CN217768540U - Battery cell, battery and power consumption device - Google Patents

Abstract

The application provides a battery monomer, battery and power consumption device. The battery cell includes a case, an electrode assembly, and at least one restraining member. An electrode assembly is disposed within the housing, the electrode assembly including a body portion having first and second ends oppositely disposed in an axial direction of the electrode assembly. At least one tie sets up between the week side of main part and the shell, and wherein, at least one tie includes first tie, and the minimum interval of first tie and first end is less than the minimum interval of first tie and second end. The battery monomer that this application embodiment provided can improve the uniformity of the free electrode subassembly internal stress of battery to improve the stability and the uniformity of electrode subassembly charge-discharge performance, and then improve the free cycle life of battery.

Description

Battery cell, battery and power consumption device

Technical Field

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

Background

Batteries are widely used in electronic devices such as mobile phones, notebook computers, battery cars, electric automobiles, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, electric tools, and the like. The battery monomer can include a cadmium-nickel battery monomer, a hydrogen-nickel battery monomer, a lithium ion battery monomer, a secondary alkaline zinc-manganese battery monomer and the like.

In the development of the battery cell technology, in addition to improving the performance of the battery cell, how to electrically improve the service life of the battery cell is also a considerable problem. Improving the service life of the battery cell has a significant impact on energy conservation. Therefore, how to increase the service life of the battery cell is a technical problem of continuous improvement in the battery cell technology.

SUMMERY OF THE UTILITY MODEL

The application provides a single battery, battery and power consumption device can improve single battery's life.

In a first aspect, embodiments of the present application provide a battery cell including a housing, an electrode assembly, and at least one restraining member; an electrode assembly disposed within the case, the electrode assembly including a main body portion having first and second ends oppositely disposed in an axial direction of the electrode assembly; at least one tie sets up between the week side of main part and the shell, and wherein, at least one tie includes first tie, and the minimum interval of first tie and first end is less than the minimum interval of first tie and second end.

The battery monomer that this application embodiment provided, the minimum interval through setting up first constraint piece and first end is less than first constraint piece to the minimum interval of second end, then along with the increase of electrode subassembly circulation charge-discharge number of times, first constraint piece is to the skew cross section setting of electrode subassembly's constraint power distribution, make the internal stress of electrode subassembly skew well cross section region obtain the reinforcing, so can balance electrode subassembly self internal stress difference, make electrode subassembly's internal stress distribution unanimous as far as possible, improve electrode subassembly charge-discharge performance's stability and uniformity, and then improve battery monomer's cycle life.

In some embodiments, the peripheral side of the electrode assembly has a first attachment region, the first tie attached to at least a portion of the first attachment region; the first attachment region starts from the first end and extends in the axial direction, and the dimension of the first attachment region in the axial direction is smaller than 1/3 of the dimension of the main body portion in the axial direction. Therefore, the internal stress difference of the electrode assembly is further reduced, and the consistency of the charging and discharging performance of the electrode assembly is improved.

In some embodiments, the electrode assembly includes a first electrode piece including a first active material layer located at the main body portion, the first active material layer including a base region and a thinned region, the thinned region having a thickness less than a thickness of the base region, the thinned region being located at a side of the base region near the first end in the axial direction; in the axial direction, the first binding piece and the thinning area are arranged in a staggered mode. The thin area can reduce the stress concentration at the edge of the thin area far away from the base area, so that the risk of the first pole piece breaking is reduced. The first binding piece and the thinning area are arranged in a staggered mode, so that the risk that the thinning area is greatly deformed and damaged due to the first binding piece can be reduced.

In some embodiments, the first restraint is spaced from the thinning region by 1mm to 2mm in the axial direction. Therefore, the risk that the first constraint piece generates constraint force on the thinning area can be further reduced, and the risk that the electrode assembly corresponding to the thinning area is damaged due to large deformation is reduced.

In some embodiments, the at least one tie down includes a second tie down having a minimum spacing from the second end that is less than a minimum spacing from the first end. By the arrangement, the uniformity of the stress in the electrode assembly can be further improved, so that the uniformity of the charging and discharging performance of the electrode assembly is improved.

In some embodiments, the peripheral side of the electrode assembly has a second attachment region, the second tie being attached to at least a portion of the second attachment region; the second attachment area takes the second end as a starting end and extends along the axial direction, and the size of the second attachment area along the axial direction is smaller than 1/3 of the size of the main body part along the axial direction. Further reducing the difference of the internal stress of the electrode assembly and improving the consistency of the charging and discharging performance of the electrode assembly.

In some embodiments, the body portion has a mid-section between the first end and the second end, and the second and first tethers are axially symmetrically disposed about the mid-section. The uniformity of the stress distribution in the electrode assembly can be further improved, and the uniformity of the charging and discharging performance of the electrode assembly can be further improved.

In some embodiments, the at least one tie down includes a third tie down, the body portion having a mid-section between the first end and the second end, the third tie down covering the mid-section. In this manner, the restraint is achieved to balance the effects of stress within the electrode assembly while improving the stability of the electrode assembly within the housing.

In some embodiments, the at least one tie includes a third tie, the body portion having a mid-section between the first end and the second end, the third tie being attached to an area between the mid-section and the first end, and the third tie being located on a side of the first tie proximate the second end. According to the arrangement, the structural stability of the electrode assembly can be improved while the consistency of the charging and discharging performance of the electrode assembly is improved.

In some embodiments, the first anchor has a thickness greater than a thickness of the third anchor. Therefore, the consistency of the internal stress of the electrode assembly is improved, and the consistency of the charging and discharging performance of the electrode assembly is improved.

In some embodiments, the body portion has a mid-section at the first end and the second end; the at least one tie down includes a fourth tie down attached to an area between the mid-section and the second end, and the fourth tie down is located on a side of the second tie down proximate the first end. Thus, the uniformity of stress in the electrode assembly is further improved.

In some embodiments, the at least one tie includes a third tie, and the fourth tie is symmetrically disposed about the mid-section with the third tie. Thus, the uniformity of the charge and discharge performance of the electrode assembly can be still further improved.

In some embodiments, the binder is configured to swell upon absorbing the electrolyte. Therefore, the binding action of the binding piece on the electrode assembly can be ensured, and the smooth proceeding of the shell entering operation of the binding piece and the electrode assembly in the assembling process is facilitated.

In some embodiments, the material of the tie includes at least one of thermoplastic polyurethane, dextran gel, and hydroxyl terminated polybutadiene-polyurethane. Therefore, the proportion of each component in the material of the binding piece is reasonably distributed, so that the binding piece has proper thickness after being expanded when meeting the electrolyte, and the binding piece formed after being expanded has proper binding force on the electrode assembly.

In some embodiments, the tie has a first free end and a second free end along a circumferential direction of the electrode assembly; the restraint includes an overlapping portion disposed between the first free end and the second free end, and a central angle α of the overlapping portion satisfies, in a circumferential direction of the electrode assembly: alpha is less than or equal to 30 degrees. Thus, it is advantageous to secure a binding force of the binding member to the electrode assembly and to facilitate the installation of the binding member.

In some embodiments, the tie down has a first free end and a second free end spaced apart along a circumferential direction of the electrode assembly; the main body part is provided with an exposed area which is positioned between the first free end and the second free end and exposed outside the binding piece; the central angle beta of the exposed area along the circumferential direction of the electrode assembly satisfies that beta is less than or equal to 180 degrees. When guaranteeing that the constraint piece provides certain restraint example for electrode subassembly, be convenient for electrolyte through naked district entering electrode subassembly inside, improve the infiltration nature of electrolyte to electrode subassembly. In addition, the exposed area can reserve space for the expansion of the electrode assembly, and the risk of damage to the electrode assembly due to expansion deformation is reduced.

