Battery monomer, composite pole piece preparation device and method, battery device and energy storage device

Abstract

The invention belongs to the technical field of batteries, and provides a battery monomer, a composite pole piece preparation device and method, a battery device and an energy storage device.The battery monomer comprises an electrode assembly, the electrode assembly comprises a positive pole piece and a negative pole piece, the positive pole piece and / or the negative pole piece are / is a composite pole piece, the composite pole piece comprises a pole piece body and a diaphragm, and the pole piece body is connected with a tab; the diaphragm is adhered to the surface of one side of the pole piece body and avoids the tab; a diaphragm is arranged on the pole piece body, a bonding layer is arranged between the diaphragm and the pole piece body and is made of a high polymer material, the pole piece body comprises a first side edge and a second side edge, the extension direction of the first side edge is a first direction, the extension direction of the second side edge is a second direction, the pole piece body is coated with the bonding layer in the first direction, and the bonding layer is of a discontinuous structure and is provided with a hollow area. The invention aims to prevent the phenomena of wrinkling, damage and warping of the diaphragm and dislocation between the diaphragm and pole pieces as much as possible, and reduce the risks of lithium precipitation and short circuit.

Description

Technical Field

[0001] The present application belongs to the field of battery technology, and in particular relates to a battery cell, a composite pole piece preparation device and method, a battery device and an energy storage device. Background Art

[0002] Battery devices are used more and more widely. Whether it is new energy vehicles or other electrical equipment, battery devices can be used. Battery devices include battery cells, and battery cells include electrode assemblies. The electrode assemblies are prepared in the form of alternating stacking and winding of negative electrode sheets, diaphragms, positive electrode sheets, and diaphragms. Due to factors such as process fluctuations, the diaphragm is prone to wrinkling, breakage, and warping. When the diaphragm is wrinkled and warped, it hinders the movement of lithium ions, and lithium deposition is likely to occur at the wrinkled and warped positions. At the same time, the electrode sheets and diaphragms are prone to relative slippage and dislocation. The relative slippage, dislocation, and damage to the diaphragm result in a greater risk of short circuit between the positive and negative electrode sheets. Summary of the invention

[0003] In view of the above problems, the present application provides a battery cell, a composite pole piece preparation device and method, a battery device and an energy storage device, aiming to prevent the diaphragm from wrinkling, breakage, warping and misalignment with the pole piece as much as possible, thereby reducing the risk of lithium plating and short circuit.

[0004] In the first aspect, the present application provides a battery cell, including an electrode assembly, the electrode assembly including a positive electrode sheet and a negative electrode sheet, the positive electrode sheet and / or the negative electrode sheet is a composite electrode sheet, the composite electrode sheet includes a electrode sheet body and a diaphragm, the electrode sheet body is connected to a pole ear, the diaphragm is bonded to one side surface of the electrode sheet body and avoids the pole ear; an adhesive layer is provided between the diaphragm and the electrode sheet body, the material of the adhesive layer is a polymer material, the electrode sheet body includes a first side edge and a second side edge, the extension direction of the first side edge is a first direction, and the extension direction of the second side edge is a second direction, the adhesive layer is applied to the electrode sheet body along the first direction, and the adhesive layer has a non-continuous structure and has a hollow area. In the battery cell of this embodiment, the diaphragm and the pole piece body of the electrode assembly are an integrated structure, that is, the diaphragm is attached to the surface of one side of the pole piece body, and the diaphragm and the pole piece body will not be misaligned, so that the pole piece body (such as the positive pole piece body) bonded with the diaphragm is kept in a reliable isolation state from the adjacent pole piece body (such as the negative pole piece body), reducing the risk of short circuit between the pole piece bodies, and the diaphragm is attached to the pole piece body, so that the risk of wrinkling, damage, and warping of the diaphragm itself during winding will be reduced, and the risk of lithium deposition at the corresponding position of the pole piece body is also reduced; the material of the bonding layer is a polymer material. The bonding layer has viscosity, so it can firmly bond the pole piece body and the diaphragm to form a whole, avoiding the phenomenon of relative displacement, and the polymer material has high chemical stability; the pole piece body includes a first side edge and a second side edge, the extension direction of the first side edge is the first direction, and the extension direction of the second side edge is the second direction, and the bonding layer is coated on the pole piece body along the first direction. In this way, the distribution is uniform and reasonable, which is conducive to mutual bonding with the diaphragm; the bonding layer is a discontinuous structure and has a hollow area. The hollow area can be infiltrated with electrolyte to enhance ion conduction. And because of the hollow area, the hollow area can also provide space for accommodation when the pole piece body expands.

[0005] In one embodiment of the first aspect, the bonding layer is in a grid, stripe or lattice shape. When the bonding layer is dispersed between the two in the form of a grid, stripe or lattice, it is preferably evenly distributed to reduce the risk of uneven metal ion deintercalation and embedding caused by uneven distribution of the bonding layer.

[0006] In one embodiment of the first aspect, the adhesive layer is located at the circumferential edge of the pole piece body. The distribution position of the adhesive layer can meet the connection strength requirements between the pole piece body and the diaphragm, and the large area in the center of the pole piece body is not provided with the adhesive layer and can be filled with electrolyte, that is, soaked with electrolyte.

[0007] In an embodiment of the first aspect, the distribution area of ​​the adhesive layer is larger than one quarter of the area of ​​the pole piece body. The distribution area is set to be larger than one quarter of the area of ​​the pole piece body, which also ensures the firmness of the connection.

[0008] In an embodiment of the first aspect, the adhesive layer includes one or more of polyvinylidene fluoride, styrene butadiene rubber, sodium carboxymethyl cellulose, polyacrylic acid, and polyacrylonitrile. The above materials will not hinder the movement of ions, or the degree of hindrance is small, and can fully meet the use requirements without deteriorating lithium precipitation.

[0009] In an embodiment of the first aspect, the material of the diaphragm includes one or more of polypropylene, polyethylene, styrene-butadiene rubber, polyacrylate, and polyvinylidene fluoride. Firstly, these materials are all insulating materials, which can well isolate the pole pieces from each other and achieve insulation.

[0010] In a second aspect, the present application further provides a composite pole piece preparation device, which is used to prepare the composite pole piece included in the battery cell provided in any one of the above embodiments, and comprises: a first rotating roller, the first rotating roller being used to pass around the strip-shaped substrate forming the diaphragm, and the movement speed of the strip-shaped substrate wound around the first rotating roller is equal to the linear speed of the first rotating roller; A second roller is disposed downstream of the first roller, and is used to simultaneously bypass the strip sheet for preparing the pole piece body and the strip substrate wound from the first roller, so that the strip sheet and the strip substrate are bonded to form a composite body, and the moving speed of the composite body is equal to the linear speed of the second roller, and the linear speed of the second roller is greater than the linear speed of the first roller; a spraying device, disposed upstream of the second rotating roller, for spraying an adhesive layer onto a surface of the strip-shaped sheet for bonding to the strip-shaped substrate; and The cutting device is arranged downstream of the second roller and is used to cut the composite body to form the composite electrode piece. Through the continuous rotation of the first roller and the second roller, the strip substrate and the strip sheet can be continuously compounded. Before lamination, the strip substrate is stretched by the speed difference of the two rollers to adjust various parameters of the diaphragm, realizing automatic adjustment with high efficiency, and a firm connection is achieved by means of the adhesive layer of the spraying device, and finally a composite electrode piece that meets the requirements is formed by cutting of the cutting device.

[0011] In an embodiment of the second aspect, the linear speed of the first roller is V1, the linear speed of the second roller is V2, and 3<V2 / V1<15. When the speeds of the first roller and the second roller meet this condition, the strip substrate can be stretched and adjusted within a required range, so that the diaphragm can better meet the use requirements.

