CN118645710A

CN118645710A - Battery cell, battery device, electricity consumption device and battery cell manufacturing method

Info

Publication number: CN118645710A
Application number: CN202411106598.2A
Authority: CN
Inventors: 吴凯; 黄滔; 谢岚; 吴小辉; 林真; 李伟
Original assignee: Contemporary Amperex Technology Co Ltd
Current assignee: Contemporary Amperex Technology Co Ltd
Priority date: 2024-08-13
Filing date: 2024-08-13
Publication date: 2024-09-13

Abstract

The application discloses a battery cell, a battery device, an electricity utilization device and a battery cell manufacturing method. A battery cell comprising: a housing having a receiving cavity; the electrode assembly is arranged in the accommodating cavity and is formed by winding a laminated body comprising a cathode pole piece and an anode pole piece along the winding direction, the cathode pole piece comprises a cathode current collector and a cathode active material layer, the cathode active material layer is arranged on two opposite surfaces of the cathode current collector along the thickness direction of the cathode current collector, at least one end of the cathode pole piece is provided with a first barrier layer along the winding direction, at least one of the two cathode active material layers at the same end of the cathode pole piece is provided with a first barrier layer, the surface of the cathode active material layer, facing away from the cathode current collector, is inwards recessed to form a recessed part, the first barrier layer is attached in the recessed part, and a second barrier layer is attached to the end face of at least one end of the cathode active material layer along the winding direction. The application can improve the battery capacity and reduce the short circuit risk.

Description

Battery cell, battery device, electricity consumption device and battery cell manufacturing method

Technical Field

The application relates to the technical field of batteries, in particular to a battery cell, a battery device, an electric device and a battery cell manufacturing method.

Background

New energy batteries are increasingly used in life and industry, for example, new energy automobiles having a battery mounted therein have been widely used, and in addition, batteries are increasingly used in the field of energy storage and the like. In a new energy vehicle that carries a battery, the battery may be used to fully or partially power. In the energy storage field, the battery may be mounted in an energy storage case or directly on the user side.

In the case of a short circuit, the battery may rapidly heat up and may even cause a fire explosion, and therefore, how to reduce the risk of the short circuit of the battery is one of the problems to be studied in the industry. In addition, how to increase the battery capacity of a battery has been a subject of continuous research in the industry.

Disclosure of Invention

In order to solve the above technical problems, the present application provides a battery cell, a battery device, an electric device and a battery cell manufacturing method with large battery capacity and low short circuit risk.

The application is realized by the following technical scheme.

The first aspect of the present application provides a battery cell, comprising: a housing having a receiving cavity; the electrode assembly is arranged in the accommodating cavity and is formed by winding a laminated body comprising a cathode pole piece and an anode pole piece along a winding direction, the cathode pole piece comprises a cathode current collector and a cathode active material layer, the cathode active material layer is arranged on two opposite surfaces of the cathode current collector along the thickness direction of the cathode current collector, a first blocking layer is arranged at least one end of the cathode pole piece along the winding direction, the first blocking layer is arranged at least one of the two cathode active material layers at the same end of the cathode pole piece, the surface of the cathode active material layer, which is opposite to the cathode current collector, is inwards recessed to form a recessed part, and the first blocking layer is attached in the recessed part; a second barrier layer is attached to an end face of at least one end of the cathode active material layer in the winding direction.

In the battery monomer provided by the embodiment of the application, the first barrier layer is attached to the concave part of the cathode active material layer, so that the height of the first barrier layer protruding out of the surface of the cathode active material layer can be reduced or the first barrier layer does not protrude, the probability of occurrence of cracking and powder dropping of the pole piece due to higher protrusion of the first barrier layer can be reduced, and the capacitance of the battery monomer is improved. Moreover, due to the arrangement of the concave part, the cathode active material at the covering part of the first barrier layer is correspondingly reduced, so that the amount of lithium ions released can be reduced, thereby being beneficial to reducing the occurrence probability of lithium precipitation and reducing the occurrence probability of short circuit of the battery monomer from the container. And the end face of the cathode active material layer is covered with a second blocking layer, so that the active material of the end face covered by the second blocking layer can be blocked from falling off, and the occurrence probability of powder falling off at the cut end is reduced to a greater extent.

In some embodiments, the second barrier layer is further attached to an end face of the cathode current collector in the winding direction.

Therefore, the second blocking layer can block powder falling on the end face of the cathode active material layer and can block metal scraps on the end face of the cathode current collector, so that the probability that the metal scraps pierce the separator is reduced, and the probability of short circuit is reduced.

In some embodiments, the recess extends to an edge of one end of the cathode active material layer near the recess in the winding direction, and the first barrier layer and the second barrier layer at the same end of the cathode sheet are connected.

The concave part extends to the end edge of the cathode active material layer, which is close to the concave part, along the winding direction, so that the concave part is closer to the end face of the cathode active material layer, the first blocking layer is closer to the end face of the cathode active material layer, and the first blocking layer is connected with the second blocking layer to more comprehensively block the surface of the cutting end, thereby reducing the probability of powder falling of the cutting end to a greater extent.

In some embodiments, both of the cathode active material layers at the same end of the cathode sheet in the winding direction have the recess.

Therefore, the first barrier layers are attached to the two sides of the same end, and the occurrence rate of powder falling of the cutting end is further reduced.

In some embodiments, the two recesses at the same end of the cathode sheet are a first recess and a second recess, respectively, the first barrier layer attached to the first recess and the first barrier layer attached to the second recess are connected by a second barrier layer attached to an end face of the cathode sheet near one end of the first recess and the second recess in the winding direction.

Therefore, the tightness of the two connected first blocking layers and the second blocking layers for covering the cut-off ends of the cathode pole pieces is high, the surfaces of the cut-off ends are more comprehensively blocked, and therefore the occurrence probability of powder falling at the cut-off ends is reduced to a greater extent.

In some embodiments, the depressions extend to both edges of the cathode active material layer, respectively, in a winding axis direction perpendicular to the winding direction.

Therefore, the area of the concave part is larger, the cathode active material at the cutting end is reduced more, and the amount of lithium ions released is reduced more, so that the probability of occurrence of lithium precipitation is reduced, and the probability of occurrence of short circuit of the battery monomer is reduced from the container. Moreover, the area of the concave part is larger, so that the coverage area of the first blocking layer is larger, and metal scraps and powder falling at the cut-off end of the cathode current collector are further blocked.

In some embodiments, the two concave portions located at the same end of the cathode sheet are a first concave portion and a second concave portion, two ends of the first blocking layer attached to the first concave portion along the winding axis respectively exceed two edges of the first concave portion, two ends of the first blocking layer attached to the second concave portion along the winding axis respectively exceed two edges of the second concave portion, and a portion of the first blocking layer attached to the first concave portion exceeding an edge of the first concave portion and a portion of the first blocking layer attached to the second concave portion exceeding an edge of the second concave portion are connected with each other.

So, the area of the cathode active material layer that first barrier covered is bigger, and first barrier is more comprehensive to cutting off end cover, and the probability that the lithium phenomenon takes place is reduced in the play that can be better, moreover, the part interconnect that exceeds has improved the firm nature that first barrier and cathode pole piece attached, improves and blocks the effect of falling metal piece, falling powder.

In some embodiments, at least one end of the cathode sheet in the winding direction is provided with a third barrier layer to which at least one of opposite end faces of the cathode sheet is attached in a winding axis direction perpendicular to the winding direction.

Therefore, the end face of the cathode pole piece along the winding axial direction is covered with the third blocking layer, active substances and metal fragments of the end face covered by the third blocking layer can be blocked from falling, and therefore the probability of powder and metal fragments falling at the cutting end is reduced to a greater extent.

In some embodiments, the two recesses at the same end of the cathode sheet are a first recess and a second recess, respectively, and the first barrier layer attached to the first recess and the first barrier layer attached to the second recess are connected by the third barrier layer.

