CN113258028A - Electrochemical device and electronic device - Google Patents

Electrochemical device and electronic device Download PDF

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Publication number
CN113258028A
CN113258028A CN202110521362.5A CN202110521362A CN113258028A CN 113258028 A CN113258028 A CN 113258028A CN 202110521362 A CN202110521362 A CN 202110521362A CN 113258028 A CN113258028 A CN 113258028A
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China
Prior art keywords
structural member
electrochemical device
pole piece
winding
section
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Granted
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CN202110521362.5A
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Chinese (zh)
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CN113258028B (en
Inventor
张辉华
王慧鑫
汪颖
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Ningde Amperex Technology Ltd
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Ningde Amperex Technology Ltd
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Priority to CN202110521362.5A priority Critical patent/CN113258028B/en
Publication of CN113258028A publication Critical patent/CN113258028A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H01M10/0587—Construction or manufacture of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Abstract

The application discloses an electrochemical device and an electronic device. The electrochemical device comprises a first current collector and a first structural member arranged on the first current collector, wherein the first current collector comprises a first part and a second part which are sequentially connected, the first structural member is arranged on the first part, and the distance between the first structural member and the winding starting end of the first part is not more than half of the length of the first section; and/or the first structural member is arranged on the third part, and the distance between the first structural member and the winding starting end of the first part is not more than half of the length of the third part, so that the supporting force provided by the first structural member is realized, the purpose of inhibiting the side edge of the first section from being folded when the first section is rolled is achieved, and the problem that the first part in the first pole piece is folded is reduced.

Description

Electrochemical device and electronic device
Technical Field
The present application relates to the field of electrochemical technologies, and in particular, to an electrochemical device and an electronic device.
Background
Lithium ion batteries have been widely used in products such as mobile communication terminals, instruments and meters, electric tools, fitness equipment, medical instruments, energy storage devices, power devices, and the like.
The electrode pole piece in the lithium ion battery with the winding structure is arranged in a winding mode. The electrode pole piece comprises a current collector and an active substance layer arranged on the current collector. The electrode pole piece comprises a single-face coating part and a double-face coating part along the winding direction, wherein one face of the single-face coating part is provided with a first active material layer, the other face of the single-face coating part is not provided with the active material layer, and the two faces of the double-face coating part are both provided with the active material layers.
When a wound battery is produced, in the process of winding the electrode pole piece, the single-side coating part is curled towards the middle along two sides of the width direction of the electrode pole piece, namely the single-side coating part is easy to turn over, so that the yield of the wound battery can be reduced, the problem of lithium precipitation can be caused, and the safety performance is reduced.
Disclosure of Invention
In view of this, the present application provides an electrochemical device and an electronic device to solve the problem that the side edge of the area coated with an active material layer on one side is easily folded when the electrode sheet is wound.
A first object of the present application provides an electrochemical device comprising an electrode assembly, wherein the electrode assembly comprises: a first pole piece and a first structural member. The first pole piece comprises a first current collector and a first active material layer arranged on the first current collector, the first pole piece is wound, the first current collector comprises a first surface facing the winding center and a second surface opposite to the first surface, furthermore, the first current collector comprises a first part and a second part which are sequentially connected along the winding direction, the first surface of the second part and the second surface of the second part are both provided with the first active material layer, the second surface of the first part is provided with the first active material layer, and the first surface of the first part is not provided with the active material layer. The first part comprises a first section and a first bending section which are sequentially connected along the winding direction, the first section comprises a winding starting end of the first part, the first structural member is arranged on a first surface of the first section, and the length of the first section is D along the winding direction1. The electrochemical device satisfies at least one of the following conditions:
(1) the first structural member has a distance D from the winding start end of the first portion in the winding direction2，D2≤0.5D1。
(2) First of allThe current collector further comprises a third part, the third part and the first part are sequentially connected along the winding direction, the first active material layer is not arranged on the first surface of the third part and the second surface of the third part, the first structural member is arranged on the first surface of the third part, and the distance from the first structural member to the winding starting end of the first part is D3，D3≤0.5D1。
In the electrochemical device, the first structural member is arranged on the first surface of the first part, and the distance from the winding starting end of the first part is not more than half of the length of the first section; and/or the first structural member is arranged on the first surface of the third part, and the distance from the winding starting end of the first part is not more than half of the length of the third part. The supporting force provided by the first structural part is utilized to achieve the purpose of inhibiting the first section side edge from being turned over when the first section is rolled, so that the risk of the problem of turning over the first part in the first pole piece is reduced.
