CN221041219U

CN221041219U - Electrode assembly, battery cell, battery and electricity utilization device

Info

Publication number: CN221041219U
Application number: CN202322490922.2U
Authority: CN
Inventors: 王文轩; 王国宝; 李永发
Original assignee: Contemporary Amperex Technology Co Ltd
Current assignee: Contemporary Amperex Technology Co Ltd
Priority date: 2023-09-13
Filing date: 2023-09-13
Publication date: 2024-05-28
Anticipated expiration: 2033-09-13

Abstract

The application discloses an electrode assembly, a battery cell, a battery and an electric device, wherein the electrode assembly is a winding type electrode assembly and comprises a first pole piece, a first isolating film, a second isolating film and a heat conducting piece, at least one of two ends of the first isolating film exceeds the first pole piece in the winding direction to form a first diaphragm part, at least one of two ends of the second isolating film exceeds the first pole piece to form a second diaphragm part, the heat conducting piece is arranged between the first diaphragm part and the second diaphragm part which are oppositely arranged and is in heat conducting fit with the first diaphragm part and the second diaphragm part respectively, and the heat conducting coefficient of the heat conducting piece is larger than that of the first diaphragm part and the second diaphragm part. According to the electrode assembly, the uniformity of temperature distribution on the electrode assembly can be improved, so that the use reliability of the electrode assembly is improved, and meanwhile, the safety of the electrode assembly and the energy density of a battery cell can be considered to a certain extent.

Description

Electrode assembly, battery cell, battery and electricity utilization device

Technical Field

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

Background

In the related art, when the battery cell is operated, the electrode assembly generates heat, so that the internal temperature of the battery cell is increased; the battery cell has larger and larger capacity requirements and larger volume of the electrode assembly, so that the temperature on the electrode assembly is easy to be in unbalanced distribution, and the electrode assembly is easy to generate failure problems such as lithium precipitation and the like.

Disclosure of utility model

The application provides an electrode assembly, a battery cell, a battery and an electricity utilization device, which can improve the balance of temperature distribution on the electrode assembly, thereby improving the use reliability of the electrode assembly, and simultaneously can consider the safety of the electrode assembly and the energy density of the battery cell to a certain extent.

In a first aspect, an embodiment of the present application provides an electrode assembly, where the electrode assembly is a wound electrode assembly and includes a first electrode sheet, a first separator, a second separator, and a heat conductive member, where the first electrode sheet is disposed between the first separator and the second separator, at least one of two ends of the first separator exceeds the first electrode sheet in a winding direction to form a first separator, at least one of two ends of the second separator exceeds the first electrode sheet to form a second separator, and the heat conductive member is disposed between the first separator and the second separator, which are disposed opposite to each other, and is in heat conductive fit with the first separator and the second separator, respectively, and a heat conductivity coefficient of the heat conductive member is greater than that of the first separator and the second separator.

According to the technical scheme, at least one of the two ends of the first isolating film in the winding direction exceeds the first pole piece to form the first diaphragm part, at least one of the two ends of the second isolating film in the winding direction exceeds the first pole piece to form the second diaphragm part, the heat conducting piece is arranged between the first diaphragm part and the second diaphragm part, the heat conducting capacity of the heat conducting piece is better than that of the first diaphragm part and the second diaphragm part, the heat conducting piece can conduct heat of a part with higher temperature on the electrode assembly to a part with lower temperature on the electrode assembly so as to reduce the difference value between the highest temperature and the lowest temperature of the electrode assembly, the balance of temperature distribution on the electrode assembly is improved, the risk of failure problems such as lithium precipitation and the like of the electrode assembly is reduced, and the use reliability of the electrode assembly is improved; meanwhile, the arrangement of the heat conducting piece basically does not influence the insulating property of the first isolating film and the second isolating film, excessively increases the winding thickness of the electrode assembly and excessively increases the weight of the electrode assembly, so that the safety of the electrode assembly and the energy density of the battery cell are simultaneously considered.

In some embodiments, the thermal conductivity of the thermally conductive member is greater than 10 times the thermal conductivity of the first and second diaphragm portions; and/or the heat conductive member has a heat conductivity of more than 10W/(mK).

According to the technical scheme, the heat conduction coefficient of the heat conduction piece is 10 times greater than that of the first diaphragm part and the second diaphragm part, and/or the heat conduction coefficient of the heat conduction piece is greater than 10W/(m.K), so that the heat conduction piece has remarkable heat conduction capacity relative to the first diaphragm part and the second diaphragm part, and has high heat conduction capacity, so that heat of a part with higher temperature on the electrode assembly is quickly conducted to other parts with lower temperature on the electrode assembly, and timeliness and rapidity of temperature on the electrode assembly, which tend to be evenly distributed, are improved.

In some embodiments, the heat conductive member is an insulating member, and both end edges of the first separator part and both end edges of the second separator part are flush with corresponding both end edges of the heat conductive member, respectively, in an axial direction of the electrode assembly.

In the above technical scheme, through setting up the heat conduction piece and be the insulating part, and the both ends border of first diaphragm portion and the both ends border of second diaphragm portion flush with the corresponding both ends border of heat conduction piece respectively in the axial of electrode assembly, can not make the inside easy under the prerequisite that takes place the short circuit of electrode assembly at the heat conduction piece, can increase the heat conduction area of heat conduction piece to a certain extent simultaneously, be favorable to promoting the timeliness and the rapidity that the temperature tends to equilibrium distribution on the electrode assembly.

In some embodiments, the heat conductive member is an electrically conductive member, and in an axial direction of the electrode assembly, both end edges of the first separator part extend beyond corresponding both end edges of the heat conductive member, respectively, and both end edges of the second separator part extend beyond corresponding both end edges of the heat conductive member, respectively.

In the above technical scheme, through setting up the heat conduction piece and be electrically conductive piece, and extend to the corresponding both ends border that surpasss the heat conduction piece respectively at the both ends border of first diaphragm portion and the both ends border of second diaphragm portion in the axial of electrode assembly for there is certain interval respectively at the both ends border of heat conduction piece and the corresponding both ends border of first diaphragm portion, and there is certain interval respectively at the both ends border of heat conduction piece and the corresponding both ends border of second diaphragm portion, so that further reduction heat conduction piece is to the influence of the insulating ability of first barrier film and second barrier film, reduces the risk that the electrode assembly takes place the short circuit, is favorable to promoting the security of electrode assembly. I.e., the above arrangement is convenient so that the electrode assembly does not raise the risk of short circuit due to the arrangement of the heat conductive member.

In some embodiments, in the axial direction of the electrode assembly, a distance between the edges of the two ends of the heat conductive member and the corresponding edges of the first separator portion is x.ltoreq.20 mm, and a distance between the edges of the two ends of the heat conductive member and the corresponding edges of the second separator portion is y.ltoreq.20 mm.

In the above technical scheme, through setting up the interval less than or equal to 20mm between the both ends border of heat conduction spare in electrode assembly axial and first diaphragm portion corresponding border, second diaphragm portion corresponding border to under the prerequisite that makes the setting of heat conduction spare compromise the insulating properties of first barrier film and second barrier film, compromise heat conduction area and the heat conduction effect of heat conduction spare simultaneously, thereby be convenient for compromise simultaneously insulating properties of first barrier film, second barrier film and improve electrode assembly's temperature distribution.

In some embodiments, 8 mm.ltoreq.x.ltoreq.12 mm,8 mm.ltoreq.y.ltoreq.12 mm.

In the above technical scheme, the distance between the edge of the heat conducting piece and the corresponding edge of the first diaphragm part and the corresponding edge of the second diaphragm part are further limited, so that the arrangement of the heat conducting piece can further and better give consideration to the insulation performance of the first isolation film and the second isolation film and improve the temperature distribution of the electrode assembly.

In some embodiments, the thermally conductive member has a thickness t.ltoreq.50 μm.

