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

Abstract

The invention belongs to the technical field of batteries, and provides a battery monomer, a pole piece preparation method, a battery device, an energy storage device and a power utilization device.The battery monomer comprises an electrode assembly, the electrode assembly comprises a first pole piece, the first pole piece is a composite pole piece, and the composite pole piece comprises a pole piece body and a diaphragm; a tab is arranged on one side of the pole piece body; the diaphragm wraps the pole piece body, the tab is exposed out of the diaphragm, the diaphragm comprises a first diaphragm and a second diaphragm, the first diaphragm and the second diaphragm are formed by folding the same flat film, and the first diaphragm and the second diaphragm are respectively used for covering two side surfaces of the pole piece body; a bent connecting part between the first diaphragm and the second diaphragm is used for covering one end, far away from the tab, of the pole piece body; two edges of the first diaphragm and the second diaphragm are connected to enable the diaphragm and the pole piece body to form a whole, the diaphragm is provided with a through hole, and the through hole is located at one end of the diaphragm away from the tab. The invention aims to prevent the diaphragm from warping, wrinkling, folding and dislocation with a pole piece, and reduce the lithium precipitation short circuit risk.

Description

Technical Field

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

[0002] With the rise of new energy equipment represented by new energy vehicles, battery devices have become a key source of power. Battery devices include battery cells, which include electrode assemblies. The electrode assemblies include positive electrodes, negative electrodes and separators. When preparing the electrode assemblies, the positive electrodes, negative electrodes and separators are alternately stacked and wound. Due to factors such as process fluctuations, the separators are prone to warping, wrinkling and folding, which will increase the resistance or path of lithium ion migration at that position of the separator, resulting in lithium deposition at the corresponding position of the negative electrode. Even when the separator and the electrode slip and dislocation occur, it is likely to cause a short circuit between the positive and negative electrodes of the electrode assembly. Summary of the invention

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

[0004] The battery cell provided in the present application includes an electrode assembly, wherein the electrode assembly includes a first pole piece, wherein the first pole piece is a composite pole piece, and the composite pole piece includes: A pole piece body, with a pole ear on one side; and A diaphragm, wherein the diaphragm wraps the pole piece body, and the pole ear is exposed outside the diaphragm. The diaphragm includes a first diaphragm and a second diaphragm, wherein the first diaphragm and the second diaphragm are formed by folding the same flat film in half, and the first diaphragm and the second diaphragm are respectively used to cover the two side surfaces of the pole piece body, and the bent connection portion between the first diaphragm and the second diaphragm is used to cover the end of the pole piece body away from the pole ear; the edge of the first diaphragm and the edge of the second diaphragm are connected to each other so that the diaphragm and the pole piece body are integrated, and the diaphragm is also provided with a through hole for electrolyte to pass through, and the through hole is located at the end of the diaphragm away from the pole ear.

[0005] In this example, in the battery cell of this embodiment, the diaphragm of the composite pole piece wraps the pole piece body, so that the pole piece body is well isolated from other pole pieces. The diaphragm and the pole piece body are arranged together, so the risk of misalignment is reduced, thereby reducing the risk of short circuit between the pole pieces. In addition, the diaphragm is attached to the pole piece body, and is not a separate sheet structure separated from the pole piece. In this way, the risk of warping, wrinkling, and folding of the diaphragm itself during winding will be reduced, and the risk of lithium deposition at the corresponding position of the negative pole piece is reduced. The structure and layout of the diaphragm are simple and easy to operate, and can form an effective wrapping of the pole piece body; the first diaphragm and the second diaphragm are connected to each other through the edge, so that a chamber, i.e., a bag-like structure, can be formed between the first diaphragm and the second diaphragm, so that the pole piece body can be effectively wrapped and an integrated structure can be formed with the pole piece body; the diaphragm is also provided with a through hole for electrolyte to pass through, so that the electrolyte enters between the diaphragm and the pole piece body, which is convenient for the entry of the electrolyte; the through hole is located at the end of the diaphragm away from the pole ear. This way, the through hole is biased to reduce the impact on the isolation effect of the positive and negative electrode sheets.