In one embodiment, the electrode assembly further comprises a second pole piece, wherein the second pole piece is wound with the first pole piece; the first section comprises a first area, and the first area is an area which exceeds the winding starting end of the second pole piece in the first section. The first structural member is arranged on the first surface of the first area, and is beneficial to inhibiting the overturning problem of the first area.
In one embodiment, the winding start end of the first portion is located closer to the winding center than the winding start end of the second pole piece.
In one embodiment, the number of the first structural members is plural.
In one embodiment, the plurality of first structural members are disposed along the winding direction, which facilitates forming a plurality of supporting forces in the winding direction that inhibit the first segment from being folded.
In one embodiment, the projections of the at least two first structural members in the thickness direction of the electrode assembly are arranged in an overlapping manner, which is advantageous for enhancing the effect of suppressing the folding of the first section.
In one embodiment, the first structural member has a length L in the first direction1The length of the first pole piece is L2，0.8L2≤L1≤L2The first direction is perpendicular to the winding direction and the thickness direction of the electrode assembly, which is beneficial to enabling the area of the first structural component extending to the adjacent side edge to reduce the problem of the turnover of the first section of the side edge.
In one embodiment, the first structural member is disposed at an edge of the first segment in a first direction perpendicular to the winding direction and the thickness direction of the electrode assembly, which is advantageous for enhancing a supporting force of the edge of the first segment in the first direction.
In one embodiment, the first structural member includes a plurality of first structural members and is disposed at intervals in the winding direction.
In one embodiment, the plurality of first structural members are disposed at two edges of the first surface of the first segment and are symmetrical with respect to a middle line of the first pole piece in the length direction, which is beneficial to providing a symmetrical supporting force for the first segment.
In one embodiment, the elastic modulus E of the first structural member is greater than or equal to 0.5Pa, which is beneficial to providing enough supporting force for the first section.
In one embodiment, the first structural member comprises at least one of a metal structural member, a ceramic structural member, or a polymer structural member.
In one embodiment, the polymeric structural member comprises a gummed paper.
In one embodiment, the first structural member is a metal structural member and is connected with the first current collector, one end of the first structural member extends beyond the first current collector in a first direction, and the first direction is perpendicular to the winding direction and the thickness direction of the electrode assembly, so that the first structural member can be used as a tab.
In one embodiment, the first structural member is connected with the first current collector through a welding seal, which is beneficial to reducing internal resistance between the first structural member and the current collector.
A second object of the present application is to provide an electronic device, including the above electrochemical device.
In the electronic device, the first structural member is arranged on the first surface of the first part, and the distance from the winding starting end of the first part is not more than half of the length of the first section; and/or the first structural member is arranged on the first surface of the third part, and the distance from the winding starting end of the first part is not more than half of the length of the third part. The supporting force provided by the first structural part is utilized to achieve the purpose of inhibiting the first section side edge from being turned over when the first section is rolled, so that the problem that the first part in the first pole piece is turned over is reduced.
Drawings
In order to more clearly illustrate the technical solutions in 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 other drawings can be obtained by those skilled in the art according to the drawings.
Fig. 1 is a schematic view illustrating the structure of an electrode assembly of an electrochemical device according to an embodiment of the present application;
FIG. 2 is a schematic view of the structure of the portion shown in FIG. 1 of the present application;
FIG. 3 is a schematic view of a first pole piece of an electrochemical device according to an embodiment of the present application in an expanded plan view;
FIG. 4 is a schematic illustration of the present application showing the expanded thickness of the first pole piece of FIG. 3;
FIG. 5 is a schematic view illustrating the structure of an electrode assembly of an electrochemical device according to an embodiment of the present application;
FIG. 6 is a schematic view illustrating the structure of an electrode assembly of an electrochemical device according to an embodiment of the present application;
FIG. 7 is an expanded plan view of a first structural member disposed on a third portion of a first pole piece according to one embodiment of the present disclosure;
FIG. 8 is a schematic view of the first pole piece of FIG. 7 according to the present application showing the corresponding expanded thickness;
FIG. 9 is a schematic view of a first pole piece of a plurality of first structural members of an electrochemical device according to an embodiment of the present disclosure;
FIG. 10 is a schematic drawing showing a developed plan view of a first pole piece with a first structural member disposed across the first pole piece in an electrochemical device according to an embodiment of the present disclosure;
FIG. 11 is a schematic diagram illustrating a relationship between lengths of a first structural member and a first pole piece of an electrochemical device according to an embodiment of the present disclosure;
FIG. 12 is a schematic drawing showing a developed plan view of a first pole piece having a first structural member disposed along an edge thereof in an electrochemical device according to an embodiment of the present disclosure;
FIG. 13 is a schematic view of a first electrode sheet with a first structural member disposed in edge symmetry in an electrochemical device according to an embodiment of the present disclosure;
FIG. 14 is a schematic view of a first pole piece of a first structural member of an electrochemical device according to an embodiment of the present application in an expanded plan view;
fig. 15 is a schematic expanded plan view of a first structural member of an electrochemical device according to an embodiment of the present application as a first pole piece of a tab.