In the technical scheme, the thickness t of the heat conducting piece is less than or equal to 50 mu m, so that the winding thickness and the weight of the electrode assembly are considered on the premise that the heat conducting effect of the heat conducting piece is considered in the setting of the heat conducting piece, and the temperature distribution of the electrode assembly, the volume energy density and the mass energy density of the battery unit are improved conveniently.

In some embodiments, the thermally conductive member has a thickness t of 10 μm.ltoreq.t.ltoreq.20 μm.

In the above technical scheme, by further limiting the thickness of the heat conducting member, the arrangement of the heat conducting member can be further and better achieved while improving the temperature distribution of the electrode assembly and the energy density of the battery cell.

In some embodiments, the thermally conductive member is a non-phase change material member.

In the technical scheme, the heat conducting piece is a non-phase change material piece, so that the stability of the heat conducting piece is improved, and the safety and the reliability of the electrode assembly are improved conveniently.

In some embodiments, the thermally conductive member comprises a metallic layer and/or a non-metallic layer.

Among the above-mentioned technical scheme, through setting up the heat conduction spare and including metal level and/or nonmetallic layer, be convenient for under the prerequisite of improving electrode assembly temperature distribution, realize the nimble material selection of heat conduction spare, make things convenient for the setting of heat conduction spare, and be convenient for satisfy actual differentiation demand.

In some embodiments, the metal layer comprises one or more of an aluminum layer, a copper layer, an iron layer, a silver layer, a gold layer, a tin layer, and a lead layer, and the non-metal layer comprises one or more of a graphene layer, a graphite layer, an aluminum nitride layer, a silicon carbide layer, and a thermally conductive silicone grease layer.

In the above technical scheme, by arranging the structures of the metal layer and the nonmetal layer, the heat conducting piece has good heat conducting capacity, so that the temperature distribution of the electrode assembly is effectively improved, and the temperature distribution of the electrode assembly is more balanced.

In some embodiments, the heat conducting member includes a metal layer and a non-metal layer, the metal layer is a plurality of layers, and the metal layer is respectively disposed between the non-metal layer and the first diaphragm portion, and between the non-metal layer and the second diaphragm portion.

According to the technical scheme, the thermal layer comprises the metal layer and the nonmetal layer, and the metal layer is arranged between the nonmetal layer and the first diaphragm part and between the nonmetal layer and the second diaphragm part respectively, so that the metal layer separates the first diaphragm part from the nonmetal layer and separates the second diaphragm part from the nonmetal layer, and the metal layer and the nonmetal layer are arranged conveniently.

In a second aspect, an embodiment of the present application provides a battery cell, including the above-described electrode assembly.

In the above technical scheme, the battery monomer adopts the electrode assembly, and the temperature distribution on the electrode assembly is relatively balanced, so that the use reliability and the safety of the battery monomer can be improved, and the energy density of the battery monomer can be considered.

In a third aspect, an embodiment of the present application provides a battery, including the above-mentioned battery cell.

In the technical scheme, the battery adopts the battery monomer, and the use reliability and the safety of the battery monomer are improved, so that the use reliability and the safety of the battery can be improved.

In a fourth aspect, an embodiment of the present application provides an electrical device, including the above battery, where the battery is used to provide electrical energy.

In the technical scheme, the battery is adopted by the power utilization device, and the use reliability and the safety of the battery are good, so that the use reliability and the safety of the power utilization device are improved.

Drawings

The foregoing and/or additional aspects and advantages of the application will become apparent and may be better understood from the following description of embodiments taken in conjunction with the accompanying drawings in which:

fig. 1 is a schematic structural diagram of an electric device according to some embodiments of the present application;

fig. 2 is a schematic structural diagram of a battery according to some embodiments of the present application;

fig. 3 is a schematic structural diagram of a battery cell according to some embodiments of the present application;

FIG. 4 is a schematic view of an electrode assembly provided in some embodiments of the application;

Fig. 5 is an exploded view of the electrode assembly shown in fig. 4;

FIG. 6 is a partial cross-sectional view of the electrode assembly of FIG. 4;

FIG. 7 is a schematic view of an electrode assembly according to further embodiments of the present application;

fig. 8 is an exploded view of the electrode assembly shown in fig. 7, without showing a heat conductive member;

FIG. 9 is a schematic view of an electrode assembly provided in accordance with further embodiments of the present application;

fig. 10 is an exploded view of the electrode assembly shown in fig. 9, without the heat conductive member shown.

Reference numerals:

Electric device 1000, battery cell 100, case 101, first case 101a, second case 101b,

Battery 200, controller 300, motor 400,

Electrode assembly 10, case 20,

A first pole piece 11, a second pole piece 12, a first isolating film 13, a first diaphragm portion 131, a third diaphragm portion 132, a second isolating film 14, a second diaphragm portion 141, a fourth diaphragm portion 142,

A heat conductive member 15.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present application more apparent, the technical solutions of the embodiments of the present application will be clearly described below with reference to the accompanying drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments of the present application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the 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 of the application and the claims and the description of the drawings above are intended to cover a non-exclusive inclusion. The terms first, second and the like in the description and in the claims or in the above-described figures, are used for distinguishing between different objects and not necessarily for describing a particular sequential or chronological order.

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

The term "and/or" in the present application is merely an association relation describing the association object, and indicates that three kinds of relations may exist, for example, a and/or B may indicate: a exists alone, A and B exist together, and B exists alone. In the present application, the character "/" generally indicates that the front and rear related objects are an or relationship.

In the embodiments of the present application, the same reference numerals denote the same components, and detailed descriptions of the same components are omitted in different embodiments for the sake of brevity. It should be understood that the dimensions of the various components, such as thickness, distance between two components, etc., in the embodiments of the application illustrated in the figures are merely exemplary and should not be construed as limiting the application in any way.

The term "plurality" as used herein refers to two or more (including two).

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 embodiment of the present application. The battery cell may be in a cylindrical shape, a flat shape, a rectangular parallelepiped shape, or other shapes, which is not limited in this embodiment of the application. The battery cells are generally classified into three types according to the packaging method: the cylindrical battery cell, the square battery cell and the soft package battery cell are not limited in this embodiment.

Reference to a battery in accordance with an embodiment of the present application refers to a single physical module that includes multiple battery cells to provide higher voltage and capacity. For example, the battery referred to in the present application may be a battery module, a battery pack, or the like. The battery module generally includes a plurality of battery cells. The battery generally comprises a box body for packaging a plurality of battery cells or a plurality of battery modules, wherein the box body can prevent liquid or other foreign matters from affecting the charge or discharge of the battery cells; of course, the battery may not include a case.

For example, the battery cell may generally include a housing for receiving the cell assembly and the electrolyte, the housing having at least one positive electrode post and at least one negative electrode post disposed thereon. The battery cell assembly comprises one or more electrode assemblies, and the electrode assemblies are formed by winding a positive electrode plate, a negative electrode plate and a separation film.

The positive electrode sheet may generally include a positive electrode current collector and a positive electrode active material layer, the positive electrode active material layer is directly or indirectly coated on the positive electrode current collector, the positive electrode current collector without the positive electrode active material layer protrudes from the positive electrode current collector coated with the positive electrode active material layer, the positive electrode current collector without the positive electrode active material layer serves as a positive electrode tab, and a plurality of positive electrode tabs are stacked together and electrically connected with the positive electrode tab. Illustratively, a plurality of positive electrode tabs stacked together may be welded directly to the positive electrode post to form an electrical connection; or the battery cell assembly may further include a positive electrode tab, a plurality of positive electrode tabs stacked together are welded with one end of the positive electrode tab, and the other end of the positive electrode tab is welded to the positive electrode post so that the positive electrode tab is electrically connected with the positive electrode post.