[0006] In some embodiments of the first aspect, the edge of the first diaphragm and the edge of the second diaphragm are bonded or hot-melt connected. These two connection forms are simple and convenient, both can achieve fast and effective connection, and keep the insulation of the diaphragm intact.

[0007] In some embodiments of the first aspect, the electrode assembly further includes a second pole piece, which is also the composite pole piece, and the first pole piece and the second pole piece have opposite polarities and are adjacently arranged.

[0008] This is equivalent to wrapping the diaphragm with opposite polarities, which has the effect of double-layer insurance, further enhancing the isolation effect and greatly reducing the risk of short circuit.

[0009] In some embodiments of the first aspect, there are multiple through holes, and the multiple through holes are arranged in sequence along the length direction of the diaphragm. In order to allow the electrolyte to be smoothly injected into the diaphragm. Therefore, this embodiment provides multiple through holes, which are arranged along the length direction of the diaphragm. The intervals between the multiple through holes can be the same, that is, they are evenly arranged.

[0010] In some embodiments of the first aspect, the through hole is provided at the connecting portion.

[0011] In some embodiments of the first aspect, the through hole is provided at the connection portion of the integrated diaphragm. It is also relatively easy to open the through hole at the connection portion, and the electrolyte can enter the diaphragm from both sides, which has a better effect.

[0012] In some embodiments of the first aspect, the first electrode is 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 electrode body is selected as the negative electrode, so that the short circuit risk can be better reduced after the negative electrode is wrapped.

[0013] In a second aspect, the present application also provides a method for preparing a pole piece, which is used to prepare a composite pole piece included in a battery cell described in any of the above embodiments.

[0014] In an embodiment of the second aspect, comprising: preparing a diaphragm having an open chamber; Placing the pole piece body in the chamber and positioning the pole lug outside the chamber; The opening of the chamber is closed so that the diaphragm wraps the pole piece body and the pole ear is exposed outside the diaphragm. This embodiment provides a method for preparing a composite pole piece, which can quickly and efficiently realize the production of a composite pole piece, thereby improving the safety of electrode assemblies and battery cells.

[0015] In an embodiment of the second aspect, a flat film used to form a diaphragm is folded in half to form a first diaphragm and a second diaphragm, and the first diaphragm and the second diaphragm surround the diaphragm in which the chamber is set. This embodiment provides a preparation form of the diaphragm, which has a simple process and is easy to prepare, and can quickly form the diaphragm and wrap the pole piece body.

[0016] In an embodiment of the second aspect, the through hole is provided at the bent connection portion between the first diaphragm and the second diaphragm. The through hole is formed on the connection portion so that the through holes can be located on the first diaphragm and the second diaphragm respectively, facilitating the electrolyte to enter the two sides.

[0017] In an embodiment of the second aspect, the edge of the first film at the opening position and the edge of the second film at the opening position are bonded or hot-melted to close the opening of the chamber. This connection form is simple, convenient and fast.

[0018] In an embodiment of the second aspect, after connecting the first diaphragm and the second diaphragm, the method further includes cutting the first diaphragm and the second diaphragm along one side of the connection position to remove excess parts, so that the appearance of the diaphragm is smoother.

[0019] In a third aspect, the present application further provides a battery device, comprising the battery cell provided by any one of the above embodiments, thereby improving the safety of the battery device.

[0020] In a fourth 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, thereby improving the safety of the energy storage device.

[0021] In a fifth aspect, the present application further provides an electrical device, comprising the battery device and / or the energy storage device provided in the above embodiments, which also improves the safety of the electrical device.

[0022] 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

[0023] 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.

[0024] 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 pole piece provided in some embodiments of the present application; Figure 4 for Figure 3 A schematic diagram of the enlarged structure at A in the middle; Figure 5 A schematic diagram of the structure of a flattening film provided in some embodiments of the present application; Figure 6 A schematic diagram of the structure of a diaphragm formed by folding a flat film in half provided in some embodiments of the present application; Figure 7 A schematic diagram of the structure of the pole piece body provided in some embodiments of the present application.