In some embodiments, the tie down includes a plurality of first portions disposed at intervals along a circumference of the electrode assembly. The constraint force of the constraint piece on the electrode assembly is guaranteed, the possibility of shaking of the electrode assembly is reduced, and meanwhile gaps of the plurality of first parts along the circumferential direction of the electrode assembly can be used as electrolyte circulation channels, and the mobility of electrolyte is improved. In addition, the gap between the first portions may provide a space for expansion of the electrode assembly, further reducing the risk of damage to the electrode assembly due to expansion deformation.

In some embodiments, the electrode assembly includes a first pole piece wound in a plurality of turns; in the circumferential direction of the electrode assembly, the binding piece and the tail end of the first pole piece at the outermost ring are arranged in a staggered mode. Therefore, the risk that the electrode assembly generates stress concentration at the tail end of the first pole piece is reduced, and the risk that the electrode assembly is deformed and damaged is reduced.

In a second aspect, embodiments of the present application provide a battery, including a battery cell as in any of the embodiments of the first aspect.

According to the battery provided by the embodiment of the application, since the battery cell provided by any one of the above embodiments is adopted, the same technical effects are achieved, and details are not repeated herein.

In a third aspect, an embodiment of the present application provides an electric device, including a battery as in the embodiment of the second aspect, where the battery is used to provide electric energy.

According to the power consumption device provided by the embodiment of the application, the battery provided by the embodiment of the application is adopted, so that the same technical effects are achieved, and the details are not repeated.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments of the present application will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present application, and it is obvious for a person skilled in the art to obtain other drawings based on the drawings without any creative effort.

FIG. 1 is a schematic structural diagram of a vehicle according to an embodiment of the present disclosure;

fig. 2 is an exploded view of a battery according to an embodiment of the present disclosure;

fig. 3 is a schematic structural diagram of a battery module in a battery provided in an embodiment of the present application;

fig. 4 is an exploded view of a battery cell according to some embodiments of the present disclosure;

fig. 5 is a schematic diagram of an exploded structure of another battery cell provided in an embodiment of the present application;

fig. 6 is a schematic partial cross-sectional view illustrating an electrode assembly in a battery cell according to an embodiment of the present disclosure;

fig. 7 is an exploded view of another battery cell according to an embodiment of the present disclosure;

fig. 8 is an exploded schematic view of another battery cell provided in an embodiment of the present application;

fig. 9 is a schematic diagram illustrating an exploded structure of another battery cell according to an embodiment of the present disclosure;

fig. 10 is an exploded view of another battery cell according to an embodiment of the present disclosure;

fig. 11 is a schematic cross-sectional view of a battery cell provided in an embodiment of the present application, taken perpendicular to an axial direction;

fig. 12 is a schematic cross-sectional view of a battery cell provided in an embodiment of the present application, taken along a direction perpendicular to an axial direction;

fig. 13 is a schematic cross-sectional view of a battery cell provided in an embodiment of the present application, taken perpendicular to an axial direction;

fig. 14 is a schematic cross-sectional view of a battery cell provided in an embodiment of the present application, the cross-sectional view being perpendicular to an axial direction;

in the drawings, the figures are not drawn to scale.

Description of reference numerals:

1. a vehicle; 1a, a motor; 1b, a controller;

10. a battery; 11. a first tank portion; 12. a second tank portion;

20. a battery module;

30. a battery cell; 31. a housing; 311. a housing; 311a, an opening; 312. an end cap; 32. an electrode assembly; 32a, a first attachment region; 32b, a second attachment region; 321. a main body part; 321a, a first end; 321b, a second end; 321c, a base region; 321d, a thinning area; 321e, bare areas; 321f, middle cross section; 3211. a first pole piece; 3211a, tail end; 32111. a first active material layer; 322. a first tab; 33. a tie down; 33a, a first free end; 33b, a second free end; 33c, an overlapping portion; 33d, a first portion; 331. a first binder; 332. a second restraint; 333. a third binder; 334. a fourth restraint;

x, axial direction.

Detailed Description

Embodiments of the present application will be described in further detail below with reference to the drawings and examples. The following detailed description of the embodiments and the accompanying drawings are provided to illustrate the principles of the application and are not intended to limit the scope of the application, i.e., the application is not limited to the described embodiments.

In the description of the present application, it is to be noted that, unless otherwise specified, "a plurality" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," and the like, indicate an orientation or positional relationship that is merely for convenience in describing the application and to simplify the description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the application. Furthermore, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. "vertical" is not strictly vertical but is within the tolerance of the error. "parallel" is not strictly parallel but within the tolerance of the error.

Reference in the specification to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the specification. The appearances of the phrase 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. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.

In the description of the present application, it is also to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; may be directly connected or indirectly connected through an intermediate. The specific meaning of the above terms in the present application can be understood as appropriate by one of ordinary skill in the art.

The term "and/or" in this application is only one kind of association relationship describing the associated object, and means that there may be three kinds of relationships, for example, C and/or D, which may mean: c exists alone, C and D exist simultaneously, and D exists alone. In addition, the character "/" in this application generally indicates that the former and latter related objects are in an "or" relationship.

In the embodiments of the present application, like reference numerals denote like parts, and a detailed description of the same parts is omitted in different embodiments for the sake of brevity. It should be understood that the thickness, length, width and other dimensions of the various components in the embodiments of the present application and the overall thickness, length, width and other dimensions of the integrated device shown in the drawings are only exemplary and should not constitute any limitation to the present application.

The appearances of "a plurality" in this application are intended to mean more than two (including two).

In this application, the battery cell may include a lithium ion secondary battery cell, a lithium ion primary battery cell, a lithium sulfur battery cell, a sodium lithium ion battery cell, a sodium ion battery cell, or a magnesium ion battery cell, and the embodiment of the present application is not limited thereto. The battery cell may be a cylinder, a flat body, a rectangular parallelepiped, or other shapes, which is not limited in the embodiments of the present application. The battery cells are generally divided into three types in an encapsulation manner: the single battery of cylindricality battery, square battery monomer and laminate polymer battery monomer, this application embodiment is to this also not limited.

Reference to a battery in embodiments of the present application refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. For example, the battery referred to in the present application may include a battery module or a battery pack, etc. Batteries generally include a case for enclosing one or more battery cells. The box can avoid liquid or other foreign matters to influence the charging or discharging of battery monomer.

The battery cell comprises an electrode assembly and electrolyte, wherein the electrode assembly comprises a positive pole piece, a negative pole piece and a separator. The battery cell mainly depends on metal ions to move between the positive pole piece and the negative pole piece to work. The positive pole piece comprises a positive current collector and a positive active substance layer, and the positive active substance layer is coated on the surface of the positive current collector; the positive current collector comprises a positive current collecting part and a positive convex part protruding out of the positive current collecting part, the positive current collecting part is coated with a positive active material layer, at least part of the positive convex part is not coated with the positive active material layer, and the positive convex part is used as a positive electrode lug. Taking a lithium ion battery as an example, the material of the positive electrode current collector may be aluminum, the positive electrode active material layer includes a positive electrode active material, and the positive electrode active material may be lithium cobaltate, lithium iron phosphate, ternary lithium, lithium manganate, or the like. The negative pole piece comprises a negative pole current collector and a negative pole active substance layer, and the negative pole active substance layer is coated on the surface of the negative pole current collector; the negative current collector comprises a negative current collecting part and a negative convex part protruding out of the negative current collecting part, the negative current collecting part is coated with a negative active material layer, at least part of the negative convex part is not coated with the negative active material layer, and the negative convex part is used as a negative electrode tab. The material of the negative electrode current collector may be copper, the negative electrode active material layer includes a negative electrode active material, and the negative electrode active material may be carbon, silicon, or the like. In order to ensure that the high current can be passed through without fusing, a plurality of positive electrode tabs are stacked together, and a plurality of negative electrode tabs are stacked together. The material of the spacer may be PP (polypropylene) or PE (polyethylene). In addition, the electrode assembly may have a winding structure or a lamination structure, and the embodiment of the present application is not limited thereto.

