Battery cell, battery device, power-consuming device and battery cell manufacturing method

Abstract

The present application discloses a battery cell, a battery device, an electric device and a method for manufacturing a battery cell. The battery cell comprises: a shell having a receiving cavity; an electrode assembly arranged in the receiving cavity, the electrode assembly being wound along a winding direction by a laminate including a cathode electrode sheet and an anode electrode sheet, the cathode electrode sheet comprising a cathode current collector and a cathode active material layer, along the thickness direction of the cathode current collector, the cathode active material layer is arranged on two opposite surfaces of the cathode current collector, along the winding direction, at least one end of the cathode electrode sheet is provided with a first barrier layer, at least one of the two cathode active material layers at the same end of the cathode electrode sheet is provided with a first barrier layer, the surface of the cathode active material layer facing away from the cathode current collector is inwardly concave to form a concave portion, the first barrier layer is attached to the concave portion, and along the winding direction, the end face of at least one end of the cathode active material layer is attached with a second barrier layer. The present application can increase the battery capacity and reduce the risk of short circuit.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery cell, a battery device, an electrical device, and a method for manufacturing a battery cell. Background Art

[0002] New energy batteries are increasingly used in life and industry. For example, new energy vehicles equipped with batteries have been widely used. In addition, batteries are increasingly used in the field of energy storage. In new energy vehicles equipped with batteries, batteries can be used to provide power in whole or in part. In the field of energy storage, batteries can be installed in energy storage boxes or directly on the user side.

[0003] When a battery short-circuit occurs, it will cause the battery to heat up quickly and even cause fire and explosion. Therefore, how to reduce the risk of battery short-circuit is one of the topics that the industry needs to study. In addition, how to increase the battery capacity is also a topic that the industry has been studying. Summary of the invention

[0004] In order to solve the above technical problems, the present application provides a battery cell, a battery device, an electrical device and a battery cell manufacturing method having large battery capacity and low short circuit risk.

[0005] This application is implemented through the following technical solutions.

[0006] The first aspect of the present application provides a battery cell, comprising: a shell, the shell having a accommodating cavity; an electrode assembly, arranged in the accommodating cavity, the electrode assembly being formed by winding a stack including a cathode electrode sheet and an anode electrode sheet along a winding direction, the cathode electrode sheet comprising a cathode current collector and a cathode active material layer, along the thickness direction of the cathode current collector, the cathode active material layer is arranged on two opposite surfaces of the cathode current collector, along the winding direction, at least one end of the cathode electrode sheet is provided with a first barrier layer, at least one of the two cathode active material layers at the same end of the cathode electrode sheet is provided with the first barrier layer, the surface of the cathode active material layer facing away from the cathode current collector is recessed inward to form a recessed portion, and the first barrier layer is attached to the recessed portion; along the winding direction, a second barrier layer is attached to the end surface of at least one end of the cathode active material layer.

[0007] In the battery cell provided in the embodiment of the present application, the first barrier layer is attached to the recessed portion of the cathode active material layer, so that the height of the first barrier layer protruding from the surface of the cathode active material layer can be reduced or the first barrier layer does not protrude, thereby reducing the probability of cracking and powder loss of the pole piece due to the high protrusion of the first barrier layer, thereby increasing the capacity of the battery cell. Moreover, due to the provision of the recessed portion, the cathode active material at the coverage of the first barrier layer is reduced accordingly, so that the amount of lithium ions released can be reduced, thereby helping to reduce the probability of lithium precipitation and the probability of short circuit in the battery cell. The end face of the cathode active material layer is covered with a second barrier layer, which can prevent the active material on the end face covered by it from falling off, thereby further reducing the probability of powder loss at the cut end.

[0008] In some embodiments, the second barrier layer is further attached to an end surface of the cathode current collector along the winding direction.

[0009] In this way, the second barrier layer can not only prevent the end surface of the cathode active material layer from falling powder, but also prevent the end surface of the cathode current collector from falling metal debris, reducing the probability of metal debris piercing the separator, thereby reducing the probability of short circuit.

[0010] In some embodiments, the recessed portion extends along the winding direction to an edge of one end of the cathode active material layer close to the recessed portion, and the first barrier layer and the second barrier layer located at the same end of the cathode electrode sheet are connected.

[0011] The recessed portion extends along the winding direction to one end edge of the cathode active material layer close to the recessed portion, so that the recessed portion is closer to the end face of the cathode active material layer, and the first barrier layer is closer to the end face of the cathode active material layer. In addition, the first barrier layer and the second barrier layer are connected to more comprehensively block the surface of the cut end, thereby reducing the probability of powder falling off at the cut end to a greater extent.

[0012] In some embodiments, the two cathode active material layers at the same end of the cathode electrode sheet along the winding direction both have the recessed portion.

[0013] In this way, the first barrier layer is attached to both sides of the same end, further reducing the probability of powder falling off at the cut end.

[0014] In some embodiments, the two recessed portions located at the same end of the cathode electrode are respectively a first recessed portion and a second recessed portion, the first barrier layer attached to the first recessed portion and the first barrier layer attached to the second recessed portion are connected through a second barrier layer, and the second barrier layer is attached to the end surface of one end of the cathode electrode close to the first recessed portion and the second recessed portion along the winding direction.

[0015] In this way, the two connected first barrier layers and the second barrier layers cover the cut end of the cathode electrode piece tightly and block the surface of the cut end more comprehensively, thereby reducing the probability of powder falling off at the cut end to a greater extent.

[0016] In some embodiments, along a winding axis direction perpendicular to the winding direction, the recessed portion extends to two edges of the cathode active material layer respectively.

[0017] In this way, the area of ​​the concave portion is larger, the cathode active material at the cut end is further reduced, and the amount of lithium ions released is further reduced, which is conducive to reducing the probability of lithium precipitation and the probability of short circuit of the battery cell. In addition, the area of ​​the concave portion is larger, which is conducive to making the first barrier layer cover a larger area, further preventing the cut end of the cathode current collector from dropping metal debris and powder.

[0018] In some embodiments, the two recessed portions located at the same end of the cathode electrode sheet are respectively a first recessed portion and a second recessed portion, the first barrier layer attached to the first recessed portion has two ends along the winding axis that extend beyond two edges of the first recessed portion, the first barrier layer attached to the second recessed portion has two ends along the winding axis that extend beyond two edges of the second recessed portion, and the portion of the first barrier layer attached to the first recessed portion that extends beyond the edge of the first recessed portion is connected to the portion of the first barrier layer attached to the second recessed portion that extends beyond the edge of the second recessed portion.

[0019] In this way, the area of ​​the cathode active material layer covered by the first barrier layer is larger, and the first barrier layer covers the cut end more comprehensively, which can better reduce the probability of lithium plating. Moreover, the excess parts are connected to each other, which improves the reliability of the attachment between the first barrier layer and the cathode electrode and improves the effect of blocking metal debris and powder.

[0020] In some embodiments, a third barrier layer is provided at at least one end of the cathode electrode sheet along the winding direction, and the third barrier layer is attached to at least one of the two opposite end surfaces of the cathode electrode sheet along a winding axis perpendicular to the winding direction.

[0021] In this way, the end face of the cathode electrode along the winding axis is covered with a third barrier layer, which can prevent the active material and metal debris from falling off the end face covered by it, thereby greatly reducing the probability of powder and metal debris falling off at the cut end.

[0022] In some embodiments, the two recessed portions located at the same end of the cathode electrode are respectively a first recessed portion and a second recessed portion, and the first barrier layer attached to the first recessed portion and the first barrier layer attached to the second recessed portion are connected through the third barrier layer.

[0023] In this way, the two connected first barrier layers and the third barrier layer cover the cut end of the cathode electrode piece tightly, and block the surface of the cut end more comprehensively, thereby reducing the probability of powder falling off at the cut end to a greater extent.

[0024] In some embodiments, along the thickness direction of the cathode electrode, the depth of the recessed portion is not less than the thickness of the first barrier layer.

[0025] In this way, the first barrier layer does not protrude from the outer surface of the cathode electrode piece, which greatly reduces the probability of cracking and powder loss at the parts of the cathode electrode piece and the anode electrode piece corresponding to the protruding parts, and further improves the capacity of the battery cell.

[0026] In some embodiments, the first barrier layer includes a substrate layer and an adhesive layer attached to a surface of the substrate layer, and the substrate layer is bonded to the cathode plate through the adhesive layer.

[0027] In this way, the first barrier layer is attached to the recessed portion of the cathode active material layer by bonding, and the bonding operation is simple and efficient.