[0025] 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 pole piece; 12. Pole piece body; 13. Pole ear; 14. Diaphragm; 15. Through hole; 16. First diaphragm; 17. Second diaphragm; 18. Connecting part. DETAILED DESCRIPTION

[0026] The following embodiments of the technical solution of the present application will be 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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).

[0032] 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.

[0033] 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.

[0034] 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 battery application fields, its market demand is also constantly expanding.

[0035] 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.

[0036] The positive electrode sheet, negative electrode sheet and diaphragm can be arranged in a winding form, which will form a layered structure. Since the diaphragm and the electrode sheet are separated, the diaphragm is prone to wrinkling, folding and warping due to process fluctuations and other factors during winding, which 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. There is even a greater risk of short circuit between the positive electrode sheet and the negative electrode sheet when slippage causes misalignment. Especially for new batteries, such as metal batteries, for metal batteries, active metals will grow along the edges of the electrode sheets. In this case, when the diaphragm is misaligned, it will be particularly easy to cause the positive and negative electrodes to short-circuit, resulting in a decrease in the performance of the battery cell.

[0037] Based on the above considerations, an embodiment of the present application provides a battery cell, which aims to prevent the diaphragm from warping, wrinkling, folding, and misalignment with the pole piece as much as possible, thereby reducing the risk of lithium plating and short circuit.

[0038] The present application also provides a battery device, comprising the above-mentioned battery cell.

[0039] The present application also provides an electric device having the above-mentioned battery device, that is, an electric device using the battery device as a power source. Various energy storage systems using the battery device as an energy storage element are also provided. This can increase the safety of the electric device and the energy storage system.

[0040] The battery apparatus mentioned in the embodiments of the present application may include one or more battery cell assemblies for providing voltage and capacity. The battery cell assembly may include multiple battery cells, which are connected in series, in parallel or in hybrid connection through a busbar component, where hybrid connection refers to a mixture of series connection and parallel connection.

[0041] In some embodiments, a battery cell assembly is generally formed by arranging a plurality of battery cells.

[0042] As an example, the battery cell assembly may be a battery module, which is formed by arranging and fixing a plurality of battery cells to form an independent module. As an example, the battery module may be formed by bundling a plurality of battery cells by a cable tie.

[0043] The battery cell includes an electrode assembly, which is composed of 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. 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. 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. 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. In order to ensure that a large current can be passed without melting, the number of positive pole ears is multiple and stacked together, and the number of negative pole ears is multiple and stacked together. The material of the separator can be PP (polypropylene) or PE (polyethylene). The electrode assembly can be a wound structure.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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 closed here means covered or closed, which can be sealed or unsealed. The first box can be a top cover or a bottom plate.

[0048] 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.

[0049] 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.

[0050] The technical solutions described in the embodiments of the present application are applicable to various electrical devices using battery cells, 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.

[0051] The battery device disclosed in the embodiment of the present application can be used in, but not limited to, electrical devices such as vehicles, ships, or aircraft. Electrical devices can use a power supply system having the battery device disclosed in the present application.

[0052] 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.

[0053] 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.

[0054] In some embodiments of the present application, the battery device 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.

[0055] See also Figures 2 to 7 A battery cell 10 provided in an embodiment of the present application includes an electrode assembly, the electrode assembly includes a first pole piece, the first pole piece is a composite pole piece 11, and the composite pole piece 11 includes a pole piece body 12 and a diaphragm 14.

[0056] A pole ear 13 is provided on one side of the pole piece body 12. The diaphragm 14 wraps the pole piece body 12, and the pole ear 13 is exposed outside the diaphragm 14. The diaphragm 14 includes a first diaphragm 16 and a second diaphragm 17. The first diaphragm 16 and the second diaphragm 17 are formed by folding the same flat film. The first diaphragm 16 and the second diaphragm 17 are used to cover the two side surfaces of the pole piece body 12 respectively, and the bent connecting portion 18 between the first diaphragm 16 and the second diaphragm 17 is used to cover the end of the pole piece body 12 away from the pole ear 13.