[0012] In an embodiment of the second aspect, 5<V2 / V1<10. This can achieve a better stretching effect.

[0013] In one embodiment of the second aspect, the composite electrode sheet preparation device further comprises a winding roller, which is used to wind up the composite body wound from the second rotating roller. A composite body accommodating structure is provided, which can accommodate a large number of strip sheets and strip substrate composite bodies, thereby facilitating storage for subsequent cutting and use, and also realizing continuous production and storage of composite bodies on the basis of occupying limited space.

[0014] In an embodiment of the second aspect, the composite pole piece preparation device further includes: An extrusion device disposed upstream of the first roller, for extruding the melt; and A plurality of stretching rollers arranged upstream of the first roller are used to sequentially pass over the melt and longitudinally stretch the melt to obtain the strip-shaped substrate. A generation and production form of the strip-shaped substrate is provided, and the strip-shaped substrate can be quickly formed by extrusion and stretching processing, thereby realizing continuous production and greatly improving efficiency.

[0015] In an embodiment of the second aspect, the extrusion device comprises: An extruder, wherein the extruder has a discharge die head, wherein the discharge die head is used to extrude the melt, and the distance between the discharge die head and the adjacent first stretching roller is adjustable; and The feeding mechanism is used to feed the extruder. The raw materials can be melted and extruded at high temperature to form a melt, and the feeding mechanism continuously feeds the raw materials, and cooperates with the extruder to realize continuous automatic production and improve production efficiency. The distance between the discharge die head and the third rotating roller is adjustable, so that the thickness of the melt can be adjusted, and finally the thickness of the diaphragm can be adjusted.

[0016] In one embodiment of the second aspect, the composite electrode preparation device further comprises a cooling device, which is disposed on one side of the stretching roller and is used to cool the melt to accelerate its temperature drop, accelerate the cooling and molding of the melt, and quickly form a strip-shaped substrate.

[0017] In a third aspect, the present application further provides a method for preparing a composite pole piece, which is used to prepare the composite pole piece included in the battery cell provided in any one of the above embodiments, and comprises: The diaphragm raw material is prepared into a colloidal melt; The melt is passed through a plurality of stretching rollers for stretching and cooling to form a tape-shaped substrate; The strip-shaped substrate wound from the plurality of stretching rollers is stretched, and is laminated and bonded with the strip-shaped sheet body through the adhesive layer to form a composite body, wherein the strip-shaped sheet body is used to form a pole piece body; The composite body is cut to form a composite pole piece. The composite pole piece can be produced quickly, and the melt is stretched and cooled and the strip substrate is stretched during the preparation process, so that various parameters of the diaphragm can be effectively adjusted, including material characteristic parameters such as porosity, thickness, and air permeability, thereby ensuring the molding quality of the diaphragm and meeting the use requirements.

[0018] In an embodiment of the third aspect, the step of preparing the membrane raw material into a colloidal melt comprises: conveying the raw material to an extruder, and extruding the melt through the extruder. In this embodiment, the raw material is melted and extruded through an extruder, which is not only fast but also realizes continuous production, and the raw material is prepared into a melt structure that can form a membrane.

[0019] In one embodiment of the third aspect, the step of stretching the strip-shaped substrate wound off from the plurality of stretching rollers and laminating and bonding the strip-shaped substrate with the strip-shaped sheet through the adhesive layer to form a composite body comprises: The adhesive layer is sprayed on the surface of the strip-shaped sheet, and the strip-shaped sheet and the strip-shaped substrate that is wound out of the stretching roller are attached to each other at the composite roller through the adhesive layer and are simultaneously wound out of the composite roller to form the composite body. The adhesive layer greatly improves the connectivity between the strip-shaped sheet and the strip-shaped substrate, so that the finally formed diaphragm and the pole piece body maintain a good integration effect.

[0020] In one embodiment of the third aspect, the linear speed of the strip substrate when it is wound around the stretching roller is V1, and the linear speed of the composite body on the composite roller is V2, and V2 is greater than V1. In this way, the strip substrate between the stretching roller and the composite roller is stretched, thereby adjusting various parameters of the later diaphragm.

[0021] In one embodiment of the third aspect, 3<V2 / V1<15. This embodiment also provides a specific relationship between V2 and V1, that is, V2 is 3 to 15 times of V1. Under this speed ratio, effective stretching of the strip substrate can be achieved.

[0022] In an embodiment of the third aspect, 5<V2 / V1<10. Within this range, a better stretching effect can be achieved.

[0023] In one embodiment of the third aspect, the extruder has a discharge die, and the gap between the discharge die and the first stretching roller is adjustable. In this embodiment, the distance between the discharge die and the stretching roller is adjustable, which has better operability and can adjust the melt winding thickness according to the thickness requirements of the diaphragm and the stretching requirements, which is very convenient.

[0024] In a fourth aspect, the present application further provides a battery device, comprising the battery cell provided by any one of the above embodiments, to improve the reliability of the battery device.

[0025] In a fifth aspect, the present application further provides an energy storage device, comprising the battery device provided in the above embodiment, wherein the battery device is used to store or provide electrical energy, and the reliability of the energy storage device is also improved.

[0026] In a sixth aspect, the present application further provides an electrical device, comprising the battery device provided in the above embodiment or the energy storage device provided in the above embodiment.

[0027] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0029] In the attached picture: Figure 1 A schematic diagram of the structure of a vehicle according to some embodiments of the present application; Figure 2 A schematic diagram of the structure of a battery device provided in some embodiments of the present application; Figure 3 A schematic diagram of the structure of a composite electrode preparation device provided in some embodiments of the present application; Figure 4 A schematic diagram of the structure of a composite pole piece provided in some embodiments of the present application; Figure 5 A schematic structural diagram of a pole piece body provided with an adhesive layer of a continuous planar structure according to some embodiments of the present application; Figure 6 A schematic diagram of the structure of a pole piece body provided with a lattice-shaped adhesive layer provided in some embodiments of the present application; Figure 7 A schematic diagram of the structure of a pole piece body provided with a stripe-shaped adhesive layer provided in some embodiments of the present application; Figure 8 A schematic structural diagram of a pole piece body provided with a grid-shaped adhesive layer in some embodiments of the present application.

[0030] The reference numerals in the specific implementation manner are as follows: 1000. Vehicles; 100, battery device; 200, controller; 300, motor; 10. Battery cell; 11. Composite electrode; 111. Electrode body; 112. Diaphragm; 14. First roller; 15. Second roller; 16. Strip substrate; 17. Strip sheet; 18. Spraying device; 19. Unwinding roller; 20. Winding roller; 21. Third roller; 22. Fourth roller; 23. Melt; 24. Extrusion device; 241. Extruder; 242. Discharge die; 243. Feeding mechanism; 25. Composite; 26. Electrode ear; 27. Material tank; 2. Stretching roller; 3. Adhesive layer. DETAILED DESCRIPTION

[0031] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0033] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0034] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0035] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0036] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0037] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0038] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0039] At present, from the perspective of market development, the application of battery devices is becoming more and more extensive. Battery devices are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric cars, as well as military equipment and aerospace and other fields. With the continuous expansion of the application field of battery devices, the market demand is also constantly expanding.

[0040] The battery device may include a plurality of battery cells, each of which includes an electrode assembly and an electrolyte, and the electrode assembly is composed of a positive electrode sheet, a negative electrode sheet, and a separator.

