CN114467223A

CN114467223A - Electrode assembly, electrochemical device and electric equipment

Info

Publication number: CN114467223A
Application number: CN202180005607.7A
Authority: CN
Inventors: 彭涛; 杨新
Original assignee: Ningde Amperex Technology Ltd
Current assignee: Ningde Amperex Technology Ltd
Priority date: 2021-03-31
Filing date: 2021-03-31
Publication date: 2022-05-10
Also published as: WO2022205141A1

Abstract

The application discloses electrode assembly can use in the electrochemical device of consumer, and this electrode assembly includes pole piece subassembly, first conducting strip and second conducting strip, and first conducting strip includes: the electrode plate comprises a first non-bending part connected with the electrode plate assembly, a first bending part connected with the first non-bending part, and a second non-bending part connected with the first bending part, wherein the second non-bending part comprises a first area connected with the second conducting strip. The utility model provides an electrode assembly because first conducting strip only has once buckling, does not have the bounce-back that many times of buckling brought, consequently first conducting strip is difficult to the bounce-back, has effectively reduced the degree of difficulty that the shell was gone into to electrode assembly packing, has promoted electrochemical device's use reliability and security greatly.

Description

Electrode assembly, electrochemical device and electric equipment

Technical Field

The present disclosure relates to energy storage technologies, and particularly to an electrode assembly, an electrochemical device, and an electrical apparatus.

Background

Lithium ion batteries have many advantages of large volumetric and mass energy density, long cycle life, high nominal voltage, low self-discharge rate, small volume, light weight, etc., and have wide applications in the consumer electronics field. The electrode assembly in a lithium ion battery has a tab connected to a current collector, and the tab is usually assembled or connected by a transfer welding process or a conductive adhesive bonding process to form a tab finally extending out of a package case. In order to save the head space of the packaged electrode assembly and improve the volume energy density of the electrode assembly, the welding structure or the bonding structure of the tabs needs to be bent to form a bending structure, so that the volume is reduced to the maximum. However, the existing electrode assembly has large stress at the bent position, particularly the electrode assembly with a multi-tab structure, so that the bent structure is easy to rebound, and the use reliability and safety of the electrochemical device are affected.

Disclosure of Invention

The embodiment of the application provides an electrode assembly, an electrochemical device and electric equipment, and can solve the problem that a tab bending structure is easy to rebound.

In order to solve the above technical problem, in a first aspect, an embodiment of the present application provides an electrode assembly, including: the electrode plate assembly comprises a pole plate assembly, a first conducting plate and a second conducting plate;

the first conductive sheet includes: the electrode plate comprises a first non-bending part connected with the electrode plate assembly, a first bending part connected with the first non-bending part, and a second non-bending part connected with the first bending part, wherein the second non-bending part comprises a first area connected with the second conducting strip.

In some embodiments, the second conductive sheet comprises: a third non-bending portion connected to the second non-bending portion, a second bending portion connected to the third non-bending portion, and a fourth non-bending portion connected to the second bending portion.

In some embodiments, the first bending portion and the second bending portion are located on the same side of the first region along a thickness direction of the pole piece assembly.

In some embodiments, the first bending portion has a bending angle α, and α ≦ 80 ≦ 100 °.

In some embodiments, the length of the second non-bent portion is less than the thickness of the pole piece assembly.

In some embodiments, the surface of the first bending part is provided with an insulating member.

In some embodiments, an insulator is disposed between the second non-bent portion and the pole piece assembly.

In some embodiments, the second bend has a bend angle β, and 80 ≦ β ≦ 100 °.

In some embodiments, the third non-bending portion includes a second region connected to the first region, and a surface of the second region is provided with an insulating member.

In some embodiments, a surface of the fourth non-bent portion is provided with tab glue.

In some embodiments, the first conductive sheet is integrally formed.

In some embodiments, the second conductive sheet is integrally formed.

In some embodiments, the pole piece assembly comprises at least one of a wound structure or a laminated structure.

In some embodiments, the electrode assembly includes a plurality of the first conductive sheets connected by a plurality of the second non-bent portions.

