CN213905449U

CN213905449U - Electrode assembly, battery cell, battery and device using battery

Info

Publication number: CN213905449U
Application number: CN202022763507.6U
Authority: CN
Inventors: 胡洋; 唐代春
Original assignee: Contemporary Amperex Technology Co Ltd
Current assignee: Contemporary Amperex Technology Co Ltd
Priority date: 2020-11-26
Filing date: 2020-11-26
Publication date: 2021-08-06
Anticipated expiration: 2030-11-26

Abstract

The embodiment of the application relates to the technical field of batteries, in particular to an electrode assembly, a battery monomer, a battery and a device using the battery. Wherein, electrode subassembly includes: the main body part comprises a positive pole piece and a negative pole piece, and the positive pole piece and the negative pole piece are wound or laminated to form the main body part; an insulating member including a base material and a bonding portion provided on an inner surface of the base material and used to bond the base material to the main body portion; wherein the projection area of the bonding part on the base material is smaller than the area of the base material. The application can effectively improve the local overheating phenomenon of the battery monomer in the using process, prolong the service life of the battery monomer, prevent the occurrence of thermal runaway and delay the speed of thermal spread.

Description

Electrode assembly, battery cell, battery and device using battery

Technical Field

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

Background

The insulating component in the electrode assembly generally functions as a fixed pole piece and insulation, and the common adhesive tape structure comprises a base material and a bonding layer, wherein the base material provides fixing and insulating protection performance, and the bonding layer ensures that the base material and the electrode assembly are firmly bonded. The puncture strength of the gummed paper is generally improved by increasing the thickness of the base material, and the bonding strength of the gummed paper is improved by increasing the area of the bonding layer.

However, the electrode assembly generates heat during use, and the use of the adhesive tape affects the heat transfer and dissipation, so that the battery is easily overheated locally during use, the service life of the battery cell is affected, and even thermal runaway and thermal spread are accelerated.

SUMMERY OF THE UTILITY MODEL

In view of the above problems, embodiments of the present application provide an electrode assembly, a battery cell, a battery, and a device using the battery, which can effectively improve a local overheating phenomenon of the battery cell during use, prevent occurrence of thermal runaway, and delay a thermal spreading rate.

In a first aspect of embodiments of the present application, there is provided an electrode assembly including:

the main body part comprises a positive pole piece and a negative pole piece, and the positive pole piece and the negative pole piece are wound or laminated to form the main body part;

an insulating member including a base material and a bonding portion provided on an inner surface of the base material and used to bond the base material to the main body portion;

wherein a projected area of the bonding portion on the base material is smaller than an area of the base material.

In some embodiments, the bonding portion includes a plurality of bonding units dispersed on the surface of the base material, and any adjacent two of the bonding units are spaced apart from each other.

In some embodiments, the projected area of each bonding unit on the surface of the substrate is a, the number of bonding units is N, and the area of the substrate is B; A. n, B satisfies the relationship: a multiplied by N/B is more than 0.15 and less than 0.25.

In some embodiments, the plurality of bonding elements are arrayed across the surface of the substrate.

In some embodiments, the projection shape of each bonding unit on the substrate is at least one of diamond, circle and square.

In some embodiments, the substrate is at least one of a silicone sheet, a rubber sheet, a plastic sheet, and a polymer resin sheet filled with a thermally conductive material.

In some embodiments, the thermally conductive material is at least one of a metal oxide, a metal carbide, a metal nitride.

In a second aspect of the embodiments of the present application, there is provided a battery cell, including a case and the electrode assembly in the above scheme; the housing is configured as a hollow cavity, and the electrode assembly is received within the cavity of the housing.

In some embodiments, the battery cell includes an electrode assembly, and the base material is attached to both surfaces of the main body portion in a thickness direction.

In some embodiments, the battery cell includes a plurality of electrode assemblies, the base material is located between the main body portion of the outermost electrode assembly and the cavity wall of the housing, and the base material is adhered to the surface of the main body portion of the outermost electrode assembly.

In a third aspect of the embodiments of the present application, a battery is provided, which includes the battery cell in the above aspect.

In a fourth aspect of the embodiments of the present application, there is provided an apparatus using a battery, including the battery in the above aspect.

