Battery monomer, battery and electric equipment

Abstract

The embodiment of the utility model provides a battery monomer, a battery and electric equipment. The battery monomer comprises an electrode assembly and adhesive paper, the electrode assembly comprises a first pole piece, the adhesive paper is attached to the first pole piece, the adhesive paper comprises a base material, an adhesive layer and contrast agent particles, the adhesive layer is located on one side of the base material in the thickness direction, and the contrast agent particles are embedded in the adhesive layer. According to the technical scheme provided by the invention, the yield of the battery monomers can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of batteries, and more particularly, to a battery cell, a battery and an electrical device. Background Art

[0002] Energy conservation and emission reduction are the keys to the sustainable development of the automotive industry. Electric vehicles have become an important part of the sustainable development of the automotive industry due to their advantages of energy conservation and environmental protection. For electric vehicles, battery technology is an important factor related to their development.

[0003] In the development of battery technology, how to improve the yield rate of batteries is a technical problem that urgently needs to be solved in battery technology. Summary of the Utility Model

[0004] The present application provides a battery cell, a battery and an electrical device, which can improve the yield rate of the battery cell.

[0005] The present application is implemented through the following technical solutions:

[0006] In a first aspect, an embodiment of the present application provides a battery cell. The battery cell includes an electrode assembly and a sticker. The electrode assembly includes a first pole piece, and the sticker is attached to the first pole piece. The sticker includes a base material, an adhesive layer and contrast agent particles. The adhesive layer is located on one side in the thickness direction of the base material, and the contrast agent particles are embedded in the adhesive layer.

[0007] In the technical solution of the embodiment of the present application, the sticker includes a base material and an adhesive layer. The sticker can be adhered to the first pole piece of the electrode assembly through the adhesive layer on the base material. When the electrode assembly of the battery cell is wound and formed, it is impossible to visually inspect whether the sticker in the electrode assembly is folded. By embedding contrast agent particles in the adhesive layer, after the electrode assembly is wound and formed, the electrode assembly is irradiated by a contrast device (for example, an X-ray detector). The contrast agent particles in the adhesive layer can be projected and imaged with the contrast device, and it is possible to detect whether the sticker in the electrode assembly is folded according to the brightness difference of the image, so as to normally detect the electrode assembly with the sticker folded, reduce the risk of defective products flowing out, and thus improve the yield rate of the battery cell.

[0008] According to some embodiments of the present application, the base material is a porous material.

[0009] In the above solution, when the base material is a porous material, during the charge and discharge process of the battery cell, it is more conducive to active ions passing through the pores of the sticker, ensuring that the capacity of the area with the sticker attached in the battery cell can be normally exerted.

[0010] According to some embodiments of the present application, the base material has a first surface in the thickness direction, the adhesive layer is disposed on the first surface, and the first surface includes a glue-coated area coated with the adhesive layer and a blank area not coated with the adhesive layer.

[0011] In the above solution, the first surface of the substrate includes an adhesive application area and a blank area. When the adhesive tape is applied to the electrode of the battery cell, during the charge and discharge process of the battery cell, since the adhesive layer will block the active ions of the battery cell, the setting of the blank area on the first surface is more conducive to the active ions passing through the pores of the adhesive tape, effectively reducing the risk of lithium plating.

[0012] According to some embodiments of the present application, the porosity of the substrate is not less than 35% and not greater than 65%.

[0013] In the above solution, controlling the porosity of the substrate within this range can not only ensure the normal passage of active ions through the adhesive tape but also does not affect the stability of the strength of the substrate itself. When the porosity of the substrate is less than 35%, the porosity is too small and the number of pores is small, which easily affects the passing efficiency of active ions through the adhesive tape. When the porosity of the substrate is greater than 65%, the excessive porosity affects the strength of the substrate.

[0014] According to some embodiments of the present application, the electrode assembly is of a wound structure. The electrode assembly further includes a second electrode and a separator. The first electrode and the second electrode have opposite polarities, and the separator is disposed between the first electrode and the second electrode; wherein, at least one bent section of the first electrode is provided with an adhesive tape.

[0015] In the above solution, the adhesive layer of the adhesive tape can be attached to at least one bent section of the first electrode. On the one hand, the adhesive tape can protect the bent section of the first electrode, reducing the risk of cracking and powder shedding in the area of the first electrode where the adhesive tape is attached, thereby reducing the risk of the separator being punctured during the cycle of the battery cell and causing short circuit between the positive and negative electrodes. On the other hand, when the substrate of the adhesive tape is a porous material and the first surface of the substrate has a blank area without an adhesive layer, during the charge and discharge process of the battery cell, active ions (such as lithium ions) can normally pass through the blank area of the adhesive tape where there is no adhesive layer. Compared with the case where the adhesive layer is fully covered on the first surface of the substrate, the area for active ions to pass through the adhesive tape is increased, and the blocking effect of the adhesive tape on the movement of active ions is reduced, so that the capacity of the area of the battery cell with the adhesive tape can be normally exerted. And since the active ions can normally pass through the adhesive tape, the active ions are not easily accumulated at the edge of the adhesive tape, thereby reducing the risk of lithium plating of the battery cell.

