CN113707842A

CN113707842A - Electrode pole piece, manufacturing method thereof and battery cell

Info

Publication number: CN113707842A
Application number: CN202111005979.8A
Authority: CN
Inventors: 张君; 李小芳
Original assignee: Vivo Mobile Communication Co Ltd
Current assignee: Vivo Mobile Communication Co Ltd
Priority date: 2021-08-30
Filing date: 2021-08-30
Publication date: 2021-11-26

Abstract

The application discloses an electrode plate, a manufacturing method thereof and a battery cell. The electrode plate comprises a current collector, a first material layer and a second material layer, wherein the first material layer and the second material layer are arranged on the same side of the current collector; the second material layer is arranged on at least one side of the first material layer in the width direction of the current collector; wherein the kinetic properties of the second material are higher than the kinetic properties of the first material; the first material is the material of the first material layer, and the second material is the material of the second material layer. The second material layer with higher dynamic performance is arranged on at least one side of the first material layer, so that the lithium precipitation phenomenon at the edge position of the first material layer is avoided, and the service life of the electrode plate is prolonged.

Description

Electrode pole piece, manufacturing method thereof and battery cell

Technical Field

The application belongs to the technical field of batteries, and particularly relates to an electrode plate, a manufacturing method thereof and a battery core.

Background

With the development of battery technology, users have higher and higher requirements on the performance of batteries. For example, for a lithium battery which is currently used, a user may need to have a higher charging efficiency and a higher electric energy capacity.

In the related art, in order to make a lithium battery have a higher electric energy capacity, a material with a higher energy density is generally coated on an electrode plate. However, in practical applications, the electrode plate is prone to lithium precipitation due to low dynamic performance of the coating material, which results in a short service life of the electrode plate.

Disclosure of Invention

The application aims to provide an electrode plate, a manufacturing method thereof and a battery cell, and at least solves the problem that the service life of the electrode plate is short due to the fact that the electrode plate is easy to have a lithium precipitation phenomenon in the related technology.

In order to solve the technical problem, the present application is implemented as follows:

in a first aspect, an embodiment of the present application provides an electrode pad, including: the current collector, the first material layer and the second material layer are arranged on the same side of the current collector; the second material layer is arranged on at least one side of the first material layer in the width direction of the current collector;

wherein the kinetic properties of the second material are higher than the kinetic properties of the first material; the first material is the material of the first material layer, and the second material is the material of the second material layer.

In a second aspect, an embodiment of the present application provides a method for manufacturing an electrode sheet, including:

providing a current collector, wherein one side surface of the current collector comprises a first area and a second area, and the second area is positioned on at least one side of the first area in the width direction of the current collector;

spraying a first material on the first area, and spraying a second material on the second area to obtain an electrode pole piece;

wherein the kinetic properties of the second material are higher than the kinetic properties of the first material.

In a third aspect, an embodiment of the present application provides an electrical core, including a positive electrode plate, a negative electrode plate, and a diaphragm, where the positive electrode plate and the negative electrode plate are respectively connected to two sides of the diaphragm in a thickness direction;

the negative electrode plate is the electrode plate as shown in the first aspect.

The electrode plate provided by the embodiment of the application comprises a current collector, and a first material layer and a second material layer which are arranged on the same side of the current collector, wherein in the width direction of the current collector, the second material layer is arranged on at least one side of the first material layer, and the dynamic performance of a second material of the second material layer is higher than that of a first material of the first material layer; therefore, the second material layer with higher dynamic performance is arranged on at least one side of the first material layer, so that the phenomenon of lithium precipitation at the edge position of the first material layer is avoided, and the service life of the electrode plate is prolonged.

Additional aspects and advantages of the present application will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the present application.

Drawings

The above and/or additional aspects and advantages of the present application will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a schematic diagram illustrating a lithium deposition position of an electrode plate in the related art;

FIG. 2 is a schematic structural diagram of an electrode pad according to an embodiment of the present disclosure;

FIG. 3 is a second schematic diagram of the electrode sheet according to one embodiment of the present application;

FIG. 4 is an exemplary diagram of a cross-section of the electrode pad shown in FIG. 2;

FIG. 5 is a third schematic view of a structure of an electrode pad according to an embodiment of the present application;

fig. 6 is a schematic structural view of a current collector provided with a fourth material layer in a single-sided area;

fig. 7 is one of example views of a location area of a fourth material layer on a current collector;

fig. 8 is a second example illustration of the location area of the fourth material layer on the current collector;

fig. 9 is a schematic flow chart illustrating a method for manufacturing an electrode pad according to another embodiment of the present disclosure;

FIG. 10 is a schematic diagram of the fabrication of the electrode pad of FIG. 2 using a fabrication apparatus;

fig. 11 is a schematic structural diagram of a cell according to another embodiment of the present application;

fig. 12 is a second schematic structural diagram of a battery cell according to another embodiment of the present application;

fig. 13 is a third schematic structural diagram of a cell according to another embodiment of the present application;

fig. 14 is a schematic structural diagram of a negative electrode tab in a battery cell according to yet another embodiment of the present application;

wherein fig. 2 to 8 show: 110-current collector, 121-first material layer, 122-second material layer, 1221-first sub material layer, 1222-second sub material layer, 123-third material layer, 124-fourth material layer;

shown in fig. 10: 200-current collector, 210-first region, 221-first sub-region, 222-second sub-region;

shown in fig. 11 to 14: 310-positive pole piece, 311-first end, 312-second end, 320-negative pole piece, 321-first current collector, 322-first material layer, 323-second material layer, 324-third material layer, 325-fifth material layer, 326-sixth material layer, 330-diaphragm, 340-negative pole tab and 350-positive pole rubberizing.