[0057] Specifically, see Figures 3 to 7 , this embodiment provides a composite electrode 11, which refers to a composite electrode 11 that includes a diaphragm 14 in addition to a electrode body 12, and the diaphragm 14 wraps the electrode body 12. The first electrode can be a positive electrode or a negative electrode, and the overall structure formed by the electrode body 12 and the diaphragm 14 forms the composite electrode 11. The electrode body 12 includes a current collector and an active material on the surface of the current collector. When the first electrode is a negative electrode, that is, the current collector of the electrode body 12 adopts the material required for the negative electrode, which can be copper foil, and the active material adopts the negative electrode active material. When the first electrode is a positive electrode, that is, the current collector of the electrode body 12 adopts the material required for the positive electrode, which can be aluminum foil, and the active material adopts the positive electrode active material.

[0058] The specific setting form of the composite pole piece 11 can be that the diaphragm 14 wraps the pole piece body 12, that is, covers the two side surfaces and the end side of the pole piece body 12, so that the diaphragm 14 and the pole piece body 12 are integrated, and the pole ear 13 on the pole piece body 12 is not wrapped by the diaphragm 14, so that the pole ear 13 can be welded to the adapter.

[0059] Specifically, this embodiment provides a specific implementation form in which the diaphragm 14 wraps the pole piece body 12. The diaphragm 14 includes two diaphragms, namely the first diaphragm 16 and the second diaphragm 17, which are arranged on both sides of the pole piece body 12, that is, the first diaphragm 16 and the second diaphragm 17 respectively cover the two side surfaces of the pole piece body 12. It can also be considered that the first diaphragm 16 and the second diaphragm 17 form a clamp for the pole piece body 12, and the bent connecting portion 18 formed by the folding of the first diaphragm 16 and the second diaphragm 17 covers the side of the pole piece body 12 away from the pole ear 13. There is a gap or void between the first diaphragm 16 and the second diaphragm 17 and the surface of the pole piece body 12, and the electrolyte can enter the gap or void.

[0060] The shape of the first diaphragm 16 and the shape of the second diaphragm 17 can be the same, and they are arranged on both sides of the pole piece body 12 and aligned with each other. Alternatively, the shape of the first diaphragm 16 and the shape of the second diaphragm 17 can be different so as to cover the pole piece body 12. It should be noted that the first diaphragm 16 and the second diaphragm 17 can be bonded to the surface of the pole piece body 12, but a gap or a void can also be formed to accommodate the electrolyte.

[0061] In this embodiment, the diaphragm 14 is a flat film before being folded, that is, the first diaphragm 16 and the second diaphragm 17 are two parts of the same flat film, and the reason why they are divided into the first diaphragm 16 and the second diaphragm 17 is that the flat film is folded in half.

[0062] The first diaphragm 16 and the second diaphragm 17 are arranged to be formed by folding a flat film in half. There is no need to separately arrange two films. They can be formed by folding in half. This is simple and convenient. After folding in half, one end portion, i.e., the connecting portion 18 of the first diaphragm 16 and the second diaphragm 17, is formed. This end portion does not need to be connected later, which also simplifies the manufacturing process.

[0063] For example, the flattened film may be rectangular, and the flattened film is folded in half along its central axis to form a first film sheet 16 and a second film sheet 17 having the same shape and size.

[0064] In the battery cell of this embodiment, the diaphragm 14 of the composite pole piece 11 wraps the pole piece body 12, so that the pole piece body 12 is well isolated from other pole pieces. The diaphragm 14 and the pole piece body 12 are arranged together to reduce the risk of misalignment, thereby reducing the risk of short circuit between pole pieces. In addition, the diaphragm 14 exists by being attached to the pole piece body 12, and is not a separate sheet structure separated from the pole piece. In this way, the risk of warping, wrinkling, and folding of the diaphragm 14 itself during winding will be reduced, reducing the risk of lithium deposition at the corresponding position of the negative pole piece. In addition, the structure and layout of the diaphragm 14 are simple and easy to operate, and can form an effective wrapping of the pole piece body 12.

[0065] It should be noted that the first electrode sheet may be a negative electrode sheet or a positive electrode sheet.