Fig. 16 is a schematic expanded plan view of a first structural member of an electrochemical device according to an embodiment of the present application as a first pole piece of a tab.
Fig. 17 is a schematic view of a second side of a first pole piece with a first structural member as a tab of an electrochemical device according to an embodiment of the present disclosure.
Fig. 18 is a schematic view of a second face of a first structural member of an electrochemical device according to an embodiment of the present application as a first pole piece of a tab.
Detailed Description
The technical solutions in the embodiments of the present application are clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are some, but not all embodiments of the present application. The following embodiments and their technical features may be combined with each other without conflict.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise. In the description of the present application, "a number" means at least one, such as one, two, etc., unless specifically limited otherwise.
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 herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. The terms "connected," "electrically connected," and "electrically connected," as used herein, include any direct and indirect electrical or structural connection.
As used herein, symmetry, parallelism, perpendicularity, etc., are allowed within a certain range with reasonable plus or minus deviations, such as plus or minus 10 deg. deviations, given the same concept of the solution.
For convenience of description, referring to fig. 1 to 4, the winding direction, the thickness direction, the first direction, the winding center 103 and the length direction L of the first pole piece mentioned in the present application are defined as follows: for the first pole piece 101 disposed in a winding manner, the winding direction is the direction in which the first pole piece 101 extends in the electrode assembly 10 in a winding manner, and it can be understood that in the straight section, the length direction L of the first pole piece 101 is the same as or opposite to the winding direction; the winding center 103 is a central position around which the first pole piece 101 extends in a winding manner; the first surface 104 is a surface of the current collector facing the winding center 103, and the second surface 105 is another surface opposite to the first surface 104; the thickness direction T refers to the direction in which the first face 104 points toward the second face 105 in the electrode tab. The first direction is perpendicular to the winding direction and the thickness direction T of the electrode assembly 10, and may also be referred to as a width direction W of the first pole piece 101.
Example 1
Referring to fig. 1 to 4, the present embodiment provides an electrochemical device, which is a device for converting chemical energy into electrical energy. Referring to fig. 1 and 4, an electrochemical device includes an electrode assembly 10. The electrode assembly 10 includes a first electrode sheet 101, and the first electrode sheet 101 includes a first current collector 110 and a first active material layer 120 disposed on the first current collector 110. The first pole piece 101 is wound, and the first current collector 110 includes a first surface 104 facing the winding center 103 and a second surface 105 opposite to the first surface 104. In the winding direction, the first current collector 110 includes a first portion 111 and a second portion 112 connected in sequence, the first surface 104 of the second portion 112 and the second surface 105 of the second portion 112 are each provided with the first active material layer 120, the second surface 105 of the first portion 111 is provided with the first active material layer 120, and the first surface 104 of the first portion 111 is not provided with the first active material layer 120.
Referring to fig. 1 to 4, the electrochemical device of the present embodiment further includes a first structural component 130, wherein the first structural component 130 is disposed on the first portion 111. The first portion 111 includes a first section 1111 and a first bent section 1112 sequentially connected along the winding direction, and the first bent section 1112 may be a first bent section of the first portion 111 along the winding direction. The first segment 1111 includes a winding start end 11110 of the first portion 111, the first structural member 130 is disposed on the first surface 104 of the first segment 1111, and the length of the first segment 1111 is D along the winding direction1The distance D from the first structural member 130 to the winding start 11110 of the first portion 1112，D2≤0.5D1. The winding start end 11110 of the first portion 111 refers to an end of the first portion 111 where the winding starts in the winding direction. Distance D2Refers to a distance from a point of the first structural member 130 closest to the winding start end 11110 of the first portion 111, in other words, a minimum distance from the first structural member 130 to the winding start end 11110 of the first portion 111. In one embodiment, distance D2May be a distance from an edge of the first structural member 130 closest to the winding start end 11110 of the first portion 111 in the winding direction to the winding start end 11110 of the first portion 111.
