius, 300 degrees Celsius, or any value between any two adjacent values.

[0149] For example, when the material of the protective layer 60 includes polyethylene terephthalate, the heating temperature of the cutter 70 can be 200 degrees Celsius to 280 degrees Celsius. When the material of the protective layer 60 includes polytetrafluoroethylene, the heating temperature of the cutter 70 can be 280 degrees Celsius to 350 degrees Celsius. When the material of the protective layer 60 includes polyvinylidene fluoride, the heating temperature of the cutter 70 can be 100 degrees Celsius to 145 degrees Celsius. When the material of the protective layer 60 includes polypropylene, the heating temperature of the cutter 70 can be 130 degrees Celsius to 185 degrees Celsius. When the material of the protective layer 60 includes polyvinyl chloride, the heating temperature of the cutter 70 can be 150 degrees Celsius to 205 degrees Celsius. When the material of the protective layer 60 includes polycarbonate, the heating temperature of the cutter 70 can be 200 degrees Celsius to 240 degrees Celsius. When the material of the protective layer 60 includes polyimide, the heating temperature of the cutter 70 can be 250 degrees Celsius to 350 degrees Celsius. When the material of the protective layer 60 includes polyamide-imide, the heating temperature of the cutter 70 can be 200 degrees Celsius to 300 degrees Celsius.

[0150] In some embodiments, the heating temperature of the cutter 70 can be adjusted, and the adjustment range can be not less than 100 degrees Celsius and not more than 350 degrees Celsius to adapt to different needs. For example, the higher the temperature, the more easily the protective layer 60 can be molten to flow along the cut surface 410 of the pole piece body 41 to effectively cover the cut surface 410; but too high a temperature can cause the protective layer 60 to carbonize and vaporize, affecting the protection effect; or by adjusting the heating temperature, different materials of the protective layer 60 can be applied.

[0151] In the above scheme, by setting the temperature at which the cutter 70 is heated to be not less than 100 degrees Celsius, the protective layer 60 can be effectively heated so that the protective layer 60 melts to improve the effect of coating the slitting section 410, thereby improving the reliability of the battery; by setting the temperature at which the cutter 70 is heated to be not more than 100 degrees Celsius, the risk of the protective layer 60 vaporizing due to an overheated temperature can be effectively reduced, so that the protective layer 60 melts to improve the effect of coating the slitting section 410, thereby improving the reliability of the battery. For this reason, by setting the temperature at which the cutter 70 is heated to be not less than 100 degrees Celsius and not more than 100 degrees Celsius, the risk of burrs and metal particles piercing the separator, leading to internal short circuits of the battery monomer, can be effectively reduced, so that the battery monomer has high reliability, and thus the battery has high reliability.

[0152] According to some embodiments of the present application, after performing step S2 of slitting the substrate 500, the method further comprises the step of heating the protective member 42 so that the protective member 42 melts.

[0153] In some embodiments, after the cutter 70 slits the substrate 500, the pole piece 40 formed after slitting can be heated to heat the protective member 42, so that the protective member 42 of the pole piece 40 melts and flows, thereby forming a good coverage on the slitting section 410 of the pole piece body 41.

[0154] In some embodiments of the present application, the way of heating the pole piece 40 is not limited, for example, the pole piece 40 can be heated by a heated roll, and for another example, the pole piece 40 can be heated by passing into an oven.