[0066] In some embodiments, the edge of the first diaphragm 16 and the edge of the second diaphragm 17 are connected to each other so that the diaphragm 14 and the pole piece body 12 are integrated.

[0067] Specifically, the shape of the first diaphragm 16 and the second diaphragm 17 can be slightly larger than the shape of the pole piece body 12. The first diaphragm 16 and the second diaphragm 17 can fit each other at the edge part, and are connected thereto so that a chamber, i.e., a bag-like structure, can be formed between the first diaphragm 16 and the second diaphragm 17, so that the pole piece body 12 can be effectively wrapped and an integrated structure can be formed with the pole piece body 12. The diaphragm 14 forms a bag-like structure, and the pole ear 13 extends from the diaphragm 14 of the bag-like structure. Alternatively, the first diaphragm 16 and the second diaphragm 17 form a chamber, and the pole piece body 12 is located in the chamber, and then the first diaphragm 16 and the second diaphragm 17 are matched to close the chamber, so that the pole piece body 12 is wrapped. The chamber of the bag-like structure formed by the diaphragm 14 is compatible with the shape and size of the structure of the pole piece body 12 except the pole ear 13, that is, it just wraps the pole piece body 12, so that the pole piece body 12 will not shake inside the diaphragm 14, and the effect is better.

[0068] The edge of the first diaphragm 16 and the edge of the second diaphragm 17 are connected to each other but may not be in a completely sealed connection, and the electrolyte can enter between the diaphragm 14 and the pole piece body 12 from there.

[0069] Exemplarily, the structure of the pole piece body 12 except the pole ear 13 is in a rectangular shape, so the first diaphragm 16 and the second diaphragm 17 can be adaptively arranged in a rectangular shape.

[0070] In some embodiments, the edge of the first film 16 and the edge of the second film 17 are bonded or heat-fused.

[0071] These two connection forms are simple and convenient. Hot melting is to heat the first diaphragm 16 and the second diaphragm 17 at a high temperature to make the molten parts of the two compatible, and then connect them after cooling. Or they can be connected by glue. Both forms can achieve fast and effective connection and keep the insulation of the diaphragm 14 intact.

[0072] In some embodiments, the electrode assembly further includes a second pole piece, which is also a composite pole piece 11 , and the first pole piece and the second pole piece have opposite polarities and are disposed adjacent to each other.

[0073] Specifically, this embodiment provides a second electrode, which is also a composite electrode 11, and the polarity of the first electrode and the second electrode are opposite, that is, if the first electrode is a negative electrode, the second electrode is a positive electrode, and if the first electrode is a positive electrode, the second electrode is a negative electrode. This is equivalent to the electrodes with opposite polarities being wrapped in the diaphragm 14, which has the effect of double-layer insurance, further enhancing the isolation effect, and greatly reducing the risk of short circuit.

[0074] In some embodiments, Figure 3 , Figure 4 and Figure 6The diaphragm 14 is also provided with a through hole 15 for allowing the electrolyte to pass through.

[0075] Specifically, the through hole 15 is used to pass the electrolyte, so that the electrolyte enters between the diaphragm 14 and the pole piece body 12, which is convenient for the electrolyte to enter. The diaphragm 14 wraps the pole piece body 12, but there can be a gap between the diaphragm 14 and the pole piece body 12 to accommodate the electrolyte, so the diaphragm 14 also has a through hole 15, so that the electrolyte can flow into the inside of the diaphragm 14 through the through hole 15. In this way, when the edges of the first diaphragm 16 and the second diaphragm 17 are sealed and connected, the electrolyte can enter through the through hole 15, or when the edges of the first diaphragm 16 and the second diaphragm 17 are not sealed and connected, the provision of the through hole 15 makes it more convenient for the electrolyte to enter.

[0076] In some embodiments, Figure 3 , Figure 4 and Figure 6 The diaphragm 14 is also provided with a through hole 15 for allowing electrolyte to pass through, and the through hole 15 is located at one end of the diaphragm 14 away from the pole ear 13.

