CN220209011U - Pole piece structure, battery core and lithium ion battery - Google Patents

Abstract

The application relates to a pole piece structure, an electric core and a lithium ion battery. The pole piece structure comprises a current collector, wherein the current collector is provided with a first side face and a second side face which are opposite to each other, and an active material layer is arranged on the first side face and/or the second side face; a tab protruding in a width direction of the current collector at a side edge of the current collector; the stabilizing layer is arranged on the electrode lug and is positioned in a region, close to the current collector, of the electrode lug. According to the scheme provided by the application, the phenomenon that the lug is easy to collapse and turn over in the related technology is avoided.

Description

Pole piece structure, battery core and lithium ion battery

Technical Field

The application relates to the technical field of new energy, in particular to a pole piece structure, an electric core and a lithium ion battery.

Background

When the coiled lithium ion battery is manufactured, the pole pieces are stacked together according to the sequence of the diaphragm, the negative pole piece, the diaphragm and the positive pole piece, and then the coiled lithium ion battery is coiled from the head to the tail by taking the head of the negative pole piece as the center to form a coiled core.

In the related art, in some multi-lug lithium ion batteries, a plurality of lugs extend out of the side edges of a pole piece along the length direction, and as the foil material of the pole piece is thinner, the lugs on the pole piece are easy to fold and collapse into a winding core, so that the safety problems such as short circuit and the like of the battery can be caused; in addition, as the active material on the pole piece is of a gap coating structure, a single-sided area exists, and the pole lugs are not arranged in the single-sided area of the related technology, so that the impedance of the single-sided area is larger than that of the double-sided area, and the lithium precipitation risk is higher.

Disclosure of Invention

In order to solve or partially solve the problems existing in the related art, the application provides a pole piece structure, an electric core and a lithium ion battery, so that the phenomenon that pole lugs collapse and turn over easily in the related art is avoided, meanwhile, the impedance of a single-sided area can be reduced, and further the lithium separation risk is reduced.

A first aspect of the present application provides a pole piece structure comprising:

a current collector having first and second opposite sides, the first and/or second sides being provided with an active material layer;

a tab protruding in a width direction of the current collector at a side edge of the current collector;

and the stabilizing layer is arranged in the area of the tab close to the current collector.

In one embodiment of the present utility model, a method for manufacturing a semiconductor device,

the tab is provided with a plurality of tabs.

In one embodiment, the stabilizing layer is an adhesive layer;

the material of the stabilizing layer is a hot-melt material, and the adhesive force of the hot-melt material is activated at a preset temperature.

In one embodiment, after the current collector is wound, the adhesive force of the hot-melt material is activated in the hot-pressed state at the preset temperature, and adjacent tabs among the tabs arranged in the same direction are adhered by the hot-melt material.

In some embodiments, the current collector has a single-sided region and a double-sided region;

in the single-sided region, the active material layer is provided on the first side or the second side of the current collector; in the double-sided region, the active material layer is disposed on the first side and the second side of the current collector; the plurality of tabs are arranged on the side edges of the current collector and correspond to the single-sided area and the double-sided area.

In one embodiment, the stabilizing layer has the same thickness as the active material layer; or (b)

The thickness of the stabilizing layer is 20-50um;

the height of the stabilizing layer is 1/3-5/6 of the height of the tab.

The pole piece structure is a negative pole piece.

A second aspect of the present application provides a cell comprising:

the pole piece structure as described in the first aspect above.

In one embodiment, the battery cell is a wound coil core, and the battery cell includes:

a positive plate, a negative plate, and a separator between the positive plate and the negative plate;

the positive plate, the diaphragm and the negative plate are overlapped and are wound from the head to the tail to form a winding core.

A third aspect of the present application provides a lithium ion battery comprising:

a housing; and

the battery cell of the second aspect above, wherein the battery cell is encapsulated in the housing.

The technical scheme that this application provided can include following beneficial effect:

the pole piece structure that this application provided, the pole lug is close to the regional stable layer that is equipped with of at least part of current collector, and stable layer has the supporting role to the pole lug, can avoid the pole lug to collapse and turn over.