According to the embodiment of the application, the coating area of the bonding part on the base material is reduced, so that heat generated by the main body part of the electrode assembly can be timely transmitted and dispersed among different parts of the same electrode assembly, among the electrode assembly, other components and the outside air, the performance reduction and even failure of the battery caused by local overheating are avoided, the service life of the battery is prolonged, thermal runaway of a battery monomer is prevented, and the occurrence of thermal spreading is delayed.

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 an exploded schematic view of a battery cell according to an embodiment of the present disclosure.

Fig. 2 is a schematic cross-sectional view of an electrode assembly according to an embodiment of the present disclosure.

Fig. 3 is an expanded view of an insulating member disclosed in an embodiment of the present application.

Fig. 4 is a schematic view of the projected shape of the bonding unit on the substrate.

Fig. 5 is a partially exploded view of an electrode assembly when the electrode assembly is accommodated in a case of a battery cell according to an embodiment of the present invention.

Fig. 6 is an exploded view of a plurality of electrode assemblies when the plurality of electrode assemblies are accommodated in a case of a battery cell according to an embodiment of the present disclosure.

Fig. 7 is another exploded view of a plurality of electrode assemblies when the plurality of electrode assemblies are accommodated in a case of a battery cell according to an embodiment of the present disclosure.

Fig. 8 is a schematic structural diagram of a battery according to an embodiment of the present application.

Fig. 9 is a schematic structural diagram of a battery module according to an embodiment of the present application.

Fig. 10 is a schematic structural diagram of an electric device according to an embodiment of the present application.

Description of reference numerals: 20. a housing; 40. an electrode assembly; 41. a main body portion; 411. a positive electrode plate; 412. a negative pole piece; 413. An isolation film; 414. a positive electrode tab; 415. a negative electrode tab; 42. an insulating member; 421. a substrate; 422. a bonding unit; 1. An end cap assembly; 11. an end cover plate; 12. an electrode terminal; 30. a current collecting member; s1, end face; s2, a side surface; s3, bottom surface; s4, a top surface; 200. a battery; 300. a battery module; 201. a first case; 202. a second case; 210. a controller; 220. a motor.

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 presented with the directional terms as they are used in the drawings and not intended to limit the specific structure of the 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 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 200 pack is in the position shown in the drawings, when these positions are changed, these directions should be interpreted differently to correspond to the changes.

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.

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. The present application is described in further detail below with reference to specific embodiments and with reference to the attached drawings.

Fig. 1 is a schematic diagram of a partially exploded structure of a battery cell according to an embodiment of the present disclosure, wherein the battery cell may be a secondary battery or a primary battery, such as, but not limited to, a lithium ion secondary battery, a lithium ion primary battery, a lithium sulfur battery, a sodium lithium ion battery, or a magnesium ion battery. The battery cell can be in a cylinder, a flat body, a cuboid or other shapes. In another embodiment of the present application, a plurality of battery cells may be stacked together, for example, the plurality of battery cells may be connected in series, in parallel, or in series-parallel to form a battery module or a battery pack, where the series-parallel refers to a combination of series connection and parallel connection. For the sake of brevity, the battery module or the battery pack may be referred to as a battery 200 in the present application.

The battery cell includes a case and one or more electrode assemblies 40 disposed within the case.

As shown in fig. 2, the electrode assembly 40 includes a main body portion 41 and an insulating member 42, wherein the main body portion 41 is formed by winding or stacking a first pole piece, a second pole piece, and a separation film 413 between the adjacent first pole piece and the second pole piece, which is illustrated in fig. 2 by taking the winding as an example; the isolation film 413 is an insulator between adjacent first and second pole pieces. In this embodiment, the first pole piece is exemplarily described as the positive pole piece 411, and the second pole piece is the negative pole piece 412. The positive active material is coated on the coated region of the positive electrode tab 411, and the negative active material is coated on the coated region of the negative electrode tab 412. A plurality of uncoated regions extending from the coated region of the body portion 41 are laminated as tabs. As shown in fig. 1, each electrode assembly 40 includes two tabs, i.e., a positive tab 414 and a negative tab 415. A positive tab 414 extends from the coated area of the positive pole piece 411 and a negative tab 415 extends from the coated area of the negative pole piece 412.

