WO2023131049A1

WO2023131049A1 - Pole sheet and battery

Info

Publication number: WO2023131049A1
Application number: PCT/CN2022/143432
Authority: WO
Inventors: 付小虎; 邹浒; 李世广
Original assignee: 珠海冠宇电池股份有限公司
Priority date: 2022-01-07
Filing date: 2022-12-29
Publication date: 2023-07-13
Also published as: CN216648356U

Abstract

The present application provides a pole sheet and a battery. The pole sheet comprises a current collector; the current collector comprises a coating area and a tab located on one side of the coating area; an active coating is provided on the coating area; the tab comprises a first area and a second area; the second area is located between the coating area and the first area; a step structure is formed, on at least one side surface of two opposite sides in the length direction of the pole sheet, in the second area. By forming the step structure in the second area, the width of the tab can be effectively increased, such that the overall structural strength of the tab is enhanced, and the situation that the tab is easily pulled apart under the action of external force is avoided.

Description

Electrode and battery

technical field

The present application relates to the technical field of batteries, in particular to a pole piece and a battery.

Background technique

A battery is a component that converts chemical energy into electrical energy and has a wide range of applications in daily life and work. For example, lithium-ion batteries are often used in various electronic devices such as mobile phones, cameras, electronic watches, Bluetooth headsets, electric toys, etc., to provide power for electronic devices. It occupies an increasingly important position in people's life and work.

The lithium-ion battery includes an electric core, and the electric core includes a positive pole piece and a negative pole piece, and a separator is arranged between the positive pole piece and the negative pole piece. Both the positive electrode sheet and the negative electrode sheet include a current collector and a coating coated on the current collector, wherein the current collector of the positive electrode sheet is coated with a positive active coating, and the current collector of the negative electrode sheet is coated with Negative active coating. Positive tabs are formed on the current collector of the positive pole piece, and negative pole tabs are formed on the current collector of the negative pole piece. Usually, in the manufacture of the pole piece, the empty foil area and the coating area are first divided on the current collector. , coating the active coating on the coating area, and then forming the main part of the pole piece in the coating area by die-cutting, and forming tabs in the empty foil area or the edge of the empty foil area and the coating area.

However, the above-mentioned lug structure is weak, and it is easy to break under the pull of an external force, which reduces the performance of the battery.

Contents of the invention

The present application provides a pole piece and a battery to solve the problem that in the pole piece of the existing battery, the structural strength of the tab is weak, and it is easy to break when pulled by an external force, thereby reducing the performance of the battery.

The first aspect of the present application provides a pole piece, including: a current collector, the current collector includes a coating area and a tab, and the tab is located at the side of the coating area in the width direction of the pole piece On one side, an active coating is provided on the coating area;

The tab includes a first area and a second area, the second area is located between the coating area and the first area, and the second area is on opposite sides along the length direction of the pole piece A stepped structure is formed on at least one side.

By forming a stepped structure in the second area, compared with the tabs of the prior art, the width of the tab can be effectively increased under the premise of ensuring that the edge of the tab does not pierce the diaphragm and cause a short circuit, thereby enhancing the overall stability of the tab. Structural strength prevents the tab from being easily torn off under external force, thereby improving the reliability of the battery loaded with the pole piece. At the same time, the lug structure matches the existing manufacturing process and is easy to process, thereby reducing the requirements for cutting equipment.

In a possible implementation manner, the tabs have burr structures on opposite sides along the length direction of the pole piece, and the length of the burr structures is less than 5 μm.

In a possible implementation manner, the second region is covered with the active coating.

In a possible implementation manner, the pole piece further includes an insulating layer, and the insulating layer includes a first insulating layer covering the second region.

In a possible implementation manner, the current collector includes an insulating coating area located between the coating area and the tab;

The insulating layer also includes a second insulating layer overlying the insulating coating region;

The second insulating layer extends along the length direction of the pole piece.

In a possible implementation manner, the width of the insulating coating area in the width direction of the pole piece ranges from 0.1 mm to 5 mm

In a possible implementation manner, the width of the second region in the width direction of the pole piece is greater than the width of the insulating coating region.