Detailed Description

Reference will now be made in detail to the embodiments of the present application, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary only for the purpose of explaining the present application and are not to be construed as limiting the present application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The features of the terms first and second in the description and in the claims of the present application may explicitly or implicitly include one or more of such features. In the description of the present application, "a plurality" means two or more unless otherwise specified. In addition, "and/or" in the specification and claims means at least one of connected objects, a character "/" generally means that a preceding and succeeding related objects are in an "or" relationship.

In the description of the present application, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the present application and to simplify the description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the present application.

In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art.

Generally, the performance of a battery is manifested in both the electrical energy capacity and the charging efficiency. For the batteries of lithium batteries and other types, the selection of the coating material of the electrode pole piece in the battery core has a great influence on the performance of the battery.

For example, the application of the coating material with high energy density can improve the electric energy capacity of the battery; the application of the coating material with high dynamic performance is helpful to improve the charging efficiency of the battery.

It will be readily understood that the dynamic properties of a material may generally be expressed in terms of electrical conductivity, or anisotropy, among other criteria. For example, a material with better conductivity may be considered to have higher dynamic properties to some extent.

Generally, when the energy density of the coating material used for the electrode pad is high, the kinetic performance of the coating material is poor.

Taking the electrode plate as the negative electrode plate as an example, when the negative electrode plate is made of a coating material with high energy density, the lithium deposition phenomenon may be caused due to the poor dynamic performance of the coating material, which leads to the reduction of the service life of the battery cell, and in the case of serious lithium deposition, the safety problem may be brought to the user of the battery.

As shown in fig. 1, fig. 1 is a diagram illustrating an example of a location area of a lithium deposition location on a negative electrode tab when a lithium deposition phenomenon occurs. As can be seen from fig. 1, the lithium deposition sites are mainly located at the edge positions of the coating material in the negative electrode sheet.

In order to solve the above problem of safety caused by the reduction of the cell life due to the lithium separation phenomenon, as shown in fig. 2 and 3, an electrode sheet according to some embodiments of the present application includes: the current collector 110, and the first material layer 121 and the second material layer 122 disposed on the same side of the current collector 110; the second material layer 122 is disposed on at least one side of the first material layer 121 in the width direction of the current collector 110;

wherein the kinetic properties of the second material are higher than the kinetic properties of the first material; the first material is the material of the first material layer 121, and the second material is the material of the second material layer 122.

The electrode plate may be a negative electrode plate. Of course, in some possible embodiments, in order to avoid a possible lithium precipitation phenomenon of the positive electrode plate during the cell discharging process, the electrode plate may also be a positive electrode plate. In order to simplify the description, in the following embodiments, an electrode tab is mainly taken as an example of a negative electrode tab.

The electrode pad may include a current collector 110, and in general, the current collector 110 may refer to a structure for collecting current. For example, in a lithium battery, the current collector 110 may be a copper foil, an aluminum foil, or the like.

In this embodiment, the current collector 110 may include a surface thereon for disposing an electrode material. Accordingly, on the current collector 110, a first material layer 121 and a second material layer 122 may be disposed.

For example, one side surface of the current collector 110 may have a first region and a second region, the first material layer 121 may be disposed on the first region, and the second material layer 122 may be disposed on the second region. In other words, the first material layer 121 and the second material layer 122 may be disposed on the same side of the current collector 110. Of course, the descriptions of the first region and the second region are provided herein for facilitating understanding of the arrangement of the material layers on the current collector 110, and the number, shape or area of the first region and the second region may be determined according to actual needs.

In addition, the specific arrangement manner of the first material layer 121 and the second material layer 122 on the current collector 110 may be coating, lamination, heating and infiltration, and the like, and is not limited herein. For the sake of simplifying the description, the following description mainly illustrates the manner of coating.

The material of the first material layer 121 may be referred to as a first material, and the material of the second material layer 122 may be referred to as a second material. The first material has a lower kinetic performance than the second material.

For example, the first material and the second material may be at least one of energy storage materials of graphite, graphene, silicon material, and the like. For example, the first material and the second material may be soft carbon, hard carbon, graphite, lithium titanate, carbon nanotube, silicon, graphene, or other lithium intercalation and alloy materials.

The material systems of the first material and the second material can be the same or different, and the kinetic performance of the second material is ensured to be higher than that of the first material. For example, the first material and the second material are both materials of a material system of graphite, and the second material may be a material in which graphite is coated with some material having better anisotropy or a material in which graphite is doped with a material having better conductivity, as compared with the first material.

The current collector 110 may define a length direction and a width direction. For example, in general, the current collector 110 may have a rectangular shape, and the length direction thereof may refer to an extending direction of a longer side and the width direction thereof may refer to an extending direction of a shorter side. Of course, in some application scenarios, the current collector 110 in the molded battery cell may be in a winding form, and at this time, the width direction of the current collector 110 may correspond to the length direction of the molded battery cell.

As shown in fig. 2 and 3, the longitudinal direction of the current collector 110 may be represented by a direction L, and the width direction of the current collector 110 may be represented by a direction W.

In this embodiment, the second material layer 122 may be disposed on at least one side of the first material layer 121 in the width direction of the current collector 110.