[0028] In some embodiments, the second barrier layer includes a substrate layer and an adhesive layer attached to a surface of the substrate layer, and the substrate layer is bonded to the cathode plate through the adhesive layer.

[0029] In this way, the second barrier layer is attached to the end surface of the cathode electrode sheet along the winding direction by bonding, and the bonding operation is simple and efficient.

[0030] In some embodiments, the third barrier layer includes a substrate layer and an adhesive layer attached to a surface of the substrate layer, and the substrate layer is bonded to the cathode plate through the adhesive layer.

[0031] In this way, the third barrier layer is attached to the end surface of the cut end of the cathode electrode piece along the winding axis by bonding, and the bonding operation is simple and efficient.

[0032] In some embodiments, the substrate layer is made of at least one of polyvinyl chloride, polyethylene, polypropylene, hexafluoropropylene-vinylidene fluoride copolymer, tetrafluoropropylene-vinylidene fluoride copolymer, trifluorochloropropylene-vinylidene fluoride copolymer, polyethylene terephthalate, polyimide, polyetherimide, polycarbonate, polystyrene, polyphenylene sulfide, polyvinylidene fluoride, polyvinylidene fluoride copolymer, polyarylate, fiber, nylon, and non-woven fabric.

[0033] The above materials are easy to obtain and have good toughness and strength, and can effectively reduce the probability of cracking of the pole piece or shedding of the active material.

[0034] In some embodiments, the adhesive layer is made of at least one of acrylic resin, acrylic acid-acrylate copolymer, butadiene-styrene copolymer, styrene-acrylic acid copolymer, styrene-acrylate copolymer, ethylene-vinyl acetate copolymer, acrylic acid grafted polyethylene, maleic anhydride grafted polyethylene, acrylic acid grafted polypropylene, maleic anhydride grafted polypropylene, polyvinylidene fluoride, carboxymethyl cellulose, polyimide, polyetherimide, polyethylene terephthalate, styrene-isoprene-styrene copolymer rubber, ethylene-vinyl acetate copolymer bisphenol A type epoxy resin, ethylene-vinyl acetate copolymer bisphenol F type epoxy resin, glycerol ether type epoxy resin, glycerol ester type epoxy resin, silicone type resin, polyurethane, and styrene-isoprene-styrene copolymer.

[0035] The above material is easy to obtain and has good adhesion, and can firmly adhere the base material layer to the inner surface of the recessed portion.

[0036] In some embodiments, a dimension of the first barrier layer along the winding direction is in the range of 5um to 10um.

[0037] In this way, by limiting the size of the first barrier layer along the winding direction within the range of 5um~10um, the size of the portion covered by the first barrier layer is made appropriate, so that the portion prone to powder loss is covered, reducing the probability of powder loss at the cut end, and the capacity of the battery cell will not be affected due to too large a covered area.

[0038] In some embodiments, the thickness of the first barrier layer is between 10 μm and 20 μm.

[0039] In this way, by limiting the thickness of the first barrier layer within the range of 10μm~20μm, the thickness of the first barrier layer is appropriate and can be attached to the recessed portion without protruding. Moreover, the toughness and strength of the first barrier layer in this thickness range are relatively high, which can greatly reduce the probability of cracking of the pole piece or shedding of the active material.

[0040] In some embodiments, along a winding axis perpendicular to the winding direction, a size of the first barrier layer is between 10 mm and 24 mm.

[0041] In this way, by limiting the size of the first barrier layer along the winding axis to the range of 10mm~24mm, the size of the first barrier layer is appropriate and can cover a sufficiently large area of ​​the cathode active material layer, thereby greatly reducing the probability of cracking of the pole piece or shedding of the active material.

[0042] A second aspect of the present application provides a battery device, comprising: at least the battery cell provided in the first aspect.

[0043] Since the battery device includes the battery cell provided by the first aspect, and the battery cell has a large battery capacity and a low short circuit risk, the battery device has a large battery capacity and a low short circuit risk.

[0044] A third aspect of the present application provides an electrical device, which includes the battery cell provided by the first aspect or the battery device provided by the second aspect for providing electrical energy.

[0045] Since the electrical device includes the battery cell provided in the first aspect or the battery device provided in the second aspect, and both the battery cell and the battery device have large battery capacity and low short circuit risk, the electrical device has large battery capacity and low short circuit risk.

[0046] A fourth aspect of the present application provides a method for manufacturing a battery cell, comprising:

[0047] Providing a cathode electrode sheet, an anode electrode sheet, a first barrier layer and a second barrier layer,

[0048] The cathode electrode sheet comprises a cathode current collector and a cathode active material layer, and along the thickness direction of the cathode current collector, the cathode active material layer is arranged on two opposite surfaces of the cathode current collector;

[0049] Attaching the first barrier layer and the second barrier layer to the feeding end of the cathode electrode sheet;

[0050] Winding the cathode electrode sheet and the anode electrode sheet along a winding direction;

[0051] Cutting the cathode electrode sheet, and attaching the first barrier layer and the second barrier layer to the rolled end of the cathode electrode sheet to form an electrode assembly;

[0052] Providing a housing, and placing the electrode assembly into a receiving cavity of the housing to form a battery cell;

[0053] Among them, along the winding direction, at least one of the two cathode active material layers at the same end of the cathode electrode sheet is provided with the first barrier layer, the surface of the cathode active material layer facing away from the cathode current collector is recessed inward to form a recessed portion, and the first barrier layer is attached to the recessed portion, and along the winding direction, the second barrier layer is attached to the end face of the cathode active material layer.

[0054] In the battery cell manufactured by the battery cell manufacturing method provided by the embodiment of the present application, the first barrier layer is attached to the recessed portion of the cathode active material layer, so that the height of the first barrier layer protruding from the surface of the cathode active material layer can be reduced or the first barrier layer does not protrude, thereby reducing the probability of cracking and powder loss of the pole piece due to the high protrusion of the first barrier layer, thereby increasing the capacity of the battery cell. Moreover, due to the provision of the recessed portion, the cathode active material at the coverage of the first barrier layer is reduced accordingly, so that the amount of lithium ion escape can be reduced, thereby helping to reduce the probability of lithium precipitation and the probability of short circuit in the battery cell. The end face of the cathode active material layer is covered with a second barrier layer, which can prevent the active material on the end face covered by it from falling off, thereby further reducing the probability of powder loss at the cut end.

[0055] The beneficial effects of the embodiments of the present disclosure include: through the present application, a battery cell, a battery device, an electrical device and a battery cell manufacturing method with large battery capacity and low short circuit risk are provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0057] Figure 1 is a schematic structural diagram of a vehicle according to one or more embodiments;

[0058] Figure 2 is a schematic structural diagram of a battery pack according to one or more embodiments;

[0059] Figure 3 is a schematic structural diagram of a battery cell according to one or more embodiments;

[0060] Figure 4 is a schematic structural diagram of an electrode assembly according to one or more embodiments;

[0061] Figure 5 for Figure 4 The enlarged view of point A in the middle;

[0062] Figure 6 is a schematic diagram of a partial structure of a negative electrode sheet according to one or more embodiments;

[0063] Figure 7 for Figure 5 A top view of one structure of the portion shown;

[0064] Figure 8 for Figure 5A top view of another configuration of the portion shown;

[0065] Fig. 9 is a flow chart of a method for manufacturing a battery cell according to one or more embodiments.

[0066] Description of Reference Numerals

[0067] 1000 vehicle; 100 battery pack; 10 battery box; 101 box cover; 102 box body; 200 controller; 300 motor;

[0068] 20 battery cell; 1 outer shell; 11 end cover; 12 shell; 2 electrode assembly; 21 cathode pole piece; 211 cathode current collector; 2111 second end surface; 212 cathode active material layer; 2121 first end surface; 213 recessed portion; 213a first recessed portion; 213b second recessed portion; 22 anode pole piece; 23 blocking member; 231 first blocking layer; 232 second blocking layer; 233 third blocking layer; 24 separator; 25 pole ear; 3 pressure relief mechanism; 4 pole column. DETAILED DESCRIPTION

[0069] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0070] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification of this application and the above-mentioned drawings and any variations thereof are intended to cover non-exclusive inclusions.

[0071] In the description of the embodiments of the present application, the technical terms "first", "second", "third", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0072] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0073] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0074] In the description of the embodiments of the present application, the orientation or position relationship indicated by technical terms such as "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", and "circumferential" are based on the orientation or position relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed, operated or used in a specific orientation. Therefore, they should not be understood as limitations on the embodiments of the present application.