[0016] According to some embodiments of the present application, adhesive tapes are attached to both sides in the thickness direction of at least one bent section.

[0017] In the above solution, adhesive tapes are attached to both sides in the thickness direction of at least one bent section. With the protection of the adhesive tapes on both sides in the thickness direction of the bent section of the first pole piece, the compressive capacity on both sides of the bent section of the pole piece is relatively more balanced, and the pole piece is not prone to cracking, ensuring the safety of the battery cell. It can also reduce the risk of metal ions precipitating on the surface of the negative pole piece.

[0018] According to some embodiments of the present application, an adhesive tape is attached to the innermost bent section of the first pole piece.

[0019] In the above solution, when shaping the battery cell, since the folding amount of the innermost bent section of the first pole piece is the largest, the first pole piece is more prone to cracking and powder shedding. Therefore, by attaching an adhesive tape to the innermost bent section of the first pole piece, it can protect the innermost bent section of the first pole piece, thereby reducing the risk of cracking and powder shedding of the first pole piece.

[0020] According to some embodiments of the present application, the first pole piece is a positive pole piece.

[0021] According to some embodiments of the present application, the first pole piece includes a first pole tab. In the width direction of the first pole piece, the separator has a first edge corresponding to the first pole tab, and the first pole tab extends beyond the first edge; in the width direction of the first pole piece, the adhesive tape includes a first end corresponding to the first edge, and the first end does not extend beyond the first edge.

[0022] In the above solution, by setting the first end of the adhesive tape not to extend beyond the first edge, it can prevent the sensor from misidentifying the first end of the base material as the first pole tab during the manufacturing process, thereby avoiding the phenomenon of false reporting of the pole tab and affecting the manufacturing efficiency of the battery.

[0023] According to some embodiments of the present application, the separator further includes a second edge opposite to the first edge, and the adhesive tape includes a second end corresponding to the second edge, and the second end extends beyond the second edge.

[0024] In the above solution, by making the second end of the adhesive tape extend beyond the second edge, it is convenient to detect whether the adhesive tape is missed or folded during the manufacturing process of the electrode assembly, which is more conducive to controlling the yield rate of the battery cell.

[0025] In a second aspect, the present application provides a battery, which includes the battery cell in the above embodiments.

[0026] In a third aspect, the present application provides an electrical device, which includes the battery cell or the battery in the above embodiments, and the battery cell or the battery is used to provide electrical energy.

[0027] Additional aspects and advantages of the present application will be given in part in the following description, become apparent in part from the following description, or be learned by practice of the present application. Description of the Drawings

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application and should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other relevant drawings can also be obtained based on these drawings.

[0029] Figure 1 Structural schematic diagram of a vehicle according to some embodiments of the present application;

[0030] Figure 2 Exploded structural schematic diagram of a battery according to some embodiments of the present application;

[0031] Figure 3 Cross-sectional structural schematic diagram of an electrode assembly in a battery cell according to some embodiments of the present application;

[0032] Figure 4 Cross-sectional view of adhesive tape disposed on a first pole piece according to some embodiments of the present application;

[0033] Figure 5 Structural schematic diagram of the adhesive tape of the first pole piece after being folded according to some embodiments of the present application;

[0034] Figure 6 Schematic diagram of a battery cell in a detection state on a bottom support plate according to some embodiments of the present application;

[0035] Figure 7 Structural schematic diagram of the first pole piece in a battery cell before winding according to some embodiments of the present application;

[0036] Figure 8 Structural schematic diagram of the adhesive tape in the first pole piece of a battery cell according to some embodiments of the present application.

[0037] Icons: 10 - box body; 11 - first part; 12 - second part; 20 - battery cell; 22 - electrode assembly; 221 - first pole piece; 2210 - first tab; 2211 - first bending section; 2212 - second bending section; 222 - second pole piece; 23 - adhesive tape; 230 - base material; 231 - adhesive layer; 232 - first end; 233 - second end; 2341 - glue - applying area; 2342 - blank area; 235 - contrast agent particles; 24 - separator; 241 - first edge; 242 - second edge; 243 - folding part; 100 - battery; 200 - controller; 300 - motor; 400 - bottom plate; 500 - detector; 1000 - vehicle. Detailed implementation manners

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Apparently, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0039] Unless otherwise defined, all technical and scientific terms used in the present application have the same meanings as those commonly understood by those skilled in the technical field to which the present application belongs; the terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application; the terms "including" and "having" and any variations thereof in the specification and claims of the present application and the above - mentioned drawings are intended to cover non - exclusive inclusion. The terms "first", "second", etc. in the specification and claims of the present application or the above - mentioned drawings are used to distinguish different objects and are not used to describe a specific order or primary - secondary relationship.

[0040] Referring to "embodiments" in the present application means that specific features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of the present application. The phrase appears in various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described in the present application can be combined with other embodiments.

[0041] In the description of the present application, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", "linked", and "attached" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0042] In the present application, the term "and / or" is merely a description of the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the present application, the character " / " generally represents an "or" relationship between the front and back associated objects.

[0043] In the present application, "a plurality of" refers to two or more (including two). Similarly, "multiple groups" refers to two or more groups (including two groups), and "multiple sheets" refers to two or more sheets (including two sheets).