The negative electrode tab may generally include a negative electrode current collector and a negative electrode active material layer, the negative electrode active material layer being directly or indirectly coated on the negative electrode current collector, the negative electrode current collector without the negative electrode active material layer protruding from the negative electrode current collector with the coated negative electrode active material layer, the negative electrode current collector without the negative electrode active material layer being a negative electrode tab, the plurality of negative electrode tabs being stacked together and electrically connected to the negative electrode tab. Illustratively, a plurality of negative electrode tabs stacked together may be welded directly to the negative electrode post to form an electrical connection; or the cell assembly may further include a negative electrode tab, a plurality of negative electrode tabs stacked together being welded to one end of the negative electrode tab, the other end of the negative electrode tab being welded to the negative electrode post so that the negative electrode tab is electrically connected to the negative electrode post. The material of the separator is not limited, and may be, for example, polypropylene or polyethylene.

In recent years, new energy automobiles have been developed dramatically, and in the field of electric automobiles, batteries play an important role as a power source of the electric automobiles. The battery is used as a core part of a new energy automobile, and has high requirements in terms of energy density and reliability.

For example, in the case of a relatively large-sized electrode assembly, the main heat generating location is located at the tab during the cycle, and the temperature distribution on the electrode assembly is uneven due to factors of the size and heat dissipation capability of the electrode assembly, and the temperature difference is relatively large, for example, the temperature difference range is generally 5 to 60 ℃, so that lithium precipitation easily occurs at a relatively high temperature location on the electrode assembly, resulting in failure of the electrode assembly.

Based on the above-mentioned considerations, in order to improve the temperature distribution of the electrode assembly, an electrode assembly is proposed, which is a wound electrode assembly and includes a first separator, a second separator, and a heat conductive member, the first separator is disposed between the first separator and the second separator, at least one of both ends of the first separator exceeds the first separator in a winding direction to form a first separator, at least one of both ends of the second separator exceeds the first separator to form a second separator, the heat conductive member is disposed between the first separator and the second separator which are disposed opposite to each other, and is in heat conductive engagement with the first separator and the second separator, respectively, and the heat conductive coefficient of the heat conductive member is greater than the heat conductive coefficients of the first separator and the second separator.

The embodiment of the application provides an electricity utilization device using a battery as a power supply, wherein the electricity utilization device can be, but is not limited to, a mobile phone, a flat plate, a notebook computer, an electric toy, an electric tool, a battery car, an electric automobile, a ship, a spacecraft and the like. Among them, the electric toy may include fixed or mobile electric toys, such as game machines, electric car toys, electric ship toys, electric plane toys, and the like, and the spacecraft may include planes, rockets, space planes, and spacecraft, and the like.

For convenience of explanation, the following embodiments describe the structures of the power consumption device 1000, the battery 200, and the battery cell 100 according to the present application in detail, taking the power consumption device 1000 as an example of a vehicle.

Referring to fig. 1, fig. 1 is a schematic structural diagram of an electric device 1000 according to some embodiments of the application. The vehicle can be a fuel oil vehicle, a fuel 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-extended vehicle and the like. The vehicle is provided with a battery 200, and the battery 200 may be provided at the bottom or at the head or at the tail of the vehicle. The battery 200 may be used for power supply of a vehicle, for example, the battery 200 may be used as an operating power source of the vehicle. The vehicle may also include a controller 300 and a motor 400, the controller 300 being configured to control the battery 200 to power the motor 400, for example, for operating power requirements during start-up, navigation, and travel of the vehicle. In some embodiments of the application, the battery 200 may be used not only as an operating power source for a vehicle, but also as a driving power source for a vehicle to supply driving power to the vehicle instead of or in part instead of fuel oil or natural gas.

Referring to fig. 2, fig. 2 is an exploded view of a battery cell 100 for a battery 200 according to some embodiments of the present application. The battery 200 includes a case 101 and a plurality of battery cells 100, and the battery cells 100 are accommodated in the case 101. The case 101 is used to provide an assembly space for the battery cell 100, and the case 101 may have various structures. In some embodiments, the case 101 may include a first case 101a and a second case 101b, the first case 101a and the second case 101b being overlapped with each other, the first case 101a and the second case 101b together defining a receiving chamber for receiving the battery cell. The second casing 101b may have a hollow structure with one end opened, and the first casing 101a may have a plate-shaped structure, where the first casing 101a covers the open side of the second casing 101b, so that the first casing 101a and the second casing 101b together define a receiving cavity; alternatively, the first case 101a and the second case 101b may each have a hollow structure (for example, as shown in fig. 2) with one side open, and the open side of the first case 101a is closed to the open side of the second case 101 b. Of course, the case 101 formed by the first case 101a and the second case 101b may be various shapes, such as a cylinder, a rectangular parallelepiped, or the like.

In the battery 200, the plurality of battery cells 100 may be connected in series, parallel, or a series-parallel connection, where a series-parallel connection refers to both the plurality of battery cells 100 being connected in series and parallel. The plurality of battery cells 100 can be directly connected in series, parallel or series-parallel, and then the whole formed by the plurality of battery cells 100 is accommodated in the box body 101; or the battery 200 may be a battery module form formed by connecting a plurality of battery cells 100 in series, parallel or series-parallel connection, and then connecting a plurality of battery modules in series, parallel or series-parallel connection to form a whole and be accommodated in the case 101. The battery 200 may also include other structures, for example, the battery 200 may also include a bus bar for making electrical connection between the plurality of battery cells 100.

Referring to fig. 3, fig. 3 is a schematic structural diagram of a battery cell 100 according to some embodiments of the application. The battery cell has a rectangular parallelepiped shape, but is not limited thereto, and in other embodiments of the present application, the battery cell may have a polygonal prism shape, a flat shape, or other shapes.

Referring to fig. 4 to 10, fig. 4 is a schematic view of an electrode assembly according to some embodiments of the present application, fig. 5 is an exploded view of the electrode assembly shown in fig. 4, fig. 6 is a partial sectional view of the electrode assembly shown in fig. 4, fig. 7 is a schematic view of the electrode assembly according to other embodiments of the present application, fig. 8 is an exploded view of the electrode assembly shown in fig. 7, fig. 9 is a schematic view of the electrode assembly according to still other embodiments of the present application, and fig. 10 is an exploded view of the electrode assembly shown in fig. 9. In the embodiment of the present application, the electrode assembly 10 is a wound electrode assembly, and the electrode assembly 10 includes a first electrode sheet 11, a first separator 13, a second separator 14, and a heat conductive member 15, the first electrode sheet 11 being disposed between the first separator 13 and the second separator 14. At least one of the two ends of the first separation film 13 exceeds the first pole piece 11 in the winding direction to form a first diaphragm portion 131, and at least one of the two ends of the second separation film 14 exceeds the first pole piece 11 to form a second diaphragm portion 141.

As can be seen, in the above arrangement, the portion of the first separator 13 beyond the first electrode sheet 11 at either end of the electrode assembly 10 in the winding direction is formed as a first separator portion 131, and the first separator 13 further includes a third separator portion 132, the third separator portion 132 being overlapped with the first electrode sheet 11; also, a portion of the second separator 14, which exceeds the first electrode sheet 11 at either end of the electrode assembly 10 in the winding direction, is formed as a second separator portion 141, and the second separator 14 further includes a fourth separator portion 142, the fourth separator portion 142 being overlapped with the first electrode sheet 11, the first electrode sheet 11 being disposed between the third separator portion 132 and the fourth separator portion 142, and the first separator portion 131 being disposed offset from the first electrode sheet 11 and the second separator portion 141 being disposed offset from the first electrode sheet 11 in the winding direction of the electrode assembly 10.

Thus, before the coil material configured as the electrode assembly 10 is wound, a portion of the first separator 13 where the first electrode sheet 11 is laminated (hereinafter, referred to as a first portion) corresponds to the third separator portion 132, other portions of the first separator 13 where the first portion is provided at either end in the coil length direction (hereinafter, referred to as a second portion) correspond to the first separator portion 131, and the second portion is provided offset from the first electrode sheet 11 in the coil length direction; similarly, a portion of the second separator 14 stacked on the first pole piece 11 (hereinafter referred to as a third portion) corresponds to the fourth separator 142, the other portion of the second separator 14 provided at either end of the third portion in the web longitudinal direction (hereinafter referred to as a fourth portion) corresponds to the second separator 141, and the fourth portion is provided offset from the first pole piece 11 in the web longitudinal direction.