[0075] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0076] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, the technical term "contact" should be understood in a broad sense, and may be direct contact or contact through an intermediate medium layer. It may be contact with essentially no interaction force between the two contacting parties, or it may be contact with interaction force between the two contacting parties.

[0077] Below, this application is described in detail.

[0078] At present, new energy batteries are increasingly used in life and industry. New energy batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but are also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric cars, as well as aerospace and other fields. With the continuous expansion of the application field of power batteries, the market demand is also constantly expanding.

[0079] The battery cell includes an electrode assembly and an electrolyte, and the electrode assembly includes a cathode electrode sheet, an anode electrode sheet and a separator. The battery cell mainly relies on the movement of metal ions between the cathode electrode sheet and the anode electrode sheet to work. The cathode electrode sheet includes a cathode current collector and a cathode active material layer, and the cathode active material layer is coated on the surface of the cathode current collector; the cathode current collector includes a cathode current collector and a cathode protrusion protruding from the cathode current collector, the cathode current collector is coated with a cathode active material layer, at least part of the cathode protrusion is not coated with the cathode active material layer, and the cathode protrusion serves as a cathode tab. Taking a lithium-ion battery as an example, the material of the cathode current collector may be aluminum, and the cathode active material layer includes a cathode active material, and the cathode active material may be lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganate, etc. The anode electrode sheet includes an anode current collector and an anode active material layer, and the anode active material layer is coated on the surface of the anode current collector; the anode current collector includes an anode current collector and an anode protrusion protruding from the anode current collector, the anode current collector is coated with an anode active material layer, at least part of the anode protrusion is not coated with the anode active material layer, and the anode protrusion serves as an anode tab. The material of the anode current collector may be copper, and the anode active material layer includes an anode active material, which may be carbon or silicon, etc. In order to ensure that a large current passes without melting, the number of cathode tabs is multiple and stacked together, and the number of anode tabs is multiple and stacked together. In addition, the electrode assembly may be a wound structure, but the embodiments of the present application are not limited thereto.

[0080] When a lithium-ion battery cell is charging, lithium ions are released from the cathode active material layer and embedded in the anode active material layer. However, some abnormal situations may occur. For example, too many lithium ions are released from the cathode active material layer, while the anode active material layer has insufficient lithium embedding space, the resistance of lithium ions embedding in the anode active material layer is too large, or the lithium ions are released from the cathode active material layer too quickly. The released lithium ions cannot be embedded in the anode active material layer of the anode pole piece in equal amounts. The lithium ions that cannot be embedded in the anode pole piece can only obtain electrons on the surface of the anode pole piece, thereby forming metallic lithium. This is the lithium plating phenomenon. Lithium plating not only reduces the performance of lithium-ion battery cells and significantly shortens the cycle life, but also limits the fast charging capacity of lithium-ion battery cells. When lithium plating is severe, the released lithium ions can form lithium crystals on the surface of the anode pole piece, and the lithium crystals can easily puncture the separator, causing the risk of short circuit between adjacent cathode pole pieces and anode pole pieces.

[0081] In the battery assembly, the cathode and anode pole pieces are prone to cracking and powdering at the cut ends along the winding direction. In order to reduce the probability of cracking and powdering, in the prior art, a barrier layer is pasted on the cut ends of the cathode pole pieces that are prone to powdering and aluminum leakage, so as to reduce the probability of powdering and aluminum leakage through physical isolation. However, pasting the barrier layer brings the following problems: First, the pasted barrier layer protrudes a certain height from the cathode active material layer, which causes the position to crack and powdering at the position of the raised edge of the barrier layer corresponding to the cathode pole piece and the anode pole piece after undergoing a hot pressing process or aging due to local stress extrusion, thereby affecting the battery capacity. Second, the barrier layer covers a portion of the cathode active layer, which can theoretically prevent the cathode from de-lithiation at the covered position. However, in fact, the barrier layer cannot achieve complete electrochemical isolation and cannot completely prevent the lithium ions from the cathode active particles at the covered position from escaping. The anode at the position corresponding to the barrier layer has limited lithium embedding capacity, which can easily lead to the precipitation of lithium metal on the surface of the anode electrode, that is, the phenomenon of edge lithium precipitation, which may lead to puncture of the diaphragm and cause short circuit problems in the battery cell.

[0082] To solve the above problems, the present application can reduce the thickness of the barrier layer of the cathode active material layer of the cathode electrode, so that the height of the barrier layer protrusion can be reduced or not protruded, thereby reducing the probability of cracking and powder loss of the electrode due to the protrusion of the barrier layer, thereby improving the battery capacity. Moreover, since the barrier layer of the cathode active material layer is thinned, the cathode active material covered by the barrier layer is reduced accordingly, so the amount of lithium ions released can be reduced, which is conducive to reducing the probability of lithium precipitation and the probability of short circuit of the battery cell.

[0083] Based on such a design concept, the inventor of the present application designed a battery cell, which includes a shell and an electrode assembly, the shell having a accommodating cavity; the electrode assembly is arranged in the accommodating cavity, and the electrode assembly is formed by winding a stack including a cathode electrode sheet and an anode electrode sheet along a winding direction, the cathode electrode sheet includes a cathode current collector and a cathode active material layer, and along the thickness direction of the cathode current collector, the cathode active material layer is arranged on two opposite surfaces of the cathode current collector, along the winding direction, at least one end of the cathode electrode sheet is provided with a first barrier layer, and at least one of the two cathode active material layers at the same end of the cathode electrode sheet is provided with the first barrier layer, and the surface of the cathode active material layer facing away from the cathode current collector is recessed inward to form a recessed portion, and the first barrier layer is attached to the recessed portion.

[0084] The first barrier layer is attached to the concave portion of the cathode active material layer, so that the height of the protrusion of the first barrier layer can be reduced or the first barrier layer does not protrude, thereby reducing the probability of cracking and powder loss of the pole piece caused by the protrusion of the first barrier layer, thereby increasing the battery capacity. Moreover, due to the setting of the concave portion, the cathode active material covered by the first barrier layer is correspondingly reduced, so that the amount of lithium ions released can be reduced, which is conducive to reducing the probability of lithium precipitation and the probability of short circuit of the battery cell.

[0085] The battery cells provided in the embodiment of the present application can be grouped into a battery cell assembly to provide voltage and capacity. The multiple battery cells of the battery cell assembly can be connected in series, in parallel or in mixed connection through a busbar component.

[0086] The battery cell provided in the embodiment of the present application can be applied to a battery device, and the battery device (Battery Apparatus) may include one or more battery cell assemblies for providing voltage and capacity. The battery cell assembly (Battery Cell Assembly) may include multiple battery cells, and the multiple battery cells are connected in series, parallel or mixed through a busbar component.

[0087] In some embodiments, a battery cell assembly is generally formed by arranging a plurality of battery cells; as an example, a battery cell assembly may be a battery module, and a battery module is formed by arranging and fixing a plurality of battery cells to form an independent module. As an example, a battery module may be formed by bundling a plurality of battery cells by a cable tie.

[0088] In some embodiments, the battery device may be a battery pack, which includes a battery box and one or more battery cell assemblies, wherein the battery cell assemblies are accommodated in the battery box.

[0089] As an example, the battery cell assembly may be a battery module, and the battery cell assembly may be accommodated in a battery box by fixing the battery module in the battery box.

[0090] As an example, the battery cell assembly may also be housed in the battery box by directly fixing a plurality of battery cells to the battery box.

[0091] In some embodiments, the battery device refers to an energy storage device, which includes a battery box, at least one side of which is provided with a door. The energy storage device includes an energy storage container, an energy storage cabinet, and the like.

[0092] The technical solutions described in the embodiments of the present application are applicable to various electrical devices using battery cells and battery devices, such as mobile phones, portable devices, laptop computers, electric vehicles, electric toys, electric tools, vehicles, ships and spacecraft, for example, spacecraft include airplanes, rockets, space shuttles and spacecraft, etc.

[0093] In the following embodiments, for the convenience of description, an electric device according to an embodiment of the present application is taken as an example of a vehicle 1000. The following is a description with reference to the accompanying drawings.

[0094] Figure 1 is a schematic diagram of the structure of a vehicle according to one or more embodiments.

[0095] The vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended range vehicle. Figure 1 As shown, a battery pack 100 is disposed inside the vehicle 1000, and the battery pack 100 can be disposed at the bottom, head, or tail of the vehicle 1000. The battery pack 100 can be used to power the vehicle 1000, for example, the battery pack 100 can be used as an operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300, and the controller 200 is used to control the battery pack 100 to power the motor 300, for example, for the starting, navigation, and working power requirements of the vehicle 1000 during driving.