In the prior art, the insulating member 42 includes a base material 421 and an adhesive portion, for example, the base material 421 may be a polymer sheet made of one or more of polyethylene, polypropylene, polyethylene terephthalate, polyamide and aramid, the adhesive portion may be a polymer adhesive such as acrylic, epoxy, polyurethane, amino resin, phenolic resin, etc., and the adhesive portion is generally adhered to the inner surface of the base material 421 by painting or spraying, so as to enable the base material 421 to be adhered to the main body portion 41, fix the positive electrode sheet 411, the negative electrode sheet 412 and the isolation film 413 at the end, and insulate the electrode assembly 40 from the housing. The inner surface of the base 421 is a surface of the base 421 which is in direct contact with the main body 41.

The case includes the end cap assembly 1 and the case 20, the case is a hollow cavity, the case 20 is determined according to the shape of one or more electrode assemblies 40 after being assembled, for example, the case 20 may be a hollow rectangular parallelepiped, a hollow cube or a hollow cylinder, one face of the case 20 has an opening, i.e., a plane having no wall of the case 20 so that the case 20 communicates inside and outside, so that the electrode assemblies 40 can be accommodated in the case 20, the end cap assembly 1 is combined with the case 20 at the opening of the case 20 to form a hollow cavity, and after the electrode assemblies 40 are placed in the case, the case is filled with electrolyte and sealed. The housing 20 may be made of a metal material or plastic, alternatively, the housing 20 is made of aluminum or an aluminum alloy.

The end cap assembly 1 includes an end cap plate 11, two electrode terminals 12, and a pressure relief mechanism 13, wherein the end cap plate 11 is substantially in a flat plate shape, the end cap plate 11 is combined with the case 20 at an opening of the case 20 and covers the opening of the case 20, for example, the end cap plate 11 may be a metal plate and is connected to the case 20 by welding, so as to seal the electrode assembly 40 in the case 20, and the pressure relief mechanism 13 is used for relieving high-temperature and high-pressure emissions generated by thermal runaway inside the electrode assembly 40.

The two electrode terminals 12 are a positive electrode terminal and a negative electrode terminal, respectively, one current collecting member 30 is disposed corresponding to each electrode terminal 12, and the current collecting member 30 is located between the end cap plate 11 and the electrode assembly 40. Respectively for connecting the positive tab 414 and the positive terminal, and the negative tab 415 and the negative terminal.

During operation of the battery 200, heat is generated inside the electrode assembly 40, and the heat is released outward via the outer surface of the electrode assembly 40. As shown in fig. 1, in an embodiment, the outer surface of the electrode assembly 40 may include two end surfaces S1, two side surfaces S2, a bottom surface S3, and a top surface S4, wherein the two end surfaces S1 refer to two large surfaces substantially perpendicular to the thickness direction Y of the electrode assembly 40 in fig. 1, the two side surfaces S2 refer to arc surfaces positioned at both sides of the length direction X of the electrode assembly 40 in fig. 1, and the top surface S4 and the bottom surface S3 are respectively positioned at both ends of the electrode assembly 40 in the height direction Z.

When the insulating member 42 is attached to the surface of the main body portion 41, since the conventional base material 421 itself has poor heat conductivity, and, in order to enhance the bonding ability between the base material 421 and the main body portion 41, the base material 421 is entirely coated with a bonding portion having the same poor heat conductivity, so that it is difficult for heat generated inside the electrode assembly 40 to be uniformly dispersed and discharged outward through the surface, thereby making it easy for the electrode assembly 40 to be locally overheated, reducing the usability of the battery 200, and causing the battery 200 to fail. In addition, when thermal runaway occurs in one of the battery cells, since heat in the battery cell is difficult to dissipate through the surface, the temperature of the battery cell adjacent to the battery cell is rapidly increased, the thermal runaway rapidly spreads, and finally explosion may be initiated.

In order to solve the above problems, as shown in fig. 2 and 3, in the electrode assembly 40 disclosed in the present application, the projected area of the bonding portion on the substrate 421 is smaller than the area of the substrate 421, that is, in the coverage area of the substrate 421, the position of the main body portion 41 corresponding to the bonding portion is in contact with the bonding portion, the position of the main body portion 41 corresponding to the other position of the bonding portion is in direct contact with the substrate 421, and the thickness of the insulating member 42 covering the main body portion 41 at the position of the main body portion 41 in direct contact with the bonding portion is smaller, so that the heat in the main body portion 41 can be dissipated from the corresponding surface of the insulating member 42, the heat dissipation performance of the electrode assembly 40 is improved, the local overheating occurring in the use process of the electrode assembly 40 is prevented from affecting the use performance of the battery 200, the occurrence of thermal runaway is prevented to a certain extent, and the speed of thermal spreading is delayed.

