CN118054020A

CN118054020A - Pole piece, battery cell, battery, electricity utilization device and manufacturing method

Info

Publication number: CN118054020A
Application number: CN202410419419.4A
Authority: CN
Inventors: 杨俭; 王耀辉; 夏忠辉; 邓博楷; 黄思应
Original assignee: Contemporary Amperex Technology Co Ltd
Current assignee: Contemporary Amperex Technology Co Ltd
Priority date: 2024-04-09
Filing date: 2024-04-09
Publication date: 2024-05-17

Abstract

The application discloses a pole piece, a battery monomer, a battery, an electric device and a manufacturing method. The pole piece comprises a composite current collector and a first active material layer. The composite current collector comprises a current collector body and a connecting part which are mutually connected along a first direction, wherein the first direction is mutually perpendicular to the thickness direction of the current collector body. Along the first direction, the connecting part is provided with a cutting surface which is far away from the current collector body, and along the thickness direction of the composite current collector, the current collector body is provided with a first surface and a third surface which are opposite to each other, the connecting part is provided with a second surface, and the first surface and the second surface jointly form a first coating area. The first active material layer is disposed in the first coating region. The connecting portion comprises a first connecting piece and a connecting body which are connected with each other, the connecting body is connected with the end face of the current collector body along the first direction, and the first connecting piece protrudes out of the connecting body along the first direction and is connected to the first surface or the third surface. The technical scheme provided by the application can effectively improve the reliability of the battery.

Description

Pole piece, battery cell, battery, electricity utilization device and manufacturing method

Technical Field

The application relates to the technical field of batteries, in particular to a pole piece, a battery cell, a battery, an electric device and a manufacturing method.

Background

Energy conservation and emission reduction are key to sustainable development of the automobile industry, and electric vehicles become an important component of sustainable development of the automobile industry due to the energy conservation and environmental protection advantages of the electric vehicles. For electric vehicles, battery technology is an important factor in the development of the electric vehicles.

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

Disclosure of Invention

The application provides a pole piece, a battery monomer, a battery, an electricity utilization device and a manufacturing method.

In a first aspect, the present application provides a pole piece comprising a composite current collector and a first active material layer. The composite current collector comprises a current collector body and a connecting part which are mutually connected along a first direction, wherein the first direction is mutually perpendicular to the thickness direction of the current collector body. Along the first direction, the connecting portion has the face of cutting that deviates from in the mass flow body, along the thickness direction of compound mass flow body, the mass flow body has first surface and the third surface that are relative each other, and the connecting portion has the second surface, and first surface and second surface homonymy set up and interconnect, and first surface and second surface form first coating district jointly. The first active material layer is disposed in the first coating region. The connecting part is made of nonmetallic materials, comprises a first connecting piece and a connecting body which are connected with each other, the connecting body is connected with the end face of the current collector body along the first direction, the connecting body and the current collector body are arranged side by side along the first direction, and the first connecting piece protrudes out of the connecting body and is connected with the first surface or the third surface.

In the scheme, under the current collecting and conducting effects of the current collector body, the connecting part and the current collector body are arranged to jointly bear the first active material layer, and in the slitting process of the manufacturing process of the battery, the cutter can act on the connecting part to form a tangential plane without cutting the current collector body made of metal materials, so that the problems of metal particles and burrs generated by slitting can be fundamentally avoided, the risk of internal short circuit of the battery cell caused by the penetration of the isolating film by the metal particles or burrs is effectively reduced, and the reliability of the battery is further high; meanwhile, through the arrangement of the first connecting piece which is convex, the connection relation between the connecting part and the current collector body is stable, so that the first active material layer is stably arranged on the composite current collector, the risk that the first active material layer is separated from the composite current collector is reduced, the reliability of the battery is high, and the reliability of the battery is further high.

According to some embodiments of the application, the connecting portion further comprises a second connecting member connected to the connecting body, the first connecting member is connected to the first surface, and the second connecting member protrudes from the connecting body and is connected to the third surface along the first direction.

In the above scheme, through setting up convex first connecting piece and second connecting piece, can make the relation of connection stable between connecting portion and the mass flow body to make first active material layer set up on compound mass flow body steadily, reduce first active material layer and break away from in compound mass flow body's risk, make the free reliability of battery high, and then make the reliability of battery high.

According to some embodiments of the application, the first active material layer has a first side in a first direction, the first side being disposed on the same side as the parting plane. The first side surface is coplanar with the cutting surface, or along the first direction, the cutting surface protrudes out of the plane where the first side surface is located.

In some embodiments, the first side surface and the dividing surface are arranged in a coplanar manner, so that the amount of the first active material layer on the composite current collector can be increased, and the volume and the mass energy density of the battery can be improved. In other embodiments, the split surface exceeds the plane where the first side surface is located, so that the connecting portion provides a larger supporting surface for the first active material layer, the risk that the active material layer is separated from the composite current collector is reduced, the battery cell has higher reliability, and the reliability of the battery is high.

According to some embodiments of the application, the first surface comprises, in the first direction, a first empty foil area and a first connection area connected to each other, the first connection area being closer to the second surface than the first empty foil area, the first connection area and the second surface together forming a first coated area.

In the scheme, the first empty foil area is arranged so as to facilitate the output and input of current.

According to some embodiments of the application, the pole piece further comprises a second active material layer. Along the thickness direction of the composite current collector, the current collector body is provided with a third surface, the third surface and the first surface are opposite to each other, the connecting part is provided with a fourth surface, the fourth surface and the second surface are opposite to each other, the third surface and the fourth surface are arranged on the same side and are connected with each other, the third surface and the fourth surface jointly form a second coating area, and the second active material layer is arranged in the second coating area.

In the scheme, the second active material layers are arranged, so that the active material layers are respectively arranged on the two sides of the composite current collector, the improvement of the electric capacity of the battery monomer is facilitated, the battery monomer has higher volume energy density, and the battery has higher volume energy density.

According to some embodiments of the application, the projections of the first active material layer and the second active material layer coincide with each other in the thickness direction of the composite current collector.

In the above scheme, through setting up the projection on first active material layer and second active material layer to coincide each other for at the in-process of cutting the pole piece, no matter acquire the datum point of judging the position of cutting with first active material layer or second active material layer, can both effectively and accurately find the position of cutting, thereby improve and cut efficiency, reduce and cut the risk that the cutter produced metal particle and burr to the mass flow body because of cutting the deviation, make the single reliability of battery high, the reliability of battery is high.

According to some embodiments of the application, the dimension of the connection portion is not less than 0.5mm and not more than 5mm in the first direction.

In the above scheme, the size of the connecting part in the first direction is set to be not smaller than 0.5mm, so that the connecting part can provide a larger supporting area for the active material layer, the risk that the first active material layer is separated from the composite current collector is reduced, the probability that a cutter cuts the current collector body is reduced, the slitting quality is improved, the problem of metal particles and burrs generated by slitting is fundamentally avoided, the risk that the metal particles or burrs pierce through the isolating film to cause internal short circuit of the battery is effectively reduced, and the reliability of the battery is further high; by setting the dimension of the connecting portion in the first direction to be not more than 5mm, the risk that the connecting portion occupies too much space of the current collector body, resulting in a reduction in conductivity of the composite current collector can be reduced; for this reason, by setting the dimension of the connecting portion in the first direction to not less than 0.5 and not more than 5mm, the supporting effect on the active material layer, the slitting quality, and the conductivity of the composite current collector can be simultaneously achieved.

According to some embodiments of the application, the material of the current collector body comprises copper or aluminum.

According to some embodiments of the application, the current collector body comprises a metallic conductive layer, or, the current collector body comprises a metallic conductive layer and a polymer layer, the polymer layer being sandwiched between the two metallic conductive layers in the thickness direction of the composite current collector.

In the scheme, the polymer layer is arranged, so that the density of the current collector body can be reduced on one hand, the mass density of the battery monomer is improved, and the mass density of the battery is further improved; on the other hand, the material cost of the current collector body can be effectively reduced, and the manufacturing cost of the battery is reduced; on the other hand, due to the arrangement of the polymer layer, the breaking efficiency can be generated when the battery is punctured, so that the reliability of the battery can be effectively improved; in still another aspect, when the connecting portion is made of a hot-melt material, the polymer layer and the connecting portion are connected with good effect, so that the current collector body and the connecting portion are combined stably, and are not easy to break, and the battery has high reliability.

According to some embodiments of the application, the material of the connecting portion comprises a hot melt adhesive, and the connecting portion is connected to the current collector body by hot pressing.

In the above scheme, the connecting part is made of the material comprising the hot melt adhesive, so that the connecting part and the current collector body form a stable connection relationship under the action of hot pressing.

According to some embodiments of the application, the material of the connecting portion includes at least one of polyurethane hot melt adhesive, copolyester hot melt adhesive, vinyl acetate copolymer, copolyamide, polyolefin or acrylic acid acetate copolymer.

In a second aspect, the present application also provides a battery cell comprising an electrode assembly comprising a positive electrode sheet and a negative electrode sheet, at least one of the positive and negative electrode sheets being a sheet as provided in the first aspect.

In a third aspect, the present application also provides a battery comprising the battery cell provided in the second aspect.