Therefore, the tightness of the two connected first blocking layers and the third blocking layer for covering the cut-off end of the cathode pole piece is high, the surface of the cut-off end is more comprehensively blocked, and therefore the occurrence probability of powder falling at the cut-off end is reduced to a greater extent.

In some embodiments, the depth value of the recess is not less than the thickness value of the first barrier layer along the thickness direction of the cathode sheet.

Therefore, the first barrier layer is not protruded out of the outer surface of the cathode pole piece, the occurrence probability of cracking and powder falling at the positions of the cathode pole piece and the anode pole piece corresponding to the protruded positions is reduced to a greater extent, and the capacitance of the battery cell is further improved.

In some embodiments, the first barrier layer includes a substrate layer and a glue layer attached to a surface of the substrate layer, the substrate layer being adhered to the cathode pole piece by the glue layer.

Thus, the first barrier layer is attached to the concave portion of the cathode active material layer by means of bonding, the bonding operation is simple, and the operation efficiency is high.

In some embodiments, the second barrier layer includes a substrate layer and a glue layer attached to a surface of the substrate layer, the substrate layer being adhered to the cathode pole piece by the glue layer.

Therefore, the second barrier layer is attached to the end face of the cathode pole piece along the winding direction in an adhesive mode, the adhesive operation is simple, and the operation efficiency is high.

In some embodiments, the third barrier layer includes a substrate layer and a glue layer attached to a surface of the substrate layer, the substrate layer being adhered to the cathode pole piece by the glue layer.

In this way, the third barrier layer is attached to the end face of the cut end of the cathode pole piece along the winding axial direction in an adhesive manner, the adhesive operation is simple, and the operation efficiency is high.

In some embodiments, the substrate layer is at least one of polyvinyl chloride, polyethylene, polypropylene, hexafluoropropylene-vinylidene fluoride copolymer, tetrafluoropropene-vinylidene fluoride copolymer, trifluorochloropropene-vinylidene fluoride copolymer, polyethylene terephthalate, polyimide, polyetherimide, polycarbonate, polystyrene, polyphenylene sulfide, polyvinylidene fluoride copolymer, polyarylate, fiber, nylon, nonwoven fabric.

The material is easy to obtain, has good toughness and strength, and can well reduce the occurrence probability of cracking of the pole piece or falling of active substances.

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

The material is easy to obtain, has good viscosity and can firmly adhere the substrate layer to the inner surface of the concave part.

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

Therefore, the size of the first barrier layer along the winding direction is limited in the range of 5 um-10 um, so that the size of the part covered by the first barrier layer is proper, the part easy to fall off powder is covered, the probability of falling powder at the cutting end is reduced, and the electric capacity of the battery monomer cannot be influenced due to the too large covered area.

In some embodiments, the first barrier layer has a thickness of 10 μm to 20 μm.

Therefore, the thickness of the first barrier layer is limited within the range of 10-20 mu m, so that the first barrier layer is suitable in thickness and can be attached in the concave part without protruding, and the first barrier layer within the thickness range is high in toughness and strength, so that the occurrence probability of cracking of a pole piece or falling of an active substance can be well reduced.

In some embodiments, the first barrier layer has a dimension of 10mm to 24mm along a winding axis perpendicular to the winding direction.

Therefore, the size of the first barrier layer along the winding axial direction is limited within the range of 10 mm-24 mm, so that the size of the first barrier layer is suitable, and a cathode active material layer with a large enough area can be covered, and the occurrence probability of pole piece cracking or active material falling is well reduced.

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

Since the battery device comprises the battery cell provided in 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.

A third aspect of the application provides an electrical device comprising a battery cell provided in the first aspect or a battery device provided in the second aspect for providing electrical energy.

The power utilization device comprises the battery cell provided in the first aspect or the battery device provided in the second aspect, and the battery cell and the battery device both have large battery capacity and low short circuit risk, so the power utilization device has large battery capacity and low short circuit risk.

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

Providing a cathode pole piece, an anode pole piece, a first barrier layer and a second barrier layer,

The cathode plate comprises a cathode current collector and a cathode active material layer, and the cathode active material layer is arranged on two opposite surfaces of the cathode current collector along the thickness direction of the cathode current collector;

attaching the first barrier layer and the second barrier layer to the feed end of the cathode plate;

Winding the cathode pole piece and the anode pole piece along a winding direction;

Cutting off the cathode pole piece, and attaching the first barrier layer and the second barrier layer at the winding end of the cathode pole piece to form an electrode assembly;

providing a housing, and loading the electrode assembly into a containing cavity of the housing to form a battery cell;

At least one of the two cathode active material layers at the same end of the cathode pole piece is provided with the first barrier layer along the winding direction, the surface of the cathode active material layer, which is opposite to the cathode current collector, is inwards recessed to form a recessed part, the first barrier layer is attached in the recessed part, and the second barrier layer is attached to the end face of the cathode active material layer along the winding direction.

In the battery cell manufactured by the manufacturing method of the battery cell provided by the embodiment of the application, the first barrier layer is attached to the concave part of the cathode active material layer, so that the height of the first barrier layer protruding out of the surface of the cathode active material layer can be reduced or the first barrier layer does not protrude, the probability of occurrence of pole piece cracking and powder falling caused by higher protrusion of the first barrier layer can be reduced, and the electric capacity of the battery cell is improved. Moreover, due to the arrangement of the concave part, the cathode active material at the covering part of the first barrier layer is correspondingly reduced, so that the amount of lithium ions released can be reduced, thereby being beneficial to reducing the occurrence probability of lithium precipitation and reducing the occurrence probability of short circuit of the battery monomer from the container. And the end face of the cathode active material layer is covered with a second blocking layer, so that the active material of the end face covered by the second blocking layer can be blocked from falling off, and the occurrence probability of powder falling off at the cut end is reduced to a greater extent.

The beneficial effects of the embodiment of the disclosure include: the application provides a battery cell, a battery device, an electric device and a battery cell manufacturing method, wherein the battery cell has large battery capacity and low short circuit risk.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the application. Also, like reference numerals are used to designate like parts throughout the accompanying drawings. In the drawings:

FIG. 1 is a schematic structural view of a vehicle according to one or more embodiments;

Fig. 2 is a schematic structural view of a battery pack according to one or more embodiments;

fig. 3 is a schematic structural view of a battery cell according to one or more embodiments;

Fig. 4 is a schematic structural view of an electrode assembly according to one or more embodiments;

FIG. 5 is an enlarged view of FIG. 4 at A;

FIG. 6 is a schematic view of a portion of a structure of a negative electrode tab according to one or more embodiments;

FIG. 7 is a top view of one construction of the portion shown in FIG. 5;

FIG. 8 is a top view of another configuration of the portion shown in FIG. 5;

fig. 9 is a flow diagram of a method of manufacturing a battery cell according to one or more embodiments.

Description of the reference numerals

1000. A vehicle; 100. a battery pack; 10. a battery box; 101. a case cover; 102. a case; 200. a controller; 300. a motor;

20. A battery cell; 1. a housing; 11. an end cap; 12. a housing; 2. an electrode assembly; 21. a cathode pole piece; 211. a cathode current collector; 2111. a second end face; 212. a cathode active material layer; 2121. a first end face; 213. a recessed portion; 213a first recess; 213b second recess; 22. an anode pole piece; 23. a blocking member; 231. a first barrier layer; 232. a second barrier layer; 233. a third barrier layer; 24. a spacer; 25. a tab; 3. a pressure release mechanism; 4. a pole.

Detailed Description

Embodiments of the technical scheme of the present application will be described in detail below with reference to the accompanying drawings. The following examples are only for more clearly illustrating the technical aspects of the present application, and thus are merely examples, and are not intended to limit the scope of the present application.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having" and any variations thereof in the description of the application and in the description of the drawings above are intended to cover non-exclusive inclusions.

