Battery monomer, battery device and electric device

Abstract

The embodiment of the utility model provides a battery monomer, a battery device and a power utilization device. The battery cell comprises an electrode assembly, and the electrode assembly comprises a first pole piece and a separator. The first pole piece comprises a first current collector and a first active substance layer, the first active substance layer is arranged on at least one surface of the first current collector in the thickness direction of the first pole piece, the first active substance layer comprises a first main body region and a first thinned region connected with the first main body region, and the separator comprises a body, a first coating layer and a second coating layer, the body is provided with a first surface facing the first pole piece, the first surface is coated with the first coating layer, the side, away from the first surface, of the first coating layer is coated with the second coating layer, and in the thickness direction of the first pole piece, at least one part of the second coating layer is located between the first coating layer and the first thinned area. Wherein the liquid absorption rate of the second coating layer is greater than that of the first coating layer. According to the technical scheme, the reliability of the battery device can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery production, in particular to a battery monomer, a battery device and a power utilization device. BACKGROUND

[0002] Energy saving and emission reduction is the key to the sustainable development of the automobile industry. Electric vehicles have become an important part of the sustainable development of the automobile industry due to their energy saving and environmental protection advantages. For electric vehicles, battery technology is an important factor for their development.

[0003] In the development of battery technology, how to improve the reliability of the battery device is an urgent technical problem to be solved in the battery technology. CONTENT OF THE INVENTION

[0004] The present application provides a battery monomer, a battery device and a power utilization device, which can improve the reliability of the battery device.

[0005] The present application is achieved by the following technical solutions:

[0006] In a first aspect, the present application provides a battery monomer, which comprises an electrode assembly, and the electrode assembly comprises a first pole piece and a separator. The first pole piece comprises a first current collector and a first active material layer, the first active material layer is arranged on at least one surface of the first current collector in the thickness direction of the first pole piece, the first active material layer comprises a first main body area and a first thinning area connected with the first main body area, the first thinning area is located at at least one end of the first main body area in the width direction of the first pole piece, and the thickness of the first thinning area is smaller than the thickness of the first main body area. The separator comprises a body, a first coating layer and a second coating layer, the body has a first surface facing the first pole piece, the first coating layer is coated on the first surface, the second coating layer is coated on the side of the first coating layer away from the first surface, and in the thickness direction of the first pole piece, at least a part of the second coating layer is located between the first coating layer and the first thinning area. The liquid absorption rate of the second coating layer is greater than the liquid absorption rate of the first coating layer.

[0007] The technical scheme of the embodiment of the application reduces the risk of ion precipitation around the bubble by reducing the risk of bubble generation between the first coating layer and the first thinning area in the thickness direction of the first tab. In the process of charging and discharging, the ions move between the first active material layer of the first tab and the separator. Since there is no medium (such as electrolyte) for ion movement in the bubble, the ions cannot directly pass through the bubble and need to bypass the bubble, which increases the number of ions around the bubble. At the same time, the number of electrolyte ions transported in a unit space is limited, thereby increasing the risk of ion precipitation around the bubble. Since the risk of bubble generation between the first coating layer and the first thinning area is reduced, the risk of ion precipitation due to the bubble is reduced, which is prone to increase the internal resistance and the risk of short circuit caused by the ion precipitation. Therefore, reducing the risk of ion precipitation is conducive to improving the reliability of the battery cell and the reliability of the battery device. In addition, electrolyte is the medium for ion movement. Since the liquid absorption rate of the second coating layer is greater than that of the first coating layer, the second coating layer absorbs more electrolyte, which is conducive to reducing the risk of ion precipitation between the second coating layer and the first thinning area.

[0008] In some embodiments, the second coating layer is connected with the first thinning area, and the first coating layer is connected with the first main area.

[0009] The technical scheme of the embodiment of the application further reduces the gap between the first coating layer and the first thinning area by connecting the second coating layer with the first thinning area, which is conducive to reducing the risk of ion precipitation and improving the reliability of the battery device.

[0010] In some embodiments, in the thickness direction of the first tab, the surface of the second coating layer away from the first coating layer is connected with the surface of the first thinning area away from the first current collector.

[0011] The technical scheme of the embodiment of the application further reduces the gap between the first coating layer and the first thinning area by connecting the second coating layer with the first thinning area, which is conducive to reducing the risk of ion precipitation and improving the reliability of the battery device.

[0012] In some embodiments, the thickness of the first thinning area gradually decreases in the direction close to the edge of the first tab; and the thickness of the second coating layer gradually increases in the direction close to the edge of the separator.

[0013] The technical scheme of the embodiment of the present application sets the thickness variation of the second coating layer to match the thickness variation of the first thinning area, so that the second coating layer can be better connected with the first thinning area, further reducing the gap between the first coating layer and the first thinning area, which is beneficial to reduce the risk of ion precipitation and improve the reliability of the battery device.

[0014] In some embodiments, the liquid absorption rate of the second coating layer is 80% to 300%.

[0015] The technical scheme of the embodiment of the present application sets the liquid absorption rate of the second coating layer to meet the above conditions. When the liquid absorption rate of the second coating layer is greater than 80%, the second coating layer absorbs more electrolyte, which is beneficial to reduce the risk of ion precipitation between the second coating layer and the first thinning area. Since the greater the liquid absorption rate, the higher the cost of the material, and the more electrolyte is absorbed, i.e., more electrolyte needs to be injected into the battery monomer, when the liquid absorption rate of the second coating layer is less than 300%, the cost can be saved.

[0016] In some embodiments, the liquid absorption rate of the second coating layer is 220% to 300%.

[0017] The technical scheme of the embodiment of the present application sets the liquid absorption rate of the second coating layer to meet the above conditions, which is beneficial to reduce the risk of ion precipitation between the second coating layer and the first thinning area, and can save costs.

[0018] In some embodiments, the material of the first coating layer and the material of the second coating layer are different.

[0019] The technical scheme of the embodiment of the present application sets the material of the first coating layer and the material of the second coating layer to be different, which is beneficial to realize that the liquid absorption rate of the second coating layer is greater than the liquid absorption rate of the first coating layer, and is beneficial to reduce the risk of ion precipitation between the second coating layer and the first thinning area.

[0020] In some embodiments, the material of the first coating layer and the material of the second coating layer are the same.

[0021] The technical scheme of the embodiment of the present application sets the material of the first coating layer and the material of the second coating layer to be the same, so that the first coating layer and the second coating layer can be coated at the same time, which is beneficial to improve the convenience of processing and improve the production efficiency of the battery device.

[0022] In some embodiments, the material of the second coating layer is one of polyurethane, polyether ester elastic fiber, ultra-high molecular weight polyethylene, epoxy resin, acrylic resin, silicone resin, polystyrene maleic anhydride copolymer, and polyvinylidene fluoride.

[0023] The technical scheme of the embodiment of the application selects one of the above materials as the material of the second coating layer, so that the liquid absorption rate of the second coating layer is relatively large, and the risk of ion precipitation between the second coating layer and the first thinning area is reduced.

[0024] In some embodiments, the material of the second coating layer is polyurethane.

[0025] The technical scheme of the embodiment of the application selects polyurethane as the material of the second coating layer, so that the liquid absorption rate of the second coating layer is relatively large, and the risk of ion precipitation between the second coating layer and the first thinning area is reduced.

[0026] In some embodiments, the number of the first thinning areas is two, and the two first thinning areas are respectively located at two ends of the first main area in the width direction of the first tab.

[0027] The technical scheme of the embodiment of the application reduces the thickness of the first thinning area to less than the thickness of the first main area, that is, the first active material of the first thinning area is less, and the risk of ion precipitation in the first thinning area is reduced. By arranging the first thinning area at two ends of the first main area in the width direction of the first tab, the risk of ion precipitation in the first tab is further reduced, and the reliability of the battery device is improved.

[0028] In some embodiments, the electrode assembly further includes a second tab, the first tab and the second tab are opposite in polarity, and the separator is arranged between the first tab and the second tab. The second tab includes a second current collector and a second active material layer, the second active material layer is arranged on at least one surface of the second current collector in the thickness direction, the second active material layer includes a second main area and a second thinning area connected to the second main area, the second thinning area is located at at least one end of the second main area in the width direction of the second tab, and the thickness of the second thinning area is less than the thickness of the second main area. In the projection plane perpendicular to the thickness direction of the first tab, the orthographic projection of the first thinning area at least partially overlaps the orthographic projection of the second thinning area.

[0029] The technical scheme of the embodiment of the application arranges the first tab and the second tab opposite in polarity to realize the charging and discharging of the battery monomer, and arranges the separator between the first tab and the second tab to reduce the risk of contact between the first tab and the second tab and thus causing short circuit.

[0030] In some embodiments, the separator further includes a third coating layer and a fourth coating layer, the body has a second surface facing the second tab, the third coating layer is coated on the second surface, the fourth coating layer is coated on a side of the third coating layer away from the second surface, and in the thickness direction of the second tab, at least a part of the fourth coating layer is located between the third coating layer and the second thinning area.

[0031] The technical scheme of the embodiment of the present application reduces the gap between the third coating layer and the second thinning area in the thickness direction of the second tab, thereby reducing the risk of ion precipitation between the third coating layer and the second thinning area, and facilitating the reduction of the risk of ion precipitation and the improvement of the reliability of the battery device.

[0032] In some embodiments, the liquid absorption rate of the fourth coating layer is greater than the liquid absorption rate of the third coating layer.