For example, as shown in fig. 2, in one example, the second material layer 122 may be disposed on both sides of the first material layer 121 in the width direction of the current collector 110, that is, the second material layer 122 may occupy a plurality of areas in the current collector 110.

For simplicity of illustration, the area where the first material layer 121 is located may be referred to as a, and the two areas where the second material layer 122 is located may be referred to as B and C. Accordingly, the material coated in region a may be denoted as material a, i.e. the first material described above; the materials coated in regions B and C may be referred to as material B and material C, respectively, and both material B and material C may be considered the second material described above.

It is worth emphasizing again that in practical applications, the material is provided in each region, either by coating as in the above example, or by lamination, heat infiltration, for example.

The second material has high dynamic performance and high lithium ion diffusing capacity, so that the phenomenon of lithium precipitation caused by deposition is not easy to occur.

In the width direction of the current collector 110, the second material layer 122 is coated on both sides of the first material layer 121, that is, at the position where the lithium deposition phenomenon easily occurs as shown in fig. 1, the second material layer 122 with higher kinetic performance is replaced, so that the lithium deposition phenomenon can be effectively avoided.

Meanwhile, the second material layer 122 is made of a second material with relatively high dynamic performance, which helps to increase the charging rate.

In addition, since the second material layers 122 are disposed on both sides of the first material layer 121 in the width direction of the current collector 110, the second material layers 122 may extend along the length direction of the current collector 110 to cover more regions where lithium deposition may occur, thereby more effectively preventing the lithium deposition phenomenon.

As shown in fig. 3, in another example, the second material layer 122 may be disposed on one side of the first material layer 121 in a width direction of the current collector 110.

Similarly to the previous example, the area where the first material layer 121 is located may be denoted as a, and the two areas where the second material layer 122 is located may be divided into two areas denoted as B.

In this example, since the second material layer 122 with higher kinetic performance is disposed at a position where lithium deposition is likely to occur at the edge of the first material layer 121, the occurrence of lithium deposition can be effectively avoided. The detailed description of the specific principles is omitted here.

Of course, in some possible embodiments, the first material layer 121 may occupy a plurality of areas on the current collector 110, and thus, the first material layer 121 and the second material layer 122 may be alternately distributed in the width direction of the current collector 110.

The electrode sheet provided by the embodiment of the application includes a current collector 110, and a first material layer 121 and a second material layer 122 coated on the same side of the current collector 110, in the width direction of the current collector 110, the second material layer 122 is disposed on at least one side of the first material layer 121, and the dynamic performance of the second material layer 122 is higher than that of the first material layer 121; in this way, the second material layer 122 with high dynamic performance is disposed on at least one side of the first material layer 121, which helps to prevent the lithium deposition phenomenon from occurring at the edge of the first material layer 121, thereby improving the service life of the electrode plate.

In addition, the application of the second material layer 122 with higher dynamic performance also helps to improve the charging efficiency of the battery cell including the electrode plate.

In some examples, the energy density of the first material described above may be greater than the energy density of the second material.

With the electrode sheet shown in fig. 2, a second material having better conductivity is used at a position where lithium deposition easily occurs, so that the charging capability is improved while the occurrence of the lithium deposition phenomenon is avoided. The first material with higher energy density can be used at the middle part of the electrode pole piece while ensuring the corresponding charging capability. Therefore, lithium can be prevented from being separated at the position where the lithium separation frequently occurs on the electrode pole piece, and the improvement of the whole electric energy capacity of the battery cell comprising the electrode pole piece can be considered.

As shown in fig. 4, fig. 4 is an exemplary view of a cross section of the electrode pad shown in fig. 2. Here, the direction W in the drawing may also be used to indicate the width direction of the current collector 110, and the direction H may include the thickness direction of the current collector 110.

As can be seen in fig. 4, the first material layer 121 and the second material layer 122 may be one side surface coated in the thickness direction of the current collector 110, and both the first material layer 121 and the second material layer 122 may be directly coated on the current collector 110.

The portion of the second material layer 122 in the region B, the first material layer 121, and the portion of the second material layer 122 in the region C may be sequentially arranged along the width direction of the current collector 110.

Based on fig. 4, in some application scenarios, in the process of coating the material layer on the current collector 110, three coating ports sequentially arranged in the width direction of the current collector 110 may be used to simultaneously perform material spraying on the current collector 110, so as to improve the production efficiency of the electrode plate.

Of course, it is easily understood that fig. 4 is an example of a cross section of an electrode pad, and in practical applications, the second material layer 122 may be located on one side of the first material layer 121; alternatively, both side surfaces in the thickness direction of the current collector 110 may be coated with a material layer; alternatively, the boundary between the first material layer 121 and the second material layer 122 may have a certain inclination angle with respect to the thickness direction of the current collector 110, or the boundary may extend in a curved line, etc., which is not illustrated herein.

Similarly, in a vertical projection of a plane of the current collector 110, a boundary between the first material layer 121 and the second material layer 122 may be a straight line along a length direction of the current collector 110, or may be a curved line, a wavy line, a broken line, or a straight line having a preset included angle with respect to the length direction of the current collector 110, and the like, which is not specifically limited herein.

Optionally, the second material layer 122 includes a first sub-material layer 1221 and a second sub-material layer 1222; the first sub-material layer 1221 and the second sub-material layer 1222 are disposed on two sides of the first material layer 121,

the material of the first sub-material layer 1221 is the same as or different from the material of the second sub-material layer 1222.