In order to solve the above technical problem, in a second aspect, an embodiment of the present application provides an electrochemical device, including: an electrode assembly as described in the first aspect above.

In some embodiments, the electrochemical device further comprises:

the packaging shell comprises a containing groove, and the pole piece assembly, the first non-bending part, the first bending part, the second non-bending part, the third non-bending part and the second bending part in the electrode assembly are contained in the containing groove;

the second conducting strip further comprises an extending part located outside the packaging shell, and the extending part is connected with the fourth non-bending part.

In order to solve the above technical problem, in a third aspect, an embodiment of the present application provides an electrical device, including: the electrochemical device according to the second aspect described above.

Compared with the prior art, the beneficial effects of this application are: be different from prior art's condition, the electrode assembly that this application provided does not have the bounce-back that original bending for a plurality of times brought because first conducting strip only exists once buckling, consequently first conducting strip is difficult to bounce-back, has effectively reduced the degree of difficulty that the shell was gone into to electrode assembly packing, has promoted electrochemical device's use reliability and security greatly.

Drawings

The embodiments are illustrated by the figures of the accompanying drawings which correspond and are not meant to limit the embodiments, in which elements/blocks having the same reference number designation may be represented by like elements/blocks, and in which the drawings are not to scale unless otherwise specified.

FIG. 1 is a schematic side view of an electrode assembly according to an embodiment of the present disclosure;

FIG. 2 is a schematic side view of another electrode assembly provided in an embodiment of the present application;

FIG. 3 is a schematic structural diagram of an electrochemical device according to an embodiment of the present disclosure;

FIG. 4 is a schematic view of another embodiment of an electrochemical device according to the present disclosure;

fig. 5 is a schematic structural diagram of an electric device according to an embodiment of the present application.

Detailed Description

The present application will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the present application, but are not intended to limit the present application in any way. It should be noted that various changes and modifications can be made by one skilled in the art without departing from the spirit of the application. All falling within the scope of protection of the present application.

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

It should be noted that, if not conflicting, the individual features of the embodiments of the present application may be combined with each other within the scope of protection of the present application. In addition, although the functional blocks are divided in the device diagram, in some cases, the blocks may be divided differently from those in the device. Further, the terms "first," "second," "third," and the like, as used herein, do not limit the data and the execution order, but merely distinguish the same items or similar items having substantially the same functions and actions. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may be present.

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 present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

In addition, the technical features mentioned in the embodiments of the present application described below may be combined with each other as long as they do not conflict with each other.

In order to solve the problems that the bending structure of the current tab structure battery is easy to rebound, the use reliability and safety of an electrochemical device are affected, the embodiment of the application provides an electrode assembly, the tab structure which is bent for multiple times in the traditional process is replaced by a mode of bending a tab for one time, the rebound force/stress of bending for two times or more can be effectively eliminated, on one hand, the situation that gummed paper wrapped outside the electrode assembly falls off and is exposed is reduced, on the other hand, the shell entering difficulty of the electrode assembly can be reduced, the head space of a packaging shell is released, the volume energy density of the electrochemical device is improved, the problems that the tab is inserted backwards and the like due to the fact that the head space is too small can be reduced, and the reliability and safety of the electrochemical device are greatly improved.

Specifically, the embodiments of the present application will be further explained below with reference to the drawings.

A first aspect of the embodiments of the present application provides an electrode assembly, please refer to fig. 1, which illustrates a side view structure of an electrode assembly provided by an embodiment of the present application, where the electrode assembly 100 includes: a pole piece assembly 110, a first conductive sheet 120, and a second conductive sheet 130.

The first conductive sheet 120 includes: the electrode assembly comprises a first non-bent portion 121 connected to the electrode assembly 110, a first bent portion 122 connected to the first non-bent portion 121, and a second non-bent portion 123 connected to the first bent portion 122, wherein the second non-bent portion 123 includes a first region 1230 connected to the second conductive sheet 130. The electrode assembly that this application embodiment provided only needs first conducting strip 120 once to buckle, and the bounce-back that is brought by buckling is less, does benefit to electrode assembly 100's installation is favorable to reducing the headroom simultaneously, promotes electrochemical device's volume energy density, and reducible utmost point ear that leads to because of the headroom undersize inserts scheduling problem backward, improves electrochemical device's reliability and security greatly.