In the electrochemical device of this embodiment 1, by providing the first structural member 130, because the first structural member 130 has a certain mechanical strength, the first structural member 130 is disposed on the first surface 104 of the first section 1111, for example, the first structural member 130 is disposed at a position away from the winding start end 11110 of the first portion 111 by no more than half of the length of the first section 1111, so that the supporting force provided by the first structural member 130 can achieve the purpose of suppressing the side folding of the first section 1111 when the first section 1111 is rolled, thereby improving the problem of the first section 1111 in the first pole piece 101.
In the first electrode sheet 101, the first active material layer 120 is a layer containing a first active material capable of inserting and extracting lithium ions. In some embodiments, the first active material may be a positive electrode active material. In some embodiments, the first active material may be a negative active material. In some embodiments, the positive electrode active material includes at least one of lithium cobaltate, lithium iron phosphate, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminate, or lithium manganese oxide. In some embodiments, the negative active material may include at least one of a carbon material or a silicon material. While the absence of the first active material layer 120 on the first current collector 110 does not mean that other material layers are not provided, it is possible to provide some conductive layers, insulating layers, and the like.
In the present embodiment, the electrochemical device includes an electrode assembly 10, an electrolyte (not shown), and a case having a receiving space, and the electrode assembly 10 and the electrolyte are disposed in the receiving space of the case. The electrode assembly 10 is a core component of an electrochemical device and performs a reversible electrochemical reaction in cooperation with an electrolyte, thereby performing a charge and discharge process of the electrochemical device.
The electrode assembly 10 may perform a redox reaction with an electrolyte solution to exchange ions with the electrolyte solution. In use, the electrode assembly 10 is electrically connected to terminals of an external electronic component by means of respective conductors (e.g., tabs) to form a current path.
Specifically, the electrode assembly 10 includes a first pole piece 101. The first pole piece 101 includes a first current collector 110 and a first active material layer 120. The first active material layer 120 includes a material capable of ion exchange with the electrolytic solution by a redox reaction.
In the first pole piece 101, the first active material layer 120 is provided on the first current collector. Specifically, the first pole piece 101 includes a first current collector 110, and a first active material layer 120 disposed on the first current collector 110.
Further, the first pole piece 101 has a first portion 111 and a second portion 112. Specifically, in the first pole piece 101, the first portion 111 and the second portion 112 are connected in order in the winding direction. The second face 105 of the first portion 111 is provided with the first active material layer 120, and the first face 104 of the first portion 111 is not provided with an active material layer, and since only one face is provided with the first active layer, the first portion 111 may also be referred to as a single face region. The first side 104 of the second portion 112 and the second side 105 of the second portion 112 are both provided with the first active material layer 120, and the second portion 112 may also be referred to as a double-sided region because both sides are provided with the first active layer.
Example 2
Referring to fig. 5 to 8, the electrochemical device includes an electrode assembly 10, wherein the electrode assembly 10 includes a first pole piece 101, the first pole piece 101 includes a first current collector 110 and a first active material layer 120 disposed on the first current collector 110, the first pole piece 101 is wound, and the first current collector 110 includes a first surface 104 facing a winding center 103 and a second surface 105 opposite to the first surface 104. In the winding direction, the first current collector 110 includes a first portion 111 and a second portion 112 connected in sequence, the first surface 104 of the second portion 112 and the second surface 105 of the second portion 112 are each provided with a first active material layer 120, the second surface 105 of the first portion 111 is provided with the first active material layer 120, and the first surface 104 of the first portion 111 is not provided with an active material layer.
The first collector 110 further includes a third portion 113, the third portion 113 and the first portion 111 are sequentially connected in a winding direction, the first active material layer 120 is not disposed on both the first surface 104 and the second surface 105 of the third portion 113, the first structural member 130 is disposed on the first surface 104 of the third portion 113, and a distance D from the first structural member 130 to a winding start end 11110 of the first portion 1113，D3≤0.5D1。
In some implementations, the first support 130 is disposed on the first side 104 of the third portion 113, which is beneficial for improving the folding problem of the first section 111. Optionally, the distance D of the winding start end 11110 of the first portion 1113Less than or equal to the length D of the first segment 11111Half of the time, the folding over problem of the first section 1111 can be improved.
In the winding direction, the secondA segment 1111 extends from the winding start end 11110 of the first portion 111 to connect with the first bending segment 1112. It can be seen that the first section 1111 extends in the winding direction from a straight section to a connection with the first angled section 1112, D1Is the length of the straight section, as shown in fig. 6.