In a fourth aspect, the present application further provides an electric device, where the electric device includes the battery cell provided in the second aspect, and the battery cell is used to provide electric energy.

In a fifth aspect, the present application also provides a method for manufacturing a pole piece, including the steps of:

Providing a composite current collector, arranging at least two current collector bodies at intervals along a first direction and forming a gap penetrating along a second direction, wherein a connecting part is arranged in the gap, two adjacent current collector bodies are connected through the connecting part to form the composite current collector, the first direction is mutually perpendicular to the thickness direction of the current collector bodies, and the second direction is parallel to the thickness direction of the current collector bodies;

Coating active substances on the surface of the current collector body and the surface of the connecting part along the thickness direction of the composite current collector to obtain a pole piece material belt;

and cutting the pole piece material belt along a second direction corresponding to the connecting part to obtain at least two pole pieces.

In the scheme, the connecting parts are arranged between the two adjacent current collector bodies to form the composite current collector, so that on one hand, when the pole piece material belt is cut, the cutter bit can fall on the position where the connecting parts are located, and the current collector body is not cut, thereby fundamentally avoiding the problems of metal particles and burrs generated by cutting, effectively reducing the risk of internal short circuit of the battery cell caused by the penetration of the isolating film by the metal particles or burrs, and further ensuring high reliability of the battery; on the other hand, the active material can be coated on the current collector body, the connecting part with lower cost and density and supported by the current collector body and the connecting part together, so that the material cost of the pole piece can be reduced, the cost of the battery cell can be reduced, the cost of the battery can be further reduced, the quality of the battery can be effectively reduced, the mass density of the battery cell is high, and the mass density of the battery is further high.

According to some embodiments of the application, the material of the connection portion comprises a hot melt adhesive. Providing a composite current collector comprising:

The hot melt adhesive is positioned between the two adjacent current collector bodies and is lapped on the surfaces of the two adjacent current collector bodies along the thickness direction of the composite current collector, and the hot melt adhesive is hot pressed, so that the hot melt adhesive is melted and enters the gap to form the connecting part.

In the scheme, the material of the connecting part is set to comprise hot melt adhesive, and the connecting part can be efficiently formed between two adjacent current collector bodies through a simple hot pressing process, so that the manufacturing efficiency of the composite current collector is high.

According to some embodiments of the application, there is provided a composite current collector comprising:

along the thickness direction of the composite current collector, two opposite sides of two adjacent current collector bodies are respectively provided with hot melt adhesives.

In the above scheme, through being provided with the hot melt adhesive respectively in the both sides that are opposite each other of two adjacent collector bodies, can make the hot melt adhesive when melting, get into the clearance between two adjacent collector bodies by two adjacent collector bodies's opposite each other both sides evenly, on the one hand, make the structural relationship between two adjacent collector bodies and the connecting portion stable, on the other hand, make the hot melt adhesive melt the partial connecting portion thickness that forms after the formation adhere to collector body surface even, thereby make the active material layer set up the surface at collector body and connecting portion steadily.

the hot melt adhesive has a center line parallel to the second direction, and the distance between the center lines of two hot melt adhesives located on two opposite sides of the adjacent two current collector bodies in the first direction is not more than 0.5mm.

In the scheme, the offset distance of the central lines of the two hot melt adhesives positioned at the two sides of the current collector body is not more than 0.5mm, so that the hot melt adhesives can uniformly enter the gap between the two adjacent current collector bodies from the two opposite sides of the two adjacent current collector bodies when melting, the surface flatness of the composite current collector body is high, and the active substances are favorably coated on the surface of the composite current collector body.

The foregoing description is only an overview of the embodiments of the present application, and is intended to be implemented in accordance with the teachings of the present application, as it is to be understood that the following detailed description of the application is intended to provide a better understanding of the present application.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic illustration of a vehicle in some embodiments of the application;

Fig. 2 is an exploded perspective view of a battery provided in some embodiments of the application;

Fig. 3 is an exploded perspective view of a battery cell according to some embodiments of the present application;

FIG. 4 is a schematic illustration of a pole piece in some embodiments of the application;

FIG. 5 is a schematic illustration of a composite current collector in some embodiments of the application;

FIG. 6 is a schematic illustration of a pole piece in other embodiments of the present application;

FIG. 7 is a flow chart of a method of manufacturing a pole piece in some embodiments of the application;

FIG. 8 is a schematic illustration of a process for manufacturing a composite current collector in accordance with some embodiments of the application;

Fig. 9 is a schematic view of two current collector bodies and an adhesive tape in some embodiments of the application;

FIG. 10 is a schematic view of a process for manufacturing a composite current collector according to other embodiments of the application;

Fig. 11 is a schematic view of two current collector bodies and two tapes in further embodiments of the application;

FIG. 12 is a schematic view of a composite current collector in accordance with some embodiments of the application;

FIG. 13 is a schematic illustration of a pole piece strip in some embodiments of the application;

FIG. 14 is a schematic illustration of a pole piece strip after slitting in some embodiments of the present application;

fig. 15 is a schematic view of a current collector body and tape according to further embodiments of the present application;

Fig. 16 is a schematic view of a current collector body and tape according to further embodiments of the present application;

Fig. 17 is a schematic view of a current collector body and a connection portion according to other embodiments of the present application;

FIG. 18 is a schematic view of a pole piece strip in accordance with further embodiments of the present application;

fig. 19 is a schematic view of a pole piece strip after being slit according to another embodiment of the present application.

Icon: 400-pole piece; 40-composite current collector; 41-a current collector body; 410-a first surface; 4100—a first empty foil area; 4101—a first connection region; 411-a third surface; 412-a metal conductive layer; 413-a polymer layer; 42-connecting part; 420-slicing; 421-a second surface; 422-fourth surface; 423-a first connector; 424-connecting the body; 425-a second connector; 43-a first coating zone; 50-a first active material layer; 51-a first side; 60-a second active material layer; 70-adhesive tape; 71-a heat roller; 72-a tape roller; 80-pole piece material belts; y-the thickness direction of the composite current collector; x-a first direction; z-a third direction; 10-battery cell; 11-an electrode assembly; 111-electrode lugs; 12-a housing; 120-a housing; 121-end caps; 13-electrode terminals; 14-an adapter; 100-cell; 30-a box body; 31-upper box body; 32-lower box body; 1000-vehicle; 200-a controller; 300-motor.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present application more apparent, the technical solutions of the embodiments of the present application will be clearly described below with reference to the accompanying drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments of the present application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having" and any variations thereof in the description of the application and the claims and the description of the drawings above are intended to cover a non-exclusive inclusion. The terms first, second and the like in the description and in the claims or in the above-described figures, are used for distinguishing between different objects and not necessarily for describing a particular sequential or chronological order.

Reference in the specification to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.

In the description of the present application, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "attached" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art according to the specific circumstances.

The term "and/or" in the present application is merely an association relation describing the association object, and indicates that three kinds of relations may exist, for example, a and/or B may indicate: a exists alone, A and B exist together, and B exists alone. In the present application, the character "/" generally indicates that the front and rear related objects are an or relationship.

In the embodiments of the present application, the same reference numerals denote the same components, and detailed descriptions of the same components are omitted in different embodiments for the sake of brevity. It should be understood that the thickness, length, width, etc. dimensions of the various components in the embodiments of the application shown in the drawings, as well as the overall thickness, length, width, etc. dimensions of the integrated device, are merely illustrative and should not be construed as limiting the application in any way.

The term "plurality" as used herein refers to two or more (including two).

In the present application, the battery cells may 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, which is not limited in the embodiment of the present application. The battery cell may be in a cylindrical shape, a flat shape, a rectangular parallelepiped shape, or other shapes, which is not limited in this embodiment of the application.

Reference to a battery in accordance with an embodiment of the present application refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. The battery generally includes a case for enclosing one or more battery cells. The case body can prevent liquid or other foreign matters from affecting the charge or discharge of the battery cells.

The battery cell comprises an electrode assembly and electrolyte, wherein the electrode assembly consists of a positive plate, a negative plate and a separation membrane. The battery cell mainly relies on metal ions to move between the positive and negative electrode plates to operate. The positive plate comprises a positive electrode current collector and a positive electrode active material layer, the positive electrode active material layer is coated on the surface of the positive electrode current collector, the positive electrode current collector without the positive electrode active material layer protrudes out of the positive electrode current collector coated with the positive electrode active material layer, and the positive electrode current collector without the positive electrode active material layer is used as a positive electrode lug. Taking a lithium ion battery as an example, the material of the positive electrode current collector may be aluminum, and the positive electrode active material may be lithium cobaltate, lithium iron phosphate, ternary lithium, lithium manganate or the like. The negative electrode sheet comprises a negative electrode current collector and a negative electrode active material layer, wherein 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 out of the negative electrode current collector coated with the negative electrode active material layer, and the negative electrode current collector without the negative electrode active material layer is used as a negative electrode lug. The material of the negative electrode current collector may be copper, and the negative electrode active material may be carbon, silicon, or the like. The material of the separator may be PP (polypropylene) or PE (polyethylene). In addition, the electrode assembly may be a roll-to-roll structure or a lamination structure, and embodiments of the present application are not limited thereto.