In the description of embodiments of the present application, the technical terms "first," "second," "third," etc. are used merely to distinguish between different objects and should not be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated, a particular order or a primary or secondary relationship. In the description of the embodiments of the present application, the meaning of "plurality" is two or more unless explicitly defined otherwise.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.

In the description of the embodiments of the present application, the term "and/or" is merely an association relationship describing an association object, and indicates that three relationships may exist, for example, a and/or B may indicate: a exists alone, A and B exist together, and B exists alone. In this context, the character "/" generally indicates that the associated object is an "or" relationship.

In the description of the embodiments of the present application, the orientation or positional relationship indicated by the technical terms "length", "width", "thickness", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "circumferential", etc. are orientation or positional relationship based on the drawings, and are merely for convenience of describing the embodiments of the present application and for simplifying the description, and are not intended to indicate or imply that the apparatus or element in question must have a specific orientation, be constructed, operated, or used in a specific orientation, and thus should not be construed as limiting the embodiments of the present application.

In the description of the embodiments of the present application, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured" and the like should be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally formed; or may be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the embodiments of the present application will be understood by those of ordinary skill in the art according to specific circumstances.

In the description of the embodiments of the present application, unless explicitly specified and limited otherwise, the term "contact" is to be understood in a broad sense as either direct contact or contact across an intermediate layer, as either contact with substantially no interaction force between the two in contact or contact with interaction force between the two in contact.

The present application will be described in detail below.

At present, new energy batteries are increasingly widely applied to life and industry. The new energy battery is not only applied to energy storage power supply systems such as hydraulic power, firepower, wind power and solar power stations, but also widely applied to electric vehicles such as electric bicycles, electric motorcycles, electric automobiles, and a plurality of fields such as aerospace. With the continuous expansion of the application field of the power battery, the market demand of the power battery is also continuously expanding.

The battery cell includes an electrode assembly including a cathode electrode tab, an anode electrode tab, and a separator, and an electrolyte. The battery cell mainly relies on metal ions to move between the cathode and anode electrode sheets. The cathode plate comprises 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 comprises a cathode current collecting part and a cathode convex part protruding out of the cathode current collecting part, the cathode current collecting part is coated with a cathode active material layer, at least part of the cathode convex part is not coated with the cathode active material layer, and the cathode convex part is used as a cathode tab. Taking a lithium ion battery as an example, the material of the cathode current collector may be aluminum, the cathode active material layer includes a cathode active material, and the cathode active material may be lithium cobaltate, lithium iron phosphate, ternary lithium, lithium manganate, or the like. The anode plate comprises 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 comprises an anode current collecting part and an anode convex part protruding out of the anode current collecting part, the anode current collecting part is coated with an anode active material layer, at least part of the anode convex part is not coated with the anode active material layer, and the anode convex part is used as an anode lug. The material of the anode current collector may be copper, the anode active material layer includes an anode active material, and the anode active material may be carbon or silicon, etc. In order to ensure that the high current is passed without fusing, the number of cathode lugs is multiple and stacked together, and the number of anode lugs is multiple and stacked together. In addition, the electrode assembly may be a roll-to-roll structure, and embodiments of the present application are not limited thereto.

When the lithium ion battery monomer is charged, lithium ions are extracted from the cathode active material layer and are intercalated into the anode active material layer, but abnormal conditions may occur, for example, too many lithium ions are extracted from the cathode active material layer, and the lithium intercalation space of the anode active material layer is insufficient, the resistance of the lithium ions to intercalate into the anode active material layer is too large or the lithium ions are extracted from the cathode active material layer too fast, the extracted lithium ions cannot be intercalated into the anode active material layer of the anode pole piece in an equivalent amount, and the lithium ions which cannot be intercalated into the anode pole piece can only obtain electrons on the surface of the anode pole piece, so that a metal lithium simple substance is formed, namely a lithium precipitation phenomenon. The lithium is separated, so that the performance of the lithium ion battery monomer is reduced, the cycle life is greatly shortened, the quick charge capacity of the lithium ion battery monomer is limited, when the lithium separation is serious, lithium crystals can be formed on the surface of the anode plate by separated lithium ions, and the lithium crystals easily puncture the separator, so that the risk of short circuit between the adjacent cathode plate and the anode plate is caused.

In the battery pack, the problem that the powder is easily fallen in the cutting end department at the both ends along the winding direction of cathode pole piece and positive pole piece, in order to reduce the probability that the powder is fallen in the fracture emergence, among the prior art, paste the barrier layer to the hidden danger positions such as easy powder falling, aluminium leakage of the cutting end of cathode pole piece, reduce the probability of falling powder, aluminium leakage through the physical separation, but paste the barrier layer and brought following several problems: firstly, the adhered barrier layer protrudes out of the cathode active material layer by a certain height, so that after the position is subjected to a hot pressing process or ageing, the problems of pole piece cracking, powder falling and the like are generated at the positions of the cathode pole piece and the anode pole piece corresponding to the protruding edge of the barrier layer due to local stress extrusion, and the capacity of the battery is affected. Secondly, the blocking layer covers a part of the cathode active layer, and can prevent the cathode at the covered position from delithiation in theory, however, in fact, the blocking layer cannot realize complete electrochemical blocking, cannot completely prevent the lithium ions of the cathode active particles at the covered position from coming out, and the anode at the position corresponding to the blocking layer has limited lithium intercalation capacity, so that lithium metal is easily separated out from the surface of the anode plate, namely, the phenomenon of edge lithium separation occurs, and further, the membrane is possibly pierced, and the problem of short circuit of the battery cell is caused.

In order to solve the problems, the application can reduce the protruding height of the blocking layer or not by thinning the part of the cathode active material layer of the cathode electrode plate, which is adhered with the blocking layer, thereby reducing the probability of cracking and powder falling of the electrode plate caused by protruding of the blocking layer and improving the battery capacity. In addition, as the part of the cathode active material layer, which is adhered with the blocking layer, is thinned, the cathode active material covered by the blocking layer is correspondingly reduced, so that the amount of lithium ions extracted can be reduced, thereby being beneficial to reducing the occurrence probability of lithium precipitation and reducing the occurrence probability of short circuit of battery monomers from the container.

Based on such design concept, the inventors of the present application devised a battery cell including a case having a receiving chamber, and an electrode assembly; the electrode assembly is arranged in the accommodating cavity and is formed by winding a laminated body comprising a cathode pole piece and an anode pole piece along the winding direction, the cathode pole piece comprises a cathode current collector and a cathode active material layer, the cathode active material layer is arranged on two opposite surfaces of the cathode current collector along the thickness direction of the cathode current collector, a first barrier layer is arranged at least one end of the cathode pole piece along the winding direction, at least one of the two cathode active material layers at the same end of the cathode pole piece is provided with a first barrier layer, the surface of the cathode active material layer, facing away from the cathode current collector, is inwards recessed to form a recessed part, and the first barrier layer is attached in the recessed part.

The first barrier layer is attached to the concave portion of the cathode active material layer, and thus, the protruding height of the first barrier layer or the first barrier layer is not protruding, so that the occurrence of cracking and powder falling of the pole piece due to the protruding of the first barrier layer can be reduced, and the battery capacity can be improved. Moreover, due to the arrangement of the concave part, the cathode active material covered by the first barrier layer is correspondingly reduced, so that the amount of lithium ions released can be reduced, thereby being beneficial to reducing the occurrence probability of lithium precipitation and reducing the occurrence probability of short circuit of the battery monomer from the container.

The battery cell provided by the embodiment of the application can be assembled into a battery cell assembly in groups for providing voltage and capacity. The plurality of battery cells of the battery cell assembly (Battery Cell Assembly) may be connected in series, parallel, or series-parallel by a bus bar member.

The battery cell provided by the embodiment of the application can be applied to a battery device, and the battery device (Battery Apparatus) can comprise one or more battery cell assemblies for providing voltage and capacity. The battery cell assembly (Battery Cell Assembly) may include a plurality of battery cells connected in series, parallel, or series-parallel by a bus bar.