[0041] The positive electrode sheet, negative electrode sheet and separator can be in a wound form or a stacked form. When the winding form is adopted, the separator and the electrode sheet are in a non-fixed state. Due to factors such as process fluctuations during winding, the separator is prone to wrinkling, warping, and damage. The wrinkling and warping of the separator will increase the resistance or path of lithium ion migration at that position, and lithium deposition will occur at the corresponding position of the negative electrode sheet. When the separator is damaged or the separator slips and misaligns, there will be a greater risk of short circuit between the positive electrode sheet and the negative electrode sheet. Especially for new batteries, such as metal batteries, for metal batteries, the active metal will grow along the edge of the electrode sheet. In this case, the misalignment of the separator is particularly prone to short circuit between the positive and negative electrodes, resulting in a decrease in the performance of the battery cell.

[0042] Based on the above considerations, an embodiment of the present application provides a battery cell 10, which aims to reduce the phenomenon of wrinkling, breakage, warping of the diaphragm and misalignment with the pole piece, and reduce the risk of lithium plating and short circuit.

[0043] The present application also provides a battery device 100 , comprising the above-mentioned battery cell 10 .

[0044] The embodiment of the present application further provides an electrical device having the battery device 100 , that is, an electrical device using the battery device 100 as a power source.

[0045] The embodiment of the present application also provides an energy storage device or energy storage system using the battery device 100 as an energy storage element, which can increase the safety of the electrical device and the energy storage system.

[0046] The battery device 100 (Battery Apparatus) mentioned in the embodiment of the present application may include one or more battery cell assemblies for providing voltage and capacity. The battery cell assembly (Battery Cell Assembly) may include multiple battery cells, and the multiple battery cells are connected in series, in parallel or in hybrid connection through a busbar component, and hybrid connection refers to a mixture of series connection and parallel connection.

[0047] In some embodiments, the battery device may be a battery pack, which includes a case and one or more battery cell assemblies, wherein the battery cell assemblies are accommodated in the case.

[0048] As an example, the battery cell assembly may be a battery module, and the battery cell assembly may be accommodated in the box by fixing the battery module in the box.

[0049] As an example, the battery cell assembly may also be housed in the case by directly fixing a plurality of battery cells to the case.

[0050] As an example, the box may include a first box and a second box. The first box and the second box are buckled together to form a closed space inside the box to accommodate the battery cell assembly. The closure here can be sealed or unsealed. The first box can be a top cover or a bottom plate.

[0051] As an example, the box body may include a top cover, a frame and a bottom plate. The top cover and the bottom plate are respectively connected to the frame, so that a closed space is formed inside the box body to accommodate the battery cell assembly.

[0052] In some embodiments, the box body can be used as a part of the chassis structure of the vehicle. For example, part of the box body can become at least a part of the floor of the vehicle, or part of the box body can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0053] In some embodiments, the battery cell includes an electrode assembly, and in some cases, the electrode assembly includes a positive electrode sheet, a negative electrode sheet, and a separator. The electrode assembly mainly relies on the movement of metal ions between the positive electrode sheet and the negative electrode sheet to work. The positive electrode sheet includes a positive electrode collector and a positive electrode active material layer, the positive electrode active material layer is coated on the surface of the positive electrode collector, the positive electrode collector not coated with the positive electrode active material layer protrudes from the positive electrode collector coated with the positive electrode active material layer, and the positive electrode collector not coated with the positive electrode active material layer serves as a positive electrode ear. Taking lithium-ion batteries as an example, the material of the positive electrode collector can be aluminum, and the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganese oxide, etc. The negative electrode sheet includes a negative electrode collector and a negative electrode active material layer, the negative electrode active material layer is coated on the surface of the negative electrode collector, the negative electrode collector not coated with the negative electrode active material layer protrudes from the negative electrode collector coated with the negative electrode active material layer, and the negative electrode collector not coated with the negative electrode active material layer serves as a negative electrode ear. The material of the negative electrode collector can be copper, and the negative electrode active material can be carbon or silicon, etc. In order to ensure that a large current can pass without melting, the number of positive tabs is multiple and stacked together, and the number of negative tabs is multiple and stacked together. The material of the diaphragm can be PP (polypropylene) or PE (polyethylene).

[0054] The technical solutions described in the embodiments of the present application are applicable to various electrical devices using battery devices, wherein the electrical devices may be vehicles, mobile phones, portable devices, laptop computers, ships, spacecraft, electric toys, and electric tools, etc. The vehicle may be a fuel vehicle, a gas vehicle, or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle, or an extended-range vehicle, etc.; the spacecraft includes airplanes, rockets, space shuttles, and spacecrafts, etc.; the electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc.; the electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools, and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. The embodiments of the present application do not impose any special restrictions on the above-mentioned electrical devices.

[0055] The battery device 100 disclosed in the embodiment of the present application can be used in, but not limited to, electrical devices such as vehicles, ships, or aircraft. The electrical device can use a power system having the battery device 100 disclosed in the present application.

[0056] For the convenience of description, the following embodiments are described by taking the electric device provided in the embodiments of the present application as a vehicle as an example.

[0057] Please refer to Figure 1 , Figure 1 A schematic diagram of the structure of a vehicle 1000 provided for some embodiments of the present application. The vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery device is provided inside the vehicle 1000, and the battery device may be provided at the bottom, head or tail of the vehicle 1000. The battery device may be used to power the vehicle 1000, for example, the battery device may be used as an operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300, and the controller 200 is used to control the battery device to power the motor 300, for example, for starting, navigating and driving the vehicle 1000.

[0058] In some embodiments of the present application, the battery device 100 can not only serve as an operating power source for the vehicle 1000, but also serve as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0059] See also Figure 2 , Figure 4-Figure 8A battery cell 10 provided in an embodiment of the present application includes an electrode assembly, the electrode assembly includes a positive electrode sheet and a negative electrode sheet, the positive electrode sheet and / or the negative electrode sheet is a composite electrode sheet 11, the composite electrode sheet 11 includes a electrode sheet body 111 and a diaphragm 112, the electrode sheet body 111 is connected with a pole ear 26, the diaphragm 112 is bonded to a side surface of the electrode sheet body 111 and avoids the pole ear 26 of the electrode sheet body 111; an adhesive layer 3 is provided between the diaphragm 12 and the electrode sheet body 111, the material of the adhesive layer 3 is a polymer material, the electrode sheet body 111 includes a first side edge and a second side edge, the extension direction of the first side edge is a first direction, and the extension direction of the second side edge is a second direction, the adhesive layer 3 is coated on the electrode sheet body 111 along the first direction, and the adhesive layer 3 is a discontinuous structure and has a hollow area.

[0060] Specifically, see Figure 4 This embodiment provides a composite pole piece 11, which includes a pole piece body 111 in addition to a diaphragm 112, and the diaphragm 112 and the pole piece body 111 form an integrated structure. Specifically, the composite pole piece 11 can be a positive pole piece and / or a negative pole piece.

[0061] The specific configuration of the composite electrode 11 is that the diaphragm 112 is bonded to one side surface of the electrode body 111, so that the diaphragm 112 and the electrode body 111 are integrated, and the diaphragm 112 is not bonded to the pole ear 26 of the electrode body 111, so that the pole ear 26 can be welded to the adapter. A gap can be formed between the diaphragm 112 and the electrode body 111, so that the electrolyte can enter.

[0062] In the battery cell 10 of the present embodiment, the diaphragm 112 and the pole piece body 111 of the electrode assembly are of an integrated structure, that is, the diaphragm 112 is adhered to the surface of one side of the pole piece body 111, and the diaphragm 112 and the pole piece body 111 will not be misaligned, so that the pole piece body 111 (for example, the positive pole piece body) adhered with the diaphragm 112 and the adjacent pole piece body 111 (for example, the negative pole piece body) maintain a reliable isolation state, reducing the risk of short circuit between the pole piece bodies 111, and the diaphragm 112 is attached to the pole piece body 111, so that the risk of wrinkling, damage, and warping of the diaphragm 112 itself during winding will be reduced, and the risk of lithium deposition at the corresponding position of the pole piece body 111 is also reduced.