The development of battery technology is 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 needs to be considered. In the manufacturing process of the battery, the size of the battery monomer can be produced according to the requirement, and the pole piece material belt is cut to obtain a plurality of pole pieces with the sizes meeting the requirement. However, the current collector is generally made of a metal material, such as aluminum or copper, and burrs and metal particles generated during the pole piece slitting process of the metal current collector may puncture the isolating film, so that the positive electrode and the negative electrode of the battery cell are shorted, high-voltage breakdown and even thermal runaway risks are generated, and the reliability of the battery is affected.

In view of this, in order to improve the problem of low reliability of the battery caused by burrs generated when the pole piece is cut, some embodiments of the present application provide a pole piece including a composite current collector and a first active material layer. The composite current collector comprises a current collector body and a connecting part which are mutually connected along a first direction, the first direction is mutually perpendicular to the thickness direction of the current collector body, the connecting part is provided with a cutting surface which is far away from the current collector body along the first direction, the current collector body is provided with a first surface along the thickness direction of the composite current collector, the connecting part is provided with a second surface, the first surface and the second surface are arranged on the same side and are mutually connected, and the first surface and the second surface jointly form a first coating area. The first active material layer is disposed in the first coating region.

In the above scheme, under the collecting and conducting actions of the current collector body, the connecting part and the current collector body are arranged to jointly bear the first active material layer, in the slitting process of the manufacturing process of the battery, the cutter can act on the connecting part to form a tangential plane, and the current collector body made of metal materials is not cut, so that the problems of metal particles and burrs generated by slitting can be fundamentally avoided, the risk of internal short circuit of the battery monomer caused by puncturing of the isolating film by the metal particles or burrs is effectively reduced, and the reliability of the battery is further high.

The technical scheme described by the embodiment of the application is suitable for battery monomers, batteries and power utilization devices using the batteries.

The electric device can be a vehicle, a mobile phone, a portable device, a notebook computer, a ship, a spacecraft, an electric toy, an electric tool and the like. Spacecraft including airplanes, rockets, space planes, spacecraft, and the like; the electric toy includes fixed or mobile electric toys, such as a game machine, an electric car toy, an electric ship toy, and an electric airplane toy; power tools include metal cutting power tools, grinding power tools, assembly power tools, and railroad power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete shakers, and electric planers, among others. The embodiment of the application does not limit the electric device in particular.

For convenience of explanation, the following examples will be described taking an electric device as an example of a vehicle.

Referring to fig. 1, fig. 1 is a schematic diagram of a vehicle 1000 according to some embodiments of the application. The vehicle 1000 may be a fuel oil vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or a range-extended vehicle. The battery 100 is provided in the interior of the vehicle 1000, and the battery 100 may be provided at the bottom or the head or the tail of the vehicle 1000. The battery 100 may be used for power supply of the vehicle 1000, for example, the battery 100 may be used as an operating power source of the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300, the controller 200 being configured to control the battery 100 to power the motor 300, for example, for operating power requirements during start-up, navigation, and travel of the vehicle 1000.

In some embodiments of the present application, battery 100 may not only serve as an operating power source for vehicle 1000, but may also serve as a driving power source for vehicle 1000, instead of or in part instead of fuel oil or natural gas, to provide driving power for vehicle 1000.

Referring to fig. 2, fig. 2 is an exploded perspective view of a battery 100 according to some embodiments of the present application. The battery 100 includes a case 30 and a battery cell 10, and the battery cell 10 is accommodated in the case 30. The case 30 is used to provide an accommodating space for the battery cell 10, and the case 30 may have various structures. In some embodiments, the case 30 may include an upper case 31 and a lower case 32, the upper case 31 and the lower case 32 being covered with each other, the upper case 31 and the lower case 32 together defining an accommodating space for accommodating the battery cell 10. The lower case 32 may have a hollow structure with one end opened, the upper case 31 may have a plate-shaped structure, and the upper case 31 covers the opening side of the lower case 32, so that the upper case 31 and the lower case 32 define an accommodating space together; the upper case 31 and the lower case 32 may be hollow structures each having an opening at one side, and the opening side of the upper case 31 may be closed to the opening side of the lower case 32. Of course, the case 30 formed by the upper case 31 and the lower case 32 may be of various shapes, such as a cylinder, a rectangular parallelepiped, etc.

In the battery 100, the number of the battery cells 10 may be plural, and the plural battery cells 10 may be connected in series, parallel, or series-parallel, and series-parallel refers to both of the plural battery cells 10 being connected in series and parallel. The plurality of battery cells 10 can be directly connected in series or in parallel or in series-parallel, and then the whole formed by the plurality of battery cells 10 is accommodated in the box 30; of course, the battery 100 may also be a battery module formed by connecting a plurality of battery cells 10 in series or parallel or series-parallel connection, and a plurality of battery modules are then connected in series or parallel or series-parallel connection to form a whole and are accommodated in the case 30. The battery 100 may further include other structures, for example, the battery 100 may further include a bus member for making electrical connection between the plurality of battery cells 10.

Wherein each battery cell 10 may be a secondary battery cell or a primary battery cell; but not limited to, lithium sulfur battery cells, sodium ion battery cells, or magnesium ion battery cells. The battery cell 10 may be in the shape of a cylinder, a flat body, a rectangular parallelepiped, or other shapes, etc.

Referring to fig. 3, fig. 3 is an exploded perspective view of a battery cell 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 120 and an end cap 121, the case 120 having an opening, the electrode assembly 11 being disposed inside the case 120, the end cap 121 being connected with the case 120 to close the opening such that the electrode assembly 11 is located in the closed space. In some embodiments, the end cap 121 may be provided with a liquid injection hole from which electrolyte may be injected into the case. In some embodiments, the end cap 121 may be riveted, welded, glued, or threaded to the housing 120.

In some embodiments, the housing 12 is dependent on the shape of the one or more electrode assemblies 11 (i.e., in some embodiments of the present application, the number of electrode assemblies in the battery cell may be one or more), for example, the housing 12 may be a hollow cuboid or a hollow cube or a hollow cylinder. In some embodiments of the present application, the housing 12 may be made of a metallic material, such as aluminum or an aluminum alloy. The housing 12 may also be made of plastic. In some embodiments, the electrode terminal 13 is provided on the case 12, and the electrode terminal 13 is connected with the tab 111 of the electrode assembly 11 to achieve output and input of electric power. 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 disposed on the same wall portion of the housing to connect the electrode tabs 111 with respective corresponding polarities, for example, the electrode terminals with opposite polarities are all disposed on the end cap 121; for another example, electrode terminals having opposite polarities are provided at different wall portions of the housing to be connected to the respective electrode tabs 111 having corresponding polarities, for example, one electrode terminal having one polarity is provided at the end cap 121 and the other electrode terminal having the other polarity is provided at the bottom wall of the case 120. In some embodiments, the electrode terminal 13 is connected to the tab 111 through the adapter 14.

The electrode assembly 11 is composed of a positive electrode sheet and a negative electrode sheet, which are opposite in polarity, and an isolating film disposed between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer, the positive electrode active material layer is coated on the surface of the positive electrode current collector, the positive electrode current collector without the positive electrode active material layer protrudes from the positive electrode current collector coated with the positive electrode active material layer, the positive electrode current collector without the positive electrode active material layer serves as a positive electrode tab, and the positive electrode sheet is connected with a corresponding electrode terminal. In some embodiments, the material of the positive electrode current collector may include aluminum or other metals. The negative electrode sheet comprises a negative electrode current collector and a negative electrode active material layer, wherein 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 out of the negative electrode current collector coated with the negative electrode active material layer, the negative electrode current collector without the negative electrode active material layer is used as a negative electrode lug, and the negative electrode lug is connected with a corresponding electrode terminal. In some embodiments, the material of the negative current collector may include copper or other metals.

According to some embodiments of the application, a pole piece is provided, wherein the pole piece can be a positive pole piece or a negative pole piece. Referring to fig. 4, fig. 4 is a schematic view of a pole piece according to some embodiments of the application.

The pole piece 400 includes a composite current collector 40 and a first active material layer 50. The composite current collector 40 includes a current collector body 41 and a connection part 42 connected to each other along a first direction x, which is perpendicular to a thickness direction of the current collector body 41. In the first direction x, the connection part 42 has a cut-off surface 420 facing away from the current collector body 41, in the thickness direction y of the composite current collector, the current collector body 41 has a first surface 410, the connection part 42 has a second surface 421, the first surface 410 and the second surface 421 are arranged on the same side and are connected to each other, and the first surface 410 and the second surface 421 together form the first coating region 43. The first active material layer 50 is disposed in the first coating region 43.

The composite current collector 40 includes a current collector body 41 and a connection part 42. In some embodiments, the current collector body 41 is the primary component of the composite current collector 40, and the roles of the current collector body 41 include achieving current collection and conduction, and carrying the first active material layer 50. In some embodiments, the current collector body 41 may be a metal foil, and for example, when the electrode sheet 400 is a positive electrode sheet, the current collector body 41 may be aluminum or other metal material, and when the electrode sheet 400 is a negative electrode sheet, the current collector body 41 may be copper or other metal material. In other embodiments, the current collector body 41 may be a multi-layered structure, and the current collector body 41 may include aluminum, a polymer layer 413, and a multi-layered structure of aluminum, by way of example, the electrode sheet 400 is a positive electrode sheet. The electrode sheet 400 is a negative electrode sheet, and the current collector body 41 includes a multilayer structure of copper, a polymer layer 413, and copper.