When the first portion is provided with the second portion at one of both ends in the coil length direction, the second portion may be formed into the first separator 131 after the electrode assembly 10 is wound and molded, and the first separator 131 may be located at the inner ring of the electrode assembly 10 or at the outer ring of the electrode assembly 10; when the first portions are provided with the second portions at both ends in the coil length direction, respectively, each of the second portions may be formed into the first separator portions 131, respectively, after the electrode assembly 10 is wound and molded, one of the first separator portions 131 may be positioned at the inner ring of the electrode assembly 10, and the other first separator portion 131 may be positioned at the outer ring of the electrode assembly 10. Also, when the third portion is provided with the fourth portion at one of both ends in the web length direction, the fourth portion may be formed as the second separator 141 after the electrode assembly 10 is wound and molded, and the second separator 141 may be located at the inner ring of the electrode assembly 10 or at the outer ring of the electrode assembly 10; when the third portions are provided with the fourth portions at both ends in the length direction of the web, respectively, each of the fourth portions may be formed as the second separator portions 141, respectively, after the electrode assembly 10 is wound and molded, one of the second separator portions 141 may be positioned at the inner ring of the electrode assembly 10, and the other second separator portion 141 may be positioned at the outer ring of the electrode assembly 10.

In other words, the length of the first separator 13 is greater than the length of the first electrode sheet 11 in the winding direction of the electrode assembly 10, the length of the second separator 14 is greater than the length of the first electrode sheet 11, and a portion of either one of the two ends of the first separator 13, which is greater than the first electrode sheet 11, is formed as the first separator portion 131, and a portion of either one of the two ends of the second separator 14, which is greater than the first electrode sheet 11, is formed as the second separator portion 141 in the winding direction of the electrode assembly 10.

Wherein the heat conductive member 15 is disposed between the first diaphragm portion 131 and the second diaphragm portion 141 which are disposed opposite to each other.

For example, the inner ring of the electrode assembly 10 has a first separator part 131, and the inner ring of the electrode assembly 10 has a second separator part 141; or the outer ring of the electrode assembly 10 has a first separator part 131, and the outer ring of the electrode assembly 10 has a second separator part 141; or the inner ring and the outer ring of the electrode assembly 10 have the first separator part 131, respectively, and the inner ring of the electrode assembly 10 has the second separator part 141, in which case the heat conductive member 15 may be disposed between the second separator part 141 and the first separator part 131 located at the inner ring; or the inner ring and the outer ring of the electrode assembly 10 have the first separator part 131, respectively, and the outer ring of the electrode assembly 10 has the second separator part 141, in which case the heat conductive member 15 may be disposed between the second separator part 141 and the first separator part 131 located at the outer ring; or the inner ring of the electrode assembly 10 has the first separator part 131, and the inner ring and the outer ring of the electrode assembly 10 have the second separator parts 141, respectively, in which case the heat conductive member 15 may be disposed between the first separator part 131 and the second separator part 141 located at the inner ring; or the outer ring of the electrode assembly 10 has the first diaphragm portion 131, and the inner ring and the outer ring of the electrode assembly 10 have the second diaphragm portion 141, respectively, in which case the heat conductive member 15 may be disposed between the first diaphragm portion 131 and the second diaphragm portion 141 located at the outer ring; or the inner ring and the outer ring of the electrode assembly 10 respectively have the first diaphragm portion 131, and the inner ring and the outer ring of the electrode assembly 10 respectively have the second diaphragm portion 141, at this time, a heat conduction member 15 is provided between the first diaphragm portion 131 located at the inner ring and the second diaphragm portion 141 located at the outer ring, and/or a heat conduction member 15 is provided between the first diaphragm portion 131 located at the outer ring and the second diaphragm portion 141 located at the outer ring.

In other words, for one of the two ends of the first separator 13 in the winding direction beyond the first pole piece 11 to form the first diaphragm portion 131, and one of the two ends of the second separator 14 in the winding direction beyond the first pole piece 11 to form the second diaphragm portion 141: for example, referring to fig. 7 and 8, the first separator 131 and the second separator 141 are both positioned at the inner ring of the electrode assembly 10, and the heat conducting member 15 is also positioned at the inner ring of the electrode assembly 10; for example, referring to fig. 9 and 10, the first separator 131 and the second separator 141 are both positioned on the outer ring of the electrode assembly 10, and the heat conducting member 15 is also positioned on the outer ring of the electrode assembly 10. For another example, for the first separator 13 having both ends in the winding direction respectively beyond the first pole piece 11 to form the first diaphragm portion 131, and the second separator 14 having both ends in the winding direction respectively beyond the first pole piece 11 to form the second separator 141, respectively: in example three, a heat conducting member 15 is disposed between the first diaphragm portion 131 located at the inner ring and the second diaphragm portion 141 located at the inner ring, and no heat conducting member 15 is disposed between the first diaphragm portion 131 located at the outer ring and the second diaphragm portion 141 located at the outer ring; in example four, the heat conducting member 15 is disposed between the first diaphragm portion 131 located at the outer ring and the second diaphragm portion 141 located at the outer ring, and the heat conducting member 15 is not disposed between the first diaphragm portion 131 located at the inner ring and the second diaphragm portion 141 located at the inner ring; example five: referring to fig. 4 and 5, a heat conducting member 15 is disposed between the first diaphragm portion 131 located at the inner ring and the second diaphragm portion 141 located at the inner ring, and a heat conducting member 15 is also disposed between the first diaphragm portion 131 located at the outer ring and the second diaphragm portion 141 located at the outer ring.

Of course, the present application is not limited thereto. In still other examples, both ends of the first separator 13 in the winding direction respectively exceed the first pole pieces 11 to form first separator portions 131, respectively, one of both ends of the second separator 14 in the winding direction exceeds the first pole pieces 11 to form second separator portions 141, the second separator portions 141 being disposed opposite to one of the first separator portions 131 with the heat conductive member 15 interposed therebetween; one of the two ends of the first separator 13 in the winding direction extends beyond the first pole piece 11 to form a first separator 131, the two ends of the second separator 14 in the winding direction extend beyond the first pole piece 11 to form second separator 141, the first separator 131 is disposed opposite to one of the second separator 141 with the heat conductive member 15 therebetween.

The heat conducting member 15 is in heat conducting engagement with the first diaphragm portion 131 and the second diaphragm portion 141, respectively, the heat conducting coefficient of the heat conducting member 15 is larger than that of the first diaphragm portion 131, and the heat conducting coefficient of the heat conducting member 15 is larger than that of the second diaphragm portion 141.

Note that, the heat conducting member 15 is in heat conducting fit with the first diaphragm portion 131, which means that heat exchange is formed between the heat conducting member 15 and the first diaphragm portion 131, and heat transfer exists between the heat conducting member 15 and the first diaphragm portion 131, and the heat conducting member 15 and the first diaphragm portion 131 may be in direct contact to achieve heat conduction, or the heat conducting member 15 and the first diaphragm portion 131 achieve heat conduction through other heat conducting structures, such as heat conducting glue, etc.; the heat conducting member 15 and the second diaphragm portion 141 are in heat conducting fit, which means that heat exchange is formed between the heat conducting member 15 and the second diaphragm portion 141, and heat transfer exists between the heat conducting member 15 and the second diaphragm portion 141, and the heat conducting member 15 and the second diaphragm portion 141 can be in direct contact to achieve heat conduction, or the heat conducting member 15 and the second diaphragm portion 141 achieve heat conduction through other heat conducting structures such as heat conducting glue.