In some embodiments, the battery cell assembly (Battery Cell Assembly) is generally formed from an arrangement of a plurality of battery cells; as an example, the Battery cell assembly may be a Battery Module (Battery Module) formed by arranging and fixing a plurality of Battery cells to form an independent Module. As an example, the battery module may be formed by binding a plurality of battery cells by a tie.

In some embodiments, the battery device may be a battery Pack (battery Pack) that includes a battery compartment and one or more battery cell assemblies that are housed in the battery compartment.

As an example, the battery cell assembly may be a battery module, and the battery cell assembly may be received in the battery case in such a manner that the battery module is fixed in the battery case.

As an example, the battery cell assembly may be accommodated in the battery case by directly fixing a plurality of battery cells to the battery case.

In some embodiments, the battery device refers to an energy storage device comprising a battery compartment with a door on at least one side of the battery compartment. The energy storage device comprises an energy storage container, an energy storage electric cabinet and the like.

The technical scheme described in the embodiment of the application is applicable to various electric devices using battery monomers and battery devices, such as mobile phones, portable equipment, notebook computers, battery cars, electric toys, electric tools, vehicles, ships, spacecraft and the like, and for example, the spacecraft comprises planes, rockets, spaceships, spacecraft and the like.

In the following embodiments, for convenience of explanation, the electric device according to an embodiment of the present application will be described by taking the vehicle 1000 as an example. The following description refers to the accompanying drawings.

FIG. 1 is a schematic structural view of a vehicle according to one or more embodiments.

The vehicle 1000 may be a fuel oil vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or a range-extended vehicle. As shown in fig. 1, the battery pack 100 is provided inside the vehicle 1000, and the battery pack 100 may be provided at the bottom or the head or the tail of the vehicle 1000. The battery pack 100 may be used for power supply of the vehicle 1000, for example, the battery pack 100 may serve as an operating power source of the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300, the controller 200 being configured to control the battery pack 100 to power the motor 300, for example, for operating power requirements during start-up, navigation, and travel of the vehicle 1000.

In some embodiments of the present application, the battery pack 100 may not only serve as an operating power source for the vehicle 1000, but also as a driving power source for the vehicle 1000, instead of or in part instead of fuel oil or natural gas, to provide driving power for the vehicle 1000.

Fig. 2 is a schematic structural view of a battery pack 100 according to one or more embodiments.

As shown in fig. 2, the battery pack 100 includes a battery case 10 and at least one battery cell 20, wherein an accommodating space is provided in the battery case 10, and the at least one battery cell 20 is accommodated in the accommodating space.

In some embodiments of the present application, the battery case 10 includes a case 102 and a case cover 101, the case cover 101 covering over the case 102, thereby forming the receiving space between the case 102 and the case cover 101.

The case body 102 may have a hollow structure with an opening at one end, the case cover 101 may have a plate-shaped structure, and the case cover 101 covers the opening side of the case body 102, so that the case cover 101 and the case body 102 together define an accommodating space; the case cover 101 and the case 102 may be hollow structures each having one side open, and the open side of the case cover 101 may be closed to the open side of the case 102. Of course, the battery case 10 formed by the case cover 101 and the case body 102 may be of various shapes, such as a cylinder, a rectangular parallelepiped, etc.

In the battery pack 100, the plurality of battery cells 20 may be connected in series, parallel or a series-parallel connection, wherein the series-parallel connection refers to that the plurality of battery cells 20 are connected in series or parallel. The plurality of battery cells 20 can be directly connected in series or in parallel or in series-parallel, and then the whole body formed by the plurality of battery cells 20 is placed in the accommodating space formed by the box body 102 and the box cover 101; of course, the battery pack 100 may also be a battery module formed by connecting a plurality of battery cells 20 in series or parallel or series-parallel connection, and a plurality of battery modules are connected in series or parallel or series-parallel connection to form a whole and are accommodated in an accommodating space formed by the case 102 and the case cover 101. The battery pack 100 may further include other structures, for example, the battery pack 100 may further include a bus bar member for making electrical connection between the plurality of battery cells 20.

In the embodiment of the present application, the battery cell 20 may be a secondary battery, and the secondary battery refers to a battery cell that can be continuously used by activating the active material in a charging manner after the battery cell is discharged.

The battery cell 20 may be a lithium 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 by the embodiment of the application.

The battery cell 20 may be a cylindrical battery cell, a prismatic battery cell, or a battery cell of other shapes, including a square-case battery cell, a blade-shaped battery cell, a polygonal-prismatic battery cell, such as a hexagonal-prismatic battery cell, etc., and the present application is not particularly limited.

Some embodiments of the present application are described in detail below with reference to fig. 3 to 9.

Fig. 3 is a schematic structural view of a battery cell according to one or more embodiments; fig. 4 is a schematic structural view of an electrode assembly according to one or more embodiments; FIG. 5 is an enlarged view of FIG. 4 at A; FIG. 6 is a schematic view of a portion of a structure of a negative electrode tab according to one or more embodiments; FIG. 7 is a top view of one construction of the portion shown in FIG. 5; FIG. 8 is a top view of another configuration of the portion shown in FIG. 5; fig. 9 is a flow diagram of a method of manufacturing a battery cell according to one or more embodiments.

In the description of the embodiment of the present application, for convenience of explanation, the winding direction of the cathode sheet 21 and the anode sheet 22 in the electrode assembly 2 is indicated by the direction of arrow C, and the winding axis direction perpendicular to the winding direction C is indicated by the direction of arrow X.

The first aspect of the present application provides a battery cell 20, as shown in fig. 3 to 7, the battery cell 20 including a case 1 and an electrode assembly 2, the case 1 having a receiving cavity; the electrode assembly 2 is arranged in the accommodating cavity, the electrode assembly 2 is formed by winding a laminated body comprising a cathode pole piece 21 and an anode pole piece 22 along a winding direction C, the cathode pole piece 21 comprises a cathode current collector 211 and a cathode active material layer 212, the cathode active material layer 212 is arranged on two opposite surfaces of the cathode current collector 211 along the thickness direction of the cathode current collector 211, at least one end of the cathode pole piece 21 is provided with a first barrier layer 231 along the winding direction C, at least one of the two cathode active material layers 212 on the same end of the cathode pole piece 21 is provided with the first barrier layer 231, the surface of the cathode active material layer 212, facing away from the cathode current collector 211, is inwards recessed to form a recessed part 213, and the first barrier layer 231 is attached in the recessed part 213.

The case 1 has a shell-like structure for sealing the electrode assembly 2 and the electrolyte. 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), an aluminum-plastic film or the like. The housing 1 may be of various shapes and various sizes, such as rectangular parallelepiped, cylindrical, hexagonal prism, etc. Specifically, the shape of the case 1 may be determined according to the specific shape and size of the electrode assembly 2. The material of the housing 1 may be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which is not particularly limited in the embodiment of the present application. One or more electrode assemblies 2 may be contained in the receiving chamber of the case 1.

In some embodiments, the electrode assembly 2 further includes a separator 24 disposed between the cathode and anode electrode sheets 21 and 22, the separator 24 may function to prevent cathode and anode shorting while allowing the passage of active ions. In some embodiments, the separator is a separator film. The type of the separator is not particularly limited, and any known porous separator having good chemical stability and mechanical stability can be used. As an example, the main material of the separator may be at least one selected from glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. In some embodiments, the separator is a solid state electrolyte. The solid electrolyte is arranged between the anode and the cathode and plays roles in transmitting ions and isolating the anode and the cathode.

In the embodiment of the present application, the winding direction C is the direction in which the cathode pole piece 21 and the anode pole piece 22 are wound circumferentially from inside to outside. In fig. 4, the winding direction C is clockwise. The two ends along the winding direction C can be the two ends of the pole piece in the length direction after the pole piece is unfolded; the direction along the winding direction C can also be the direction intersecting the height direction and the thickness direction of the pole piece when the battery cell is vertically placed.