After the inventor finds that the service life of the battery cell is low, systematic analysis and research are carried out on the structure and the working process of the battery cell, and as a result, the anode piece of the electrode assembly gradually expands along with the increase of the number of times of cyclic charge and discharge of the electrode assembly of the battery cell, and the expansion amount of the electrode assembly near the middle area is larger than that of the electrode assembly near the two end areas along the axial direction of the electrode assembly, so that the internal stress of the electrode assembly is larger near the middle area of the electrode assembly along the axial direction, and the internal stress is smaller near the two ends of the electrode assembly along the axial direction. Along with the increase of the cycle charging and discharging times of the electrode assembly, the difference of the internal stress of the middle area and the internal stress of the two ends of the electrode assembly is gradually increased, the charging and discharging performance consistency of the electrode assembly is gradually reduced, and the energy storage capacity of the corresponding battery monomer is gradually reduced, so that the service life of the battery monomer is seriously influenced.

Based on the above problems discovered by the inventor, the inventor improves the structure of the battery cell, and the technical solution described in the embodiment of the present application is applicable to the battery cell, the battery including the battery cell, and the electric device using the battery.

A battery cell provided according to an embodiment of the present application includes a case, an electrode assembly, and at least one binder. The electrode assembly is disposed within the case and includes a main body portion having first and second ends oppositely disposed in an axial direction of the electrode assembly. At least one binding piece is arranged between the peripheral side surface of the main body part and the shell. The at least one tie includes a first tie having a minimum spacing from the first end that is less than a minimum spacing from the second end.

The battery monomer that this application embodiment provided, the minimum interval through setting up first constraint piece and first end is less than the minimum interval of first constraint piece and second end, and first constraint piece is asymmetric setting for the both ends of main part promptly. The distribution of the binding force of the first binding piece on the electrode assembly deviates from the middle section of the main body part, the internal stress of the area of the main body part deviating from the middle section is enhanced due to the binding force of the first binding piece, so that the difference of the internal stress of the area and the internal stress of the area of the electrode assembly close to the middle section is balanced, the consistency of the internal stress of the electrode assembly and the consistency of the charging and discharging performance of the electrode assembly are improved, and the cycle life of the battery cell is further prolonged.

The electric device can be a vehicle, a mobile phone, a portable device, a notebook computer, a ship, a spacecraft, an electric toy, an electric tool and the like. The vehicle can be a fuel oil vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid electric vehicle or a range extending vehicle and the like; spacecraft include aircraft, rockets, space shuttles, and spacecraft, among others; the electric toys include stationary or mobile electric toys, such as game machines, electric car toys, electric ship toys, electric airplane toys, and the like; the electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools, and electric tools for railways, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, electric impact drills, concrete vibrators, and electric planers. The embodiment of the present application does not particularly limit the above power utilization apparatus.

For convenience of explanation, the following embodiments will be described with an electric device as an example of a vehicle.

As shown in fig. 1, a battery 10 is provided inside the vehicle 1. The battery 10 may be disposed at the bottom or the head or the tail of the vehicle 1. The battery 10 may be used for power supply of the vehicle 1, and for example, the battery 10 may serve as an operation power source of the vehicle 1.

The vehicle 1 may further include a controller 1b and a motor 1a. The controller 1b is used to control the battery 10 to supply power to the motor 1a, for example, for operation power demand at the time of starting, navigation, and traveling of the vehicle 1.

In some embodiments of the present application, the battery 10 may be used not only as an operating power source of the vehicle 1, but also as a driving power source of the vehicle 1, instead of or in part of fuel or natural gas, to provide driving power for the vehicle 1.

Referring to fig. 2, the battery 10 includes battery cells (not shown in fig. 2). The battery 10 may also include a case for housing the battery cells.

The box is used for holding battery monomer, and the box can be various structural style. In some embodiments, the tank may comprise a first tank portion 11 and a second tank portion 12. The first tank portion 11 and the second tank portion 12 cover each other. The first case portion 11 and the second case portion 12 together define a receiving space for receiving the battery cells. The second box portion 12 may be a hollow structure with one open end, the first box portion 11 is a plate-shaped structure, and the first box portion 11 covers the open side of the second box portion 12 to form a box body with an accommodating space; the first tank portion 11 and the second tank portion 12 may be both hollow structures with one side open. The open side of the first casing portion 11 covers the open side of the second casing portion 12 to form a casing having an accommodation space. Of course, the first tank portion 11 and the second tank portion 12 may be various shapes, such as a cylinder, a rectangular parallelepiped, and the like.

In order to improve the sealing performance of the connected first box portion 11 and second box portion 12, a sealing member, such as a sealant or a sealing ring, may be disposed between the first box portion 11 and the second box portion 12.

Assuming that the first box portion 11 covers the second box portion 12, the first box portion 11 may also be referred to as an upper box cover, and the second box portion 12 may also be referred to as a lower box body.

In the battery 10, one or more battery cells may be provided. If there are a plurality of battery cells, the plurality of battery cells may be connected in series, in parallel, or in series-parallel. The series-parallel connection means that a plurality of battery monomers are connected in series and in parallel. The plurality of battery cells may be directly connected in series or in parallel or in series-parallel, and then the whole body formed by the plurality of battery cells is accommodated in the box body, or the plurality of battery cells may be connected in series or in parallel or in series-parallel to form the battery module 20. The plurality of battery modules 20 are connected in series or in parallel or in series-parallel to form a whole, and are accommodated in the case.

In some embodiments, as shown in fig. 3, fig. 3 is a schematic structural view of the battery module 20 shown in fig. 2. In the battery module 20, there are a plurality of battery cells 30. The plurality of battery cells 30 are connected in series, in parallel, or in series-parallel to form the battery module 20. The plurality of battery modules 20 are connected in series or in parallel or in series-parallel to form a whole, and are accommodated in the case.

In some embodiments, the plurality of battery cells 30 in the battery module 20 may be electrically connected to each other through a bus member, so as to realize parallel connection, series connection or parallel connection of the plurality of battery cells 30 in the battery module 20.

Referring to fig. 4, fig. 4 is an exploded view of the battery cell 30 shown in fig. 3. The battery cell 30 provided by the embodiment of the application comprises an electrode assembly 32 and a shell 31, wherein the shell 31 is provided with a containing cavity, and the electrode assembly 32 is contained in the containing cavity.

In some embodiments, the case 31 may include a case 311 and an end cap 312, the case 311 is a hollow structure with one side open, and the end cap 312 covers the opening 311a of the case 311 and forms a sealing connection to form a sealing space for accommodating the electrode assembly 32 and the electrolyte.

When assembling the battery cell 30, the electrode assembly 32 may be placed in the case 311, the cap 312 may be fitted to the opening of the case 311, and the electrolyte may be injected into the case 311 through the electrolyte injection port of the cap 312.

In some embodiments, the housing 31 may also be used to contain an electrolyte, such as an electrolyte. The housing 31 may take a variety of configurations.

Fig. 4 shows a schematic structural diagram of a battery cell provided in an embodiment of the present application.

The housing 311 may be various shapes, such as a cylinder, a rectangular parallelepiped, or the like. The shape of the case 311 may be determined according to the specific shape of the electrode assembly 32. For example, if the electrode assembly 32 has a cylindrical structure, the case 311 may alternatively have a cylindrical structure. If the electrode assembly 32 has a rectangular parallelepiped structure, the case 311 may have a rectangular parallelepiped structure. In fig. 4, the case 311 and the electrode assembly 32 are each exemplarily a rectangular parallelepiped structure.

The material of the housing 311 may be various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc., and the embodiment of the present invention is not limited thereto.

The electrode assembly 32 accommodated in the case 311 may be one or more. In fig. 4, there are two electrode assemblies 32 accommodated in the case 311.

In some embodiments, the electrode assembly 32 further includes a positive electrode tab, a negative electrode tab, and a separator. The electrode assembly 32 may be a wound structure formed of a positive electrode tab, a separator, and a negative electrode tab by winding. The electrode assembly 32 may also be a stacked structure formed by a stacking arrangement of a positive electrode tab, a separator, and a negative electrode tab.

The positive electrode sheet may include a positive electrode current collector and a positive electrode active material layer. The positive active material layer is coated on the surface of the positive current collector. The negative electrode tab may include a negative electrode current collector and a negative electrode active material layer. The negative electrode active material layer is coated on the surface of the negative electrode current collector. The separator is arranged between the positive pole piece and the negative pole piece and used for separating the positive pole piece from the negative pole piece so as to reduce the risk of short circuit between the positive pole piece and the negative pole piece.

The tabs in the electrode assembly 32 are divided into positive and negative tabs. The positive electrode tab may be a portion of the positive electrode current collector that is not coated with the positive electrode active material layer. The negative electrode tab may be a portion of the negative electrode collector that is not coated with the negative electrode active material layer.

Fig. 5 is a schematic diagram illustrating an explosion structure of the battery cell 30 according to the embodiment of the present application.

As shown in fig. 5, a battery cell 30 provided according to an embodiment of the present application includes a case 31, an electrode assembly 32, and at least one binder 33. The electrode assembly 32 is disposed in the case 31, and the electrode assembly 32 includes a main body portion 321, and the main body portion 321 has a first end 321a and a second end 321b oppositely disposed along an axial direction X of the electrode assembly 32. And at least one binding piece 33 arranged between the peripheral side surface of the main body part 321 and the shell 31, wherein the at least one binding piece 33 comprises a first binding piece 331, and the minimum distance between the first binding piece 331 and the first end 321a is smaller than the minimum distance between the first binding piece 331 and the second end 321b.

Alternatively, the electrode assembly 32 may be cylindrical or square, and the pole pieces of the electrode assembly 32 may be wound or laminated. In the embodiment in which the electrode assembly 32 has a square shape, the surface of the main body portion 321 has an arc-shaped region and a plane region, and the axial direction X of the electrode assembly 32 may be a direction parallel to the extending direction of the arc-shaped region.

Alternatively, the electrode assembly 32 may include one tab, or may include two tabs. In embodiments where the electrode assembly 32 includes one tab, the tab may be drawn from the first end 321a of the body portion 321 or may be drawn from the second end 321b of the body portion 321. In the embodiment where the electrode assembly 32 includes two tabs, the two tabs may be respectively led out from the first end 321a and the second end 321b, or both the two tabs may be led out from the first end 321a, or both the two tabs may be led out from the second end 321b, which is not limited herein.

Alternatively, at least one of the binders 33 may include only the first binder 331 and may further include other binders 33, and the shape, structure, positional relationship with respect to the electrode assembly 32, and the like of different binders 33 may be the same as or different from those of the first binder 331.

Optionally, the number of the first binder 331 may be one, or may be multiple, and may be selected according to actual needs. In an embodiment where the first anchors 331 are plural in number, the plural first anchors 331 may be disposed along the axial direction X of the electrode assembly 32, and adjacent first anchors 331 may be disposed at intervals or may be adjacent to each other.

The peripheral side surface of the body portion 321 is a surface of the body portion between the first end 321a and the second end 321b. At least one binding piece 33 is provided between the peripheral side surface of the body 321 and the case 31, and before the battery cell 30 is charged and discharged, the binding piece 33 may be in contact with both the peripheral side surfaces of the case 31 and the body 321, or the binding piece 33 may be in contact with either the case 31 or the body 321, or the binding piece 33 may be provided at an interval from both the case 31 and the body 321. Subsequently, as the number of cycles of charging and discharging the battery cell 30 increases, the electrode assembly 32 gradually expands, and finally the restraining member 33 abuts between the circumferential surface of the body 321 and the case 31 to apply a certain restraining force to the body 321.

The direction of the binding force of the binding member 33 to the electrode assembly 32 may be a direction that counters the direction of the expansion force of the electrode assembly 32 itself, and may be disposed in the radial direction of the electrode assembly 32.

The minimum distance between the binding element 33 and the first end 321a may be the distance between the end of the binding element 33 close to the first end 321a and the first end 321a, and similarly, the minimum distance between the binding element 33 and the second end 321b may be the distance between the end of the binding element 33 close to the second end 321b and the second end 321b.

The body portion 321 has a middle section 321f at the first end 321a and the second end 321b, and the distance from the first end 321a to the middle section 321f is equal to the distance from the second end 321b to the middle section 321f.

The minimum distance between the first binding member 331 and the first end 321a is smaller than the minimum distance between the first binding member 331 and the second end 321b, and the first binding member 331 is disposed closer to the first end 321 a. Alternatively, the first binding member 331 may be disposed to cover the middle cross section 321f, may be disposed to be spaced apart from the middle cross section 321f, or one end of the first binding member 331 may be disposed to abut against the middle cross section 321f.

As the number of cycles of charge and discharge of the electrode assembly 32 increases, the amount of expansion of the anode piece of the electrode assembly 32 gradually increases, and the amount of expansion of the electrode assembly 32 increases in the area closer to the middle section 321f, and the internal stress of the electrode assembly 32 itself increases in the area closer to the middle section 321f if the tie 33 is not provided. In addition, as the electrode assembly 32 is gradually expanded, the binding force of the first binder 331 to the electrode assembly 32 is gradually increased. Since the minimum distance between the first binder 331 and the first end 321a is smaller than the minimum distance between the first binder 331 and the second end 321b, that is, the first binder 331 is asymmetrically arranged with respect to the middle section 321f in the axial direction X of the main body 321, the binding force distribution of the first binder 331 to the electrode assembly 32 is deviated from the middle section 321f, that is, the internal stress of the electrode assembly 32 is deviated from the middle section 321f and the area near the first end 321a is increased, so that the difference of the internal stress of at least a partial area of the electrode assembly 32 corresponding to the first binder 331 and the area near the middle section 321f of the first binder 331 can be balanced, so that the internal stresses of the electrode assemblies 32 corresponding to the two areas are as consistent as possible, and consistency of charging and discharging performance of the electrode assembly 32 is further provided.

Alternatively, the binding force of the first binding member 331 to the electrode assembly 32 may be equal or may be distributed in a curve along the axial direction X of the main body portion 321. Illustratively, from the middle section 321f to the axial direction X of the first end 321a, the binding force of the first binding member 331 on the electrode assembly 32 may be gradually increased to balance the internal stress difference of the electrode assembly 32 itself.