[0155] In some embodiments, the heating temperature of the protective member 42 can be determined based on the material of the protective layer 60, for example, when the material of the protective layer 60 includes polyethylene terephthalate, the heating temperature of the cutter 70 can be 200 degrees Celsius to 280 degrees Celsius. When the material of the protective layer 60 includes polytetrafluoroethylene, the heating temperature of the cutter 70 can be 280 degrees Celsius to 350 degrees Celsius. When the material of the protective layer 60 includes polyvinylidene fluoride, the heating temperature of the cutter 70 can be 100 degrees Celsius to 145 degrees Celsius. When the material of the protective layer 60 includes polypropylene, the heating temperature of the cutter 70 can be 130 degrees Celsius to 185 degrees Celsius. When the material of the protective layer 60 includes polyvinyl chloride, the heating temperature of the cutter 70 can be 150 degrees Celsius to 205 degrees Celsius. When the material of the protective layer 60 includes polycarbonate, the heating temperature of the cutter 70 can be 200 degrees Celsius to 240 degrees Celsius. When the material of the protective layer 60 includes polyimide, the heating temperature of the cutter 70 can be 250 degrees Celsius to 350 degrees Celsius. When the material of the protective layer 60 includes polyamide-imide, the heating temperature of the cutter 70 can be 200 degrees Celsius to 300 degrees Celsius.

[0156] In the above scheme, by heating the protective member 42, the protective member 42 can be caused to melt and flow, so that the thickness of the protective member 42 is uniform, and the protective member 42 further has a good covering effect on the cut surface 410 of the tab body 41, thereby effectively reducing the risk of burrs and metal particles piercing the separator, causing internal short circuit of the battery cell, so that the battery cell has high reliability, and the battery has high reliability.

[0157] According to some embodiments of the present application, see FIGS. 13-15, which are schematic diagrams of the manufacturing process of the tab 40 in some embodiments of the present application.

[0158] In step S22, the base material 500 is cut, including:

[0159] By laser cutting the base material 500, the protective layer 60 is melted and covers the entire cut surface 410 of the tab body 41 under the action of the laser to form the protective member 42.

[0160] In some embodiments, the base material 500 is cut by laser cutting.

[0161] For example, the laser is generated by a laser device 80, which is located on the side of the protective layer 60 away from the base material body 50. Along the thickness direction z of the base material, the laser device 80 emits laser to the base material 500 based on the cutting line 403, and the laser acts on the base material. In FIG. 14, the laser acts on the base material 500, so that the base material body 50 is cut along the cutting line 403 into tab bodies 41 of appropriate size, and the protective layer 60 is melted and flows under the action of the laser to cover the cut surface 410 bonded to the cut surface 410, thereby forming the protective member 42, and obtaining the tab 40 as shown in FIG. 15.

[0162] In some embodiments, the laser device 80 can provide laser with a pulse width of 200 ns, a period of 400 ns, and an average power of 1 KW.

[0163] In the above scheme, by laser cutting the base material 500, on the one hand, the base material body 50 and the protective layer 60 can be accurately cut, improving the accuracy of the size of the tab 40; on the other hand, the protective layer 60 can be caused to melt and adhere to the cut surface 410 of the tab body 41 due to the high temperature generated by the laser when cutting, thereby covering the burrs and metal particles on the cut surface 410, reducing the risk of burrs and metal particles piercing the separator, causing internal short circuit of the battery cell, so that the battery cell has high reliability, and the battery has high reliability.

[0164] According to some embodiments of the present application, along the direction of gravity, the protective layer 60 is located above the base material body 50.

[0165] In some embodiments, the substrate 500 is laser slitting in a horizontal posture, which can refer to placing the substrate body 50 on a horizontal plane, and the protective layer 60 is arranged on the upper surface of the substrate body 50.

[0166] In the above scheme, by arranging the protective layer 60 above the substrate body 50, the molten protective layer 60 can effectively flow along the slitting section 410 under the action of gravity, thereby effectively covering the slitting section 410, covering the burrs and metal particles of the slitting section 410, reducing the risk of burrs and metal particles piercing the separator, causing internal short circuit of the battery cell, making the battery cell have higher reliability, and thus making the battery have higher reliability.