[0077] The through hole 15 is specifically opened at the end of the diaphragm 14, specifically, one end of the first diaphragm 16 and one end of the second diaphragm 17, that is, a part of the entire through hole 15 is located on the first diaphragm 16, and the other part is located on the second diaphragm 17. Alternatively, it can be set on the first diaphragm 16 or the second diaphragm 17 separately.

[0078] Specifically, the present embodiment provides a setting position for the through hole 15. When only one of the two pole pieces with opposite polarities is a composite pole piece 11, the through hole 15 cannot be set on the large surface of the diaphragm 14, and the large surface refers to the surface used to cover both sides of the pole piece body 12, because this may affect the effect of the diaphragm 14 and may cause the possibility of short circuit between the two pole pieces with opposite polarities. Therefore, the through hole 15 provided in the present embodiment is set at the end of the diaphragm 14, specifically the end away from the side of the pole ear 13, so as to reduce the influence on the isolation effect, and the position of the through hole 15 is located at the end of the diaphragm 14 away from the pole ear 13, because the first diaphragm 16 and the second diaphragm 17 are originally connected to each other as a whole, and the connection effect is better, so the through hole 15 is set here to reduce the influence on the overall stability of the diaphragm 14.

[0079] In some embodiments, Figure 6 There are multiple through holes 15 , and the multiple through holes 15 are arranged in sequence along the length direction of the diaphragm 14 .

[0080] In order to allow the electrolyte to be smoothly injected into the separator 14, a plurality of through holes 15 are provided in this embodiment, and are arranged along the length direction of the separator 14. The intervals between the plurality of through holes 15 can be the same, that is, they are evenly arranged.

[0081] In some embodiments, Figure 5 and Figure 6 , the through hole 15 is provided at the connection portion 18. The connection portion 18 is located at an end away from the pole ear 13, and the through hole 15 can be provided, and it is also relatively easy to open the through hole 15 at the connection portion 18.

[0082] When the diaphragm 14 is folded in half, a connection portion 18 will be provided, which forms one end of the diaphragm 14. At the same time, the connection portion 18 is the end of the side away from the pole ear 13, and the through hole 15 can be arranged at the connection portion 18. And a part of the through hole 15 can be located on the first diaphragm 16, and the other part can be located on the second diaphragm 17. When the through holes 15 are located on the two diaphragms respectively, the electrolyte can enter the diaphragm 14 from both sides, and the effect is better.

[0083] In some embodiments, the first electrode is 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 first electrode is selected as a negative electrode, so that the risk of short circuit can be better reduced after wrapping.

[0084] The present application also provides a method for preparing a pole piece, which is used to prepare the composite pole piece 11 included in the battery cell 10 provided in any one of the above embodiments.

[0085] Specifically, the pole piece preparation method includes: Preparing a diaphragm 14 having an open chamber; The pole piece body 12 is placed in the chamber, and the pole ear 13 is located outside the chamber; The opening of the chamber is closed so that the diaphragm 14 wraps the pole piece body 12 and the pole ear 13 is exposed outside the diaphragm 14 .

[0086] Specifically, the diaphragm 14 is prepared first, and when preparing the diaphragm 14, the diaphragm 14 is formed into a cavity with an open portion, and the open portion is used to allow the pole piece body 12 to enter the diaphragm 14, and then the cavity is closed. The closure here may not be sealed, because the pole ear 13 must be exposed and the electrolyte can enter. When the pole piece body 12 is in the diaphragm 14, the pole ear 13 is exposed from the diaphragm 14, which does not affect the welding with the adapter. The edges of the diaphragm 14 on both sides of the pole ear 13 are respectively attached to the root position of the pole ear 13.

[0087] This embodiment provides a method for preparing a composite electrode sheet 11 , which can quickly and efficiently manufacture the composite electrode sheet 11 , thereby improving the safety of the electrode assembly and the battery cell 10 .

[0088] In some embodiments, a flat film used to form the diaphragm 14 is folded in half to form a first film sheet 16 and a second film sheet 17 , and the first film sheet 16 and the second film sheet 17 surround the diaphragm 14 in which the cavity is set.