In a possible implementation manner, the second region includes a first subregion and a second subregion, the first subregion is located between the second subregion and the first region, and the On one side of the tab along the length direction of the pole piece, the first side of the first subregion and the second side of the second subregion jointly form the stepped structure.

In a possible implementation manner, the included angle of the stepped structure is 120°-180°.

In a possible implementation manner, the distance from the intersection of the second side and the first side to the coating area is greater than 0 mm and less than 10 mm;

And/or, in the width direction of the pole piece, the distance from the intersection of the first side and the second side to the first region is 0.1mm-5mm.

In a possible implementation manner, in the length direction of the pole piece, the distance from the intersection of the first side and the second side to the first area is greater than 0 mm and smaller than the first area half of the length.

In a possible implementation manner, cross-sectional shapes of the first side and the second side are arc or inclined.

In a possible implementation manner, the stepped structure is formed on opposite sides of the second region;

On the other side of the tab along the length direction of the pole piece, the third side of the first subregion and the fourth side of the second subregion jointly form the stepped structure;

The difference between the distance from the intersection of the first side and the second side to the coating area and the distance from the intersection of the third side and the fourth side to the coating area is less than the specified one-third of the length of the first region;

And/or, in the length direction of the pole piece, the distance from the intersection of the first side and the second side to the first region is the same as the distance from the intersection of the third side and the fourth side to The difference between the distances of the first regions is less than one third of the length of the first regions.

In a possible implementation manner, the tab is formed by punching twice, the first side is a cut surface formed on the second region during the second punching, and the second side is a During punching, the cut surface formed on the second region.

The second aspect of the present application provides a battery, including a cell, the cell includes a positive pole piece, a negative pole piece, and a separator, and the separator is arranged between the positive pole piece and the negative pole piece;

At least one of the positive pole piece and the negative pole piece is any pole piece described above.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application or 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 accompanying drawings in the following description These are some embodiments of the present application. Those skilled in the art can also obtain other drawings based on these drawings without any creative effort.

Fig. 1 is the structural representation of existing a kind of pole piece;

Figure 2 is an enlarged view of the local structure of Figure 1;

FIG. 3 is a schematic structural diagram of a pole piece provided in an embodiment of the present application;

Figure 4 is an enlarged view of the local structure of Figure 3;

Fig. 5 is a schematic diagram of secondary punching of a pole piece provided in the embodiment of the present application;

Fig. 6 is an enlarged view of the partial structure of another pole piece provided by the embodiment of the present application;

Fig. 7 is an enlarged view of the local structure of another pole piece provided by the embodiment of the present application;

Fig. 8 is a schematic diagram of the size of another pole piece provided by the embodiment of the present application;

Fig. 9 is an enlarged view of the partial structure of another pole piece provided in the embodiment of the present application;

Fig. 10 is a schematic diagram of a pole piece punching process provided by the embodiment of the present application;

Fig. 11 is a schematic diagram of a pole piece punching track provided by the embodiment of the present application;

Fig. 12 is a schematic diagram of another pole piece punching track provided by the embodiment of the present application;

FIG. 13 is a schematic structural diagram of a battery cell provided in an embodiment of the present application.

Explanation of reference signs:

100-electrode; 10-coating area; 20-active coating; 30-ear; 31-first area; 32-second area; 321-step structure; 322-first sub-area; 3221-first 3222-the third side; 323-the second sub-region; 3231-the second side; 3232-the fourth side; 40-insulation layer; 41-the first insulation layer; 42-the second insulation layer; 50-insulation coating layout area.

Detailed ways

In order to make the purposes, 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 It is a part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of this application.

FIG. 1 is a schematic structural diagram of a conventional pole piece, and FIG. 2 is an enlarged view of a partial structure of FIG. 1 .

As mentioned in the above background, when manufacturing pole pieces, firstly, the empty foil area and the coating area will be divided on the current collector, and the active coating layer will be coated on the coating layer. The main part of the pole piece is formed on the layer, and the tab is formed on the empty foil area, or the tab is formed at the edge of the empty foil area and the coating area, that is, the tab can be formed entirely by the empty foil area, and the tab is Empty foil, or, as shown in Figure 1, some tabs can also have an active coating 2, and some tabs are formed by the empty foil area 1a, that is, some tabs are empty foils, and some tabs have an active coating 2.