[0063] An adhesive layer 3 is provided between the diaphragm 112 and the pole piece body 111 , and the material of the adhesive layer 3 is a polymer material.

[0064] The diaphragm 112 is connected to the pole piece body 111 via an adhesive layer 3 , and the adhesive layer 3 does not react with the electrolyte to ensure effective bonding between the diaphragm 112 and the pole piece body 111 .

[0065] Specifically, the adhesive layer 3 is disposed between the diaphragm 112 and the pole piece body 111, which can increase the connection strength between the diaphragm 112 and the pole piece body 111, increase the stability and firmness of the integrated structure, and at the same time, the integrated structure also reduces the risk of fracture of the pole piece body 111 to a certain extent, and increases the strength. In addition, the chemical properties of the adhesive layer 3 are stable, do not react with the electrolyte, and do not participate in the deintercalation reaction of ions, meeting the use requirements.

[0066] The adhesive layer 3 is sticky, so it can firmly bond the electrode body 111 and the diaphragm 112 to form a whole, thereby avoiding the relative displacement phenomenon. The polymer material has high chemical stability.

[0067] In some embodiments, the chemical stability of the adhesive layer 3 needs to be adapted to the working state and environment of the corresponding battery cell 10. For example, when the normal working temperature of the battery cell 10 is below 80°, the adhesive layer 3 does not decompose at a temperature below 80°, nor does it react with the electrolyte, the separator 112, the active material, etc., so as to adapt to the normal working temperature of the electrode assembly and maintain the viscosity continuously.

[0068] For another example, when the output voltage of the battery cell 10 is 2-4.2V, the adhesive layer 3 needs to not decompose within the voltage range and not react with the electrolyte, the separator 112, the active material, etc.

[0069] The pole piece body 111 includes a first side and a second side. The first side extends in a first direction, and the second side extends in a second direction. The adhesive layer 3 is applied to the pole piece body 111 along the first direction.

[0070] Specifically, the pole piece body 111 is generally rectangular in the unfolded state, specifically a long rectangle, so generally the pole piece body 111 includes a first side and a second side, the first side can be the longer side of the pole piece body 111, and the second side can be the shorter side of the pole piece body 111. This embodiment provides that the adhesive layer 3 extends and distributes along the first direction, that is, the direction of the first side, so that the distribution can be uniform and reasonable, which is conducive to mutual bonding with the diaphragm 112.

[0071] The adhesive layer 3 is a discontinuous structure and has a hollow area.

[0072] Specifically, the discontinuous structure means that the distribution is not continuous in a planar manner, but has an intermittent distribution form, so the area where the adhesive layer 3 is not distributed is a hollow area.

[0073] like Figure 6 , Figure 7 and Figure 8The adhesive layer 3 is a discontinuous structure and has a hollow area. The adhesive layer 3 is a discontinuous structure, and its material can be a material that is conducive to electrolyte infiltration and ion permeation, or a material with slightly poor electrolyte infiltration performance and low ion permeability. It is arranged in a local area between the electrode body 111 and the diaphragm 112, and is in a grid, stripe or lattice shape.

[0074] Specifically, the present embodiment provides that the adhesive layer 3 is disposed in a local area between the pole piece body 111 and the diaphragm 112, that is, the space between the two is not filled with the adhesive layer 3, and the space between the two except the adhesive layer 3 does not affect the infiltration of the electrolyte and the conduction of ions, that is, the hollow area can be infiltrated with electrolyte to enhance the conduction of ions. And because of the hollow area, the hollow area can also provide a space for accommodation when the pole piece body 111 expands.

[0075] In the above embodiment, the hollow area between the diaphragm 112 and the pole piece body 111 without the adhesive layer 3 forms a gap for accommodating the electrolyte, which minimizes the influence of the adhesive layer 3 on the electrolyte infiltration effect. In addition, the gap can be used to provide space for the pole piece body 111 to expand.

[0076] In some cases, the adhesive layer 3 may also be distributed in the form of a continuous planar structure.

[0077] Therefore, the structure of the adhesive layer 3 can be various, such as Figure 5 , can be a whole surface structure that extends continuously in a two-dimensional plane, such as Figure 6-Figure 8 , or it can be a discontinuous structure with a hollow area.

[0078] In some embodiments, Figure 6-Figure 8 When the adhesive layer 3 is a discontinuous structure, the adhesive layer 3 may be in a grid shape, a stripe shape or a dot matrix shape.

[0079] The discontinuous structure includes a dot matrix structure, a stripe structure, a grid structure, and may also include a strip-shaped or dot-shaped structure that is only bonded to the edge of the pole piece body 111. When the material of the bonding layer 3 is not conducive to the penetration of metal ions, a discontinuous structure is preferred so as not to affect the charge and discharge performance of the battery cell 10; when the material of the bonding layer 3 is conducive to the penetration of metal ions, a continuous full-surface structure may be selected but is not limited to it. Similarly, when the material of the bonding layer 3 is not conducive to the infiltration of the electrolyte, a discontinuous structure is preferred so as not to affect the charge and discharge performance of the battery cell 10; when the material of the bonding layer 3 is conducive to the infiltration of the electrolyte, a continuous full-surface structure may be selected but is not limited to it.

[0080] Specifically, when the bonding layer 3 is dispersedly arranged between the two in the form of a grid, stripe or dot matrix, it is preferably evenly distributed to reduce the risk of uneven metal ion deintercalation and embedding caused by the uneven distribution of the bonding layer. Of course, the total area and setting position of the bonding layer 3 are based on the connection strength requirements between the pole piece body 111 and the diaphragm 112.

[0081] In some embodiments, the adhesive layer 3 is located at the circumferential edge of the pole piece body 111 .

[0082] Specifically, when the adhesive layer 3 is in a dot matrix shape, it can be dispersed near the edge of the pole piece body 111 and distributed in sequence along the extension direction of the edge, or when it is in a stripe shape, it can also be arranged along the position close to the edge. The stripe-shaped adhesive layer 3 can be set to be parallel to the edge of the pole piece body 111.

[0083] The distribution position of the adhesive layer 3 provided in this embodiment can meet the connection strength requirement between the pole piece body 111 and the diaphragm 112, and the large area in the center of the pole piece body 111 is not provided with the adhesive layer 3, which can be filled with electrolyte, that is, soaked with electrolyte. It is more suitable for the situation that the material of the adhesive layer 3 is not conducive to electrolyte infiltration or the penetration of metal ions.

[0084] In some embodiments, the distribution area of ​​the adhesive layer 3 is greater than one quarter of the area of ​​the pole piece body 111 .

[0085] Specifically, when the adhesive layer 3 is a discontinuous structure, the distribution area of ​​the adhesive layer 3 is set to be larger than one quarter of the area of ​​the pole piece body 111, which also ensures the firmness of the connection.

[0086] When the adhesive layer 3 is a continuous planar structure, in order to ensure effective bonding between the diaphragm 112 and the pole piece body 111 , the adhesive layer 3 should also occupy more than one quarter of the area of ​​the pole piece body 111 .

[0087] like Figure 5 When the adhesive layer 3 is in a continuous planar structure, the area is larger than one quarter of the area of ​​the pole piece body 111. When the adhesive layer 3 provided in this embodiment is in a continuous planar structure, the material of the adhesive layer 3 is selected to facilitate the penetration of metal ions and the infiltration of electrolyte, and the area is larger than one quarter of the area of ​​the pole piece body 111. While ensuring the normal charge and discharge performance of the battery cell 10, the bonding strength can be greatly increased, so that the diaphragm 112 and the pole piece body 111 form a solid whole, further enhance the integration effect, and avoid the diaphragm 112 from warping, wrinkling, or even misalignment with the pole piece body 111.