[0044] In some embodiments, the battery can be a battery module. When there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0045] In some embodiments, the battery can be a battery pack. The battery pack includes a box body and battery cells, and the battery cells or battery modules are accommodated in the box body.

[0046] In some embodiments, the box body can be part of the chassis structure of a vehicle. For example, part of the box body can become at least part of the floor of the vehicle, or part of the box body can become at least part of the cross beam and longitudinal beam of the vehicle.

[0047] In some embodiments, the battery can be an energy storage device. The energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0048] In the embodiments of the present application, the battery cell can be a secondary battery, and a secondary battery refers to a battery cell that can be activated by charging after discharging to continue to be used.

[0049] 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-metal hydride battery, a nickel-cadmium battery, a lead-acid battery, etc.

[0050] 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. The prismatic battery cell includes a square shell battery cell.

[0051] A battery cell generally includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of the battery cell, active ions (such as lithium ions) are inserted into and extracted from between the positive electrode and the negative electrode. The separator is disposed between the positive electrode and the negative electrode, which can prevent the short circuit between the positive and negative electrodes and allow the active ions to pass through.

[0052] In some embodiments, the positive electrode can be a positive electrode tab, and the positive electrode tab can include a positive current collector and a positive active material disposed on at least one surface of the positive current collector.

[0053] As an example, the positive current collector has two surfaces opposite to each other in its own thickness direction, and the positive active material is disposed on either or both of the two opposite surfaces of the positive current collector.

[0054] As an example, the positive current collector can be a metal foil or a composite current collector. For example, as the metal foil, aluminum with silver plating on the surface, stainless steel with silver plating on the surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc. can be used. The composite current collector can include a polymer material substrate and a metal layer. The composite current collector can be formed by forming a metal material (such as aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0055] As an example, the positive active material can include at least one of the following materials: lithium-containing phosphate, lithium transition metal oxide, and their respective modified compounds. However, the present application is not limited to these materials, and other conventional materials that can be used as battery positive active materials can also be used.

[0056] In some embodiments, the negative electrode can be a negative electrode tab, and the negative electrode tab can include a negative current collector.

[0057] As an example, the negative current collector can be a metal foil or a composite current collector. For example, as the metal foil, aluminum with silver plating on the surface, stainless steel with silver plating on the surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc. can be used.

[0058] In some embodiments, the negative current collector has two surfaces opposite to each other in its own thickness direction, and the negative active material is disposed on either or both of the two opposite surfaces of the negative current collector.

[0059] As an example, the negative electrode active material can be the negative electrode active material for batteries known in the art. As an example, the negative electrode active material can include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. The silicon-based materials can be selected from at least one of elemental silicon, silicon oxides, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based materials can be selected from at least one of elemental tin, tin oxides, and tin alloys. However, the present application is not limited to these materials, and other conventional materials that can be used as the negative electrode active material of the battery can also be used. These negative electrode active materials can be used alone or in combination of two or more.

[0060] In some embodiments, the separator is a diaphragm. The present application does not particularly limit the type of the diaphragm, and any known porous structure diaphragm with good chemical stability and mechanical stability can be selected.

[0061] As an example, the main material of the diaphragm can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramics. The diaphragm can be a single-layer film or a multi-layer composite film, without particular limitation. When the diaphragm is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation. The separator can be a single component located between the positive and negative electrodes, or can be attached to the surfaces of the positive and negative electrodes.

[0062] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive electrode and the negative electrode, and simultaneously functions to transport ions and isolate the positive and negative electrodes.

[0063] In some embodiments, the electrode assembly has a wound structure. The positive electrode sheet and the negative electrode sheet are wound into a wound structure.

[0064] Currently, from the perspective of the development of the market situation, the application of power batteries is becoming more and more extensive. Power batteries are not only applied to energy storage power systems such as hydropower, thermal power, wind power, and solar power plants, but also widely applied to electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as multiple fields such as military equipment and aerospace. With the continuous expansion of the application fields of power batteries, the market demand for them is also continuously increasing.

[0065] The development of battery technology needs to consider multiple design factors simultaneously. For example, performance parameters such as energy density, charge-discharge rate, and discharge capacity of the battery. In addition, the yield rate of the battery also needs to be considered.

[0066] At present, during the shaping process of a wound bare electrode assembly, corner cracking and powder shedding are likely to occur. In order to alleviate the problem of electrode sheet cracking and powder shedding, in the prior art, it is usually adopted to stick adhesive tape on the electrode sheet of the electrode assembly, especially at the bent section of the electrode sheet, to solve the problems of cracking and powder shedding of the bent section of the electrode sheet of the electrode assembly due to pressure. However, after the adhesive tape is stuck on the electrode assembly, there is a risk of the adhesive tape folding during the winding process of the electrode assembly. Since the wound electrode assembly has a wound structure after winding, there is no detection method for the folded adhesive tape, which is likely to cause defective products of the battery cell to flow out, reducing the yield rate of the battery cell.

[0067] Based on the above considerations, in order to improve the reliability of the battery cell, the present application designs a battery cell. The battery cell includes an electrode assembly and an adhesive tape. The electrode assembly includes a first electrode sheet. The adhesive tape includes a base material, an adhesive layer, and contrast agent particles. The base material is stuck on the first electrode sheet through the adhesive layer, and the contrast agent particles are embedded in the adhesive layer.