Usually, the tabs are used to electrically connect with the battery case to draw out the current. However, the structure of the above-mentioned tabs is relatively weak. During the transportation or use of the battery, it is inevitable that collisions or bumps will occur, and the tabs will be pulled by external forces, which will easily break the tabs, thereby affecting the battery cell and the battery case. The conductivity between them reduces the stability of battery performance.

Based on this, the embodiment of the present application provides a pole piece and a battery. The pole piece forms a stepped structure on both sides of the pole piece, thereby effectively improving the structural strength of the pole piece, reducing or avoiding the occurrence of the pole piece under the action of external force. Fracture, improve the stability of the battery.

Fig. 3 is a schematic structural diagram of a pole piece provided by the embodiment of the present application, Fig. 4 is an enlarged view of the partial structure of Fig. 3, and Fig. 5 is a schematic diagram of secondary punching of a pole piece provided by the embodiment of the present application.

Referring to Fig. 3, a pole piece 100 provided by the embodiment of the present application includes a current collector (not shown in the figure), the current collector includes a coating area 10, and an active coating 20 is arranged on the coating area 10 . Specifically, the pole piece 100 can be a positive pole piece 100, and the coating area 10 is provided with a positive active coating 20, and the material of the positive active coating 20 can be lithium cobaltate, lithium iron phosphate, lithium manganate, Lithium nickel manganese oxide, etc. Of course, in some examples, the positive electrode active material can also be other high potential materials.

The pole piece 100 can also be a negative pole piece 100, and what is set on the coating area 10 is a negative active coating, and the material of this negative active coating can be materials such as graphite, silicon, carbon, certainly, in some examples, negative pole The active material can also be other low potential materials.

Wherein, the current collector also includes a tab 30, the current collector extends outwards to form the tab 30, and the tab 30 can also be formed by punching and other processes, the tab 30 is located in the coating area 10 in the width direction of the pole piece 100 (as shown in the figure On one side of the Y direction), the number of tabs 30 can be one, or the number of tabs 30 formed can be multiple, and a plurality of tabs 30 can be along the length direction of the pole piece 100 (as shown in the figure x direction) distribution.

In the embodiment of the present application, the width direction of the pole piece 100 can be the y direction in the figure, the width direction of the pole piece 100 is consistent with the direction from the coating area 10 to the tab 30, and the length direction of the pole piece 100 is consistent with the direction of the pole piece 100. The width direction is vertical, such as the x direction in the figure. Correspondingly, in the embodiment of the present application, the width refers to the dimension in the width direction of the pole piece 100 , and the length refers to the dimension in the length direction of the pole piece 100 .

When the current collector forms the tab 30, part of the active coating 20 can be extended to cover the tab 30, that is, as shown in FIG. The tab 30 is an empty foil. Alternatively, there may be no active coating on the tab 30 , that is, the tab 30 is an empty foil.

As shown in FIG. 4 , the tab 30 may include a first area 31 and a second area 32, the second area 32 is located between the coating area 10 and the first area 31, wherein the first area 31 is used to achieve electrical contact with the outside. Connection, for example, for making electrical connection with the case of the battery. Specifically, the electrical connection between the first region 31 and the outside can be realized by means of ultrasonic welding, laser welding and the like. For example, if a part of the lug 30 is covered with the active coating 20 as an example, the first area 31 may be an empty foil to facilitate electrical connection with the outside, and the second area 32 may be the part covered with the active coating 20 .