As shown in fig. 2, the second material layer 122 may be disposed on both sides of the first material layer 121 in the width direction of the current collector 110. The second material layer 122 can be considered to be located in both regions B and C as shown in the figure.

Wherein the region B may correspond to the first sub-material layer 1221, and the region C may correspond to the second sub-material layer 1222. Accordingly, the material of the first sub-material layer 1221 may be denoted as material B, and the material of the second sub-material layer 1222 may be denoted as material C.

In this embodiment, the relative performance of the material B and the material C may not be limited, for example, the dynamic performance of the material B may be higher than, equal to, or lower than that of the material C.

When the width of the first sub material layer 1221 is denoted by W _ B and the width of the second sub material layer 1222 is denoted by W _ C, W _ B and W _ C may be equal to or different from each other. In addition, the shape of the first sub-material layer 1221 and the shape of the second sub-material layer 1222 may be the same or different, and are not limited in particular.

As indicated above, both material B and material C may be considered as the second material, which has higher kinetic properties than the first material. That is, the kinetic properties of material B and material C may be both higher than the kinetic properties of material a.

In this embodiment, the second material layer 122 includes the first sub-material layer 1221 and the second sub-material layer 1222 respectively disposed at two sides of the first material layer 121, so that the second material layer 122 can be coated on an area where a lithium deposition phenomenon is likely to occur as much as possible, thereby effectively avoiding the lithium deposition phenomenon.

Optionally, the electrode sheet further comprises a third material layer 123 coated on the current collector 110; the third material layer 123 is disposed on at least one side of the first material layer 121 in the length direction of the current collector 110;

the dynamic properties of the material of the third material layer 123 are higher than the dynamic properties of the first material.

As shown above, the position in the electrode tab where the lithium deposition phenomenon is likely to occur is generally at the edge position of the first material layer 121. In the above embodiment, by sequentially arranging the first material layer 121 and the second material layer 122 in the width direction of the current collector 110, the occurrence of the lithium deposition phenomenon may be effectively prevented.

In the present embodiment, in order to further prevent the occurrence of the lithium deposition phenomenon, a third material layer 123 with high dynamic performance may be disposed on at least one end of the first material layer 121 along the length direction.

As shown in fig. 5, fig. 5 is a view illustrating a structure example of an electrode pad including a first material layer 121, a second material layer 122, and a third material layer 123. Where the direction L may represent a length direction of the current collector 110, and the direction W may represent a width direction of the current collector 110.

As can be seen in fig. 5, the first material layer 121 may be regarded as a material layer mainly coated on the current collector 110, and in some application scenarios, the energy density of the first material may be higher to improve the electrical energy capacity of the battery cell including the electrode pole piece. Of course, the dynamic properties of the first material may also be relatively low.

The area where the first material layer 121 is located is denoted as a. The second material layer 122 may be disposed on both sides of the first material layer 121 in the width direction of the current collector 110, and areas where the second material layer 122 is located are denoted as B and C, respectively. The third material layer 123 may be disposed on both sides of the first material layer 121 in the length direction of the current collector 110, and regions where the third material layer 123 is located are denoted as D and E, respectively.

A. B, C, D and E are divided into materials denoted as material A, material B, material C, material D and material E. The material a corresponds to the first material, the materials B and C correspond to the second material, and the materials D and E correspond to the material of the third material layer 123, respectively, and are denoted as the third material.

The kinetic performance of the second material is higher than that of the first material, that is, the kinetic performance of the material B and the material C is higher than that of the material a, so as to effectively prevent the lithium deposition phenomenon from occurring on both sides of the first material layer 121 in the W direction.

Similarly, the kinetic performance of the third material is higher than that of the first material, i.e. the kinetic performance of both material D and material E is higher than that of material a, so as to effectively avoid the lithium deposition phenomenon on both sides of the first material layer 121 in the L direction.

The relative performance relationship between material D and material E may be not limited herein, that is, the dynamic performance of material D may be higher than or equal to the dynamic performance obtained by material E, and the material types of material D and material E may be the same or different.

Of course, in practical applications, the third material layer 123 may also be disposed on one side of the first material layer 121 in the length direction of the current collector 110.

In this embodiment, the third material layer 123 is disposed to further dispose the material layer with higher dynamic performance in the region where the lithium separation phenomenon may occur, so as to effectively avoid the occurrence of the lithium separation phenomenon in the electrode plate; in addition, the charging efficiency of the battery cell comprising the electrode pole piece is improved.

Optionally, the current collector 110 includes a single-sided region and a double-sided region oppositely arranged in a length direction;

both sides of the double-sided area in the thickness direction are coated with a first material layer 121 and a second material layer 122; one side in the thickness direction of the single-sided area is coated with a fourth material layer 124;

the dynamic properties of the material of the fourth material layer 124 are higher than the dynamic properties of the first material.

In combination with some application scenarios, the electrode sheet may need to be wound in a process of manufacturing a so-called battery cell. As shown above, both sides of the current collector 110 in the thickness direction may be coated with a material layer, and during the winding process of the electrode sheet, the material layers on both sides may generate a difference in the winding radius, that is, the length of the material layer on the outer side of the current collector 110 is greater than the length of the material layer on the inner side of the current collector 110.

Therefore, in general, the length of the material layer on one side of the current collector 110 is greater than the length of the material layer on the other side of the current collector 110, and at least a portion of the current collector 110 in the length direction is provided with the material layer only on one side.