The pole piece structure that this application provided, single face district and two-sided district all have can set up the utmost point ear, and the stable layer can be stable for the position of current collector to a plurality of utmost point ears in single face district, can reduce the impedance in single face district, and then has reduced the lithium risk of separating out.

The pole piece structure that this application provided, the stabilizing layer be the adhesive layer, and the material of adhesive layer is hot melt material, consequently when the coiling is accomplished and is carried out hot pressing, the adhesion of hot melt material is activated, can make neatly bond together between a plurality of lugs of following same direction range, has further avoided collapsing and turning over of tab effectively.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application.

Drawings

The foregoing and other objects, features and advantages of the application will be apparent from the following more particular descriptions of exemplary embodiments of the application as illustrated in the accompanying drawings wherein like reference numbers generally represent like parts throughout the exemplary embodiments of the application.

FIG. 1 is a schematic structural view of a pole piece structure according to an embodiment of the present application;

FIG. 2 is a cross-sectional view of the pole piece structure shown in the embodiment of FIG. 1, taken along line C-C;

fig. 3 is a schematic structural diagram of a battery cell according to an embodiment of the present application.

Reference numerals: 100. a positive plate; 110. a current collector; 111. an active material layer; 112. a stabilization layer; 113. a negative electrode tab; 210. a positive electrode tab; 114. a first empty foil region; 115. a second empty foil region; 200. a negative electrode sheet; 300. a diaphragm.

Detailed Description

Preferred embodiments of the present application will be described in more detail below with reference to the accompanying drawings. While the preferred embodiments of the present application are shown in the drawings, it should be understood that the present application may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

The terminology used in the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. As used in this application and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any or all possible combinations of one or more of the associated listed items.

It should be understood that although the terms "first," "second," "third," etc. may be used herein to describe various information, these information should not be limited by these terms. These terms are only used to distinguish one type of information from another. For example, a first message may also be referred to as a second message, and similarly, a second message may also be referred to as a first message, without departing from the scope of the present application. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

In the description of the present application, it should be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate orientations or positional relationships based on the orientation or positional relationships shown in the drawings, merely to facilitate description of the present application and simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present application.

Unless specifically stated or limited otherwise, the terms "mounted," "connected," "secured" and the like should be construed broadly, as they may be fixed, removable, or integral, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art as the case may be.

In the related art, in some multi-lug lithium ion batteries, a plurality of lugs extend out of the side edges of a pole piece along the length direction, and as the foil material of the pole piece is thinner, the lugs on the pole piece are easy to fold and collapse into a winding core, so that the safety problems such as short circuit and the like of the battery can be caused; in addition, as the active material on the pole piece is of a gap coating structure, a single-sided area exists, and the pole lugs are not arranged in the single-sided area of the related technology, so that the impedance of the single-sided area is larger than that of the double-sided area, and the lithium precipitation risk is higher.

According to the pole piece structure, the phenomenon that the pole lugs are easy to collapse and fold in the related art is avoided, meanwhile, the impedance of a single-face area can be reduced, and then the lithium separation risk is reduced.

The following describes the technical scheme of the embodiments of the present application in detail with reference to the accompanying drawings.

FIG. 1 is a schematic structural view of a pole piece structure according to an embodiment of the present application; fig. 2 is a cross-sectional view of the pole piece structure shown in the embodiment of fig. 1, along C-C, see fig. 1.

Referring to fig. 1 and 2, the pole piece structure provided in the present application includes:

the current collector 110, the current collector 110 has a first side and a second side opposite to each other, and the first side and/or the second side is provided with an active material layer 111.

A tab 113 protruding in the width direction of the current collector 110 at a side edge of the current collector 110;

the stabilizing layer 112 is disposed on the tab 113, and is located in a region of the tab 113 near the current collector 110.