[0068] In such a battery cell, by adding contrast agent particles to the adhesive layer, after the winding of the electrode assembly is completed, the electrode assembly is comprehensively detected by a detection device (for example, an X-ray detector). The X-ray detector can image the adhesive tape with contrast agent particles in the electrode assembly, and judge whether the adhesive tape is folded according to the brightness color difference after imaging, so as to ensure that the electrode assembly after the adhesive tape is folded can be normally detected, reducing the risk of defective products flowing out and improving the yield rate of the battery cell.

[0069] The battery cell disclosed in the embodiments of the present application can be but is not limited to being used in electrical equipment such as vehicles, ships, or aircraft. A power supply system of the electrical equipment can be composed of the battery cell, battery, etc. disclosed in the present application.

[0070] The embodiments of the present application provide an electrical equipment using a battery as a power source. The electrical equipment can be but is not limited to mobile phones, tablets, laptop computers, electric toys, electric tools, battery cars, electric vehicles, ships, spacecraft, etc. Among them, the electric toys can include fixed or mobile electric toys, such as game consoles, electric vehicle toys, electric ship toys, and electric aircraft toys, etc. The spacecraft can include airplanes, rockets, space shuttles, and spaceships, etc.

[0071] For the convenience of description in the following embodiments, a vehicle is taken as an example of an electrical equipment in an embodiment of the present application for illustration.

[0072] Please refer to Figure 1 , Figure 1Schematic structural diagram of vehicle 1000 provided by some embodiments of the present application. Vehicle 1000 can be a fuel vehicle, a gas vehicle, or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle, an extended-range vehicle, etc. A battery 100 is disposed inside vehicle 1000. The battery 100 can be disposed at the bottom, the head, or the tail of vehicle 1000. The battery 100 can be used for power supply of vehicle 1000. For example, the battery 100 can be used as the operating power source of vehicle 1000. Vehicle 1000 can also include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to supply power to the motor 300. For example, it is used for the working power requirements during the start, navigation, and driving of vehicle 1000.

[0073] In some embodiments of the present application, the battery 100 can not only be used as the operating power source of vehicle 1000, but also as the driving power source of vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for vehicle 1000.

[0074] Please refer to Figure 2 , Figure 2 Explosion diagram of battery 100 provided by some embodiments of the present application. The battery 100 includes a box body 10 and battery cells 20. The battery cells 20 are accommodated in the box body 10. Among them, the box body 10 is used to provide an accommodation space for the battery cells 20, and the box body 10 can adopt various structures. In some embodiments, the box body 10 can include a first part 11 and a second part 12. The first part 11 and the second part 12 are covered with each other, and the first part 11 and the second part 12 jointly define an accommodation space for accommodating the battery cells 20. The second part 12 can be a hollow structure with one end open, and the first part 11 can be a plate-like structure. The first part 11 is covered on the opening side of the second part 12 so that the first part 11 and the second part 12 jointly define an accommodation space; the first part 11 and the second part 12 can also both be hollow structures with one side open, and the opening side of the first part 11 is covered on the opening side of the second part 12. Of course, the box body 10 formed by the first part 11 and the second part 12 can be in various shapes, such as a cylinder, a cuboid, etc.

[0075] In the battery 100, there may be multiple battery cells 20. The multiple battery cells 20 can be connected in series, parallel, or in a combined series-parallel connection. A combined series-parallel connection means that there are both series and parallel connections among the multiple battery cells 20. The multiple battery cells 20 can be directly connected in series, parallel, or in a combined series-parallel connection together, and then the whole formed by the multiple battery cells 20 is accommodated in the box body 10. Of course, the battery 100 can also be such that multiple battery cells 20 are first connected in series, parallel, or in a combined series-parallel connection to form a battery module, and then multiple battery modules are connected in series, parallel, or in a combined series-parallel connection to form a whole and are accommodated in the box body 10. The battery 100 can also include other structures. For example, the battery 100 can also include a busbar component for realizing the electrical connection among the multiple battery cells 20.

[0076] Among them, each battery cell 20 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery.

[0077] A battery cell 20 refers to the smallest unit that makes up a battery. The battery cell 20 includes an end cap, a housing, an electrode assembly, and other functional components.

[0078] The end cap refers to a component that covers the opening of the housing to isolate the internal environment of the battery cell 20 from the external environment. Without limitation, the shape of the end cap can be adapted to the shape of the housing to cooperate with the housing. Optionally, the end cap can be made of a material with a certain hardness and strength (such as aluminum alloy). In this way, the end cap is not easily deformed when subjected to extrusion and collision, enabling the battery cell to have higher structural strength and improved reliability. Functional components such as electrode terminals can be provided on the end cap. The electrode terminals can be used for electrically connecting to the electrode assembly to output or input the electrical energy of the battery cell 20. The material of the end cap can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. The embodiments of the present application do not make special restrictions on this. In some embodiments, an insulating structure can also be provided on the inner side of the end cap. The insulating structure can be used to isolate the electrical connection components in the housing from the end cap to reduce the risk of short circuit. Exemplarily, the insulating structure can be plastic, rubber, etc.