The heat conductive member 15 has good heat conductive ability and is superior to the first separator 131 and the second separator 141 in order to conduct heat from a higher temperature portion of the electrode assembly 10 to other lower temperature portions of the electrode assembly 10, for example, the heat conductive member 15 can conduct heat from a higher temperature portion of the first separator 13 to other lower temperature portions of the first separator 13 and/or to a lower temperature portion of the second separator 14, etc., and the heat conductive member 15 can conduct heat from a higher temperature portion of the second separator 14 to other lower temperature portions of the second separator 14 and/or to a lower temperature portion of the first separator 13, etc., so as to reduce the difference between the highest temperature and the lowest temperature of the electrode assembly 10, promote the uniformity of the temperature distribution of the electrode assembly 10, and in particular, can improve the temperature distribution of the electrode assembly 10 in its axial direction, reduce the temperature difference of the electrode assembly 100 in its axial direction, and at the same time facilitate reducing the temperature difference of the electrode assembly 10, thereby reducing the risk of failure of the electrode assembly 10, such as the occurrence of lithium lift, etc., of the reliability of the electrode assembly 10.

Wherein, when the inner and outer rings of the electrode assembly 10 are respectively provided with the heat conductive members 15, not only the temperature distribution of the electrode assembly 10 in the axial direction thereof can be improved, but also the temperature distribution of the electrode assembly 10 in the radial direction thereof can be improved, and the temperature difference between the inside and outside of the electrode assembly 100 can be reduced, thereby being beneficial to reducing the temperature difference of the electrode assembly 10 in the width direction and the thickness direction.

In addition, in the above technical solution, even if the heat conducting member 15 has the electrical conductivity, the arrangement of the heat conducting member 15 does not substantially affect the insulation performance of the first and second insulating films 13 and 14, so that the arrangement of the heat conducting member 15 does not substantially increase the risk of the electrode assembly 10 being short-circuited, regardless of whether the heat conducting member 15 has the electrical conductivity, so that the safe arrangement of the electrode assembly 10 is facilitated. Also, since the heat conductive member 15 is provided at the inner and/or outer rings of the electrode assembly 10, the provision of the heat conductive member 15 does not excessively increase the winding thickness of the electrode assembly 10 nor excessively increase the weight of the electrode assembly 10, thereby not excessively reducing the volumetric energy density and the mass energy density of the battery cell 100.

Therefore, in the above technical solution, the arrangement of the heat conducting member 15 can improve the temperature distribution uniformity of the electrode assembly 10 and simultaneously can consider the insulation performance of the electrode assembly 10, the thickness of the electrode assembly 10 and the weight of the electrode assembly 10 to a certain extent, so that the safety of the battery cell 100, the volume energy density of the battery cell 100 and the mass energy density of the battery cell 100 can be considered to a certain extent while improving the use reliability of the battery cell 100.

In the above technical solution, at least one of the two ends of the first isolation film 13 in the winding direction exceeds the first pole piece 11 to form the first diaphragm portion 131, at least one of the two ends of the second isolation film 14 in the winding direction exceeds the first pole piece 11 to form the second diaphragm portion 141, the heat conducting member 15 is arranged between the first diaphragm portion 131 and the second diaphragm portion 141, and the heat conducting capability of the heat conducting member 15 is better than that of the first diaphragm portion 131 and the second diaphragm portion 141, so that the heat conducting member 15 can conduct the heat of the higher temperature part of the electrode assembly 10 to the lower temperature part of the electrode assembly 10, so as to reduce the difference between the highest temperature and the lowest temperature of the electrode assembly 10, improve the uniformity of the temperature distribution of the electrode assembly 10, reduce the risk of failure problems such as lithium precipitation of the electrode assembly 10, and improve the reliability of use of the electrode assembly 10; the arrangement of the heat conductive member 15 does not substantially affect the insulation properties of the first and second separator films 13 and 14, excessively increase the winding thickness of the electrode assembly 10, excessively increase the weight of the electrode assembly 10, and is convenient to simultaneously consider the safety of the electrode assembly 10 and the energy density of the battery cell 100.

It is apparent that even if at least one of the height of the electrode assembly 10 in the axial direction, the thickness of the electrode assembly 10, and the width of the electrode assembly 10 is greater than 150mm for the larger electrode assembly 10, the above-described technical scheme of the present application can improve the temperature distribution uniformity of the larger electrode assembly 10, so that the embodiments of the present application can better adapt to the increasingly larger volume requirements of the electrode assembly 10, thereby adapting to the increasingly larger capacity requirements of the battery cell 100, i.e., for the large-capacity battery cell 100, the risk of occurrence of reliability problems such as lithium precipitation due to temperature imbalance of the electrode assembly 10 can be reduced by adopting the electrode assembly 10 of the embodiment of the present application.

It will be appreciated that the heat conducting member 15 is disposed in an insulating manner with respect to the first pole piece 11, and in the embodiment of the present application, includes but is not limited to: when the heat conducting piece 15 is an electric conducting piece, the distance between the heat conducting piece 15 and the first pole piece 11 in the winding direction is larger than or equal to a preset distance, so that the heat conducting piece 15 and the first pole piece 11 are arranged in an insulating manner; when the heat conducting member 15 is an insulating member, the heat conducting member 15 and the first pole piece 11 are disposed at intervals in the winding direction, or the heat conducting member 15 and the first pole piece 11 are disposed closely to each other without a space therebetween.

It is understood that the length of the first diaphragm portion 131 and the length of the second diaphragm portion 141 may be specifically set as needed in the winding direction.

Optionally, the first substrate layer 132a and the second substrate layer 132b are made of the same material; and/or the thermal conductivity of the first base layer 132a is equal to the thermal conductivity of the second base layer 132 b. Of course, the first substrate layer 132a and the second substrate layer 132b are different in at least one of material and thermal conductivity.

In some embodiments of the present application, the thermal conductivity of the thermal conductive member 15 is greater than 10 times the thermal conductivity of the first diaphragm portion 131 and the second diaphragm portion 141, i.e., the thermal conductivity of the thermal conductive member 15 is greater than 10 times the thermal conductivity of the first diaphragm portion 131, and the thermal conductivity of the thermal conductive member 15 is greater than 10 times the thermal conductivity of the second diaphragm portion 141; and/or the thermal conductivity of the thermal conductive member 15 is greater than 10W/(m·k), for example, the thermal conductivity of the thermal conductive member 15 may be 34.8W/(m·k) (for example, the thermal conductive member 15 is a lead layer), 67W/(m·k) (for example, the thermal conductive member 15 is a tin layer), 80W/(m·k) (for example, the thermal conductive member 15 is a iron layer), 237W/(m·k) (for example, the thermal conductive member 15 is an aluminum layer), 317W/(m·k) (for example, the thermal conductive member 15 is a gold layer), 401W/(m·k) (for example, the thermal conductive member 15 is a copper layer), 429W/(m·k) (for example, the thermal conductive member 15 is a silver layer), 270W/(m·k) (for example, the thermal conductive member 15 is a silicon carbide layer), 310W/(m·k) (for example, aluminum nitride copper layer), 150W/(m·k) (for example, the thermal conductive member 15 is a graphite layer), 5000W/(m·k) (for example, the thermal conductive member 15 is a graphene layer, the thermal conductive member 15 is a graphene layer, and the thermal conductivity of 3000 to 5000W/(m·k)) and so on.

In the above technical solution, by setting the thermal conductivity of the thermal conductive member 15 to be greater than 10 times that of the first separator 131 and the second separator 141, and/or setting the thermal conductivity of the thermal conductive member 15 to be greater than 10W/(m·k), the thermal conductive member 15 can have significant thermal conductivity with respect to the first separator 131 and the second separator 141, and the thermal conductive member 15 has high thermal conductivity, so that the heat of the higher temperature portion of the electrode assembly 10 can be quickly conducted to the other lower temperature portions of the electrode assembly 10, which is beneficial to improving the timeliness and rapidity of the temperature on the electrode assembly 10 tending to be evenly distributed.