In the related art, the foil used for die-cutting the current collector and the tab is thinner, the tab is softer after die-cutting, bending or folding is easy to occur, and the scheme provided by the embodiment has the advantages that the tab 113 is provided with the stabilizing layer in the area close to the current collector 110, and the stabilizing layer has a supporting effect on the tab 113, so that the tab 113 can be prevented from bending and folding.

In some embodiments, a plurality of tabs 113 are provided, and the plurality of tabs 113 are spaced apart in the length direction of the current collector 110.

In this embodiment, the current collector 110 has a single-sided region a and a double-sided region B; in the single-sided region a, the active material layer 111 is provided on the first side or the second side of the current collector 110; in the double-sided region B, the active material layer 111 is provided on the first side and the second side of the current collector 110.

Referring to fig. 1 and 2, the single-sided area a is an area within the rectangular dotted line in fig. 1, and also an area shown as L1 in fig. 2, and the double-sided area is an area shown as L3 in fig. 2. The pole piece structure shown in fig. 1 is in a pre-die cut state, and the rectangular dotted line at the edge of the current collector 110 in fig. 1 is a die cut line, and a plurality of tabs 113 can be formed after die cutting along the dotted line. The single-sided region a means that one side of the current collector 110 has the active material layer 111, and the other side corresponding thereto does not have the active material layer 111.

In the related art, after the current collector 110 is cut or wound, the single-sided region a is curled due to different tensions of both sides of the single-sided region a, and if the tab 113 is provided in the single-sided region a, the tab 113 of the single-sided region a is easily collapsed and folded, and thus a battery short circuit is easily caused, so that the tab 113 is not normally provided in the single-sided region a in the related art. However, if the tab 113 is not provided in the single-sided region a, the single-sided region a has a larger impedance than other regions of the current collector 110, resulting in uneven current distribution of the pole piece and a risk of lithium precipitation in the single-sided region a.

The pole piece structure that this application provided, stabilizing layer 112 have the stabilization to a plurality of utmost point ears 113, have avoided appearing collapsing and turning over after utmost point ear 113 cross cutting or winding, therefore single face district A and double sided district B all can set up utmost point ear 113, have reduced single face district A's impedance, have reduced lithium battery's lithium risk of separating out, have promoted the electrochemical performance of electric core.

It should be noted that the electrode sheet structure of this embodiment is a negative electrode sheet. In the related art, as the negative electrode plate is thinner than the foil of the positive electrode plate, and the single-sided area is inside the battery cell, the tab in the single-sided area is easier to fold into the battery cell, and the tab of the negative electrode plate can be effectively prevented from folding into the battery cell.

The active material layer 111 contains an active material for generating an electric current. The current collector 110 is a metal foil such as copper foil or aluminum foil, and is used for collecting current generated by the active material in the active material layer 111.

In some embodiments, the tab 113 may be formed by cutting a part of the current collector 110, where the active material layer 111 is not disposed, through a film, or the tab 113 may be welded to a separate component of the current collector 110, where the tab 113 is used to guide out the current collected on the current collector 110.

In the related art, when a battery is charged, lithium ions are released from a positive plate and then are inserted into a negative plate after passing through a diaphragm, and when abnormal factors cause that the released lithium ions of the positive plate cannot be inserted into the negative plate, the surface of the negative plate can separate out the lithium ions, and the phenomenon is called "lithium separation". The lithium precipitation not only reduces the battery performance and shortens the cycle life greatly, but also limits the quick charge capacity of the battery, and can cause disastrous consequences such as combustion, explosion and the like.

According to the scheme, through the arrangement of the stabilizing layer 112, the lug 113 can be arranged in the single-sided area A, namely, the single-sided area A and the double-sided area B are provided with the lug 113, current generated in the single-sided area A can be directly guided to the anode and the cathode of the battery through the lug 113 of the single-sided area A without being conducted through the lug 113 of the double-sided area B, and therefore the situation of uneven current distribution on the pole piece can be effectively improved, and the lithium precipitation phenomenon of the single-sided area A is improved.