In order to further ensure the dissipation of heat in the electrode assembly 40, an insulating sheet with good thermal conductivity is used as the base material 421, for example, the base material 421 is made of a thermal conductive insulating material, wherein the thermal conductive insulating material may be at least one of a silicone sheet, a rubber sheet, a plastic sheet, and a polymer resin sheet filled with a thermal conductive material, and the thermal conductive material is at least one of a metal oxide, a metal carbide, and a metal nitride, for example, thermal conductive powder such as nano silicon carbide, nano titanium nitride, nano aluminum oxide, and nano aluminum nitride.

At the position where the main body portion 41 contacts the base material 421, the heat generated by the main body portion 41 is directly radiated out through the base material 421, so that the heat transfer efficiency is further increased, and the electrode assembly 40 has better heat dissipation performance.

In fig. 3, in order to achieve firm adhesion of the adhesion portion to the base 421 without completely covering the base 421 and ensure the adhesion strength between the base 421 and the main body 41, in some embodiments, the adhesion portion includes a plurality of adhesion units 422 dispersed on the surface of the base 421, the adhesion units 422 may be formed by a dispensing process, and any two adjacent adhesion units 422 of the adhesion units 422 are disposed at intervals. Optionally, a plurality of bonding units 422 are distributed on the surface of the substrate 421 in an array, so as to ensure that the substrate 421 is firmly bonded to the main body 41 and each position thereof is subjected to a relatively uniform bonding force.

As shown in fig. 4, in some embodiments, the projection shape of each bonding unit 422 on the substrate 421 is at least one of a diamond shape, a circle shape and a square shape, i.e., the projection shapes of the bonding units 422 on the substrate 421 are the same, and are all one of the above shapes; alternatively, there are a plurality of projection shapes of the respective bonding units 422 on the base 421, at least one of which is included in the above shapes, and the projection shapes of the remaining bonding units 422 on the base 421 may be included in the above shapes, or may be any other shapes as long as it is ensured that the respective bonding units 422 are separated from each other.

The coverage of the bonding portion on the base material 421 affects not only the heat dissipation performance of the electrode assembly 40, but also the bonding strength between the base material 421 and the main body portion 41, and therefore, the selection of the coverage of the bonding portion is particularly critical, and the coverage of the bonding portion on the surface of the base material 421 is selected in the following specific tests.

Taking an example where the bonding portion is composed of a plurality of bonding units having the same projected area on the base 421, defining the area of the base 421 as B, the projected area of the single bonding unit 422 on the surface of the base 421 as a, and the number of bonding units as N, the coverage of the bonding portion on the surface of the base 421 is a × N/B.

Example 1:

electrode assemblies 40 were fabricated from insulating members 42 having an ax N/B of 0.10, and electrode assemblies 40 were mated pair-wise to produce finished hard-shell cells containing 4 electrode assemblies 40. The cathode of the battery core is made of a 5-series NCM ternary material, and the anode is made of an artificial quick-charging graphite material.

Example 2:

electrode assemblies 40 were fabricated from insulating member 42 having an ax N/B of 0.15, and electrode assemblies 40 were mated pair-wise to produce finished hard-shell cells containing 4 electrode assemblies 40. The cathode of the battery core is made of a 5-series NCM ternary material, and the anode is made of an artificial quick-charging graphite material.

Example 3:

electrode assemblies 40 were fabricated from insulating member 42 having an ax N/B of 0.20, and electrode assemblies 40 were mated pair-wise to produce finished hard-shell cells containing 4 electrode assemblies 40. The cathode of the battery core is made of a 5-series NCM ternary material, and the anode is made of an artificial quick-charging graphite material.

Example 4:

electrode assemblies 40 were fabricated from insulating member 42 having an ax N/B of 0.25, and electrode assemblies 40 were mated pair-wise to produce finished hard-shell cells containing 4 electrode assemblies 40. The cathode of the battery core is made of a 5-series NCM ternary material, and the anode is made of an artificial quick-charging graphite material.