It is understood that when the thermal conductivity of the thermal conductive member 15 is greater than 10 times that of the first and second diaphragm portions 131 and 141, if the thermal conductivity of the first and second diaphragm portions 131 and 141 are not equal, the thermal conductivity of the thermal conductive member 15 may be greater than 10 times that of the first and second base layers 132a and 132b, which are better in thermal conductivity; that is, it is noted that one of the first base layer 132a and the second base layer 132b has a thermal conductivity of λ ₁, the other has a thermal conductivity of λ ₂,λ₁＞λ₂, and the thermal conductivity of the thermal conductive member 15 is greater than 10×λ ₁.

Illustratively, the first separator 13 and the second separator 14 are PE films (polyethylene films), and the thermal conductivity of the first separator 13 and the second separator 14 is approximately 0.3W/(m·k), in which case the thermal conductivity of the thermal conductive member 15 may be greater than 3W/(m·k); or the first separator 13 and the second separator 14 are PP films (polypropylene films), and the thermal conductivity of the first separator 13 and the second separator 14 is approximately 0.21 to 0.26W/(m·k), and the thermal conductivity of the thermal conductive member 15 may be greater than 2.6W/(m·k). For example, the heat conductive member 15 may further include a heat conductive silicone grease having a heat conductivity of 1.0 to 5.0W/(m·k).

In some embodiments of the present application, the heat conductive member 15 is an insulating member, and both end edges of the first separator part 131 are respectively flush with corresponding both end edges of the heat conductive member 15 in the axial direction of the electrode assembly 10, and both end edges of the second separator part 141 are respectively flush with corresponding both end edges of the heat conductive member 15; it can be seen that the height of the first and second separator parts 131 and 141 is equal to the height of the heat conductive member 15, respectively, in the axial direction of the electrode assembly 10.

Taking the axial direction of the electrode assembly 10 as the up-down direction as an example, the upper end edge of the first separator 131 is flush with the upper end edge of the heat conductive member 15, and the lower end edge of the first separator 131 is flush with the lower end edge of the heat conductive member 15; also, the upper end edge of the second diaphragm portion 141 is flush with the upper end edge of the heat conductive member 15, and the lower end edge of the second diaphragm portion 141 is flush with the lower end edge of the heat conductive member 15.

In the above technical solution, the heat conducting member 15 is an insulating member, and two end edges of the first diaphragm portion 131 and two end edges of the second diaphragm portion 141 are respectively flush with corresponding two end edges of the heat conducting member 15 in the axial direction of the electrode assembly 10, so that the heat conducting area of the heat conducting member 15 can be increased to a certain extent on the premise that the inside of the electrode assembly 10 is easy to generate short circuit by the heat conducting member 15, and the timeliness and rapidity that the temperature tends to be evenly distributed on the electrode assembly 10 are improved.

Referring to fig. 5, in some embodiments of the present application, the heat conducting member 15 is an electrically conductive member, in the axial direction of the electrode assembly 10, two end edges of the first separator 131 extend beyond corresponding two end edges of the heat conducting member 15, and two end edges of the second separator 141 extend beyond corresponding two end edges of the heat conducting member 15; it can be seen that the height of the first and second separator parts 131 and 141 is greater than the height of the heat conductive member 15 in the axial direction of the electrode assembly 10, such that both end edges of the heat conductive member 15 are spaced apart from the corresponding edges of the first separator part 131, and both end edges of the heat conductive member 15 are spaced apart from the corresponding edges of the second separator part 141, respectively.

Taking the axial direction of the electrode assembly 10 as an example, the upper end edge of the first diaphragm portion 131 extends to exceed the upper end edge of the heat conducting member 15, such that the upper end edge of the first diaphragm portion 131 is arranged above the upper end edge of the heat conducting member 15 at intervals, and the lower end edge of the first diaphragm portion 131 extends to exceed the lower end edge of the heat conducting member 15, such that the lower end edge of the first diaphragm portion 131 is arranged below the lower end edge of the heat conducting member 15 at intervals; also, the upper end edge of the second diaphragm portion 141 extends beyond the upper end edge of the heat conductive member 15 such that the upper end edge of the second diaphragm portion 141 is disposed above the upper end edge of the heat conductive member 15 at intervals, and the lower end edge of the second diaphragm portion 141 extends beyond the lower end edge of the heat conductive member 15 such that the lower end edge of the second diaphragm portion 141 is disposed below the lower end edge of the heat conductive member 15 at intervals.

In the above technical solution, through setting up in the axial direction of electrode assembly 10, the both ends border of first diaphragm portion 131 and the both ends border of second diaphragm portion 141 extend to respectively and surpass the corresponding both ends border of heat conduction spare 15 for there is certain interval respectively at the both ends border of heat conduction spare 15 and the corresponding both ends border of first diaphragm portion 131, and there is certain interval respectively at the both ends border of heat conduction spare 15 and the corresponding both ends border of second diaphragm portion 141, so that further reduction heat conduction spare 15 is to the influence of the insulating ability of first barrier film 13 and second barrier film 14, reduces the risk that electrode assembly 10 takes place the short circuit, is favorable to promoting the security of electrode assembly 10. That is, the above arrangement is convenient so that the electrode assembly 10 does not raise the risk of short circuit due to the arrangement of the heat conductive member 15.

In the embodiment of the present application, the axial direction of the electrode assembly 10 may be understood as the extending direction of the central axis of the electrode assembly 10, the winding direction of the electrode assembly 10 may be understood as the circumferential direction of the electrode assembly, and the winding direction of the electrode assembly 10 may be perpendicular to the axial direction of the electrode assembly 10.

Referring to fig. 5, in some embodiments of the present application, in the axial direction of the electrode assembly 10, a distance between the two end edges of the heat conducting member 15 and the corresponding two end edges of the first separator 131 is x, x is less than or equal to 20mm, and a distance between the two end edges of the heat conducting member 15 and the corresponding edges of the second separator 141 is y, y is less than or equal to 20mm. For example, x may be 20mm, 19mm, 18mm, 17mm, 16mm, 15mm, 14mm, 11.5mm, 9.5mm, or the like, and y may be 20mm, 19mm, 18mm, 16.5mm, 16mm, 15mm, 13.5mm, 11.5mm, 9mm, 8mm, or the like.

It can be understood that the interval between one end edge of the heat conductive member 15 and the corresponding edge of the first separator 131, the interval between the other end edge of the heat conductive member 15 and the corresponding edge of the first separator 131 are equal or unequal in the axial direction of the electrode assembly 10; also, in the axial direction of the electrode assembly 10, the interval between one end edge of the heat conductive member 15 and the corresponding edge of the second separator 141 is equal to or different from the interval between the other end edge of the heat conductive member 15 and the corresponding edge of the second separator 141. For example, taking the axial direction of the electrode assembly 10 as the up-down direction, the interval between the upper end edge of the heat conducting member 15 and the upper end edge of the first separator 131 is x1, the interval between the lower end edge of the heat conducting member 15 and the lower end edge of the first separator 131 is x2, x1 and x2 are less than or equal to 20mm, and x1 and x2 may be equal or unequal; also, the distance between the upper end edge of the heat conductive member 15 and the upper end edge of the second diaphragm portion 141 is y1, the distance between the lower end edge of the heat conductive member 15 and the lower end edge of the second diaphragm portion 141 is y2, y1 and y2 are each less than or equal to 20mm, and y1 and y2 may be equal or unequal.

In the above technical solution, the distance between the edges of the two ends of the heat conducting member 15 in the axial direction of the electrode assembly 10 and the corresponding edges of the first diaphragm portion 131 and the corresponding edges of the second diaphragm portion 141 is less than or equal to 20mm, so that the heat conducting member 15 is arranged to have both the heat conducting property and the heat conducting effect of the heat conducting member 15 on the premise of having both the insulating properties of the first insulating film 13 and the insulating property of the second insulating film 14, thereby facilitating both the insulating properties of the first insulating film 13 and the insulating film 14 and improving the temperature distribution of the electrode assembly 10.