[0096] In some embodiments of the present application, the battery pack 100 can not only serve as the operating power source of the vehicle 1000, but also serve as the driving power source of the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0097] Figure 2 is a schematic structural diagram of a battery pack 100 according to one or more embodiments.

[0098] like Figure 2 As shown, the battery pack 100 includes a battery box 10 and at least one battery cell 20. The battery box 10 is provided with a receiving space, and the at least one battery cell 20 is received in the receiving space.

[0099] In some embodiments of the present application, the battery box 10 includes a box body 102 and a box cover 101 , and the box cover 101 covers the box body 102 , so that the accommodating space is formed between the box body 102 and the box cover 101 .

[0100] The box body 102 may be a hollow structure with one end open, and the box cover 101 may be a plate-like structure, and the box cover 101 covers the open side of the box body 102, so that the box cover 101 and the box body 102 jointly define a storage space; the box cover 101 and the box body 102 may also be hollow structures with one side open, and the open side of the box cover 101 covers the open side of the box body 102. Of course, the battery box 10 formed by the box cover 101 and the box body 102 may be in various shapes, such as a cylinder, a cuboid, etc.

[0101] In the battery pack 100, there can be multiple battery cells 20, and the multiple battery cells 20 can be connected in series, in parallel, or in a mixed connection. The mixed connection means that the multiple battery cells 20 are both connected in series and in parallel. The multiple battery cells 20 can be directly connected in series, in parallel, or in a mixed connection, and then the whole formed by the multiple battery cells 20 is placed in the accommodation space formed by the box body 102 and the box cover 101; of course, the battery pack 100 can also be a battery module formed by connecting multiple battery cells 20 in series, in parallel, or in a mixed connection, and then the multiple battery modules are connected in series, in parallel, or in a mixed connection to form a whole, and are accommodated in the accommodation space formed by the box body 102 and the box cover 101. The battery pack 100 can also include other structures. For example, the battery pack 100 can also include a busbar component for realizing electrical connection between the multiple battery cells 20.

[0102] In the embodiment of the present application, the battery cell 20 may be a secondary battery. A secondary battery refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0103] The battery cell 20 can be 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 storage battery, etc., which is not limited in the embodiments of the present application.

[0104] The battery cell 20 may be a cylindrical battery cell, a prismatic battery cell or a battery cell of other shapes. Prismatic battery cells include square shell battery cells, blade-shaped battery cells, and polygonal prismatic batteries. Polygonal prismatic batteries are, for example, hexagonal prismatic batteries, etc. This application has no particular limitation.

[0105] Below, refer to Figures 3 to 9 Some embodiments of the present application are described in detail.

[0106] Figure 3 is a schematic structural diagram of a battery cell according to one or more embodiments; Figure 4 is a schematic structural diagram of an electrode assembly according to one or more embodiments; Figure 5 for Figure 4 The enlarged view of point A in the middle; Figure 6 is a schematic diagram of a partial structure of a negative electrode sheet according to one or more embodiments; Figure 7 for Figure 5 A top view of one structure of the portion shown; Figure 8 for Figure 5 A top view of another configuration of the portion shown; Fig. 9 is a flow chart of a method for manufacturing a battery cell according to one or more embodiments.

[0107] In the description of the embodiments of the present application, for the sake of convenience, the direction of arrow C indicates the winding direction of the cathode electrode sheet 21 and the anode electrode sheet 22 in the electrode assembly 2, and the direction of arrow X indicates the winding axis perpendicular to the winding direction C.

[0108] In a first aspect, the present application provides a battery cell 20, such as Figures 3 to 7 As shown, the battery cell 20 includes a shell 1 and an electrode assembly 2, the shell 1 has a accommodating cavity; the electrode assembly 2 is arranged in the accommodating cavity, and the electrode assembly 2 is formed by winding a stack including a cathode electrode sheet 21 and an anode electrode sheet 22 along a winding direction C, the cathode electrode sheet 21 includes a cathode current collector 211 and a cathode active material layer 212, along the thickness direction of the cathode current collector 211, the cathode active material layer 212 is arranged on two opposite surfaces of the cathode current collector 211, along the winding direction C, at least one end of the cathode electrode sheet 21 is provided with a first barrier layer 231, at least one of the two cathode active material layers 212 at the same end of the cathode electrode sheet 21 is provided with the first barrier layer 231, and the surface of the cathode active material layer 212 facing away from the cathode current collector 211 is recessed inward to form a recessed portion 213, and the first barrier layer 231 is attached to the recessed portion 213.

[0109] The shell 1 is a shell-like structure for encapsulating the electrode assembly 2 and the electrolyte, etc. The shell 1 can be a steel shell, an aluminum shell, a plastic shell (such as polypropylene), a composite metal shell (such as a copper-aluminum composite shell) or an aluminum-plastic film, etc. The shell 1 can be of various shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, a hexagonal prism shape, etc. Specifically, the shape of the shell 1 can be determined according to the specific shape and size of the electrode assembly 2. The material of the shell 1 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiment of the present application does not impose any special restrictions on this. The accommodating cavity of the shell 1 can contain one or more electrode assemblies 2.

[0110] In some embodiments, the electrode assembly 2 also includes a separator 24 disposed between the cathode electrode piece 21 and the anode electrode piece 22, and the separator 24 can prevent the cathode and the anode from short-circuiting, and at the same time allow active ions to pass through. In some embodiments, the separator is a separator. The present application has no particular restrictions on the type of separator, and any known porous structure separator with good chemical stability and mechanical stability can be selected. As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride, and ceramics. In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive electrode and the negative electrode, and at the same time plays the role of transmitting ions and isolating the positive and negative electrodes.

[0111] In the embodiment of the present application, the winding direction C is the direction in which the cathode electrode sheet 21 and the anode electrode sheet 22 are wound from the inside to the outside. Figure 4 In the figure, the winding direction C is clockwise. The two ends along the winding direction C may refer to the two ends of the length direction of the pole piece after the pole piece is unfolded; the winding direction C may also refer to the direction intersecting with the height direction and thickness direction of the pole piece when the battery cell is placed vertically.

[0112] The surface of the cathode active material layer 212 facing away from the cathode current collector 211 has a recessed portion 213 formed at only one end along the winding direction C, or at both ends of the cathode active material layer 212 along the winding direction C.

[0113] The recessed portion 213 may extend to one end edge of the cathode active material layer 212 close to the recessed portion 213 along the winding direction C, or may not extend to one end edge of the cathode active material layer 212 close to the recessed portion 213. Along the winding axial direction X perpendicular to the winding direction C, both ends of the recessed portion 213 may extend to two edges of the cathode active material layer 212 respectively, or may extend to one edge of the cathode active material layer 212 only at one end along the winding axial direction X, or may not extend to the edge of the cathode active material layer 212 at both ends along the winding axial direction X.

[0114] The first barrier layer 231 may be provided at both ends of the cathode electrode sheet 21 along the winding direction C, or only at one end. The end of the cathode electrode sheet 21 provided with the first barrier layer 231 may have both cathode active material layers 212 at the end attached with the first barrier layer 231, or only one cathode active material layer 212 at the end attached with the first barrier layer 231.

[0115] In some embodiments, attaching refers to bonding or coating or spraying.

[0116] The first barrier layer 231 is attached to the recessed portion 213 , and the first barrier layer 231 may cover the entire inner surface of the recessed portion 213 , or may only cover a portion of the inner surface of the recessed portion 213 .

[0117] The first barrier layer 231 is a layered body that blocks the outside of the cathode active material layer 212. The first barrier layer 231 is attached to the inner surface of the recessed portion 213, which can reduce the probability of cracking and powder loss of the cathode active material layer 212 in the covered area. Since the recessed portion 213 is recessed inward, the height of the first barrier layer 231 attached to the recessed portion 213 protruding from the outer surface of the cathode active material layer 212 can be reduced, or the first barrier layer 231 does not protrude from the surface of the cathode active material layer 212.

[0118] In the battery cell 20 provided in the embodiment of the present application, the first barrier layer 231 is attached to the recessed portion 213 of the cathode active material layer 212, so that the height of the first barrier layer 231 protruding from the surface of the cathode active material layer 212 can be reduced or the first barrier layer 231 does not protrude, thereby reducing the probability of cracking and powder loss of the pole piece due to the high protrusion of the first barrier layer 231, thereby improving the capacity of the battery cell 20. Moreover, due to the setting of the recessed portion 213, the cathode active material covered by the first barrier layer 231 is correspondingly reduced, so that the amount of lithium ions released can be reduced, which is conducive to reducing the probability of lithium precipitation and the probability of short circuit in the battery cell 20.