Example 5:

electrode assemblies 40 were fabricated from insulating member 42 having an ax N/B of 0.30, and electrode assemblies 40 were mated pair-wise to produce finished hard-shell cells containing 4 electrode assemblies 40. The cathode of the battery core is made of a 5-series NCM ternary material, and the anode is made of an artificial quick-charging graphite material.

Comparative example:

electrode assemblies 40 were fabricated from prior art insulating members 42 and electrode assemblies 40 were mated pair-wise to produce a finished hard-shell cell containing 4 electrode assemblies 40. The cathode of the battery core is made of a 5-series NCM ternary material, and the anode is made of an artificial quick-charging graphite material.

The insulating member 42 used in the above 5 examples and comparative examples was subjected to a bond strength test by the following method: sticking adhesive paper with the length of 125mm and the width of 25mm on a stainless steel plate with the length of 125mm, the width of 50mm and the thickness of 1.1mm, rolling for 3 times by using a rubber compression roller with the weight of 2000g, standing for 20 min-40 min at the temperature of 23 ℃ and under the humidity of 50%, fixing the stainless steel plate on a tensile machine, stretching an adhesive paper sample at the constant speed of 300mm/min and the clamping distance of 40mm, recording the numerical value of the tensile machine when the adhesive paper is broken, and converting the numerical value into N/mm, namely the adhesive strength of the adhesive paper. The test results are reported in table 1 below.

TABLE 1

Group of

Example 1

Example 2

Example 3

Example 4

Example 5

Comparative example

Adhesive strength

0.08N/mm

0.12N/mm

0.13N/mm

As is clear from the data in table 1, the adhesive strength of the insulating member 42 in examples 2 to 5 can be substantially leveled with that of the comparative example, and it can be reasonably inferred that the adhesive strength requirement for the insulating member 42 can be satisfied when the coverage of the adhesive portion a × N/B > 0.15.

The bond strength in example 1 was much less than that of the comparative example and other examples and was unsatisfactory, and therefore was not considered in the following tests.

The insulating members 42 in the above examples 2, 3, 4, 5 and comparative example were subjected to a test for improving the cell thermal uniformity performance by: the temperature changes at the end face S1 and the side face S2 of the middle electrode assembly 40 after 3C high rate discharge from the fully charged state to the cutoff voltage at 25C for the finished hard shell cells of example 2, example 3, example 4, example 5, and the comparative example, respectively, are recorded in table 2 below.

TABLE 2

As can be seen from the data in table 2, the temperature difference between the center of the end surface S1 and the side surface S2 of the electrode assembly 40 in examples 2, 3, 4 and 5 is smaller than the temperature difference between the center of the end surface S1 and the side surface S2 of the electrode assembly 40 in the comparative example after the same discharge process and the same standing time, which indicates that the use of the improved insulating member 42 of the present application can improve the thermal uniformity of the electrode assembly 40 and prevent the electrode assembly 40 from being locally overheated. Moreover, as can be seen from the data in table 2, the temperature of the end surface S1 and the side surface S2 of the electrode assembly 40 in example 2, example 3, example 4 and example 5 decreased faster than the comparative example after the same discharge process, which indicates that the improved insulating member 42 of the present application can increase the heat dissipation rate of the electrode assembly 40 and improve the heat dissipation performance of the electrode assembly 40.

The above-described two improving effects are gradually evident from example 5 to example 2, and the difference between example 5 and comparative example is small, so that it is possible to reasonably disregard the case where the coverage rate a × N/B of the bonding portion is not less than 0.30, that is, when the coverage rate a × N/B of the bonding portion is less than 0.25, the thermal uniformity and the heat dissipation performance of the electrode assembly 40 can be remarkably improved.

Combining the two tests, the preferred range of coverage of the bond is 0.15 < A N/B < 0.25.

In order to further verify the conclusion of the embodiment of the present application, the tests for prolonging the service life of the battery cell and the test for delaying the thermal diffusion are continued in embodiments 2 and 4.

The test method for prolonging the service life of the battery cell comprises the following steps: the example 2, example 4 and comparative example cells were subjected to cycle tests (cell capacity 150Ah, after charging to 4.3V at 150A, discharging to 2.8V at 150A, and so forth) at constant temperatures of 25 ℃ and 45 ℃ respectively until the capacity retention rate decayed to 80%, and the total number of cycles was recorded, and the experimental data are described in table 3 below.