As shown in fig. 6, a region where both sides of the current collector 110 are coated with the material layer may be referred to as a double-sided region (denoted as RD), and a region where only one side of the current collector 110 is coated with the material layer may be referred to as a single-sided region (denoted as RS). The direction L may represent a longitudinal direction of the current collector 110, and the direction H may represent a thickness direction of the current collector 110 (i.e., a thickness direction of the double-sided region or a thickness direction of the single-sided region).

Generally, the single-sided region RS may be located at one end of the current collector 110 in the length direction; alternatively, there may be a plurality of single-sided regions RS, and the single-sided regions RS and the double-sided regions RD are alternately arranged in the length direction of the current collector 110. In general, the single-sided region RS and the double-sided region RD may be considered to be disposed opposite to each other in the length direction of the current collector 110.

In combination with some application scenarios, in the electrode sheet processing process, the electrode sheet is usually cold-pressed under the condition that the coating of the material layer on the current collector 110 is completed. Due to the different thickness of the single area RS and the double area RD, the pressure experienced by the single area RS is generally less than the pressure experienced by the double area RD, resulting in a different compaction of the material layer of the single area RS than of the double area RD.

Generally, the difference in compaction also causes the phenomenon of lithium precipitation. For example, when both sides of the current collector 110 are coated with the same material layer, lithium deposition may occur in the single-sided region RS and the boundary between the single-sided region RS and the double-sided region RD.

In the present embodiment, in the double-sided region RD of the current collector 110, the first material layer 121 and the second material layer 122 may be disposed on both end surfaces in the thickness direction of the current collector 110 in the manner described in the above embodiments. And, in the single-sided region RS of the current collector 110, the fourth material layer 124 may be disposed at one end surface in the thickness direction thereof.

The dynamic performance of the material of the fourth material layer 124 is higher than that of the first material, that is, the fourth material layer 124 can be made of a material with a higher dynamic performance, so that the phenomenon of lithium precipitation in the single-sided region RS is effectively avoided, and the service life of the electrode plate is prolonged.

Of course, in order to further effectively avoid the lithium precipitation phenomenon at the boundary between the single-sided region RS and the double-sided region RD, the fourth material layer 124 may also be partially coated on the double-sided region RD of the current collector 110.

Fig. 7 and 8 are exemplary views of the location area of the fourth material layer 124 on the current collector 110. Where the direction L may represent a length direction of the current collector 110, and the direction W may represent a width direction of the current collector 110.

As shown above, the single-sided region RS may be located at one end in the length direction of the current collector 110; alternatively, there may be a plurality of single-sided regions RS, and the single-sided regions RS and the double-sided regions RD are alternately arranged in the length direction of the current collector 110.

Fig. 7 shows an exemplary view of a location area of the fourth material layer 124 in the case where the single-sided region RS is located at one end in the length direction of the current collector 110. As can be seen, the fourth material layer 124 may be located at one end of the length direction of the current collector 110.

Fig. 8 shows an exemplary view of a location area of the fourth material layer 124 in the case where the single-sided regions RS and the double-sided regions RD are alternately arranged in the length direction of the current collector 110. As can be seen, the fourth material layer 124 may be located at the middle of the length direction of the current collector 110.

Of course, in practical applications, the coating position of the fourth material layer 124 may also be selected according to the distribution of the single-sided region RS and the double-sided region RD on the current collector 110, which is not illustrated herein.

The embodiment of the present application further provides a method for manufacturing an electrode plate, as shown in fig. 9, the method includes:

step 901, providing a current collector, wherein one side surface of the current collector comprises a first area and a second area, and the second area is located on at least one side of the first area in the width direction of the current collector;

step 902, spraying a first material on the first area, and spraying a second material on the second area to obtain an electrode plate;

In the related art, it is common to take the area to be sprayed on the current collector as a whole, and during the spraying process, one material is sprayed on the whole area at one time.

Based on the existing spraying mode, if only one material is sprayed on the current collector, the requirements of balancing electric energy capacity and avoiding lithium precipitation are difficult to balance; when multiple materials are sprayed on the current collector, one material is usually sprayed and then another material is sprayed, so that the manufacturing efficiency of the electrode plate is low.

In this embodiment, one side surface of the current collector may include the first region and the second region, in other words, the first region and the second region may be located on the same surface of the current collector. Meanwhile, the second region is located on at least one side of the first region in a width direction of the current collector.

The first region and the second region may be considered to be regions on the current collector to be sprayed. Wherein a first material may be sprayed on the first area and a second material may be sprayed on the second area, and the kinetic properties of the second material are higher than the kinetic properties of the first material.

In other words, in this embodiment, there may be multiple areas on the current collector for spraying different materials, rather than the area for spraying the material as a whole. Thus, on the one hand, at least two materials with differences in kinetic properties can be sprayed on the current collector to balance the electrical energy capacity and avoid the need for lithium extraction; on the other hand, different materials can be synchronously sprayed on the current collector according to the requirement, so that the manufacturing efficiency of the electrode plate is improved.

In one example, the energy density of the first material may be greater than the energy density of the second material. That is, the first material may be a material having a relatively high energy density, thereby contributing to an increase in the electrical energy capacity of the cell including the electrode tab.

In general, the kinetic properties of the material with higher energy density tend to be relatively low, and in the case of the first material alone, it is easy to cause the lithium deposition at the position shown in fig. 1.