[0079] The electrode assembly is the component in the battery cell 20 where an electrochemical reaction occurs. The housing can contain one or more electrode assemblies. The electrode assembly is mainly formed by winding or laminating a positive electrode plate and a negative electrode plate, and usually a separator is provided between the positive electrode plate and the negative electrode plate to separate the positive electrode plate and the negative electrode plate to avoid internal short circuit between the positive electrode plate and the negative electrode plate. The parts of the positive electrode plate and the negative electrode plate with active substances constitute the main body of the electrode assembly, and the parts of the positive electrode plate and the negative electrode plate without active substances respectively constitute the electrode tabs. The positive electrode tab and the negative electrode tab can be located at one end of the main body together or at both ends of the main body respectively.

[0080] An embodiment of the present application provides a battery cell. Please refer to Figure 3 and Figure 4 , Figure 3 which is a schematic cross-sectional structure diagram of an electrode assembly in a battery cell according to some embodiments of the present application. Figure 4 is a cross-sectional view of an adhesive tape attached to a first electrode tab according to some embodiments of the present application. The battery cell 20 includes an electrode assembly 22 and an adhesive tape 23. The electrode assembly 22 includes a first electrode tab 221. The adhesive tape 23 is attached to the first electrode tab 221. The adhesive tape 23 includes a base material 230, an adhesive layer 231, and contrast agent particles 235. The adhesive layer 231 is located on one side of the base material 230 in the thickness direction Z. The contrast agent particles 235 are embedded in the adhesive layer 231.

[0081] The adhesive tape 23 is attached to the first electrode tab 221 through the adhesive layer 231. The adhesive tape 23 can be attached to one side of the first electrode tab 221 in the thickness direction Z, or can be attached to both sides of the first electrode tab 221 in the thickness direction Z. The material of the adhesive layer 231 can be maleic anhydride modified polypropylene or acrylic acid, etc. The contrast agent particles 235 are embedded in the adhesive layer 231. It can be understood that when the adhesive tape 23 is prepared, the contrast agent particles 235 are embedded in the adhesive layer 231 and then coated on the surface of the base material 230, or after the adhesive layer 231 is coated on the surface of the base material 230, the contrast agent particles 235 are embedded in the adhesive layer 231. The contrast agent is in the form of particles. The contrast agent can include barium sulfate and iodine preparations, which are high-density contrast agents with good contrast. Of course, the type of iodine preparation can be meglumine diatrizoate or sodium diatrizoate, etc.

[0082] Please refer to Figure 5 , Figure 5 which is a schematic structural diagram of the adhesive tape of the first electrode tab after being folded according to some embodiments of the present application. One end of the base material 230 will form a folded portion 243 after being folded. The folded portion 243 will overlap on the base material 230. In this way, when the electrode assembly 22 is imaged, the brightness of the image at the folded portion 243 will be different from the brightness of the rest of the base material 230. In this way, it can be determined whether the adhesive tape 23 of the electrode assembly 22 is folded by judging whether there is a brightness difference on the base material 230.

[0083] In the technical solution of the embodiment of the present application, the adhesive tape 23 includes a base material 230 and an adhesive layer 231. The adhesive tape 23 can be adhered to the first electrode tab 221 of the electrode assembly 22 through the adhesive layer 231 on the base material 230. When the electrode assembly 22 is wound into a shape, it is impossible to visually detect whether the adhesive tape 23 inside the electrode assembly 22 is folded. By embedding contrast agent particles 235 in the adhesive layer 231, after the electrode assembly 22 is wound into a shape, please refer to Figure 6 , Figure 6Schematic diagram of a battery cell in a detection state on a bottom support plate according to some embodiments of the present application. The electrode assembly 22 is placed on the bottom support plate 400. By irradiating the electrode assembly 22 with a contrast imaging device (e.g., an X-ray detector 500), the contrast agent particles 235 in the adhesive layer 231 can be imaged by the contrast imaging device. Whether the adhesive tape 23 in the electrode assembly 22 is folded can be detected according to the brightness difference of the imaging, and the electrode assembly 22 with the folded adhesive tape 23 can be normally detected, reducing the risk of defective products flowing out, and thus improving the yield rate of the battery cell.

[0084] According to some embodiments of the present application, the substrate 230 is a porous material.

[0085] The porous material here refers to a material with many tiny pores that can filter larger particles but allow metal ions to pass through.

[0086] The material of the substrate 230 can be polypropylene, polyethylene, non-woven fabric, etc. Polypropylene, abbreviated as PP, is a polymer formed by the addition polymerization of propylene. Polypropylene is a thermoplastic synthetic resin with excellent properties and is a colorless, semi-transparent thermoplastic lightweight general-purpose plastic. Polyethylene (abbreviated as PE) is a thermoplastic resin obtained by the polymerization reaction of ethylene monomers. Non-woven fabric, also known as non-woven cloth, needle-punched cotton, needle-punched non-woven fabric, etc., is produced using polyester fiber and polyester fiber (abbreviated as PET) materials and is made by the needle-punching process.