In some implementations, the first structural member 130 is disposed on the first side 104 of the third portion 113, and the third portion 113 has a length D along the winding direction4The distance D from the first structural member 130 to the winding start 11110 of the first portion 1113，D3≤0.5D4。
Note that, in the present embodiment, the distance D from the first structural member 130 to the winding start end 11110 of the first portion 111 is3Refers to a distance from a point of the first structural member 130 closest to the winding start end 11110 of the first portion 111, in other words, a minimum distance from the first structural member 130 to the winding start end 11110 of the first portion 111.
In the electrode assembly 10, the third portion 113 is connected to the first portion 111 and extends from the connection with the first portion 111 toward the winding center 103 (opposite to the winding direction), specifically, extends in a straight section as shown in fig. 5, or extends to the winding center 103 after being bent as shown in fig. 6.
In this embodiment, when the first structural member 130 is disposed on the third portion 113 and is spaced from the winding start end 11110 by less than a certain distance, specifically, is spaced from the winding start end 11110 of the first portion 111 by no more than half of the length of the third portion 113, which is beneficial to improving the folding problem of the first section 1111. In the present embodiment, the first structural member 130 is disposed on the first surface 104 of the third portion 113, and is not more than half of the length of the third portion 113 from the winding start end 11110 of the first portion 111, so that the supporting force provided by the first structural member 130 is beneficial to prevent the first section 1111 from being folded when the first section 1111 is rolled or wound.
In some of these implementations, a first structural member 130 is disposed on the first side 104 of the first segment 1111, while a first structural member 130 is disposed on the first side 104 of the third portion 113,and D2≤0.5D1，D3≤0.5D1. It will be appreciated that the first support member 130 is disposed on both the first section 1111 and the first side 104 of the third portion 113, which is beneficial to improve the effect of inhibiting the side folding of the first section 1111.
Example 3
At least one of the following embodiments is further adopted on the basis of example 1 and/or example 2.
The first structural member 130 is a member having a supporting function. Based on this, the first structural member 130 itself needs to have certain mechanical properties to enhance the effect of suppressing the first section 1111 in the first portion 111 from being folded. In one embodiment, the elastic modulus E of the first structural member 130 is 0.5Pa or higher.
In one embodiment, the first structure 130 is a sheet structure and is attached to the surface of the first current collector 110. Optionally, the first structural component 130 is one of a ceramic structural component, a metal structural component, or a polymer structural component. For example, the polymeric structure includes gummed paper. In addition, the first structural member 130 may also be a metal sheet, a ceramic sheet, a silicon sheet, or a polymer sheet.
In one embodiment, the number of the first structural members 130 is plural. By providing an appropriate number (e.g., 2 or 3) of the first structural members 130, the effect of suppressing the first section 1111 of the first pole piece 101 from being folded can be improved.
Alternatively, referring to fig. 9, the plurality of first structural members 130 are disposed along the winding direction. That is, the plurality of first structural members 130 are distributed on the first surface 104 of the first portion 111 and/or the second portion 112 in the winding direction. For example, the plurality of first structural members 130 are strip-shaped structural members, wherein the plurality of first structural members 130 are disposed parallel to the first direction W of the first pole piece 101, and the plurality of structural members are disposed parallel to each other and parallel to the first direction W, so that the coverage area in the first direction W is larger, and the side edge in the first direction W closer to the first end is more beneficial to improving the effect of suppressing the side edge of the first section 1111 from being folded.
Alternatively, referring to fig. 10, the projections of at least two first structural members 130 in the thickness direction T of the electrode assembly 10 are overlapped, in other words, the projections of a plurality of first structural members 130 in the thickness direction T of the electrode assembly 10 are arranged to intersect with each other, which can cooperatively improve the supporting effect on the first section 1111 of the first pole piece 101. Generally, in the arrangement where a plurality of first structural members 130 are arranged to intersect with each other, the intersection can provide a large supporting force, and the intersection can be arranged at a position where the first section 1111 is easy to fold.
In one embodiment, referring to fig. 11, the first structural member 130 has a length L in the first direction W1The length of the first pole piece 101 is L2，0.8L2≤L1≤L2Wherein the first direction W is perpendicular to the winding direction and the thickness direction T of the electrode assembly 10.