Thus, in this embodiment, the first material may be sprayed on the first region of the current collector while the second material may be sprayed on the second region of the current collector. The second region is located on at least one side of the first region in a width direction of the current collector.

If the first material layer is formed after the first material is sprayed on the first region and the second material layer is formed after the second material is sprayed on the second region, the second material layer can be considered to be located in the edge region of the first material layer where the lithium deposition phenomenon is likely to occur. The second material has high dynamic performance and high lithium ion diffusion capacity, so that the lithium ion deposition can be effectively avoided, and the phenomenon of lithium precipitation in the edge area can be effectively avoided.

In conclusion, the electrode piece manufactured by the electrode piece manufacturing method provided by the embodiment of the application can effectively balance the electric energy capacity and avoid the requirement of lithium precipitation.

As for the specific structure of the electrode plate obtained by the manufacturing method, refer to fig. 2 and fig. 3 and the corresponding embodiments, which are not described herein again. Of course, in practical applications, the electrode plate shown in fig. 4 to 8 and related embodiments can be obtained by further processing on the basis of the electrode plate, and details are not described here.

Optionally, spraying the first material in the first area and spraying the second material in the second area are performed simultaneously.

For ease of understanding, the following description will be given primarily in terms of a process for making an electrode pad as shown in fig. 2.

As shown in fig. 10, fig. 10 is a schematic diagram of the fabrication of the electrode pad shown in fig. 2 using a fabrication apparatus. The fabrication apparatus may include three coating ports, denoted coating port a, coating port B, and coating port C, for spraying material a, material B, and material C, respectively.

The material a may correspond to the first material, and the materials B and C may correspond to the second material. That is, the dynamic performance of material B and the dynamic performance of material C may be higher than that of material a, and the relative performance relationship between material B and material C is not particularly limited herein.

The current collector 200 includes a first region 210 and a second region, wherein the second region may specifically include a first sub-region 221 and a second sub-region 222, and the first sub-region 221 and the second sub-region 222 are respectively located on two sides of the first region 210 in a width direction (denoted as a direction W).

When the spraying operation shown in step 902 is performed, the first sub-area 221, the first area 210, and the second area may face the coating port a, the coating port B, and the coating port C, respectively. During the movement of the length direction (noted as direction L) of the current collector 200 relative to each coating port, each coating port may simultaneously inject material into a corresponding area on the current collector 200 to form a corresponding material layer on the current collector 200.

Of course, the injection of material from each coating port described herein at the same time may be understood as the simultaneous processing of the first material layer and the second material layer described above on the current collector 200. In practical applications, one or more of the coating ports may be selectively opened or closed according to the distribution of the first region 210 and the second region on the current collector 200. For example, when the fourth material layer shown in fig. 8 needs to be disposed on the current collector 200, the coating port a may be closed when the coating port a passes through a region of the current collector 200 corresponding to the fourth material layer.

In addition, the current collector 200 moves relative to each coating opening along the length direction thereof, and the current collector 200 may be actively moved, or each coating opening may be actively moved, or the current collector 200 and the coating openings may simultaneously move towards each other, and the like, and is not particularly limited herein.

In one example, if the spraying widths corresponding to the coating opening a, the coating opening B, and the coating opening C are respectively denoted as W _ A, W _ B and W _ C, W _ a > W _ B may be set, and W _ a > W _ C, so that the first material with high energy density is sprayed as much as possible while the phenomenon of lithium precipitation at the edge of the formed first material layer is avoided, thereby improving the electric energy capacity of the battery cell including the manufactured electrode tab.

The above example is directed to the electrode sheet manufacturing equipment, i.e. the manufacturing process, used when the electrode sheet shown in fig. 2 is processed. In practical application, when the electrode plate shown in fig. 3 or other similar electrode plates need to be processed, the number or position of the coating openings in the electrode plate manufacturing equipment can be adjusted according to needs. In general, however, a plurality of coating openings may be sequentially arranged along the width direction of the current collector to be sprayed, so that spraying of the first material in the first area and spraying of the second material in the second area are performed simultaneously, and the processing efficiency of the electrode plate is improved.

The embodiment of the present application further provides a battery cell, which includes a positive pole piece 310, a negative pole piece 320, and a diaphragm 330, as shown in fig. 11, the positive pole piece 310 and the negative pole piece 320 are respectively connected to two sides of the diaphragm 330 in the thickness direction;

the negative electrode tab 320 is the electrode tab described above.

In other words, in the battery cell provided in this embodiment, the negative electrode tab 320 may include a current collector, and a first material layer 322 and a second material layer 323 coated on the current collector; the second material layer 323 is disposed on at least one side of the first material layer 322 in the width direction of the current collector;

wherein the kinetic properties of the second material are higher than the kinetic properties of the first material; the first material is the material of the first material layer 322, and the second material is the material of the second material layer 323.

As shown in fig. 11, the thickness direction of the separator 330 may be the same as the thickness direction of the current collector, and may be represented by a direction H; the width direction of the current collector can be regarded as the direction vertical to the paper surface; the longitudinal direction of the current collector can be represented by the direction L.

It should be noted that the implementation manner of the electrode plate embodiment is also applicable to the embodiment of the battery cell, and can achieve the same technical effect, and details are not described herein.

In some examples, the battery cell may be applied to an electronic device, and the electronic device may be a mobile phone, a tablet computer, a notebook computer, a palm top computer, a vehicle-mounted electronic device, a wearable device, an ultra-mobile personal computer (UMPC), a netbook, or a Personal Digital Assistant (PDA), and the like.