Along the length direction of the pole piece 100 , at least one of the two opposite sides of the second region 32 is formed with a stepped structure 321 . For example, step structures 321 may be formed on opposite sides of the second region 32 as an example. Compared with the tabs of the prior art, under the premise of ensuring that the edges of the tabs 30 will not pierce the diaphragm and cause a short circuit, The width of the tab 30 can be effectively increased (the width direction of the tab is consistent with the length direction of the current collector), thereby enhancing the overall structural strength of the tab 30 and preventing the tab 30 from being easily torn off under the action of an external force. Therefore, the reliability of the battery loaded with the pole piece 100 is improved. At the same time, the structure of the tab 30 matches the existing manufacturing process and is easy to process, thereby reducing the requirement for cutting equipment.

Wherein, as shown in FIG. 5 , the stepped structure 321 can firstly form the main part of the tab 30 through one punching (see FIG. 10 ), and then through secondary punching (see FIG. 10 ), The punching track can extend from the second area 32 to the first area 31, remove the opposite side edges of the tab in the first area 31, and form a stepped structure on the opposite sides of the second area 32 of the tab 30 321.

It should be noted that, in the embodiment of the present application, the step structure 321 may be formed only on one of the two opposite sides in the second region 32 , or it may also be formed on the two opposite sides in the second region 32 Both are provided with a stepped structure 321 . The following description will be described by taking the step structure 321 disposed on two opposite side surfaces of the second region 32 as an example.

Wherein, the formed tab 30 also has a burr structure on opposite sides in the length direction of the pole piece 100 , wherein the length range of the burr structure may be less than 5 μm. The length of the burr structure on the tab 30 can be well controlled to make the length smaller, thereby further effectively reducing or avoiding the probability of the burr structure piercing the diaphragm when the battery cell is formed, and improving the safety performance of the battery.

Wherein, referring to FIG. 4 , the active coating 20 may extend to cover the second region 32 , that is, the second region 32 is covered with the active coating 20 . Specifically, for example, during one punching, the edges of the empty foil area and the coating area 10 are both used to form the tab 30 , so that the second area 32 of the tab 30 is covered with the active coating 20 .

It should be noted that the active coating 20 can completely cover the second region 32 . In this way, the burrs formed in the primary punching process can be concentrated on the side of the first region 31 adjacent to the second region 32, thereby ensuring that the generated burrs can be effectively removed when the second punching forms the stepped structure 321, further The number and length of the burrs on the tab 30 are reduced, and the safety performance of the battery cell is improved.

Fig. 6 is an enlarged view of a partial structure of another pole piece provided in the embodiment of the present application.

In the embodiment of the present application, in a possible example, as shown in FIG. 6, the pole piece 100 may further include an insulating layer 40, wherein the insulating layer 40 may be disposed on the tab 30, specifically, the insulating layer 40 includes a first insulating layer 41 covering the second region 32 .

Wherein, the setting of the insulating layer 40 helps to increase the edge tension of the pole piece 100 , so that when the battery cell is formed, it helps to improve the strength of the battery cell and ensure the performance of the battery cell. At the same time, the insulating layer 40 can also reduce or avoid the contact connection between the tabs 30 on the adjacent two pole pieces 100 or any adjacent two tabs 30 when forming the battery core, further improving the safety performance of the battery core.

Correspondingly, as shown in FIG. 6 , the insulating layer 40 can completely cover the second region 32 , which can further increase the edge tension of the pole piece 100 , improve the strength of the battery cell, and ensure the performance of the battery cell. At the same time, it can further reduce or avoid the contact connection between the tabs 30 on the adjacent two pole pieces 100 or between any adjacent two tabs 30 , so as to improve the safety performance of the battery cell.

Continuing to refer to FIG. 6, the current collector may include a coating area 10 and an insulating coating area 50. The insulating coating area 50 is located between the coating area 10 and the tab 30, and may be between the insulating coating area 50 and the tab. 30 are provided with an insulating layer 40 . Specifically, the insulating layer 40 may include a first insulating layer 41 and a second insulating layer 42, the first insulating layer 41 is disposed on the second region 32 of the tab 30, and the second insulating layer 42 may be disposed on the insulating coating. On the layout area 50 , the second insulating layer 42 is in contact with the active coating layer 20 . When forming the battery core, the second insulating layer 42 on the current collector can also play the role of isolating the positive pole piece 100 and the negative pole piece 100, and can further ensure the insulation performance between the positive pole piece 100 and the negative pole piece 100, Improve the safety performance of battery cells.