[0033] The technical scheme of the embodiment of the present application reduces the gap between the third coating layer and the second thinning area in the thickness direction of the second tab, thereby reducing the risk of ion precipitation between the third coating layer and the second thinning area, and facilitating the reduction of the risk of ion precipitation and the improvement of the reliability of the battery device.

[0034] In some embodiments, the fourth coating layer is connected with the second thinning area, and the third coating layer is connected with the second main area.

[0035] The technical scheme of the embodiment of the present application reduces the gap between the third coating layer and the second thinning area in the thickness direction of the second tab, thereby reducing the risk of ion precipitation between the third coating layer and the second thinning area, and facilitating the reduction of the risk of ion precipitation and the improvement of the reliability of the battery device.

[0036] In some embodiments, the first tab is a negative tab, the second tab is a positive tab, and in the projection plane perpendicular to the thickness direction of the first tab, the positive projection of the first active material layer covers the positive projection of the second active material layer, and the positive projection of the second coating layer covers the positive projection of the fourth coating layer.

[0037] The technical scheme of the embodiment of the present application reduces the gap between the third coating layer and the second thinning area in the thickness direction of the second tab, thereby reducing the risk of ion precipitation between the third coating layer and the second thinning area, and facilitating the reduction of the risk of ion precipitation and the improvement of the reliability of the battery device.

[0038] In some embodiments, the electrode assembly is of a winding type.

[0039] The technical scheme of the embodiment of the present application reduces the gap between the third coating layer and the second thinning area in the thickness direction of the second tab, thereby reducing the risk of ion precipitation between the third coating layer and the second thinning area, and facilitating the reduction of the risk of ion precipitation and the improvement of the reliability of the battery device.

[0040] In the second aspect, the present application provides a battery device comprising the battery cell according to any one of the embodiments of the first aspect.

[0041] In a third aspect, the application also provides a power consuming device comprising the battery cell of any one of the first aspect or the battery device of any one of the second aspect, the battery cell or the battery device being configured to provide power for the power consuming device.

[0042] Additional aspects and advantages of the application will be made apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some of the embodiments of the application, and therefore should not be considered as a limitation to the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0044] Figure 1 A structural schematic diagram of a vehicle provided by some embodiments of the application;

[0045] Figure 2 A structural exploded view of a battery device provided by some embodiments of the application;

[0046] Figure 3 A structural exploded view of a battery cell provided by some embodiments of the application;

[0047] Figure 4 A structural schematic diagram of an electrode assembly provided by some embodiments of the application;

[0048] Figure 5 A cooperation schematic diagram of a first pole piece and a separator provided by some embodiments of the application;

[0049] Figure 6 An exploded schematic diagram of a first pole piece and a separator provided by some embodiments of the application;

[0050] Figure 7 A cooperation schematic diagram of a second pole piece and a separator provided by some embodiments of the application;

[0051] Figure 8 An exploded schematic diagram of a second pole piece and a separator provided by some embodiments of the application.

[0052] Icon: 1 - battery cell; 10 - electrode assembly; 11 - first tab; 111 - first current collector; 112 - first active material layer; 1121 - first main region; 1122 - first thinned region; 12 - separator; 121 - body; 1211 - first surface; 1212 - second surface; 122 - first coating layer; 123 - second coating layer; 124 - third coating layer; 125 - fourth coating layer; 13 - second tab; 131 - second current collector; 132 - second active material layer; 1321 - second main region; 1322 - second thinned region; 20 - case; 21 - housing; 22 - end cap; 30 - electrode terminal; 100 - battery device; 110 - box; 120 - first box; 130 - second box; 1000 - vehicle; 1100 - controller; 1200 - motor; X - width direction of the first tab; Y - thickness direction of the first tab. DETAILED DESCRIPTION

[0053] In order to make the objects, technical solutions, and advantages of the embodiments of the present application clearer, the following will be combined with the accompanying drawings for the embodiments of the present application to make a clear and complete description of the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0054] Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs; the terms used in the present application are only for the purpose of describing the specific embodiments and are not intended to limit the present application; the terms "include" and "have" and any variations thereof in the specification and claims of the present application and the above description of drawings are intended to cover not exclusive inclusion. The terms "first", "second", and the like in the specification and claims of the present application and the above description of drawings are used to distinguish different objects, rather than to describe a particular order or primary and secondary relationship.

[0055] In the present application, the phrase "embodiment" means that the specific features, structures, or characteristics described in conjunction with the embodiment can be included in at least one embodiment of the present application. The appearance of this phrase at various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment to other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in the present application can be combined with other embodiments.

[0056] In the description of the application, it should be explained that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting", "attachment" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0057] The term "and / or" in this application is only to describe the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B can mean that A exists alone, A and B exist together, and B exists alone. In addition, the character " / " in this application generally represents that the front and rear associated objects have an "or" relationship.

[0058] "Multiple" appearing in this application refers to two or more (including two), and similarly, "multiple groups" refers to two or more groups (including two groups), and "multiple pieces" refers to two or more pieces (including two pieces).

[0059] The battery device mentioned in the embodiments of the application can include one or more battery cell assemblies for providing voltage and capacity. The battery cell assembly can include a plurality of battery cells connected in series, parallel or mixed connection through a busbar component.

[0060] In some embodiments, the battery cell assembly is usually formed by arranging a plurality of battery cells; as an example, the battery cell assembly can be a battery module, which is formed by arranging and fixing a plurality of battery cells into an independent module. As an example, the battery module can be formed by bundling a plurality of battery cells with a cable tie.

[0061] In some embodiments, the battery device can be a battery pack, which includes a box body and one or more battery cell assemblies, and the battery cell assemblies are accommodated in the box body.

[0062] As an example, the battery cell assembly can be a battery module, and the battery cell assembly can be accommodated in the box body by fixing the battery module in the box body.

[0063] As an example, the battery cell assembly can also be accommodated in the box body by directly fixing a plurality of battery cells in the box body.

[0064] As an example, the box body can include a first box body and a second box body. The first box body and the second box body are buckled to form a closed space inside the box body to accommodate the battery cell assembly. Here, closed means covered or closed, which can be sealed or unsealed. The first box body can be a top cover or a bottom plate.

[0065] As an example, the case can include a top cover, a frame, and a bottom plate. The top cover and the bottom plate are respectively connected with the frame, so that an enclosed space is formed inside the case to accommodate the battery cell assembly.

[0066] As an example, the case can be part of a chassis structure of a vehicle. For example, the top cover of the case can be at least part of a floor of the vehicle, or the frame of the case can be at least part of a cross beam and a longitudinal beam of the vehicle.

[0067] In embodiments of the present application, the battery cell can be a secondary battery, which refers to a battery cell that can be used continuously by activating active materials through charging after the battery cell is discharged.

[0068] The battery cell can be, but is not limited to, a lithium ion battery, a sodium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium sulfur battery, a magnesium ion battery, a nickel-hydrogen battery, a nickel-cadmium battery, a lead-acid battery, etc.

[0069] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes, and the prismatic battery cell includes a square battery cell.

[0070] The battery cell generally includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During charging and discharging of the battery cell, active ions (e.g., lithium ions) are inserted and extracted between the positive electrode and the negative electrode. The separator is disposed between the positive electrode and the negative electrode, and can prevent the positive and negative electrodes from short-circuiting while allowing the active ions to pass through.

[0071] In some embodiments, the positive electrode can be a positive electrode tab, which can include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0072] As an example, the positive electrode current collector has two opposite surfaces in the thickness direction thereof, and the positive electrode active material is disposed on either one or both of the opposite surfaces of the positive electrode current collector.

[0073] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, aluminum with silver plating on the surface, stainless steel with silver plating on the surface, stainless steel, copper, aluminum, nickel, a carbon electrode, carbon, nickel, or titanium, etc. can be used. The composite current collector can include a high molecular material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a high molecular material base material (such as a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0074] As an example, the positive electrode active material can include at least one of lithium-containing phosphates, lithium transition metal oxides, and modified compounds of each thereof. However, the present application is not limited to these materials, and other conventional materials that can be used as a battery positive electrode active material can also be used.

[0075] In some embodiments, the negative electrode can be a negative electrode tab, and the negative electrode tab can include a negative electrode current collector.

[0076] As an example, the negative electrode current collector can employ a metal foil or a composite current collector. For example, as a metal foil, aluminum with a silver plating surface treatment, stainless steel with a silver plating surface treatment, stainless steel, copper, aluminum, nickel, a carbon electrode, and the like with carbon, nickel, or titanium can be employed.

[0077] In some embodiments, the negative electrode current collector has two surfaces opposite in the thickness direction thereof, and the negative electrode active material is disposed on either one or both of the two surfaces of the negative electrode current collector.

[0078] As an example, the negative electrode active material can employ a negative electrode active material for a battery known in the art. As an example, the negative electrode active material can include at least one of artificial graphite, natural graphite, soft carbon, hard carbon, a silicon-based material, a tin-based material, lithium titanate, and the like. The silicon-based material can be selected from at least one of elemental silicon, a silicon oxide compound, a silicon-carbon composite, a silicon-nitrogen composite, and a silicon alloy. The tin-based material can be selected from at least one of elemental tin, a tin oxide compound, and a tin alloy. However, the present application is not limited to these materials, and other conventional materials that can be used as a battery negative electrode active material can also be used. These negative electrode active materials can be used alone or in combination of two or more.

[0079] In some embodiments, the separator is a separator film. The present application does not have a particular limitation on the type of separator film, and any known porous structure separator film having good chemical stability and mechanical stability can be used.