Of course, in other examples, the battery cell may also be applied to electric devices such as vehicles and robots, which are not listed here.

Optionally, a vertical projection of the first end 311 of the positive pole piece 310 on the separator 330 is located in a vertical projection of the second material layer 323 of the negative pole piece 320 on the separator 330; the first end 311 is at least one end of the positive electrode tab 310 in the width direction.

As indicated above, the electrode pole pieces may be in a wound state in a cell, and accordingly, in such a cell, the positive pole piece 310, the negative pole piece 320, and the separator 330 may all be in a wound state. In the present embodiment, the vertical projections of the positive electrode plate 310 and the negative electrode plate 320 on the separator 330 can be understood as the vertical projections in the flattened state to some extent.

Alternatively, in the wound state, the positive electrode sheet 310 and the negative electrode sheet 320 and the separator 330 therebetween may be considered to have a one-to-one correspondence in the longitudinal direction of the electrode sheets. The vertical projection of the electrode pads on the separator can be considered as the projection of the electrode pads on the corresponding separators 330 along the normal direction of the corresponding separators 330.

For simplicity, the length direction of the electrode pad can be referred to as direction L, the width direction of the electrode pad can be referred to as direction W, and the thickness direction of the electrode pad can be referred to as direction H.

In general, the width of negative pole piece 320 may be greater than the width of positive pole piece 310, and the vertical projection of negative pole piece 320 on separator 330 may be overlaid on the vertical projection of positive pole piece 310 on separator 330.

As shown in fig. 12, in one example, the first end 311 of the positive pole piece 310 may refer to two ends in the direction W, and the second material layer 323 of the negative pole piece 320 may be located in two regions, i.e., region B and region C.

On the side of the region B, the width of the negative electrode plate 320 beyond the positive electrode plate 310 may be denoted as Δ WB, and the width of the region B may be denoted as W _ B, so that the relationship W _ B is greater than or equal to Δ WB, and thus, the vertical projection of the corresponding end of the positive electrode plate 310 on the side of the region B on the diaphragm 330 may fall into the vertical projection of the region B on the diaphragm 330.

Similarly, on the side of the region C, the width of the negative electrode plate 320 beyond the positive electrode plate 310 may be denoted as Δ WC, and the width of the region C may be denoted as W _ C, and then there may be a relationship W _ C ≧ Δ WC, so that the vertical projection of the corresponding end of the positive electrode plate 310 on the side of the region C on the separator 330 may fall into the vertical projection of the region C on the separator 330.

As indicated above, the second material used for the second material layer 323 may have higher dynamic properties. In the vertical projection of the separator 330, the first end 311 of the positive electrode pole piece 310 is covered by the area where the second material layer 323 is located, so that the lithium separation phenomenon in the area corresponding to the first end 311 on the negative electrode pole piece 320 can be effectively avoided, and the service life of the battery cell is prolonged.

Of course, in conjunction with fig. 3, the second material layer 323 may be only located in the region B or the region C, and accordingly, the first end 311 of the positive electrode sheet 310 may refer to an end on the same side as the second material layer 323 in the direction W. Alternatively, the second material layer 323 may be located in the above-described region B and region C, but the first end 311 of the positive electrode tab 310 may refer to any one end in the direction W, and so on.

Optionally, the negative pole piece 320 further includes a third material layer 324;

a perpendicular projection of second end 312 of positive pole piece 310 onto separator 330, lying in a perpendicular projection of third material layer 324 onto separator 330; the second end 312 is at least one end of the positive electrode sheet 310 in the length direction.

In general, the length of negative pole piece 320 may be greater than the length of positive pole piece 310, and the vertical projection of negative pole piece 320 on separator 330 may be overlaid on the vertical projection of positive pole piece 310 on separator 330.

Referring to fig. 13, the third material layer 324 may be located in the regions D and E, and the second end 312 may be two ends of the positive electrode sheet 310 in the length direction.

On the side of the region D, the length of the negative electrode plate 320 beyond the positive electrode plate 310 may be denoted as Δ LD, and the length of the region D may be denoted as L _ D, and then there may be a relationship L _ D ≧ Δ LD, so that the vertical projection of the corresponding end of the positive electrode plate 310 on the side of the region D on the diaphragm 330 may fall into the vertical projection of the region D on the diaphragm 330.

Similarly, on the side of the region E, the length of the negative electrode sheet 320 beyond the positive electrode sheet 310 may be denoted as Δ LE, and the length of the region E may be denoted as L _ E, and then there may be a relationship L _ E ≧ Δ LE, so that the vertical projection of the corresponding end of the positive electrode sheet 310 on the side of the region E on the separator 330 may fall into the vertical projection of the region E on the separator 330.

Similar to the previous embodiment, in the present embodiment, the lithium separation phenomenon in the region of the negative electrode tab 320 corresponding to the second end 312 can be effectively avoided, and the service life of the battery cell is prolonged.

Of course, in practical applications, the second end 312 of the positive electrode 310 may also refer to any end in the direction L, which is not described herein.

Optionally, the battery cell further includes a negative electrode tab 340, the negative electrode tab 340 is connected to the third region of the first current collector 321, and the first current collector 321 is a current collector included in the negative electrode tab 320;

in the case where the third region is adjacent to the first region, a region of the third region near the first region is coated with a fifth material layer 325;

wherein the first region is a region on which the first material layer 322 is coated on the first current collector 321; the kinetic properties of the material of the fifth material layer 325 are higher than the kinetic properties of the first material.