The first structural member 130 has a length L1The length of the first pole piece 101 is L2，0.8L2≤L1≤L2That is, the maximum distance between the first structural member 130 and the side of the first pole piece 101 in the first direction W is 0.2L2. It can be seen that the length of the first structural member 130 is greater than or equal to 0.8 times the length of the first pole piece 101, and the maximum distance between the first structural member 130 and the side of the first pole piece 101 in the first direction W is controlled to be 0.2L2The effect of restraining the side edge of the first section 1111 from being folded is effectively improved.
In one embodiment, referring to fig. 12, the first structural member 130 is disposed at an edge of the first section 1111 in a first direction W perpendicular to the winding direction and the thickness direction T of the electrode assembly 10. Here, the edge of the first section 1111 in the first direction W refers to an area of the first section 1111 near the side edge in the first direction W, and it can be seen that the edge of the first section 1111 extends in the winding direction. By providing the first structural member 130 at the edge of the first section 1111 in the first direction W, the problem of the side folding of the first section 1111 in the first direction W is specifically suppressed.
In one embodiment, referring to fig. 13, the first structural member 130 includes a plurality of members and is disposed at intervals along the winding direction. The effect of suppressing the first structural member 130 from being folded back in the winding direction can be enhanced by providing a plurality of first structural members 130. The first structural member 130 may be disposed in close contact with the winding direction.
In one embodiment, referring to fig. 13, the first structural members 130 are disposed at two edges of the first surface 104 of the first segment 1111 and are symmetrical with respect to a center line 106 of the first pole piece 101 in the length direction L. By symmetrically arranging the plurality of first structural members 130 on two edges of the first surface 104 of the first section 1111, the problem that the first section 1111 is folded due to unbalanced supporting force provided by the asymmetrical arrangement of the first structural members 130 can be reduced.
Referring to fig. 14, the first pole piece 101 is provided with two first structural members 130 located at the edge of the first section 1111 in the first direction W and the first structural member 130 arranged along the first direction W, and structural members are arranged at the intersection of the two first structural members 130 located at the edge of the first section 1111 in the first direction W and the first structural member 130 arranged along the first direction W in the thickness direction T, so as to specifically enhance the supporting force of the first section 1111 in the side edge of the first direction W and suppress the first section 1111 from being folded in the winding direction and the first direction W.
In one embodiment, the first structural member 130 is used as a tab by utilizing the conductivity of the first structural member 130. Specifically, the first structure 130 includes a metal material and is connected to the first current collector 110, and one end of the first structure 130 protrudes beyond the first current collector 110 in a first direction W perpendicular to the winding direction and the thickness direction T of the electrode assembly 10.
One end of the first structure member 130 is protruded to the outside of the first current collector 110 based on the conductivity of metal to form a tab. That is, the first structural member can suppress the effect of the first section 1111 being folded over, and can be used as a tab by using a metal material thereof. Optionally, the electrode assembly 10 further includes a tab glue 131 disposed on the first structural member 130 to extend out of the first current collector portion for hot melt bonding with the case.
By way of example, an electrode assembly 10 suitable for use in a non-multi-tab configuration (non-MTW configuration) is provided. The first structure 130 is disposed on the first face 104 of the first section 1111 in the electrode assembly 10 of the non-multi tab structure, and the first face 104 of the first section 1111 is not disposed with the first active material layer 120, so the first face 104 of the first section 1111 is actually the first current collector 110, i.e., the first structure 130 is disposed on the first current collector 110. It should be noted that, in the electrode assembly 10 with the multi-tab structure, each electrode tab is provided with a plurality of tabs, for example, each winding layer is provided with one tab, but not each electrode tab in the electrode assembly 10 with the multi-tab structure is provided with one tab.
In one embodiment, the first structure 130 is connected to the first current collector 110 by a solder mark 132. That is, the first structure member 130 is welded to the first current collector 110. The welding of the first structural member 130 and the first current collector 110 is a connection manner of the first structural member 130 and the first current collector 110, and the first structural member 130 and the first current collector 110 can be electrically connected, so that the first structural member 130 functions as a tab.
Alternatively, referring to fig. 15 and fig. 16, the welding position may be on the first side 104 of the first segment 1111, and a corresponding position on the second side 105 of the first segment 1111 also needs to reserve a blank foil area for welding the first structural member 130, wherein the blank foil area is an area on the second side 105 of the first segment 1111 where no active material layer is disposed. In addition, referring to fig. 12 and 13, the bonding position is set on the first region 11111 of the first section 1111 of the first portion 111 or on the third portion 113.