Specifically, the width range of the insulating coating area 50 in the width direction of the pole piece is 0.1 mm-5 mm, that is, the width range of the second insulating layer 42 covering the insulating coating area 50 can be 0.1 mm-5 mm, Make the second insulating layer 42 have a smaller extension width, which helps to increase the width of the active coating 20 on the current collector, while ensuring the insulation performance between the pole pieces 100, it can also improve the energy density of the pole piece 100, and then Improve the energy density of the battery and enhance the electrical performance of the battery.

Wherein, the width of the second region 32 in the pole piece width direction can be greater than the width of the insulating coating region 50, that is, the covering setting width of the first insulating layer is greater than the covering setting width of the second insulating layer 42, in other words, more The insulating layer 40 is distributed on the second region 32 of the tab 30, and while effectively increasing the area of the active coating 20 to increase the energy density of the pole piece 100, it can effectively improve the insulation between the tabs 30 when forming a cell. Sex, reduce or avoid the electrical contact between the tabs 30, and further improve the safety performance of the battery cell.

FIG. 7 is an enlarged view of a partial structure of another pole piece provided by the embodiment of the present application, and FIG. 8 is a schematic diagram of the size of another pole piece provided by the embodiment of the present application.

In the embodiment of the present application, as shown in FIG. 7 , the second region 32 may include a first subregion 322 and a second subregion 323 , and the first subregion 322 is located between the second subregion 323 and the first region 31 , wherein, one side of the first sub-region 322 has a first side 3221, the first side 3221 may be a cut surface formed on the second region 32 of the tab 30 during secondary punching, and the second sub-region 323 One side has a second side 3231 , and the second side 3231 may be a cut surface formed on the second region 32 of the tab 30 during one punching.

That is, by punching twice, while forming the tab 30, the burrs on both sides of the first area 31 of the tab 30 are removed, and the first side 3221 and the second side are respectively formed on the second area 32 of the tab 30. The two side surfaces 3231, the first side 3221 and the second side 3231 together form a stepped structure 321 to achieve the effect of removing burrs.

Continue referring to FIG. 7 , wherein an angle is formed between the first side 3221 and the second side 3231, and the value range of the angle can be 120°-180°, so that the second area 32 can be effectively reduced or avoided. The sharp corner structure on the top prevents the sharp corner structure from piercing the diaphragm, thereby effectively avoiding safety accidents such as short circuit of the battery due to rupture of the diaphragm, and effectively improving the safety of the battery.

It should be noted that when the cross-sections of the first side 3221 and the second side 3231 are arc surfaces, the angle between the first side 3221 and the second side 3231 is between the tangents at the intersections of the first side 3221 and the second side 3231 angle.

In the embodiment of the present application, as shown in FIG. 8 , the range of the distance L1 from the intersection point between the first side 3221 and the second side 3231 to the coating area 10 can be greater than 0 mm and less than 10 mm. And/or, in the length direction of the pole piece 100 (that is, the x direction in the figure), the distance L2 from the intersection of the first side 3221 and the second side 3231 to the first region 31 of the tab 30 is 0.1 mm-5 mm.

This can effectively control the secondary punching, the distance between the punching track and the coating area 10, reduce or avoid the secondary punching track from the coating area 10 too close to the active coating 20 on the coating area 10 Damage occurs, effectively increasing the total amount of active coating 20 in pole piece 100 . At the same time, this distance range can also effectively ensure the removal effect of the secondary punching on the burr on the tab 30, further improving the safety of the battery.

Continuing to refer to FIG. 8 , in the length direction of the pole piece 100 (that is, the x direction in the figure), the distance L2 from the intersection point between the first side 3221 and the second side 3231 to the first region 31 of the tab 30 is greater than 0 mm , and less than half of the length L of the first region 31, which can effectively improve the effect of removing burrs on the tab 30. At the same time, it can also effectively guarantee the length of the tab 30 , effectively reduce or avoid reducing the structural strength of the tab 30 due to excessive secondary punching, and effectively ensure the structural stability of the tab 30 .