In some embodiments, the connection portion 42 is a non-metallic material, the connection portion 42 is interconnected with the current collector body 41, and the function of the connection portion 42 includes carrying the first active material layer 50 in conjunction with the current collector body 41. In some embodiments, the surfaces of the current collector body 41 and the connection part 42 on the same side together bear an active material layer in the thickness direction y of the composite current collector. For example, one side of the composite current collector 40 is provided with an active material layer, and for example, both sides of the composite current collector 40 are provided with active material layers.

Illustratively, in the thickness direction y of the composite current collector, the current collector body 41 has a first surface 410, the connection part 42 has a second surface 421, the first surface 410 and the second surface 421 are disposed on the same side and are connected to each other, the first surface 410 and the second surface 421 together form a first coating region 43, in the thickness direction y of the composite current collector, the current collector body 41 has a third surface 411, the third surface 411 and the first surface 410 are opposite to each other, the connection part 42 has a fourth surface 422, the fourth surface 422 and the second surface 421 are opposite to each other, the third surface 411 and the fourth surface 422 are disposed on the same side and are connected to each other, the third surface 411 and the fourth surface 422 together form a second coating region, the active material is coated on the first coating region 43 after being dried to form the first active material layer 50, and the active material is coated on the second coating region after being dried to form the second active material layer 60.

In some embodiments, the connection 42 may have some electrical conductivity such that the connection 42 has the effect of sinking and conducting electrical current.

In some embodiments, the connection portion 42 is connected to the current collector body 41 by bonding, heat fusing, clamping, or the like.

By "the connecting portion 42 has a slit surface 420 facing away from the current collector body 41 in the first direction x" it is understood that when the pole piece material tape 80 is slit, the slit portion falls to correspond to the connecting portion 42 such that the side of the connecting portion 42 facing away from the current collector body 41 is the slit surface 420. The parting plane 420 may be a plane generated by parting in the parting process, for example, the composite current collector belt includes two current collector bodies 41 and a connecting portion 42 connecting the two current collector bodies 41, the parting knife directly falls on the connecting portion 42 to divide the connecting portion 42 into two parts to form two connecting portions 42, one connecting portion 42 is connected with one of the current collector bodies 41 to form one composite current collector 40, a plane of the connecting portion 42 of the composite current collector 40 facing away from the current collector body is the parting plane 420, the other connecting portion 42 is connected with the other current collector to form the other composite current collector 40, and a plane of the connecting portion 42 facing away from the current collector body of the composite current collector 40 is the parting plane 420.

In some embodiments, the connection part 42 may be connected with the current collector body 41 by means of heat fusing, for example, in manufacturing the composite current collector 40, at least two current collector bodies 41 are arranged side by side with a space therebetween, the connection part 42 capable of heat fusing is arranged between two adjacent current collector bodies 41 to connect the two adjacent current collector bodies 41, the current collector bodies 41 and the connection part 42 are walked by the action of the walked rollers 72 (see fig. 8), and the two adjacent current collector bodies 41 are connected by heat-pressing of the heated rollers 71 (see fig. 8) such that the connection part 42 is heat fused to form the composite current collector belt. In some embodiments, the composite current collector strip may refer to a structure capable of carrying active materials, and after slitting, the composite current collector is obtained with a size that meets the requirements.

The composite current collector strip then enters a coating process to be coated with an active material, an active material layer is formed on the surface of the composite current collector 40 to form a pole piece strip 80, and then the pole piece strip 80 enters a slitting station, and a slitting cutter head slits along a connecting portion 42 between two adjacent current collector bodies 41 to form at least two pole pieces 400.

In some embodiments, the material of the connection portion 42 may include at least one of polyurethane-based hot melt adhesives, copolyester hot melt adhesives, vinyl acetate copolymers, copolyamides, polyolefins, or acrylic acid acetate copolymers.

In some embodiments, the material of the connection portion 42 may include a polymer having conductivity, such as polyaniline, polycarbazole, or the like.

In some embodiments, the second surface 421 of the connecting portion 42 may be a concave-convex surface, so as to increase the area carrying the first active material layer 50, thereby effectively improving the connection stability between the connecting portion 42 and the first active material layer 50.

In the above scheme, under the effect that the current collector body 41 can realize the collection and conduction of current, through setting up connecting portion 42 and current collector body 41 and bear first active material layer 50 jointly, in the slitting process of the manufacturing process of battery, the cutter can act on connecting portion 42 in order to form slitting face 420, does not cut to the current collector body 41 of metal material, so can fundamentally avoid the problem of cutting metal particle and burr that produces to effectively reduce metal particle or burr and impale the barrier film and lead to the risk of battery monomer internal short circuit, and then make the reliability of battery high.

In some embodiments, lower cost connections 42 may be utilized, for example, the material of the connections 42 may include a polymer, which may include at least one of polyurethane-based hot melt adhesives, copolyester hot melt adhesives, vinyl acetate copolymers, copolyamides, polyolefins, or acrylic acid copolymers, reducing the material cost of the pole piece 400, reducing the cost of the battery cells, and thus the cost of the battery. In some embodiments, with the less dense connection portion 42, for example, the material of the connection portion 42 may include a polymer, which may include at least one of a polyurethane-based hot melt adhesive, a copolyester-based hot melt adhesive, a vinyl acetate copolymer, a copolyamide, a polyolefin, or an acrylic acid copolymer, the quality of the battery can be effectively reduced, so that the mass density of the battery cell is high, and thus the mass density of the battery is high.

According to some embodiments of the present application, the current collector body 41 has a third surface 411 in a thickness direction y of the composite current collector, the third surface 411 and the first surface 410 are opposite to each other, the connection part 42 includes a first connection piece 423 (see fig. 5) and a connection body 424 (see fig. 5) connected to each other, the connection body 424 is connected to an end surface of the current collector body 41 in a first direction x, the connection body 424 is disposed side by side with the current collector body 41 in the first direction x, and the first connection piece 423 protrudes from the connection body 424 and is connected to the first surface 410 or the third surface 411.

The current collector body 41 has a first surface 410 and a third surface 411 opposite to each other in the thickness direction y of the composite current collector; the connection part 42 includes the first connection piece 423 and the connection body 424 connected to each other in the thickness direction y of the composite current collector. The first connecting portion 42 is disposed corresponding to the first surface 410, and the first connecting member 423 is connected to the first surface 410. Or the first connecting portion 42 is disposed corresponding to the third surface 411, and the first connecting member 423 is connected to the third surface 411.

The connection body 424 is located at a side of the current collector body 41 in the first direction x, and the connection body 424 is connected to an end surface of the current collector body 41 in the first direction x.

In some embodiments, the first connection piece 423 and the orthographic projection portion of the current collector body 41 overlap in the thickness direction y of the composite current collector.

Illustratively, in manufacturing the composite current collector 40, at least two current collector bodies 41 are disposed side by side at intervals, a connection part 42 capable of being thermally fused is disposed between the adjacent two current collector bodies 41, and the number of the connection parts 42 may be one, and one connection part 42 may be located at one side of the current collector body 41 and overlap the first surface 410 or the third surface 411 of the current collector body 41. The current collector body 41 and the connection part 42 are fed by the feeding roller 72, and the connection part 42 located on the first surface 410 or the third surface 411 is hot-melted by the hot pressing of the hot roller 71 to connect the adjacent two current collector bodies 41, and at the same time, a portion of the connection part 42, which is changed in shape by the hot melting, fills the gap between the two current collector bodies 41, and a portion thereof overlaps the surface of the current collector body 41. In the subsequent slitting process, the portion of the connection portion 42 located in the gap is slit into the connection body 424, and the portion overlapping the surface of the current collector body 41 is slit into the first connection piece 423.

In some embodiments, the heat roller 71 may correspond to one of the tape rollers 72, and the current collector body 41 and the connection part 42 may be rolled on the tape roller 72 by the heat roller 71.

Referring to fig. 5, fig. 5 is a schematic diagram of a composite current collector 40 according to some embodiments of the present application.

The connection portion 42 further includes a second connection member 425, the second connection member 425 being connected to the connection body 424.

Along the first direction x, the first connecting member 423 protrudes from the connecting body 424 and is connected to the first surface 410, and the second connecting member 425 protrudes from the connecting body 424 and is connected to the third surface 411.

The current collector body 41 has a first surface 410 and a third surface 411 opposite to each other in the thickness direction y of the composite current collector; along the thickness direction y of the composite current collector, the connection part 42 includes a first connection member 423, a connection body 424, and a second connection member 425 connected to each other, the first connection member 42 is disposed corresponding to the first surface 410, the first connection member 423 is connected to the first surface 410, the second connection member 425 is disposed corresponding to the third surface 411, the second connection member 425 is connected to the third surface 411, the connection body 424 is located at a side of the current collector body 41 along the first direction x, and the connection body 424 is connected to an end surface of the current collector body 41 along the first direction x.

In some embodiments, the first connection member 423, the second connection member 425, and the orthographic projection portion of the current collector body 41 overlap in the thickness direction y of the composite current collector.