Only one end of the surface of the cathode active material layer 212 facing away from the cathode current collector 211 along the winding direction C is formed with a recess 213, or both ends of the cathode active material layer 212 along the winding direction C are formed with recesses 213.

The recess 213 may or may not extend to an end edge of the cathode active material layer 212 near the recess 213 along the winding direction C, which is near the recess 213. The both ends of the recess 213 may extend to both edges of the cathode active material layer 212, respectively, along the winding axis X perpendicular to the winding direction C, may extend to only one edge of the cathode active material layer 212 along only one end of the winding axis X, or may not extend to the edge of the cathode active material layer 212 along both ends of the winding axis X.

Both ends of the cathode sheet 21 in the winding direction C may be provided with the first barrier layer 231, or only one end thereof may be provided with the first barrier layer 231. The end of the cathode tab 21 provided with the first barrier layer 231 may be both cathode active material layers 212 of the end to which the first barrier layer 231 is attached; the first barrier layer 231 may also be attached to only one cathode active material layer 212 at that end.

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

The first barrier layer 231 is attached to the recess 213, and may cover all of the inner surface of the recess 213 or only a part of the inner surface of the recess 213.

The first barrier layer 231 is a layered body that is blocked at the outer side of the cathode active material layer 212, the first barrier layer 231 is attached to the inner surface of the recess 213, the occurrence of cracking and powder falling of the cathode active material layer 212 in the covered region can be reduced, and the height of the first barrier layer 231 attached to the recess 213 protruding from the outer surface of the cathode active material layer 212 or the surface of the first barrier layer 231 not protruding from the cathode active material layer 212 can be reduced due to the recess 213 being recessed inward.

In the battery unit 20 provided by the embodiment of the application, the first barrier layer 231 is attached to the concave 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 occurrence of cracking and powder dropping of the pole piece due to higher protrusion of the first barrier layer 231, and further improving the capacitance of the battery unit 20. Moreover, due to the arrangement of the recess 213, the cathode active material covered by the first barrier layer 231 is correspondingly reduced, so that the amount of lithium ions extracted can be reduced, thereby being beneficial to reducing the occurrence probability of lithium precipitation and reducing the occurrence probability of short circuit of the battery cell 20.

In some embodiments of the present application, as shown in fig. 3, the case 1 includes an end cap 11 and a case 12, the case 12 has a receiving cavity and an opening, the electrode assembly 2 is disposed in the receiving cavity, the end cap 11 closes the opening of the case 12, and the end cap 11 or any wall surface of the case 12 is provided with a post 4, and the post 4 is connected to a tab 25 of the electrode assembly 2 for inputting or outputting electric power.

The end cap 11 refers to a member that is covered at the opening of the case 12 to isolate the inner environment of the battery cell 20 from the outer environment. Without limitation, the shape of the end cap 11 may be adapted to the shape of the housing 12 to fit the housing 12. Optionally, the end cover 11 may be made of a material (such as an aluminum alloy) with a certain hardness and strength, so that the end cover 11 is not easy to deform when being extruded and collided, so that the battery cell 20 can have higher structural strength, and the safety performance can be improved. The electrode post 4 is electrically connected to the electrode assembly 2 for outputting or inputting electric power from the battery cell 20.

In some embodiments of the present application, as shown in fig. 3, the end cover 11 may further be provided with a pressure release mechanism 3 for releasing the internal pressure when the internal pressure or temperature of the battery cell 20 reaches a threshold value, and a protective patch of the pressure release mechanism is attached to the outer side of the pressure release mechanism 3. The material of the end cap 11 may be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which is not particularly limited in the embodiment of the present application. In some embodiments of the application, an insulating structure may also be provided on the inside of the end cap 11, which may be used to isolate electrical connection components within the housing 12 from the end cap 11 to reduce the risk of short circuits. By way of example, the insulating structure may be plastic, rubber, or the like.

The case 12 is an assembly for cooperating with the end cap 11 to form an internal environment of the battery cell 20, wherein the formed internal environment may be used to accommodate the electrode assembly 2, electrolyte, and other components. The case 12 and the end cap 11 may be separate components, and an opening may be provided in the case 12, and the interior of the battery cell 20 may be formed by covering the opening with the end cap 11 at the opening. It is also possible to integrate the end cap 11 and the housing 12, but specifically, the end cap 11 and the housing 12 may form a common connection surface before other components are put into the housing, and when the interior of the housing 12 needs to be sealed, the end cap 11 is then covered with the housing 12. The housing 12 may be of various shapes and sizes, such as rectangular parallelepiped, cylindrical, hexagonal prism, etc. Specifically, the shape of the case 12 may be determined according to the specific shape and size of the electrode assembly 2. The material of the housing 12 may be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which is not particularly limited in the embodiment of the present application.

In some embodiments, both ends of the cathode sheet 21 in the winding direction C are provided with a first barrier layer 231. In some embodiments, the feeding end of the cathode pole piece 21 wound into the innermost ring of the electrode assembly 2 is provided with a first barrier layer 231, and the winding end positioned at the outermost ring is not provided with the first barrier layer 231. In some embodiments, the feeding end of the cathode pole piece 21 wound into the innermost ring of the electrode assembly 2 is not provided with the first barrier layer 231, and the winding end positioned at the outermost ring is provided with the first barrier layer 231.

In some embodiments of the present application, as shown in fig. 5, a second barrier layer 232 is attached to an end surface of at least one end of the cathode active material layer 212 in the winding direction C.

The second barrier layer 232 may cover a portion 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. The cathode active material layer 212 is covered with the second barrier layer 232 at both end surfaces in the winding direction C, or the cathode active material layer 212 is covered with the second barrier layer 232 at one end surface in the winding direction C.

In this way, the end surface of the cathode active material layer 212 is covered with the second blocking layer 232, so that the active material on the end surface covered by the second blocking layer can be blocked from falling, and the occurrence rate of powder falling at the cut end is reduced to a greater extent.

In some embodiments of the present application, as shown in fig. 5 and 6, the recess 213 extends to an end edge of the cathode active material layer 212 near the recess 213 in the winding direction C, and the first barrier layer 231 and the second barrier layer 232 at the same end of the cathode tab 21 are connected.

The recess 213 extends to an end edge of the cathode active material layer 212 near the recess 213 in the winding direction C such that the recess 213 is closer to the end surface of the cathode active material layer 212, such that the first barrier layer 231 is closer to the end surface of the cathode active material layer 212, and the first barrier layer 231 and the second barrier layer 232 are connected to each other to more comprehensively block the surface at the cut end, thereby reducing the probability of powder falling at the cut end to a greater extent.

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

In some embodiments of the present application, as shown in fig. 5, the second barrier layer 232 is also attached to one end face of the cathode current collector 211 in the winding direction C.

Illustratively, as shown in fig. 6, one end surface of the cathode active material layer 212 in the winding direction C is a first end surface 2121, one end surface of the cathode current collector 211 in the winding direction C is a second end surface 2111, the first end surface 2121 and the second end surface 2111 are located at the same end of the cathode tab 21, as shown in fig. 5, a 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.

In this way, the second blocking layer 232 can block the end surface of the cathode active material layer 212 from powder falling, and can also block the end surface of the cathode current collector 211 from metal scraps, so that the probability that the metal scraps puncture the separator 24 is reduced, and the probability of short circuit is reduced.

In some embodiments of the present application, as shown in fig. 5 and 6, both cathode active material layers 212 of the same end of the cathode tab 21 in the winding direction C have recesses 213.

Both cathode active material layers 212 at the same end of the cathode tab 21 in the winding direction C have a recess 213, and a first barrier layer 231 is attached within the recess 213, that is, both cathode active material layers 212 at the same end of the cathode tab 21 in the winding direction C have a first barrier layer 231 attached.

