CN112803081B

CN112803081B - Battery monomer, preparation method thereof, battery and power utilization device

Info

Publication number: CN112803081B
Application number: CN202110400340.3A
Authority: CN
Inventors: 杨彦超; 唐代春; 上官会会; 杨晴雅
Original assignee: Jiangsu Contemporary Amperex Technology Ltd
Current assignee: Jiangsu Contemporary Amperex Technology Ltd
Priority date: 2021-04-14
Filing date: 2021-04-14
Publication date: 2021-08-06
Anticipated expiration: 2041-04-14
Also published as: CN112803081A

Abstract

The embodiment of the application relates to the technical field of batteries, in particular to a battery monomer, a preparation method of the battery monomer, a battery and an electric device. The battery monomer comprises an electrode assembly and a liquid storage component, wherein the electrode assembly comprises a first pole piece, an isolation film and a second pole piece, and the isolation film is used for isolating the first pole piece from the second pole piece; a reservoir member is attached to the electrode assembly, the reservoir member having a porosity greater than a porosity of the separator. The battery monomer that this application embodiment provided has improved electrode subassembly's guarantor's liquid ability through increase the stock solution component at electrode subassembly, has increased the infiltration degree of electrolyte to electrode subassembly, has prolonged the free life of battery, has improved the free safety in utilization of battery.

Description

Battery monomer, preparation method thereof, battery and power utilization device

Technical Field

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

Background

The single battery comprises an electrode assembly and electrolyte, and the charge and discharge performance of the single battery is greatly influenced by the infiltration degree of the electrolyte on the electrode assembly. When the single battery is in use, if electrolyte is lacked, the lithium precipitation phenomenon easily occurs on the electrode assembly, so that the capacity of the single battery is attenuated, the crystallized lithium dendrite branches grow, and the isolating membrane between the positive pole piece and the negative pole piece can be punctured, so that the short circuit of the single battery is caused, the thermal runaway of the single battery is caused, and the service life and the use safety of the single battery are reduced.

Disclosure of Invention

In view of the above problems, embodiments of the present application provide a battery cell, a method for manufacturing the battery cell, a battery, and an electric device, in which a liquid storage member is attached to an electrode assembly, so that the liquid retention capability of the electrode assembly is improved, the infiltration degree of an electrolyte to the electrode assembly is increased, the service life of the battery cell is prolonged, and the use safety of the battery cell is improved.

According to an aspect of an embodiment of the present application, there is provided a battery cell, including an electrode assembly, the electrode assembly including a first pole piece, a separation film and a second pole piece, the separation film being used for separating the first pole piece and the second pole piece; the isolation film comprises a first isolation film and a second isolation film, and the first pole piece, the first isolation film, the second pole piece and the second isolation film are arranged in a stacked mode and wound to form a winding structure; the ending section of the second isolating membrane is positioned on the outer side of the ending section of the first isolating membrane; the electrode assembly further comprises an adhesive tape which is attached to the outer surface of the electrode assembly to fix the ending section of the second separation film; and a reservoir member attached to the electrode assembly, the reservoir member having a porosity greater than a porosity of the separator.

By adopting the scheme, the electrolyte storage component has stronger electrolyte storage capacity than the isolating membrane, and is attached to the electrode assembly, so that the infiltration degree of the electrolyte to the electrode assembly is improved, the service life of the battery monomer is prolonged, and the use safety of the battery monomer is improved. The ending section of the second isolating film is positioned on the outer side of the whole electrode assembly, and the ending section of the second isolating film is fixed by the adhesive tape, so that the electrode assembly formed by winding the first pole piece, the first isolating film, the second pole piece and the second isolating film is not easy to scatter and has a stable structure.

In some embodiments, the porosity of the reservoir member is from 32% to 90%.

By adopting the scheme, when the porosity is in the interval, the liquid storage component is easy to process and manufacture, and the liquid retaining capability of the electrode assembly using the liquid storage component with the porosity is obviously superior to that of the electrode assembly without the liquid storage component.

In some embodiments, the reservoir member is the same polarity as the electrolyte.

By adopting the above scheme, according to the similarity and intermiscibility principle, the liquid storage component can absorb and store the electrolyte more easily under the condition that the polarities of the liquid storage component and the electrolyte are the same, namely, the liquid storage component and the electrolyte are both hydrophilic substances or both lipophilic substances, so that the liquid retention capacity of the electrode assembly is further increased.

In some embodiments, the reservoir member includes pores extending in a height direction of the battery cell.

By adopting the scheme, the electrolyte can be absorbed from the bottom of the electrode assembly by the liquid storage component, the holding capacity of the electrolyte is increased, and the infiltration capacity of the electrolyte on the electrode assembly is improved.

In some embodiments, the porosity of the reservoir member is greater than the porosity of the tape.

Through adopting above-mentioned scheme, the electrolyte that permeates to the stock solution component from the sticky tape can be stored in the stock solution component as far as to the reinforcing is to the ability of keeping of electrolyte.

In some embodiments, the reservoir member is located on a side of the tape proximate to the winding axis of the electrode assembly.

Through adopting above-mentioned scheme, the stock solution component is close to the pole piece more, and the electrolyte that the stock solution component was stored can reach the pole piece sooner, guarantees electrode subassembly's charge-discharge performance.

In some embodiments, the liquid storage member is positioned between the outermost pole piece and the tape.

By adopting the scheme, the adhesive tape can be used for fixing the ending section of the second isolation film and also can be used for fixing the liquid storage component to prevent the liquid storage component from falling off; and the arrangement of the liquid storage component can not obstruct the transmission of lithium ions between the first pole piece and the second pole piece, and the stable operation of the charging and discharging process of the single battery is ensured.

In some embodiments, the reservoir component is located between the trailing section of the first separator film and the trailing section of the second separator film.

By adopting the scheme, the liquid storage component is closer to the periphery of the electrode assembly, so that the electrolyte penetrating through the adhesive tape is better absorbed; in addition, the liquid storage component is not directly contacted with the first pole piece or the second pole piece, so that the risk that active substances coated on the surfaces of the pole pieces fall off due to friction of the liquid storage component is reduced, and the stability of the electrical performance of the battery monomer is further ensured.