Illustratively, in manufacturing the composite current collector 40, at least two current collector bodies 41 are arranged side by side at intervals, a thermally fusible connecting portion 42 is arranged between two adjacent current collector bodies 41, the number of the connecting portions 42 is two, and the two connecting portions 42 are respectively located at two sides of the current collector body 41 and respectively overlap the surfaces of the current collector bodies 41; the current collector body 41 and the connection part 42 are fed by the feeding roller 72, and the connection parts 42 on both sides are hot-melted by the hot pressing of the hot roller 71 to connect the adjacent two current collector bodies 41, and at the same time, the portions of the two connection parts 42, which are changed in shape by the hot melting, are filled into the gap between the two current collector bodies 41, and the portions are overlapped on the surface of the current collector body 41. In the subsequent slitting process, the portion of the connection portion 42 located in the gap is slit into the connection body 424, and the portion overlapped on the surface of the current collector body 41 is slit into the first connection member 423 and the second connection member 425.

In the above-mentioned scheme, through setting up convex first connecting piece 423 and second connecting piece 425, can make the relation of connection between connecting portion 42 and the mass flow body 41 stable to make first active material layer 50 stably set up on compound current collector 40, reduce the risk that first active material layer 50 breaks away from in compound current collector 40, make the single reliability of battery high, and then make the reliability of battery high.

In some embodiments, the connection portion 42 includes a first connection piece 423 and a connection body 424 connected to each other, the first connection piece 423 being connected to the first surface 410. In other embodiments, the connecting portion 42 includes a second connecting member 425 and a connecting body 424 that are connected to each other, the second connecting member 425 being connected to the third surface 411. In other embodiments, the connection 42 includes a connection body 424.

According to some embodiments of the application, the first active material layer 50 has a first side 51 along the first direction x, the first side 51 being disposed on the same side as the split surface 420. The first side 51 is coplanar with the split surface 420, or the split surface 420 protrudes from the plane of the first side 51 along the first direction x.

The first side 51 is a side of the first active material layer 50 in the first direction x, and the first side 51 is disposed on the same side as the slit surface 420. In some embodiments, referring to fig. 4, when the first side 51 and the dividing plane 420 are coplanar, it may be understood that when dividing the pole piece material strip 80, the dividing head divides the pole piece material strip 80 along the thickness direction y of the composite current collector, and the dividing position corresponds to the connection portion 42, and acts on the first active material layer 50 and the connection portion 42 when dividing, so as to form the first side 51 and the dividing plane 420 at the same time. In other embodiments, in the first direction x, the dividing plane 420 protrudes from the plane of the first side 51, i.e. the first active material layer 50 does not cover the surface of the connection portion 42 completely, and there is a region where the first active material layer 50 is not disposed, i.e. the active material layer is not acted upon during dividing.

In the above solution, in some embodiments, the first side 51 and the dividing plane 420 are arranged coplanar, so that the amount of the first active material layer 50 on the composite current collector 40 can be increased, which is beneficial to improving the volume and the mass energy density of the battery. In other embodiments, the dividing surface 420 is beyond the plane of the first side 51, so that the connecting portion 42 provides a larger supporting surface for the first active material layer 50, which reduces the risk of the active material layer separating from the composite current collector 40, so that the battery cell has higher reliability, and the reliability of the battery is higher.

According to some embodiments of the present application, referring to fig. 4, in a first direction x, the first surface 410 includes a first empty foil region 4100 and a first connection region 4101 connected to each other, the first connection region 4101 is closer to the second surface 421 than the first empty foil region 4100, and the first connection region 4101 and the second surface 421 together form a first coating region 43.

The first empty foil region 4100 is a region of the first surface 410 that is not coated with active material, and the first connection region 4101 is a region of the first surface 410 that is coated with active material. In the first direction x, the first blank foil is in a region of the first connection region 4101 facing away from the second surface 421.

In some embodiments, the first blank foil region 4100 may be die cut with a die cutting process, or the first blank foil region 4100 may be attached to the tab by welding, riveting, or the like.

In the above scheme, the first empty foil region 4100 is provided to facilitate the output and input of current.

Referring to fig. 4, according to some embodiments of the present application, the pole piece 400 further includes a second active material layer 60. Along the thickness direction y of the composite current collector, the current collector body 41 has a third surface 411, the third surface 411 and the first surface 410 are opposite to each other, the connection part 42 has a fourth surface 422, the fourth surface 422 and the second surface 421 are opposite to each other, the third surface 411 and the fourth surface 422 are disposed on the same side and are connected to each other, the third surface 411 and the fourth surface 422 together form a second coating region, and the second active material layer 60 is disposed in the second coating region.

The second active material layer 60 has an active structure provided on the surface of the composite current collector 40. In some embodiments, the second active material layer 60 is disposed opposite the first active material layer 50 along the thickness direction y of the composite current collector, on opposite sides of the composite current collector 40 from each other, respectively.

A portion of the second active material layer 60 is carried by the third surface 411 of the current collector body 41, and another portion of the second active material layer 60 is carried by the fourth surface 422 of the connection portion 42.

In some embodiments, the fourth surface 422 of the connection portion 42 may be a concave-convex surface, so as to increase the area carrying the second active material layer 60, thereby effectively improving the connection stability between the connection portion 42 and the second active material layer 60.

In the above scheme, the second active material layer 60 is disposed, so that the two sides of the composite current collector 40 are respectively provided with the active material layers, which is favorable for improving the capacitance of the battery cell, so that the battery cell has higher volumetric energy density, and further the battery has higher volumetric energy density.

According to some embodiments of the present application, the projections of the first active material layer 50 and the second active material layer 60 coincide with each other in the thickness direction y of the composite current collector.

In some embodiments, with the end of the current collector body 41 facing away from the connection portion 42 being the empty foil end, the distance of the first active material layer 50 from the empty foil end and the distance of the second active material layer 60 from the empty foil end may be equal.

In some embodiments, in the pole piece material strip 80, the active material may cover the connection portion 42 between the two current collector bodies 41, and the first active material layer 50 and the second active material layer 60 on the surface may be used to determine the splitting position during splitting, so that the splitting area is the area where the connection portion 42 is located.

In the above-mentioned scheme, by setting the projections of the first active material layer 50 and the second active material layer 60 to be mutually overlapped, on one hand, in the process of slitting the pole piece 400, no matter the first active material layer 50 or the second active material layer 60 is used for obtaining the reference point for judging the slitting position, the slitting position can be effectively and accurately found, so that the slitting efficiency is improved, the risk that metal particles and burrs are generated when the cutter cuts the current collector body 41 due to slitting deviation is reduced, the reliability of the battery cell is high, and the reliability of the battery is high; on the other hand, the uniformity of the active material of the electrode sheet 400 can be improved, which is advantageous for improving the conductivity and improving the charge and discharge performance of the battery.

According to some embodiments of the present application, referring to fig. 4, the dimension of the connection portion 42 is not less than 0.5mm and not more than 5mm along the first direction x.

In fig. 4, the dimension of the connecting portion 42 in the first direction x is denoted as a, and may have a value of 0.5mm, 0.6mm, 0.7mm, 0.8mm …, 4.7mm, 4.8mm, 4.9mm, 5.0mm, or any value between adjacent two values.

In the above scheme, the dimension of the connecting portion 42 in the first direction x is set to be not smaller than 0.5mm, so that the connecting portion 42 can provide a larger supporting area for the active material layer, the risk that the first active material layer 50 is separated from the composite current collector 40 is reduced, the probability that the cutter cuts the current collector body 41 is reduced, the cutting quality is improved, the problem of metal particles and burrs generated by cutting can be fundamentally avoided, the risk that the metal particles or burrs pierce the isolating film to cause internal short circuit of the battery is effectively reduced, and the reliability of the battery is further high; by setting the dimension of the connecting portion 42 in the first direction x to be not more than 5mm, it is possible to reduce the risk that the connecting portion 42 occupies too much space of the current collector body 41, resulting in reduced conductivity of the composite current collector 40; for this reason, by setting the dimension of the connecting portion 42 in the first direction x to not less than 0.5 and not more than 5mm, the supporting effect on the active material layer, the slitting quality, and the conductivity of the composite current collector 40 can be simultaneously achieved.

According to some embodiments of the present application, the material of the current collector body 41 includes copper or aluminum.

In some embodiments, the current collector body 41 may be copper foil or aluminum foil. In other embodiments, the current collector body 41 may be other metal foils, or a multilayer structure of metal foils plus a polymer layer 413.

Referring to fig. 6, fig. 6 is a schematic diagram of a pole piece 400 according to another embodiment of the present application.

The current collector body 41 includes a metal conductive layer 412, or the current collector body 41 includes a metal conductive layer 412 and a polymer layer 413, and the polymer layer 413 is interposed between the two metal conductive layers 412 in the thickness direction y of the composite current collector.

In some embodiments, the current collector body 41 of the electrode tab 400 may be a multi-layered structure, such as a multi-layered structure of the metal conductive layer 412, the polymer layer 413, and the metal conductive layer 412. The metal conductive layer 412 may be a metal foil, such as aluminum foil or copper foil. In some embodiments, portions of the connection 42 may be connected to the polymer layer 413 and the remaining portions may be connected to the metal conductive layer 412. The active material may be coated on the connection portion 42 and the metal conductive layer 412, for example, the first active material layer 50 may be coated on the surface of the connection portion 42 and the surface of the metal conductive layer 412, and the second active material layer 60 may be coated on the surface of the connection portion 42 and the surface of the other metal conductive layer 412.