Alternatively, referring to fig. 17 and 18, the number of the solder marks 132 may be multiple, and the multiple solder marks 132 are uniformly distributed along the first direction W, so as to avoid an imbalance of internal stress caused by an asymmetric distribution of the solder marks 132. Further, the solder marks 132 are symmetrically distributed in the first direction W, that is, the plurality of solder marks 132 are patterned into a symmetrical pattern, and the symmetry axis may be the middle line 106 of the length direction L of the first pole piece 101. For example, the first structural member 130 is welded on the first side 104 of the first section 1111, and the number of the welding imprints 132 is greater than or equal to 2, wherein a plurality of welding imprints 132 are uniformly and symmetrically distributed on the pole piece in the first direction W to form uniform supporting strength.
In addition, because the welding seal 132 is more numerous, more be favorable to preventing that the district's pole piece of single face is crooked and turn over a book, be favorable to preventing to coil the pan feeding and turn over a problem of rolling over, moreover, more welding seal 132 can also reach the effect that reduces electric core impedance.
In one embodiment, the electrode assembly 10 further includes a second pole piece, which is wound around the first pole piece 101; the first section 1111 includes a first region 11111, and the first region 11111 is a region of the first section 1111 beyond the winding start end 11110 of the second pole piece; the first structure 130 is disposed on the first surface 104 of the first region 11111.
It should be noted that the second pole piece includes the second current collector 140, and the second active material layer 150 disposed on the second current collector 140. Here, the first active material layer 120 and the second active material layer 150 may have different compositions. For example, the second active material layer 150 may specifically include graphite or the like.
Referring to fig. 1 and fig. 2, the first region 11111 is a portion of the first segment 1111, and the first region 11111 is a region of the first segment 1111 beyond the winding start 11110 of the second pole piece. In other words, in the thickness direction T, the second pole piece is projected into the first segment 1111, the first region 11111 is the region of the first segment 1111 not covered by the projection of the second pole piece 102, and the projection of the second pole piece 102 is the perpendicular projection of the second pole piece 102 on the first segment 1111.
Generally, the area of the first section 1111 of the first portion 111 is larger than the area of the corresponding portion of the second plate 102, so as to reduce the problem of lithium deposition. When the first pole piece 101 and the second pole piece are wound, the area of the first section 1111 beyond the second pole piece 102 is the first area 11111. The edge region of the first section 1111 of the first pole piece 101 protrudes towards the outside of the second pole piece.
It can be seen that the first region 11111 is generally adjacent to the side edge of the first section 1111 and is a region where folding is more likely to occur, and that the folding problem of the first section 1111 can be advantageously reduced by disposing at least a portion of the first structural member 130 on the first side 104 of the first region 11111.
In one embodiment, the winding start 11110 of the first portion 111 is closer to the winding center 103 than the winding start 11110 of the second pole piece. That is, the first region 11111 includes a region adjacent to the winding start end 11110 of the first portion 111, and the provision of at least part of the first structural member 130 in the first region 11111 is advantageous in suppressing the problem of the winding start end 11110 of the first portion 111 being folded. In addition, by disposing the first structural member 130 in the first region 11111, the problem of poor interface contact due to uneven thickness of the first section 1111 can be improved.
In summary, by providing the first structural member 130 on the first pole piece 101, the first section 1111 can be prevented from being folded in the first direction W by the supporting function of the first structural member 130 itself, thereby preventing the problem of folding of the feeding material during winding.
Example 4
As shown in fig. 3 and 4, in the first pole piece 101 of the embodiment, specifically, the distance from the first structural member 130 to the winding start end 11110 of the first portion 111 is 0.1D1. The first structural member 130 is made of green glue and is in a strip shape, and is adhered to the first surface 104 of the first section 1111. The length of the green glue in the first direction W is 0.8 times the length of the first pole piece 101 in the first direction W, and the longer side of the green glue is parallel to the first direction W.
Example 5
Fig. 16 and 17 show the first structural member 130 of this embodiment. Specifically, the distance from the first structural member 130 to the winding start end 11110 of the first portion 111 is 0.1D1The first structural member 130 is a strip-shaped copper sheet, and the first structural member 130 is welded to the first current collector 110, one end of the first structural member 130 extends out of the first current collector 110 to form a tab, and the other end of the first structural member is overlapped with a side edge of the first current collector 110, wherein the number of the welding prints 132 is 4, and the welding prints are uniformly distributed in the first direction W and are symmetrical about the central line 106 in the length direction L.