[0080] As an example, the main material of the separator film can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride, and ceramic. The separator film can be a single layer film or a multi-layer composite film, and is not particularly limited. When the separator film is a multi-layer composite film, the materials of the respective layers can be the same or different, and are not particularly limited. The separator film can be a separate member located between the positive and negative electrodes, or can be attached to the surface of the positive and negative electrodes.

[0081] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, and functions to transport ions and separate the positive and negative electrodes.

[0082] In some embodiments, the electrode assembly can have a roll structure. The positive electrode tab and the negative electrode tab are rolled to have the roll structure.

[0083] At present, from the development of market situation, the battery has been widely used in electric bicycles, electric motorcycles, electric vehicles and other electric vehicles, electric tools, unmanned aerial vehicles, energy storage equipment and other fields. With the continuous expansion of the field of battery, the demand of its market is also increasing.

[0084] The development of battery technology needs to consider many design factors, such as energy density, cycle life, discharge capacity, charge-discharge rate and other performance parameters. In addition, with the change of environmental conditions and / or internal conditions of the battery, the reliability of the battery device is also one of the key factors to be considered.

[0085] At present, the electrode assembly includes a first electrode sheet, a separator and a second electrode sheet, the polarities of the first electrode sheet and the second electrode sheet are opposite, the separator is arranged between the first electrode sheet and the second electrode sheet, and the first electrode sheet, the separator and the second electrode sheet are formed into an electrode assembly by winding or stacking. In order to reduce the risk of edge stress concentration of the first electrode sheet during winding or stacking, which leads to damage of the electrode sheet, and reduce the risk of insufficient infiltration of electrolyte in the first electrode sheet, which leads to failure of ion transport, a part of the area of the first electrode sheet is usually provided with a thinning area, so that the active material layer content of the thinning area is less than that of other areas.

[0086] Usually, the relative position between the first electrode sheet and the separator remains unchanged, and the active material layer of the first electrode sheet contacts the separator. However, after the thinning area is arranged, a gap is generated between the thinning area and the separator. During the use of the battery device, the gap between the thinning area and the separator is easy to produce bubbles. When the first electrode sheet and the second electrode sheet transfer ions, the ions move through the electrolyte as a medium. The space of the generated bubbles does not have electrolyte, so that when the ions move to contact the bubbles, the ions cannot directly pass through the bubbles and need to move around the bubbles, which increases the ions around the bubbles. At the same time, the amount of electrolyte in the unit space for transporting ions is limited, so that the risk of ion precipitation around the bubbles increases. Ion precipitation is easy to cause the internal resistance of the battery device to increase, and the precipitated ions have the risk of piercing the separator to cause short circuit, which affects the reliability of the battery device.

[0087] To reduce the risk of bubbles occurring between the first electrode tab and the separator, causing ions to be precipitated and affecting the reliability of the battery device, the application provides a battery monomer, which comprises an electrode assembly, and the electrode assembly comprises a first electrode tab and a separator. The first electrode tab comprises a first current collector and a first active material layer, and the first active material layer is arranged on at least one surface of the first current collector in the thickness direction of the first electrode tab. The first active material layer comprises a first main area and a first thinned area connected to the first main area. The first thinned area is located at at least one end of the first main area in the width direction of the first electrode tab, and the thickness of the first thinned area is less than that of the first main area. The separator comprises a body, a first coating layer and a second coating layer. The body has a first surface facing the first electrode tab. The first coating layer is coated on the first surface. The second coating layer is coated on the side of the first coating layer away from the first surface. In the thickness direction of the first electrode tab, at least a part of the second coating layer is located between the first coating layer and the first thinned area. The liquid absorption rate of the second coating layer is greater than that of the first coating layer.

[0088] The technical scheme of the embodiment of the application reduces the risk of bubbles occurring between the first coating layer and the first thinned area in the thickness direction of the first electrode tab by arranging the second coating layer between the first coating layer and the first thinned area, thereby reducing the risk of bubbles occurring between the first coating layer and the first thinned area. At the same time, in the process of charging and discharging, ions will move between the first active material layer of the first electrode tab and the separator. Since there is no medium (such as electrolyte) for ion movement in the bubble, the ions cannot directly pass through the bubble and need to move around the bubble, resulting in an increase in the number of ions around the bubble. At the same time, the amount of electrolyte in a unit space for transporting ions is limited, thereby increasing the risk of ion precipitation around the bubble. Since the risk of bubbles occurring between the first coating layer and the first thinned area is reduced, the risk of ion precipitation around the bubble due to the bubbles is reduced. Ion precipitation easily leads to an increase in internal resistance and the risk of short circuit caused by the precipitated ions piercing the separator. Therefore, reducing the risk of ion precipitation helps to improve the reliability of the battery monomer and the reliability of the battery device. In addition, electrolyte is the medium for ion movement. Since the liquid absorption rate of the second coating layer is greater than that of the first coating layer, the second coating layer absorbs more electrolyte, thereby reducing the risk of ion precipitation between the second coating layer and the first thinned area.

[0089] The battery disclosed in the embodiment of the application can be used in, but is not limited to, an electric device such as a vehicle, a ship or an aircraft. The power supply system of the electric device can be composed of the battery disclosed in the application.

[0090] The embodiments of the present application provide a power consumption device using a battery device as a power supply. The power consumption device can be, but is not limited to, a mobile phone, a tablet computer, a notebook computer, an electric toy, an electric tool, an electric bicycle, an electric motorcycle, an electric vehicle, a ship, a spacecraft and the like. The electric toy can include a fixed or mobile electric toy, such as a game console, an electric vehicle toy, an electric ship toy and an electric aircraft toy and the like. The spacecraft can include an airplane, a rocket, a space shuttle and a spacecraft and the like.

[0091] The following embodiments are described by taking a power consumption device of the embodiments of the present application as a vehicle for example for convenience of description.

[0092] Please refer to Figure 1 , Figure 1 The structure schematic diagram of the vehicle provided by some embodiments of the present application is shown. The vehicle 1000 can be a fuel automobile, a gas automobile or a new energy automobile. The new energy automobile can be a pure electric vehicle, a hybrid electric vehicle or a range extended vehicle and the like. The vehicle 1000 is internally provided with a battery device 100. The battery device 100 can be arranged at the bottom, the head or the tail of the vehicle 1000. The battery device 100 can be used for power supply of the vehicle 1000. For example, the battery device 100 can be used as an operating power supply of the vehicle 1000, and is used for the circuit system of the vehicle 1000, such as the working power demand of the vehicle 1000 during starting, navigation and running.

[0093] The vehicle 1000 can further include a controller 1100 and a motor 1200. The controller 1100 is used to control the battery device 100 to supply power to the motor 1200, such as the working power demand of the vehicle 1000 during starting, navigation and running.

[0094] In some embodiments of the present application, the battery device 100 can not only be used as an operating power supply of the vehicle 1000, but also be used as a driving power supply of the vehicle 1000, to replace or partially replace fuel or natural gas to provide driving power for the vehicle 1000.

[0095] Please refer to Figure 2 , Figure 2A structural exploded view of a battery device is provided for some embodiments of the present application. The battery device 100 can further include a case 110 in which the battery cell 1 is accommodated. The case 110 is configured to provide an accommodation space for the battery cell 1, and can have various structures. In some embodiments, the case 110 can include a first case 120 and a second case 130. The first case 120 and the second case 130 are coupled to each other to define an accommodation space for the battery cell 1. The second case 130 can be a hollow structure with one open end, and the first case 120 can be a plate structure. The first case 120 is coupled to the open end of the second case 130 to define the accommodation space together with the second case 130. Alternatively, the first case 120 and the second case 130 can each be a hollow structure with one open end, and the open end of the first case 120 is coupled to the open end of the second case 130.

[0096] In the battery device 100, the battery cell 1 can be multiple. The multiple battery cells 1 can be connected in series, in parallel, or in a mixed connection. The mixed connection means that the multiple battery cells 1 are connected in series and in parallel. The multiple battery cells 1 can be directly connected in series, in parallel, or in a mixed connection, and the multiple battery cells 1 are accommodated in the case 110. Alternatively, the multiple battery cells 1 can be connected in series, in parallel, or in a mixed connection to form a battery module, and the multiple battery modules are connected in series, in parallel, or in a mixed connection to form a whole, which is accommodated in the case 110. The battery device 100 can further include other structures. For example, the battery device 100 can further include a busbar component for electrically connecting the multiple battery cells 1.

[0097] The battery cell 1 can be a secondary battery or a primary battery. The battery cell 1 can be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto.

[0098] Please refer to Figure 3 , Figure 3 A structural exploded view of a battery cell is provided for some embodiments of the present application. As shown in Figure 3 , the battery cell 1 includes a housing 20, an electrode assembly 10, and an electrode terminal 30. The housing 20 includes a case 21 having an opening and an end cap 22 closing the opening to isolate an internal environment of the battery cell 1 from an external environment.

[0099] The shell 21 is a component for fitting the end cover 22 to form an internal environment of the battery cell 1, wherein the formed internal environment can be used to accommodate the electrode assembly 10, electrolyte and other components. The shell 21 and the end cover 22 can be independent components. The shell 21 can be of various shapes and sizes. Specifically, the shape of the shell 21 can be determined according to the specific shape and size of the electrode assembly 10. The material of the shell 21 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.