In some embodiments, the electrode assembly includes a flat region and two bent regions connected to both ends of the flat region, respectively; the two ends of the liquid storage component in the winding direction of the electrode component are respectively positioned in the two bending areas.

By adopting the scheme, the liquid storage component passes through the straight area at least once in the winding process, so that the area of the liquid storage component is larger, more electrolyte is stored, and the infiltration capacity of the electrolyte on the electrode assembly is improved.

In some embodiments, a projection of the reservoir member covers a projection of the flat region in a thickness direction of the electrode assembly.

Through adopting above-mentioned scheme, on the one hand, the area of stock solution component is great, and consequently, the total holding capacity of electrolyte in the stock solution component is great, has improved the infiltration ability of electrolyte to electrode subassembly. On the other hand, the end part of the liquid storage component cannot fall on the flat area of the electrode assembly, so that unevenness of the surface of the flat area cannot be caused, indentation and crumpling of the flat area caused by stress concentration when the electrode assembly is subjected to hot pressing or expansion are avoided, and the risk of short circuit or damage of the electrode assembly due to the fact that the electrode assembly is short-circuited or damaged is reduced.

According to a second aspect of the embodiments of the present application, there is provided a battery including the above battery cell.

By adopting the scheme, the battery has stable charge and discharge performance, long service life and high use safety.

According to a third aspect of the embodiments of the present application, there is provided an electric device including the above battery cell.

By adopting the scheme, the service life of the battery monomer of the electric device is long, and the service safety of the device is high.

According to a fourth aspect of the embodiments of the present application, there is provided a method for preparing a battery cell, for preparing the battery cell of the above embodiments, including the steps of:

providing a first pole piece, an isolation film and a second pole piece, wherein the isolation film comprises a first isolation film and a second isolation film;

providing an adhesive tape;

providing a liquid storage component, wherein the porosity of the liquid storage component is greater than that of the isolation membrane;

providing a housing having a receiving cavity;

assembling a first pole piece, an isolation film, a second pole piece and a liquid storage component, wherein the first pole piece, the first isolation film, the second pole piece and the second isolation film are stacked and form a winding structure to obtain an electrode assembly, and the ending section of the second isolation film is positioned on the outer side of the ending section of the first isolation film; and attaching the reservoir member to the electrode assembly;

attaching an adhesive tape to an outer surface of the electrode assembly to fix the finishing section of the second separator;

the electrode assembly is received in the receiving cavity.

By adopting the scheme, in the prepared single battery, the liquid absorbing capacity and the liquid retaining capacity of the liquid storage component are better, so that the electrolyte can better infiltrate the electrode assembly, the service life of the single battery is prolonged, and the use safety of the single battery is improved.

The foregoing description is only an overview of the technical solutions of the embodiments of the present application, and the embodiments of the present application can be implemented according to the content of the description in order to make the technical means of the embodiments of the present application more clearly understood, and the detailed description of the present application is provided below in order to make the foregoing and other objects, features, and advantages of the embodiments of the present application more clearly understandable.

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 description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.

Fig. 1 is a schematic structural diagram of an electric device according to an embodiment of the present application.

Fig. 2 is a schematic structural diagram of a battery according to an embodiment of the present application.

Fig. 3 is a schematic structural diagram of a battery module according to an embodiment of the present disclosure.

Fig. 4 is a schematic structural diagram of a battery cell according to an embodiment of the present application.

Figure 5 is a schematic cross-sectional view of an electrode assembly in an embodiment of the present application.

Figure 6 is a schematic cross-sectional view of an electrode assembly in another embodiment of the present application.

Fig. 7 is a schematic structural view of an electrode assembly in an embodiment of the present application.

Fig. 8 is a structural view of the electrode assembly of fig. 7, taken along the height direction.

Fig. 9 is a schematic view of the structure of an electrode assembly in another embodiment of the present application.

Fig. 10 is a schematic view of the electrode assembly of fig. 9, taken in a height direction.

Fig. 11 is a schematic view of the structure of an electrode assembly in a further embodiment of the present application.

Fig. 12 is a schematic view of the electrode assembly of fig. 11, taken along the height direction.

Fig. 13 is a schematic view of the structure of an electrode assembly in a further embodiment of the present application.

Fig. 14 is a schematic view of the electrode assembly of fig. 13, taken in a height direction.

Fig. 15 is a flow chart illustrating the preparation of a battery cell according to an embodiment of the present disclosure.

Fig. 16 is a flow chart illustrating the preparation of a battery cell according to another embodiment of the present application.

Description of reference numerals: 2. an automobile; 200. a battery; 210. a controller; 220. a motor; 300. a battery module; 201. a first case; 202. a second case; 400. a battery cell; 20. a housing; 40. an electrode assembly; 401. a flat area; 402. a bending zone; 41. a positive electrode tab; 42. a negative electrode tab; 43. a first pole piece; 44. a second pole piece; 45. a first barrier film; 451. a tail section of the first separator; 46. a second barrier film; 461. a finishing section of the second barrier film; 47. an isolation film; 5. a liquid storage member; 6. an adhesive tape; 1. an end cap assembly; 11. an end cap; 12. an electrode terminal; 13. a liquid injection hole; 30. a connecting member.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection 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 in the description of the application 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 and claims of this application and the description of the drawings are intended to cover, but not to exclude, other elements. The word "a" or "an" does not exclude a plurality.

Reference herein 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 application. The appearances of the phrase "an embodiment" 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.

The term "and/or" herein is merely an association describing an associated object, meaning that three relationships may exist, e.g., a and/or B, may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.

The following description is given with the directional terms as they are shown in the drawings, and is not intended to limit the specific structure of the battery cell, the battery or the power device of the present application. For example, in the description of the present application, the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in an orientation or positional relationship indicated based on the orientation or positional relationship shown in the drawings for the convenience of description and simplicity of description only, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be considered as limiting the present application.