[0089] Specifically, this embodiment provides a process for preparing the diaphragm 14. First, a flat film is selected. The flat film is a material for preparing the diaphragm 14. The flat film is a sheet structure, and the material can be polypropylene or polyethylene. The size of the flat film can be equal to or greater than twice the area of ​​the pole piece body 12, so that when folded, a first diaphragm 16 and a second diaphragm 17 with an area equal to or slightly larger than the pole piece body 12 can be formed. The folded position, that is, the connecting portion 18 of the first diaphragm 16 and the second diaphragm 17 is selected from the central axis of the flat film, so that the first diaphragm 16 and the second diaphragm 17 are the same in size and shape, and it is easier to form a cavity.

[0090] Regarding the formation of the chamber, when the first diaphragm 16 and the second diaphragm 17 are formed, the two are folded in half, and a chamber is formed between the two. Although the three sides of this chamber are open, the open part is the opening, but it can still be called a chamber. The pole piece body 12 is located in the chamber, and on both side surfaces of the pole piece body 12, the first diaphragm 16 and the second diaphragm 17 can cover the pole piece body 12, excluding the part covering the pole ear 13.

[0091] This embodiment provides a preparation method of the diaphragm 14 , which has a simple process and is convenient to prepare, and can quickly form the diaphragm 14 and wrap the pole piece body 12 .

[0092] In some embodiments, Figure 5 and Figure 6 A through hole 15 is provided at the position of the connection portion 18 bent between the first diaphragm 16 and the second diaphragm 17. In order to allow the electrolyte to enter the chamber better, a through hole 15 is also provided on the diaphragm 14, and the through hole 15 communicates the inside and outside of the diaphragm 14 chamber.

[0093] When the pole piece body 12 is placed between the first diaphragm 16 and the second diaphragm 17 , the edge of the pole piece body 12 may abut against the connecting portion 18 .

[0094] Specifically, when the pole piece body 12 contacts the connecting portion 18, it indicates that the pole piece body 12 contacts the inner end of the diaphragm 14. Contact refers to contact and limitation, so that the pole piece body 12 will not move relative to the diaphragm 14, making the integration of the diaphragm 14 and the pole piece body 12 better and the isolation effect more stable.

[0095] The connection portion 18 is an end portion of one side of the diaphragm 14. The through hole 15 is formed in the connection portion 18.

[0096] In some embodiments, the edge of the first film 16 at the opening position and the edge of the second film 17 at the opening position are bonded or hot-melt-connected to close the opening of the chamber.

[0097] When the chamber is closed, the first diaphragm 16 and the second diaphragm 17 are connected, and at this time, the edge of the pole piece body 12 is still against the connection position.

[0098] Specifically, the first diaphragm 16 and the second diaphragm 17 are folded in half to form a chamber with three open sides, where the opening is the open part. When the chamber is closed, the other three open parts except the connecting part 18 are closed, that is, the three edges of the first diaphragm 16 and the second diaphragm 17 are connected, which can be specifically hot-melt connection or bonding, but the position where the pole ear 13 is located does not need to be closed, and the pole ear 13 needs to be extended.

[0099] After the connection is completed, the edge of the internal pole piece body 12 abuts the connection position, and the connection position is a strip-shaped connection band along the extension direction of the first diaphragm 16 and the second diaphragm 17. The specific connection positions in each direction can be parallel to the corresponding edges of the pole piece body 12, and the edge of the pole piece body 12 also contacts the corresponding connection position from the inside of the diaphragm 14. The effect of this is that the edge abuts the connection position, indicating that there is no gap between the connection position and the pole piece body 12, and the pole piece body 12 is completely restrained in the diaphragm 14. The pole piece body 12 will not move relative to the diaphragm 14, and the two will not be misaligned, so that the isolation effect is better and more stable.

[0100] In some embodiments, after connecting the first film sheet 16 and the second film sheet 17 , the method further includes cutting the first film sheet 16 and the second film sheet 17 along one side of the connection position to remove excess parts.

[0101] Specifically, after the first diaphragm 16 and the second diaphragm 17 are connected, there may be a redundant portion, ie, an extra portion, outside the connection position, which can be cut off to make the diaphragm 14 look smoother.