Thus, the first barrier layer 231 is attached to both sides of the same end, so that the occurrence rate of powder falling at the cutting end is further reduced.

In some embodiments of the present application, as shown in fig. 5 and 6, two concave portions 213 located at the same end of the cathode tab 21 are a first concave portion 213a and a second concave portion 213b, respectively, a first barrier layer 231 attached to the first concave portion 213a and a first barrier layer 231 attached to the second concave portion 213b are connected by a second barrier layer 232, and the second barrier layer 232 is attached to an end surface of the cathode tab 21 near one end of the first concave portion 213a and the second concave portion 213b in the winding direction C.

As illustrated in fig. 5, the first barrier layer 231 attached to the first recess 213a, the first barrier layer 231 attached to the second recess 213b, and the second barrier layer 232 connected between the two first barrier layers 231 are formed as an integrally formed barrier 23, that is, one end of the barrier 23 is attached to one first recess 213a, the barrier 23 bypasses and is attached to the end surface of the cathode tab 21, and the other end of the barrier 23 is attached to the other first recess 213a.

In this way, the tightness of the coverage of the two connected first barrier layers 231 and second barrier layers 232 to the cut-off ends of the cathode pole piece 21 is high, and the surfaces of the cut-off ends are more comprehensively blocked, so that the occurrence probability of powder falling at the cut-off ends is reduced to a greater extent.

In some embodiments of the present application, the opposite sides of the two ends of the cathode sheet 21 along the winding direction C are provided with the concave portions 213, the two concave portions 213 located at the same end of the cathode sheet 21 and the end face of the end are attached to the same barrier 23, the barrier 23 includes two first barrier layers 231 and a second barrier layer 232 connected between the two first barrier layers 231, the two first barrier layers 231 are respectively attached to the two concave portions 213, and the second barrier layer 232 is attached to the end face of the cathode sheet 21.

In this way, both cut ends of the cathode tab 21 are covered by the blocking member 23, and metal scraps and powder falling from the cut ends of the cathode current collector 211 are blocked to a greater extent. Moreover, the cathode plate 21 has more concave portions 213, so that the cathode active materials at the two cut ends of the cathode plate 21 are correspondingly reduced, and the amount of lithium ions extracted can be reduced, thereby being beneficial to reducing the occurrence probability of lithium precipitation and reducing the occurrence probability of short circuit of the battery cells 20.

In some embodiments of the present application, the depressions 213 extend to both edges of the cathode active material layer 212, respectively, along the winding axis direction X perpendicular to the winding direction C.

In this way, the area of the recess 213 is larger, the cathode active material at the cut end is reduced more, and the amount of lithium ion extraction is reduced more, so that the probability of occurrence of lithium precipitation is reduced, and the probability of occurrence of short circuit of the battery cell 20 is reduced from the beginning. Moreover, the larger area of the recess 213 is beneficial to making the area covered by the first blocking layer 231 larger, and further blocking the cut end of the cathode current collector 211 from metal scraps and powder.

In some embodiments of the present application, both ends of the first barrier layer 231 attached to the first recess 213a in the winding axis direction X respectively exceed both edges of the first recess 213a, both ends of the first barrier layer 231 attached to the second recess 213b in the winding axis direction X respectively exceed both edges of the second recess 213b, and a portion of the first barrier layer 231 attached to the first recess 213a exceeding an edge of the first recess 213a and a portion of the first barrier layer 231 attached to the second recess 213b exceeding an edge of the second recess 213b are connected to each other.

Thus, the area of the cathode active material layer 212 covered by the first barrier layer 231 is larger, the first barrier layer 231 is more comprehensive to the coverage of the cut end, the probability of lithium precipitation phenomenon can be better reduced, in addition, the exceeding parts are mutually connected, the attachment firmness of the first barrier layer 231 and the cathode pole piece 21 is improved, and the effects of blocking metal scraps and powder dropping are improved.

In some embodiments of the present application, both ends of the first barrier layer 231 attached to the first recess 213a in the winding axis direction X respectively extend beyond both edges of the first recess 213a, both ends of the first barrier layer 231 attached to the second recess 213b in the winding axis direction X respectively extend beyond both edges of the second recess 213b, and a portion of the first barrier layer 231 attached to the first recess 213a that extends beyond the edges of the first recess 213a and a portion of the first barrier layer 231 attached to the second recess 213b that extends beyond the edges of the second recess 213b are bonded to each other.

So, the area of the cathode active material layer 212 covered by the first barrier layer 231 is larger, the first barrier layer 231 is more comprehensive to the coverage of the cut end, the probability of lithium precipitation phenomenon can be better reduced, the exceeding parts are mutually bonded, the firmness of the attachment of the first barrier layer 231 and the cathode pole piece 21 is improved, the effect of blocking metal scraps and powder dropping is improved, the exceeding parts of the two first barrier layers 231 are mutually connected, and the interference of the exceeding parts to the separator 24 and the anode pole piece 22 can be reduced.

In some embodiments of the present application, as shown in fig. 8, at least one end of the cathode sheet 21 in the winding direction C is provided with a third barrier layer 233, and at least one of opposite end surfaces of the cathode sheet 21 is attached with the third barrier layer 233 in the winding axis X perpendicular to the winding direction C.

In this way, the end face of the cathode plate 21 along the winding axis X is covered with the third blocking layer 233, which can block the active material and metal scraps of the end face covered by the third blocking layer from falling, thereby reducing the probability of powder and metal scraps of the cut end to a greater extent.

In some embodiments of the present application, the two recesses 213 at the same end of the cathode tab 21 are a first recess 213a and a second recess 213b, respectively, and the first barrier layer 231 attached to the first recess 213a and the first barrier layer 231 attached to the second recess 213b are connected by the first barrier layer 231.

In this way, the tightness of the coverage of the connected two first barrier layers 231 and third barrier layers 233 to the cut end of the cathode pole piece 21 is high, and the surface of the cut end is more comprehensively blocked, so that the occurrence probability of powder falling at the cut end is reduced to a greater extent.

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

In some embodiments of the present application, the depth value of the recess 213 is not less than the thickness value of the first barrier layer 231 in the thickness direction of the cathode tab 21.

In this way, the first barrier layer 231 does not protrude from the outer surface of the cathode pole piece 21, so that the occurrence probability of cracking and powder dropping at the positions of the cathode pole piece 21 and the anode pole piece 22 corresponding to the protruding positions is reduced to a greater extent, and the capacitance of the battery cell 20 is further improved.

Illustratively, the depth value of the recess 213 in the thickness direction of the cathode tab 21 is equal to the thickness value of the first barrier layer 231 such 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 tab 21. Therefore, the outer surface of the cathode pole piece 21 has no protruding structure, and the occurrence probability of pole piece cracking, powder falling and other problems caused by local stress caused by the protruding structure is better reduced.

In some embodiments of the present application, the first barrier layer 231 includes a base material layer and a glue layer attached to one surface of the base material layer, and the base material layer is adhered to the cathode tab 21 through the glue layer.

In this way, the first barrier layer 231 is attached to the recess 213 of the cathode active material layer 212 by adhesion, and the adhesion work is simple and the work efficiency is high.

In some embodiments of the present application, the second barrier layer 232 includes a base material layer and a glue layer attached to one surface of the base material layer, and the base material layer is adhered to the cathode sheet 21 through the glue layer.

In this way, the second barrier layer 232 is attached to the end face of the cathode sheet 21 in the winding direction C by adhesion, and the adhesion work is simple and the work efficiency is high.

In some embodiments of the present application, the third barrier layer 233 includes a base material layer and a glue layer attached to one surface of the base material layer, and the base material layer is adhered to the cathode tab 21 through the glue layer.

In this way, the third barrier layer 233 is attached to the end face of the cut end of the cathode sheet 21 in the winding axis direction X by adhesion, and the adhesion work is simple and the work efficiency is high.