[0087] Using the substrate 230 as a porous material is more conducive to the penetration of active ions through the pores of the adhesive tape 23 during the charge and discharge process of the battery cell, ensuring that the capacity of the area where the adhesive tape 23 is pasted in the battery cell can be normally exerted.

[0088] According to some embodiments of the present application, please refer to Figure 8 , Figure 8 Schematic diagram of the structure of the adhesive tape in the first electrode sheet of a battery cell according to some embodiments of the present application. The substrate 230 has a first surface in the thickness direction Z. The adhesive layer 231 is disposed on the first surface. The first surface includes a coated area 2341 coated with the adhesive layer 231 and a blank area 2342 not coated with the adhesive layer 231.

[0089] The first surface of the substrate 230 is the entire surface along the thickness direction Z of the substrate 230. The coated area 2341 refers to all areas of the substrate 230 coated with the adhesive layer 231, and the blank area 2342 is the area of the first surface of the substrate 230 not coated with the adhesive layer 231.

[0090] The blank area 2342 on the first surface of the base material 230 can have various forms. For example, the adhesive layer 231 can include a plurality of sub - adhesive layers 231, and the plurality of sub - adhesive layers 231 are distributed at intervals in a strip shape on the first surface of the base layer. The area between two adjacent sub - adhesive layers 231 forms the blank area 2342. Of course, the adhesive layer 231 can also be applied on the first surface of the base material 230 in a dot - like distribution, a checkerboard pattern, a grid pattern, or any other shape.

[0091] Please refer to Figure 8 , Figure 8 is a schematic structural diagram of the adhesive tape in the first electrode sheet of a battery cell according to some embodiments of the present application. The first surface of the base material 230 includes a coated area 2341 and a blank area 2342. During the charge and discharge process of the battery cell, since the adhesive layer 231 will block the active ions of the battery cell, the setting of the blank area 2342 on the first surface is more conducive to the active ions passing through the pores of the adhesive tape 23, effectively reducing the risk of lithium deposition.

[0092] According to some embodiments of the present application, the porosity of the base material 230 is not less than 35% and not more than 65%.

[0093] The porosity of the base material 230 can be any value from 35% to 65%. For example, the porosity of the base material 230 can be 35%, 40%, 45%, 50%, 55%, 60%, 65%, etc.

[0094] Controlling the porosity of the base material 230 within this range can not only ensure the normal passage of active ions through the adhesive tape 23 but also does not affect the stability of the strength of the base material 230 itself. When the porosity of the base material 230 is less than 35%, the porosity is too small and the number of pores is small, which easily affects the passing efficiency of active ions through the adhesive tape 23. When the porosity of the base material 230 is greater than 65%, the porosity is too large and affects the strength of the base material 230.

[0095] According to some embodiments of the present application, please refer to Figure 3 , the electrode assembly 22 is a wound structure. The electrode assembly 22 further includes a second electrode sheet 222 and a separator 24. The first electrode sheet 221 and the second electrode sheet 222 have opposite polarities, and the separator 24 is disposed between the first electrode sheet 221 and the second electrode sheet 222; wherein, an adhesive tape 23 is attached to at least one bent section of the first electrode sheet 221.

[0096] The electrode assembly 22 has a wound structure. The wound structure is formed by winding around a fixed winding needle. The first electrode sheet 221 and the second electrode sheet 222 are respectively one of the positive electrode sheet and the negative electrode sheet. The separator 24 is disposed between the first electrode sheet 221 and the second electrode sheet 222, which can prevent the first electrode sheet 221 and the second electrode sheet 222 from short - circuiting, and at the same time allows active ions to pass through. The main body of the electrode assembly 22 includes a straight section and a bent section. The bent section is connected to one end of the straight section. The first electrode sheet 221 of the straight section extends along a straight - line trajectory, and the electrode sheet of the bent section extends along a bent trajectory.

[0097] The adhesive tape 23 can be attached to at least one bent section of the first electrode sheet 221. On the one hand, the adhesive tape 23 can protect the bent section of the first electrode sheet 221, reducing the risk of cracking and powder shedding in the area of the first electrode sheet 221 where the adhesive tape 23 is attached, thereby reducing the risk of the separator 24 being punctured during the cycling of the battery cell, resulting in short - circuiting of the positive and negative electrodes.

[0098] On the other hand, when the base material 230 of the adhesive tape 23 is a porous material and the first surface of the base material 230 has a blank area where the adhesive layer 231 is not coated, during the charge - discharge process of the battery cell, active ions (such as lithium ions) can normally pass through the blank area of the adhesive tape 23 where the adhesive layer 231 is not provided. Compared with the case where the adhesive layer 231 is fully covered on the first surface of the base material 230, the area for active ions to pass through the adhesive tape 23 is increased, the blocking effect of the adhesive tape 23 on the movement of active ions is reduced, so that the capacity of the area of the battery cell where the adhesive tape 23 is attached can be normally exerted. And since the active ions can normally pass through the adhesive tape 23, the active ions are not likely to accumulate at the edge of the adhesive tape 23, thereby reducing the risk of metal ions precipitating on the surface of the negative electrode sheet.