Fig. 9 is an enlarged view of a partial structure of another pole piece provided in the embodiment of the present application.

As shown in FIG. 8 , the cross-sectional shape of the first side 3221 and the second side 3231 can be arc-shaped, or, as shown in FIG. 9 , the cross-sectional shape of the first side 3221 and the second side 3231 can also be inclined. Specifically, the shapes of the first side 3221 and the second side 3231 can be selected and set according to the structural design of the battery and specific scene requirements.

As shown in FIG. 7 and FIG. 8 , in the embodiment of the present application, step structures 321 may be formed on both sides opposite to the second region 32 , specifically, the first subregion 322 also includes a first side 3221 Opposite to the third side 3222 , the second sub-region 323 further includes a fourth side 3232 opposite to the second side 3231 . Wherein, the first side 3221 of the first sub-region 322 and the second side 3231 of the second sub-region 323 jointly form the first stepped structure 321, the third side 3222 of the first sub-region 322 and the second side of the second sub-region 323 The four sides 3232 jointly form the second stepped structure 321 . That is to say, secondary punching can be performed on both sides of the tab 30 to remove the burrs on both sides of the tab 30 , so as to further improve the effect of removing the burrs and improve the safety of the battery.

The distance from the intersection of the first side 3221 and the second side 3231 to the coating area 10 is L1, and the distance from the intersection of the third side 3222 and the fourth side 3232 to the coating area 10 is L4, wherein the distance L1 and the distance L4 The difference between them can be less than one-third of the length L of the first region 31, that is, when the two sides of the tab 30 are respectively punched twice, the punching on both sides in the length direction of the pole piece 100 There will be a certain gap in the cutting amount, and the range of the gap can be less than one-third of the length L of the first region 31 of the tab 30, which can effectively reduce the punching gap on both sides of the tab 30 and improve the stability of the structures on both sides of the tab 30. Symmetry, thereby effectively improving the manufacturing accuracy of the tab 30 and improving the structural strength of the tab 30 .

And/or, in the length direction of the tab 30, the distance from the intersection of the first side 3221 and the second side 3231 to the first area 31 is L2, and the intersection of the third side 3222 and the fourth side 3232 to the first area The distance 31 is L3, wherein the difference between the distance L2 and the distance L3 is less than one third of the length L of the first region 31 of the tab 30 . That is. That is, when performing secondary punching on both sides of the tab 30, there will also be a certain gap in the punching amount of the punching on both sides in the width direction of the pole piece 100, and the range of the gap can be smaller than that of the first area of the tab 30. 31 length L, which can further reduce the punching gap on both sides of the tab 30, thereby further improving the symmetry of the structures on both sides of the tab 30, improving the manufacturing accuracy of the tab 30, and improving the structure of the tab 30 strength.

Figure 10 is a schematic diagram of a pole piece punching process provided by the embodiment of the present application, Figure 11 is a schematic diagram of a pole piece punching track provided by the embodiment of the present application, and Figure 12 is another pole piece provided by the embodiment of the present application Schematic diagram of punching trajectory.

In the embodiment of the present application, as shown in FIG. 10, when manufacturing the pole piece 100, the active coating 20 can be first formed on the coating area 10a of the current collector, and then the coated current collector is rolled and divided. Cut to form a current collector of multiple small strips.

As shown in FIG. 11 , the divided current collector is then punched once to form the coating area 10 of the current collector in the coating area 10a, and form a tab 30 on the empty foil area 10b. The tab 30 can have The first area 31 and the second area 32 are two areas. Then perform secondary punching, the track of the secondary punching extends from the second area 32 to the first area 31, cuts off the edges on opposite sides of the first area 31, and forms a stepped structure 321 on the opposite sides of the second area 32, Thus, the above pole piece 100 is obtained.