[0100] The end cover 22 refers to a component that covers the opening of the shell 21 to isolate the internal environment of the battery cell 1 from the external environment. Without limitation, the shape of the end cover 22 can be adapted to the shape of the shell 21 to fit the shell 21. Alternatively, the end cover 22 can be made of a material with certain hardness and strength (such as aluminum alloy), so that the end cover 22 is not easily deformed when subjected to extrusion collision, so that the battery cell 1 can have higher structural strength, and the reliability can also be improved. The end cover 22 can be provided with functional components such as the electrode terminal 30. The electrode terminal 30 can be used to electrically connect with the electrode assembly 10 for outputting or inputting the electrical energy of the battery cell 1. The material of the end cover 22 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which are not specially limited in the embodiments of the present application. In some embodiments, an insulating structure can also be provided on the inner side of the end cover 22, which can be used to isolate the electrical connection components in the shell 21 from the end cover 22 to reduce the risk of short circuit. Exemplarily, the insulating structure can be plastic, rubber, etc.

[0101] Please refer to Figure 4 , Figure 4 The structural schematic diagram of the electrode assembly provided by some embodiments of the present application is shown in the figure. As shown in the figure, the electrode assembly 10 is a component in which electrochemical reactions occur in the battery cell 1. One or more electrode assemblies 10 can be contained in the shell 21. The electrode assembly 10 is mainly formed by winding the first electrode sheet 11 and the second electrode sheet 13, and an insulating member 12 is usually provided between the first electrode sheet 11 and the second electrode sheet 13 to separate the first electrode sheet 11 and the second electrode sheet 13 to reduce the risk of internal short circuit of the first electrode sheet 11 and the second electrode sheet 13. The parts of the first electrode sheet 11 and the second electrode sheet 13 with active material constitute the main body part of the electrode assembly 10, and the parts of the first electrode sheet 11 and the second electrode sheet 13 without active material each constitute a tab. Among them, the first electrode sheet 11 can be a positive electrode sheet, and the second electrode sheet 13 can be a negative electrode sheet. The positive electrode tab and the negative electrode tab can be located at one end of the main body part or at two ends of the main body part respectively. In the charging and discharging process of the battery device 100, the positive active material and the negative active material react with the electrolyte, and the tabs are connected with the electrode terminal to form a current loop.

[0102] Please refer to Figure 4Referring to Figure 5 and Figure 6 , Figure 5 A matching diagram of the first tab and the separator provided by some embodiments of the present application, Figure 6 An exploded diagram of the first tab and the separator provided by some embodiments of the present application. The first thinned area and the first main area are separated by a dashed line. Some embodiments of the present application provide a battery monomer 1, which includes an electrode assembly 10, and the electrode assembly 10 includes a first tab 11 and a separator 12. The first tab 11 includes a first current collector 111 and a first active material layer 112, the first active material layer 112 is arranged on at least one surface of the first current collector 111 in the thickness direction Y of the first tab, the first active material layer 112 includes a first main area 1121 and a first thinned area 1122 connected to the first main area 1121, the first thinned area 1122 is located at at least one end of the first main area 1121 in the width direction X of the first tab, and the thickness of the first thinned area 1122 is less than the thickness of the first main area 1121. The separator 12 includes a body 121, a first coating layer 122 and a second coating layer 123, the body 121 has a first surface 1211 facing the first tab 11, the first coating layer 122 is coated on the first surface 1211, and the second coating layer 123 is coated on the side of the first coating layer 122 away from the first surface 1211, and in the thickness direction Y of the first tab, at least a part of the second coating layer 123 is located between the first coating layer 122 and the first thinned area 1122. Among them, the liquid absorption rate of the second coating layer 123 is greater than that of the first coating layer 122.

[0103] In some embodiments, the battery monomer 1 can include a shell 20 and an electrode assembly 10, and the electrode assembly 10 can be accommodated in the shell 20.

[0104] In some embodiments, the thickness direction of the first tab can be represented by the direction indicated by the letter Y in the figure.

[0105] In some embodiments, the thickness direction Y of the first tab can be parallel to the thickness direction of the separator 12.

[0106] In some embodiments, the first active material layer 112 can be arranged on the surface of the first current collector 111 facing the separator 12 in the thickness direction Y of the first tab.

[0107] In some embodiments, the first active material layer 112 can be arranged on both surfaces of the first current collector 111 in the thickness direction Y of the first tab.

[0108] In some embodiments, the first tab 11 can be a positive tab, and correspondingly, the first active material layer 112 can be a positive active material layer.

[0109] In some embodiments, the first tab 11 can be a negative electrode tab, and the first active material layer 112 can be a negative electrode active material layer.

[0110] In some embodiments, both surfaces of the first current collector 111 in the thickness direction Y of the first tab can be provided with the first active material layer 112.

[0111] The first active material layer 112 can include a first main area 1121 and a first thinned area 1122, and the thickness of the first main area 1121 can be greater than the thickness of the first thinned area 1122 in the thickness direction Y of the first tab.

[0112] In some embodiments, the thickness of the first main area 1121 on both surfaces of the first current collector 111 can be the same or different.

[0113] In some embodiments, the thickness of the first thinned area 1122 on both surfaces of the first current collector 111 can be the same or different.

[0114] In some embodiments, during the processing of the first tab 11, the first active material can be uniformly coated on the surface of the first current collector 111 to form the first active material layer 112. After the coating is completed, the first active material in the partial area, which is the first thinned area 1122, is thinned, so as to divide the first active material layer 112 into the first main area 1121 and the first thinned area 1122.

[0115] In some embodiments, the width direction of the first tab can be represented by the direction indicated by the letter X in the figure.

[0116] In some embodiments, the width direction X of the first tab and the thickness direction Y of the first tab can be perpendicular.

[0117] In some embodiments, the width direction X of the first tab and the width direction of the separator 12 can be parallel.

[0118] In some embodiments, in the width direction X of the first tab, the number of the first thinned areas 1122 can be one, and the first thinned area 1122 can be connected to one end of the first main area 1121; or the number of the first thinned areas 1122 can be two, and the two first thinned areas 1122 can be respectively connected to two ends of the first main area 1121.

[0119] In some embodiments, in the thickness direction Y of the first tab, the separator 12 can include a body 121, a first coating layer 122 and a second coating layer 123 arranged in sequence, and the surface of the body 121 facing the first tab 11 is a first surface 1211.

[0120] The first coating layer 122 can be coated on the first surface 1211, so that the first coating layer 122 is located between the first main body area 1121 and the body 121. In some embodiments, a part of the first coating layer 122 can be located between the first main body area 1121 and the body 121, and another part of the first coating layer 122 can be located between the first thinning area 1122 and the body 121.

[0121] The second coating layer 123 is coated on the surface of the first coating layer 122 away from the first surface 1211, and the second coating layer 123 is located between the first coating layer 122 and the first thinning area 1122. That is, the second coating layer 123 is located at at least one end of the first coating layer 122 in the width direction X of the first pole piece, and the first pole piece 11 and the spacer 12 are projected on the projection surface perpendicular to the thickness direction Y of the first pole piece as the projection direction, to obtain the orthographic projection of the first pole piece 11 and the orthographic projection of the spacer 12, wherein the orthographic projection of the second coating layer 123 covers the orthographic projection of the first thinning area 1122.

[0122] In some embodiments, the material of the first coating layer 122 can be a ceramic coating material, such as silicon oxide, and can also be a polymer coating material, such as polyvinylidene fluoride.

[0123] In some embodiments, the material of the first coating layer 122 can be polyvinylidene fluoride, so as to improve the structural strength of the spacer 12 and improve the performance of the spacer 12 to absorb electrolyte, and facilitate the movement of ions through the spacer 12.

[0124] In some embodiments, the material of the second coating layer 123 can be polyurethane, polyether ester elastic fiber, ultra-high molecular weight polyethylene, epoxy resin, acrylic resin, silicone resin, polystyrene maleic anhydride copolymer, polyvinylidene fluoride, etc.

[0125] In some embodiments, the material of the second coating layer 123 can be polyurethane, so as to improve the structural strength of the spacer 12 and improve the performance of the spacer 12 to absorb electrolyte, and facilitate the movement of ions through the spacer 12.

[0126] Taking the electrode assembly 10 in a wound structure as an example, the width direction X of the first pole piece can be parallel to the direction of gravity, and the first thinning area 1122 can be located above the first main body area 1121. Due to the action of gravity, the electrolyte in the battery monomer 1 infiltrates downward, resulting in that there is less electrolyte in the area corresponding to the first thinning area 1122, that is, there is less medium for the movement of ions, thereby increasing the risk of ion precipitation. In some embodiments, the liquid absorption rate of the second coating layer 123 can be greater than the liquid absorption rate of the first coating layer 122, so that the second coating layer 123 can absorb more electrolyte, thereby increasing the amount of electrolyte in the area corresponding to the first thinning area 1122, and reducing the risk of ion precipitation.

[0127] In some embodiments, the method of obtaining the liquid absorption rate of the second coating layer 123 can be as follows:

[0128] A certain mass (such as A) of the second coating layer 123 is taken out, the second coating layer 123 is immersed in a liquid (such as an electrolyte), and after a period of time (such as one hour), the second coating layer 123 is allowed to absorb the liquid to a saturated state. The second coating layer 123 is taken out, and the taken-out second coating layer 123 is weighed to obtain the mass B of the second coating layer 123, and the value of the liquid absorption rate is (B-A) / A.

[0129] Similarly, the method of obtaining the liquid absorption rate of the first coating layer 122 can be as follows:

[0130] A certain mass (such as A) of the first coating layer 122 is taken out, the first coating layer 122 is immersed in a liquid (such as an electrolyte), and after a period of time (such as one hour), the first coating layer 122 is allowed to absorb the liquid to a saturated state. The first coating layer 122 is taken out, and the taken-out first coating layer 122 is weighed to obtain the mass B of the first coating layer 122, and the value of the liquid absorption rate is (B-A) / A.