The connection between the first region 1230 and the second conductive sheet 130 may be formed by welding, riveting, bonding with a conductive material, and the like, where the welding manner includes laser welding, resistance welding, ultrasonic welding, and the like, so as to achieve electrical communication between the first conductive sheet 120 and the second conductive sheet 130, and the first region 1230 shown in fig. 1 is a welded region in the second non-bending portion 123, specifically, the electrical communication manner may be selected according to actual needs, and does not need to be limited by the embodiment of the present application.

In some embodiments, the second conductive sheet 130 comprises: a third non-bent portion 131 connected to the second non-bent portion 123, a second bent portion 132 connected to the third non-bent portion 131, and a fourth non-bent portion 133 connected to the second bent portion 132.

In some embodiments, the first bending portion 122 and the second bending portion 132 are located on the same side of the first region 1230 along the thickness H direction of the pole piece assembly 110.

In some embodiments, the bending angle of the first bending portion 122 is α, and 80 ≦ α ≦ 100. The bending angle α is determined by extending the first non-bending portion 121 and the second non-bending portion 123 to intersect, and an included angle between the first non-bending portion 121 and the second non-bending portion 123 is 180 ° - α. By setting the bending angle a of the first bending portion 122 to be in a range of 80 ° to 100 °, the risk of short circuit caused by interference between the second non-bending portion 123 and the pole piece assembly 110 can be reduced while the head space is further reduced and the volumetric energy density is increased.

In some embodiments, the length of the second non-bent portion 123 is less than the thickness H of the pole piece assembly 110; the length of the second non-bent portion 123 is smaller than the thickness H of the pole piece assembly 110, and the bending angle a of the first bent portion 122 can be set to be close to 90 °, so as to better balance the increase of the volumetric energy density and the risk of short circuit caused by interference between the second non-bent portion 123 and the pole piece assembly 110.

Referring to fig. 2, in some embodiments, an insulating member 150 is disposed on a surface of the first bending portion 122.

In some embodiments, an insulator 150 is disposed between the second non-bent portion 123 and the pole piece assembly 110. By providing the insulating member 150 between the second non-bent portion 123 and the pole piece assembly 110, the risk of short circuit caused by interference between the second non-bent portion 123 and the pole piece assembly 110 can be further reduced.

In some embodiments, the second bend 132 has a bend angle β, and 80 ≦ β ≦ 100 °; the bending angle β is determined by extending the third non-bending portion 131 and the fourth non-bending portion 133 to intersect, and an included angle between the third non-bending portion 131 and the fourth non-bending portion 133 is 180 ° - β. The bending angle beta of the second bending part 132 is set within the range of 80-100 degrees, so that the second conducting strip can be conveniently led out of the packaging shell, the lead-out distance is shortened, and the mass energy density of the electrochemical device is improved.

In some embodiments, the third non-bending portion 131 includes a second region 1310 connected to the first region 1230, and an insulating member 150 is disposed on a surface of the second region 1310; by providing the insulating member 150 on the surface of the second region, damage to the package case by a sharp portion (e.g., a solder mark) at the connection between the first conductive sheet and the second conductive sheet can be reduced, and the service life of the electrochemical device can be prolonged.

In some embodiments, the insulation 150 comprises an insulating tape.

In some embodiments, the surface of the fourth non-bent portion 133 is provided with a tab glue 160.

In some embodiments, the first conductive sheet 120 is integrally formed.

In some embodiments, the second conductive sheet 130 is integrally formed.

In some embodiments, the pole piece assembly 110 includes at least one of a wound structure or a laminated structure.

In some embodiments, the electrode assembly 100 includes a plurality of the first conductive sheets 120, and the plurality of the first conductive sheets 120 are connected by a plurality of the second non-bent portions 123.