[0167] According to some embodiments of the present application, a manufacturing method of an electrode sheet is provided, which comprises the following steps:

[0168] S1, providing a substrate 500, the substrate 500 comprising a substrate body 50 and a protective layer 60, the protective layer 60 being arranged on the surface of the substrate body 50 along the thickness direction z of the substrate;

[0169] S2, slitting the substrate 500 to divide the substrate body 50 into at least one electrode sheet body 41, and the protective layer 60 into a protective piece 42 covering the entire slitting section 410 of the at least one electrode sheet body 41.

[0170] In the step S1 of providing the substrate 500, the protective layer 60 can be arranged on the surface of the substrate body 50 in the form of an adhesive tape. The protective layer 60 can include a polymer layer 61, which is bonded to the surface of the substrate body 50 and corresponds to the slitting line 403. The center line of the polymer layer 61 coincides with the slitting line 403. The width of the protective layer 60 is greater than 2 times the thickness of the substrate body 50, and the width of the protective layer 60 is less than 2 times the thickness of the substrate body 50 plus 0.1 mm. The thickness of the protective layer 60 can be 0.001 mm to 1 mm.

[0171] In some embodiments, in the step S2 of slitting the substrate 500, the slitting can be performed by a cutter 70. Please refer to FIGS. 6, 8-11.

[0172] The cutter 70 is located on the side of the protective layer 60 away from the substrate body 50, and cuts the substrate 500 along the thickness direction z of the substrate with the slitting line 403 as the reference. The cutter 70 can be heated so that the temperature of the cutter 70 is between 100 degrees Celsius and 350 degrees Celsius.

[0173] The cutter 70 cuts into the base material 500, and the extrusion force of the cutter 70 can act on the protective layer 60 and the base material body 50, so that the protective layer 60 and the base material body 50 are divided into two, the base material body 50 is cut along the cutting line 403 into a suitable size pole piece body 41, and a cutting section 410 is formed based on the cutting line 403, and the protective layer 60 is deformed along the cutting section 410 under the action of the extrusion force of the cutter 70, and at the same time, the protective layer 60 is heated by the cutter 70, so that the protective layer 60 melts and flows, effectively bonding and covering the entire cutting section 410 of the pole piece body 41, forming a protective piece 42, and obtaining a pole piece 40 as shown in FIG. 11.

[0174] In some embodiments, after the step S2 of cutting the base material 500, the obtained pole piece 40 can be heated, so that the protective piece 42 of the pole piece 40 flows and spreads after being heated and melted, forming a good coverage on the cutting section 410 of the pole piece body 41, and reducing the thickness of the protective piece 42 partially covering the surface of the pole piece body 41.

[0175] In another embodiment, in the step S2 of cutting the base material 500 along the cutting line 403, the cutting can be performed by laser.

[0176] Please refer to FIG. 6 and FIG. 13-15.

[0177] The protective layer 60 is arranged on the upper surface of the base material body 50, the laser device 80 is located on the side of the protective layer 60 away from the base material body 50, and the laser device 80 emits laser to the base material 500 along the thickness direction z of the base material as a reference of the cutting line 403. The laser acts on the base material 500, so that the base material body 50 is cut along the cutting line 403 into a suitable size pole piece body 41, and a cutting section 410 is formed based on the cutting line 403, and the protective layer 60 is melted and flows to cover and bond to the cutting section 410 under the action of the laser, thereby forming a protective piece 42, and obtaining a pole piece 40 as shown in FIG. 15.

[0178] The above scheme, before cutting the base material 500 of the pole piece 40, by arranging the protective layer 60 on the base material body 50 and arranging the protective layer 60 corresponding to the cutting line 403, the protective layer 60 can be formed into a protective piece 42 capable of covering the cutting section 410 of the base material body 50 during cutting, and the burrs and metal particles generated by cutting the base material body 50 are covered, thereby avoiding the exposure of the edge burrs and metal particles of the pole piece 40, effectively reducing the risk of the burrs and metal particles piercing the separator and causing internal short circuit of the battery cell, so that the battery cell has higher reliability, and the battery has higher reliability.