[0088] In some embodiments, the material of the adhesive layer 3 includes one or more of polyvinylidene fluoride, styrene-butadiene rubber, sodium carboxymethyl cellulose, polyacrylic acid, and polyacrylonitrile.

[0089] The above materials have good corrosion resistance, oxidation resistance, wear resistance, flexibility, high expansion strength and impact resistance, and excellent heat resistance and insulation effect. And the ion permeability is high and will not deteriorate lithium precipitation.

[0090] Due to the above advantages, the effective connection between the diaphragm 112 and the pole piece body 111 can be effectively ensured during long-term use, and the heat-resistant effect and insulation are also increased, which also increases the safety of the battery cell 10 during use.

[0091] In some embodiments, the material of the diaphragm 112 includes one or more of polypropylene, polyethylene, styrene-butadiene rubber, polyacrylate, and polyvinylidene fluoride. The diaphragm 112 is made of the above materials because they are all insulating materials that can well isolate and insulate the pole pieces 111 from each other.

[0092] In some embodiments, the composite electrode 11 can be selected as a negative electrode. Since lithium deposition usually occurs in the negative electrode, it is necessary to increase the space of the negative electrode to accommodate lithium ions, so the size of the negative electrode is usually designed to be larger, that is, the area of ​​the negative electrode is larger than the area of ​​the positive electrode. Therefore, in this embodiment, the separator 112 is bonded to the electrode body 111 of the negative electrode, which can effectively cover the electrode body 111 of the negative electrode, so as to isolate the positive electrode and the negative electrode as much as possible, and reduce the risk of short circuit between the negative electrode and the positive electrode.

[0093] In some embodiments, the positive electrode sheet and the negative electrode sheet can be selected as a composite electrode sheet 11 at the same time. This is equivalent to covering the two electrode sheets with opposite polarities with the diaphragm 112, which plays a double-layer insurance effect, further strengthens the isolation effect of the positive and negative electrode sheets, and greatly reduces the risk of short circuit.

[0094] The electrode body 111 includes a current collector and an active material on the surface of the current collector. When the composite electrode 11 is a negative electrode, the current collector of the electrode body 111 is made of the material required for the negative electrode, specifically copper foil, and the active material is a negative electrode active material. When the composite electrode 11 is a positive electrode, the current collector of the electrode body 111 is made of the material required for the positive electrode, specifically aluminum foil, and the active material is a positive electrode active material. The same is true for the second electrode.

[0095] The present application also provides a specific embodiment of a composite electrode preparation device, such as Figure 3 , used to prepare the composite pole piece 11 included in the battery cell 10 provided in any of the above embodiments, including a first rotating roller 14, a second rotating roller 15, a spraying device 18, and a cutting device.

[0096] The first rotating roller 14 is used to bypass the strip-shaped substrate 16 forming the diaphragm 112 . The moving speed of the strip-shaped substrate 16 wound around the first rotating roller 14 is equal to the linear speed of the first rotating roller 14 .

[0097] The second roller 15 is disposed downstream of the first roller 14, and is used to simultaneously bypass the strip sheet 17 for preparing the pole piece body 111 and the strip substrate 16 wound from the first roller 14, so that the strip sheet 17 and the strip substrate 16 are attached to form a composite body 25, and the moving speed of the composite body 25 is equal to the linear speed of the second roller 15, and the linear speed of the second roller 15 is greater than the linear speed of the first roller 14; The spraying device 18 is disposed upstream of the second rotating roller 15 and is used to spray the adhesive layer 3 onto the surface of the strip-shaped sheet 17 for bonding to the strip-shaped substrate 16; The cutting device is disposed downstream of the second rotating roller 15 and is used for cutting the composite body 25 of the strip-shaped substrate 16 and the strip-shaped sheet body 17 to form a composite pole piece 11 .

[0098] Specifically, the first roller 14 and the second roller 15 are cylindrical or approximately cylindrical roller structures, and the two are located at different positions and can be arranged to be parallel to each other. The two can rotate around their own axes under the drive of a power mechanism, and the driving mechanism can be a servo motor, etc., which can control the start and stop and movement speed of the first roller 14 and the second roller 15.

[0099] The strip substrate 16 refers to a strip-shaped structure used to form the diaphragm 112, which is the substrate for forming the diaphragm 112. The strip substrate 16 is wound on the first roller 14 and moves with the rotation of the first roller 14. It should be noted that the movement speed of the strip substrate 16 wound on the first roller 14 is equal to the movement speed of the first roller 14, that is, the two move synchronously and will not move relative to each other. The first roller 14 is set and the strip substrate 16 is wound around it so that the strip substrate 16 can achieve continuous movement and be continuously laid on the surface of the strip sheet 17 to achieve adhesion, thereby improving production efficiency.

[0100] The strip sheet 17 refers to a substrate for forming the pole piece body 111 . After the strip sheet 17 and the strip substrate 16 are attached to each other, they can be cut by a cutting device to obtain a composite pole piece 11 .

[0101] The function of the second roller 15 is to simultaneously pass the strip-shaped substrate 16 and the strip-shaped sheet 17 to bond them together. Specifically, the strip-shaped substrate 16 and the strip-shaped sheet 17 pass the second roller 15 at the same time, that is, pass in a stacked form to bond them together. When the strip-shaped substrate 16 is passed out from the first roller 14, it passes the second roller 15 together with the strip-shaped sheet 17.

[0102] Before the strip substrate 16 is attached to the strip sheet 17, it is necessary to perform appropriate stress stretching operation on the strip substrate 16, so that the material characteristic parameters such as porosity, thickness, and air permeability after forming the diaphragm 112 can be adjusted. Specifically, the means of implementation is that the movement speed of the strip substrate 16 wound on the first roller 14 is equal to the linear speed of the first roller 14, and when the strip substrate 16 and the strip sheet 17 are wound together on the second roller 15, the movement speed of the strip substrate 16 and the strip sheet 17 is equal to the linear speed of the second roller 15, or the strip substrate 16 and the strip sheet 17 wound on the second roller 15 move synchronously with the second roller 15. Since the linear speed of the second roller 15 is greater than the linear speed of the first roller 14, the strip substrate 16 will be stretched, so that the porosity, thickness, air permeability, etc. after forming the diaphragm 112 can be adjusted. Specifically, the stretching force can be adjusted according to the parameter setting requirements, which can be achieved by adjusting the speed difference between the second roller 15 and the first roller 14 .

[0103] In order to strengthen the bonding strength between the strip substrate 16 and the strip sheet 17, the present embodiment further provides a spraying device 18, which is used to spray the adhesive layer 3 onto the surface of the strip sheet 17, and is specifically sprayed before the strip sheet 17 is wound around the second roller 15, that is, before being bonded to the strip substrate 16, which can effectively strengthen the bonding strength. The spraying amount and spraying frequency of the spraying device 18 can also be adjusted and set.

[0104] When the strip substrate 16 and the strip sheet 17 pass through the second rotating roller 15, they are bonded together to form a composite body 25, which can be stored in the form of a roll. When the composite pole piece 11 is manufactured, it is wound out and cut. The composite pole piece 11 can be cut according to its size to form a single composite pole piece 11, and the pole ear 26 is cut out at the same time during the cutting process.

[0105] The effect of this embodiment is that through the continuous rotation of the first roller 14 and the second roller 15, the strip substrate 16 and the strip sheet 17 can be continuously compounded, and the strip substrate 16 is stretched by the speed difference of the two rollers before bonding to adjust various parameters of the diaphragm 112, thereby realizing automatic adjustment with high efficiency, and a firm connection is achieved with the help of the adhesive layer 3 of the spraying device 18, and finally a composite electrode 11 that meets the requirements is formed by cutting by the cutting device.