Example 6
This embodiment provides an electronic device, comprising the electrochemical device as described in any of the above embodiments. The electrochemical device can be used as an energy supply device of an electronic device, and specifically, the electrochemical device can perform electrochemical reaction to provide electric energy for the electronic device. The electronic device can be understood as an electric appliance, and specifically can be a mobile communication terminal, an instrument, an electric tool, a fitness equipment, a medical instrument, an energy storage device, a power device and other equipment products.
The first structural member 130 is arranged on the first pole piece 101 in the electrochemical device, so that the turnover of the first section 1111 in the first pole piece 101 can be effectively inhibited, the yield of the electrochemical device is improved, and the production cost of electronic equipment is reduced.
Although the application has been shown and described with respect to one or more implementations, equivalent alterations and modifications will occur to others skilled in the art based upon a reading and understanding of this specification and the annexed drawings. This application is intended to embrace all such modifications and variations and is limited only by the scope of the appended claims. In particular regard to the various functions performed by the above described components, the terms used to describe such components are intended to correspond, unless otherwise indicated, to any component which performs the specified function of the component (e.g., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary implementations of the specification.
In addition, in the description of the present application, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, should not be considered as limiting the present application.

Claims (14)

1. An electrochemical device comprising an electrode assembly, wherein the electrode assembly comprises:
a first pole piece including a first current collector and a first active material layer disposed on the first current collector, the first pole piece being wound, the first current collector including a first face facing a winding center and a second face opposite to the first face,
in a winding direction, the first current collector includes a first portion and a second portion connected in sequence, the first surface of the second portion and the second surface of the second portion are both provided with the first active material layer, the second surface of the first portion is provided with the first active material layer, and the first surface of the first portion is not provided with the active material layer; and
a first structural member;
the first part includes along first section and the first bending segment that the direction of coiling connected gradually, first section includes the coiling initiating terminal of first part, first structural component set up in first section first face, along the direction of coiling, the length of first section is D1，
The electrochemical device satisfies at least one of the following conditions:
the first structural member has a distance D from the winding start end of the first portion in the winding direction2，D2≤0.5D1；
The first current collector further includes a third portion sequentially connected to the first portion in the winding direction, the first active material layer is not provided on the first surface of the third portion and the second surface of the third portion, the first structural member is provided on the first surface of the third portion, and a distance from the first structural member to a winding start end of the first portion is D3，D3≤0.5D1。
2. The electrochemical device of claim 1, wherein the electrode assembly further comprises a second pole piece disposed in a wound relationship with the first pole piece;
the first section comprises a first area, and the first area is an area which exceeds the winding starting end of the second pole piece in the first section; the first structural member is disposed on the first surface of the first region.
3. The electrochemical device according to claim 2, wherein a winding start end of the first portion is located closer to the winding center than a winding start end of the second pole piece.
4. The electrochemical device according to claim 1, wherein the first structural member is plural in number,
a plurality of the first structural members are arranged in the winding direction; or
At least two projections of the first structural members in the thickness direction of the electrode assembly are arranged to overlap.
5. The electrochemical device of claim 1, wherein the first structural member has a length L in a first direction1The length of the first pole piece is L2，0.8L2≤L1≤L2The first direction is perpendicular to the winding direction and a thickness direction of the electrode assembly.
6. The electrochemical device according to claim 1, wherein the first structural member is provided to an edge of the first segment in a first direction perpendicular to the winding direction and a thickness direction of the electrode assembly.
7. The electrochemical device according to claim 6, wherein the first structural member includes a plurality of members and is disposed at intervals in the winding direction.
8. The electrochemical device according to claim 7, wherein the plurality of first structural members are disposed at both edges of the first face of the first segment and are symmetrical with respect to a middle line of a length direction of the first pole piece.
9. The electrochemical device according to claim 1, wherein the elastic modulus E of the first structural member is 0.5Pa or more.
10. The electrochemical device of claim 1, wherein the first structural member comprises at least one of a metallic structural member, a ceramic structural member, or a polymer structural member.
11. The electrochemical device of claim 10, wherein the polymeric structure comprises a gummed paper.
12. The electrochemical device according to claim 10, wherein the first structural member is a metal structural member and is connected to the first current collector, one end of the first structural member protrudes beyond the first current collector in a first direction perpendicular to the winding direction and a thickness direction of the electrode assembly.
13. The electrochemical device according to claim 10, wherein the first structural member and the first current collector are connected by a solder print.
14. An electronic device comprising the electrochemical device according to any one of claims 1 to 13.
CN202110521362.5A 2021-05-12 2021-05-12 Electrochemical device and electronic device Active CN113258028B (en)

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