[0131] The technical scheme of the embodiments of the present application reduces the risk of bubbles generated between the first coating layer 122 and the first thinning area 1122 by arranging the second coating layer 123 between the first coating layer 122 and the first thinning area 1122 in the thickness direction Y of the first pole piece, thereby reducing the risk of bubbles generated between the first coating layer 122 and the first thinning area 1122. During charging and discharging, ions move between the first active material layer 112 of the first pole piece 11 and the separator 12. Since there is no medium (such as electrolyte) for ion movement in the bubble, ions cannot directly pass through the bubble and need to bypass the bubble, which increases the number of ions around the bubble. The amount of electrolyte in a unit space is limited, which increases the risk of ion precipitation around the bubble. Since the risk of bubbles generated between the first coating layer 122 and the first thinning area 1122 is reduced, the risk of ion precipitation around the bubble due to the bubbles is reduced, which is prone to increase the internal resistance and the risk of short circuit caused by the precipitated ions piercing the separator 12. Therefore, reducing the risk of ion precipitation improves the reliability of the battery monomer 1 and the reliability of the battery device 100. In addition, electrolyte is the medium for ion movement. Since the liquid absorption rate of the second coating layer 123 is greater than that of the first coating layer 122, the second coating layer 123 absorbs more electrolyte, which reduces the risk of ion precipitation between the second coating layer 123 and the first thinning area 1122.

[0132] Please refer to Figure 5 andFigure 6 In some embodiments, the second coating layer 123 is connected with the first thinned area 1122, and the first coating layer 122 is connected with the first main body area 1121.

[0133] In some embodiments, at least part of the second coating layer 123 can be connected with the first thinned area 1122 in a manner of being attached.

[0134] In some embodiments, the first pole piece 11 and the spacer 12 are projected on a projection plane perpendicular to the thickness direction Y of the first pole piece 11 in the thickness direction Y of the first pole piece as the projection direction, to obtain the orthographic projection of the first pole piece 11 and the orthographic projection of the spacer 12, the orthographic projection of the second coating layer 123 can overlap the orthographic projection of the first thinned area 1122, and the second coating layer 123 can be connected with the first thinned area 1122 in a manner of being attached.

[0135] Alternatively, part of the second coating layer 123 is connected with part of the first thinned area 1122 in a manner of being attached, and another part of the second coating layer 123 is arranged apart from another part of the first thinned area 1122.

[0136] In some embodiments, in the thickness direction Y of the first pole piece, part of the surface of the first coating layer 122 away from the body 121 is provided with the second coating layer 123, and another part is connected with the first main body area 1121.

[0137] The technical scheme of the embodiments of the present application further reduces the gap between the first coating layer 122 and the first thinned area 1122 by connecting the second coating layer 123 with the first thinned area 1122, which is conducive to reducing the risk of ion precipitation and improving the reliability of the battery device 100.

[0138] Please refer to Figure 5 and Figure 6 In some embodiments, in the thickness direction Y of the first pole piece, the surface of the second coating layer 123 away from the first coating layer 122 is connected with the surface of the first thinned area 1122 away from the first current collector 111 in a manner of being attached.

[0139] In some embodiments, the surface of the second coating layer 123 away from the first coating layer 122 can be partially connected with the surface of the first thinned area 1122 away from the first current collector 111 in a manner of being attached.

[0140] In some embodiments, the surface of the second coating layer 123 away from the first coating layer 122 can be fully connected with the surface of the first thinned area 1122 away from the first current collector 111 in a manner of being attached.

[0141] The technical scheme of the embodiment of the present application further reduces the gap between the first coating layer 122 and the first thinning area 1122 by connecting the second coating layer 123 and the first thinning area 1122, which is conducive to reducing the risk of ion precipitation and improving the reliability of the battery device 100.

[0142] Please refer to Figure 5 and Figure 6 In some embodiments, the thickness of the first thinning area 1122 gradually decreases in the direction close to the edge of the first pole piece 11, and the thickness of the second coating layer 123 gradually increases in the direction close to the edge of the separator 12.

[0143] In some embodiments, the direction close to the edge of the first pole piece 11 can be parallel to the width direction X of the first pole piece.

[0144] In some embodiments, the direction close to the edge of the separator 12 can be parallel to the width direction X of the first pole piece.

[0145] In some embodiments, the thickness of the first thinning area 1122 can be the size of the first thinning area 1122 in the thickness direction Y of the first pole piece.

[0146] In some embodiments, the thickness of the second coating layer 123 can be the thickness of the second coating layer 123 in the thickness direction Y of the first pole piece.

[0147] In some embodiments, the thickness of the first thinning area 1122 gradually decreases in the direction close to the edge of the first pole piece 11, that is, the direction from the first main body area 1121 to the first thinning area 1122. Similarly, the thickness of the second coating layer 123 gradually increases in the direction close to the edge of the separator 12, so that the first thinning area 1122 and the second coating layer 123 are connected.

[0148] The technical scheme of the embodiment of the present application sets the thickness variation of the second coating layer 123 to match the thickness variation of the first thinning area 1122, so that the second coating layer 123 can be better connected with the first thinning area 1122, further reducing the gap between the first coating layer 122 and the first thinning area 1122, which is conducive to reducing the risk of ion precipitation and improving the reliability of the battery device 100.

[0149] In some embodiments, the liquid absorption rate of the second coating layer 123 is 80% to 300%.

[0150] In some embodiments, the liquid absorption rate of the second coating layer 123 meets the above condition, and the liquid absorption rate of the second coating layer 123 can be any one of 80%, 100%, 150%, 200%, 250%, 300% or a value between any two of them.

[0151] In some embodiments, the second coating layer 123 is made of different materials, and the corresponding liquid absorption rate changes.

[0152] In some embodiments, the same material is used, and the proportion of the material in the coating slurry is different when the coating slurry is configured, and the porosity of the second coating layer 123 obtained after coating changes, and the liquid absorption rate is also different.

[0153] In some embodiments, the greater the liquid absorption rate of the second coating layer 123, the stronger the ability to absorb electrolyte.

[0154] The technical scheme of the embodiment of the application, the liquid absorption rate of the second coating layer 123 meets the above conditions, when the liquid absorption rate of the second coating layer 123 is greater than 80%, the second coating layer 123 absorbs more electrolyte, which is beneficial to reduce the risk of ion precipitation between the second coating layer 123 and the first thinning area 1122; because the greater the liquid absorption rate, the higher the cost of the material, and the more electrolyte absorbed, that is, more electrolyte needs to be injected into the battery monomer 1, when the liquid absorption rate of the second coating layer 123 is less than 300%, the cost can be saved.

[0155] In some embodiments, the liquid absorption rate of the second coating layer 123 is 220% to 300%.

[0156] In some embodiments, the liquid absorption rate of the second coating layer 123 meets the above conditions, and the liquid absorption rate of the second coating layer 123 can be any one of 220%, 230%, 240%, 250%, 260%, 270%, 280%, 290%, 300% or a value between any two values.

[0157] The technical scheme of the embodiment of the application, the liquid absorption rate of the second coating layer 123 meets the above conditions, which is beneficial to reduce the risk of ion precipitation between the second coating layer 123 and the first thinning area 1122, and can save costs.

[0158] In some embodiments, the material of the first coating layer 122 and the material of the second coating layer 123 are different.

[0159] In some embodiments, the material of the first coating layer 122 and the material of the second coating layer 123 can be different, for example, the material of the first coating layer 122 can be polyvinylidene fluoride.

[0160] In some embodiments, the material of the second coating layer 123 can be polyurethane, polyether ester elastic fiber, ultra-high molecular weight polyethylene, epoxy resin, acrylic resin, silicone resin, polystyrene maleic anhydride copolymer, polyvinylidene fluoride, etc.

[0161] In some embodiments, the first coating layer 122 can be coated first, and then the second coating layer 123 can be coated during the processing of the separator 12.

[0162] The technical solution of the embodiments of the present application sets the material of the first coating layer 122 and the material of the second coating layer 123 as different materials, which is conducive to realizing that the liquid absorption rate of the second coating layer 123 is greater than the liquid absorption rate of the first coating layer 122, and is conducive to reducing the risk of ion precipitation between the second coating layer 123 and the first thinning area 1122.

[0163] In some embodiments, the material of the first coating layer 122 and the material of the second coating layer 123 are the same.

[0164] In some embodiments, the material of the first coating layer 122 and the material of the second coating layer 123 can be the same, and the material of the first coating layer 122 and the material of the second coating layer 123 can both be polyvinylidene fluoride.

[0165] In some embodiments, the first coating layer 122 and the second coating layer 123 can be coated simultaneously during the processing of the separator 12. For example, when the first coating layer 122 is coated without the second coating layer 123 being set in the region, the distance between the coating head and the first surface 1211 remains unchanged. When the first coating layer 122 is coated with the second coating layer 123 being set in the region, the distance between the coating head and the first surface 1211 is increased, so that the first coating layer 122 and the second coating layer 123 can be coated simultaneously.

[0166] It should be noted that after the coating of the first coating layer 122 and the second coating layer 123 is completed, the porosity of the second coating layer 123 can be improved by adding small holes to the second coating layer 123, so that the liquid absorption rate of the second coating layer 123 is greater than the liquid absorption rate of the first coating layer 122.

[0167] The technical solution of the embodiments of the present application sets the material of the first coating layer 122 and the material of the second coating layer 123 as the same material, so that the first coating layer 122 and the second coating layer 123 can be coated simultaneously, which is conducive to improving the convenience of processing and is conducive to improving the production efficiency of the battery device 100.