[0106] In some embodiments, the linear velocity of the first rotating roller 14 is V1, and the linear velocity of the second rotating roller 15 is V2, then 3<V2 / V1<15.

[0107] This embodiment provides a linear speed relationship between the first roller 14 and the second roller 15, that is, 3<V2 / V1<15. When the speeds of the first roller 14 and the second roller 15 meet this condition, the strip substrate 16 can be stretched and adjusted within a required range, so that the diaphragm 112 can better meet the use requirements.

[0108] Furthermore, 5<V2 / V1<10, and a better stretching effect can be achieved within this ratio range.

[0109] In some embodiments, Figure 3 The composite electrode preparation device also includes a reel 19 , and the strip-shaped sheet 17 is wound around the reel 19 and passes around the second rotating roller 15 after being unwound.

[0110] Specifically, before the strip sheet 17 is wound around the second rotating roller 15 together with the strip substrate 16, in order to achieve continuous production and save the space occupied by the strip sheet 17, the strip sheet 17 is wound on a unwinding roller 19, and the unwinding roller 19 rotates to unwind the strip sheet 17, thereby achieving continuous automated production, and the unwinding speed can also be determined by controlling the rotation speed of the unwinding roller 19.

[0111] In some embodiments, Figure 3 The composite electrode preparation device also includes a winding roller 20, which is used to wind up the composite body 25 wound off from the second rotating roller 15.

[0112] Specifically, the composite body 25 formed after the strip sheet 17 and the strip substrate 16 are bonded together by the second rotating roller 15 will continue to move, that is, continue to move to the winding roller 20, so that the composite body 25 is stored. When it is necessary to form a composite pole piece 11, the winding roller 20 is unwound in the reverse direction, so that the composite body 25 is cut by the cutting device into a suitable size and the pole ear 26 is cut out to form a composite pole piece 11.

[0113] The effect of this embodiment is that a containing structure for the complex 25 is provided, which can accommodate a large number of strip sheets 17 and strip substrate 16 complexes 25, thereby facilitating storage for subsequent cutting and use, and also realizing continuous production and storage of the complex 25 on the basis of occupying a limited space.

[0114] In some embodiments, Figure 3 The composite electrode preparation device also includes an extrusion device 24 and a plurality of stretching rollers 2 arranged upstream of the first roller 14.

[0115] The extrusion device 24 extrude a melt 23 for forming a strip-shaped substrate 16 ; the plurality of stretching rollers 2 are used to sequentially pass around the melt 23 and longitudinally stretch the melt 23 to obtain the strip-shaped substrate 16 .

[0116] Specifically, two stretching rollers 2 can be selected, specifically a third roller 21 and a fourth roller 22, the third roller 21 is used to bypass the melt 23; the fourth roller 22 is used to bypass the melt 23 wound off from the third roller 21, and a strip-shaped substrate 16 is formed when it is wound off the fourth roller 22, and the wound strip-shaped substrate 16 bypasses the first roller 14.

[0117] Specifically, the melt 23 is in the form before forming the strip substrate 16, and is a semi-molten gel structure. It is extruded from the extruder 24, has a high temperature, and has good plasticity, so it needs to be stretched and shaped to form the strip substrate 16. This embodiment provides a stretching roller 2 to wrap the melt 23, and stretch it as the stretching roller 2 rotates. Specifically, after the melt 23 is extruded from the extruder 24, it can first bypass the third roller 21, then bypass the fourth roller 22, and the strip substrate 16 can be formed when it is wound out of the fourth roller 22. This process is called the cast sheet stage, and the melt 23 is stretched and quickly cooled by the third roller 21 and the fourth roller 22 to obtain a polyolefin casting sheet with high orientation and low crystallinity, and cooled and crystallized under the stress field of high-speed drawing to obtain a strip substrate 16 with a lamellar structure. After winding out of the fourth roller 22, the strip substrate 16 is wound around the first roller 14 for subsequent operations.

[0118] The effect of this embodiment is that it provides a form of generating and producing a strip-shaped substrate 16. The strip-shaped substrate 16 can be quickly formed through extrusion and stretching processing, and continuous production is achieved, which greatly improves efficiency.

[0119] In some embodiments, Figure 3 The extrusion device 24 includes an extruder 241 and a feeding mechanism 243 .

[0120] The extruder 241 has a discharge die 242 , which is used to extrude the melt 23 . The distance between the discharge die 242 and the first adjacent stretching roller 2 is adjustable. The feeding mechanism 243 is used to feed materials into the extruder 241 .

[0121] Specifically, the feeding mechanism 243 is connected to the extruder 241, and the feeding mechanism 243 has a feeding port, which can be connected to the material tank 27, so that the material is fed to the extruder 241 through the feeding mechanism 243. The material is a raw material for forming the diaphragm 112, which can be particles of polypropylene, polyethylene, styrene-butadiene rubber, polyacrylate, polyvinylidene fluoride, etc. The feeding mechanism 243 can melt the raw material particles at high temperature, and then extrude them through the extruder 241, specifically through the discharge die 242 of the extruder 241, to form a melt 23, and then the melt 23 bypasses a plurality of stretching rollers 2, specifically the third roller 21, the fourth roller 22, and then bypasses the first roller 14. The distance between the discharge die 242 and the first stretching roller 2, that is, the third roller 21, is adjustable, so that when the melt 23 is extruded, the thickness of the melt 23, that is, the thickness around the third roller 21, can be adjusted.

[0122] The effect of this embodiment is that the raw material can be melted and extruded at high temperature to form a melt 23, and the material is continuously fed through the feeding mechanism 243, and the extruder 241 is used to realize continuous automatic production, thereby improving production efficiency. The distance between the discharge die 242 and the third rotating roller 21 is adjustable, so that the thickness of the melt 23 can be adjusted, and finally the thickness of the diaphragm 112 can be adjusted.

[0123] In some embodiments, the composite electrode preparation device further includes a cooling device, which is disposed on one side of the stretching roller 2 and is used to cool the melt 23 .

[0124] Specifically, when the melt 23 is on the stretching roller 2, in addition to stretching, the melt 23 is also cooled so that the strip-shaped substrate 16 can be formed. Therefore, a cooling device is also provided on one side of the stretching roller 2. The cooling device can be specifically an air cooling device, which can blow cold air toward the melt 23 on the stretching roller 2 to accelerate the cooling, accelerate the cooling and molding of the melt 23, and quickly form the strip-shaped substrate 16.

[0125] The present application also provides a specific embodiment of a composite pole piece preparation method, which is used to prepare the composite pole piece 11 included in the battery cell 10 provided in any of the above embodiments, comprising: The raw material of the diaphragm 112 is prepared into a colloidal melt 23; The melt 23 is passed through a plurality of stretching rollers 2 for stretching and cooling to form a strip-shaped substrate 16; The strip-shaped substrate 16 wound from the plurality of stretching rollers 2 is stretched, and laminated and bonded with the strip-shaped sheet 17 through the adhesive layer 3 to form a composite body 25, wherein the strip-shaped sheet 17 is used to form the pole piece body 111; The composite body 25 is cut to form composite pole pieces 11 .

[0126] Specifically, the raw materials for forming the diaphragm 112 can be particles of polypropylene, polyethylene, styrene-butadiene rubber, polyacrylate, polyvinylidene fluoride, etc. The raw materials are melted and extruded to form a melt 23. At this time, the melt 23 is a plastic soft structure with a high temperature. First, the melt 23 needs to be stretched for the first time, that is, stretched by multiple stretching rollers 2, and the melt 23 is stretched in turn by passing through multiple stretching rollers 2, and the melt 23 is cooled during the process, and finally a strip substrate 16 is formed. The strip substrate 16 is used to form the diaphragm 112. The strip substrate 16 needs to be stretched for the second time, and then it can be bonded with the strip sheet 17. Specifically, the strip substrate 16 wound from the stretching roller 2 is stretched for the second time, and finally bonded with the strip sheet 17 to form a composite 25. After the composite 25 is cut, a composite pole piece 11 can be formed.