TABLE 3

Group of	Cycle life at 25 DEG C	Cycle life at 45 DEG C
			Example 2	3013 Ring	1845 Ring
Example 4	2987 ring	1854 circles
			Comparative example	2645 circles	1529 round (A)

As can be seen from the data recorded in table 3, the cycle lives of the battery cells of examples 2 and 4 were significantly longer than those of the comparative examples, which further illustrates that the electrode assembly using the insulating member of the example of the present application can prevent the occurrence of side reactions due to local overheating, improve the cycle performance of the battery cell, and thus prolong the service life of the battery. From the test data of examples 2 and 4, it can be reasonably concluded that the effect of prolonging the battery life can be achieved when the coverage of the adhesive portion is smaller than that of the comparative example, for example, the value range is 0.15 < A × N/B < 0.25.

The test method for retarding the thermal diffusion is as follows: the battery packs of the plurality of battery cells of the embodiment 2, the embodiment 4 and the comparative example are respectively formed, a certain battery cell is thermally out of control by heating, timing is started, and the time required by the adjacent battery cells of the out-of-control battery cell to generate thermal out-of-control is counted. The test results are reported in table 4 below,

TABLE 4

As can be seen from the data recorded in table 4, in example 2 and example 4, when thermal runaway occurred in a certain cell, the time required for thermal runaway to occur in the adjacent cells was longer than that in the comparative example, and it can be reasonably inferred that the effect of delaying thermal spread at the time of thermal runaway could be achieved in both cases where the coverage at the adhesion portion was smaller than that in the comparative example, 0.15 < a × N/B < 0.25, for example.

In summary, in the electrode assembly 40 of the embodiment of the present invention, by reducing the coating area of the bonding portion on the base material 421, the heat generated by the main body portion 41 of the electrode assembly 40 can be timely transmitted and dispersed between different portions of the same electrode assembly 40, between the electrode assembly 40 and the electrode assembly 40, between the electrode assembly 40 and other components, and between the electrode assembly 40 and the external air through the surface of the electrode assembly 40, so that the performance degradation and even the failure of the battery 200 caused by local overheating can be avoided, the service life of the battery 200 can be prolonged, the thermal runaway of the battery cell can be prevented, and the occurrence of thermal spreading can be delayed.

Another embodiment of the present application discloses a battery cell using the electrode assembly 40 of the above embodiment, the battery cell including the electrode assembly 40 of the above aspect and a case; the case is configured as a hollow cavity, and the electrode assembly 40 is received in the cavity of the case. The battery cell may include one electrode assembly 40 or may include a plurality of electrode assemblies 40.

As shown in fig. 5, in one embodiment, when one electrode assembly 40 is accommodated in the case, the base material 421 is adhered to both surfaces of the main body portion 41 in the thickness direction, and the base material 421 not only can fix the main body portion 41, but also can protect the main body portion 41, so as to prevent the metal foreign matter remaining on the end surface S1S1 of the electrode assembly 40 from pressing the case with the expansion of the electrode assembly 40 in the thickness direction during the operation of the electrode assembly 40 during the assembly of the battery cell, and further puncture the separation film 413 of the electrode assembly 40, so that the pole piece of the electrode assembly 40 is communicated with the case 20, thereby causing a short circuit and causing a safety risk.

As shown in fig. 6 and 7, in another embodiment, when a plurality of electrode assemblies 40 are accommodated in the case, for example, the electrode assemblies 40 are arranged side by side in the thickness direction, at this time, the base material 421 is located at least between the main body portion 41 of the outermost electrode assembly 40 and the cavity wall of the case, and the base material 421 is pasted on the surface of the main body portion 41 of the outermost electrode assembly 40, that is, the base material 421 may be located only between the main body portion 41 of the outermost electrode assembly 40 and the cavity wall of the case, as shown in fig. 6; alternatively, the base material is located not only between the main body portion 41 of the outermost electrode assembly 40 and the cavity wall of the case, but also between two adjacent main body portions. Both of the above two methods can prevent the metal foreign matter from piercing the isolation film 413 of the outermost electrode assembly 40, so that the pole piece of the electrode assembly 40 is communicated with the case 20, which causes short circuit and safety risk.