In some embodiments, the pole piece assembly 110 includes a positive pole piece, a negative pole piece, and a separator film positioned between the positive and negative pole pieces.

In some embodiments, the positive electrode tab includes a positive electrode current collector and a positive electrode active material layer disposed on the positive electrode current collector. The positive electrode active material layer may be located on one side or both sides of the positive electrode current collector. In some embodiments, the positive electrode current collector may be an aluminum foil, but other positive electrode current collectors commonly used in the art may also be used. In some embodiments, the positive active material may include at least one of lithium cobaltate, lithium manganate, lithium iron phosphate, lithium iron manganese phosphate, lithium nickel cobalt manganate, lithium nickel cobalt aluminate, or lithium nickel manganate, and the positive active material may be doped and/or coated.

In some embodiments, the negative electrode tab may include a negative electrode current collector and a negative active material layer disposed on the negative electrode current collector. The anode active material layer may be disposed on one side or both sides of the anode current collector. In some embodiments, the negative electrode current collector may employ at least one of a copper foil, a nickel foil, or a carbon-based current collector. In some embodiments, the negative active material layer may include a negative active material. In some embodiments, the negative active material includes at least one of a carbon material or a silicon-based material. In some embodiments, the carbon material comprises at least one of graphite, hard carbon, soft carbon; the silicon-based material includes at least one of silicon, a silicon oxy-compound, a silicon carbon compound, or a silicon alloy.

When the electrode assembly 100 shown in fig. 1 is manufactured, first, according to a cell design requirement, a first conductive sheet 120 connected to a positive electrode tab or a negative electrode tab of the electrode tab assembly 110 is bent from a tab area to a non-tab area along a thickness H direction of the electrode tab assembly 110 by an angle a; then, cutting the head of the first conductive sheet 120 (the second non-bent portion 123 in fig. 1 is flush) by using a cutting die to keep the head of the first conductive sheet 120 flush; then, the bottom of the second conductive sheet 130 (the lower end of the third non-bent portion 131 in fig. 1) bent by an angle β is welded or riveted to the head of the first conductive sheet 120, so as to form the first region 1230 and the second region 1310; meanwhile, the insulating member 150 (green glue) is disposed at the bent portion (the first bent portion 122) of the first conductive sheet 120, between the second non-bent portion 123 and the pole piece assembly 110, and at the connection portion (i.e., the surface of the second region 1310), so that the electrode assembly 100 which is not easily bounced and is convenient to be housed is manufactured.

In a second aspect of the embodiments of the present invention, an electrochemical device is provided, please refer to fig. 2, which illustrates a structure of an electrochemical device provided in an embodiment of the present invention, wherein the electrochemical device 200 includes: the electrode assembly 100 as described in the first embodiment above.

The electrochemical device 200 is a device capable of converting chemical energy into electrical energy, and specific examples thereof include all kinds of primary batteries, secondary batteries, fuel cells, solar cells, or capacitors. In particular, the electrochemical device is a lithium secondary battery including a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery, or a lithium ion polymer secondary battery. .

In some embodiments, please refer to fig. 3, which illustrates a structure of an electrochemical device 200 provided in the embodiments of the present application, wherein the electrochemical device 200 further includes:

a package case 210 including a receiving groove (not shown) for receiving the pole piece assembly 110, the first non-bent portion 121, the first bent portion 122, the second non-bent portion 123, the third non-bent portion 131, and the second bent portion 132 of the electrode assembly 100 therein (not shown);

the second conductive sheet 130 further includes an extending portion 134 located outside the package housing 110, and the extending portion 134 is connected to the fourth non-bent portion 133.

In the embodiment of the present application, the electrochemical device 200 employs the electrode assembly 100 as described in the first embodiment, so that the difficulty of mounting the electrode assembly 100 into the receiving slot of the package case 210 can be effectively reduced, the head space of the package case 210 can be released, the energy density of the electrochemical device 200 is improved, the problems of the electrode tab being inserted upside down due to the excessively small head space and the like are avoided, and the reliability and the safety of the electrochemical device 200 can be effectively improved.