Further, expressions of directions indicated for explaining the operation and configuration of each member of the battery cell, the battery or the electric device of the present embodiment, such as the X direction, the Y direction and the Z direction, are not absolute but relative, and although these indications are appropriate when each member of the battery pack is in the position shown in the drawings, when the position is changed, the directions should be interpreted differently to correspond to the change.

Furthermore, the terms "first," "second," and the like in the description and claims of the present application or in the above-described drawings are used for distinguishing between different objects and not necessarily for describing a particular sequential order, and may explicitly or implicitly include one or more of the features.

In the description of the present application, unless otherwise specified, "plurality" means two or more (including two), and similarly, "plural groups" means two or more (including two).

In the description of the present application, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., "connected" or "connected" of a mechanical structure may refer to a physical connection, e.g., a physical connection may be a fixed connection, e.g., a fixed connection by a fastener, such as a screw, bolt, or other fastener; the physical connection can also be a detachable connection, such as a mutual clamping or clamping connection; the physical connection may also be an integral connection, for example, a connection made by welding, gluing or integrally forming the connection. "connected" or "connected" of circuit structures may mean not only physically connected but also electrically connected or signal-connected, for example, directly connected, i.e., physically connected, or indirectly connected through at least one intervening component, as long as the circuits are in communication, or communication between the interiors of two components; signal connection may refer to signal connection through a medium, such as radio waves, in addition to signal connection through circuitry. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art.

In the present application, the battery cell may include a lithium ion secondary battery, a lithium ion primary battery, a lithium sulfur battery, a sodium lithium ion battery, a sodium ion battery, a magnesium ion battery, or the like, which is not limited in the embodiments of the present application. 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 cylindrical battery monomer, the square battery monomer and the soft package battery monomer are not limited in the embodiment of the application.

The battery monomer comprises a shell, an electrode assembly and electrolyte, wherein the electrode assembly consists of a positive pole piece, a negative pole piece and an isolating membrane. 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 includes anodal mass flow body and anodal active substance layer, and anodal active substance layer coats in anodal mass flow body's surface, and the anodal mass flow body protrusion in the anodal mass flow body that has coated anodal active substance layer of uncoated anodal active substance layer, and the anodal mass flow body that does not coat anodal active substance layer is as anodal utmost point ear. Taking a lithium ion battery as an example, the material of the positive electrode current collector may be aluminum, and the positive electrode active material may be lithium cobaltate, lithium iron phosphate, ternary lithium, lithium manganate, or the like. The negative pole piece includes negative pole mass flow body and negative pole active substance layer, and the negative pole active substance layer coats in the surface of negative pole mass flow body, and the negative pole mass flow body protrusion in the negative pole mass flow body of coating the negative pole active substance layer not coating the negative pole active substance layer, and the negative pole mass flow body of not coating the negative pole active substance layer is as negative pole utmost point ear. The material of the negative electrode current collector may be copper, and the negative electrode active material may be carbon, silicon, or the like. In order to ensure that the fuse is not fused when a large current is passed, the number of the positive electrode tabs is multiple and the positive electrode tabs are stacked together, and the number of the negative electrode tabs is multiple and the negative electrode tabs are stacked together. The material of the isolation film can be PP or PE, etc. 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.

The shell comprises a shell body and an end cover assembly, wherein the shell body is provided with an accommodating cavity, the shell body is provided with an opening, namely the accommodating cavity is communicated with the outside of the shell body without a side wall in one direction of the shell body, after the electrode assembly is arranged in the accommodating cavity from the opening, the opening is closed by the end cover assembly, electrolyte is injected into the accommodating cavity through an electrolyte injection hole in the end cover assembly, and finally the electrolyte injection hole is sealed to prevent the circulation of gaseous, liquid or solid substances between the inside and the outside of the shell body.

When the electrolyte is actually filled, considering that the electrode assembly expands along with the charging and discharging, the pressure inside the accommodating cavity changes and the safety of the battery cell, the accommodating cavity is usually not completely filled with the electrolyte, which causes the electrode assembly to be incapable of being completely immersed in the electrolyte, and the immersion degree of the electrolyte on the electrode assembly greatly affects the charging and discharging performance of the battery cell.

The contact area between the surface of the electrode assembly and the electrolyte and the liquid retention capacity of the isolating membrane are key factors for restricting the infiltration of the electrolyte.

The inventor researches and discovers that the problem of insufficient electrolyte infiltration of the electrode assembly is easy to occur because the liquid retention capacity of the separation film is poor and the electrolyte capable of being stored is less.

In view of this, in the single battery in the application, the liquid storage component is attached to the electrode assembly, and the porosity of the liquid storage component is greater than that of the isolation film, so that the retention amount of the electrode assembly on the electrolyte is increased under the condition that the normal use of the electrode assembly is not affected, the infiltration degree of the electrolyte on the electrode assembly is improved, the service life of the single battery is prolonged, and the use safety of the single battery is improved.

The battery in the embodiment of the present application may be applied to various electric devices using the battery, such as a mobile phone, a portable device, a notebook computer, a battery car, an electric toy, an electric tool, an electric vehicle, a ship, a spacecraft, and the like, for example, but not limited to, a spacecraft including an airplane, a rocket, a space shuttle, and a spacecraft.

As shown in fig. 1, for a structural schematic diagram of an automobile 2 provided in an embodiment of the present application, the automobile 2 may be a fuel automobile, a gas automobile, or a new energy automobile, and the new energy automobile may be a pure electric automobile, a hybrid electric automobile, or an extended range automobile, etc. The automobile 2 includes a battery 200, a controller 210, and a motor 220. The battery 200 is used to supply power to the controller 210 and the motor 220 as an operation power source and a driving power source of the automobile, for example, the battery 200 is used for a power demand for operation in starting, navigation and running of the automobile 2. For example, the battery 200 supplies power to the controller 210, the controller 210 controls the battery 200 to supply power to the motor 220, and the motor 220 receives and uses the power of the battery 200 as a driving power source of the automobile 2, instead of or in part of fuel or natural gas, to provide driving power for the automobile 2.

As shown in fig. 2, in order to achieve higher power of the battery 200 to meet the use requirement, in an embodiment, the battery 200 may include a plurality of battery modules 300 electrically connected to each other.

For example, the battery 200 includes a case including a first case 201 and a second case 202, wherein the first case 201 and the second case 202 are fastened to each other, and the battery module 300 is disposed in a space defined by the first case 201 and the second case 202. It is understood that there may be one or more of the battery modules 300.

In some embodiments, the first case 201 and the second case 202 may be made of aluminum, aluminum alloy, or other metal materials.

In some embodiments, the first case 201 and the second case 202 are hermetically connected.

As shown in fig. 3, the battery module 300 may include one or more battery cells 400, and when the battery module 300 includes a plurality of battery cells 400, the plurality of battery cells 400 may be electrically connected in series, in parallel, or in series-parallel to achieve a larger current or voltage, wherein the series-parallel refers to a combination of series and parallel. In addition, the plurality of battery cells 400 may be arranged according to a predetermined rule, as shown in fig. 3, the battery cells 400 may be placed vertically, the height direction of the battery cells 400 coincides with the Z direction in the drawing, the thickness direction of the battery cells coincides with the Y direction in the drawing, and the plurality of battery cells 400 are arranged side by side along the Y direction in the drawing, wherein the Y direction is perpendicular to the Z direction.

As shown in fig. 4, a schematic structural diagram of a battery cell 400 provided for an embodiment of the present application is a battery cell 400, where the battery cell 400 includes a housing and one or more electrode assemblies 40 placed in the housing, the housing includes an end cap assembly 1 and a case 20, the housing is a hollow cavity, for example, the case 20 has a receiving cavity, and one face of the case 20 has an opening, that is, the plane does not have a housing wall so that the inside and the outside of the case 20 communicate with each other, so that the electrode assemblies 40 can be received in the receiving cavity of the case 20, and the end cap assembly 1 is combined with the case 20 at the opening of the case 20 to form the hollow cavity.

The case 20 is determined according to the shape of the one or more electrode assemblies 40 after being combined, and for example, the case 20 may be a hollow rectangular parallelepiped or a hollow cube or a hollow cylinder. For example, when the housing 20 is a hollow rectangular parallelepiped or cube, one of the planes of the housing 20 is an open plane, i.e., the plane has no housing wall so that the housing 20 communicates inside and outside; when the housing 20 is a hollow cylinder, at least one circular side of the housing 20 is an open surface, i.e., the circular side has no housing wall so that the housing 20 communicates inside and outside. The housing 20 may be made of a metallic material or plastic, and in some embodiments, the housing 20 is made of aluminum or an aluminum alloy.

As shown in fig. 4, the end cap assembly 1 includes an end cap 11 and two electrode terminals 12, the two electrode terminals 12 are a positive electrode terminal and a negative electrode terminal, respectively, one connecting member 30 is disposed corresponding to each electrode terminal 12, and the connecting member 30 is used to electrically connect the electrode assembly 40 and the electrode terminals 12.

Fig. 4 only illustrates the battery cell 400 having one end cap assembly 1, and it is understood that the battery cell 400 may also include two end cap assemblies 1, the two end cap assemblies 1 are respectively disposed at two ends of the housing 20, and each end cap assembly 1 is provided with one electrode terminal 12.

The end cap assembly 1 is further provided with a liquid injection hole 13 for injecting electrolyte into the accommodating cavity, and after the injection is completed, the liquid injection hole 13 is sealed.

Referring to fig. 5 in conjunction with fig. 4, fig. 5 is a schematic cross-sectional view of the electrode assembly 40 of fig. 4, the electrode assembly 40 including a first pole piece 43, a separator 47 and a second pole piece 44, the separator 47 separating the first pole piece 43 from the second pole piece 44; the electrode assembly 40 may be formed in a winding structure by winding a first pole piece 43, a second pole piece 44, and a separator 47 between the adjacent first and

second pole pieces

43 and 44 together; alternatively, the first pole piece 43, the second pole piece 44, and the separation film 47 between the adjacent first pole piece 43 and second pole piece 44 are stacked to form a laminated structure, wherein the separation film 47 is an insulator between the adjacent first pole piece 43 and second pole piece 44.

In the embodiment of the present application, the first pole piece 43 is exemplarily used as a positive pole piece, and the second pole piece 44 is exemplarily used as a negative pole piece. The positive electrode active material is coated on a partial region of the positive electrode current collector surface of the positive electrode tab, and the negative electrode active material is coated on a partial region of the negative electrode current collector surface of the negative electrode tab. As shown in fig. 4, a plurality of regions not coated with the positive electrode active material extending from the positive electrode current collector are laminated as a positive electrode tab 41; a plurality of regions not coated with the negative electrode active material extending from the negative electrode current collector are stacked as a negative electrode tab 42.

In one embodiment, the tab of the electrode assembly 40 is located at the end of the electrode assembly 40, the positive electrode tab 41 is connected to the positive electrode terminal through one connecting member 30, and the negative electrode tab 42 is connected to the negative electrode terminal through the other connecting member 30.

As shown in fig. 5, in an embodiment, when the electrode assembly 40 is formed by winding, the specific structure may be: the separator 47 includes a first separator 45 and a second separator 46, the first pole piece 43, the first separator 45, the second pole piece 44, and the second separator 46 are sequentially stacked and wound in the same direction to form a wound structure, and the end 461 of the second separator is located outside the end 451 of the first separator.

The ending section 451 of the first isolation film refers to the part of the first isolation film 45, which exceeds the first pole piece 43 along the winding direction; the ending section 461 of the second separation film refers to a portion of the second separation film 46 beyond the second pole piece 44 in the winding direction. At the end remote from the winding axis OO'. When the first pole piece 43 and the second pole piece 44 are terminated, the ending section 451 of the first isolation film and the ending section 461 of the second isolation film are attached to each other and continuously wound; when the ending section 451 of the first separation film ends, the ending section 461 of the second separation film is continuously wound to extend to the outside of the ending section 451 of the first separation film to cover the ending section 451 of the first separation film therein.

Since the separator 47 has a low porosity, the retention amount and retention time of the electrolyte are limited, and therefore, as shown in fig. 5, the battery cell 400 in the embodiment of the present application further includes a reservoir member 5, the reservoir member 5 being attached to the electrode assembly 40, the porosity of the reservoir member 5 being greater than the porosity of the separator 47.

For example, in one embodiment, the reservoir member 5 may be made of an insulating material, the reservoir member 5 is in the form of a flexible sheet, and the reservoir member 5 may be laminated or wound together with the pole pieces of the electrode assembly 40 and the separator 47, and finally fixed to the electrode assembly 40. The pole pieces are the general names of the first pole piece 43 and the second pole piece 44.

The liquid storage member 5 stores liquid in substantially the same manner as the separation film 47, and stores electrolyte by providing micropores, which means pores having a diameter of substantially less than 2 nm. Because the porosity of the liquid storage component 5 is large, in the single battery 400 using the liquid storage component 5, the retention amount of the electrode assembly 40 to the electrolyte is large, the retention time of the electrolyte is long, and the infiltration degree of the electrolyte to the electrode assembly 40 is improved, so that the charge and discharge performance of the single battery 400 is ensured, the service life of the single battery 400 is prolonged, and the use safety of the single battery 400 is improved.

In order to obtain the optimal porosity value of the liquid storage component 5, in experiment 1, cotton and glass fibers are respectively selected as the constituent materials of the liquid storage component 5, and the liquid absorption rate of the liquid storage component is tested under different porosities.

The experimental method of experiment 1 is: cutting liquid storage components 5 with different materials and different porosities into the same area, attaching the liquid storage components 5 to the same positions of the electrode assembly 40 by the same method, respectively placing the electrode assembly 40 with the liquid storage components 5 attached to the accommodating cavities of the shell 20, then introducing electrolyte into the accommodating cavities, taking the electrode assembly 40 out after standing for 10min, introducing the electrolyte remained in the shell 20 into a measuring cylinder to measure the volume, and utilizing the formula: the liquid-suction rate = (initial electrolyte-remaining electrolyte amount)/immersion time, and the liquid-suction rate of the reservoir member 5 at different porosities is calculated.

In addition, experiment 2 was also conducted, and experiment 2 was used to examine the liquid suction rate when the electrode assembly 40 without the reservoir member 5 was used, and only the separation film 47 of different porosity was replaced, to compare with the results in experiment 1.

The experimental method of experiment 2 is: selecting the isolating membranes 47 with the same material and different porosities, manufacturing the isolating membranes 47 with different porosities into the electrode assembly 40, placing the electrode assembly 40 containing the isolating membranes 47 with different porosities into the accommodating cavity of the shell 20, then introducing electrolyte into the accommodating cavity, standing for 10min, taking out the electrode assembly 40, introducing the remaining electrolyte in the shell 20 into a measuring cylinder to measure the volume, and utilizing the formula: the liquid-suction rate = (initial electrolyte-remaining electrolyte amount)/immersion time, and the liquid-suction rates of the different electrode assemblies 40 are calculated.

The specific experimental data for

experiments

1 and 2 are reported in table 1 below.

Material of	Porosity of the material	Initial amount of electrolyte (g)	Amount of residual electrolyte (g)	Imbibition rate ((initial electrolyte-remaining electrolyte amount)/soaking time)
					Cotton	32%	700	230	47
Cotton	57%	700	198	50.2
					Cotton	75%	700	239	46.1
Cotton	90%	700	210	49
					Glass fiber	32%	700	307	39.3
Glass fiber	45%	700	295	40.5
					Glass fiber	57%	700	174	52.6
Glass fiber	69%	700	279	42.1
					Isolation film	18%	700	486	21.4
Isolation film	23%	700	471	22.9
					Isolation film	28%	700	459	24.1

TABLE 1

As can be seen from a comparison of the data in table 1, the porosity of reservoir member 5 is greater than the porosity of separator 47, and the wicking rate of electrode assembly 40 incorporating reservoir member 5 is much greater than the wicking rate of electrode assembly 40 using separator 47 alone without reservoir member 5.

Thus, in some embodiments, the porosity of the reservoir member 5 is set to be 32% to 90%.

In one embodiment, the porosity of the separator 47 or reservoir 5 is determined according to Archimedes' principle, in which a sample is subjected to a hydrothermal method as follows:

1. first, the required dry weight of the sample is weighed as m₀The weighed sample is placed in a clean beaker, and distilled water is injected into the beaker until the sample is submerged.

2. And then, placing the beaker in a constant-temperature drying oven, heating to boil, and keeping the boiling state for 2 hours to ensure that the distilled water completely permeates into pores in the sample.

3. Then stopping heating to reduce the temperature of the sample to room temperature, then quickly taking out the sample, putting the sample into a supporting hanging basket prepared for weighing, hanging the hanging basket on a hanging hook of a balance to enable the sample to be continuously immersed in water, weighing the suspended weight of the saturated sample in the water, and recording the suspended weight as m₁。

4. The saturated sample was taken out, the surface of the saturated sample was carefully wiped off with a wet wipe, and the mass of the saturated sample was quickly weighed and recorded as m₂。

5. The porosity P of the sample is calculated by the formula: p = (m)₂-m₀）/(m₂-m₁)。

In the above experiment, the samples were different reservoir members 5 or separators 47.

In one embodiment, the liquid storage member 5 and the electrolyte have the same polarity, that is, both the liquid storage member 5 and the electrolyte are polar substances or non-polar substances, wherein the polar substances have hydrophilicity and lipophobicity, and the non-polar substances have lipophilicity and hydrophobicity. The electrolyte is usually an organic nonpolar solution, the wettability is greatly affected by the difference in polarity, according to the principle of similar intermiscibility, when the polarity of the liquid storage member 5 is the same as that of the electrolyte, the absorption and storage capacity of the liquid storage member 5 to the electrolyte is stronger, and when the electrolyte flows, the retention time at the contact interface with the liquid storage member 5 is longer, thereby further increasing the liquid retention capacity of the electrode assembly 40. For example, the reservoir member 5 may be fiberglass, polytetrafluoroethylene, or the like.

In one embodiment, the reservoir member 5 includes pores extending in the height direction of the battery cell 400. This structure can be achieved by adjusting the reservoir member 5 to such a degree that the extending direction of the aperture substantially coincides with the height direction of the battery cell 400 and is fixed when the battery cell 400 is assembled.

The pores of the separation film 47 in the electrode assembly 40 extend along the thickness direction of the separation film 47, and when the separation film 47 is applied to the battery cell 400, the pores are substantially perpendicular to the height direction of the battery cell 400, so that the separation film 47 cannot absorb the electrolyte from the bottom of the electrode assembly 40, and the upper part of the electrode assembly 40 is difficult to be soaked by the electrolyte in the case of insufficient electrolyte, and the pores of the liquid storage member 5 in this embodiment extend along the height direction of the battery cell 400, and can absorb the electrolyte from the bottom of the electrode assembly 40, or absorb the electrolyte from a position with a low liquid level to a high position, so that the holding capacity of the electrolyte is increased, and the soaking capacity of the electrolyte on the electrode assembly 40 is improved.

In the following embodiments, the specific arrangement of the liquid storage member 5 will be further described by taking the wound electrode assembly 40 as an example.

As shown in fig. 6, in some embodiments, the electrode assembly 40 further includes an adhesive tape 6, and the adhesive tape 6 is attached to an outer surface of the electrode assembly 40 to fix the tail 461 of the second separation film.

The adhesive tape 6 includes a base material and a bonding layer applied to an inner surface of the base material, wherein the inner surface of the base material means a surface of the base material on a side close to the electrode assembly 40. The base material can be polyvinyl chloride, polyethylene, polypropylene, polyethylene terephthalate, paper and other materials. The adhesive layer can be one or more of instant adhesive, epoxy resin adhesive, anaerobic adhesive, UV (Ultraviolet) adhesive, melt adhesive, pressure-sensitive adhesive and latex.

In some embodiments, the adhesive tape 6 is attached to the outer surface of the electrode assembly 40 and covers at least a portion of the finishing section 461 of the second separation film to fix the finishing section 461 of the second separation film, thereby preventing the electrode assembly 40 from being scattered.

In some embodiments, the substrate has micropores for the passage of an electrolyte.

In one embodiment, the porosity of the reservoir member 5 is greater than the porosity of the tape 6. The electrolyte permeating from the outside of the adhesive tape 6 can be stored in the reservoir member 5 as much as possible to enhance the retaining ability of the reservoir member 5 for the electrolyte.

In one embodiment, the reservoir member 5 is located on the side of the tape 6 adjacent to the winding axis OO' of the electrode assembly 40.

In the above embodiment, the liquid storage component 5 is closer to the pole piece, and the electrolyte stored in the liquid storage component 5 can reach the pole piece quickly, so as to ensure the charging and discharging performance of the electrode assembly 40.

In some embodiments, the reservoir member 5 is wound with the first and

second separators

45, 46. For example, the reservoir member 5 is located between the outermost pole piece and the tape 6. The liquid storage component 5 is located closer to the outer periphery of the electrode assembly 40 to absorb the electrolyte better, and meanwhile, the liquid storage component 5 is located closer to the outermost pole piece than the adhesive tape 6, so that the electrolyte stored in the liquid storage component 5 can reach the pole piece at a faster speed to meet the charging and discharging requirements of the electrode assembly 40.

In the above embodiment, the adhesive tape 6 can be used not only to fix the tail section 461 of the second isolation film, but also to fix the liquid storage member 5, so as to prevent the liquid storage member 5 from falling; moreover, the liquid storage member 5 does not obstruct the transmission of lithium ions between the first pole piece 43 and the second pole piece 44, and the stable charging and discharging process of the battery cell 40 is ensured.

The outermost pole piece refers to a pole piece farthest from the winding axis OO' in any direction with respect to the whole electrode assembly 40, and the pole piece may be the first pole piece 43 or the second pole piece 44, and in the whole circle range of the electrode assembly 40 along the winding direction, a part of the outermost pole piece may be the first pole piece 43, another part may be the second pole piece 44, or the whole circle may be the first pole piece 43, or the whole circle may be the second pole piece 44.

In one embodiment, for example, as shown in fig. 5 and 6, the electrode assembly 40 includes a flat region 401 and two bent regions 402 respectively connected to both ends of the flat region 401, the bent regions 402 are formed by the first pole piece 43, the second pole piece 44 and the separation film 47 turning during the winding process, the surface of the flat region 401 is substantially flat, and the surface of the bent regions 402 is at least partially curved.

In an embodiment of the present application, both ends of the liquid storage member 5 in the winding direction of the electrode assembly 40 are located in the bending region 402, so that steps are not generated at both ends of the liquid storage member 5 in the straight region 401, the flatness of the surface of the straight region 401 is ensured, the problem of stress concentration generated at the local position when the straight region 401 contacts other parts of the battery cell 400 is avoided, the risk of short circuit or damage of the electrode assembly 40 due to local stress concentration in the use process is reduced, the service life of the battery cell 400 is prolonged, and the use safety of the battery cell 400 is improved.

The two bending regions 402 are a first bending region and a second bending region, respectively.

In one embodiment, the two ends of the liquid storage member 5 in the winding direction of the electrode assembly 40 may be located at the two bending regions 402, respectively, for example, one end of the liquid storage member 5 is located at the first bending region, and the other end passes through the straight region 401 side to reach the second bending region and terminate; alternatively, one end of the liquid storage member 5 is located at the first bending region, and the other end of the liquid storage member is wound at least once along the forming direction of the electrode assembly 40 to reach the second bending region and end at the second bending region. The liquid storage member 5 passes through the flat region 401 at least once during the winding process, so that the area of the liquid storage member 5 is large, and more electrolyte is stored, thereby improving the wetting capability of the electrolyte on the electrode assembly 40.

Of course, in another embodiment, both ends of the liquid storage member 5 in the winding direction of the electrode assembly 40 may be located at the same bending region 402, for example, as shown in fig. 5, one end of the liquid storage member 5 is located at the first bending region, and the other end reaches the first bending region after being wound for about one or more turns along the forming direction of the electrode assembly 40 and terminates at the first bending region; alternatively, the reservoir member 5 is shorter and wound no more than one turn in the direction of formation of the electrode assembly 40, beginning and ending at the same fold region 402.

Fig. 5 and 6 only show the case where two ends of the liquid storage member 5 are located in the same inflection region 402, however, those skilled in the art should understand that two ends of the liquid storage member 5 are located in different inflection regions 402 according to the above description, and the description of the embodiment of the present application is omitted here.

As shown in fig. 7 and 8, in one embodiment, the liquid storage member 5 is attached to the adhesive tape 6 on a side away from the winding axis OO ', and is attached to the second isolation film 46, specifically, the end 461 of the second isolation film, on a side close to the winding axis OO'.

In one embodiment of the present application, as shown in fig. 7 and 8, in the thickness direction of the electrode assembly 40, the projection of the liquid storage member 5 covers the projection of the flat region 401, that is, the liquid storage member 5 passes through at least one side of the flat region 401, and is at least equal to the height of the flat region 401 in the height direction, wherein the thickness direction of the electrode assembly 40 is a direction perpendicular to the height direction of the electrode assembly 40 and perpendicular to the connecting line direction of the two bending regions 402, for example, the Y direction shown in fig. 4. In this embodiment, on the one hand, the area of the reservoir member 5 is large, increasing the amount of electrolyte retained in the electrode assembly 40; on the other hand, the liquid storage member 5 is capable of absorbing electrolyte from the bottom of the electrode assembly 40 and supplying it to the upper portion of the electrode assembly 40 to ensure normal charge and discharge of the electrode assembly 40; on the other hand, the end of the liquid storage member 5 does not fall on the flat region 401 of the electrode assembly 40, so that unevenness of the surface of the flat region 401 is avoided, indentation and wrinkling of the flat region 401 caused by stress concentration when the electrode assembly 40 is hot-pressed or expanded are avoided, and the risk of short circuit or damage of the electrode assembly 40 due to the indentation and the wrinkling is reduced.

As shown in fig. 9 and 10, in another embodiment, one side of the liquid storage member 5 away from the winding axis OO 'is attached to the second isolation film 46, specifically to the ending section 461 of the second isolation film, and one side of the liquid storage member 5 close to the winding axis OO' is attached to the first isolation film 45, specifically to the ending section 451 of the first isolation film, when assembling, one end of the liquid storage member 5 is sandwiched between the first isolation film 45 and the ending section 461 of the second isolation film to fix the two, and the liquid storage member 5 is wound around the first isolation film 45 and the second isolation film 46 simultaneously, which greatly reduces the attachment difficulty of the liquid storage member 5 and improves the assembly efficiency of the electrode assembly 40.

As shown in fig. 9 and 10, in another embodiment of the present application, the projection of the liquid storage member 5 in the thickness direction of the electrode assembly 40 may not completely cover the projection of the flat region 401 in that direction. For example, the liquid storage member 5 is wound only on the upper half of the electrode assembly 40, or only on the middle portion of the electrode assembly 40, or only on the lower half of the electrode assembly 40.

As shown in fig. 11 and 12, in another embodiment, the liquid storage member 5 is attached to the first separator 45, specifically to the end 451 of the first separator, on the side away from the winding axis OO ', and is attached to the second separator 46, specifically to the end 461 of the second separator, on the side close to the winding axis OO'.

As shown in fig. 11 and 12, in some other embodiments, the liquid storage member 5 includes multiple segments, each segment is wound only at different heights of the electrode assembly 40, and the segments of the liquid storage member 5 are separated from each other or overlap with each other, which is not limited by the embodiment of the present invention.

Alternatively, as shown in fig. 13 and 14, in one embodiment, the reservoir member 5 is attached to the electrode assembly 40 in a spirally wound manner.

Certainly, in some other embodiments, one side of the liquid storage member 5 near the winding axis OO' may also be directly attached to the outermost pole piece, and the shape and the winding manner of the liquid storage member 5 may be more various, which is not described herein again.

Further, it should be noted that, in fig. 7 to 14, although each drawing makes one of the combinations of the position and the structure of the liquid storage member 5, the above combination should not be construed as a limitation to the structure of the battery cell 400 of the present application.

In summary, in the battery cell 400 described above, the liquid storage member 5 is attached to the electrode assembly 40, and the porosity of the liquid storage member 5 is greater than the porosity of the separation film 47 of the existing electrode assembly 40, so that the porosity of the whole electrode assembly 40 is increased, the retention amount of the electrolyte in the electrode assembly 40 is increased, the infiltration degree of the electrolyte in the electrode assembly 40 is increased, the service life of the battery cell 400 is prolonged, and the safety of the battery cell 400 is improved without affecting the normal use of the electrode assembly 40.

The battery 200 and the electric device using the battery cell 400 have the same features as described above.

Another embodiment of the present application provides a method for preparing a battery cell, which is used to prepare the battery cell 400 described above in the present application, as shown in fig. 15, and includes the following steps:

s1: a first pole piece 43, a separator 47 and a second pole piece 44 are provided.

S2: a reservoir member 5 is provided, the porosity of the reservoir member 5 being greater than the porosity of the separator 47.

S3: a housing 20 having a receiving cavity is provided.

S4: the first pole piece 43, the separator 47, the second pole piece 44, and the reservoir member 5 are assembled such that the first pole piece 43, the separator 47, and the second pole piece 44 form the electrode assembly 40, and the reservoir member 5 is attached to the electrode assembly 40.

S5: the electrode assembly 40 is accommodated in the accommodation chamber.