[0168] In some embodiments, the material of the second coating layer 123 is one of polyurethane, polyether ester elastic fiber, ultra-high molecular weight polyethylene, epoxy resin, acrylic resin, silicone resin, polystyrene maleic anhydride copolymer, and polyvinylidene fluoride.

[0169] In some embodiments, the polyether ester elastic fiber has high strength, good elasticity, and inexpensive raw materials, and is easy to produce and process.

[0170] In some embodiments, the ultra-high molecular weight polyethylene has good wear resistance, good self-lubricating performance, high impact strength, and excellent chemical corrosion resistance.

[0171] In some embodiments, the epoxy resin has excellent adhesion, can firmly adhere to various substrates such as metals, ceramics, wood, etc., and the coating formed thereby has high hardness, good wear resistance, and good chemical corrosion resistance, and can resist the corrosion of various acids, bases and other chemicals.

[0172] In some embodiments, the acrylic resin coating material has good weather resistance, can maintain the stability of the coating for a long time in outdoor environments, is not easy to fade and powder, and has good film-forming properties, flexibility, hardness and other properties.

[0173] In some embodiments, the silicone resin coating has good high-temperature resistance and low-temperature resistance, can maintain stable performance in a wide temperature range, and also has good electrical insulation.

[0174] In some embodiments, the polyvinylidene fluoride has good chemical stability, corrosion resistance, high-temperature resistance and mechanical properties, and good resistance to electrolyte, and is commonly used as a binder for lithium ion battery electrode materials and a coating layer for battery separators, which can improve the performance and safety of the battery.

[0175] In some embodiments, the polystyrene maleic anhydride copolymer has good chemical stability and thermal stability, and the polar groups in its molecular structure can improve the compatibility and resistance to electrolyte.

[0176] The technical scheme of the embodiment of the present application selects one of the above-mentioned materials as the material of the second coating layer 123, so that the liquid absorption rate of the second coating layer 123 is large, which helps to reduce the risk of ion precipitation between the second coating layer 123 and the first thinning area 1122.

[0177] In some embodiments, the material of the second coating layer 123 is polyurethane.

[0178] In some embodiments, the polyurethane material has good corrosion resistance, can be used in high-temperature environments, and can withstand the chemical components in the electrolyte without being easily corroded.

[0179] In some embodiments, the polyurethane material has good elasticity and can fit the inside of the electrode assembly 10, reducing the risk of damage to the separator 12.

[0180] In some embodiments, the polyurethane material has good high-temperature resistance and can remain stable at high temperatures inside the electrode assembly 10 without being easily deformed.

[0181] In some embodiments, the polyurethane material has good water absorption, and the ester bond and aldehyde group in the polyurethane material have hydrophilic groups, which can better absorb electrolyte.

[0182] The polyurethane has a typical two-phase structure, the polyether as the soft segment can be solvated with alkali metal salt to promote the transmission of ions, and the molecular hard segment formed by the polar group such as urethane can produce physical crosslinking points, so that it has good mechanical properties and film forming property.

[0183] The chemical formula of the polyurethane (PU) can be represented as (C10H8N2O2·C6H14O3)n, wherein n represents the polymerization degree, and because the polyurethane is a high molecular polymer, the value of n in the chemical formula is not fixed.

[0184] The technical scheme of the embodiment of the application selects polyurethane as the material of the second coating layer 123, so that the liquid absorption rate of the second coating layer 123 is large, which is beneficial to reduce the risk of ion precipitation between the second coating layer 123 and the first thinning area 1122.

[0185] Please refer to Figure 5 and Figure 6 In some embodiments, the number of the first thinning area 1122 is two, and the two first thinning areas 1122 are respectively located at the two ends of the first main body area 1121 in the width direction X of the first pole piece.

[0186] In some embodiments, the number of the first thinning area 1122 can be two, and the two first thinning areas 1122 are respectively connected to the two ends of the first main body area 1121 in the width direction X of the first pole piece.

[0187] Correspondingly, when the electrode assembly 10 is arranged in the shell 20, the width direction X of the first pole piece can be parallel to the direction of gravity, that is, the two ends of the electrode assembly 10 in the direction of gravity are provided with the first thinning area 1122, so that the first tab corresponding to the first pole piece 11 can be stretched out from any one end in the direction of gravity.

[0188] The technical scheme of the embodiment of the application is that the thickness of the first thinning area 1122 is less than the thickness of the first main body area 1121, that is, the first active material of the first thinning area 1122 is less, which reduces the risk of ion precipitation of the first thinning area 1122. By arranging the first thinning area 1122 at the two ends of the first main body area 1121 in the width direction X of the first pole piece, the risk of ion precipitation of the first pole piece 11 is further reduced, which is beneficial to improve the reliability of the battery device 100.

[0189] Please refer to Figure 4 and refer to Figure 7 and Figure 8 , Figure 7A matching diagram of the second tab and the separator provided for some embodiments of the present application, Figure 8 An exploded diagram of the second tab and the separator provided for some embodiments of the present application. The second thinned area and the second main area are separated by a dashed line. In some embodiments, the electrode assembly 10 further comprises a second tab 13, the first tab 11 and the second tab 13 are opposite in polarity, and the separator 12 is arranged between the first tab 11 and the second tab 13. The second tab 13 comprises a second current collector 131 and a second active material layer 132 arranged on at least one surface of the second current collector 131 in the thickness direction, the second active material layer 132 comprises a second main area 1321 and a second thinned area 1322 connected to the second main area 1321, the second thinned area 1322 is located at at least one end of the second main area 1321 in the width direction of the second tab 13, and the thickness of the second thinned area 1322 is less than the thickness of the second main area 1321. In the projection plane perpendicular to the thickness direction Y of the first tab, the orthographic projection of the first thinned area 1122 at least partially overlaps the orthographic projection of the second thinned area 1322.

[0190] In some embodiments, the second active material layer 132 can be arranged on the surface of the second current collector 131 facing the separator 12 in the thickness direction of the second tab 13.

[0191] In some embodiments, the second active material layer 132 can be arranged on the two opposite surfaces of the second current collector 131 in the thickness direction of the second tab 13.

[0192] In some embodiments, the first tab 11 can be opposite in polarity to the second tab 13, when the first tab 11 is a positive tab, the second tab 13 is a negative tab; when the first tab 11 is a negative tab, the second tab 13 is a positive tab.

[0193] In some embodiments, the electrode assembly 10 can be a wound structure, the first tab 11, the separator 12 and the second tab 13 are arranged along the thickness direction Y of the first tab, so that the thickness direction Y of the first tab, the thickness direction of the separator 12 and the thickness direction of the second tab 13 are parallel, and so that the width direction X of the first tab, the width direction of the separator 12 and the width direction of the second tab 13 are parallel, and so that the length direction of the first tab 11, the length direction of the separator 12 and the length direction of the second tab 13 are parallel.

[0194] Along the length direction of the first tab 11, the first tab 11, the separator 12 and the second tab 13 are wound to form a wound electrode assembly 10, and the separator 12 is always located between the first tab 11 and the second tab 13.

[0195] In some embodiments, the second tab 13 can be a positive electrode tab, and the second active material layer 132 can be a positive electrode active material layer.

[0196] In some embodiments, the second tab 13 can be a negative electrode tab, and the second active material layer 132 can be a negative electrode active material layer.

[0197] In some embodiments, the thickness direction Y of the first tab can be parallel to the thickness direction of the second tab 13.

[0198] In some embodiments, both surfaces of the second current collector 131 can be provided with the second active material layer 132 in the thickness direction Y of the first tab.

[0199] The second active material layer 132 can include a second main area 1321 and a second thinned area 1322, and the thickness of the second main area 1321 can be greater than the thickness of the second thinned area 1322 in the thickness direction Y of the first tab.

[0200] In some embodiments, the thickness of the second main area 1321 on both surfaces of the second current collector 131 can be the same or different.

[0201] In some embodiments, the thickness of the second thinned area 1322 on both surfaces of the second current collector 131 can be the same or different.

[0202] In some embodiments, similar to the processing of the first tab 11, during the processing of the second tab 13, the second active material can be uniformly coated on the surface of the second current collector 131 to form the second active material layer 132. After the coating is completed, the second active material in the partial area is thinned, thereby dividing the second active material layer 132 into the second main area 1321 and the second thinned area 1322. The partial area is the second thinned area 1322.

[0203] In some embodiments, the width direction X of the first tab can be parallel to the width direction of the second tab 13.

[0204] In some embodiments, the first tab 11 and the second tab 13 are projected on a projection plane perpendicular to the thickness direction Y of the first tab in the thickness direction Y of the first tab as the projection direction, to obtain the orthographic projection of the first tab 11 and the orthographic projection of the second tab 13.

[0205] In some embodiments, the orthographic projection of the first thinned area 1122 can cover the orthographic projection of the second thinned area 1322, or the orthographic projection of the second thinned area 1322 can cover the orthographic projection of the first thinned area 1122.

[0206] In some embodiments, in the width direction X of the first tab, the number of the second thinning regions 1322 can be one, and the second thinning region 1322 can be connected to one end of the second main body region 1321; the number of the second thinning regions 1322 can be two, and the two second thinning regions 1322 can be respectively connected to two ends of the second main body region 1321.