Alternatively, in the axial direction of the electrode assembly 10, both end edges of the first separator part 131 are disposed flush with corresponding edges of the second separator part 141, respectively.

Further, 8 mm.ltoreq.x.ltoreq.12 mm, for example, x may be 8mm, 9mm, 10mm, 11mm, 12mm or the like; 8 mm.ltoreq.y.ltoreq.12 mm, for example y may be 8mm, 8.5mm, 10mm, 10.5mm, 12mm or the like. Thereby, it is convenient to make the arrangement of the heat conductive member 15 further better compatible with both the insulating properties of the first separator 13, the second separator 14 and the improvement of the temperature distribution of the electrode assembly 10.

Alternatively, in the winding direction of the electrode assembly 10, both end edges of the heat conductive member 15 may be disposed flush with the corresponding both end edges of the first separator 131, respectively, and both end edges of the heat conductive member 15 are disposed flush with the corresponding both end edges of the second separator 141, respectively; or in the winding direction of the electrode assembly 10, both end edges of the first separator part 131 extend beyond the corresponding both end edges of the heat conductive member 15, respectively, and both end edges of the second separator part 141 extend beyond the corresponding both end edges of the heat conductive member 15, respectively.

Referring to FIG. 4, in some embodiments of the present application, the thickness of the heat conducting member 15 is t.ltoreq.50 μm. For example, t may be 11 μm, 13 μm, 14 μm, 16 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, or the like.

In the above technical solution, the thickness t of the heat conducting member 15 is less than or equal to 50 μm, so that the heat conducting effect of the heat conducting member 15 is considered in the setting of the heat conducting member 15, and the winding thickness and the weight of the electrode assembly 10 are considered at the same time, thereby facilitating the improvement of the temperature distribution of the electrode assembly 10 and the volume energy density and the mass energy density of the battery cell at the same time.

Further, t.ltoreq.10.ltoreq.20 μm, for example, t may be 10 μm, 12 μm, 15 μm, 17 μm, 18 μm, 19 μm or 20 μm or the like. Thereby, it is convenient to make the arrangement of the heat conductive member 15 further better while improving the temperature distribution of the electrode assembly 10 and the energy density of the battery cell.

In some embodiments, the heat conducting member 15 is a non-phase change material member, so that the shape and volume of the heat conducting member 15 are basically unchanged after absorbing heat, thereby reducing the cost of the heat conducting member 15 and improving the stability of the heat conducting member 15.

In the above technical solution, by providing the heat conducting member 15 as a non-phase change material member (e.g., metal or nonmetal described later), the stability of the heat conducting member 15 is advantageously improved, so that the safety and reliability of the electrode assembly 10 are conveniently improved.

In some embodiments of the present application, the thermally conductive member 15 includes a metal layer and/or a non-metal layer.

In the above technical scheme, through setting up heat conduction spare 15 and including metal level and/or nonmetallic layer, be convenient for under the prerequisite of improving electrode assembly 10 temperature distribution, realize the nimble material selection of heat conduction spare 15, make things convenient for the setting of heat conduction spare 15, and be convenient for satisfy actual differentiation demand.

It is understood that when the heat conductive member 15 includes a metal layer and a non-metal layer, the metal layer and the non-metal layer may be stacked in the thickness direction of the separation film 13, and the number of the metal layers, the number of the non-metal layers, the stacking order of the metal layers and the non-metal layers, and the like may be specifically set according to actual needs.

Alternatively, when the heat conductive member 15 includes a metal layer, the coefficient of heat conductivity of the metal layer is greater than 10 times the coefficient of heat conductivity of the first diaphragm portion 131 and the second diaphragm portion 141, and/or the coefficient of heat conductivity of the metal layer is greater than 10W/(m·k); when the heat conductive member 15 includes a non-metal layer, the non-metal layer has a heat conductivity greater than 10 times that of the first diaphragm portion 131 and the second diaphragm portion 141, and/or the non-metal layer has a heat conductivity greater than 10W/(m·k).

Alternatively, when the heat conductive member 15 includes a metal layer, the metal layer may include metal powder so as to form and coat the metal layer.

In some embodiments, the metal layer comprises one or more of an aluminum layer, a copper layer, an iron layer, a silver layer, a gold layer, a tin layer, and a lead layer; the nonmetallic layer comprises one or more of a graphene layer, a graphite layer, an aluminum nitride layer, a silicon carbide layer and a thermally conductive silicone grease layer.

In the above technical solution, by providing the structures of the metal layer and the nonmetal layer, the heat conducting member 15 is convenient to have good heat conducting capability, so as to effectively improve the temperature distribution of the electrode assembly 10, and make the temperature distribution of the electrode assembly 10 more uniform.

It is to be understood that, when the metal layer includes a plurality of layers of aluminum layer, copper layer, iron layer, silver layer, gold layer, tin layer, and lead layer, the above-described multi-layer structure may be stacked in the thickness direction of the separator 13, and the stacking order of the multi-layer structure is not particularly limited in the embodiment of the present application. When the nonmetallic layer includes a plurality of layers of graphene layer, graphite layer, aluminum nitride layer, silicon carbide layer, and thermally conductive silicone grease layer, the multilayer structure may be stacked in the thickness direction of the isolation film 13, and the stacking order of the multilayer structure is not particularly limited in the embodiment of the present application.

Illustratively, the heat conducting member 15 is a copper layer, so that the heat conducting capability of the heat conducting member 15 is improved, the cost of the heat conducting member 15 is reduced, and the heat conducting member 15 has good stability.

In some embodiments of the present application, the heat conducting member 15 includes a metal layer and a non-metal layer, the metal layer is a plurality of layers, the metal layer is disposed between the non-metal layer and the first diaphragm portion 131, and the metal layer is also disposed between the non-metal layer and the second diaphragm portion 141.

It can be seen that the nonmetallic layer is one or more layers, the metal layers are multiple layers, two of the multiple layers are respectively a first metal layer and a second metal layer, the first diaphragm portion 131 is tightly attached to the first metal layer, the second diaphragm portion 141 is tightly attached to the second metal layer, and other metal layers except the first metal layer and the second metal layer, and all nonmetallic layers are arranged between the first metal layer and the second metal layer.

For example, the nonmetallic layer is one or more layers, the metal layers are two layers, the two metal layers are a first metal layer and a second metal layer respectively, the first diaphragm part 131 is tightly attached to the first metal layer, the second diaphragm part 141 is tightly attached to the second metal layer, and all nonmetallic layers are arranged between the first metal layer and the second metal layer; for example, the nonmetallic layer is a plurality of layers, the metal layers are three or more than three, wherein two metal layers are respectively a first metal layer and a second metal layer, the first diaphragm portion 131 is tightly attached to the first metal layer, the second diaphragm portion 141 is tightly attached to the second metal layer, and the rest of the metal layers and all nonmetallic layers are all arranged between the first metal layer and the second metal layer.

In the above technical solution, the thermal layer 132c includes a metal layer and a nonmetal layer, and the metal layer is disposed between the nonmetal layer and the first diaphragm portion 131 and between the nonmetal layer and the second diaphragm portion 141, so that the metal layer separates the first diaphragm portion 131 from the nonmetal layer and separates the second diaphragm portion 141 from the nonmetal layer, so that the metal layer and the nonmetal layer are disposed, which is beneficial to reducing the risk of falling off of the metal layer; if the metal layer comprises metal powder, the risk of metal powder falling off is reduced and the risk of metal leakage is reduced by sandwiching the metal layer between the corresponding membrane portion and the non-metal layer. In addition, because the metal layer is arranged between the corresponding diaphragm part and the nonmetal layer, the thickness of the metal layer and the thickness of the nonmetal layer are not easy to contact with the pole piece, the insulation setting of the metal layer is realized, and the normal use reliability of the electrode assembly 10 is improved.