In some embodiments of the present application, the substrate layer is a combination of any one or more of polyvinyl chloride, polyethylene, polypropylene, hexafluoropropylene-vinylidene fluoride copolymer, tetrafluoropropene-vinylidene fluoride copolymer, trifluorochloropropene-vinylidene fluoride copolymer, polyethylene terephthalate, polyimide, polyetherimide, polycarbonate, polystyrene, polyphenylene sulfide, polyvinylidene fluoride copolymer, polyarylate, fiber, nylon, nonwoven fabric.

In some embodiments of the present application, the subbing layer is formed from any one or more of an acrylic resin, an acrylic-acrylate copolymer, a butadiene-styrene copolymer, a styrene-acrylic copolymer, a styrene-acrylate copolymer, an ethylene-vinyl acetate copolymer, an acrylic grafted polyethylene, a maleic anhydride grafted polyethylene, an acrylic grafted polypropylene, a maleic anhydride grafted polypropylene, a polyvinylidene fluoride, a carboxymethyl cellulose, a polyimide, a polyetherimide, a polyethylene terephthalate, a styrene-isoprene-styrene copolymer rubber, an ethylene-vinyl acetate copolymer bisphenol a type epoxy resin, an ethylene-vinyl acetate copolymer bisphenol F type epoxy resin, a glycerol ether type epoxy resin, a glycerol ester type epoxy resin, a silicone type resin, a polyurethane, and a styrene-isoprene-styrene copolymer.

The above-mentioned materials are easily available and have excellent adhesion, and can firmly adhere the base material layer to the inner surface of the recess 213.

As shown in fig. 5, the barrier 23 includes two first barrier layers 231 and a second barrier layer 232 connected between the two first barrier layers 231, and the barrier 23 is formed as a whole, that is, the second barrier layer 232 is also attached by adhesion, and the composition structure of the second barrier layer 232 is the same as that of the first barrier layer 231, which is not described herein.

In some embodiments of the present application, as shown in fig. 5, a dimension L of the first barrier layer 231 along the winding direction C is in a range of 5um to 10 um.

For example, the dimension L of the first barrier layer 231 in 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.

Therefore, the size of the first barrier layer 231 along the winding direction C is limited within the range of 5 um-10 um, so that the size of the part covered by the first barrier layer 231 is proper, the part easy to fall powder is covered, the probability of falling powder at the cutting end is reduced, and the capacitance of the battery cell 20 is not influenced due to the too large covered area.

In some embodiments of the present application, as shown in fig. 5, the thickness T1 of the first barrier layer 231 is 10 μm to 20 μm.

As shown in fig. 5, the thickness T1 of the first barrier layer 231 may 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、20μm.

Therefore, the thickness of the first barrier layer 231 is limited within the range of 10 μm to 20 μm, so that the thickness of the first barrier layer 231 is suitable, the first barrier layer 231 can be attached in the concave part 213 without protruding, and the toughness and the strength of the first barrier layer 231 within the thickness range are both higher, so that the occurrence probability of pole piece cracking or active substance falling can be well reduced.

In some embodiments of the present application, as shown in fig. 6, the dimension T2 of the recess 213 in the thickness direction of the cathode sheet 21 is in the range of 10 μm to 20 μm.

Illustratively, the dimension T2 of the recess 213 in the thickness direction of the cathode sheet 21 may 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、20μm.

In this way, the depth of the recess 213 is made appropriate, the amount of reduction of the active material of the cathode tab 21 is made appropriate, and the first barrier layer 231 attached to the recess 213 is made not to protrude from the outer surface of the cathode tab 21, thereby contributing to a reduction in the occurrence of tab cracking or active material falling.

In some embodiments of the present application, as shown in fig. 7, the dimension W2 of the first barrier layer 231 is 10mm to 24mm along the winding axis X perpendicular to the winding direction C.

As shown in fig. 7, the dimension W2 of the first barrier layer 231 along the winding axis X perpendicular to the winding direction C may 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.

In this way, the dimension W2 of the first barrier layer 231 along the winding axial direction X is limited within a range of 10mm to 24mm, so that the dimension W2 of the first barrier layer 231 is suitable, and the cathode active material layer 212 with a large enough area can be covered, thereby well reducing the occurrence probability of cracking of the pole piece or falling of the active material.

Illustratively, as shown in fig. 7, the dimension W1 of the cathode sheet 21 is in the range of 6mm to 21mm along the winding axis X perpendicular to the winding direction C. Along a winding axis direction X perpendicular to the winding direction C, a dimension W2 of the first barrier layer 231 is 10mm to 24mm. In this way, the first barrier layer 231 is convenient to extend beyond the two edges of the cathode pole piece 21 along the winding axial direction X, and the extending dimension is suitable, so that the first barrier layer 231 covers the cutting end more comprehensively, and the occurrence probability of the lithium precipitation phenomenon can be better reduced.

A second aspect of the application provides a battery device comprising at least one battery cell 20 provided in the first aspect.

Since the battery device includes the battery cell 20 provided in the first aspect, and the battery cell 20 has a large battery capacity and a low risk of short circuit, the battery device has a large battery capacity and a low risk of short circuit.

In some embodiments, the battery device may be a battery pack 100, the battery pack 100 including a battery case 10 and one or more battery cells 20, the battery cells 20 being accommodated in the battery case 10.

In some embodiments, the battery device may be an energy storage device including an energy storage container, an energy storage electrical cabinet, or the like.

A third aspect of the application provides an electrical device comprising the battery cell 20 provided in the first aspect or the battery device provided in the second aspect for providing electrical energy.

Since the electric 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 a large battery capacity and a low risk of short circuit, the electric device has a large battery capacity and a low risk of short circuit.

A fourth aspect of the present application provides a battery cell manufacturing method, as shown in fig. 9, comprising:

s1, providing a cathode pole piece, an anode pole piece, a first barrier layer and a second barrier layer,

The cathode sheet 21 includes a cathode current collector 211 and a cathode active material layer 212, and the cathode active material layer 212 is provided on opposite surfaces of the cathode current collector 211 in a thickness direction of the cathode current collector 211;

S2, attaching a first barrier layer and a second barrier layer to the feeding end of the cathode pole piece;

s3, winding the cathode pole piece and the anode pole piece along the winding direction;

S4, cutting off the cathode pole piece, and attaching a first barrier layer and a second barrier layer at the winding end of the cathode pole piece to form an electrode assembly;

And S5, providing a shell, and loading the electrode assembly into a containing cavity of the shell to form a battery cell.

At least one of the two cathode active material layers 212 at the same end of the cathode sheet 21 is provided with a first barrier layer 231 along the winding direction C, a surface of the cathode active material layer 212 facing away from the cathode current collector 211 is recessed inward to form a recess 213, the first barrier layer 231 is attached in the recess 213, and a second barrier layer 232 is attached to an end surface of the cathode active material layer 212 along the winding direction C.

In the battery cell 20 manufactured by the method for manufacturing a battery cell according to the embodiment of the present application, the first barrier layer 231 is attached to the concave 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 or the first barrier layer 231 does not protrude can be reduced, and the probability of occurrence of cracking and powder dropping of the electrode sheet due to the higher protrusion of the first barrier layer 231 can be reduced, thereby improving the electric capacity of the battery cell 20. Moreover, due to the arrangement of the concave portion 213, the cathode active material covered by the first blocking layer 231 is correspondingly reduced, so that the amount of lithium ions extracted can be reduced, thereby being beneficial to reducing the occurrence probability of lithium precipitation, reducing the occurrence 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 blocking layer 232, so that the falling of the active material on the end face covered by the second blocking layer can be blocked, thereby reducing the occurrence probability of powder falling at the cut end to a greater extent.