The above sequence of the steps is not completely performed according to the above sequence, and during the actual manufacturing process of the battery cell 400, the sequence of the steps may be adjusted according to the actual situation, or performed simultaneously, or other steps may be added to manufacture other components of the battery cell 400, so as to finally obtain the required battery cell 400, for example: the sequence among S1, S2 and S3 can be interchanged or performed synchronously; s3 and S4 can be interchanged or synchronously performed; alternatively, the steps S1 and S2 may be performed first, then the steps S3 and S4 may be performed, and finally the step S5 may be performed, with specific reference to the embodiment of the battery cell 400.

Another embodiment of the present application also provides another method for preparing a battery cell, which is used for preparing the battery cell 400 described above in the present application, as shown in fig. 16, and includes the following steps:

s101: a first pole piece 43, a separator 47 and a second pole piece 44 are provided, said separator 47 comprising a first separator 45 and a second separator 46.

S102: an adhesive tape 6 is provided.

S103: a reservoir member 5 is provided, the porosity of the reservoir member 5 being greater than the porosity of the separator 47.

S104: a housing 20 having a receiving cavity is provided.

S105: assembling the first pole piece 43, the separator 47, the second pole piece 44 and the liquid storage member 5 such that the first pole piece 43, the first separator 45, the second pole piece 44 and the second separator 46 are stacked and formed in a winding structure to obtain the electrode assembly 40, wherein the end section 461 of the second separator is located outside the end section 451 of the first separator; and the reservoir member 5 is attached to the electrode assembly 40.

S106: the tape 6 is attached to the outer surface of the electrode assembly 40 to fix the finishing section 461 of the second separation film.

S107: the electrode assembly 40 is accommodated in the accommodation chamber.

Likewise, the sequence of the above steps of the present embodiment is not completely performed according to the above sequence, and in the actual manufacturing process of the battery cell 400, the sequence of the above steps may be adjusted according to the actual situation, or performed simultaneously, or other steps may be added to manufacture other components of the battery cell 400, so as to finally obtain the required battery cell 400, for example: the sequence of S101, S102, S103 and S104 can be interchanged or can be synchronously carried out; alternatively, the steps S101, S102, and S103 may be performed first, the steps S104, S105, and S106 may be performed, and the step S107 may be performed finally, with specific reference to the embodiment of the battery cell 400.

In addition, any method that can manufacture the related components and connect the related components falls within the scope of the embodiments of the present application, which are not described in detail herein.

The above-mentioned subject matters and features of the embodiments of the present application can be referred to each other, and those skilled in the art can flexibly combine technical features of different embodiments to form further embodiments when the structure allows. For example, in the claims, any of the claimed embodiments may be used in any combination.

The above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting 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 still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present application.

Claims

1. A battery cell, comprising:

an electrode assembly (40), the electrode assembly (40) comprising a first pole piece (43), a separator (47) and a second pole piece (44), the separator (47) for separating the first pole piece (43) and the second pole piece (44); the isolation film (47) comprises a first isolation film (45) and a second isolation film (46), and the first pole piece (43), the first isolation film (45), the second pole piece (44) and the second isolation film (46) are arranged in a stacked mode and wound to form a winding structure; the trailing section (461) of the second separator is located outside the trailing section (451) of the first separator; the electrode assembly (40) further comprises an adhesive tape (6), wherein the adhesive tape (6) is attached to the outer surface of the electrode assembly (40) to fix a tail section (461) of the second separation film; and

a reservoir member (5), the reservoir member (5) being attached to the electrode assembly (40), the porosity of the reservoir member (5) being greater than the porosity of the separator (47);

the electrode assembly (40) comprises a straight area (401) and two bending areas (402) which are respectively connected to two ends of the straight area (401); the two ends of the liquid storage component (5) in the winding direction of the electrode component (40) are respectively positioned at the two bending areas (402).

2. The battery cell according to claim 1, wherein the porosity of the reservoir member (5) is 32% to 90%.

3. The battery cell according to claim 1, wherein the liquid storage member (5) has the same polarity as the electrolyte.

4. The battery cell according to claim 1, wherein the reservoir member (5) comprises pores extending in a height direction of the battery cell (400).

5. The battery cell according to claim 1, wherein the porosity of the reservoir member (5) is greater than the porosity of the adhesive tape (6).

6. The battery cell according to claim 1, wherein the liquid storage member (5) is located on a side of the adhesive tape (6) close to a winding axis of the electrode assembly (40).

7. The battery cell according to claim 1, characterized in that the liquid storage member (5) is located between the outermost pole piece and the adhesive tape (6).

8. The battery cell according to claim 1, wherein the liquid storage member (5) is located between a trailing section (451) of the first separator film and a trailing section (461) of the second separator film.

9. The battery cell according to claim 1, wherein a projection of the reservoir member (5) covers a projection of the flat region (401) in a thickness direction of the electrode assembly (40).

10. A battery comprising a battery cell (400) according to any of claims 1-9.

11. An electric device, characterized in that it comprises a battery cell (400) according to any one of claims 1 to 9.

12. A method of manufacturing a battery cell for manufacturing a battery cell (400) according to any of claims 1-9, comprising the steps of:

providing a first pole piece (43), a separator film (47) and a second pole piece (44), wherein the separator film (47) comprises a first separator film (45) and a second separator film (46);

providing an adhesive tape (6);

providing a reservoir member (5), the porosity of the reservoir member (5) being greater than the porosity of the separator (47); providing a housing (20) having a receiving cavity;

assembling the first pole piece (43), the isolation film (47), the second pole piece (44) and the liquid storage component (5) to enable the first pole piece (43), the first isolation film (45), the second pole piece (44) and the second isolation film (46) to be arranged in a laminated mode and form a winding structure to obtain an electrode assembly (40), wherein a tail section (461) of the second isolation film is located on the outer side of a tail section (451) of the first isolation film; and attaching the reservoir member (5) to the electrode assembly (40); the electrode assembly (40) comprises a straight area (401) and two bending areas (402) which are respectively connected to two ends of the straight area (401); the two ends of the liquid storage component (5) in the winding direction of the electrode component (40) are respectively positioned in the two bending areas (402);

applying the adhesive tape (6) to the outer surface of the electrode assembly (40) to fix a finishing section (461) of the second separation film;

the electrode assembly (40) is received in the receiving cavity.