In the above-mentioned scheme, by providing the polymer layer 413, on one hand, the density of the current collector body 41 can be reduced, so that the mass density of the battery cell is improved, and the mass density of the battery is further improved; on the other hand, the material cost of the current collector body 41 can be effectively reduced, and the manufacturing cost of the battery is reduced; on the other hand, the polymer layer 413 can generate breaking efficiency when the battery is punctured, so that the reliability of the battery can be effectively improved; on the other hand, when the connection portion 42 is a hot-melt material, the polymer layer 413 has a good connection effect with the connection portion 42, so that the combination between the current collector body 41 and the connection portion 42 is stable, and is not easily broken, so that the battery has high reliability.

According to some embodiments of the present application, the material of the connection part 42 includes a hot melt adhesive, and the connection part 42 is connected to the current collector body 41 by hot pressing.

In some embodiments, when manufacturing the composite current collector 40, the raw material forming the connection part 42 may be a hot melt adhesive, which is disposed between the two current collector bodies 41 in the state of the adhesive tape 70, and the adhesive tape 70 is melted by hot pressing, thereby connecting the two current collector bodies 41.

In the above-described aspect, by setting the material of the connection portion 42 to include the hot melt adhesive, the connection portion 42 can be made to form a stable connection relationship with the current collector body 41 under the action of the hot press.

In other embodiments, the material of the connection portion 42 may include a polymer and an adhesive layer, where the polymer is the body of the connection portion 42, and the polymer is adhered to the current collector body 41 through the adhesive layer.

According to some embodiments of the present application, the material of the connecting portion 42 includes at least one of polyurethane hot melt adhesive, copolyester hot melt adhesive, vinyl acetate copolymer, copolyamide, polyolefin or acrylic acid acetate copolymer.

Some embodiments of the present application also provide a battery cell, referring to fig. 3, the battery cell 10 includes an electrode assembly 11, the electrode assembly 11 including a positive electrode sheet and a negative electrode sheet, at least one of the positive and negative electrode sheets being the electrode sheet 400 provided above.

In some embodiments, the positive electrode sheet and the negative electrode sheet may be the electrode sheet 400 provided above, that is, the portions of the positive electrode sheet material strip that are cut are the connection portions 42 instead of the positive electrode current collector body of the metal material when the positive electrode sheet material strip is cut, and the portions of the negative electrode sheet material strip that are cut are the connection portions 42 instead of the negative electrode current collector body of the metal material when the negative electrode sheet material strip is cut.

In some embodiments, the positive electrode sheet may be the sheet 400 provided above. In other embodiments, the negative electrode sheet may be the sheet 400 provided above.

The battery cell 10 also includes a housing 12. The case 12 includes a case 120 and an end cap 121, the case 120 having an opening, the electrode assembly 11 being disposed inside the case, the end cap 121 being connected with the case 120 to close the opening such that the electrode assembly 11 is located in the closed space. In some embodiments, the end cap 121 may be provided with a liquid injection hole from which electrolyte may be injected into the case. In some embodiments, the end cap may be riveted, welded, glued, or threaded to the housing.

In the above-mentioned scheme, because the pole piece 400 in the battery monomer 10 bears the active material layer together through setting up connecting portion 42 and current collector body 41, on the one hand, in the slitting process of the manufacturing process of battery, the cutter can act on connecting portion 42 in order to form the slitting face 420, the current collector body 41 of metal material is not cut, so can fundamentally avoid the problem of cutting metal particle and burr that produces, thereby effectively reduce metal particle or burr and impale the risk that the barrier film leads to the battery monomer internal short circuit, and then make the reliability of battery high. On the other hand, the connecting part 42 with lower cost can be utilized, so that the material cost of the pole piece 400 is reduced, the cost of the battery monomer is reduced, and the cost of the battery is further reduced; on the other hand, the connection portion 42 having a smaller density can effectively reduce the mass of the battery, so that the mass density of the battery cell is high, and thus the mass density of the battery is high.

Some embodiments of the present application also provide a battery, please refer to fig. 2, which includes the battery cells provided above.

The battery 100 includes a case 30 and a battery cell 10, and the battery cell 10 is accommodated in the case 30. The case 30 is used to provide an accommodating space for the battery cell 10, and the case 30 may have various structures. In some embodiments, the case 30 may include an upper case 31 and a lower case 32, the upper case 31 and the lower case 32 being covered with each other, the upper case 31 and the lower case 32 together defining an accommodating space for accommodating the battery cell 10. The lower case 32 may have a hollow structure with one end opened, the upper case 31 may have a plate-shaped structure, and the upper case 31 covers the opening side of the lower case 32, so that the upper case 31 and the lower case 32 define an accommodating space together; the upper case 31 and the lower case 32 may be hollow structures each having an opening at one side, and the opening side of the upper case 31 may be closed to the opening side of the lower case 32. Of course, the case 30 formed by the upper case 31 and the lower case 32 may be of various shapes, such as a cylinder, a rectangular parallelepiped, etc.

According to some embodiments of the application there is also provided an electrical device comprising the battery cell provided above, the battery cell being for providing electrical energy.

In some embodiments, the power device may include a vehicle, which may be a fuel-oil vehicle, a gas-oil vehicle, or a new energy vehicle, which may be a pure electric vehicle, a hybrid vehicle, or an extended range vehicle, etc. The interior of the vehicle is provided with a battery cell, which may be provided at the bottom or the head or the tail of the vehicle. The battery cell may be used for power supply of a vehicle.

Referring to fig. 7, fig. 7 is a flow chart of a method for manufacturing a pole piece 400 according to some embodiments of the present application.

The manufacturing method of the pole piece comprises the following steps:

s1, providing a composite current collector 40, wherein at least two current collector bodies 41 are arranged at intervals along a first direction x and form a gap penetrating along a second direction, a connecting part 42 is arranged in the gap, two adjacent current collector bodies 41 are connected through the connecting part 42 to form the composite current collector 40, the first direction x is perpendicular to the thickness direction of the current collector bodies 41, and the second direction is parallel to the thickness direction of the current collector bodies 41;

s2, coating active substances on the surface of the current collector body 41 and the surface of the connecting part 42 along the thickness direction y of the composite current collector to obtain a pole piece material belt 80;

s3, cutting the pole piece material belt 80 along the second direction corresponding to the connecting part 42 to obtain at least two pole pieces 400.

The second direction may be parallel to the thickness direction y of the composite current collector. In step S1, the current collector body 41 and the connection portion 42 are provided, and the connection portion 42 may be a hot melt adhesive in the state of an adhesive tape, hereinafter referred to as an adhesive tape 70. The current collector body 41 and the adhesive tape 70 are carried in a tape state. The two current collector bodies 41 are discharged by the tape feed roller 72, and the tape feed direction may be a third direction z, which is perpendicular to each other, a second direction z, and a first direction x. The two current collector bodies 41 are spaced apart in the first direction x and form a through-gap in the second direction. In some embodiments, please refer to fig. 8 and 9, fig. 8 is a schematic diagram of a manufacturing process of the composite current collector 40 according to some embodiments of the present application, and fig. 9 is a schematic diagram of two current collector bodies 41 and an adhesive tape 70 according to some embodiments of the present application. The adhesive tape 70 is disposed at a side (e.g., upper side) of the current collector body 41, and the adhesive tape 70 is carried around and disposed on the surfaces of the two current collector bodies 41 to close the gap. In other embodiments, please refer to fig. 10 and 11, wherein fig. 10 is a schematic diagram illustrating a manufacturing process of the composite current collector 40 according to other embodiments of the present application, and fig. 11 is a schematic diagram illustrating two current collector bodies 41 and two adhesive tapes 70 according to other embodiments of the present application. Adhesive tapes 70 are respectively provided at both sides of the current collector body 41 opposite to each other, for example, the upper and lower sides of the current collector body 41 are respectively provided with the adhesive tapes 70, the two adhesive tapes 70 are carried, and are provided at the surfaces of the two current collector bodies 41 opposite to each other and jointly close the gap.

Referring to fig. 12, fig. 12 is a schematic diagram of a composite current collector 40 according to some embodiments of the present application, hot-pressing the hot roller 71 is utilized to make the adhesive tape 70 be hot-melted in the gap and connect the two current collector bodies 41, the adhesive tape 70 is cooled to form the connecting portion 42, thereby forming a composite current collector material tape, and then the coating process is performed, i.e. step S2 is performed.

In step S2, please refer to fig. 13, fig. 13 is a schematic diagram of a pole piece strip 80 according to some embodiments of the present application. The active material is coated on the surface of the current collector body 41 and the surface of the connection part 42 to form an active material layer, thereby obtaining the electrode sheet material tape 80. In step S2, active material layers may be coated on both sides of the current collector body 41 and the connection part 42, respectively, to obtain the first active material layer 50 and the second active material layer 60, respectively.