In a third aspect of the embodiments of the present application, referring to fig. 4, a structure of an electric device 300 provided in an embodiment of the present application is shown, where the electric device 300 includes the electrochemical device 200 according to the second embodiment.

The electric device of the present application is not particularly limited. In some embodiments, the powered device of the present application includes, but is not limited to, a notebook computer, a pen-input computer, a mobile computer, an electronic book player, a portable phone, a portable facsimile machine, a portable copier, a portable printer, a headphone, a video recorder, a liquid crystal television, a handheld cleaner, a portable CD player, a mini-disc, a transceiver, an electronic notebook, a calculator, a memory card, a portable recorder, a radio, a backup power source, an electric motor, an automobile, a motorcycle, a power-assisted bicycle, a lighting fixture, a toy, a game machine, a clock, an electric tool, a flashlight, a camera, a large household battery, a lithium ion capacitor, and the like.

The embodiment of the application provides an electrode assembly which can be applied to an electrochemical device of electric equipment, the electrode assembly comprises a pole piece assembly, a first conducting strip and a second conducting strip, and the first conducting strip comprises: with the first non-kink that the pole piece subassembly is connected, with the first kink that first non-kink is connected, and, with the second non-kink that first kink is connected, wherein, the second non-kink include with the first region that the second conducting strip is connected, the electrode subassembly that this application embodiment provided does not have the bounce that many times of buckling brought because first conducting strip only has once buckling, consequently first conducting strip is difficult to bounce back, has effectively reduced the degree of difficulty that the shell was gone into to the electrode subassembly packing, has promoted electrochemical device's use reliability and security greatly.

The above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the same; within the context of the present application, where technical features in the above embodiments or in different embodiments can also be combined, the steps can be implemented in any order and there are many other variations of the different aspects of the present application as described above, which are not provided in detail for the sake of brevity; 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 the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An electrode assembly, comprising: the pole piece assembly comprises a pole piece assembly, a first conducting plate and a second conducting plate;

2. The electrode assembly of claim 1,

the second conductive sheet includes: a third non-bending portion connected to the second non-bending portion, a second bending portion connected to the third non-bending portion, and a fourth non-bending portion connected to the second bending portion.

3. The electrode assembly of claim 2,

along the thickness direction of the pole piece assembly, the first bending part and the second bending part are located on the same side of the first area.

4. The electrode assembly of claim 1, wherein the electrode assembly satisfies at least one of the following conditions:

a) the bending angle of the first bending part is alpha, and alpha is more than or equal to 80 degrees and less than or equal to 100 degrees;

b) the length of the second non-bending part is smaller than the thickness of the pole piece assembly;

c) the surface of the first bending part is provided with an insulating part.

5. The electrode assembly of claim 1, wherein an insulator is disposed between the second non-bent portion and the pole piece assembly.

6. The electrode assembly of claim 2, wherein the electrode assembly satisfies at least one of the following conditions:

d) the bending angle of the second bending part is beta, and the beta is more than or equal to 80 degrees and less than or equal to 100 degrees;

e) the third non-bending part comprises a second area connected with the first area, and an insulating part is arranged on the surface of the second area;

f) and the surface of the fourth non-bending part is provided with tab glue.

7. The electrode assembly of claim 2, wherein the electrode assembly satisfies at least one of the following conditions:

i) the first conducting strip is integrally formed;

ii) the second conductive sheet is integrally formed;

iii) the pole piece assembly comprises at least one of a wound structure or a laminated structure;

iv) the electrode assembly includes a plurality of the first conductive sheets connected by a plurality of the second non-bent portions.

8. An electrochemical device, comprising: an electrode assembly as claimed in any one of claims 1 to 7.

9. The electrochemical device of claim 8, further comprising:

a package case including a receiving groove, the electrode assembly, the first non-bending portion, the first bending portion, the second non-bending portion, the third non-bending portion, and the second bending portion being received in the receiving groove;

10. An electrical device, comprising: an electrochemical device as claimed in any one of claims 8 to 9.