[0119] In some embodiments of the present application, Figure 3 As shown, the outer shell 1 includes an end cover 11 and a shell 12, the shell 12 has a accommodating cavity and an opening, the electrode assembly 2 is arranged in the accommodating cavity, the end cover 11 closes the opening of the shell 12, and a pole 4 is arranged on any wall surface of the end cover 11 or the shell 12. The pole 4 is connected to the pole ear 25 of the electrode assembly 2 for inputting or outputting electric energy.

[0120] The end cap 11 refers to a component that covers the opening of the shell 12 to isolate the internal environment of the battery cell 20 from the external environment. Without limitation, the shape of the end cap 11 can be adapted to the shape of the shell 12 to match the shell 12. Optionally, the end cap 11 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that the end cap 11 is not easily deformed when squeezed and collided, so that the battery cell 20 can have a higher structural strength and the safety performance can also be improved. The pole 4 is electrically connected to the electrode assembly 2 for outputting or inputting the electrical energy of the battery cell 20.

[0121] In some embodiments of the present application, Figure 3As shown, the end cover 11 may also be provided with a pressure relief mechanism 3 for releasing the internal pressure when the internal pressure or temperature of the battery cell 20 reaches a threshold value, and a pressure relief mechanism protection patch is affixed to the outside of the pressure relief mechanism 3. The material of the end cover 11 may also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiments of the present application do not impose any special restrictions on this. In some embodiments of the present application, an insulating structure may also be provided on the inner side of the end cover 11, and the insulating structure may be used to isolate the electrical connection components in the housing 12 from the end cover 11 to reduce the risk of short circuit. Exemplarily, the insulating structure may be plastic, rubber, etc.

[0122] The shell 12 is a component used to cooperate with the end cap 11 to form the internal environment of the battery cell 20, wherein the formed internal environment can be used to accommodate the electrode assembly 2, the electrolyte and other components. The shell 12 and the end cap 11 can be independent components, and an opening can be set on the shell 12, and the internal environment of the battery cell 20 is formed by covering the opening with the end cap 11 at the opening. Without limitation, the end cap 11 and the shell 12 can also be integrated. Specifically, the end cap 11 and the shell 12 can form a common connection surface before other components are put into the shell, and when the interior of the shell 12 needs to be encapsulated, the end cap 11 is covered with the shell 12. The shell 12 can be of various shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, a hexagonal prism, etc. Specifically, the shape of the shell 12 can be determined according to the specific shape and size of the electrode assembly 2. The material of the shell 12 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiment of the present application does not impose any special restrictions on this.

[0123] In some embodiments, both ends of the cathode electrode sheet 21 along the winding direction C are provided with a first barrier layer 231. In some embodiments, the feeding end of the cathode electrode sheet 21 rolled into the innermost circle of the electrode assembly 2 is provided with a first barrier layer 231, and the winding end located at the outermost circle is not provided with a first barrier layer 231. In some embodiments, the feeding end of the cathode electrode sheet 21 rolled into the innermost circle of the electrode assembly 2 is not provided with a first barrier layer 231, and the winding end located at the outermost circle is provided with a first barrier layer 231.

[0124] In some embodiments of the present application, Figure 5 As shown, along the winding direction C, a second barrier layer 232 is attached to an end surface of at least one end of the cathode active material layer 212 .

[0125] The second barrier layer 232 may cover part of the end surface of the cathode active material layer 212, or may cover the entire end surface of the cathode active material layer 212. Both end surfaces of the cathode active material layer 212 along the winding direction C are covered with the second barrier layer 232, or one end surface of the cathode active material layer 212 along the winding direction C is covered with the second barrier layer 232.

[0126] In this way, the end surface of the cathode active material layer 212 is covered with the second barrier layer 232, which can prevent the active material on the end surface covered by the second barrier layer 232 from falling off, thereby further reducing the probability of powder falling off at the cut end.

[0127] In some embodiments of the present application, Figure 5 and Figure 6 As shown, the recessed portion 213 extends along the winding direction C to an edge of the cathode active material layer 212 close to the recessed portion 213 , and the first barrier layer 231 and the second barrier layer 232 located at the same end of the cathode electrode sheet 21 are connected.

[0128] The recessed portion 213 extends along the winding direction C to one end edge of the cathode active material layer 212 close to the recessed portion 213, so that the recessed portion 213 is closer to the end surface of the cathode active material layer 212, and the first barrier layer 231 is closer to the end surface of the cathode active material layer 212. In addition, the first barrier layer 231 and the second barrier layer 232 are connected to more comprehensively block the surface of the cut end, thereby reducing the probability of powder falling off at the cut end to a greater extent.

[0129] In some embodiments of the present application, the first barrier layer 231 and the second barrier layer 232 are not connected.

[0130] In some embodiments of the present application, Figure 5 As shown, the second barrier layer 232 is also attached to one end surface of the cathode current collector 211 along the winding direction C.

[0131] For example, Figure 6 As shown, one end face of the cathode active material layer 212 along the winding direction C is a first end face 2121, and one end face of the cathode current collector 211 along the winding direction C is a second end face 2111. The first end face 2121 and the second end face 2111 are located at the same end of the cathode electrode sheet 21. Figure 5 As shown, the second barrier layer 232 is attached to the first end surface 2121 and the second end surface 2111 , and the second barrier layer 232 is connected to the first barrier layer 231 .

[0132] In this way, the second barrier layer 232 can not only prevent the end surface of the cathode active material layer 212 from falling powder, but also prevent the end surface of the cathode current collector 211 from falling metal debris, thereby reducing the probability of metal debris piercing the separator 24, thereby reducing the probability of short circuit.

[0133] In some embodiments of the present application, Figure 5 and Figure 6 As shown, the two cathode active material layers 212 at the same end of the cathode electrode sheet 21 along the winding direction C both have a recessed portion 213 .

[0134] The two cathode active material layers 212 at the same end of the cathode electrode 21 along the winding direction C both have a recessed portion 213, and a first barrier layer 231 is attached to the recessed portion 213, that is, the two cathode active material layers 212 at the same end of the cathode electrode 21 along the winding direction C both have a first barrier layer 231 attached to them.

[0135] In this way, the first barrier layer 231 is attached to both sides of the same end, further reducing the probability of powder falling off at the cut end.

[0136] In some embodiments of the present application, Figure 5 and Figure 6 As shown, the two recessed portions 213 located at the same end of the cathode electrode 21 are respectively a first recessed portion 213a and a second recessed portion 213b, and the first barrier layer 231 attached to the first recessed portion 213a and the first barrier layer 231 attached to the second recessed portion 213b are connected through a second barrier layer 232, and the second barrier layer 232 is attached to the end surface of the cathode electrode 21 along the winding direction C close to one end of the first recessed portion 213a and the second recessed portion 213b.

[0137] For example, Figure 5 As shown, the first barrier layer 231 attached to the first recessed portion 213a, the first barrier layer 231 attached to the second recessed portion 213b, and the second barrier layer 232 connected between the two first barrier layers 231 form an integrally formed barrier member 23, that is, one end of the barrier member 23 is attached to a first recessed portion 213a, the barrier member 23 bypasses and is attached to the end surface of the cathode electrode 21, and the other end of the barrier member 23 is attached to another first recessed portion 213a.

[0138] In this way, the two connected first barrier layers 231 and the second barrier layer 232 cover the cut end of the cathode electrode piece 21 tightly, and more comprehensively block the surface of the cut end, thereby reducing the probability of powder falling off at the cut end to a greater extent.

[0139] In some embodiments of the present application, recessed portions 213 are provided on two opposite surfaces of the cathode electrode piece 21 at both ends along the winding direction C, and the two recessed portions 213 located at the same end of the cathode electrode piece 21 and the end surface of the end are attached to the same blocking member 23, and the blocking member 23 includes two first blocking layers 231 and a second blocking layer 232 connected between the two first blocking layers 231, the two first blocking layers 231 are respectively attached to the two recessed portions 213, and the second blocking layer 232 is attached to the end surface of the cathode electrode piece 21.

[0140] In this way, the two cut ends of the cathode electrode piece 21 are covered by the blocking member 23, which can prevent the cut end of the cathode current collector 211 from dropping metal debris and powder to a greater extent. In addition, the cathode electrode piece 21 is provided with more recessed parts 213, so that the cathode active material at the two cut ends of the cathode electrode piece 21 is reduced accordingly, which can reduce the amount of lithium ions released, thereby helping to reduce the probability of lithium precipitation, and calmly reduce the probability of short circuit of the battery cell 20.