[0179] The above descriptions are only the preferred embodiments of the present application, and are not intended to limit the present application. The present application can have various modifications and changes for those skilled in the art. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for manufacturing a pole piece, wherein: The method comprises the following steps: Providing a substrate, the substrate comprising a substrate body and a protective layer, wherein the protective layer is disposed on a surface of the substrate body along a thickness direction of the substrate; The substrate is cut into at least one pole piece body, and the protective layer is cut into protective pieces covering the entire cut surface of the at least one pole piece body.

2. The method for manufacturing a pole piece according to claim 1, wherein: The protective layer includes a polymer layer.

3. The method for manufacturing a pole piece according to claim 2, wherein: The material of the polymer layer includes at least one of polyethylene terephthalate, polytetrafluoroethylene, polyvinylidene fluoride, polypropylene, polyethylene, polyvinyl chloride, polycarbonate, polyimide or polyamide-imide.

4. The method for manufacturing a pole piece according to claim 2 or 3, wherein: The providing of a substrate comprises: The protective layer is hot pressed onto the surface of the substrate body.

5. The method for manufacturing a pole piece according to any one of claims 2 to 4, wherein: The protective layer further comprises an adhesive layer, and the adhesive layer and the polymer layer are stacked along the thickness direction of the substrate; The providing of a substrate comprises: The polymer layer is adhered to the surface of the substrate body through the adhesive layer.

6. The method for manufacturing a pole piece according to any one of claims 2 to 5, wherein: The substrate body includes a current collector and an active material layer. Along the thickness direction of the substrate body, the active material layer is arranged on the surface of the current collector, and the protective layer is arranged on the surface of the active material layer away from the current collector.

7. The method for manufacturing a pole piece according to any one of claims 2 to 6, wherein: The step of cutting the substrate comprises: The substrate body is cut into two pole piece bodies arranged side by side along a first direction, and the protective layer is cut into two protective members respectively covering the cut surfaces of the two pole piece bodies. The first direction is perpendicular to the thickness direction of the substrate.

8. The method for manufacturing a pole piece according to claim 7, wherein: The cutting of the substrate further comprises: The substrate is cut along the center line of the protective layer.

9. The method for manufacturing a pole piece according to claim 7 or 8, wherein: Along the thickness direction of the substrate, the size of the substrate body is M, and along the first direction, the size of the protective layer is L, satisfying 2*M≤L≤2*M+0.5mm.

10. The method for manufacturing a pole piece according to claim 9, wherein: Along the thickness direction of the substrate, the size of the substrate body is M, and along the first direction, the size of the protective layer is L, satisfying 2*M≤L≤2*M+0.1mm.

11. The method for manufacturing a pole piece according to any one of claims 2 to 10, wherein: The step of cutting the substrate comprises: The substrate is cut by a cutter, and the protective layer covers the entire cut surface of the pole piece body under the pressure of the cutter to form the protective member.

12. The method for manufacturing a pole piece according to claim 11, wherein: The cutting of the substrate further comprises: The cutter is heated and the substrate is cut by the heated cutter. The protective layer melts under the heating and pressing action of the cutter and covers the entire cut surface of the electrode body to form the protective member.

13. The method for manufacturing a pole piece according to claim 12, wherein: The cutting blade is heated at a temperature not less than 100 degrees Celsius and not more than 350 degrees Celsius.

14. The method for manufacturing a pole piece according to claim 12 or 13, wherein: After performing the cutting of the substrate, the method further comprises the steps of: The protective member is heated to melt the protective member.

15. The method for manufacturing a pole piece according to any one of claims 2 to 10, wherein: The cutting of the substrate further comprises: The substrate is cut by laser, and the protective layer is melted under the action of the laser and covers the entire cut surface of the pole piece body to form the protective member.

16. The method for manufacturing a pole piece according to claim 15, wherein: Along the direction of gravity, the protective layer is located above the substrate body.

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