[0127] The present embodiment provides a specific method for preparing a composite electrode piece 11, which can quickly produce a composite electrode piece 11. During the preparation process, the melt 23 is stretched and cooled, and the strip substrate 16 is stretched, etc., which can effectively adjust various parameters of the diaphragm 112, including material characteristic parameters such as porosity, thickness, and permeability, thereby ensuring the molding quality of the diaphragm 112 and meeting the use requirements.

[0128] It should be noted that the stretching roller 2 may be the third roller 21 and the fourth roller 22 in the above device embodiment, and the number of stretching rollers 2 may be set as required.

[0129] In some embodiments, preparing the raw material of the diaphragm 112 into a gel-like melt 23 includes: conveying the raw material to an extruder 241 , and extruding the melt 23 through the extruder 241 .

[0130] Specifically, the raw materials can be stored, and when used for production, the raw materials can be transported to the material tank 27, and the material tank 27 is connected to the feeding mechanism 243 of the extrusion device 24. The raw materials are fed through the feeding mechanism 243 and melted at high temperature, and then the melt 23 is extruded from the extruder 241.

[0131] In this embodiment, the raw material is melted and extruded by the extrusion device 24 , which is not only fast but also realizes continuous production, and the raw material is prepared into a melt 23 structure that can form the diaphragm 112 .

[0132] In some embodiments, the strip-shaped substrate 16 wound off from a plurality of stretching rollers 2 is stretched and laminated and bonded with the strip-shaped sheet 17 via an adhesive layer 3 to form a composite body 25, including: spraying the adhesive layer 3 onto the surface of the strip-shaped sheet 17, the strip-shaped sheet 17 and the strip-shaped substrate 16 wound off from the stretching rollers 2 are bonded at a composite roller via the adhesive layer 3 and are simultaneously wound off from the composite roller to form a composite body 25.

[0133] Specifically, before the strip-shaped sheet 17 is attached to the strip-shaped substrate 16, the adhesive layer 3 is sprayed on the surface of the side for attaching to the strip-shaped substrate 16. After the strip-shaped substrate 16 is wound out of the stretching roller 2, it is wound onto the composite roller together with the strip-shaped sheet 17, and the adhesive layer 3 is located between the strip-shaped sheet 17 and the strip-shaped substrate 16 to attach the two. After the strip-shaped substrate 16 is wound out of the stretching roller 2, it can also be wound around the first roller 14 mentioned above and then composited with the strip-shaped sheet 17. The first roller 14 has the same linear speed as the stretching roller 2. The composite roller can be the second roller 15 mentioned above.

[0134] The effect of this embodiment is that the bonding layer 3 greatly improves the connectivity between the strip sheet 17 and the strip substrate 16 , so that the finally formed diaphragm 112 and the pole piece body 111 maintain a good integrity.

[0135] In some embodiments, an implementation method for stretching the strip substrate 16 is provided, wherein the linear speed of the strip substrate 16 when it wraps around the stretching roller 2 is V1, and the linear speed of the composite 25 moving on the composite roller is V2, and V2 is greater than V1, so as to stretch the strip substrate 16 before composite.

[0136] Specifically, the speed of the strip substrate 16 when it wraps around the stretching roller 2 is V1, that is, the speed at which the strip substrate 16 and the stretching roller 2 move synchronously is V1, that is, the linear speed of the stretching roller 2 is V1, and the speed at which the composite roller drives the composite body 25 to move synchronously is V2, that is, the linear speed of the composite roller is V2, and V2 is greater than V1, so that the strip substrate 16 between the stretching roller 2 and the composite roller is stretched, thereby adjusting the various parameters of the later diaphragm 112.

[0137] The effect of this embodiment is that this stretching method also realizes the stretching operation during winding, and completes the stretching process of the strip substrate 16 without stopping the machine. It is not only fast, but also the stretching force of each section of the strip substrate 16 in the length direction is balanced and uniform, so that the consistency of each diaphragm 112 after subsequent cutting is better.

[0138] This embodiment also provides a specific relationship between V2 and V1, that is, V2 is 3 to 15 times of V1, that is, 3<V2 / V1<15. Under this speed ratio, effective stretching of the strip-shaped substrate 16 can be achieved.

[0139] Furthermore, 5<V2 / V1<10, which can achieve better stretching effect.

[0140] It should be noted that the composite roller may be the second roller 15 in the above device embodiment.

[0141] In some embodiments, the extruder 241 has a discharge die 242, and the gap between the discharge die 242 and the first stretching roller 2 is adjustable. The discharge die 242 is used to extrude the melt 23, and when extruded, it will be wound around the first stretching roller 2, so the gap between the discharge die 242 and the first stretching roller 2 determines the winding thickness of the melt 23 to a certain extent, and also determines the degree of stretching required later and the thickness of the diaphragm 112 finally formed. Therefore, the present embodiment sets the spacing between the discharge die 242 and the stretching roller 2 to be adjustable, which has better operability, and the winding thickness of the melt 23 can be adjusted according to the thickness requirements of the diaphragm 112 and the stretching requirements, which is very convenient.

[0142] The present application also provides a battery device 100, comprising the battery cell 10 provided in any of the above embodiments.

[0143] Since the battery device 100 includes the battery cell 10 , the reliability of the battery device 100 is improved.

[0144] The present application also provides an energy storage device, including the above-mentioned battery device 100, and the battery device 100 is used to store or provide electrical energy.

[0145] The energy storage device of this embodiment includes one or more battery clusters to increase the voltage and capacity of the energy storage device. The battery cluster may include multiple battery devices 100, and the multiple battery devices 100 are connected in series through a busbar to increase the voltage of the energy storage device. When the energy storage device includes multiple battery clusters, the multiple battery clusters are connected in parallel to increase the capacity of the energy storage device.

[0146] Energy storage devices can be used in energy storage power stations, wind power generation systems, solar power generation systems, mobile power systems or temporary power supply systems. Energy storage devices can store electrical energy as needed and output it at the appropriate time. For example, energy storage devices can store electrical energy when electricity consumption is low, and provide electrical energy to relevant users or electrical equipment during peak electricity consumption.

[0147] In some embodiments, the energy storage device is an energy storage container or an energy storage cabinet.

[0148] In some embodiments, the energy storage device may include a cabinet and one or more battery clusters, wherein the battery clusters are housed in the cabinet.

[0149] In some embodiments, the energy storage device may include modules such as a thermal management module, a main control module, a master control module, a power distribution module, and a fire protection module.

[0150] As an example, the thermal management module may include a liquid cooling unit that provides cooling liquid for regulating the temperature of the battery cells 10 to each battery device 100 through a pipeline.

[0151] As an example, the main control module can be used as a battery management unit of a battery cluster to monitor and manage the battery cluster. The main control module can monitor information such as the current, voltage, power or temperature of the battery cluster. For example, the charging and discharging current and voltage of the battery cluster can be controlled. The main control module includes a slave battery management unit SBMU (SBMU), a fusion switch and other modules.

[0152] As an example, the master control module can be used as a battery management unit of an energy storage device to monitor and manage the energy storage device. The master control module can monitor information such as the current, voltage, power, state of charge or temperature of the energy storage device. For example, the charging and discharging current, voltage, etc. of the energy storage device can be controlled. As an example, the master control module includes an insulation monitoring module IMM (Insulation Monitoring Module, abbreviated as IMM), a master battery management unit MBMU (Master Battery Management Unit, MBMU), Ethernet ETH (EtherNet, ETH) and a fiber optic conversion module and other modules.

