CN117239058B - Pole piece, battery cell and battery - Google Patents

Pole piece, battery cell and battery Download PDF

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Publication number
CN117239058B
CN117239058B CN202311498849.1A CN202311498849A CN117239058B CN 117239058 B CN117239058 B CN 117239058B CN 202311498849 A CN202311498849 A CN 202311498849A CN 117239058 B CN117239058 B CN 117239058B
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China
Prior art keywords
pole piece
layer
current collector
conductive
conductive sheet
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Active
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CN202311498849.1A
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Chinese (zh)
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CN117239058A (en
Inventor
黄琳涵
王涛
盛东辉
谢继春
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Zhuhai Cosmx Battery Co Ltd
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Zhuhai Cosmx Battery Co Ltd
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Priority to CN202410351435.4A priority Critical patent/CN118016808A/en
Priority to CN202311498849.1A priority patent/CN117239058B/en
Publication of CN117239058A publication Critical patent/CN117239058A/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
    • 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
    • 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
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/531—Electrode connections inside a battery casing
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/531—Electrode connections inside a battery casing
    • H01M50/536—Electrode connections inside a battery casing characterised by the method of fixing the leads to the electrodes, e.g. by welding
    • 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

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Connection Of Batteries Or Terminals (AREA)

Abstract

The application provides a pole piece, an electric core and a battery. Wherein, the pole piece includes: a current collector having first and second surfaces opposite to each other in a thickness direction, the first surface including a first coating region and a first blank region adjacent to the first coating region; a first active material layer coated in the first coating region; the conductive structure comprises a first conductive sheet, wherein the first conductive sheet comprises a first main body part and a first connecting part connected with the first main body part, and the first connecting part is fixedly connected in the first blank area; the first filling layer is arranged on one side of the first conducting plate, which is away from the current collector, and the first filling layer covers at least part of the first connecting part. By the technical scheme, the problem that the connection strength between the current collector and the tab in the related technology is poor can be effectively solved.

Description

Pole piece, battery cell and battery
Technical Field
The application relates to the field of battery production, in particular to a pole piece, an electric core and a battery.
Background
Lithium ion batteries have many advantages, and become a major source of power for consumer electronics and electric vehicles. The safety performance and weight reduction of lithium ion batteries have been the object of consumer attention in recent years, particularly in batteries for use in electric vehicles.
In the related art, in order to improve the puncture resistance and the impact resistance of the battery cell, the current collector with the metal foil structure may be replaced by a composite current collector, where the composite current collector includes an insulating layer and metal layers correspondingly disposed on the upper and lower sides of the insulating layer. When the composite current collector and the tab are welded, poor welding effects such as perforation of welding spots, overhigh protrusion of welding spots and the like often occur in actual operation due to the existence of the insulating layer, and further development and application of the composite current collector are seriously affected. On one hand, the welding point perforation can reduce the welding connection strength and the conductivity, and the normal operation of the battery is affected; on the other hand, too high a welding spot bulge can increase the risk of the separator being pierced, so that the safety performance of the battery is threatened; moreover, the junction of the composite current collector and the tab forms a weak area easily, and the composite current collector is broken or torn, so that the electric connection strength of the conductive assembly and the current collector is poor, the overall strength of the pole piece is reduced, and the normal operation of the battery is affected.
Disclosure of Invention
The application provides a pole piece, an electric core and a battery for solve the relatively poor problem of joint strength between the electric current collector and the tab among the related art.
In one aspect, the present application provides a pole piece comprising: a current collector having first and second surfaces opposite to each other in a thickness direction, the first surface including a first coating region and a first blank region adjacent to the first coating region; a first active material layer coated in the first coating region; the conductive structure comprises a first conductive sheet, wherein the first conductive sheet comprises a first main body part and a first connecting part connected with the first main body part, and the first connecting part is fixedly connected in the first blank area; the first filling layer is arranged on one side of the first conducting plate, which is away from the current collector, and the first filling layer covers at least part of the first connecting part.
In some embodiments, the first filler layer is a conductive glue layer.
In some embodiments, the boundary of the first filler layer at least partially coincides with the boundary of the first connection.
In some embodiments, the first connection portion is connected to the current collector by welding, the first connection portion has a first solder mark thereon, and the first filler layer covers the first solder mark.
In some embodiments, the first solder comprises a bump and the first filler layer covers the bump.
In some embodiments, the first solder print further comprises a recess comprising a solder through hole penetrating the current collector and the conductive structure in the thickness direction of the pole piece and/or a solder recess, the first filler layer protruding into the recess.
In some embodiments, the pole piece further comprises: and the first insulating structure is arranged in the first empty region of the current collector and separates the first active substance layer and the first conductive sheet, wherein the first insulating structure comprises a ceramic insulating strip adhered to the first empty region.
In some embodiments, the first insulating structure has a thickness between 1 μm and 100 μm;
and/or the thickness of the first conductive sheet is between 1 μm and 20 μm.
In some embodiments, the thickness of the first filler layer is between 2 μm and 200 μm.
In some embodiments, the difference between the thickness of the first fill layer and the thickness of the first insulating structure is between 0 μm and 5 μm.
In some embodiments, a distance between the first insulating structure and the first filler layer is greater than or equal to 0mm.
In some embodiments, the first connection is disposed at an edge of the first conductive sheet proximate to the first insulating structure.
In some embodiments, the current collector includes a first conductive layer, an insulating layer, and a second conductive layer sequentially disposed in a thickness direction, a surface of the first conductive layer facing away from the insulating layer forming a first surface, and a surface of the second conductive layer facing away from the insulating layer forming a second surface; the second surface comprises a second coating area and a second blank area connected with the second coating area; the conductive structure further comprises a second conductive sheet, the second conductive sheet comprises a second main body part and a second connecting part connected with the second main body part, and the second connecting part is fixedly connected in a second blank area of the current collector; the pole piece further comprises: the second filling layer is arranged on one side of the second conductive sheet, which is away from the current collector, and covers at least part of the connecting part of the second conductive sheet; a second active material layer coated in the second coating region; and the second insulating structure is arranged in the second blank area of the current collector and separates the second active material layer and the second conductive sheet.
In another aspect, the present application provides a battery cell, the battery cell comprising: the first pole piece, the second pole piece and the diaphragm arranged between the first pole piece and the second pole piece are wound or laminated to form; the first pole piece is the pole piece, and the conductive structure of the first pole piece forms a lug structure of the battery cell.
In another aspect, the present application provides a battery comprising: and the battery cell is the battery cell.
The pole piece that this application provided includes the electric current body and fixed connection is at the first conducting strip on the electric current body, and first conducting strip includes first main part and the first connecting portion that links to each other with first main part, and first conducting strip passes through first connecting portion and electric current body fixed connection. According to the scheme, the first conductive sheet is arranged on the current collector and is connected with the electrode lug, so that the electric connection between the current collector and the electrode lug is not limited by the insulating layer, and the conductivity of the electrode plate is effectively improved; furthermore, a first filling layer is arranged on one side of the first conducting strip, which is far away from the current collector, and at least part of the first connecting part is covered by the first filling layer, namely, the connecting part between the first conducting strip and the current collector is reinforced by the first filling layer, and meanwhile, the first conducting strip and the current collector are bonded together by the first filling layer, so that the connecting strength between the first conducting strip and the current collector is effectively ensured, the overall stability of the pole piece is improved, and the current collector of the first connecting part is prevented from being broken or torn; in addition, the first filling layer can prevent the protrusion formed by the first connecting part from penetrating through the diaphragm and contacting with the other pole piece, thereby causing short circuit; and the first filling layer can also fill the perforation possibly existing in the first connecting part, so that the structural strength of the pole piece is ensured.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the application and together with the description, serve to explain the principles of the application.
Fig. 1 is a schematic view of a part of a structure of a pole piece provided in an embodiment of the present application, wherein fig. 1 shows the structure after a first active material layer and a second active material layer are coated on a current collector;
FIG. 2 is a top view of the pole piece of FIG. 1 provided in an embodiment of the present application;
fig. 3 is a schematic view of a part of a structure of a pole piece provided in an embodiment of the present application, where fig. 3 shows a state when the pole piece is not provided with a first filling layer and a second filling layer;
fig. 4 is an enlarged schematic structural view at a of a part of the structure of the pole piece of fig. 3 according to an embodiment of the present application;
FIG. 5 is a top view of a portion of the structure of the pole piece of FIG. 3 provided in an embodiment of the present application;
fig. 6 is a schematic structural diagram of a pole piece provided in an embodiment of the present application;
FIG. 7 is an enlarged schematic view of the structure at B of the pole piece of FIG. 6 provided in an embodiment of the present application;
fig. 8 is a top view of a portion of the structure of the pole piece of fig. 6 provided in an embodiment of the present application.
Reference numerals illustrate:
10. a current collector;
11. a first conductive layer; 111. a first surface; 1111. a first coating zone; 1112. a first blank area;
12. an insulating layer;
13. a second conductive layer; 131. a second surface; 1311. a second coating zone; 1312. a second blank area;
20. a first active material layer;
30. a conductive structure;
31. a first conductive sheet; 311. a first body portion; 312. a first connection portion; 3121. a first solder printing; 3122. welding the through holes; 3123. welding grooves;
32. a second conductive sheet; 321. a second body portion; 322. a second connecting portion;
40. a first filler layer;
50. a first insulating structure;
60. a second filler layer;
70. a second active material layer;
80. a second insulating structure;
90. pole pieces.
Specific embodiments thereof have been shown by way of example in the drawings and will herein be described in more detail. These drawings and the written description are not intended to limit the scope of the inventive concepts in any way, but to illustrate the concepts of the present application to those skilled in the art by reference to specific embodiments.
Detailed Description
Embodiments of the present application are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and intended for the purpose of explaining the present application and are not to be construed as limiting the present application.
In the description of the present application, it should be understood that the terms "center," "longitudinal," "length," "width," "upper," "top," "bottom," "inner," "outer," and the like indicate orientations or positional relationships based on the orientation or positional relationships shown in the drawings, merely to facilitate description of the present application and simplify the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be configured and operated in a particular orientation, and are therefore not to be construed as limiting the present application.
Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In this application, unless explicitly specified and limited otherwise, the terms "mounted," "secured," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; may be mechanically connected, may be electrically connected or may be in communication with each other; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art as the case may be.
In this application, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.
In the description of the present specification, reference to the terms "optionally," "alternative embodiments," and the like, means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.
In the related art, a lithium ion battery generally includes an electric core formed by winding or laminating a pole piece and a separator. The pole piece generally comprises a current collector and a conductive structure connected with the current collector, wherein the conductive structure can form a lug structure of the battery cell after the pole piece is wound or laminated.
In the related art, in order to improve the puncture resistance and the impact resistance of the battery cell, the current collector with the metal foil structure may be replaced by a composite current collector, where the composite current collector includes an insulating layer and metal layers correspondingly disposed on the upper and lower sides of the insulating layer. When the composite current collector and the tab are welded, poor welding effects such as perforation of welding spots, overhigh protrusion of welding spots and the like often occur in actual operation due to the existence of the insulating layer, and further development and application of the composite current collector are seriously affected. On one hand, the welding point perforation can reduce the welding connection strength and the conductivity, and the normal operation of the battery is affected; on the other hand, too high a welding spot bulge can increase the risk of the separator being pierced, so that the safety performance of the battery is threatened; moreover, the junction of the composite current collector and the tab forms a weak area easily, and the composite current collector is broken or torn, so that the electric connection strength of the conductive assembly and the current collector is poor, the overall strength of the pole piece is reduced, and the normal operation of the battery is affected.
The application provides a pole piece for solve the relatively poor problem of joint strength between current collector and the utmost point ear among the correlation technique.
The pole piece provided in this embodiment is described below with reference to the accompanying drawings.
Fig. 6 is a schematic structural diagram of a pole piece provided in an embodiment of the present application, fig. 7 is an enlarged structural diagram of a pole piece B shown in fig. 6 provided in an embodiment of the present application, and fig. 8 is a top view of a part of the structure of the pole piece of fig. 6 provided in an embodiment of the present application.
As shown in fig. 6 to 8, the pole piece of the present embodiment includes a current collector 10, a first active material layer 20, a conductive structure 30, and a first filling layer 40.
Wherein the current collector 10 has first and second surfaces 111 and 131 opposite to each other in a thickness direction, the first surface 111 including a first coating region 1111 and a first blank region 1112 adjacent to the first coating region 1111; the first active material layer 20 is coated in the first coating region 1111; the conductive structure 30 includes a first conductive sheet 31, where the first conductive sheet 31 includes a first body portion 311 and a first connection portion 312 connected to the first body portion 311, and the first connection portion 312 is fixedly connected in the first blank 1112 of the current collector 10; the first filling layer 40 is disposed on a side of the first conductive sheet 31 facing away from the current collector 10, and the first filling layer 40 covers at least a portion of the first connection portion 312.
In a specific example, as shown in fig. 1 and 2, in the present embodiment, the current collector 10 is a composite current collector 10, specifically, the current collector 10 includes a first conductive layer 11, an insulating layer 12, and a second conductive layer 13 sequentially disposed in a thickness direction, a surface of the first conductive layer 11 facing away from the insulating layer 12 forms a first surface 111, and a surface of the second conductive layer 13 facing away from the insulating layer 12 forms a second surface 131.
The thicknesses of the first conductive layer 11 and the second conductive layer 13 are each between 0.3 μm and 20 μm. The thickness of the insulating layer 12 is between 1 μm and 20 μm.
In one example, the insulating layer 12 may be, for example, PP, PET, or PVC; the conductive layer may be, for example, a copper layer or an aluminum layer. The composite current collector may be formed by vapor deposition or electroplating on the insulating layer 12 to form a first conductive layer or a second conductive layer; alternatively, the first conductive layer or the second conductive layer may be bonded to the insulating layer 12 by means of an adhesive.
The pole piece of the embodiment includes a current collector 10 and a first conductive sheet 31 fixedly connected to the current collector 10, the first conductive sheet 31 includes a first main body portion 311 and a first connection portion 312 connected to the first main body portion 311, and the first conductive sheet 31 is fixedly connected to the current collector 10 through the first connection portion 312. The first conductive sheet is arranged on the current collector and connected with the electrode lug, so that the electric connection between the current collector and the electrode lug is not limited by the insulating layer, and the conductivity of the electrode plate is effectively improved; furthermore, a first filling layer is arranged on one side of the first conducting strip, which is far away from the current collector, and at least part of the first connecting part is covered by the first filling layer, namely, the connecting part between the first conducting strip and the current collector is reinforced by the first filling layer, and meanwhile, the first conducting strip and the current collector are bonded together by the first filling layer, so that the connecting strength between the first conducting strip and the current collector is effectively ensured, the overall stability of the pole piece is improved, and the fault or tearing of the composite current collector of the first connecting part is prevented; in addition, the first filling layer can prevent the protrusion formed by the first connecting part from penetrating through the diaphragm and contacting with the other pole piece, thereby causing short circuit; and the first filling layer can also fill the perforation possibly existing in the first connecting part, so that the structural strength of the pole piece is ensured.
In the present embodiment, the first conductive sheet 31 is an integrally formed structure.
The first filling layer 40 may be provided as a conductive adhesive layer in order to enhance the conductive performance of the electrode sheet, which is limited by the influence of the connection process and also easily causes a decrease in the conductive performance at the connection of the first conductive sheet 31 and the current collector 10. This arrangement can increase the connection strength of the connection between the first conductive sheet 31 and the current collector 10, and can also increase the conductivity of the connection between the first conductive sheet 31 and the current collector 10, thereby reducing the internal resistance of the electrode sheet.
Specifically, the conductive adhesive may be extruded onto the first connection portion 312 through the dispensing head, and then flattened by the pressing roller, and the conductive adhesive layer is formed after the conductive adhesive is air-dried.
In the rolling process of the pole piece, the pressure range of the press roller is between 1Kg and 40Kg, the width range of the rolling area of the press roller is between 0.1mm and 15mm, and the press roller only rolls the area coated with the conductive adhesive.
The conductive adhesive layer adheres the structure at the first connection portion 312 by structural force, thereby being capable of reinforcing the strength at the first connection portion 312. Meanwhile, the conductive adhesive layer can also shield the first connecting portion 312, and the thickness of the pole piece at the first connecting portion 312 is increased, so that the strength of the first connecting portion 312 is improved.
The conductive adhesive comprises a resin matrix, conductive filler, a dispersing additive, an auxiliary agent and the like. Wherein the resin matrix is selected from at least one of adhesives such as epoxy resin, organic silicon resin, polyimide resin, phenolic resin, polyurethane, acrylic resin and the like.
The conductive filler is selected from at least one of carbon, metal and metal oxide. The carbon-based filler is at least one selected from carbon black, graphite, and the like. The metal filler is selected from at least one of gold, silver, copper, aluminum, zinc, iron, nickel powder and graphite and some conductive compounds.
Further, in the present embodiment, the first connection portion 312 is connected to the current collector 10 by welding, and the first connection portion 312 has the first welding 3121 thereon.
Fig. 3 is a schematic view of a part of a structure of a pole piece provided in an embodiment of the present application, where fig. 3 shows a state when the pole piece is not provided with a first filling layer and a second filling layer; fig. 4 is an enlarged schematic structural view at a of a part of the structure of the pole piece of fig. 3 according to an embodiment of the present application; fig. 5 is a top view of a portion of the structure of the pole piece of fig. 3 provided in an embodiment of the present application.
As shown in fig. 3 to 5, before the first filling layer 40 and the second filling layer 60 are not provided, that is, before the conductive adhesive layer is not coated, the surface of the first solder 3121 is easily formed into a rugged structure under the influence of the soldering process, and if the height of the protrusion is too high, the risk of the separator being pierced during the winding or lamination of the battery cell increases.
In this embodiment, the first filling layer 40 is provided, and the first solder mask 3121 is covered by the first filling layer, so that the protruding portion on the surface of the first solder mask 3121 is shielded, the recessed portion is filled, the surface of the pole piece is smoother, and the risk of the diaphragm being pierced is reduced.
Specifically, the first conductive sheet 31 and the current collector 10 are welded by means of roll welding, after the roll welding, the first welding stamp 3121 may leave protrusions and recesses, the recesses include a welding groove 3123 and a welding through hole 3122, the welding groove 3123 refers to a recess which does not penetrate the pole piece, the welding through hole 3122 refers to a recess which penetrates the current collector 10 and the conductive structure 30 in the thickness direction of the pole piece, and these recesses may reduce the conductivity of the hard pole piece and increase the internal resistance of the pole piece.
In this embodiment, the conductive adhesive is coated on the first connection portion 312, and is spread and tiled by the pressing roller to fill the conductive adhesive into the concave portion, and after the conductive adhesive is air-dried, the first filling layer 40 extending into the welding through hole 3122 and the welding groove 3123 is formed, so that the overpower capability of the pole piece is effectively ensured, and the internal resistance of the pole piece is reduced. It should be noted that, in order to further increase the conductivity of the electrode sheet, in some embodiments, the proportion of the solder through hole 3122 may be 10% to 30% of the total number of the recesses by adjusting the process parameters of the soldering. After the conductive paste is coated on the first connection portion 312, the first conductive sheet 31 and the second conductive sheet 32 may be conducted through the conductive paste, thereby increasing the conductive performance of the electrode sheet.
Specifically, the proportion of the solderable through holes 3122 accounts for 10%, 15%, 20%, 25%, and 30% of the total number of recesses.
It should be noted that the state in which the recess includes only the welding groove or only the welding through hole may be achieved by adjusting the welding parameters. In the case where the recess includes only the welding through holes, care should be taken to control the number of welding through holes in order to prevent the number of welding through holes from excessively affecting the strength of the pole piece.
In addition, after filling the conductive paste, it should be ensured that the unfilled diameter of the individual recesses is less than 5mm. Preferably, the unfilled diameter of the recess is made 0mm, i.e. the recess is completely blocked by the conductive glue.
Further, the boundary of the first filling layer 40 at least partially coincides with the boundary of the first connecting portion 312. Specifically, the first filling layer 40 completely covers the first solder 3121, and the boundary of the first filling layer 40 is flush with the boundary of the conductive structure 30. The width of the first filler layer 40 is between 0.1mm and 15 mm.
In other embodiments, the first filling layer 40 may cover only a portion of the first solder 3121.
As shown in fig. 3 and 6, in the present embodiment, the pole piece further includes a first insulating structure 50, the first insulating structure 50 being disposed in the first space 1112 of the current collector 10, the first insulating structure 50 being capable of separating the first active material layer 20 and the first conductive sheet 31.
Specifically, in this embodiment, the first insulating structure 50 includes a ceramic insulating strip bonded to the first void region 1112. The ceramic insulating strip has the advantages of high chemical stability and high thermal stability.
The thickness of the first insulating structure 50 is between 1 μm and 100 μm, so that the first insulating structure 50 can perform good insulation, and the first active material layer 20 and the first conductive sheet 31 have the effect. In addition, the first insulating structure 50 can also play a certain limiting role on the conductive adhesive.
It should be further noted that the first connection portion 312 is disposed at an edge of the first conductive sheet 31 near the ceramic insulating strip.
Further, the distance between the first insulating structure 50 and the first filling layer 40 is greater than or equal to 0mm, and the distance between the ceramic insulating strip and the first filling layer 40 may be 0, that is, the ceramic insulating strip is disposed closely to the first filling layer 40. Of course, a gap may be provided between the ceramic insulating strip and the first filler layer 40 to ensure that the first active material layer 20 and the first conductive sheet 31 are insulated.
Specifically, the thickness of the first insulating structure 50 may be any value between 1 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, or 1 μm to 100 μm.
Further, the thickness of the first conductive sheet 31 is between 1 μm and 20 μm. The first conductive sheet 31 needs to be light in weight and have a connection strength, and the smaller the thickness of the first conductive sheet 31 is, the lighter the mass is, but the weaker the strength after welding is, whereas the larger the thickness of the first conductive sheet 31 is, the larger the mass is, but the strength after welding is improved. The thickness of the first conductive sheet 31 is in the range of 1 μm to 20 μm, and the weight reduction and the connection strength of the first conductive sheet 31 can be both achieved.
Specifically, the thickness of the first conductive sheet 31 may be any value between 1 μm, 5 μm, 10 μm, 15 μm, 20 μm, or 1 μm to 20 μm.
Further, the thickness of the first filler layer 40 is between 2 μm and 200 μm. The greater the thickness of the first filler layer 40, the greater the strength of the pole piece, but the corresponding increase in production costs. The more effective the thickness of the first filling layer 40, the weaker the filling effect on the first solder 3121, and the smoothness of the first solder 3121 and the connection strength of the first connection portion 312 may be reduced. Setting the thickness of the first filler layer 40 between 2 μm and 200 μm thus helps balance production costs and strength and safety of the pole piece.
Specifically, the thickness of the first filling layer 40 may be any value between 2 μm, 10 μm, 20 μm, 35 μm, 50 μm, 70 μm, 90 μm, 100 μm, 120 μm, 150 μm, 175 μm, 200 μm, or 2 μm to 200 μm.
Further, the difference between the thickness of the first filling layer 40 and the thickness of the first insulating structure 50 is between 0 μm and 5 μm. In the present embodiment, the thickness of the first insulating structure 50 is greater than that of the first filling layer 40, and the difference between the thicknesses is controlled to be less than 5 μm. In other embodiments, the thickness of the first filling layer 40 may be greater than that of the first insulating structure 50, and the difference between the thicknesses is controlled to be less than 5 μm. Alternatively, in other embodiments, the thickness of the first filling layer 40 may be greater than the same thickness of the first insulating structure 50.
Fig. 1 is a schematic view of a part of a structure of a pole piece provided in an embodiment of the present application, in which fig. 1 shows a structure after a first active material layer and a second active material layer are coated on a current collector, and fig. 2 is a top view of a part of a structure of a pole piece provided in an embodiment of the present application.
As shown in fig. 1, 3 and 6, in the present embodiment, the second surface 131 includes a second coating region 1311 and a second blank region 1312 connected to the second coating region 1311; the conductive structure 30 further includes a second conductive sheet 32, where the second conductive sheet 32 includes a second body portion 321 and a second connection portion 322 connected to the second body portion 321, and the second connection portion 322 is fixedly connected in the second blank area 1312 of the current collector 10.
The second conductive sheet 32 has the same structure and functions as the first conductive sheet 31.
As shown in fig. 1, 3 and 6, the pole piece in this embodiment further includes: a second filler layer 60. The second filling layer 60 is disposed on a side of the second conductive sheet 32 facing away from the current collector 10, and the second filling layer 60 covers at least part of the connection portion of the second conductive sheet 32.
Specifically, the second conductive sheet 32 is welded on the current collector 10 by adopting a roll welding mode, a second welding mark is formed on the second conductive sheet 32, the second welding mark is provided with a concave part and the surface is uneven, the second filling layer 60 is a conductive adhesive layer, the effect of the second filling layer 60 is the same as that of the first filling layer 40, the connection strength between the second conductive sheet 32 and the current collector 10 can be improved, the smoothness of the second conductive sheet 32 is improved, the risk that a pole piece pierces a diaphragm is reduced, the concave part can be filled, and the conductivity of the pole piece is further improved.
As shown in fig. 1, 3 and 6, the pole piece in this embodiment further comprises a second active material layer 70 and a second insulating structure 80.
The second active material layer 70 is coated in the second coating region 1311.
The second insulating structure 80 is disposed in the second blank 1312 of the current collector 10, and the second insulating structure 80 separates the second active material layer 70 and the second conductive sheet 32 to function as an insulation between the second active material layer 70 and the second conductive sheet 32.
Preferably, the second insulating structure 80 is a ceramic insulating strip.
The present application also provides a battery cell (not shown in the drawings), where an embodiment of the battery cell of the present application includes: the first pole piece, the second pole piece and the diaphragm arranged between the first pole piece and the second pole piece.
Specifically, the first pole piece, the second pole piece and the diaphragm are wound or laminated to form; the first pole piece is the pole piece 90, and the conductive structure 30 of the first pole piece forms a tab structure of the battery cell.
In this embodiment, the first electrode sheet is a positive electrode sheet, and the first active material layer 20 and the second active material layer 70 of the first electrode sheet are positive electrode active material layers.
The second electrode sheet is a negative electrode sheet, and the structure thereof is the same as the first electrode sheet, except that the first active material layer 20 and the second active material layer 70 are negative electrode active material layers.
The first pole piece, the diaphragm and the second pole piece are wound or laminated to form a battery core, the conductive structure 30 of the first pole piece forms a positive pole lug (positive soft lug) of the battery core, the positive pole lug can be connected with a hard lug, and the positive pole lug is connected with a positive pole post of the battery through the hard lug.
Correspondingly, the conductive structure 30 of the second pole piece is wound or laminated to form a negative pole tab (negative soft tab), and the negative pole tab can be connected with a hard tab, and is connected with a negative pole post of the battery through the hard tab.
The electrode plate has the advantages of high strength, good safety and good conductivity, so the battery cell with the electrode plate also has the advantages.
The application also provides a battery (not shown in the figure), and the embodiment of the battery of the application comprises a battery cell, wherein the battery cell is the battery cell. The battery cell has the advantages of high strength, good safety and good conductivity, so that the battery with the battery cell also has the advantages.
Finally, it should be noted that: the above embodiments are merely for illustrating the technical solution of the present application, and are not limiting thereof; 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 scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced with equivalents; such modifications and substitutions do not depart from the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims (8)

1. A pole piece, comprising:
a current collector (10), the current collector (10) having a first surface (111) and a second surface (131) opposite to each other in a thickness direction, the first surface (111) including a first coating region (1111) and a first blank region (1112) adjacent to the first coating region (1111);
a first active material layer (20) coated within the first coating zone (1111);
the conductive structure (30) comprises a first conductive sheet (31), wherein the first conductive sheet (31) comprises a first main body part (311) and a first connecting part (312) connected with the first main body part (311), and the first connecting part (312) is fixedly connected in the first blank area (1112);
a first filling layer (40) disposed on a side of the first conductive sheet (31) facing away from the current collector (10), the first filling layer (40) covering at least a portion of the first connection portion (312);
the first filling layer (40) is a conductive adhesive layer;
the first connecting part (312) is connected with the current collector (10) through welding, a first welding mark (3121) is arranged on the first connecting part (312), and the first filling layer (40) covers the first welding mark (3121);
-the first solder print (3121) comprises a bump, the first filling layer (40) covering the bump;
the first welding stamp (3121) further comprises a recess comprising a welding through hole (3122) and a welding groove (3123), the welding through hole (3122) penetrating the current collector (10) and the conductive structure (30) in the thickness direction of the pole piece, the first filling layer (40) extending into the recess, the proportion of the welding through hole (3122) being 10% to 30% of the total number of the recess;
the thickness of the first filling layer (40) is between 2 and 200 μm;
-the boundary of the first filling layer (40) is flush with the boundary of the first connection (312);
the pole piece further comprises:
a first insulating structure (50) disposed within a first empty region (1112) of the current collector (10), the first insulating structure (50) separating the first active material layer (20) and the first conductive sheet (31);
-the difference between the thickness of the first filling layer (40) and the thickness of the first insulating structure (50) is between 0 μm and 5 μm;
the distance between the first insulating structure (50) and the first filling layer (40) is equal to 0mm.
2. The pole piece of claim 1, wherein the first insulating structure (50) comprises a ceramic insulating strip bonded to the first void region (1112).
3. The pole piece according to any of the claims 1 to 2, characterized in that,
the thickness of the first insulating structure (50) is between 1 μm and 100 μm;
and/or the thickness of the first conductive sheet (31) is between 1 μm and 20 μm.
4. A pole piece as claimed in claim 1, wherein,
the distance from the first solder mask (3121) to the edge of the first conductive sheet (31) on the side close to the first insulation structure (50) is smaller than the distance from the first solder mask (3121) to the side of the first conductive sheet (31) away from the first insulation structure (50).
5. Pole piece according to claim 1, characterized in that the current collector (10) comprises a first conductive layer (11), an insulating layer (12) and a second conductive layer (13) arranged in sequence in the thickness direction, the surface of the first conductive layer (11) facing away from the insulating layer (12) forming the first surface (111) and the surface of the second conductive layer (13) facing away from the insulating layer (12) forming the second surface (131).
6. The pole piece of claim 2, wherein the second surface (131) comprises a second coated region (1311) and a second blank region (1312) connected to the second coated region (1311); the conductive structure (30) further comprises a second conductive sheet (32), the second conductive sheet (32) comprises a second main body part (321) and a second connecting part (322) connected with the second main body part (321), and the second connecting part (322) is fixedly connected in the second blank area (1312) of the current collector (10);
the pole piece further comprises:
a second filling layer (60) disposed on a side of the second conductive sheet (32) facing away from the current collector (10), the second filling layer (60) covering at least a portion of the second connection portion (322);
a second active material layer (70) coated within the second coating region (1311);
and a second insulating structure (80) disposed in a second blank region (1312) of the current collector (10), the second insulating structure (80) separating the second active material layer (70) and the second conductive sheet (32).
7. A battery cell, wherein the battery cell comprises: a first pole piece, a second pole piece, and a diaphragm disposed between the first pole piece and the second pole piece, the first pole piece, the second pole piece, and the diaphragm being wound or laminated; wherein,
the first pole piece is a pole piece (90) according to any one of claims 1 to 6, the conductive structure (30) of the first pole piece forming a tab structure of the battery cell.
8. A battery, comprising:
a battery cell, said battery cell being according to claim 7.
CN202311498849.1A 2023-11-13 2023-11-13 Pole piece, battery cell and battery Active CN117239058B (en)

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