The battery cell in the above embodiment uses the improved electrode assembly 40, so that the battery cell also has the beneficial effects of avoiding performance degradation or even failure of the battery 200 caused by local overheating, prolonging the service life of the battery 200, preventing thermal runaway of the battery cell, delaying occurrence of thermal spread, and simultaneously effectively preventing safety risk caused by short circuit.

As shown in fig. 8, which is a schematic structural diagram of a battery 200 according to another embodiment of the present disclosure, the battery 200 includes a first case 201, a second case 202, and a plurality of battery modules 300, wherein the first case 201 and the second case 202 are fastened to each other, and the plurality of battery modules 300 are arranged in a space enclosed by the first case 201 and the second case 202. In some embodiments, the first case 201 and the second case 202 are hermetically connected.

As shown in fig. 9, the battery module 300 includes a plurality of battery cells, the battery cells can be vertically placed, the height direction of the battery cells is consistent with the vertical direction, and the plurality of battery cells are arranged side by side along the width direction; alternatively, the battery cells may be laid flat, the width direction of the battery cells may be identical to the vertical direction, and the plurality of battery cells may be stacked in at least one layer along the width direction, each layer including a plurality of battery cells arranged in the length direction.

In another embodiment of the present application, a plurality of batteries 200 are connected to each other to form a battery pack for supplying power to the electric device according to the power demand of the electric device. In another embodiment of the present application, the battery pack may be housed in a case and packaged. For the sake of brevity, the following embodiments are described taking the example in which the electric device includes the battery 200.

As shown in fig. 10, which is a schematic structural diagram of an electric device according to an embodiment of the present application, the electric device may be an automobile, the automobile 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. The automobile 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. 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, instead of or in part replacing fuel or natural gas to provide driving power for the automobile.

Those skilled in the art will appreciate that while some embodiments herein include some features included in other embodiments, rather than others, combinations of features of different embodiments are meant to be within the scope of the application and form different embodiments. 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. An electrode assembly, comprising:

the battery pack comprises a main body part (41), wherein the main body part (41) comprises a positive pole piece (411) and a negative pole piece (412), and the main body part (41) is formed by winding or laminating the positive pole piece (411) and the negative pole piece (412);

an insulating member (42), the insulating member (42) including a base material (421) and an adhesive portion provided on an inner surface of the base material (421) for adhering the base material (421) to the main body portion (41);

wherein a projected area of the bonding portion on the base material (421) is smaller than an area of the base material (421).

2. The electrode assembly according to claim 1, wherein the bonding portion comprises a plurality of bonding units (422) dispersed on the surface of the base material (421), and any adjacent two of the bonding units (422) among the plurality of bonding units (422) are disposed at intervals.

3. The electrode assembly of claim 2, wherein the projected area of each bonding unit (422) on the surface of the base material (421) is A, the number of bonding units (422) is N, and the area of the base material (421) is B;

A. n, B satisfies the relationship: a multiplied by N/B is more than 0.15 and less than 0.25.

4. The electrode assembly of claim 2, wherein the plurality of bonding units (422) are distributed in an array on the surface of the base material (421).

5. The electrode assembly of claim 2, wherein the projection shape of each bonding unit (422) on the base material (421) is at least one of diamond, circle and square.

6. The electrode assembly according to any of claims 1 to 5, wherein the base material (421) is made of a thermally conductive and insulating material.

7. A battery cell, comprising a housing and an electrode assembly (40) according to any one of claims 1-6; the shell comprises a shell (20) and an end cover assembly (1), wherein the shell (20) is constructed into a hollow cavity, an opening is formed in one side of the shell (20), the electrode assembly (40) is contained in the cavity of the shell (20), and the end cover assembly (1) is sealed and covered on the opening.

8. The battery cell according to claim 7, wherein the battery cell comprises an electrode assembly (40), and the base material (421) is attached to both surfaces of the main body portion (41) in the thickness direction.

9. The battery cell according to claim 7, wherein the battery cell comprises a plurality of electrode assemblies (40), the base material (421) is located between the main body part (41) of the outermost electrode assembly (40) and the side wall of the case (20), and the base material (421) is pasted on the surface of the main body part (41) of the outermost electrode assembly (40).

10. A battery comprising the battery cell of any one of claims 7-9.

11. A device for using a battery, characterized in that it comprises a battery (200) according to claim 10.