In the battery cell 30 provided in the embodiment of the present application, at least one binding piece 33 is disposed between the peripheral surface of the main body 321 and the housing 31, and the at least one binding piece 33 includes the first binding piece 331. By setting the minimum distance from the first binding piece 331 to the first end 321a to be smaller than the minimum distance from the first binding piece 331 to the second end 321b, the binding force distribution of the first binding piece 331 to the electrode assembly 32 deviates from the middle section 321f along with the increase of the number of times of cyclic charge and discharge of the electrode assembly 32, so that the internal stress of the region of the electrode assembly 32 deviating from the middle section 321f is enhanced, the internal stress difference of the electrode assembly 32 can be balanced, the internal stress distribution of the electrode assembly 32 is consistent as much as possible, the stability and the consistency of the charge and discharge performance of the electrode assembly 32 are improved, and the cycle life of the battery cell 30 is further prolonged.

Alternatively, the first tether 331 may be disposed in any area between the first end 321a and the middle cross-section 321f, or the first tether 331 may be partially disposed on a side of the middle cross-section 321f close to the second end 321b, which may be specifically selected as needed, and is not limited herein.

In some embodiments, the peripheral side of the electrode assembly 32 has a first attachment region 32a, and the first tether 331 is attached to at least a partial region of the first attachment region 32 a. The first attachment region 32a starts at the first end 321a and extends along the axial direction X, and the dimension of the first attachment region 32a along the axial direction X is less than 1/3 of the dimension of the main body portion 321 along the axial direction X.

Alternatively, the first tether 331 may be attached to the entire area of the first attachment region 32a or a partial area of the first attachment region 32a in the axial direction X of the electrode assembly 32.

Alternatively, the first binding piece 331 is attached to the first attachment area 32a, the first binding piece 331 may be integrally connected to the main body portion 321 of the first attachment area 32a by bonding or the like, and the first binding piece 331 may be provided to abut only against the main body portion 321 of the first attachment area, as long as the first binding piece 331 can generate a binding force on the main body portion 321.

It can be understood that, from the middle section 321f of the main body portion 321, the closer to the first end 321a, the smaller the expansion deformation of the electrode assembly 32, the greater the difference between the expansion deformation of the main body portion 321 closer to the first end 321a and the expansion deformation of the main body portion 321 closer to the middle section 321f, and therefore, the first restraining piece 331 is disposed at the first attachment area 32a, so that the difference between the internal stress of the electrode assembly 32 at the area of the first attachment area 32a, which is matched with the first restraining piece 331, and the internal stress of the electrode assembly 32 at the area close to the middle section 321f can be more favorably balanced, and the uniformity and stability of the charging and discharging performance of the electrode assembly 32 can be more favorably improved.

Fig. 6 shows a schematic cross-sectional structure view of a battery cell provided in an embodiment of the present application along an axial direction.

As shown in fig. 6, in some embodiments, the electrode assembly 32 includes a first pole piece 3211, the first pole piece 3211 includes a first active material layer located in the main body portion 321, the first active material layer 32111 includes a base region 321c and a thinned region 321d, the thinned region 321d has a thickness smaller than that of the base region 321c, and the thinned region 321d is located on a side of the base region 321c close to the first end 321a in the axial direction X.

Optionally, the first pole piece 3211 may be a positive pole piece or a negative pole piece, and therefore, one of the positive pole piece and the negative pole piece may be provided to include the base region 321c and the thinning region 321d, or both of the positive pole piece and the negative pole piece may be provided to include the base region 321c and the thinning region 321d.

By reducing the thickness of the thinned region 321d, in the process of cold press molding the first pole piece 3211, the stress concentration at the edge of the thinned region 321d, which is far away from the base region 321c, i.e., the first end 321a of the main body portion 321, can be reduced, and the risk of fracture of the first pole piece 3211 is reduced.

Alternatively, the surface of the thinned region 321d may be a plane or an arc. The thicknesses of the first pole pieces 3211 at various positions in the thinning region 321d may be equal or unequal, and may be specifically selected according to requirements, which is not limited herein.

In some embodiments, the first tie-down 331 is offset from the thinned area 321d in the axial direction X.

The first binding member 331 is disposed to be offset from the thinned region 321d, i.e., the thinned region 321d is not provided with the first binding member 331, and is not overlapped with the first binding member 331. Since the thickness of the thinned region 321d of the first pole piece 3211 is smaller than that of the base region 321c, the gap between the first pole piece 3211 of the thinned region 321d is larger than that of the base region 321c, and the strength of the first pole piece 3211 of the thinned region 321d is lower than that of the first pole piece 3211 of the base region 321 c. The thinned region 321d is more easily deformed by an external force. Therefore, the first constraining member 331 is disposed to be offset from the thinned region 321d, so as to reduce the risk of damage to the thinned region 321d caused by large deformation of the first constraining member 331.

Optionally, the first constraining member 331 and the thinning-out region 321d may be disposed adjacent to each other, or disposed at an interval, and in an embodiment where the first constraining member 331 and the thinning-out region 321d are disposed at an interval, a distance between the first constraining member 331 and the thinning-out region 321d is not limited, and may be selected according to actual requirements.

In some embodiments, the first binding member 331 is spaced from the thinning-out portion 321d by 1mm to 2mm in the axial direction X. Specifically, the distance between the first binding member 331 and the thinning-out portion 321d may be 1mm, 1.5mm, 2mm, or the like.

It is understood that the first binding member 331 may be spaced apart from the thinned region 321d by a distance from an end of the first binding member 331 near the thinned region 321d to an end of the thinned region 321d near the first binding member 331.

The distance between the first constraining member 331 and the thinning region 321d is set to be 1mm to 2mm, so that the risk that the first constraining member 331 generates constraining force on the thinning region 321d can be further reduced, and the risk that the electrode assembly 32 corresponding to the thinning region 321d is largely deformed and damaged can be reduced.

Fig. 7 is a schematic diagram illustrating an explosion structure of another battery cell 30 according to an embodiment of the present disclosure.

As shown in fig. 7, in some embodiments, at least one of the tie downs 33 includes a second tie down 332, and a minimum distance between the second tie down 332 and the second end 321b is less than a minimum distance between the second tie down 332 and the first end 321 a.

Alternatively, the thickness, shape, or structure of the second tie 332 and the first tie 331 may be the same or different.

Alternatively, the second tie 332 and the first tie 331 may be symmetrically disposed with respect to the middle cross section 321f or asymmetrically disposed with respect to the middle cross section 321f along the axial direction X. The first binding member 331 is disposed closer to one end, the second binding member 332 is disposed closer to the second end 321b,

the minimum distance from the second constraining member 332 to the second end 321b is smaller than the minimum distance from the second constraining member 332 to the first end 321a, and the second constraining member 332 is disposed closer to the second end 321b along the axial direction X, so that the expansion amount of the electrode assembly 32 gradually increases as the number of cycles of charging and discharging the electrode assembly 32 increases, and the constraining force of the second constraining member 332 to the electrode assembly 32 gradually increases, and since the second constraining member 332 is disposed closer to the second end 321b, the distribution of the constraining force of the second constraining member 332 to the electrode assembly 32 deviates from the middle section 321f, and is closer to the second end 321b, i.e. the internal stress of the electrode assembly 32 deviates from the middle section 321f in the area close to the second end 321b is increased, so that the difference of the internal stress of at least a part of the electrode assembly 32 corresponding to the first constraining member 331 and the area close to the middle section 321f can be balanced, so that the internal stress of the electrode assembly 32 is as consistent as possible, and the consistency of the charging and discharging performance of the electrode assembly 32 can be further improved.

It is understood that the amount of the binding force of the binding member 33 to the electrode assembly 32 may be adjusted by changing the thickness of the binding member 33, etc. Therefore, the thicknesses and the like of the first and second straps 331 and 332 may be adjusted so that the internal stresses of the electrode assembly 32 after the internal stresses of the electrode assembly 32 are enhanced by the first and second straps 331 and 332 are as uniform as possible, and thus, the uniformity of the charging and discharging performance of the electrode assembly 32 may be further improved.

Optionally, the second constraining member 332 may be disposed in any area between the second end 321b and the middle section 321f, or the second constraining member 332 may be partially disposed on a side of the middle section 321f close to the first end 321a, which may be specifically selected according to actual needs, and is not limited herein.

In some embodiments, the peripheral side of the electrode assembly 32 has a second attachment region 32b, and a second tie down 332 is attached to at least a portion of the second attachment region 32 b. The second end 321b of the second attachment region 32b is a starting end and extends along the axial direction X, and a dimension of the second attachment region 32b along the axial direction X is less than 1/3 of a dimension of the main body portion 321 along the axial direction X.

Alternatively, the second tie-down 332 may be attached to the entire area of the second attachment area 32b, or may be attached to a partial area of the second attachment area 32b in the axial direction X.

Alternatively, the second binding member 332 may be integrally connected to the second attachment region 32b by bonding or the like, or the second binding member 332 may be merely abutted against the second attachment region 32b, as long as the second binding member 332 can generate a binding force on the main body portion 321.

It can be understood that, starting from the middle section 321f of the main body 321, the closer to the second end 321b, the smaller the expansion deformation of the electrode assembly 32, the greater the difference between the expansion deformation of the main body 321 near the second end 321b and the expansion deformation of the main body 321 near the middle section 321f, so that the second tie down 332 is disposed at the second attachment region 32b, which is more beneficial to balance the difference between the internal stress of the electrode assembly 32 at the region of the second attachment region 32b, where the second tie down 332 is engaged with, and the internal stress of the electrode assembly 32 at the region near the middle section 321f, and is further beneficial to improve the uniformity and stability of the charging and discharging performance of the electrode assembly 32.

In some embodiments, the second tie 332 is symmetrically disposed with the first tie 331 in the axial direction X about the mid-section 321f.

Thus, the first binding member 331 symmetrically arranges the binding force of the electrode assembly 32 about the middle section 321f, which is beneficial to further improve the uniformity of the stress distribution in the electrode assembly 32, and further improve the uniformity of the charging and discharging performance of the electrode assembly 32.

Fig. 8 is a schematic diagram illustrating an explosion structure of a battery cell 30 according to another embodiment of the present disclosure.

As shown in fig. 8, in some embodiments, at least one tie 33 includes a third tie 333, the third tie 333 covering the mid-section 321f.

Specifically, the restraining force of the first and third restraining pieces 331 and 333 on the electrode assembly 32 may be adjusted so that the restraining force of the first restraining piece 331 on the electrode assembly 32 is smaller than the restraining force of the third restraining piece 333 on the electrode assembly 32, so that the third restraining piece 333 has a certain fixing effect on the electrode assembly 32 while balancing the internal stress of the electrode assembly 32, and the stability of the electrode assembly 32 in the case 31 may be improved.

In the embodiment where the constraint member 33 includes the first constraint member 331, the second constraint member 332 and the third constraint member 333 at the same time, the three members may be arranged at intervals, and the three members may have appropriate thicknesses or materials according to the relative positions of the three members in the axial direction X of the electrode assembly 32, so that the stresses in the electrode assembly 32 are as consistent as possible after the three members exert constraint forces on the electrode assembly 32, thereby improving the consistency of the charging and discharging performance of the electrode assembly 32.

Fig. 9 is a schematic diagram illustrating an explosion structure of another battery cell 30 provided in an embodiment of the present application.

In other embodiments, as shown in fig. 9, a third tether 333 is attached to the area between the mid-section 321f and the first end 321a, and the third tether 333 is located on the side of the first tether 331 near the second end 321b.

Specifically, by arranging the first and third restraints 331 and 333 to have different thicknesses or materials, etc., so that the restraining force of the third restraint 333 to the electrode assembly 32 is smaller than the restraining force of the first restraint 331 to the electrode assembly 32, and the internal stress of the electrode assemblies 32 corresponding to the third restraint 333 is as uniform as possible, the consistency of the charging and discharging performance of the electrode assembly 32 can still be improved, and the structural stability of the electrode assembly 32 can be improved.

Alternatively, the first and third binding members 331 and 333 may be provided with different thicknesses, different materials, or different thicknesses and different materials, so as to have different binding forces on the electrode assembly 32.

In some embodiments, the thickness of the first tie 331 is greater than the thickness of the third tie 333.

It is understood that the larger the thickness of the binder 33, the more space between the case 31 and the electrode assembly 32 is occupied, and the greater the binding force of the binder 33 to the electrode assembly 32 as the electrode assembly 32 expands. Since the first binder 331 is disposed closer to the first end 321a than the third binder 333, and the third binder 333 is disposed closer to the middle section 321f than the first binder 331, the expansion amount and the internal stress of the electrode assembly 32 itself corresponding to the first binder 331 are smaller than those of the electrode assembly 32 itself corresponding to the third binder. Therefore, the thickness of the first constraining member 331 is greater than that of the third constraining member 333, which is more beneficial to improve the uniformity of the stress in the electrode assembly 32, and further improve the uniformity of the charging and discharging performance of the electrode assembly 32.

The first and third restraints 331 and 333 may be provided with appropriate thicknesses according to the positions of the electrode assemblies 32 corresponding thereto so that the internal stresses of the electrode assemblies 32 corresponding thereto are as uniform as possible.

Fig. 10 is a schematic diagram illustrating an explosion structure of another battery cell 30 according to an embodiment of the present disclosure.

As shown in fig. 10, in some embodiments, at least one tie down 33 includes a fourth tie down 334, the fourth tie down 334 being attached to the area between the mid-section 321f and the second end 321b, and the fourth tie down 334 being located on the side of the second tie down 332 proximate to the first end 321 a.

Specifically, the first binder 331, the second binder 332 and the fourth binder 334 may have different thicknesses, materials and other information, so that the first binder 331, the second binder 332 and the fourth binder 334 respectively have appropriate binding force on the electrode assembly 32, and the internal stress of the electrode assembly 32 corresponding to the first binder 331, the second binder 332 and the fourth binder 334 is as consistent as possible.

In embodiments where at least one of the restraints 33 includes both a first restraint 331, a second restraint 332, a third restraint 333, and a fourth restraint 334, the third restraint 333 and the fourth restraint 334 may be symmetrically disposed about the mid-section 321f or may be asymmetric.

In some embodiments, at least one tie 33 includes a third tie 333, and a fourth tie 334 is disposed symmetrically with the third tie 333 about the mid-section 321f.

Specifically, the third constraining member 333 and the fourth constraining member 334 may be arranged to have the same constraining force on the electrode assembly 32, and since the electrode assemblies 32 corresponding to the third constraining member 333 and the fourth constraining member 334 are symmetrically arranged about the middle section 321f, the internal stresses of the electrode assemblies 32 corresponding to the third constraining member 333 and the fourth constraining member 334 are substantially the same, so that the internal stresses of the electrode assemblies 32 corresponding to the third constraining member 333 and the fourth constraining member 334 are substantially the same, which is beneficial to further improving the uniformity of the charging and discharging performance of the electrode assemblies 32.

In the embodiment where the third and fourth binding pieces 333 and 334 are symmetrically disposed about the middle section 321f, the first and second binding pieces 331 and 332 may be symmetrically disposed about the middle section 321f or asymmetrically disposed about the middle section 321f. It can be understood that, by arranging the first and second tie downs 331 and 332 symmetrically with respect to the middle cross section 321f and the third and fourth tie downs 333 and 334 symmetrically with respect to the middle cross section 321f, the uniformity of the charging and discharging performance of the electrode assembly 32 can be improved.