In step S3, please refer to fig. 14, fig. 14 is a schematic diagram of the pole piece material strip 80 after being cut in accordance with some embodiments of the present application. The pole piece material strip 80 obtained in step S2 is slit, and the slit position corresponds to the connecting portion 42, so that the cutter cuts the pole piece material strip 80 along the connecting portion 42 in the second direction to slit the pole piece material strip 80 into two pole pieces 400.

In the above scheme, the connecting portion 42 is disposed between two adjacent collector bodies 41 to form the composite collector 40, so that on one hand, when the pole piece material strip 80 is cut, the cutter bit can fall on the position where the connecting portion 42 is located, and the collector body 41 is not cut, thereby fundamentally avoiding the problems of metal particles and burrs generated by cutting, effectively reducing the risk of internal short circuit of the battery cell caused by the penetration of the isolating film by the metal particles or burrs, and further improving the reliability of the battery; on the other hand, the active material can be coated on the current collector body 41 and the connecting part 42 with lower cost and density, and supported by the current collector body 41 and the connecting part 42 together, so that the material cost of the pole piece 400 can be reduced, the cost of the battery cell can be further reduced, the quality of the battery cell can be effectively reduced, the quality density of the battery cell is high, and the quality density of the battery cell is further high.

According to some embodiments of the present application, the material of the connecting portion 42 includes a hot melt adhesive. In step S1, providing the composite current collector 40 includes:

the hot melt adhesive is located between the adjacent two current collector bodies 41 and overlapped on the surfaces of the adjacent two current collector bodies 41 in the thickness direction y of the composite current collector, and the hot melt adhesive is hot-pressed so that the hot melt adhesive melts and enters the gap to form the connection part 42.

For example, please refer to fig. 8. In some embodiments, the hot melt adhesive is provided to the current collector body 41 in the state of the adhesive tape 70. A hot melt adhesive is provided at one side of the current collector bodies 41, and the hot melt adhesive is provided at the surfaces of the two current collector bodies 41 and closes the gap. Or two hot melt adhesives are respectively provided at both sides of the current collector body 41 opposite to each other, for example, the upper side and the lower side of the current collector body 41 are respectively provided with the hot melt adhesives, the two hot melt adhesives are carried by, and are provided at the surfaces of the two current collector bodies 41 opposite to each other and jointly close the gap.

The hot melt adhesive is hot pressed, and the hot pressing temperature can be adjusted according to the specific material of the hot melt adhesive, for example, the hot pressing temperature can be 80-250 ℃. During the running of the hot melt adhesive and the current collector body 41, hot pressing may be performed by the hot roller 71. The hot pressing may include reducing the height of the hot melt adhesive beyond the surface of the current collector body 41 to avoid rolling bulges; filling the hot melt adhesive into the gap between the two current collector bodies 41; by compressing the hot melt adhesive, the thickness of the active material coated on the surface of the hot melt adhesive can be increased, which is beneficial to improving the energy density of the battery.

In some embodiments, when the hot melt adhesive is disposed on only one side of the current collector body 41, the thickness of the hot melt adhesive before hot pressing is not greater than the thickness of the current collector body 41.

In the above-described aspect, by setting the material of the connection portion 42 to include the hot melt adhesive, the connection portion 42 can be efficiently formed between the adjacent two current collector bodies 41 through a simple hot pressing process, thereby making the manufacturing efficiency of the composite current collector 40 high.

According to some embodiments of the present application, referring to fig. 10, in step S1, providing a composite current collector 40, includes:

Along the thickness direction y of the composite current collector, two sides of the adjacent two current collector bodies 41 opposite to each other are respectively provided with a hot melt adhesive.

For example, please refer to fig. 8-12. In some embodiments, the hot melt adhesive is provided to the current collector body 41 in the state of the adhesive tape 70. Two hot melt adhesives are respectively provided at both sides of the current collector body 41 opposite to each other, for example, the upper side and the lower side of the current collector body 41 are respectively provided with hot melt adhesives, the two hot melt adhesives are carried along, and are provided at the surfaces of the two current collector bodies 41 opposite to each other and jointly close the gap. The hot melt adhesive is hot pressed, and the hot pressing temperature can be adjusted according to the specific material of the hot melt adhesive, for example, the hot pressing temperature can be 80-250 ℃. During the running of the hot melt adhesive and the current collector body 41, hot pressing may be performed by the hot roller 71.

In some embodiments, when hot melt adhesives are disposed on both sides of the current collector body 41, respectively, the sum of the thicknesses of the two hot melt adhesives before hot pressing is not greater than the thickness of the current collector body 41.

In the above-mentioned scheme, through being provided with the hot melt adhesive respectively in the both sides that are opposite each other of two adjacent collector bodies 41, can make the hot melt adhesive when melting, get into the clearance between two adjacent collector bodies 41 evenly by two opposite each other's of two adjacent collector bodies 41, on the one hand, make between two adjacent collector bodies 41 and the connecting portion 42 structural relationship stable, on the other hand, make the hot melt adhesive melt the partial connecting portion 42 thickness that forms that adheres to collector body 41 surface even, thereby make the active material layer set up on the surface of collector body 41 and connecting portion 42 steadily.

According to some embodiments of the present application, in step S1, providing a composite current collector 40 includes:

the hot melt adhesive has a center line parallel to the second direction, and the center lines of two hot melt adhesives located at opposite sides of the adjacent two current collector bodies 41 from each other are not more than 0.5mm apart in the first direction x.

In some embodiments, the hot melt adhesive has a centerline parallel to the second direction that divides the hot melt adhesive into two equal area regions along the first direction x. Referring to fig. 11, the centerlines of the two hot melt adhesives are designated by the reference numerals B and C in fig. 11, respectively.

In some embodiments, the hot melt adhesive on the upper side of the current collector body 41 is a first hot melt adhesive, the center line of which is denoted by B, the hot melt adhesive on the lower side of the current collector body 41 is a second hot melt adhesive, the center line of which is denoted by C, and the distance between the center line B of the first hot melt adhesive and the center line C of the second hot melt adhesive may be 0, 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm or any value between adjacent two values along the first direction x.

In some embodiments, to provide good connection stability between the adjacent two current collector bodies 41 and the hot melt adhesive, the center line of the hot melt adhesive may be disposed corresponding to the gap between the adjacent two current collector bodies 41.

In some embodiments, by setting the distances of the center lines of the two hot melt adhesives located at the two sides of the adjacent two current collector bodies 41 opposite to each other in the first direction x to be not more than 0.5mm, the alignment degree between the hot melt adhesives located at the two sides can be made high, so that the hot melt adhesives located at the different two sides can be stably connected to the current collector bodies 41.

In the above-mentioned scheme, by offsetting the center lines of the two hot melt adhesives located at two sides of the current collector body 41 by a distance not greater than 0.5mm, the hot melt adhesives can uniformly enter the gap between the two adjacent current collector bodies 41 from two sides of the two adjacent current collector bodies 41 opposite to each other when melting, so that the surface flatness of the composite current collector 40 is high, and the active substances are beneficial to coating on the surface of the composite current collector 40.

In some embodiments, the material of the connection portion 42 may include at least one of polyurethane hot melt adhesive, copolyester hot melt adhesive, vinyl acetate copolymer, copolyamide, polyolefin or acrylic acid copolymer, so that in step S1, the connection portion 42 is formed between two adjacent current collector bodies 41 by means of hot pressing.

According to some embodiments of the present application, the current collector body 41 includes a metal conductive layer 412, or, the current collector body 41 includes a metal conductive layer 412 and a polymer layer 413, and the polymer layer 413 is interposed between the two metal conductive layers 412 in the thickness direction y of the composite current collector.

In some embodiments, referring to fig. 8-14, the current collector body 41 may be a metal conductive layer 412.

In other embodiments, please refer to fig. 8 and 15, or fig. 10, 16-19, fig. 15 is a schematic diagram of the current collector body 41 and the adhesive tape 70 according to other embodiments of the present application, fig. 16 is a schematic diagram of the current collector body 41 and the adhesive tape 70 according to other embodiments of the present application, fig. 17 is a schematic diagram of the current collector body 41 and the connecting portion 42 according to other embodiments of the present application, fig. 18 is a schematic diagram of the pole piece material strip 80 according to other embodiments of the present application, and fig. 19 is a schematic diagram of the pole piece material strip 80 after being cut according to other embodiments of the present application.

The current collector body 41 may have a multi-layer structure of a metal conductive layer 412 and a polymer layer 413, for example, the polymer layer 413 is sandwiched between two metal conductive layers 412 along the thickness direction y of the composite current collector.

Illustratively, in step S1, the current collector body 41 and the connection part 42 of the multilayer structure are provided, and the connection part 42 may be a hot melt adhesive in the state of an adhesive tape 70, hereinafter referred to as an adhesive tape 70. The current collector body 41 and the adhesive tape 70 are carried in a tape state. The two current collector bodies 41 are discharged by the tape feed roller 72, and the tape feed direction may be a third direction z, which is perpendicular to each other, a second direction z, and a first direction x. The two current collector bodies 41 are spaced apart in the first direction x and form a through-gap in the second direction. In some embodiments, please refer to fig. 8 and 15. The adhesive tape 70 is disposed at a side (e.g., upper side) of the current collector body 41, and the adhesive tape 70 is carried around and disposed on the surfaces of the two current collector bodies 41 to close the gap. In other embodiments, referring to fig. 10 and 16, adhesive tapes 70 are respectively disposed on both sides of the current collector body 41 opposite to each other, for example, the upper and lower sides of the current collector body 41 are respectively provided with the adhesive tapes 70, and the two adhesive tapes 70 are carried and disposed on the surfaces of the two current collector bodies 41 opposite to each other and jointly close the gap.