The negative electrode tab 340 may be a current collector electrically connected to the negative electrode sheet 320, i.e., the first current collector 321, and the area where the first current collector 321 is connected to the negative electrode tab 340 may correspond to the third area (marked as R3 in the figure).

In general, the length direction of the negative electrode tab 340 may be the same as the width direction of the negative electrode tab 320, and therefore, the third region for connecting the negative electrode tab 340 may reach the width range of the first region (marked as R1 in the figure) in the direction W.

The first material layer 322 is coated on the first region, and the first material layer 322 has relatively low dynamic performance, so that if the first material layer 322 is directly adjacent to the third region, lithium deposition easily occurs in the adjacent region.

Therefore, as shown in fig. 14, in the present embodiment, in the case where the third region R3 is adjacent to the first region R1, the fifth material layer 325 is coated on a region of the third region R3 close to the first region R1. The dynamic performance of the material of the fifth material layer 325 is higher than that of the first material, so that the lithium separation phenomenon in the adjoining area of the third area R3 and the first area R1 can be effectively avoided, and the service life of the battery cell is prolonged.

Optionally, the battery cell further includes a positive electrode paste 350, and the positive electrode paste 350 is connected to the fourth region of the first current collector 321;

in the case where the fourth region is contiguous with the first region, a region of the fourth region near the first region is coated with a sixth material layer 326;

wherein the kinetic properties of the material of the sixth material layer 326 are higher than the kinetic properties of the first material.

The current collector included in the positive electrode plate 310 is defined as a second current collector, and generally, a positive electrode tab is connected to the second current collector, and a positive electrode paste 350 is generally disposed on the first current collector 321 at a position corresponding to the positive electrode tab.

The positive electrode tab 310 may be specifically attached to a fourth region (labeled as R4 in the figure) of the first current collector 321, similar to the third region R3 described above, the fourth region R4 may also be adjacent to the first region R1 coated with the first material layer 322. And lithium deposition is likely to occur in the adjacent region.

Therefore, as shown in fig. 14, in the present embodiment, in the case where the fourth region R4 is contiguous to the first region R1, the sixth material layer 326 is coated on a region of the fourth region R4 close to the first region R1. The dynamic performance of the material of the sixth material layer 326 is higher than that of the first material, so that the lithium separation phenomenon in the adjacent region between the fourth region R4 and the first region R1 can be effectively avoided, and the service life of the battery cell is prolonged.

It should be noted that the materials of the second material layer 324, the fifth material layer 325, and the sixth material layer 326 may be the same or different, and are not limited herein.

In the description herein, reference to the description of the terms "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the present application have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the application, the scope of which is defined by the claims and their equivalents.

Claims

1. An electrode sheet, comprising: the current collector comprises a current collector, a first material layer and a second material layer, wherein the first material layer and the second material layer are arranged on the same side of the current collector; the second material layer is arranged on at least one side of the first material layer in the width direction of the current collector;

2. The electrode tab of claim 1, wherein the second material layer comprises a first sub-material layer and a second sub-material layer; the first sub-material layer and the second sub-material layer are respectively arranged at two sides of the first material layer,

the material of the first sub-material layer is the same as or different from the material of the second sub-material layer.

3. The electrode tab of claim 1, further comprising a third material layer disposed on the current collector; the third material layer is arranged on at least one side of the first material layer in the length direction of the current collector;

the material of the third material layer has a higher dynamic performance than the dynamic performance of the first material.

4. The electrode sheet of claim 1, wherein the current collector comprises a single-sided area and a double-sided area oppositely arranged in a length direction;

the first material layer and the second material layer are arranged on two sides of the double-face area in the thickness direction; a fourth material layer is arranged on one side of the single-surface area in the thickness direction;

the dynamic performance of the material of the fourth material layer is higher than that of the first material.

5. A manufacturing method of an electrode plate is characterized by comprising the following steps:

6. A battery cell is characterized by comprising a positive pole piece, a negative pole piece and a diaphragm, wherein the positive pole piece and the negative pole piece are respectively connected to two sides of the diaphragm in the thickness direction;

the negative electrode plate is the electrode plate as claimed in any one of claims 1 to 4.

7. The cell of claim 6, wherein a vertical projection of the first end of the positive pole piece on the separator is located in a vertical projection of the second material layer of the negative pole piece on the separator; the first end is at least one end of the positive pole piece in the width direction.

8. The cell of claim 6, wherein the negative pole piece further comprises a third layer of material;

the vertical projection of the second end part of the positive pole piece on the diaphragm is positioned in the vertical projection of the third material layer on the diaphragm; the second end is at least one end of the positive pole piece in the length direction.

9. The cell of claim 6, further comprising a negative tab connected to a third region of the first current collector, the first current collector being a current collector comprised by the negative pole piece;

under the condition that the third area is adjacent to the first area, a fifth material layer is arranged on the area, close to the first area, of the third area;

the first region is a region provided with a first material layer on the first current collector; the kinetic properties of the material of the fifth material layer are higher than the kinetic properties of the first material.

10. The cell of claim 6, further comprising a positive paste, the positive paste being connected to the fourth region of the first current collector;

under the condition that the fourth area is adjacent to the first area, a sixth material layer is arranged on the area, close to the first area, of the fourth area;

wherein the kinetic performance of the material of the sixth material layer is higher than the kinetic performance of the first material.