Alternatively, the binder 33 may be an elastic member or a non-elastic member. The tie members 33 may be members having a predetermined shape and structure before assembly, or may be structural bodies having stable structures and properties formed after or during assembly of the battery cells 30.

In some embodiments, the tie down 33 is configured to expand upon absorbing the electrolyte.

Alternatively, in an embodiment where the tether 33 includes a first tether 331, a second tether 332, a third tether 333, and a fourth tether 334, any one or more of the first tether 331, the second tether 332, the third tether 333, and the fourth tether 334 may be configured to expand after absorbing electrolyte, while the other tethers 33 may take other structural forms.

During the assembly of the battery cell 30, the volume of the restraining member 33 is small before the restraining member expands in the presence of the electrolyte, so that the restraining member 33 is easily inserted into the case 31 together with the electrode assembly 32. After the electrolyte is filled into the battery cell 30, the binding member 33 expands to reach a predetermined thickness and volume, so that a certain binding force is formed on the electrode assembly 32 in the subsequent use process.

Therefore, by providing the binder 33 configured to expand after absorbing the electrolyte, it is possible to facilitate smooth proceeding of the packing operation of the binder 33 and the electrode assembly 32 during the assembly process while ensuring the binding action of the binder 33 on the electrode assembly 32.

In order to expand the binder 33 after absorbing the electrolyte, various materials of the binder 33 may be provided. In some embodiments, the material of the tether 33 comprises at least one of thermoplastic polyurethane, dextran gel, and hydroxyl terminated polybutadiene-polyurethane.

Optionally, the material of the tie 33 may include one of thermoplastic polyurethane, dextrangel and hydroxyl-terminated polybutadiene-polyurethane, and the material of the tie 33 may also include two or all of thermoplastic polyurethane, dextrangel and hydroxyl-terminated polybutadiene-polyurethane.

In the embodiment where the binding member 33 includes the first binding member 331, the second binding member 332, the third binding member 333 and the fourth binding member 334, different binding members 33 may be made of the same material or different materials, and may be selected as required.

It is understood that the expansion coefficients of the different materials are different, for example, the expansion coefficient of the thermoplastic polyurethane is 30 to 40, the expansion coefficient of the dextran gel is 1 to 4, and the expansion coefficient of the hydroxyl-terminated polybutadiene-polyurethane is 0.3 to 8. Therefore, the material of the binding member 33 includes at least one of thermoplastic polyurethane, sephadex and hydroxyl-terminated polybutadiene-polyurethane, and the ratio of the components in the material of the binding member 33 can be reasonably distributed, so that the binding member 33 has a proper thickness after swelling in the presence of the electrolyte, and the binding member 33 formed after swelling has a proper binding force on the electrode assembly 32.

Alternatively, the binder 33 may be disposed around one, less than one, or more than one circumference of the electrode assembly 32 in the circumferential direction of the electrode assembly 32, and may be selected as needed, without limitation.

Fig. 11 to fig. 14 respectively show a cross-sectional structural schematic view of a battery cell provided in different embodiments along a direction perpendicular to an axial direction.

As shown in fig. 11 to 13, in some embodiments, the tie 33 has a first free end 33a and a second free end 33b along the circumferential direction of the electrode assembly 32. Specifically, the binder 33 extends from a first free end 33a to a second free end 33b in the circumferential direction of the electrode assembly 32.

Optionally, the structural forms of the different binding members 33 of the same battery cell 30 may be the same or different, and may be selected according to specific requirements.

Alternatively, the first free end 33a and the second free end 33b may be disposed in an overlapping manner or in a spaced manner. When the first free end 33a and the second free end 33b are disposed to overlap, the restraining member 33 covers just one turn of the electrode assembly 32. When the first free end 33a and the second free end 33b are spaced apart from each other, the restraining member 33 covers the electrode assembly 32 less than one turn or more than one turn in the circumferential direction of the electrode assembly 32.

As shown in fig. 11, in some embodiments, the binder 33 includes an overlapping portion 33c disposed between the first free end 33a and the second free end 33b, and a central angle α of the overlapping portion 33c in a circumferential direction of the electrode assembly 32 satisfies: alpha is less than or equal to 30 degrees.

In the above embodiment, the binder 33 covers the electrode assembly 32 more than one turn in the circumferential direction of the electrode assembly 32.

Alternatively, the central angle α of the overlapping portion 33c may be 5 °, 10 °, 15 °, 20 °, 25 °, 30 °, or the like.

The binding member 33 is provided with an overlapping part 33c, and the central angle alpha of the overlapping part 33c satisfies the following conditions: alpha is less than or equal to 30 deg., it is advantageous to secure the binding force of the binding member 33 to the electrode assembly 32 and to facilitate the installation of the binding member 33.

In other embodiments, as shown in fig. 12, the first free end 33a and the second free end 33b are spaced apart, and the main body 321 has an exposed area 321e, and the exposed area 321e is located between the first free end 33a and the second free end 33b and exposed outside the binding member 33. The central angle β of the exposed region 321e satisfies, along the circumferential direction of the electrode assembly 32, β ≦ 180 °.

Alternatively, the central angle β of the exposed area 321e may be 30 °, 45 °, 60 °, 90 °, 120 °, 150 °, 180 °, or the like.

The electrode assembly 32 is provided with the exposed area 321e between the first free end 33a and the second free end 33b, so that the restraint member 33 can provide a certain restraining force for the electrode assembly 32, and meanwhile, the electrolyte can enter the electrode assembly 32 through the exposed area 321e, and the wettability of the electrolyte to the electrode assembly 32 is improved. In addition, the exposed region 321e between the first free end 33a and the second free end 33b may provide a space for expansion of the electrode assembly 32, reducing the risk of damage to the electrode assembly 32 due to expansion deformation.

In still other embodiments, as shown in fig. 13, the first free end 33a and the second free end 33b coincide. The binder 33 is disposed right around one circumference of the electrode assembly 32 without the first and second free ends 33a and 33b overlapping. This is advantageous in improving the flatness of the surface of the binder 33 to improve the structural stability of the battery cell 30.

As shown in fig. 14, in some embodiments, the tie 33 includes a plurality of first portions 33d, and the plurality of first portions 33d are spaced apart in the circumferential direction of the electrode assembly 32.

Alternatively, the number of the first portions 33d of one binder 33 may be two, three or more. The center angles of the different first portions 33d may be the same or different. The spacing distances of the first portions 33d may be the same or different, and may be set according to actual needs.

The constraint piece 33 is provided with the first parts 33d, and the first parts 33d are arranged at intervals, so that the constraint force of the constraint piece 33 on the electrode assembly 32 is ensured, the possibility of shaking of the electrode assembly 32 is reduced, and meanwhile, the gaps of the first parts 33d along the circumferential direction of the electrode assembly 32 can be used as electrolyte circulation channels, and the mobility of electrolyte is improved. In addition, the gap between the first portions 33d may reserve a space for expansion of the electrode assembly 32, further reducing the risk of damage to the electrode assembly 32 due to expansion deformation.

In some embodiments, the electrode assembly 32 includes a first pole piece 3211, the first pole piece 3211 wound in a plurality of turns. In the circumferential direction of the electrode assembly 32, the binder 33 is offset from the tail end 3211a of the outermost first pole piece 3211.

Optionally, the first pole piece 3211 may be a positive pole piece or a negative pole piece. The first pole piece 3211 may be wound in multiple turns along a winding direction, the winding direction is perpendicular to the axial direction X, and a tail end 3211a of the first pole piece 3211 is an edge of the first pole piece 3211 along the winding direction.