[0102] The present application also provides a battery device 100, comprising the battery cell 10 provided in any of the above embodiments.

[0103] Since the battery device 100 includes the battery cell 10 , the use safety of the battery device 100 is improved.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] In some embodiments, the energy storage device is an energy storage container or an energy storage cabinet.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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.

[0112] 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.

[0113] 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.

[0114] 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.

[0115] The energy storage system provided in the embodiments of the present application may be any power system that requires an energy storage device.

[0116] 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.

[0117] This embodiment further provides an electrical device, which may include the above-mentioned battery device 100, the above-mentioned energy storage device or the above-mentioned energy storage system.

[0118] The present application may also provide a charging network, including a charging pile and the above-mentioned energy storage device 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.

[0119] The energy storage device can be located inside the charging pile (such as an integrated storage and charging machine) or outside the charging pile.

[0120] 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: The invention comprises an electrode assembly, wherein the electrode assembly comprises a first electrode piece, wherein the first electrode piece is a composite electrode piece, and the composite electrode piece comprises: A pole piece body, with a pole ear on one side; and A diaphragm, wherein the diaphragm wraps the pole piece body, and the pole ear is exposed outside the diaphragm. The diaphragm includes a first diaphragm and a second diaphragm, and the first diaphragm and the second diaphragm are formed by folding the same flat film in half. The first diaphragm and the second diaphragm are respectively used to cover the two side surfaces of the pole piece body, and the bent connection portion between the first diaphragm and the second diaphragm is used to cover the end of the pole piece body away from the pole ear; the edge of the first diaphragm and the edge of the second diaphragm are connected to each other so that the diaphragm and the pole piece body are integrated, and the diaphragm is also provided with a through hole for electrolyte to pass through, and the through hole is located at the end of the diaphragm away from the pole ear.

2. The battery cell according to claim 1, characterized in that: The edge of the first film and the edge of the second film are bonded or thermally melted.

3. The battery cell according to claim 1, characterized in that: The electrode assembly further includes a second pole piece, which is also the composite pole piece. The first pole piece and the second pole piece have opposite polarities and are adjacently arranged.

4. The battery cell according to any one of claims 1 to 3, characterized in that: There are a plurality of through holes, and the plurality of through holes are arranged in sequence along the length direction of the diaphragm.

5. The battery cell according to any one of claims 1 to 3, characterized in that: The through hole is arranged at the connecting portion.

6. The battery cell according to any one of claims 1 to 3, characterized in that: The first electrode sheet is a negative electrode sheet.

7. A method for preparing a pole piece, characterized in that: Used to prepare the composite pole piece included in the battery monomer described in any one of claims 1-6.

8. The method for preparing a pole piece according to claim 7, characterized in that: include: preparing a diaphragm having an open chamber; Placing the pole piece body in the chamber and positioning the pole lug outside the chamber; The opening of the chamber is closed so that the diaphragm wraps the pole piece body and the pole ear is exposed outside the diaphragm.

9. The method for preparing a pole piece according to claim 8, characterized in that: A flat film for forming a diaphragm is folded in half to form a first film sheet and a second film sheet, wherein the first film sheet and the second film sheet surround the diaphragm in which the chamber is set.

10. The method for preparing a pole piece according to claim 9, characterized in that: A through hole is provided at the bent connection portion between the first diaphragm and the second diaphragm.

11. The method for preparing a pole piece according to claim 9, characterized in that: The edge of the first film sheet located at the opening position and the edge of the second film sheet located at the opening position are bonded or hot-melted to close the opening of the chamber.

12. The method for preparing a pole piece according to claim 11, characterized in that: After the first membrane sheet and the second membrane sheet are connected, the method further includes cutting the first membrane sheet and the second membrane sheet along one side of the connection position to remove excess parts.

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

14. An energy storage device, characterized in that: The battery device as claimed in claim 13 is used to store or provide electrical energy.

15. An electrical device, characterized in that: Comprising the battery device as claimed in claim 13 and / or the energy storage device as claimed in claim 14.

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