[0153] As an example, the fire protection module includes a control panel, a detector, an alarm device, etc., which are used to detect, alarm or extinguish fire in the energy storage system. As an example, the power distribution module can be used to distribute power to modules in the energy storage device that require power.

[0154] This embodiment may also provide an energy storage system, including a power conversion device and the above-mentioned energy storage device, wherein the power conversion device is used to electrically connect the power generation device and the energy storage device.

[0155] The energy storage system provided in the embodiments of the present application may be any power system that requires an energy storage device.

[0156] The energy storage system may include one or more energy storage devices and a power converter system (PCS), and the power converter system is used to connect between the power generation equipment and the energy storage device. The power generation equipment is used to generate electrical energy, and the electrical energy generated by the power generation equipment can be stored in the energy storage device through the power converter. As an example, the power generation equipment may specifically be a solar panel, a hydropower generation equipment, a thermal power generation equipment, a wind power generation equipment, etc. Among them, the specific type of the power generation equipment is not limited in this application.

[0157] This embodiment further provides an electrical device, which may include the above-mentioned battery device 100 or the above-mentioned energy storage device, and may also include the above-mentioned energy storage system.

[0158] The present application may also provide a charging network, including a charging pile and the above-mentioned energy storage device and / or the above-mentioned energy storage system, wherein the energy storage device is used to provide electrical energy to the charging pile. The charging pile is electrically connected to the battery device 100 in the energy storage device through a cable, and the battery device 100 can provide its stored electrical energy to the charging pile. The charging pile has one or more connectors, which are used to connect to an electrical device (such as a vehicle 1000) so as to replenish energy to the electrical device.

[0159] The energy storage device can be located inside the charging pile (such as an integrated storage and charging machine) or outside the charging pile.

[0160] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery cell, characterized in that: It includes an electrode assembly, the electrode assembly includes a positive electrode sheet and a negative electrode sheet, the positive electrode sheet and / or the negative electrode sheet is a composite electrode sheet, the composite electrode sheet includes a electrode sheet body and a diaphragm, the electrode sheet body is connected with a pole ear, the diaphragm is bonded to one side surface of the electrode sheet body and avoids the pole ear; an adhesive layer is provided between the diaphragm and the electrode sheet body, the material of the adhesive layer is a polymer material, the electrode sheet body includes a first side edge and a second side edge, the extension direction of the first side edge is a first direction, the extension direction of the second side edge is a second direction, the adhesive layer is coated on the electrode sheet body along the first direction, the adhesive layer is a non-continuous structure and has a hollow area.

2. The battery cell according to claim 1, characterized in that: The adhesive layer is in a grid shape, a stripe shape or a dot matrix shape.

3. The battery cell according to claim 1, characterized in that: The bonding layer is located at the circumferential edge of the pole piece body.

4. The battery cell according to claim 1, characterized in that: The distribution area of ​​the bonding layer is greater than one quarter of the area of ​​the pole piece body.

5. The battery cell according to any one of claims 1 to 4, characterized in that: The material of the bonding layer includes one or more of polyvinylidene fluoride, styrene-butadiene rubber, sodium carboxymethyl cellulose, polyacrylic acid, and polyacrylonitrile.

6. The battery cell according to any one of claims 1 to 4, characterized in that: The material of the diaphragm includes one or more of polypropylene, polyethylene, styrene-butadiene rubber, polyacrylate, and polyvinylidene fluoride.

7. A composite electrode preparation device, characterized in that: The composite pole piece used to prepare the battery cell according to any one of claims 1 to 6 comprises: a first rotating roller, the first rotating roller being used to pass around the strip-shaped substrate forming the diaphragm, and the movement speed of the strip-shaped substrate wound around the first rotating roller is equal to the linear speed of the first rotating roller; A second roller is disposed downstream of the first roller, and is used to simultaneously bypass the strip sheet for preparing the pole piece body and the strip substrate wound from the first roller, so that the strip sheet and the strip substrate are bonded to form a composite body, and the moving speed of the composite body is equal to the linear speed of the second roller, and the linear speed of the second roller is greater than the linear speed of the first roller; a spraying device, disposed upstream of the second rotating roller, for spraying an adhesive layer onto a surface of the strip-shaped sheet for bonding to the strip-shaped substrate; and A cutting device is arranged downstream of the second rotating roller and is used for cutting the composite body to form the composite pole piece.

8. The composite electrode preparation device according to claim 7, characterized in that: The linear speed of the first rotating roller is V1, and the linear speed of the second rotating roller is V2, then 3<V2 / V1<15.

9. The composite electrode preparation device according to claim 8, characterized in that: 5<V2 / V1<10.

10. The composite electrode preparation device according to claim 7, characterized in that: The composite pole piece preparation device further comprises a winding roller, and the winding roller is used to wind up the composite body wound off from the second rotating roller.

11. The composite electrode preparation device according to claim 7, characterized in that: The composite pole piece preparation device also includes: An extrusion device disposed upstream of the first roller, for extruding the melt; and A plurality of stretching rollers arranged upstream of the first roller are used to sequentially bypass the melt and longitudinally stretch the melt to obtain the strip-shaped substrate.

12. The composite electrode preparation device according to claim 11, characterized in that: The extrusion device comprises: An extruder, wherein the extruder has a discharge die head, wherein the discharge die head is used to extrude the melt, and the distance between the discharge die head and the adjacent first stretching roller is adjustable; and A feeding mechanism is used for feeding materials into the extruder.

13. The composite electrode preparation device according to claim 11, characterized in that: The composite pole piece preparation device further comprises a cooling device, which is arranged on one side of the stretching roller and is used for cooling the melt.

14. A method for preparing a composite electrode, characterized in that: The composite pole piece used to prepare the battery cell according to any one of claims 1 to 6 comprises: The diaphragm raw material is prepared into a colloidal melt; The melt is passed through a plurality of stretching rollers for stretching and cooling to form a tape-shaped substrate; The strip-shaped substrate wound from the plurality of stretching rollers is stretched, and is laminated and bonded with the strip-shaped sheet body through the adhesive layer to form a composite body, wherein the strip-shaped sheet body is used to form a pole piece body; The composite body is cut to form composite pole pieces.

15. The method for preparing a composite electrode according to claim 14, characterized in that: The step of preparing the membrane raw material into a gelatinous melt comprises: conveying the raw material to an extruder, and extruding the melt through the extruder.

16. The method for preparing a composite electrode according to claim 14, characterized in that: The step of stretching the strip-shaped substrate wound from the plurality of stretching rollers and laminating and bonding the strip-shaped substrate with the strip-shaped sheet through the adhesive layer to form a composite body comprises: An adhesive layer is sprayed on the surface of the strip-shaped sheet, and the strip-shaped sheet and the strip-shaped substrate wound off the stretching roller are attached to each other at a composite roller through the adhesive layer and are simultaneously wound off the composite roller to form the composite body.

17. The method for preparing a composite electrode according to claim 16, characterized in that: The linear speed of the strip substrate when it is wound around the stretching roller is V1, and the linear speed of the composite body moving on the composite roller is V2, and V2 is greater than V1.

18. The method for preparing a composite electrode according to claim 17, characterized in that: 3<V2 / V1<15.

19. The method for preparing a composite electrode according to claim 18, characterized in that: 5<V2 / V1<10.

20. The method for preparing a composite electrode according to claim 15, characterized in that: The extruder has a discharge die head, and the gap between the discharge die head and the first stretching roller is adjustable.

21. A battery device, characterized in that: A battery cell comprising the battery cell according to any one of claims 1 to 6.

22. An energy storage device, characterized in that: Comprising the battery device as claimed in claim 21, the battery device is used to store or provide electrical energy.

23. An electrical device, characterized in that: Comprising the battery device as claimed in claim 21 or the energy storage device as claimed in claim 22.

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