[0099] Among them, the adhesive tape 23 can be attached to one side of the corresponding bent section of the first electrode sheet 221, or can be attached to both sides in the thickness direction of the corresponding bent section of the first electrode sheet 221. When the adhesive tape 23 is attached to one side of the first electrode sheet 221, it is preferably attached to the inner side of the first electrode sheet 221, which can further reduce the risk of lithium deposition. However, uneven pressure is likely to occur on the outer side of the first electrode sheet 221, making the outer side of the first electrode sheet 221 more likely to crack.

[0100] According to some embodiments of the present application, adhesive tapes 23 are attached to both sides in the thickness direction of at least one bent section of the first electrode sheet 221.

[0101] Adhesive tapes 23 are attached to both sides of at least one bent section of the first electrode tab 221 in the thickness direction. With the protection of the adhesive tapes 23 on both sides of the bent section of the first electrode tab 221 in the thickness direction, the compressive resistance on both sides of the bent section of the first electrode tab 221 is relatively more balanced, the electrode tab is not prone to cracking, ensuring the safety of the battery cell, and also reducing the risk of metal ions precipitating on the surface of the negative electrode tab.

[0102] According to some embodiments of the present application, an adhesive tape 23 is attached to the innermost bent section of the first electrode tab 221.

[0103] When the electrode assembly 22 is wound, please refer to Figure 3 , the force on the innermost bent section of the first electrode tab 221 in the electrode assembly 22 is the greatest, the folding amount is the largest, and the innermost bent section is the most prone to cracking and powder shedding.

[0104] In this embodiment, the adhesive tapes 23 are arranged on the first bent section 2211 and the second bent section 2212 of the innermost circle of the first electrode tab 221. That is to say, the first bent section 2211 and the second bent section 2212 are the two bent sections formed by the first winding of the first electrode tab 221 during winding.

[0105] When shaping the battery cell, since the folding amount of the innermost bent section of the first electrode tab 221 is the largest and it is more prone to cracking and powder shedding of the first electrode tab 221, an adhesive tape 23 is attached to the innermost bent section of the first electrode tab 221, thereby protecting the innermost bent section of the first electrode tab 221 and reducing the risk of cracking and powder shedding of the first electrode tab 221.

[0106] According to some embodiments of the present application, the first electrode tab 221 is a positive electrode tab.

[0107] According to some embodiments of the present application, please refer to Figure 7 , Figure 7 is a schematic structural diagram of the first electrode tab in the battery cell of some embodiments of the present application before winding. The first electrode tab 221 includes a first tab 2210. In the width direction X of the first electrode tab 221, the separator 24 has a first edge 241 corresponding to the first tab 2210, and the first tab 2210 extends beyond the first edge 241; in the width direction X of the first electrode tab 221, the adhesive tape 23 includes a first end 232 corresponding to the first edge 241, and the first end 232 does not extend beyond the first edge 241.

[0108] The first edge 241 refers to the edge of the separator 24 that is closer to the first tab 2210 along the width direction X of the first electrode tab 221. The first end 232 refers to the end of the adhesive tape 23 that is closer to the first tab 2210 along the width direction X of the first electrode tab 221. The width direction X, the length direction Y, and the thickness direction Z of the first electrode tab 221 are perpendicular to each other in pairs.

[0109] The first end 232 of the adhesive tape 23 is set not to exceed the first edge 241, so as to prevent the sensor from misidentifying the first end 232 of the base material 230 as the first tab 2210 during the manufacturing process, thereby avoiding the phenomenon of false tab reporting and affecting the manufacturing efficiency of the battery.

[0110] According to some embodiments of the present application, please refer to Figure 7 , the separator 24 further includes a second edge 242 disposed opposite to the first edge 241, and the adhesive tape 23 includes a second end 233 corresponding to the second edge 242, and the second end 233 extends beyond the second edge 242.

[0111] The second edge 242 refers to the other edge of the separator 24 that is opposite to the first edge 241 along the width direction X of the first electrode tab 221. The second end 233 refers to the other end of the adhesive tape 23 that is opposite to the first end along the width direction X of the first electrode tab 221.

[0112] By making the second end 233 of the adhesive tape 23 extend beyond the second edge 242, it is convenient to detect whether the adhesive tape 23 is missed during the manufacturing process of the electrode assembly 22, or whether the adhesive tape 23 is folded, which is more conducive to controlling the yield rate of the battery cell and improving the reliability of the battery cell.

[0113] In a second aspect, the present application provides a battery, which includes the battery cell 20 in the above embodiments.

[0114] In a third aspect, the present application provides an electrical device, which includes the battery cell in the above embodiments or the battery in the above embodiments, and the battery cell 20 or the battery is used to provide electrical energy.