[0141] In some embodiments of the present application, along a winding axis X perpendicular to the winding direction C, the recessed portion 213 extends to two edges of the cathode active material layer 212 .

[0142] In this way, the area of ​​the recessed portion 213 is larger, the cathode active material at the cut end is further reduced, and the amount of lithium ions released is further reduced, which is conducive to reducing the probability of lithium precipitation and the probability of short circuit of the battery cell 20. In addition, the area of ​​the recessed portion 213 is larger, which is conducive to making the first barrier layer 231 cover a larger area, further preventing the cut end of the cathode current collector 211 from falling metal debris and powder.

[0143] In some embodiments of the present application, both ends of the first barrier layer 231 attached to the first recessed portion 213a along the winding axis X respectively extend beyond the two edges of the first recessed portion 213a, and both ends of the first barrier layer 231 attached to the second recessed portion 213b along the winding axis X respectively extend beyond the two edges of the second recessed portion 213b, and the portion of the first barrier layer 231 attached to the first recessed portion 213a that extends beyond the edge of the first recessed portion 213a is connected to the portion of the first barrier layer 231 attached to the second recessed portion 213b that extends beyond the edge of the second recessed portion 213b.

[0144] In this way, the area of ​​the cathode active material layer 212 covered by the first barrier layer 231 is larger, and the first barrier layer 231 covers the cut end more comprehensively, which can better reduce the probability of lithium plating. Moreover, the excess parts are connected to each other, which improves the reliability of the attachment between the first barrier layer 231 and the cathode electrode 21 and improves the effect of blocking metal debris and powder.

[0145] In some embodiments of the present application, both ends of the first barrier layer 231 attached to the first recessed portion 213a along the winding axis X respectively extend beyond the two edges of the first recessed portion 213a, and both ends of the first barrier layer 231 attached to the second recessed portion 213b along the winding axis X respectively extend beyond the two edges of the second recessed portion 213b, and the portion of the first barrier layer 231 attached to the first recessed portion 213a that extends beyond the edge of the first recessed portion 213a and the portion of the first barrier layer 231 attached to the second recessed portion 213b that extends beyond the edge of the second recessed portion 213b are bonded to each other.

[0146] In this way, the area of ​​the cathode active material layer 212 covered by the first barrier layer 231 is larger, and the first barrier layer 231 covers the cut end more comprehensively, which can better reduce the probability of lithium deposition. Moreover, the excess parts are bonded to each other, which improves the reliability of the attachment of the first barrier layer 231 to the cathode electrode 21 and improves the effect of blocking metal debris and powder. Moreover, the excess parts of the two first barrier layers 231 are connected to each other, which can reduce the interference of the excess parts with the isolation member 24 and the anode electrode 22.

[0147] In some embodiments of the present application, Figure 8 As shown, at least one end of the cathode electrode piece 21 along the winding direction C is provided with a third barrier layer 233 , and along the winding axis X perpendicular to the winding direction C, at least one of the two opposite end surfaces of the cathode electrode piece 21 is attached with the third barrier layer 233 .

[0148] In this way, the end face of the cathode electrode 21 along the winding axis X is covered with the third barrier layer 233, which can prevent the active material and metal debris from falling off the end face covered by it, thereby further reducing the probability of powder and metal debris falling off at the cut end.

[0149] In some embodiments of the present application, the two recessed portions 213 located at the same end of the cathode electrode 21 are respectively a first recessed portion 213a and a second recessed portion 213b, and the first barrier layer 231 attached to the first recessed portion 213a and the first barrier layer 231 attached to the second recessed portion 213b are connected through the first barrier layer 231.

[0150] In this way, the two connected first barrier layers 231 and the third barrier layer 233 cover the cut end of the cathode electrode piece 21 tightly, and block the surface of the cut end more comprehensively, thereby reducing the probability of powder falling off at the cut end to a greater extent.

[0151] In some embodiments of the present application, the first barrier layer 231 and the first barrier layer 231 are not connected.

[0152] In some embodiments of the present application, along the thickness direction of the cathode electrode piece 21 , the depth of the recessed portion 213 is not less than the thickness of the first barrier layer 231 .

[0153] In this way, the first barrier layer 231 does not protrude from the outer surface of the cathode electrode sheet 21 , thereby reducing the probability of cracking and powdering at the portions of the cathode electrode sheet 21 and the anode electrode sheet 22 corresponding to the protruding portions, and further improving the capacity of the battery cell 20 .

[0154] Exemplarily, the depth of the recessed portion 213 along the thickness direction of the cathode electrode piece 21 is equal to the thickness of the first barrier layer 231, so that the outer surface of the first barrier layer 231 is flush with the outer surface of the cathode active material layer 212 of the cathode electrode piece 21. In this way, there is no protruding structure on the outer surface of the cathode electrode piece 21, which better reduces the probability of problems such as electrode cracking and powder loss caused by local stress caused by the protruding structure.

[0155] In some embodiments of the present application, the first barrier layer 231 includes a substrate layer and an adhesive layer attached to a surface of the substrate layer, and the substrate layer is bonded to the cathode electrode 21 through the adhesive layer.

[0156] In this way, the first barrier layer 231 is attached to the recessed portion 213 of the cathode active material layer 212 by bonding, and the bonding operation is simple and efficient.

[0157] In some embodiments of the present application, the second barrier layer 232 includes a substrate layer and an adhesive layer attached to a surface of the substrate layer, and the substrate layer is bonded to the cathode electrode 21 through the adhesive layer.

[0158] In this way, the second barrier layer 232 is attached to the end surface of the cathode electrode 21 along the winding direction C by bonding, and the bonding operation is simple and efficient.

[0159] In some embodiments of the present application, the third barrier layer 233 includes a substrate layer and an adhesive layer attached to a surface of the substrate layer, and the substrate layer is bonded to the cathode electrode 21 through the adhesive layer.

[0160] In this way, the third barrier layer 233 is attached to the end surface of the cut end of the cathode electrode piece 21 along the winding axis X by bonding, and the bonding operation is simple and efficient.

[0161] In some embodiments of the present application, the substrate layer is made of any one or more combinations of polyvinyl chloride, polyethylene, polypropylene, hexafluoropropylene-vinylidene fluoride copolymer, tetrafluoropropylene-vinylidene fluoride copolymer, trifluorochloropropylene-vinylidene fluoride copolymer, polyethylene terephthalate, polyimide, polyetherimide, polycarbonate, polystyrene, polyphenylene sulfide, polyvinylidene fluoride, polyvinylidene fluoride copolymer, polyarylate, fiber, nylon, and non-woven fabric.

[0162] The above materials are easy to obtain and have good toughness and strength, and can effectively reduce the probability of cracking of the pole piece or shedding of the active material.

[0163] In some embodiments of the present application, the adhesive layer adopts acrylic resin, acrylic acid-acrylate copolymer, butadiene-styrene copolymer, styrene-acrylic acid copolymer, styrene-acrylate copolymer, ethylene-vinyl acetate copolymer, acrylic acid grafted polyethylene, maleic anhydride grafted polyethylene, acrylic acid grafted polypropylene, maleic anhydride grafted polypropylene, polyvinylidene fluoride, carboxymethyl cellulose, polyimide, polyetherimide, polyethylene terephthalate, styrene-isoprene-styrene copolymer rubber, ethylene-vinyl acetate copolymer bisphenol A type epoxy resin, ethylene-vinyl acetate copolymer bisphenol F type epoxy resin, glycerol ether type epoxy resin, glycerol ester type epoxy resin, silicone type resin, polyurethane, styrene-isoprene-styrene copolymer and any one or more combinations thereof.

[0164] The above materials are easy to obtain and have good adhesion, and can firmly adhere the base material layer to the inner surface of the recessed portion 213 .

[0165] For example, Figure 5 As shown, the blocking member 23 includes two first blocking layers 231 and a second blocking layer 232 connected between the two first blocking layers 231. The blocking member 23 is formed as a whole, that is, the second blocking layer 232 is also attached by bonding. The composition structure of the second blocking layer 232 is the same as the composition structure of the first blocking layer 231, which will not be repeated here.

[0166] In some embodiments of the present application, Figure 5 As shown, the dimension L of the first barrier layer 231 along the winding direction C is in the range of 5um to 10um.