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

As a specific example, the battery cell 20 includes a case 1 and an electrode assembly 2, the case 1 having a receiving cavity; the electrode assembly 2 is arranged in the accommodating cavity, the electrode assembly 2 is formed by winding a laminated body comprising a cathode pole piece 21 and an anode pole piece 22 along a winding direction C, the cathode pole piece 21 comprises a cathode current collector 211 and a cathode active material layer 212 arranged on two surfaces of the cathode current collector 211 opposite to each other along the thickness direction of the cathode current collector 211, the surfaces of the two ends of the cathode active material layer 212 along the winding direction C, which are opposite to the cathode current collector 211, are inwards recessed to form a recessed part 213, the recessed part 213 extends to one end edge of the cathode active material layer 212, which is close to the recessed part 213, along the winding direction C, and the recessed part 213 extends to two edges of the cathode active material layer 212 along the winding axial direction X respectively, one end of the innermost ring of the cathode pole piece 21, which is wound into the electrode assembly 2, is a feeding end, one end of the outermost ring is a winding end, the winding end and the winding end are respectively attached with a blocking piece 23, a part (a first blocking layer 231) of the blocking piece 23 is adhered to one concave part 213 of the feeding end or the winding end, the other part (a second blocking layer 232) bypasses and is adhered to the end face of the winding end, the other part (the other first blocking layer 231) is adhered to the other concave part 213 of the winding end, the blocking piece 23 is not protruded out of the outer surface of the cathode pole piece 21, so that the cathode pole piece 21 is not locally stressed due to the protrusion of the blocking piece 23, the probability of occurrence of pole piece cracking and powder dropping and the like caused by the protrusion edge due to local stress extrusion is reduced, and due to the arrangement of the concave part 213, the cathode active material of the cathode active material layer 212 is reduced, the amount of lithium ion extraction is reduced, thereby being beneficial to reducing the occurrence of lithium ion extraction, the probability of short-circuiting of the battery cells 20 is reduced from the beginning.

The portions (first barrier layer 231) of the barrier 23 adhered to the two opposite concave portions 213 at the same end respectively protrude beyond the edges of the concave portions 213 along the winding axis X, and the protruding portions are adhered to each other, so that the protruding portions of the barrier 23 are reduced from adhering to the separator 24 or the anode electrode sheet 22, resulting in interference in the winding process.

The above embodiments are only for illustrating the technical solution of the present application, and not for limiting the same; although the application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the application, and they should be included in the scope of the present application. In particular, the technical features mentioned in the respective embodiments may be combined in any manner as long as there is no structural conflict.

Claims

1. A battery cell, comprising:

A housing having a receiving cavity;

An electrode assembly disposed in the receiving chamber, the electrode assembly being formed by winding a laminate including a cathode sheet and an anode sheet in a winding direction, the cathode sheet including a cathode current collector and a cathode active material layer disposed on opposite surfaces of the cathode current collector in a thickness direction of the cathode current collector,

Along the winding direction, at least one end of the cathode plate is provided with a first blocking layer, at least one of the two cathode active material layers at the same end of the cathode plate is provided with the first blocking layer,

The surface of the cathode active material layer, which is opposite to the cathode current collector, is inwards recessed to form a recessed part, and the first barrier layer is attached in the recessed part;

A second barrier layer is attached to an end face of at least one end of the cathode active material layer in the winding direction.

2. The battery cell according to claim 1, wherein the second barrier layer is further attached to an end face of the cathode current collector in the winding direction.

3. The battery cell according to claim 1, wherein the recess extends in the winding direction to an end edge of the cathode active material layer near the recess,

The first barrier layer and the second barrier layer positioned at the same end of the cathode plate are connected.

4. The battery cell according to claim 1, wherein both of the cathode active material layers at the same end of the cathode sheet in the winding direction have the concave portion.

5. The battery cell according to claim 4, wherein the two concave portions at the same end of the cathode sheet are a first concave portion and a second concave portion, respectively, the first blocking layer attached to the first concave portion and the first blocking layer attached to the second concave portion are connected by a second blocking layer attached to an end face of the cathode sheet near one end of the first concave portion and the second concave portion in the winding direction.

6. The battery cell according to claim 4 or 5, wherein the concave portions extend to both edges of the cathode active material layer, respectively, in a winding axis direction perpendicular to the winding direction.

7. The battery cell according to claim 6, wherein the two concave portions located at the same end of the cathode sheet are a first concave portion and a second concave portion, respectively, both ends of the first barrier layer attached to the first concave portion in the winding axis direction exceed both edges of the first concave portion, respectively, both ends of the first barrier layer attached to the second concave portion in the winding axis direction exceed both edges of the second concave portion, respectively, and a portion of the first barrier layer attached to the first concave portion beyond an edge of the first concave portion and a portion of the first barrier layer attached to the second concave portion beyond an edge of the second concave portion are connected to each other.

8. The battery cell according to claim 4, wherein at least one end of the cathode sheet in the winding direction is provided with a third barrier layer to which at least one of opposite end faces of the cathode sheet is attached in a winding axis direction perpendicular to the winding direction.

9. The battery cell of claim 8, wherein the two recesses at the same end of the cathode sheet are a first recess and a second recess, respectively, the first barrier layer attached to the first recess and the first barrier layer attached to the second recess being connected by the third barrier layer.

10. The battery cell according to any one of claims 1 to 5, wherein a depth value of the recess is not less than a thickness value of the first barrier layer in a thickness direction of the cathode sheet.

11. The battery cell of claim 1, wherein the first barrier layer comprises a substrate layer and a glue layer attached to a surface of the substrate layer, the substrate layer being adhered to the cathode electrode sheet by the glue layer.

12. The battery cell of claim 1, wherein the second barrier layer comprises a substrate layer and a glue layer attached to a surface of the substrate layer, the substrate layer being adhered to the cathode electrode sheet by the glue layer.

13. The battery cell of claim 8, wherein the third barrier layer comprises a substrate layer and a glue layer attached to a surface of the substrate layer, the substrate layer being adhered to the cathode electrode sheet by the glue layer.

14. The battery cell of any one of claims 11 to 13, wherein the substrate layer is at least one of polyvinyl chloride, polyethylene, polypropylene, hexafluoropropylene-vinylidene fluoride copolymer, tetrafluoropropene-vinylidene fluoride copolymer, trifluorochloropropene-vinylidene fluoride copolymer, polyethylene terephthalate, polyimide, polyetherimide, polycarbonate, polystyrene, polyphenylene sulfide, polyvinylidene fluoride copolymer, polyarylate, fiber, nylon, nonwoven fabric.

15. The battery cell of any one of claims 11 to 13, wherein the subbing layer is at least one of an acrylic resin, an acrylic-acrylate copolymer, a butadiene-styrene copolymer, a styrene-acrylic copolymer, a styrene-acrylate copolymer, an ethylene-vinyl acetate copolymer, an acrylic grafted polyethylene, a maleic anhydride grafted polyethylene, an acrylic grafted polypropylene, a maleic anhydride grafted polypropylene, polyvinylidene fluoride, carboxymethyl cellulose, polyimide, polyetherimide, polyethylene phthalate, styrene-isoprene-styrene copolymer rubber, an ethylene-vinyl acetate copolymer bisphenol a type epoxy resin, an ethylene-vinyl acetate copolymer bisphenol F type epoxy resin, a glycerol ether type epoxy resin, a glyceride type epoxy resin, a silicone type resin, polyurethane, a styrene-isoprene-styrene copolymer.

16. The battery cell of any one of claims 1-5, wherein the first barrier layer has a dimension in the winding direction in the range of 5um to 10 um.

17. The battery cell of any one of claims 1 to 5, wherein the first barrier layer has a thickness of 10 μιη to 20 μιη.

18. The battery cell of any one of claims 1 to 5, wherein the first barrier layer is 10mm to 24mm in size along a winding axis perpendicular to the winding direction.

19. A battery device, characterized by comprising:

at least one battery cell according to any one of claims 1 to 18.

20. An electrical device comprising the battery cell of any one of claims 1 to 18 or the battery device of claim 19 for providing electrical energy.

21. A method for manufacturing a battery cell, comprising: