WO2024021868A1

WO2024021868A1 - Battery core structure and battery

Info

Publication number: WO2024021868A1
Application number: PCT/CN2023/098401
Authority: WO
Inventors: 徐腾飞; 杨赛男; 谢继春
Original assignee: 珠海冠宇电池股份有限公司
Priority date: 2022-07-27
Filing date: 2023-06-05
Publication date: 2024-02-01
Also published as: CN217933932U

Abstract

Provided in the present application are a battery core structure and a battery. The battery core structure comprises a first electrode sheet, a separator and a second electrode sheet, which are sequentially laminated and wound, wherein the second electrode sheet is positioned on an outer side, and comprises a composite current collector, an active material layer and a tab. The composite current collector has a first metal surface and a second metal surface, which are opposite each other, wherein part of the first metal surface is coated with the active material layer, and part of the second metal surface is coated with the active material layer, such that a double-sided coated area, a single-sided coated area and a blank area are formed on the composite current collector; and one of the first metal surface and the second metal surface has a first welding portion, and the tab is welded to the first welding portion and is opposite the single-sided coated area or the blank area. In the battery core structure provided in the present application, the second electrode sheet is arranged on the outer side, and the tab is arranged on the second electrode sheet, such that the first metal surface and the second metal surface of the composite current collector can be directly electrically connected, and thus the thickness of a battery is reduced.

Description

Cell structure and battery

This application claims priority to the Chinese patent application filed with the China Patent Office on July 27, 2022, with the application number 202221957247.9 and the application name "Battery Cell Structure and Battery", the entire content of which is incorporated into this application by reference.

Technical field

The present application relates to the field of battery technology, and in particular, to a battery core structure and a battery.

Background technique

A lithium-ion battery includes a separator and two pole pieces. The two pole pieces have opposite polarities. The separator is located between the two pole pieces. The two pole pieces and the separator are stacked and wound in sequence to form a cell structure.

The pole piece includes a current collector and an active material layer, and the active material layer is coated on both sides of the current collector. Among them, the current collector collects the electrons generated by the chemical reaction, and the tabs are welded to the current collector, and the tabs conduct the electrons to the external circuit. In order to improve the energy density and safety of the battery, a composite current collector can be used as a current collector. The composite current collector includes a polymer film and metal coatings on both sides of the polymer film. The insulation of the polymer film makes the metal coatings on both sides conductive. If the continuity is affected, usually one tab is welded to the metal coating on both sides of the polymer film, and then the two tabs are electrically connected to achieve conduction of the metal coating on both sides of the polymer film.

However, welding tabs to the metal plating on both sides of the polymer film will increase the thickness of the battery.

Contents of the invention

This application provides a battery core structure and a battery. By arranging the second pole piece on the outside and arranging a tab on the second pole piece, the first metal surface and the second metal surface in the composite current collector can be directly electrically connected. , thus, the thickness of the battery can be reduced.

The present application provides an electric core structure, which includes a first pole piece, a separator and a second pole piece that are stacked and wound in sequence. The second pole piece is located on the outside. The second pole piece includes a composite current collector, an active material layer and a tab. , the composite current collector has a first metal surface and a second metal surface opposite to each other, and part of the first metal surface The surface is coated with an active material layer, and part of the second metal surface is covered with the active material layer to form a double-sided coating area, a single-sided coating area and a blank area on the composite current collector;

There is a first welding part on one of the first metal surface and the second metal surface, and the tab is welded on the first welding part, and the tab is opposite to the single-sided coating area or the blank area, and the tab is used to electrically connect the third a metal surface and a second metal surface.

In a possible implementation, in the battery core structure provided by this application, the first welding part is located on the first metal surface, and the first welding part is located in the single-sided coating area, and the active material layer includes the first active material layer, The first active material layer is located on the first metal surface.

In a possible implementation, in the battery core structure provided by this application, the distance between the first welding part and the first active material layer is less than or equal to half the length of the single-sided coating area.

In a possible implementation, in the battery core structure provided by this application, the first welding part is located on the second metal surface, and the first welding part is located in the blank area, the active material layer includes a second active material layer, and the second active material layer The material layer is located on the second metal surface.

In a possible implementation, in the battery core structure provided by this application, the distance between the first welding part and the second active material layer is less than or equal to half the length of the single-sided coating area.

In a possible implementation, in the battery core structure provided by this application, the second active material layer includes a first active material segment and a second active material segment, the first active material segment, the first welding part and the second active material The segments are spaced apart in sequence on the second metal surface.

In a possible implementation, in the battery core structure provided by this application, one of the first metal surface and the second metal surface of the second pole piece has a second welding part, the first welding part and the second welding part. One of the parts is located on the first metal surface, and the other of the first welding part and the second welding part is located on the second metal surface;

The second welding part overlaps with the projection of the first welding part on the second pole piece, and the tab of the second pole piece is welded to the second welding part to electrically connect the first metal surface and the second metal surface.

In a possible implementation, in the battery core structure provided by this application, the distance between the center of the first welding part and the center of the second welding part is greater than or equal to 0 and less than or equal to two-thirds of the tab. width.

In a possible implementation, in the battery core structure provided by this application, both the first metal surface and the second metal surface of the second pole piece have second welding parts, and the two second welding parts are on the second pole piece. The projections overlap, and the two second welding parts are welded.

In a possible implementation, the battery core structure provided by the present application further includes an insulating glue layer, and the insulating glue layer covers the side of the tab on the second pole piece facing the first pole piece.

This application also provides a battery, including a casing and the above-mentioned battery core structure, and the battery core structure is arranged in the casing.

This application provides a battery core structure and a battery. The battery core structure includes a first pole piece, a separator and a second pole piece that are stacked and wound in sequence. The second pole piece is located on the outside. The second pole piece includes a composite current collector and an active material. layer and tab, the composite current collector has a first metal surface and a second metal surface opposite each other, part of the first metal surface is coated with an active material layer, and part of the second metal surface is covered with the active material layer, so as to form a layer on the composite current collector. A double-sided coating area, a single-sided coating area and a blank area are formed; one of the first metal surface and the second metal surface has a first welding portion, and before the cell structure is wound, one side of the tab is connected to the first welding portion. A welding part is welded to be electrically connected to one of the first metal surface and the second metal surface. After the battery core structure is wound, by disposing the second pole piece on the outside, the single-sided coating on the first metal surface is The covered area or blank area is opposite to the other side of the tab to facilitate electrical connection with the tab; or the blank area on the second metal surface is opposite to the other side of the tab to facilitate electrical connection with the tab; or the first metal The surface and the second metal surface are directly electrically connected, whereby the first metal surface and the second metal surface can be directly electrically connected through a tab to bring together the electrons in the first metal surface and the second metal surface, Compared with the existing technology that requires two metal surfaces of the composite current collector to be electrically connected through two tabs, the thickness of the battery can be reduced.

Description of drawings

In order to more clearly explain the embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description These are some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without exerting creative efforts.

Figure 1 is a schematic structural diagram of the battery core structure provided by the embodiment of the present application;

Figure 2 is another structural schematic diagram of the battery core structure provided by the embodiment of the present application;

Figure 3 is a first structural schematic diagram of the second pole piece in the battery core structure provided by the embodiment of the present application;

Figure 4 is a second structural schematic diagram of the second pole piece in the battery core structure provided by the embodiment of the present application;

Figure 5 is a third structural schematic diagram of the second pole piece in the battery core structure provided by the embodiment of the present application;

Figure 6 is an enlarged view of point A in Figure 1;

Figure 7 is another enlarged view of position A in Figure 1;

Figure 8 is a schematic structural diagram of the tabs in the battery core structure provided by the embodiment of the present application;

Figure 9 is an enlarged view of point B in Figure 2.

Explanation of reference symbols:
100-cell structure;
110-First pole piece;
120-diaphragm;
130-Second pole piece;
131-composite current collector; 131a-double-sided coating area; 131b-single-sided coating area; 131c-blank area;
1311-first metal surface; 1312-second metal surface; 1313-first welding part; 1314-insulation layer; 1315-second welding part;
132-active material layer; 1321-first active material layer; 1322-second active material layer; 1322a-
The first active material segment; 1322b-the second active material segment;
133-pole lug; 1331-third welding part; 1332-fourth welding part;
134-Insulating adhesive layer;
L-length of single-sided coating area;
L1-first spacing;
L2-the second distance;
L3-third distance;
W - pole lug width;
S-starting end;
E-tail.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments These are part of the embodiments of this application, but not all of them. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of this application.

In the description of this application, it should be noted that, unless otherwise expressly provided and limited, the term The words "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection or an indirect connection through an intermediate medium. It can be an internal connection between two components or an interactive relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "vertical", "horizontal", "top", "bottom", "inner", The orientation or positional relationship indicated by "outside" is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or component referred to must have a specific orientation. Constructed and operated in a specific orientation and therefore should not be construed as limiting this application.

The terms "first", "second" and "third" (if present) in the description and claims of this application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific sequence or sequence. Sequence. It is to be understood that the data so used are interchangeable under appropriate circumstances so that the embodiments of the application described herein can, for example, be practiced in sequences other than those illustrated or described herein.

Furthermore, the terms "include" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or maintenance tool that encompasses a series of steps or units and need not be limited to those explicitly listed. may include other steps or elements not expressly listed or inherent to such processes, methods, products or maintenance tools.

Lithium-ion batteries have the advantages of high energy density, good cycle life, small self-discharge, and fast charge and discharge speed. They are widely used in energy storage, consumer electronics, aerospace, travel and transportation and other fields.

The pole piece includes a current collector and an active material layer, and the active material layer is coated on both sides of the current collector. The charging and discharging process of lithium-ion batteries is realized through the insertion and de-intercalation of lithium ions in the active material layer. Among them, the current collector collects the electrons generated by the chemical reaction, the tab is welded to the current collector, the tab is electrically connected to the current collector, and the tab conducts the electrons to the external circuit.

In order to improve the energy density and safety of the battery, a composite current collector can be used as a current collector. The composite current collector includes a polymer film and metal plating on both sides of the polymer film. The polymer film layer is made of lighter weight polymer materials, so the composite current collector is heavier than the pure metal current collector. The volume is reduced by 50%-80%, and the thickness of the composite current collector is 25%-40% smaller than that of pure metal current collectors, thereby leaving more space in the battery to accommodate active materials, making batteries using composite current collectors have higher energy density. In addition, the composite current collector does not produce metal burrs when hit by heavy objects, which can prevent short circuit between the two pole pieces. Therefore, batteries using composite current collectors also have high safety.

However, the insulation of the polymer film affects the conductivity of the metal plating on both sides of the polymer film. Usually, tabs are welded to the metal plating on both sides of the polymer film, and then the tabs are electrically connected to realize the two sides of the polymer film. The metal plating on the side is conductive. Specifically, in the first method, one tab can be welded to the metal plating on both sides, and then the two tabs are welded together to electrically connect the metal plating on both sides of the composite current collector. In the second method, a through hole is provided in the composite current collector, the pole tab is passed through the through hole, and welded to the current collectors on both sides respectively to electrically connect the metal plating on both sides of the composite current collector. Both of the above methods will increase the thickness of the tabs in the battery, and the second method is easy to damage the composite current collector during actual operation, making the operation more difficult.

Based on this, the present application provides a battery core structure and a battery. By arranging the second pole piece on the outside and arranging a tab on the second pole piece, the first metal surface and the third metal surface in the composite current collector can be directly electrically connected. Two metal surfaces, thus, the thickness of the battery can be reduced.

The lithium-ion battery includes a casing and a cell structure 100, and the cell structure 100 is disposed in the casing. The case is used to encapsulate the cell structure 100. In order to reduce the weight of the lithium-ion battery, the case can be made of aluminum alloy.

Figure 1 is a schematic structural diagram of the battery core structure provided by the embodiment of the present application; Figure 2 is another structural schematic diagram of the battery core structure provided by the embodiment of the present application; Figure 3 is a second pole in the battery core structure provided by the embodiment of the present application. The first structural schematic diagram of the chip; Figure 4 is the second structural schematic diagram of the second pole piece in the battery core structure provided by the embodiment of the present application; Figure 5 is the second structural schematic diagram of the second pole piece in the battery core structure provided by the embodiment of the present application. Schematic diagram of the third structure.

Referring to FIGS. 1 to 5 , the battery core structure 100 includes a first pole piece 110 , a separator 120 and a second pole piece 130 that are stacked and wound in sequence. The second pole piece 130 is located on the outside. The second pole piece 130 includes a composite Current collector 131, active material layer 132 and tab 133. Composite current collector 131 has opposite first metal surface 1311 and second metal surface 1312. Part of first metal surface 1311 is coated with active material layer 132, part of second metal The active material layer 132 is covered on the surface 1312 to form a double-sided coating area 131a, a single-sided coating area 131b and a blank area 131c on the composite current collector 131; one of the first metal surface 1311 and the second metal surface 1312 Having the first weld on part 1313, and the tab 133 is welded to the first welding part 1313. The tab 133 is opposite to the single-sided coating area 131b or the blank area 131c. The tab 133 is used to electrically connect the first metal surface 1311 and the second metal surface 1312.

Please continue to refer to Figures 1 and 2. The cell structure 100 is an electrochemical cell containing positive and negative electrodes installed in the casing. The cell structure 100 is the power storage part of the lithium-ion battery. One of the first pole piece 110 and the second pole piece 130 is used as the positive electrode of the battery core structure 100 , and the other one is used as the negative electrode of the battery core structure 100 . The separator 120 serves as electronic insulation between the first pole piece 110 and the second pole piece 130 and provides a microporous channel for lithium ion migration. Electrolyte is also injected into the cell structure 100, and the charging and discharging process of the lithium-ion battery is realized by the insertion and de-intercalation of lithium ions through the electrolyte on the first pole piece 110 and the second pole piece 130.

At the end of the winding, the first pole piece 110 is located on the inside. The first pole piece 110 adopts a structure known in the art. The structure of the first pole piece 110 will not be described in this embodiment. The second pole piece 130 is located on the outside. , that is to say, the second pole piece 130 is located in the outermost circle of the stacked winding structure of the battery core structure 100 for finishing the battery core structure 100 .

Next, the structure of the second pole piece 130 will be described in detail.

Please continue to refer to FIGS. 3 to 5 . The second pole piece 130 includes a current collector, an active material layer 132 and a tab 133 . Lithium ions can be embedded and deintercalated in the active material layer 132 . Lithium ions can be embedded and deintercalated in the active material layer 132 . When electrons are generated, the current collector is used to collect the generated electrons, and the tabs 133 are used to connect with the external circuit, and conduct the electrons to the external circuit through the tabs 133.

In this embodiment, the current collector is a composite current collector 131. The composite current collector 131 includes an insulating layer 1314 and a first metal surface 1311 and a second metal surface 1312 located on both sides of the insulating layer 1314. The insulating layer 1314 prevents the first metal surface 1311 and the second metal surface 1312 from being connected, so that the electrons in the first metal surface 1311 and the second metal surface 1312 cannot be brought together. In this embodiment, the first metal surface 1311 and the second metal surface 1312 can be connected through a tab 133. The process of connecting the first metal surface 1311 and the second metal surface 1312 through a tab 133 will be described below. .

Please continue to refer to FIG. 3 to FIG. 5 , the active material layer 132 is coated on part of the first metal surface 1311 , the active material layer 132 is covered on part of the second metal surface 1312 , and the active material layer 132 on the first metal surface 1311 The coverage length is different from the coverage length of the active material layer 132 on the second metal surface 1312, so as to form a double-sided coating area 131a on the composite current collector 131. Single-sided coated area 131b and blank area 131c. The double-sided coating area 131a refers to the active material layer 132 coated on both the first metal surface 1311 and the second metal surface 1312, and the single-sided coating area 131b refers to the first metal surface 1311 and the second metal surface 1312. The active material layer 132 is coated on one of the first metal surfaces 1311 and the second metal surface 1312 , and the blank area 131 c means that no active material layer 132 is coated on either the first metal surface 1311 or the second metal surface 1312 . It should be noted that the double-sided coating area 131a is generally provided at the starting end S of the winding, and the blank area 131c is generally provided at the end end E of the winding for finishing the battery core structure 100. Among them, for the sake of clarity, only the double-sided coating area 131a, the single-sided coating area 131b and the blank area 131c are identified in FIG. 3 .

Please continue to refer to FIG. 3 . In the first implementation manner, the area on the first metal surface 1311 that is not coated with the active material layer 132 (single-sided coating area 131b or blank area 131c) is located close to the tail end E. A welding part 1313 can be disposed in this area, and one side of the tab 133 is welded to the first welding part 1313. The tab 133 is electrically connected to the first metal surface 1311. After the battery core structure 100 is wound, the tab 133 The other side of the tab 133 will be opposite and in contact with the area (blank area 131c) on the second metal surface 1312 that is not coated with the active material layer 132, and then the other side of the tab 133 is electrically connected to the second metal surface 1312, so that the first metal The electrons in the surface 1311 and the second metal surface 1312 are gathered together, and are conducted to the external circuit through the tab 133 .

Please continue to refer to FIG. 4 . In the second implementation manner, the area (blank area 131 c ) that is not coated with the active material layer 132 on the second metal surface 1312 is located close to the tail end E of the composite current collector 131 . The first welding Part 1313 is disposed in this area, and one side of the tab 133 is welded to the first welding part 1313. The tab 133 is electrically connected to the second metal surface 1312. After the battery core structure 100 is wound, the other side of the tab 133 It will be opposite and in contact with the area (single-sided coating area 131b or blank area 131c) on the first metal surface 1311 that is not coated with the active material layer 132, and then the other side of the tab 133 is electrically connected to the first metal surface 1311. This causes the electrons in the first metal surface 1311 and the second metal surface 1312 to gather together, and conduct the electrons to the external circuit through the tab 133 .

In addition, please continue to refer to Figure 5. In the third implementation, a blank area 131c is also provided in the middle area of the composite current collector 131, and the first welding portion 1313 is provided on the second metal surface in the blank area 131c. 1312, one side of the tab 133 is welded to the first welding part 1313, and the tab 133 is electrically connected to the second metal surface 1312. After the battery core structure 100 is wound, the other side of the tab 133 is not connected to the first metal surface. The surface 1311 contacts, but is close to the tail end of the composite current collector 131 The second metal surface 1312 at E is in contact with the first metal surface 1311, electrically connecting the first metal surface 1311 and the second metal surface 1312 at the contact position, so that the electrons in the first metal surface 1311 and the second metal surface 1312 converge. together, and conduct electrons to the external circuit through the tabs 133 electrically connected to the first metal surface 1311.

The battery core structure 100 provided by the embodiment of the present application includes a first pole piece 110, a separator 120, and a second pole piece 130 that are stacked and wound in sequence. The second pole piece 130 is located on the outside, and the second pole piece 130 includes a composite current collector. 131. Active material layer 132 and tab 133. The composite current collector 131 has an opposing first metal surface 1311 and a second metal surface 1312. Part of the first metal surface 1311 is coated with the active material layer 132, and part of the second metal surface 1312 The active material layer 132 is covered on the composite current collector 131 to form a double-sided coating area 131a, a single-sided coating area 131b and a blank area 131c; one of the first metal surface 1311 and the second metal surface 1312 has The first welding part 1313, before the battery core structure 100 is wound, one side of the tab 133 is welded to the first welding part 1313 to be electrically connected to one of the first metal surface 1311 and the second metal surface 1312. After the core structure 100 is wound, by arranging the second pole piece 130 on the outside, the single-sided coating area 131b or the blank area 131c on the first metal surface 1311 is opposite to the other side of the pole tab 133 so as to facilitate contact with the pole tab 133 Electrical connection; or the blank area 131c on the second metal surface 1312 is opposite to the other side of the tab 133 to facilitate electrical connection with the tab 133; or the first metal surface 1311 and the second metal surface 1312 are directly electrically connected; thus , the first metal surface 1311 and the second metal surface 1312 can be directly electrically connected through one tab 133 to bring the electrons in the first metal surface 1311 and the second metal surface 1312 together. Compared with the need in the prior art, By electrically connecting the two metal surfaces of the composite current collector with the two tabs, the thickness of the battery can be reduced.

Next, the specific position of the first welding portion 1313 on the first metal surface 1311 in the first implementation manner will be described.

Please continue to refer to FIG. 3. The first welding part 1313 is located on the first metal surface 1311, and the first welding part 1313 is located in the single-sided coating area 131b. The active material layer 132 includes a first active material layer 1321. The material layer 1321 is located on the first metal surface 1311.

The active material layer 132 located on the first metal surface 1311 is called the first active material layer 1321, and the active material layer 132 located on the second metal surface 1312 is called the second active material layer 1322. The first active material layer 1321 covers The length is set smaller than the covering length of the second active material layer 1322 . Since the coverage length of the first active material layer 1321 is smaller than that of the second active material layer The coverage length of 1322 is, therefore, the first welding portion 1313 can be located on the single-sided coating area 131b on the first metal surface 1311, and the first welding portion 1313 can also be located on the blank area 131c.

In this embodiment, the first welding portion 1313 can be disposed in the single-sided coating area 131b, so that after the cell structure 100 is wound, the blank area 131c on the second metal surface 1312 can be connected with the tab 133 The other side is in contact with the first welding portion 1313 through the tab 133 .

Please continue to refer to FIG. 3 . The distance between the first welding portion 1313 and the first active material layer 1321 is less than or equal to half the length of the single-sided coating region 131 b.

Specifically, the length of the single-sided coating region 131b is called the single-sided coating region length L, and the distance between the first welding portion 1313 and the first active material layer 1321 is called the first spacing L1. When arranging the first welding part 1313, the length of the first spacing L1 is controlled so that the first spacing L1 is less than or equal to half of the length L of the single-sided coating area. Such an arrangement can make the first welding part 1313 closer to the first active material layer. 1321. The tabs 133 welded to the first welding part 1313 are also closer to the first active material layer 1321. Therefore, after the battery core structure 100 is wound, the second metal surface 1312 is close to the second active material layer 1322. The area may be in contact with the other side of tab 133. Therefore, the electrical connection between the first metal surface 1311 and the second metal surface 1312 can be achieved without providing a long blank area 131c at the tail end E.

Next, the specific position of the first welding portion 1313 on the second metal surface 1312 in the second implementation manner will be described.

Please continue to refer to FIG. 4 . The first welding part 1313 is located on the second metal surface 1312 , and the first welding part 1313 is located in the blank area 131 c . The active material layer 132 includes a second active material layer 1322 . The second active material layer 1322 Located on the second metal surface 1312.

The distance between the first welding portion 1313 and the second active material layer 1322 is less than or equal to half the length of the single-sided coating region 131b.

When the first welding portion 1313 is located on the second metal surface 1312, since the coverage length of the first active material layer 1321 is less than the coverage length of the second active material layer 1322, the first welding portion 1313 is located in the blank area 131c. The distance between the first welding portion 1313 and the second active material layer 1322 is called the second spacing L2. The second spacing L2 is less than or equal to half of the length L of the single-sided coating area. This arrangement can make the first welding portion 1313 Closer to the second active material layer 1322, the tab 133 welded to the first welding portion 1313 is also closer to the second active material layer 1322. Therefore, after the battery core structure 100 is wound, the first metal surface 1311 is closer to the second active material layer 1322. first active substance The area of the layer 1321 can be in contact with the other surface of the tab 133. Therefore, the electrical connection between the first metal surface 1311 and the second metal surface 1312 can be achieved without providing a long blank area 131c at the tail end E.

Next, the specific position of the first welding portion 1313 on the second metal surface 1312 in the third implementation manner will be described.

Please continue to refer to FIG. 5. The second active material layer 1322 includes a first active material segment 1322a and a second active material segment 1322b. The first active material segment 1322a, the first welding portion 1313 and the second active material segment 1322b are spaced apart in sequence. disposed on the second metal surface 1312.

The second active material layer 1322 can be divided into a first active material section 1322a and a second active material section 1322b arranged at intervals. The first welding portion 1313 is located between the first active material section 1322a and the second active material section 1322b. The ear 133 is welded on the first welding part.

Please continue to refer to FIG. 5. The length of the first active material layer 1321 is less than or equal to the length of the first active material segment 1322a. Therefore, there will also be formed between the first active material segment 1322a and the second active material segment 1322b. The first welding portion 1313 is provided in the blank area 131c. After the battery core structure 100 is wound, the area on the second metal surface 1312 near the tail end E is in contact with the first metal surface 1311 opposite to the tab 133. To achieve electrical connection between the first metal surface 1311 and the second metal surface 1312.

After the battery core structure 100 is wound, the electrical connection between the first metal surface 1311 or the second metal surface 1312 and the tab 133 can be achieved by crimping or welding. Below, welding will be used as an example for explanation.

Figure 6 is an enlarged view of point A in Figure 1; Figure 7 is another enlarged view of point A in Figure 1. Please continue to refer to Figures 3, 4, 6 and 7. The second pole piece 130 has a second welding portion 1315 on one of the first metal surface 1311 and the second metal surface 1312. The first welding portion One of the first welding portion 1313 and the second welding portion 1315 is located on the first metal surface 1311, and the other one of the first welding portion 1313 and the second welding portion 1315 is located on the second metal surface 1312; the second welding portion 1315 is connected to the first welding portion 1313. The projection of the portion 1313 on the second pole piece 130 partially overlaps, and the tab 133 of the second pole piece 130 is welded to the second welding portion 1315 to electrically connect the first metal surface 1311 and the second metal surface 1312 .

Figure 8 is a schematic structural diagram of the tab in the battery core structure provided by the embodiment of the present application. Referring to FIG. 8 , the tab 133 includes a third welding portion 1331 disposed on two opposite surfaces of the tab 133 . and fourth welding portion 1332.

Please continue to refer to FIG. 3 . In the first implementation manner, first align the first welding part 1313 with the third welding part 1331 of the tab 133 , and weld the first welding part 1313 with the third welding part 1331 of the tab 133 . Welding part 1331. Please continue to refer to FIG. 6 . After the cell structure 100 is wound, the second welding portion 1315 is aligned with the fourth welding portion 1332 of the tab 133 , and the second welding portion 1315 is welded to the fourth welding portion of the tab 133 . Department 1332. Thereby, the first metal surface 1311 and the second metal surface 1312 are electrically connected through the tab 133 .

Please continue to refer to FIG. 4 . In the second implementation manner, first align the first welding part 1313 with the fourth welding part 1332 of the tab 133 , and weld the first welding part 1313 with the fourth welding part 1332 of the tab 133 . Welding part 1332. Please continue to refer to FIG. 7 . After the cell structure 100 is wound, the second welding portion 1315 is aligned with the third welding portion 1331 of the tab 133 , and the second welding portion 1315 is welded to the third welding portion of the tab 133 . Department 1331. Thereby, the first metal surface 1311 and the second metal surface 1312 are electrically connected through the tab 133 .

In the first implementation manner and the second implementation manner, the distance between the center of the first welding part 1313 and the center of the second welding part 1315 is greater than or equal to 0 and less than or equal to two-thirds of the pole lug 133 . width.

Specifically, please continue to refer to FIG. 8 . The width of the tab 133 is called the tab width W. The width of the third welding portion 1331 and the width of the fourth welding portion 1332 are both smaller than the tab width W. The width of the third welding portion 1331 The fourth welding portion 1332 is staggered on the two surface portions opposite to the tab 133 . This arrangement can effectively utilize the area of the tab 133 and avoid secondary welding at exactly the same position on the tab 133 . The distance between the center of the third welding part 1331 and the center of the fourth welding part 1332 is called the third spacing L3, and the third spacing L3 is greater than or equal to 0 and less than or equal to two-thirds of the tab width W, whereby , the distance between the centers of the first welding portion 1313 and the second welding portion 1315 respectively opposite to the third welding portion 1331 and the fourth welding portion 1332 is greater than or equal to 0 and less than or equal to two-thirds of the tab width W.

After the battery core structure 100 is wound, the electrical connection between the first metal surface 1311 and the second metal surface 1312 can be achieved by crimping or welding. Below, welding will be used as an example for explanation.

Figure 9 is an enlarged view of point B in Figure 2. Referring to FIG. 9 , in the third implementation manner, the first metal surface 1311 and the second metal surface 1312 of the second pole piece 130 both have second welds. The connecting portion 1315, the projections of the two second welding portions 1315 on the second pole piece 130 overlap, and the two second welding portions 1315 are welded; the second pole piece 130 also includes an insulating glue layer 134, and the insulating glue layer 134 covers the The pole tab 133 on the second pole piece 130 faces the first pole piece 110 .

Please continue to refer to FIG. 5 , the second welding portion 1315 on the first metal surface 1311 is disposed opposite to the tab 133 on the second metal surface 1312 , and the second welding portion 1315 on the second metal surface 1312 is disposed on the composite The blank area 131c at the rear end E of the current collector 131. Please continue to refer to FIG. 9 . After the battery core structure 100 is wound, the second welding portion 1315 on the second metal surface 1312 is opposite to the second welding portion 1315 on the first metal surface 1311 , and then the two second welding portions 1315 on the second metal surface 1312 are opposite to each other. By welding the welding portion 1315, the electrical connection between the first metal surface 1311 and the second metal surface 1312 can be achieved.

Since the tab 133 is electrically connected to the second metal surface 1312, the electrons collected on the first metal surface 1311 and the second metal surface 1312 can be led out through the tab 133.

It should be noted that in the third implementation manner, after the battery core structure 100 is wound, the pole tabs 133 are disposed toward the first pole piece 110. In order to prevent the pole tabs 133 from penetrating the diaphragm 120 and the first pole piece 110, For the active material layer to contact, an insulating glue layer 134 also needs to be provided. The insulating glue layer 134 covers the side of the tab 133 on the second pole piece 130 facing the first pole piece 110 .

Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The technical solutions described in the foregoing embodiments can still be modified, or some or all of the technical features can be equivalently replaced; and these modifications or substitutions do not deviate from the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present application. scope.

Claims

An electric core structure, characterized in that it includes a first pole piece, a separator and a second pole piece that are stacked and wound in sequence, the second pole piece is located on the outside, and the second pole piece includes a composite current collector, an active material layer and tab, the composite current collector has a first metal surface and a second metal surface opposite each other, part of the first metal surface is coated with the active material layer, part of the second metal surface is coated with The active material layer is used to form a double-sided coating area, a single-sided coating area and a blank area on the composite current collector;

One of the first metal surface and the second metal surface has a first welding portion, the tab is welded to the first welding portion, and the tab is connected to the single-sided coating area Or the blank areas are opposite, and the tabs are used to electrically connect the first metal surface and the second metal surface.
The battery core structure according to claim 1, wherein the first welding portion is located on the first metal surface, and the first welding portion is located in the single-sided coating area, and the active material The layer includes a first active material layer located on the first metal surface.
The battery core structure according to claim 2, wherein the distance between the first welding portion and the first active material layer is less than or equal to half the length of the single-sided coating area.
The battery core structure according to claim 1, wherein the first welding portion is located on the second metal surface, and the first welding portion is located in the blank area, and the active material layer includes a third Two active material layers, the second active material layer is located on the second metal surface.
The battery core structure according to claim 4, wherein the distance between the first welding portion and the second active material layer is less than or equal to half the length of the single-sided coating area.
The battery core structure according to claim 4, wherein the second active material layer includes a first active material segment and a second active material segment, the first active material segment, the first welding portion and The second active material segments are arranged on the second metal surface at intervals in sequence.
The battery core structure according to any one of claims 2 to 4, characterized in that one of the first metal surface and the second metal surface of the second pole piece has a second welding portion, and the One of a welding part and the second welding part is located on the first metal surface, and the other of the first welding part and the second welding part is located on the second metal surface;

The second welding part overlaps with the projection of the first welding part on the second pole piece, and the tab of the second pole piece is welded to the second welding part to electrically connect the first metal surface and stated Second metal surface.
The battery core structure according to claim 7, wherein the distance between the center of the first welding part and the center of the second welding part is greater than or equal to 0 and less than or equal to two-thirds of the distance between the center of the first welding part and the center of the second welding part. Describe the width of the pole ear.
The battery core structure according to claim 6, wherein the second pole piece has a second welding portion on both the first metal surface and the second metal surface, and the two second welding portions are on the The projections on the second pole piece overlap, and the two second welding parts are welded.
The battery core structure according to claim 9, further comprising an insulating glue layer covering the side of the tab on the second pole piece facing the first pole piece.
A battery, characterized in that it includes a casing and the battery core structure according to any one of claims 1 to 10, and the battery core structure is arranged in the casing.