It should be understood that, when manufacturing the pole piece 100 , the above-mentioned secondary punching may also be performed first, and then a primary punching is performed. That is to say, the area for forming the tab 30 can be divided on the current collector, and the area is divided into a first area 31 and a second area 32, and then the corresponding area of the tab 30 is punched so that the punching track starts from the first area 31 and the second area 32. The second area 32 extends to the first area 31 . Then the current collector is punched as a whole, so that the current collector forms a coating area 10 in the coating area, and a tab 30 is formed on the empty foil area, and the two punching tracks intersect so that both sides of the edge of the first area 31 can removed, and a stepped structure 321 is formed on the second region 32 .

By forming a stepped structure on the second area of the tab, the burrs on the edges on both sides of the tab can be removed. For example, if the tab can be formed by punching once, more burrs will be formed on the edges of the opposite sides of the tab. And the long burr structure, wherein most of the burr structures are located on the side of the first region adjacent to the second region. Secondary punching can then be carried out, the track of punching can extend from the second area to the first area, the opposite side edges of the first area are removed, and steps are formed on the opposite sides of the second area of the tab structure, so as to achieve the purpose of removing the burrs on the tabs, realize the control of the burrs on the tabs on the basis of introducing as few new burrs as possible, reduce the length of the burrs on the tabs, and further reduce or avoid the tabs The formation of multiple burrs and longer burrs can improve the safety performance of battery cells. Moreover, it can also reduce the requirement for burr precision in one-time punching, reduce the precision and complexity of the mold, help reduce the cost of the mold, and at the same time increase the service life of the mold. The production cost of the pole piece is greatly reduced.

Wherein, it should be noted that in the embodiment of the present application, the above-mentioned pole piece 100 can be formed by punching, or can also be cut or cut twice by cutting with a knife or laser cutting to form the above-mentioned pole piece 100. Pole piece 100.

Punching to remove the burrs on both sides of the first area 31 of the tab 30, and when the second area 32 forms a stepped structure 321, the punching track 200 extends from the second area 32 to the first area 31, and the punching track 200 The shape can be various. For example, as shown in FIG. 11 , the punching track 200 may consist of two U-shaped tracks, the two U-shaped tracks are set opposite to each other, and the two U-shaped tracks are respectively located on both sides of the tab 30 .

Alternatively, as shown in FIG. 12 , the punching track 200 may be a zigzag track. Of course, in some examples, the punching track 200 can also be other types of tracks, which can remove the burrs on both sides of the first region 31 and form the stepped structure 321 on the second region 32 after two times of punching.

The embodiment of the present application also provides a battery, wherein the battery can be a lithium-ion battery, a button battery, etc., and the battery can be used in electronic equipment such as mobile phones, cameras, Bluetooth headsets, electronic watches, and electric toys to provide power supply.

The battery at least includes an electric core. As shown in FIG. 13 , the electric core includes a positive pole piece 101 , a negative pole piece 102 and a separator 103 , and the separator 103 is arranged between the positive pole piece 101 and the negative pole piece 102 . Wherein, at least one of the positive pole piece 101 and the negative pole piece 102 is the above-mentioned pole piece, that is, only the negative pole piece can adopt the above-mentioned pole piece structure, or it can also be that only the positive pole piece adopts the above-mentioned pole piece structure , or, it is also possible that both the positive pole piece and the negative pole piece adopt the above-mentioned pole piece structure.

Wherein, depending on the structure of the battery design, the structure of the cell can be laminated or wound. When the structure of the cell is wound, the positive pole piece and the negative pole piece can be arranged in a winding manner.

Alternatively, as shown in FIG. 13 , when the structure of the cell is laminated, the positive pole piece 101 and the negative pole piece 102 can be arranged in a laminated manner.

Wherein, the current collector of the positive electrode sheet 101 may have the above-mentioned coating area and insulating coating area, and the second insulating layer 42 is disposed on the insulating coating area.

It should be noted here that the numerical values and numerical ranges involved in the embodiments of the present application are approximate values, and there may be a certain range of errors due to the influence of the manufacturing process, and those skilled in the art may consider these errors to be negligible.

In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", " The orientation or positional relationship indicated by "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner" and "outer" are based on the orientation or position shown in the drawings The positional relationship is only for the convenience of describing the present application and simplifying the description, but does not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present application.