Of course, in other embodiments, a non-metallic layer may be further disposed between the metallic layer and the first diaphragm portion 131, and/or a non-metallic layer may be further disposed between the metallic layer and the second diaphragm portion 141.

It will be appreciated that in embodiments of the present application, the first pole piece 11 may be an anode pole piece, or the first pole piece 11 may be a cathode pole piece. The electrode assembly 10 may further include a second electrode sheet 12, the polarity of the second electrode sheet 12 being opposite to the polarity of the first electrode sheet 11, the second electrode sheet 12, the first separator 13, the second separator 14 and the first electrode sheet 11 being stacked, the second electrode sheet 12 being disposed on a side of the first separator 13 facing away from the first electrode sheet 11, or the second electrode sheet 12 being disposed on a side of the second separator 14 facing away from the first electrode sheet 11.

In a second aspect, an embodiment of the present application provides a battery cell 100 including the electrode assembly 10 described above. For example, the battery cell 100 further includes a case 20, and the electrode assembly 10 described above is accommodated in the case 20.

In the above technical solution, the battery cell 100 adopts the above electrode assembly 10, and the temperature distribution on the electrode assembly 13 is relatively balanced, so that the reliability and safety of the use of the battery cell 100 can be improved, and the energy density of the battery cell 100 can be considered.

In a third aspect, an embodiment of the present application provides a battery 200, including the battery cell 100 described above.

In the above technical solution, since the battery 200 employs the battery cell 100, and the reliability and safety of the use of the battery cell 100 are improved, the reliability and safety of the use of the battery cell 100 can be improved.

In a fourth aspect, an embodiment of the present application provides an electric device 1000, including the battery 200 described above, where the battery 200 is used to provide electric energy.

In the above technical solution, the above battery 200 is adopted in the power consumption device 1000, and the reliability and safety of use of the battery 200 are good, so that the reliability and safety of use of the power consumption device 1000 are improved.

Referring again to fig. 4 and 5, an electrode assembly 10 according to an embodiment of the present application will be described. The following examples are illustrative only and are not to be construed as limiting the application.

The electrode assembly 10 is a wound electrode assembly, and the electrode assembly 10 includes a first electrode sheet 11, a second electrode sheet 12, a first separator 13, a second separator 14, and a heat conductive member 15.

In the winding direction of the electrode assembly 10, the length of the first electrode sheet 11 is substantially equal to the length of the second electrode sheet 12, the length of the first separator 13 is substantially equal to the length of the second separator 14, the first separator 13 includes a first separator portion 131 and a third separator portion 132, the second separator 14 includes a second separator portion 141 and a fourth separator portion 142, the first electrode sheet 11 is disposed between the third separator portion 132 and the fourth separator portion 142, and the second electrode sheet 12 is disposed on a side of the third separator portion 132 facing away from the first electrode sheet 11. Wherein, in the winding direction, the portions of the first isolation film 13, of which both ends respectively protrude from the first pole piece 11, are respectively formed as first diaphragm portions 131, and the portions of the second isolation film 141, of which both ends respectively protrude from the first pole piece 11, are respectively formed as second isolation films 141, that is, in the winding direction, both ends of the third diaphragm portion 132 are respectively provided with first diaphragm portions 131, and both ends of the fourth diaphragm portion 142 are respectively provided with second diaphragm portions 141.

The heat conducting member 15 may be a metal member, or the heat conducting member 15 may be a non-metal member; the thermal conductivity of the thermal conductive member 15 is greater than 10 times the thermal conductivity of the first and second separator films 13 and 14.

In the above technical solution, the heat conducting member 15 can conduct the heat of the higher temperature part of the electrode assembly 10 to the lower temperature part of the electrode assembly 10, so as to reduce the temperature difference of the electrode assembly 10, improve the temperature distribution uniformity of the electrode assembly 10, and reduce the highest temperature of the electrode assembly 10, thereby reducing the risk of failure problems such as lithium precipitation of the electrode assembly 10, and improving the use reliability; further, the winding thickness and the weight of the electrode assembly 10 are simultaneously compatible, without excessively reducing the energy density of the battery cell 100.

Next, temperature tests were performed on the electrode assembly 10 (including examples 1 to 5 below) and the electrode assembly (hereinafter referred to as comparative example) without the heat conductive member in the above examples, respectively, under the same conditions, and the test results are shown in table 1; the axial direction of the electrode assembly 10 is the up-down direction, the tab is located at the top of the electrode assembly 10, and the main heat generating position of the electrode assembly 10 is located at the tab during the cycling process.

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

The above is only a preferred embodiment of the present application, and is not intended to limit the present application, but various modifications and variations can be made to the present application by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. The utility model provides an electrode assembly, its characterized in that, electrode assembly is coiling formula electrode assembly and includes first pole piece, first barrier film, second barrier film and heat conduction spare, first pole piece is located between first barrier film and the second barrier film, in the coiling direction, at least one of the both ends of first barrier film surpasses first pole piece to form first diaphragm portion, at least one of the both ends of second barrier film surpasses first pole piece, in order to form second diaphragm portion, the heat conduction spare is located relative setting between first diaphragm portion and the second diaphragm portion, and with first diaphragm portion and the heat conduction cooperation respectively of second diaphragm portion, the coefficient of heat conduction spare is greater than first diaphragm portion and the coefficient of heat conduction of second diaphragm portion.

2. The electrode assembly of claim 1, wherein the electrode assembly comprises,

The thermal conductivity of the thermal conductive member is greater than 10 times the thermal conductivity of the first diaphragm portion and the second diaphragm portion; and/or the number of the groups of groups,

The heat conduction coefficient of the heat conduction member is more than 10W/(mK).

3. The electrode assembly according to claim 1, wherein the heat conductive member is an insulating member, and both end edges of the first separator portion and both end edges of the second separator portion are flush with corresponding both end edges of the heat conductive member, respectively, in an axial direction of the electrode assembly.

4. The electrode assembly according to claim 1, wherein the heat conductive member is an electrically conductive member, both end edges of the first separator portion extend beyond corresponding both end edges of the heat conductive member, respectively, and both end edges of the second separator portion extend beyond corresponding both end edges of the heat conductive member, respectively, in an axial direction of the electrode assembly.

5. The electrode assembly according to claim 4, wherein a distance between both end edges of the heat conductive member and corresponding edges of the first separator portion in an axial direction of the electrode assembly is x, x is 20mm or less, and a distance between both end edges of the heat conductive member and corresponding edges of the second separator portion is y, y is 20mm or less.

6. The electrode assembly of claim 5, wherein 8mm +.x +.12mm, 8mm +.y +.12mm.

7. The electrode assembly of claim 1, wherein the thermally conductive member has a thickness t, t being less than or equal to 50 μm.

8. The electrode assembly of claim 7, wherein the thermally conductive member has a thickness t,10 μm and t and 20 μm.

9. The electrode assembly of claim 1, wherein the thermally conductive member is a non-phase change material member.

10. The electrode assembly of any one of claims 1-9, wherein the thermally conductive member comprises a metallic layer and/or a non-metallic layer.

11. The electrode assembly of claim 10, wherein the metal layer comprises one or more of an aluminum layer, a copper layer, an iron layer, a silver layer, a gold layer, a tin layer, and a lead layer, and the non-metal layer comprises one or more of a graphene layer, a graphite layer, an aluminum nitride layer, a silicon carbide layer, and a thermally conductive silicone grease layer.

12. The electrode assembly according to claim 10, wherein the heat conductive member includes a metal layer and a non-metal layer, the metal layer being a plurality of layers, the metal layer being provided between the non-metal layer and the first separator portion, and between the non-metal layer and the second separator portion, respectively.

13. A battery cell characterized by comprising an electrode assembly according to any one of claims 1-12.

14. A battery comprising the battery cell according to claim 13.

15. An electrical device comprising a battery according to claim 14 for providing electrical energy.