[0115] According to some embodiments of the present application, please refer to Figure 3 , Figure 4 , Figure 5 and Figure 6 , Figure 3 is a schematic cross-sectional structure diagram of the electrode assembly in the battery cell of some embodiments of the present application; Figure 4 is a cross-sectional view of the adhesive tape attached to the first electrode tab in some embodiments of the present application; Figure 5 is a schematic structural diagram of the adhesive tape on the first electrode tab after being folded in some embodiments of the present application; Figure 6Schematic diagram of a battery cell in a detection state on a bottom pallet according to some embodiments of the present application. The battery cell 20 includes an electrode assembly 22 and an adhesive tape 23. The electrode assembly 22 is of a wound structure. The electrode assembly 22 includes a first electrode tab 221, a second electrode tab 222, and a separator 24. The first electrode tab 221 and the second electrode tab 222 have opposite polarities. The separator 24 is disposed between the first electrode tab 221 and the second electrode tab 222. The adhesive tape 23 is attached to the bent section of the innermost circle of the first electrode tab 221. The adhesive tape 23 includes a base material 230, an adhesive layer 231, and contrast agent particles 235. The adhesive layer 231 is located on one side in the thickness direction of the base material 230. The contrast agent particles 235 are embedded in the adhesive layer 231. The base material 230 is a porous material. The base material 230 has a first surface in the thickness direction. The adhesive layer 231 is disposed on the first surface. The first surface includes an adhesive-applied area 2341 coated with the adhesive layer 231 and a blank area not coated with the adhesive layer 231.

[0116] Contrast agent particles are added to the adhesive layer 231. After the electrode assembly 22 is wound, the electrode assembly 22 is comprehensively detected by a contrast device (e.g., an X-ray detector 500). The X-ray detector 500 can image the adhesive tape 23 with contrast agent particles 235 inside the electrode assembly 22, and determine whether the adhesive tape 23 is folded according to the brightness color difference after imaging, so as to ensure that the electrode assembly 22 after the adhesive tape 23 is folded can be normally detected, reducing the risk of defective products flowing out and improving the yield rate of the battery cell 20.

[0117] On the one hand, through the adhesive layer 231 of the adhesive tape 23, it can be attached to the bent section of the innermost circle of the first electrode tab 221. The adhesive tape 23 can protect the bent section of the innermost circle of the first electrode tab 221, reducing the risk of cracking and powder falling off in the area of the first electrode tab 221 where the adhesive tape 23 is attached, thereby reducing the risk of the separator 24 being punctured during the cycling of the battery cell and causing short circuit of the positive and negative electrodes in contact.

[0118] On the other hand, when the base material 230 of the adhesive tape 23 is a porous material and the first surface of the base material 230 has a blank area not coated with the adhesive layer 231, during the charge and discharge process of the battery cell 20, active ions (e.g., lithium ions) can normally pass through the blank area of the adhesive tape 23 where the adhesive layer 231 is not provided. Compared with the case where the adhesive layer 231 is fully paved on the first surface of the base material 230, the area for active ions to pass through the adhesive tape 23 is increased, and the blocking effect of the adhesive tape 23 on the movement of active ions is reduced, so that the capacity of the area of the battery cell where the adhesive tape 23 is attached can be normally exerted. And because the active ions can normally pass through the adhesive tape 23, the active ions are not likely to accumulate at the edge of the adhesive tape 23, thereby reducing the risk of metal ions precipitating on the surface of the negative electrode tab.

[0119] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the various embodiments of the present application, and they should all be covered by the scope of the claims and the description of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed in the text, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery cell, characterized in that: include: An electrode assembly, comprising a first pole piece; The adhesive tape is attached to the first pole piece, and the adhesive tape comprises a substrate, an adhesive layer and contrast agent particles. The adhesive layer is located on one side of the substrate in the thickness direction, and the contrast agent particles are embedded in the adhesive layer.

2. The battery cell according to claim 1, characterized in that: The substrate is made of porous material.

3. The battery cell according to claim 2, characterized in that: The substrate has a first surface in a thickness direction, the adhesive layer is disposed on the first surface, and the first surface includes an adhesive coating area coated with the adhesive layer and a blank area not coated with the adhesive layer.

4. The battery cell according to claim 2, characterized in that: The porosity of the substrate is not less than 35% and not more than 65%.

5. The battery cell according to any one of claims 1 to 4, characterized in that: The electrode assembly is a wound structure, and further comprises a second pole piece and a diaphragm, wherein the first pole piece and the second pole piece have opposite polarities, and the diaphragm is disposed between the first pole piece and the second pole piece; Wherein, the adhesive tape is attached to at least one bending section of the first pole piece.

6. The battery cell according to claim 5, characterized in that: The adhesive tape is pasted on both sides of at least one of the bent sections of the first pole piece in the thickness direction.

7. The battery cell according to claim 5, characterized in that: The adhesive tape is attached to the innermost bending section of the first pole piece.

8. The battery cell according to claim 1, characterized in that: The first pole piece is a positive pole piece.

9. The battery cell according to claim 5, characterized in that: The first pole piece includes a first pole ear. In the width direction of the first pole piece, the diaphragm has a first edge corresponding to the first pole ear, and the first pole ear exceeds the first edge; the adhesive tape includes a first end portion corresponding to the first edge, and the first end portion does not exceed the first edge.

10. The battery cell according to claim 9, characterized in that: The diaphragm further includes a second edge disposed opposite to the first edge, and the adhesive tape includes a second end portion disposed corresponding to the second edge, and the second end portion exceeds the second edge.

11. A battery, characterized in that: The invention comprises a battery cell as claimed in any one of claims 1 to 10.

12. An electrical device, characterized in that: The invention comprises the battery cell according to any one of claims 1 to 10 or the battery according to claim 11, wherein the battery cell or the battery is used to provide electrical energy.

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