[0167] For example, the size L of the first barrier layer 231 along the winding direction C may be 5um, 5.1um, 5.2um, 5.3um, 5.4um, 5.5um, 5.6um, 5.7um, 5.8um, 5.9um, 6um, 6.1um, 6.2um, 6.3um, 6.4um, 6.5um, 6.6um, 6.7um, 6.8um, 6.9um, 7um, 7.1um, 7.2um, 7. 3um, 7.4um, 7.5um, 7.6um, 7.7um, 7.8um, 7.9um, 8um, 8.1um, 8.2um, 8.3um, 8.4um, 8.5um, 8.6um, 8.7um, 8.8um, 8.9um, 9um, 9.1um, 9.2um, 9.3um, 9.4um, 9.5um, 9.6um, 9.7um, 9.8um, 9.9um, 10um.

[0168] In this way, by limiting the size of the first barrier layer 231 along the winding direction C within the range of 5um~10um, the size of the portion covered by the first barrier layer 231 is appropriate, so that the portion prone to powder loss is covered, reducing the probability of powder loss at the cut end, and the capacity of the battery cell 20 will not be affected due to the large covered area.

[0169] In some embodiments of the present application, Figure 5 As shown, the thickness T1 of the first barrier layer 231 is between 10 μm and 20 μm.

[0170] like Figure 5 As shown, the thickness T1 of the first barrier layer 231 can be 10μm, 10.5μm, 11μm, 11.5μm, 12μm, 12.5μm, 13μm, 13.5μm, 14μm, 14.5μm, 15μm, 15.5μm, 16μm, 16.5μm, 17μm, 17.5μm, 18μm, 18.5μm, 19μm, 19.5μm, or 20μm.

[0171] In this way, by limiting the thickness of the first barrier layer 231 within the range of 10μm~20μm, the thickness of the first barrier layer 231 is appropriate and can be attached to the recessed portion 213 without protruding. Moreover, the toughness and strength of the first barrier layer 231 within this thickness range are relatively high, which can effectively reduce the probability of cracking of the pole piece or shedding of the active material.

[0172] In some embodiments of the present application, Figure 6 As shown, the dimension T2 of the recessed portion 213 along the thickness direction of the cathode electrode piece 21 is in the range of 10 μm to 20 μm.

[0173] Exemplarily, the dimension T2 of the recess 213 along the thickness direction of the cathode electrode 21 can be 10μm, 10.5μm, 11μm, 11.5μm, 12μm, 12.5μm, 13μm, 13.5μm, 14μm, 14.5μm, 15μm, 15.5μm, 16μm, 16.5μm, 17μm, 17.5μm, 18μm, 18.5μm, 19μm, 19.5μm, or 20μm.

[0174] In this way, the depth of the recess 213 is appropriate, the reduction amount of active material in the cathode electrode 21 is appropriate, and the first barrier layer 231 attached to the recess 213 does not protrude from the outer surface of the cathode electrode 21, which is beneficial to reduce the probability of electrode cracking or active material falling off.

[0175] In some embodiments of the present application, Figure 7As shown, along the winding axis X perpendicular to the winding direction C, the size W2 of the first barrier layer 231 is between 10 mm and 24 mm.

[0176] like Figure 7 As shown, along the winding axis X perpendicular to the winding direction C, the size W2 of the first barrier layer 231 can be 10mm, 10.5mm, 11mm, 11.5mm, 12mm, 12.5mm, 13mm, 13.5mm, 14mm, 14.5mm, 15mm, 15.5mm, 16mm, 16.5mm, 17mm, 17.5mm, 18mm, 18.5mm, 19mm, 19.5mm, 20mm, 20.5mm, 21mm, 21.5mm, 22mm, 22.5mm, 23mm, 23.5mm, 24mm.

[0177] In this way, by limiting the size W2 of the first barrier layer 231 along the winding axis X to the range of 10 mm to 24 mm, the size W2 of the first barrier layer 231 is suitable and can cover a sufficiently large area of ​​the cathode active material layer 212, thereby greatly reducing the probability of cracking of the electrode or shedding of the active material.

[0178] For example, Figure 7 As shown, along the winding axis X perpendicular to the winding direction C, the size W1 of the cathode electrode piece 21 is in the range of 6 mm to 21 mm. Along the winding axis X perpendicular to the winding direction C, the size W2 of the first barrier layer 231 is in the range of 10 mm to 24 mm. In this way, it is convenient to make the first barrier layer 231 extend beyond the two edges of the cathode electrode piece 21 along the winding axis X, and the extended size is appropriate, so that the first barrier layer 231 covers the cut end more comprehensively, which can better reduce the probability of lithium deposition.

[0179] A second aspect of the present application provides a battery device, which includes at least one battery cell 20 provided in the first aspect.

[0180] Since the battery device includes the battery cell 20 provided by the first aspect, and the battery cell 20 has a large battery capacity and a low short circuit risk, the battery device has a large battery capacity and a low short circuit risk.

[0181] In some embodiments, the battery device may be a battery pack 100 , which includes a battery case 10 and one or more battery cells 20 , wherein the battery cells 20 are housed in the battery case 10 .

[0182] In some embodiments, the battery device may be an energy storage device, and the energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0183] A third aspect of the present application provides an electrical device, which includes the battery cell 20 provided by the first aspect or the battery device provided by the second aspect for providing electrical energy.

[0184] Since the electrical device includes the battery cell 20 provided in the first aspect or the battery device provided in the second aspect, and both the battery cell 20 and the battery device have large battery capacity and low short circuit risk, the electrical device has large battery capacity and low short circuit risk.

[0185] A fourth aspect of the present application provides a method for manufacturing a battery cell, such as Fig. 9 As shown, the method includes:

[0186] S1, providing a cathode electrode sheet, an anode electrode sheet, a first barrier layer and a second barrier layer,

[0187] The cathode electrode sheet 21 includes a cathode current collector 211 and a cathode active material layer 212. The cathode active material layer 212 is disposed on two opposite surfaces of the cathode current collector 211 along the thickness direction of the cathode current collector 211.

[0188] S2, attaching a first barrier layer and a second barrier layer to the feeding end of the cathode electrode piece;

[0189] S3, winding the cathode electrode sheet and the anode electrode sheet along a winding direction;

[0190] S4, cutting the cathode electrode sheet, and attaching a first barrier layer and a second barrier layer to the rolled end of the cathode electrode sheet to form an electrode assembly;

[0191] S5, providing a housing, and installing the electrode assembly into a receiving cavity of the housing to form a battery cell.

[0192] Among them, along the winding direction C, at least one of the two cathode active material layers 212 at the same end of the cathode electrode 21 is provided with a first blocking layer 231, and the surface of the cathode active material layer 212 facing away from the cathode current collector 211 is recessed inward to form a recessed portion 213, and the first blocking layer 231 is attached to the recessed portion 213, and along the winding direction C, the end face of the cathode active material layer 212 is attached with a second blocking layer 232.

[0193] In the battery cell 20 manufactured by the battery cell manufacturing method provided by the embodiment of the present application, the first barrier layer 231 is attached to the recessed portion 213 of the cathode active material layer 212, so that the height of the first barrier layer 231 protruding from the surface of the cathode active material layer 212 can be reduced or the first barrier layer 231 does not protrude, thereby reducing the probability of cracking and powder falling of the pole piece due to the high protrusion of the first barrier layer 231, thereby improving the capacity of the battery cell 20. Moreover, due to the setting of the recessed portion 213, the cathode active material covered by the first barrier layer 231 is correspondingly reduced, so that the amount of lithium ion escape can be reduced, thereby helping to reduce the probability of lithium precipitation, and calmly reducing the probability of short circuit of the battery cell 20, and the end face of the cathode active material layer 212 is covered with the second barrier layer 232, which can prevent the active material on the end face covered by it from falling, thereby further reducing the probability of powder falling at the cut end.

[0194] Specific examples of some embodiments of the present application are described below with reference to the accompanying drawings.