[0207] When the number of the first thinning regions 1122 is one, the number of the second thinning regions 1322 can be one, and the positions of the first thinning region 1122 and the second thinning region 1322 correspond; when the number of the first thinning regions 1122 is two, the number of the second thinning regions 1322 can also be two, and the two first thinning regions 1122 and the two second thinning regions 1322 are respectively correspondingly arranged.

[0208] The technical scheme of the embodiments of the present application sets the first tab 11 and the second tab 13 with opposite polarities to realize the charging and discharging of the battery monomer 1, and sets the isolating piece 12 between the first tab 11 and the second tab 13 to reduce the risk of short circuit caused by the contact between the first tab 11 and the second tab 13.

[0209] Please refer to Figure 7 and Figure 8 In some embodiments, the isolating piece 12 further comprises a third coating layer 124 and a fourth coating layer 125, the body 121 has a second surface 1212 facing the second tab 13, the third coating layer 124 is coated on the second surface 1212, the fourth coating layer 125 is coated on the side of the third coating layer 124 away from the second surface 1212, and in the thickness direction of the second tab 13, at least a part of the fourth coating layer 125 is located between the third coating layer 124 and the second thinning region 1322.

[0210] In some embodiments, in the thickness direction Y of the first tab, the body 121 can have a first surface 1211 and a second surface 1212, the first surface 1211 is the surface of the body 121 facing the first tab 11, and the second surface 1212 is the surface of the body 121 facing the second tab 13, wherein the first surface 1211 and the second surface 1212 are oppositely arranged.

[0211] In some embodiments, in the thickness direction Y of the first tab, a part of the third coating layer 124 can be located between the body 121 and the second main body region 1321, and another part of the third coating layer 124 can be located between the body 121 and the second thinning region 1322.

[0212] The fourth coating layer 125 is coated on the surface of the third coating layer 124 away from the second surface 1212, and is located between the third coating layer 124 and the second thinning area 1322. That is, the fourth coating layer 125 is located at at least one end of the third coating layer 124 in the width direction X of the first pole piece, and the orthographic projection of the second pole piece 13 and the spacer 12 on the projection surface perpendicular to the thickness direction Y of the first pole piece is obtained in the thickness direction Y of the first pole piece as the projection direction, wherein the orthographic projection of the fourth coating layer 125 covers the orthographic projection of the second thinning area 1322.

[0213] In some embodiments, the material of the third coating layer 124 can be a ceramic coating material such as silicon oxide, and can also be a polymer coating material such as polyvinylidene fluoride.

[0214] In some embodiments, the material of the third coating layer 124 can be polyvinylidene fluoride to improve the structural strength of the spacer 12 and improve the performance of the spacer 12 to absorb electrolyte, so as to facilitate the passage of electric ions through the spacer 12.

[0215] In some embodiments, the material of the fourth coating layer 125 can be polyurethane, polyether ester elastic fiber, ultra-high molecular weight polyethylene, epoxy resin, acrylic resin, silicone resin, polystyrene maleic anhydride copolymer, polyvinylidene fluoride, etc.

[0216] In some embodiments, the material of the fourth coating layer 125 can be polyurethane to improve the structural strength of the spacer 12 and improve the performance of the spacer 12 to absorb electrolyte, so as to facilitate the passage of electric ions through the spacer 12.

[0217] In some embodiments, the material of the first coating layer 122 can be the same as the material of the third coating layer 124.

[0218] In some embodiments, the material of the second coating layer 123 can be the same as the material of the fourth coating layer 125.

[0219] The thickness of the second thinning area 1322 gradually decreases in the direction close to the edge of the second pole piece 13, and the thickness of the fourth coating layer 125 gradually increases in the direction close to the edge of the spacer 12.

[0220] In some embodiments, the direction close to the edge of the second pole piece 13 can be parallel to the width direction X of the first pole piece.

[0221] In some embodiments, the thickness of the second thinning area 1322 can be the size of the second thinning area 1322 in the thickness direction Y of the first pole piece.

[0222] In some embodiments, the thickness of the fourth coating layer 125 can be greater than the thickness of the third coating layer 124 in the thickness direction Y of the first tab.

[0223] In some embodiments, the thickness of the second thinned area 1322 gradually decreases in a direction close to the edge of the second tab 13, i.e., a direction from the second main area 1321 to the second thinned area 1322. Similarly, the thickness of the fourth coating layer 125 gradually increases in a direction close to the edge of the separator 12, so that the second thinned area 1322 is connected to the fourth coating layer 125.

[0224] The technical solution of the embodiments of the present application reduces the risk of bubbles between the third coating layer 124 and the second thinned area 1322 in the thickness direction of the second tab 13 by arranging the fourth coating layer 125 between the third coating layer 124 and the second thinned area 1322, thereby reducing the risk of ion precipitation between the third coating layer 124 and the second thinned area 1322, and improving the reliability of the battery device 100.

[0225] In some embodiments, the liquid absorption rate of the fourth coating layer 125 is greater than the liquid absorption rate of the third coating layer 124.

[0226] Similarly to the first tab 11, taking the electrode assembly 10 as an example in a wound structure, the width direction X of the first tab can be parallel to the direction of gravity, and the second thinned area 1322 can be located above the second main area 1321. Due to the action of gravity, the electrolyte in the battery cell 1 infiltrates downward, resulting in less electrolyte existing in the area corresponding to the second thinned area 1322, i.e., less medium for carrying ions, thereby increasing the risk of ion precipitation. In some embodiments, the liquid absorption rate of the fourth coating layer 125 can be greater than the liquid absorption rate of the third coating layer 124, so that the fourth coating layer 125 can absorb more electrolyte, thereby increasing the amount of electrolyte existing in the area corresponding to the second thinned area 1322, and reducing the risk of ion precipitation.

[0227] In some embodiments, the liquid absorption rate of the fourth coating layer 125 can be the same as the liquid absorption rate of the second coating layer 123.

[0228] In some embodiments, the liquid absorption rate of the third coating layer 124 can be the same as the liquid absorption rate of the first coating layer 122.

[0229] The technical solution of the embodiments of the present application makes the liquid absorption rate of the fourth coating layer 125 greater than the liquid absorption rate of the third coating layer 124, so that the fourth coating layer 125 absorbs more electrolyte, thereby reducing the risk of ion precipitation between the fourth coating layer 125 and the second thinned area 1322.

[0230] Please refer to Figure 7 andFigure 8 In some embodiments, the fourth coating layer 125 is connected with the second thinned region 1322, and the third coating layer 124 is connected with the second body region 1321.

[0231] In some embodiments, in the thickness direction Y of the first tab, the surface of the third coating layer 124 away from the body 121 is provided with the fourth coating layer 125 on a part thereof, and is connected with the second body region 1321 on another part thereof.

[0232] In some embodiments, at least a part of the fourth coating layer 125 can be connected with the second thinned region 1322 in a manner of being attached to each other.

[0233] In some embodiments, the second tab 13 and the separator 12 are projected on a projection plane perpendicular to the thickness direction Y of the first tab with the thickness direction Y of the first tab as a projection direction, to obtain an orthographic projection of the second tab 13 and an orthographic projection of the separator 12, and the orthographic projection of the fourth coating layer 125 can overlap the orthographic projection of the second thinned region 1322, and the fourth coating layer 125 can be connected with the second thinned region 1322 in a manner of being attached to each other.

[0234] Alternatively, a part of the fourth coating layer 125 is connected with a part of the second thinned region 1322 in a manner of being attached to each other, and another part of the fourth coating layer 125 is provided apart from another part of the second thinned region 1322.

[0235] The technical scheme of the embodiments of the present application further reduces the gap between the third coating layer 124 and the second thinned region 1322 by connecting the fourth coating layer 125 with the second thinned region 1322, which is conducive to reducing the risk of ion precipitation and improving the reliability of the battery device 100.

[0236] Please refer to Figure 7 and Figure 8 In some embodiments, the first tab 11 is a negative electrode tab, and the second tab 13 is a positive electrode tab, and on the projection plane perpendicular to the thickness direction Y of the first tab, the orthographic projection of the first active material layer 112 covers the orthographic projection of the second active material layer 132, and the orthographic projection of the second coating layer 123 covers the orthographic projection of the fourth coating layer 125.

[0237] In the discharging process of the battery monomer 1, the ions of the positive electrode tab move to the negative electrode tab through the separator 12, that is, the ions of the second active material layer 132 move to the first active material layer 112, and in order to reduce the risk of ion precipitation caused by the fact that the first active material layer 112 cannot receive the ions, in some embodiments, the first active material layer 112 is more than the second active material layer 132.

[0238] Therefore, with the thickness direction Y of the first electrode as the projection direction, the first electrode 11 and the second electrode 13 are projected onto a projection plane perpendicular to the thickness direction Y of the first electrode, thus obtaining the orthographic projection of the first electrode 11 and the orthographic projection of the second electrode 13. The orthographic projection of the first active material layer 112 covers the orthographic projection of the second active material layer 132.

[0239] In some embodiments, in the width direction X of the first electrode, the first thinning region 1122 is located at at least one end of the first main body region 1121, and the second thinning region 1322 is located at at least one end of the second main body region 1321. That is, the first thinning region 1122 is the edge of the first active material layer 112, and the second thinning region 1322 is the edge of the second active material layer 132.

[0240] Since the second coating layer 123 corresponds to the first thinning area 1122 and the fourth coating area corresponds to the second thinning area 1322, in some embodiments, the isolation member 12 is projected onto a projection plane perpendicular to the thickness direction Y of the first electrode sheet, with the thickness direction Y of the first electrode sheet as the projection direction, to obtain the orthographic projection of the isolation member 12. The orthographic projection of the second coating layer 123 covers the orthographic projection of the fourth coating layer 125.