Referring to fig. 17, the adhesive tape 70 is hot-melted in the gap and connects the two current collector bodies 41 by using the hot-pressing of the hot roller 71, the hot-melted adhesive tape 70 can connect the polymer layer 413 and the metal conductive layer 412, the connection portion 42 is formed after cooling, and the composite current collector material tape is formed, and then the coating process is performed, that is, step S2 is performed.

In step S2, referring to fig. 18, an active material is coated on the surface of the current collector body 41 and the surface of the connection portion 42 to form an active material layer, thereby obtaining a pole piece tape 80. In step S2, active material layers may be coated on both sides of the current collector body 41 and the connection part 42, respectively, to obtain the first active material layer 50 and the second active material layer 60, respectively.

In step S3, referring to fig. 19, the pole piece material strip 80 obtained in step S2 is cut, and the cut portion corresponds to the connection portion 42, so that the cutter cuts the pole piece material strip 80 into two pole pieces 400 along the connection portion 42 in the second direction.

Referring to fig. 7-19, a method for manufacturing a pole piece 400 is provided according to some embodiments of the present application, wherein the method for manufacturing the pole piece 400 includes the following steps:

In step S1, the current collector body 41 may be a metal conductive layer 412, or may be a multi-layer structure of a metal conductive layer 412 and a polymer, for example, a multi-layer structure of a metal conductive layer 412 and a polymer layer 413 and a metal conductive layer 412. The connection 42 may be a hot melt adhesive that is provided (e.g., adhered) to the same side or opposite sides of adjacent two current collectors in the form of an adhesive tape 70.

Illustratively, two current collector bodies 41 are disposed side by side in a first direction x and are each taken along in a third direction z by a take-away roller 72, the take-away direction being parallel to the third direction. The two current collector bodies 41 are disposed at intervals along the first direction x and form a through gap along the second direction, and the dimension of the gap in the first direction x may be not less than 1mm and not more than 10mm (for example, 1mm, 2mm, 3mm, 4mm … mm, 10mm, or any value between adjacent two values). In some embodiments, the dimensions of the two current collector bodies 41 in the first direction x may or may not be equal.

The adhesive tape 70 is provided at one side of the current collector body 41, or the adhesive tapes 70 are provided at the upper and lower sides of the current collector body 41, respectively, and the alignment dislocation of the adhesive tapes 70 at both sides is not more than 0.5mm. The tape 70 is carried along with the surface of the current collector body 41 and closes the gap. By hot pressing of the heat roller 71, the adhesive tape 70 is heat-melted in the gap and connects the two current collector bodies 41, and the connection portion 42 is formed after cooling, thereby forming a composite current collector material tape. The hot pressing temperature may be between 80 degrees celsius and 250 degrees celsius, based on the fact that the specific material of the tape 70 is capable of being hot melted.

In step S2, an active material is coated on the surface of the current collector body 41 and the surface of the connection portion 42 to form an active material layer, thereby obtaining the electrode sheet material tape 80. In step S2, active material layers may be coated on both sides of the current collector body 41 and the connection part 42, respectively, to obtain the first active material layer 50 and the second active material layer 60, respectively. In some embodiments, the composite current collector strip coated with active material may be subjected to a cooling and die cutting process.

In step S3, when the pole piece material strip 80 obtained in step S2 is slit, the cutter is located in the adhesive area of the adhesive tape 70, that is, the area where the connecting portion 42 is located, so that the pole piece material strip 80 is divided into two pieces to form two pole pieces 400, and the cutter does not contact the metal conductive layer 412 of the current collector body 41, so that no slit edge metal particles and burrs are generated.

The above description is only of the preferred embodiments of the present application and is not intended to limit the present application, but various modifications and variations can be made to the present application by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A pole piece, comprising:

A composite current collector including a current collector body and a connection part connected to each other in a first direction, the first direction being perpendicular to a thickness direction of the current collector body, the connection part having a parting plane facing away from the current collector body in the first direction, the current collector body having first and third surfaces facing each other in the thickness direction of the composite current collector, the connection part having a second surface, the first and second surfaces being disposed on the same side and connected to each other, the first and second surfaces together forming a first coating region;

A first active material layer disposed in the first coating region;

The connecting part is made of nonmetallic materials and comprises a first connecting piece and a connecting body which are connected with each other, the connecting body is connected with the end face of the current collector body along the first direction, the connecting body and the current collector body are arranged side by side along the first direction, and the first connecting piece protrudes out of the connecting body and is connected to the first surface or the third surface.

2. A pole piece as claimed in claim 1, wherein,

The connecting part further comprises a second connecting piece, the second connecting piece is connected with the connecting body, the first connecting piece is connected to the first surface, and along the first direction, the second connecting piece protrudes out of the connecting body and is connected to the third surface.

3. A pole piece as claimed in claim 1, wherein,

The first active material layer is provided with a first side surface along the first direction, and the first side surface and the parting surface are arranged on the same side;

the first side surface is coplanar with the cutting surface, or along the first direction, the cutting surface protrudes out of the plane where the first side surface is located.

4. A pole piece as claimed in claim 1, wherein,

Along the first direction, the first surface comprises a first empty foil area and a first connection area connected with each other, the first connection area is closer to the second surface than the first empty foil area, and the first connection area and the second surface jointly form the first coating area.

5. The pole piece of claim 4, wherein the pole piece comprises a plurality of pole pieces,

The pole piece further comprises a second active material layer;

along the thickness direction of compound current collector, the current collector body has the third surface, the third surface with first surface is relative each other, the connecting portion has the fourth surface, the fourth surface with the second surface is relative each other, the third surface with fourth surface homonymy sets up and interconnect, the third surface with the fourth surface jointly forms the second coating district, the second active material layer set up in the second coating district.

6. The pole piece of claim 5, wherein the pole piece comprises a plurality of pole pieces,

And along the thickness direction of the composite current collector, the projections of the first active material layer and the second active material layer are mutually overlapped.

7. A pole piece according to any of the claims 1-6, characterized in that,

The dimension of the connecting portion is not less than 0.5mm and not more than 5mm along the first direction.

8. A pole piece according to any of the claims 1-6, characterized in that,

The material of the current collector body comprises copper or aluminum.

9. A pole piece according to any of the claims 1-6, characterized in that,

The current collector body comprises a metal conductive layer, or comprises a metal conductive layer and a polymer layer, and the polymer layer is clamped between the two metal conductive layers along the thickness direction of the composite current collector.

10. A pole piece according to any of the claims 1-6, characterized in that,

The material of connecting portion includes hot melt adhesive, connecting portion pass through hot pressing with the mass flow body is connected.

11. The pole piece of claim 10, wherein the pole piece is configured to,

The material of the connecting part comprises at least one of polyurethane hot melt adhesive, copolyester hot melt adhesive, vinyl acetate copolymer, copolyamide, polyolefin or acetic acid acrylic acid copolymer.

12. A battery cell comprising an electrode assembly comprising a positive electrode sheet and a negative electrode sheet, at least one of the positive electrode sheet and the negative electrode sheet being the electrode sheet of any one of claims 1-11.

13. A battery comprising the battery cell of claim 12.

14. An electrical device comprising the battery cell of claim 12 for providing electrical energy.

15. The manufacturing method of the pole piece is characterized by comprising the following steps:

providing a composite current collector, wherein at least two current collector bodies are arranged at intervals along a first direction and form a gap penetrating along a second direction, a connecting part is arranged in the gap, two adjacent current collector bodies are connected through the connecting part to form the composite current collector, the first direction is perpendicular to the thickness direction of the current collector bodies, and the second direction is parallel to the thickness direction of the current collector bodies;

and cutting the pole piece material belt along the second direction corresponding to the connecting part to obtain at least two pole pieces.

16. The method of manufacturing a pole piece according to claim 15, wherein,

The material of the connecting part comprises hot melt adhesive;

The provision of a composite current collector includes:

the hot melt adhesive is positioned between two adjacent current collector bodies and is lapped on the surfaces of the two adjacent current collector bodies along the thickness direction of the composite current collector, and the hot melt adhesive is hot-pressed, so that the hot melt adhesive is melted and enters the gap to form the connecting part.

17. The method of manufacturing a pole piece according to claim 16, wherein,

The provision of a composite current collector includes:

And the hot melt adhesives are respectively arranged on two opposite sides of two adjacent current collector bodies along the thickness direction of the composite current collector.

18. The method of manufacturing a pole piece according to claim 17, wherein,

The provision of a composite current collector includes:

The hot melt adhesive has a center line parallel to the second direction, and the distance between the center lines of the two hot melt adhesives located on two sides of the adjacent two current collector bodies opposite to each other in the first direction is not more than 0.5mm.

19. The method of manufacturing a pole piece according to claim 16, wherein,

20. Method for manufacturing a pole piece according to any of the claims 15-19, characterized in that,