In the description of the present application, it should be understood that the terms "comprising" and "having" and any of their variations used herein are intended to cover a non-exclusive inclusion, for example, a process comprising a series of steps or units, A method, system, product or device is not necessarily limited to those steps or elements explicitly listed, but may include other steps or elements not explicitly listed or inherent to the process, method, product or device.

Unless otherwise clearly stipulated and limited, the terms "installation", "connection", "connection" and "fixation" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral body; it can be It can be directly connected or indirectly connected through an intermediary, and can be an internal connection between two elements or an interaction relationship between two elements. Those of ordinary skill in the art can understand the specific meanings of the above terms in this application according to specific situations. In addition, the terms "first", "second", etc. are used for descriptive purposes only, and should not be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, rather than limiting them; although the application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the various embodiments of the present application. scope.

Claims

A pole piece, characterized in that it includes: a current collector, the current collector includes a coating area and a tab, the tab is located on one side of the coating area in the width direction of the pole piece, An active coating is provided on the coating area;

The tab includes a first area and a second area, the second area is located between the coating area and the first area, and the second area is along opposite sides of the length direction of the pole piece A step structure is formed on at least one side surface.
The pole piece according to claim 1, wherein the tabs have burr structures on opposite sides along the length direction of the pole piece, and the length of the burr structures is less than 5 μm.
The pole piece according to claim 1 or 2, characterized in that the second region is covered with the active coating.
The pole piece according to any one of claims 1-3, wherein the pole piece further comprises an insulating layer, and the insulating layer comprises a first insulating layer covering the second region.
The pole piece according to claim 4, wherein the current collector comprises an insulating coating area located between the coating area and the tab;

The insulating layer also includes a second insulating layer overlying the insulating coating region;

The second insulating layer extends along the length direction of the pole piece.
The pole piece according to claim 5, characterized in that, the width of the insulating coating area in the width direction of the pole piece ranges from 0.1 mm to 5 mm.
The pole piece according to claim 5, characterized in that, the width of the second region in the width direction of the pole piece is larger than the width of the insulating coating area.
The pole piece according to any one of claims 1-7, wherein the second region comprises a first subregion and a second subregion, and the first subregion is located between the second subregion and the second subregion. between said first regions;

On one side of the tab along the length direction of the pole piece, the first side surface of the first subregion and the second side surface of the second subregion jointly form the stepped structure.
The pole piece according to claim 8, wherein the angle formed between the first side surface of the first subregion and the second side surface of the second subregion is 120°-180°.
The pole piece according to claim 8, characterized in that the distance from the intersection of the second side and the first side to the coating area is greater than 0 mm and less than 10 mm;

And/or, in the width direction of the pole piece, the distance from the intersection of the first side and the second side to the first region is 0.1mm-5mm.
The pole piece according to claim 8, characterized in that, in the length direction of the pole piece, the distance from the intersection of the first side and the second side to the first region is greater than 0 mm and less than half of the length of the first region.
The pole piece according to claim 8, wherein the cross-sectional shapes of the first side and the second side are arc or inclined.
The pole piece according to claim 8, wherein the stepped structure is formed on opposite sides of the second region;

On the other side of the tab along the length direction of the pole piece, the third side of the first subregion and the fourth side of the second subregion jointly form the stepped structure;

The difference between the distance from the intersection of the first side and the second side to the coating area and the distance from the intersection of the third side and the fourth side to the coating area is less than the specified one-third of the length of the first region;

And/or, in the length direction of the pole piece, the distance from the intersection of the first side and the second side to the first region is the same as the distance from the intersection of the third side and the fourth side to The difference between the distances of the first regions is less than one third of the length of the first regions.
The pole piece according to claim 8, wherein the tab is formed by punching twice, the first side is a cut surface formed on the second region during the second punching, and the The second side is a cut surface formed on the second region during one punching.
A battery, characterized in that it includes an electric core, the electric core includes a positive pole piece, a negative pole piece and a diaphragm, and the diaphragm is arranged between the positive pole piece and the negative pole piece;

At least one of the positive pole piece and the negative pole piece is the pole piece according to any one of claims 1-14.