[0195] As a specific example, the battery cell 20 includes a shell 1 and an electrode assembly 2, the shell 1 has a accommodating cavity; the electrode assembly 2 is arranged in the accommodating cavity, the electrode assembly 2 is formed by winding a stack including a cathode electrode sheet 21 and an anode electrode sheet 22 along a winding direction C, the cathode electrode sheet 21 includes a cathode current collector 211 and a cathode active material layer 212 provided on two surfaces opposite to each other along the thickness direction of the cathode current collector 211, the surfaces of the cathode active material layer 212 facing away from the cathode current collector 211 at both ends along the winding direction C are recessed inward to form a recessed portion 213, the recessed portion 213 extends along the winding direction C to an edge of one end of the cathode active material layer 212 close to the recessed portion 213, and the recessed portion 213 extends along the winding axis X to the two edges of the cathode active material layer 212 respectively, and the end of the cathode electrode sheet 21 wound into the innermost circle of the electrode assembly 2 is the entry The feeding end and the end located at the outermost circle are the winding end, and a blocking member 23 is attached to each of the winding end and the winding end. Part of the blocking member 23 (a first blocking layer 231) is pasted on a recessed portion 213 of the feeding end or the winding end, and the other part (the second blocking layer 232) bypasses and is pasted on the end face of the end, and the remaining part (another first blocking layer 231) is pasted on another recessed portion 213 of the end. The blocking member 23 does not protrude from the outer surface of the cathode electrode 21, so that the cathode electrode 21 will not generate local stress due to the protrusion of the blocking member 23, reducing the probability of cracking and powder falling of the raised edge due to local stress extrusion. In addition, due to the setting of the recessed portion 213, the cathode active material of the cathode active material layer 212 is reduced, and the amount of lithium ions released is reduced, which is beneficial to reduce the probability of lithium precipitation and the probability of short circuit of the battery cell 20.

[0196] The portions of the blocking member 23 that are attached to the two opposite recessed portions 213 at the same end (the first blocking layer 231) extend beyond the edges of the recessed portions 213 along the winding axis X, and the extending portions are bonded to each other, thereby reducing the adhesion between the extending portions of the blocking member 23 and the insulating member 24 or the anode electrode sheet 22, which would interfere with the winding process.

[0197] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application is described in detail with reference to the above embodiments, a person skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way.

Claims

1. A battery cell, characterized in that: include: A housing having a receiving cavity; The electrode assembly is arranged in the accommodating cavity, wherein the electrode assembly is formed by winding a laminate including a cathode electrode sheet and an anode electrode sheet along a winding direction, wherein the cathode electrode sheet includes a cathode current collector and a cathode active material layer, and along the thickness direction of the cathode current collector, the cathode active material layer is arranged on two opposite surfaces of the cathode current collector, Along the winding direction, at least one end of the cathode electrode sheet is provided with a first barrier layer, and at least one of the two cathode active material layers at the same end of the cathode electrode sheet is provided with the first barrier layer. The surface of the cathode active material layer facing away from the cathode current collector is inwardly recessed to form a recessed portion, and the first barrier layer is attached to the recessed portion; A second barrier layer is attached to an end surface of at least one end of the cathode active material layer along the winding direction.

2. The battery cell according to claim 1, characterized in that: The second barrier layer is also attached to an end surface of the cathode current collector along the winding direction.

3. The battery cell according to claim 1, characterized in that: The recessed portion extends along the winding direction to an edge of the cathode active material layer close to the recessed portion. The first barrier layer and the second barrier layer located at the same end of the cathode electrode piece are connected.

4. The battery cell according to claim 1, characterized in that: The two cathode active material layers at the same end of the cathode electrode sheet along the winding direction both have the recessed portion.

5. The battery cell according to claim 4, characterized in that: The two recessed portions located at the same end of the cathode electrode are respectively a first recessed portion and a second recessed portion, the first barrier layer attached to the first recessed portion and the first barrier layer attached to the second recessed portion are connected through a second barrier layer, and the second barrier layer is attached to the end face of one end of the cathode electrode close to the first recessed portion and the second recessed portion along the winding direction.

6. The battery cell according to claim 4 or 5, characterized in that: Along a winding axis direction perpendicular to the winding direction, the recessed portions extend to two edges of the cathode active material layer respectively.

7. The battery cell according to claim 6, characterized in that: The two recessed portions located at the same end of the cathode electrode sheet are respectively a first recessed portion and a second recessed portion, the first barrier layer attached to the first recessed portion has two ends along the winding axis that extend beyond two edges of the first recessed portion, the first barrier layer attached to the second recessed portion has two ends along the winding axis that extend beyond two edges of the second recessed portion, and the portion of the first barrier layer attached to the first recessed portion that extends beyond the edge of the first recessed portion is connected to the portion of the first barrier layer attached to the second recessed portion that extends beyond the edge of the second recessed portion.

8. The battery cell according to claim 4, characterized in that: A third barrier layer is provided at at least one end of the cathode electrode sheet along the winding direction, and the third barrier layer is attached to at least one of the two opposite end surfaces of the cathode electrode sheet along a winding axis perpendicular to the winding direction.

9. The battery cell according to claim 8, characterized in that: The two recessed portions located at the same end of the cathode electrode piece are respectively a first recessed portion and a second recessed portion, and the first barrier layer attached to the first recessed portion and the first barrier layer attached to the second recessed portion are connected through the third barrier layer.

10. The battery cell according to any one of claims 1 to 5, characterized in that: Along the thickness direction of the cathode electrode sheet, the depth of the recessed portion is not less than the thickness of the first barrier layer.

11. The battery cell according to claim 1, characterized in that: The first barrier layer includes a substrate layer and an adhesive layer attached to a surface of the substrate layer, and the substrate layer is bonded to the cathode plate through the adhesive layer.

12. The battery cell according to claim 1, characterized in that: The second barrier layer includes a substrate layer and an adhesive layer attached to a surface of the substrate layer, and the substrate layer is bonded to the cathode plate through the adhesive layer.

13. The battery cell according to claim 8, characterized in that: The third barrier layer includes a substrate layer and an adhesive layer attached to a surface of the substrate layer, and the substrate layer is bonded to the cathode plate through the adhesive layer.

14. The battery cell according to any one of claims 11 to 13, characterized in that: The substrate layer is made of at least one of polyvinyl chloride, polyethylene, polypropylene, hexafluoropropylene-vinylidene fluoride copolymer, tetrafluoropropylene-vinylidene fluoride copolymer, trifluorochloropropylene-vinylidene fluoride copolymer, polyethylene terephthalate, polyimide, polyetherimide, polycarbonate, polystyrene, polyphenylene sulfide, polyvinylidene fluoride, polyarylate, fiber, nylon, and non-woven fabric.

15. The battery cell according to any one of claims 11 to 13, characterized in that: The adhesive layer is made of at least one of acrylic resin, acrylic acid-acrylate copolymer, butadiene-styrene copolymer, styrene-acrylic acid copolymer, styrene-acrylate copolymer, ethylene-vinyl acetate copolymer, acrylic acid grafted polyethylene, maleic anhydride grafted polyethylene, acrylic acid grafted polypropylene, maleic anhydride grafted polypropylene, polyvinylidene fluoride, carboxymethyl cellulose, polyimide, polyetherimide, polyethylene terephthalate, ethylene-vinyl acetate copolymer bisphenol A type epoxy resin, ethylene-vinyl acetate copolymer bisphenol F type epoxy resin, glycerol ether type epoxy resin, glycerol ester type epoxy resin, silicone type resin, polyurethane, and styrene-isoprene-styrene copolymer.

16. The battery cell according to any one of claims 1 to 5, characterized in that: The size of the first barrier layer along the winding direction is in the range of 5um to 10um.

17. The battery cell according to any one of claims 1 to 5, characterized in that: The thickness of the first barrier layer is between 10 μm and 20 μm.

18. The battery cell according to any one of claims 1 to 5, characterized in that: Along the winding axis direction perpendicular to the winding direction, the size of the first barrier layer is between 10 mm and 24 mm.

19. A battery device, characterized in that: include: At least one battery cell according to any one of claims 1 to 18.

20. An electrical device, characterized in that: The electrical device comprises the battery cell according to any one of claims 1 to 18 or the battery device according to claim 19 for providing electrical energy.

21. A method for manufacturing a battery cell, characterized in that: include: Providing a cathode electrode sheet, an anode electrode sheet, a first barrier layer and a second barrier layer, The cathode electrode sheet comprises a cathode current collector and a cathode active material layer, and along the thickness direction of the cathode current collector, the cathode active material layer is arranged on two opposite surfaces of the cathode current collector; Attaching the first barrier layer and the second barrier layer to the feeding end of the cathode electrode sheet; Winding the cathode electrode sheet and the anode electrode sheet along a winding direction; Cutting the cathode electrode sheet, and attaching the first barrier layer and the second barrier layer to the rolled end of the cathode electrode sheet to form an electrode assembly; Providing a housing, and placing the electrode assembly into a receiving cavity of the housing to form a battery cell; Among them, along the winding direction, at least one of the two cathode active material layers at the same end of the cathode electrode sheet is provided with the first barrier layer, the surface of the cathode active material layer facing away from the cathode current collector is recessed inward to form a recessed portion, and the first barrier layer is attached to the recessed portion, and along the winding direction, the second barrier layer is attached to the end face of the cathode active material layer.

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