The binding member 33 is disposed in a staggered manner with respect to the tail end 3211a of the first pole piece 3211 at the outermost ring, and the binding member 33 abuts against the inside of the tail end 3211a of the first pole piece 3211 along the circumferential direction of the electrode assembly 32.

Alternatively, the tail end 3211a of the first pole piece 3211 may be disposed in the exposed region 321e of the electrode assembly 32, or the tail end 3211a of the first pole piece 3211 may be disposed in a region between two adjacent first portions 33d, so as to achieve the staggered arrangement of the first portions 33e and the tail end 3211 a.

Thus, the binding member 33 does not generate a large acting force on the tail end 3211a of the first pole piece 3211, which is beneficial to reducing the risk of stress concentration of the electrode assembly 32 at the tail end 3211a of the first pole piece 3211, and further reducing the risk of damage to the electrode assembly 32 due to deformation.

In some embodiments, the battery cell 30 includes a case 31, an electrode assembly 32, and a binder 33, and the binder 33 includes a first binder 331, a second binder 332, a third binder 333, and a fourth binder 334 which are spaced apart from each other. The electrode assembly 32 includes a body portion 321, the body portion 321 having a first end 321a and a second end 321b oppositely disposed along an axial direction X of the electrode assembly 32, and a middle section 321f between the first end 321a and the second end 321b. The binder 33 is provided between the peripheral surface of the body 321 and the case 31, and the binder 33 is arranged to expand when exposed to the electrolyte. The first and second tethers 331 and 332 are symmetrically disposed with respect to the middle cross section 321f, the third and fourth middle cross sections 321f and 321f are oppositely disposed, and the first and third tethers 331 and 333 are located on a side of the middle cross section 321f near the first end 321a, the second and fourth tethers 332 and 334 are located on a side of the middle cross section 321f near the second end 321b, and the first tethers 331 are located on a side of the third tethers 333 near the first end 321a, the first tethers 331 having a thickness greater than the second tethers 332. The main body 321 includes a first pole piece 3211, the first pole piece 3211 is wound in multiple turns, and the tie bar 33 and the tail end 3211a of the outermost first pole piece 3211 are disposed in a staggered manner in the circumferential direction of the electrode assembly 32. The first substrate includes a first active material layer 32111, the first active material layer 32111 includes a base region 321c and a thinning-out region 321d, the thickness of the thinning-out region 321d is smaller than that of the base region 321c, and the thinning-out region 321d is located on the side of the base region 321c close to the first end 321a and the side of the base region 321c close to the second end 321b in the axial direction X. The binding piece 33 and the thinning area 321d are arranged in a staggered mode, and the minimum distance from the binding piece 33 is 1 mm-2 mm.

The battery 10 provided according to the embodiment of the present application includes the battery cell 30 provided in any one of the above embodiments.

The battery 10 provided in the embodiment of the present application has the same technical effect due to the adoption of the battery cell 30 provided in any one of the above embodiments, and details are not described herein.

The power utilization device provided according to the embodiment of the present application includes the battery 10 provided in the above embodiment, and the battery 10 is used for providing electric energy.

The power consumption device provided by the embodiment of the present application has the same technical effect due to the battery 10 provided by the above embodiment, and details are not described herein again.

It should be noted that, in the present application, the embodiments and features of the embodiments may be combined with each other without conflict.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may be modified or some technical features may be equivalently replaced, but the modifications or the replacements do not cause the essence of the corresponding technical solutions to depart from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims (20)

1. A battery cell, comprising:

a housing;

an electrode assembly disposed within the case, the electrode assembly including a main body portion having first and second ends oppositely disposed in an axial direction of the electrode assembly;

at least one binding piece arranged between the peripheral side surface of the main body part and the shell,

wherein the at least one tie comprises a first tie having a minimum spacing from the first end that is less than a minimum spacing of the first tie from the second end.

2. The battery cell of claim 1, wherein the electrode assembly peripheral side has a first attachment region, the first binder being attached to at least a portion of the first attachment region; the first attachment region starts at the first end and extends in the axial direction, and the dimension of the first attachment region in the axial direction is smaller than 1/3 of the dimension of the main body portion in the axial direction.

3. The battery cell according to claim 1, wherein the electrode assembly includes a first pole piece including a first active material layer located in the main body portion, the first active material layer includes a base region and a thinned region, the thinned region having a thickness smaller than that of the base region, the thinned region being located on a side of the base region near the first end in the axial direction;

in the axial direction, the first binding piece and the thinning area are arranged in a staggered mode.

4. The battery cell as recited in claim 3 wherein the first restraint is spaced from the thinned region by 1mm to 2mm in the axial direction.

5. The battery cell of any of claims 1-4, wherein the at least one tie down comprises a second tie down having a minimum spacing from the second end that is less than a minimum spacing from the first end.

6. The battery cell according to claim 5, wherein the electrode assembly has a peripheral side surface having a second attachment region, the second tie down being attached to at least a partial region of the second attachment region; the second attachment region starts from the second end and extends along the axial direction, and the size of the second attachment region along the axial direction is smaller than 1/3 of the size of the main body part along the axial direction.

7. The battery cell as recited in claim 5 wherein the main body portion has a mid-section between the first and second ends, the second tie being symmetrically disposed with the first tie about the mid-section in the axial direction.

8. The battery cell of claim 1, wherein the at least one tie down includes a third tie down, the body portion having a mid-section between the first end and the second end, the third tie down covering the mid-section.

9. The battery cell of claim 1, wherein the at least one tie includes a third tie, the body portion has a mid-cross section between the first end and the second end, the third tie is attached to an area between the mid-cross section and the first end, and the third tie is located on a side of the first tie proximate the second end.

10. The battery cell as recited in claim 8 or 9 wherein the thickness of the first tie down is greater than the thickness of the third tie down.

11. The battery cell of claim 5, wherein the body portion has a mid-section at the first end and the second end;

the at least one tie down includes a fourth tie down attached to an area between the mid-section and the second end, and the fourth tie down is located on a side of the second tie down proximate the first end.

12. The battery cell of claim 11, wherein the at least one tie includes a third tie, the fourth tie and the third tie being symmetrically disposed about the mid-section.

13. The battery cell as recited in claim 1 wherein the tie down is configured to swell upon absorbing electrolyte.

14. The battery cell of claim 13, wherein the material of the tie comprises thermoplastic polyurethane, sephadex, or hydroxyl terminated polybutadiene-polyurethane.

15. The battery cell as recited in claim 1 wherein the tie has a first free end and a second free end along a circumferential direction of the electrode assembly;

the binder includes an overlapping portion disposed between the first free end and the second free end, a central angle α of the overlapping portion in a circumferential direction of the electrode assembly satisfies: alpha is less than or equal to 30 degrees.

16. The battery cell as recited in claim 1 wherein the tie member has a first free end and a second free end spaced apart along a circumferential direction of the electrode assembly;

the main body part is provided with an exposed area which is positioned between the first free end and the second free end and exposed outside the binding piece; the central angle beta of the exposed area along the circumferential direction of the electrode assembly satisfies that beta is less than or equal to 180 degrees.

17. The battery cell of claim 1, wherein the tie includes a plurality of first portions that are spaced apart along a circumference of the electrode assembly.

18. The battery cell according to claim 16 or 17, wherein the electrode assembly comprises a first pole piece wound in a plurality of turns;

in the circumferential direction of the electrode assembly, the binding piece and the tail end of the first pole piece at the outermost ring are arranged in a staggered mode.

19. A battery comprising a cell according to any one of claims 1 to 18.

20. An electrical device comprising a battery as claimed in claim 19 for providing electrical energy.

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