[0241] In the technical solution of this application embodiment, the first electrode 11 is a negative electrode, and the second electrode 13 is a positive electrode. During discharge, ions from the positive electrode move to the negative electrode. On the projection plane perpendicular to the thickness direction Y of the first electrode, by covering the projection of the first active material layer 112 with the projection of the second active material layer 132, the risk of ion deposition on the negative electrode is reduced. Simultaneously, correspondingly, the projection of the second coating layer 123 covers the projection of the fourth coating layer 125, further reducing the risk of ion deposition.

[0242] Please refer to Figure 4 In some embodiments, the electrode assembly 10 has a wound structure.

[0243] In the technical solution of this application embodiment, in the wound electrode assembly 10, a second coating layer 123 with a high liquid absorption rate is provided between the first coating layer 122 and the first thinning area 1122 in the thickness direction Y of the first electrode sheet, which helps to reduce the risk of lithium plating in the electrode assembly 10 and improve the reliability of the battery device 100.

[0244] Please refer to Figure 2 This application provides a battery device 100, which includes a battery cell 1 from any of the above embodiments.

[0245] Please refer to Figure 1The embodiments of the present application also provide a power utilization device, comprising the battery monomer 1 of any one of the above embodiments or the battery device 100 of any one of the above embodiments, and the battery monomer 1 or the battery device 100 is used to provide electric energy for the power utilization device.

[0246] Please refer to Figures 5 to 8 In some embodiments, the battery monomer 1 comprises the shell 20 and the electrode assembly 10, and the electrode assembly 10 is arranged in the shell 20.

[0247] In some embodiments, the electrode assembly 10 comprises the positive electrode tab, the negative electrode tab and the separator 12, and the separator 12 is arranged between the positive electrode tab and the negative electrode tab.

[0248] In some embodiments, the negative electrode tab comprises the first current collector 111 and the first active material layer 112, the positive electrode tab comprises the second current collector 131 and the second active material layer 132, and the separator 12 comprises the body 121, the first coating layer 122, the second coating layer 123, the third coating layer 124 and the fourth coating layer 125.

[0249] In the thickness direction Y of the first tab, the first active material layer 112 is arranged on the two surfaces of the first current collector 111 opposite to each other, the first active material layer 112 comprises the first main body area 1121 and two first thinned areas 1122, the thickness of the first main body area 1121 is greater than the thickness of the first thinned areas 1122, and the two first thinned areas 1122 are respectively arranged at the two ends of the first main body area 1121 in the width direction X of the first tab; the second active material layer 132 is arranged on the two surfaces of the second current collector 131 opposite to each other, the second active material layer 132 comprises the second main body area 1321 and two second thinned areas 1322, the thickness of the second main body area 1321 is greater than the thickness of the second thinned areas 1322, and the two second thinned areas 1322 are respectively arranged at the two ends of the second main body area 1321 in the width direction X of the first tab.

[0250] In some embodiments, in the thickness direction Y of the first tab, the material of the first coating layer 122 and the material of the third coating layer 124 can be the same, the first coating layer 122 is arranged on the first surface 1211 of the body 121 facing the negative electrode tab, and the third coating layer 124 is arranged on the second surface 1212 of the body 121 facing the positive electrode tab. The material of the first coating layer 122 and the material of the second coating layer 123 can both be polyvinylidene fluoride.

[0251] In some embodiments, the material of the second coating layer 123 and the material of the fourth coating layer 125 can be the same, the second coating layer 123 is arranged between the first coating layer 122 and the first thinning area 1122, and the second coating layer 123 can be connected with the first thinning area 1122 in a close manner; the fourth coating layer 125 is arranged between the second coating layer 123 and the second thinning area 1322, and the fourth coating layer 125 can be connected with the second thinning area 1322 in a close manner. The material of the third coating layer 124 and the material of the fourth coating layer 125 can both be polyurethane.

[0252] In the thickness direction Y of the first tab, by arranging the second coating layer 123 between the first coating layer 122 and the first thinning area 1122, the gap between the first coating layer 122 and the first thinning area 1122 is reduced, thereby reducing the risk of bubbles generated in the gap between the first coating layer 122 and the first thinning area 1122; by arranging the fourth coating layer 125 between the third coating layer 124 and the second thinning area 1322, the gap between the third coating layer 124 and the second thinning area 1322 is reduced, thereby reducing the risk of bubbles generated in the gap between the third coating layer 124 and the second thinning area 1322, reducing the risk of ion precipitation, and improving the reliability of the battery device 100.

[0253] In some embodiments, the liquid absorption rate of the second coating layer 123 can be greater than the liquid absorption rate of the first coating layer 122, and the liquid absorption rate of the fourth coating layer 125 can be greater than the liquid absorption rate of the third coating layer 124.

[0254] By making the liquid absorption rate of the second coating layer 123 greater than the liquid absorption rate of the first coating layer 122, the second coating layer 123 absorbs more electrolyte, which helps to reduce the risk of ion precipitation between the second coating layer 123 and the first thinning area 1122; and by making the liquid absorption rate of the fourth coating layer 125 greater than the liquid absorption rate of the third coating layer 124, the fourth coating layer 125 absorbs more electrolyte, which helps to reduce the risk of ion precipitation between the third coating layer 124 and the second thinning area 1322.

[0255] Although the present application has been described with reference to the preferred embodiments, various modifications can be made to it without departing from the scope of the application, and equivalent components can be substituted therefor. In particular, the technical features mentioned in each embodiment can be combined in any manner as long as there is no structural conflict. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized by, The electrode assembly includes: a first tab including a first current collector and a first active material layer provided on at least one surface of the first current collector in a thickness direction of the first tab, the first active material layer including a first main region and a first thinned region connected to the first main region, the first thinned region being located at at least one end of the first main region in a width direction of the first tab, the first thinned region having a thickness smaller than that of the first main region; a separator including a body having a first surface facing the first tab, a first coating layer coated on the first surface, and a second coating layer coated on a side of the first coating layer facing away from the first surface, at least a portion of the second coating layer being located between the first coating layer and the first thinned region in the thickness direction of the first tab; wherein a liquid absorption rate of the second coating layer is greater than a liquid absorption rate of the first coating layer.

2. The battery cell of claim 1, wherein, The second coating layer is connected to the first thinned region, and the first coating layer is connected to the first main region.

3. The battery cell of claim 2, wherein, In the thickness direction of the first tab, a surface of the second coating layer facing away from the first coating layer is connected to a surface of the first thinned region facing away from the first current collector.

4. The battery cell of claim 3, wherein, In a direction close to an edge of the first tab, the thickness of the first thinned region gradually decreases; in a direction close to an edge of the separator, the thickness of the second coating layer gradually increases.

5. The battery cell of claim 1, wherein, The liquid absorption rate of the second coating layer is 80% to 300%.

6. The battery cell of claim 5, wherein, The liquid absorption rate of the second coating layer is 220% to 300%.

7. The battery cell of claim 1, wherein, The material of the first coating layer and the material of the second coating layer are different.

8. The battery cell of claim 1, wherein, The material of the first coating layer and the material of the second coating layer are the same.

9. The battery cell according to claim 7 or 8, characterized in that, The material of the second coating layer is one of polyurethane, polyether ester elastic fiber, ultra-high molecular weight polyethylene, epoxy resin, acrylic resin, silicone resin, polystyrene maleic anhydride copolymer, and polyvinylidene fluoride.

10. The battery cell of claim 9, wherein, The material of the second coating layer is polyurethane.

11. The battery cell of claim 1, wherein, The number of the first thinned regions is two, and the two first thinned regions are respectively located at two ends of the first main region in the width direction of the first tab.

12. The battery cell of claim 1, wherein, The electrode assembly further includes a second tab, the first tab and the second tab being opposite in polarity, and the separator is disposed between the first tab and the second tab; The second tab includes a second current collector and a second active material layer provided on at least one surface of the second current collector in a thickness direction, the second active material layer including a second main region and a second thinned region connected to the second main region, the second thinned region being located at at least one end of the second main region in a width direction of the second tab, the second thinned region having a thickness smaller than that of the second main region; In a projection plane perpendicular to the thickness direction of the first tab, a normal projection of the first thinned region and a normal projection of the second thinned region at least partially overlap.

13. The battery cell of claim 12, wherein, The separator further includes a third coating layer and a fourth coating layer, the body has a second surface facing the second tab, the third coating layer is coated on the second surface, the fourth coating layer is coated on a side of the third coating layer away from the second surface, and in a thickness direction of the second tab, at least a portion of the fourth coating layer is located between the third coating layer and the second thinned region.

14. The battery cell of claim 13, wherein, The liquid absorption rate of the fourth coating layer is greater than the liquid absorption rate of the third coating layer.

15. The battery cell of claim 13, wherein, The fourth coating layer is connected with the second thinned region, and the third coating layer is connected with the second main body region.

16. The battery cell of claim 13, wherein, The first tab is a negative electrode tab, the second tab is a positive electrode tab, in a projection plane perpendicular to a thickness direction of the first tab, a positive projection of the first active material layer covers a positive projection of the second active material layer, and a positive projection of the second coating layer covers a positive projection of the fourth coating layer.

17. The battery cell of claim 1, wherein, The electrode assembly is in a wound structure.

18. A battery device characterized by comprising: A battery cell as claimed in any one of claims 1 to 17.

19. An electrical device, comprising: A battery cell as claimed in any one of claims 1 to 17 or a battery device as claimed in claim 18, for providing electrical energy to the electrical device.

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