In this embodiment, the stabilizing layer 112 of the single-sided area a may be disposed on the plurality of tabs 113 in an area close to the current collector 110. Therefore, after the pole piece is wound, the stabilizing layer 112 can be filled between every two adjacent pole lugs 113 aligned along the same straight line (as in the straight line L in fig. 3), so that the pole lugs 113 can form mutual support in the arrangement direction, the form stability of the pole lugs 113 relative to the current collector 110 is ensured, collapse and turnover can not occur, the pre-welding of the pole lugs 113 is replaced by the arrangement, and the production efficiency of the battery core is improved.

In some embodiments, the stabilizing layer 112 is an adhesive layer, the adhesive layer may be disposed on the current collector 110 by a coating method, the material of the adhesive layer is a hot-melt material, and the adhesive force of the hot-melt material is activated at a preset temperature. After the completion of the hot pressing after the completion of the winding, the adhesive force of the hot-melt material is activated, and the plurality of tabs 113 aligned in the same line are bonded together in order.

In some embodiments, the bonding force of the heat-fusible material is in an inactive state (i.e., the bonding force is smaller than that of the active state or no bonding force) before the current collector 110 is wound, and bonding of the plurality of tabs 113 in a misaligned state can be avoided before hot pressing.

In some embodiments, after the current collector 110 is wound, the hot-melt material is activated in a hot-press state at a preset temperature, and among the plurality of tabs 113 arranged along the same line, adjacent tabs 113 are bonded by the hot-melt material, so that the relative positions of the plurality of tabs 113 are stabilized. In this embodiment, the hot pressing temperature may be 75 to 85 degrees, for example, 80 degrees, but is not limited thereto.

It is understood that the stabilizing layer 112 may not be limited to an adhesive layer, and in some embodiments, the stabilizing layer 112 may be a coating layer without tackiness, or the stabilizing layer 112 may be an adhesive member attached to the tab 113, and the adhesive member may be, for example, adhesive paper.

In this embodiment, the stabilization layer 112 is not in contact with the active material layer 111, or the stabilization layer 112 is not overlapped with the active material layer 111. The stabilizer layer 112 and the active material layer 111 have a gap therebetween in the width direction of the current collector 110, and the gap is 0 to 1mm. After the arrangement, when the die cutting is carried out, the die cutting can be carried out along the junction of the stabilizing layer 112 and the active material layer 111, so that the hot-melt materials of the stabilizing layer 112 are basically all on the electrode lugs and cannot be remained in the active material layer 111, and the performance of the battery cell is prevented from being influenced after the hot-melt materials are adhered to the diaphragm.

In this embodiment, the hot-melt material may include at least one of EVA (ethylene-vinyl acetate copolymer, vinyl acetate copolymer), polyolefin, PA (Polyamide), polylactic acid, but is not limited thereto.

Referring to fig. 2, the first and second sides of the current collector 110 are formed with first and second empty foil regions 114 and 115, respectively, the empty foil regions being regions on the current collector 110 where the active material layer 111 is not coated, and the empty foil regions being formed by gap coating of the active material layer 111 on the current collector 110 along the length direction of the current collector 110.

The first empty foil region 114 is also a region indicated by L5 in fig. 2, the second empty foil region 115 is also a region indicated by L2 in fig. 2, the spacing L5 between the active material layers of the first empty foil region 114 is larger than the spacing L2 between the active material layers of the second empty foil region 115, i.e. L5 is larger than L2, so that the first empty foil region 114 is also referred to as a long gap region, and the second empty foil region is also referred to as a short gap region, wherein the length L3 of the active material layer on one side of the first empty foil region 114 may be smaller than the length L4 of the active material layer 111 on one side of the second empty foil region 115, such that the projection of a part of the active material layer 111 on one side of the second empty foil region 115 is forward to the first empty foil region 114 on the other side, which part is a single-sided region a in fig. 2, the length of the single-sided region a being L1.

In some embodiments, the stabilizing layer 112 is disposed on the plurality of tabs 113 on the side of the first empty foil region 114, and the stabilizing layer 112 may not be disposed on the plurality of tabs 113 on the side of the second empty foil region 115.

In some embodiments, the stabilizing layer 112 is disposed on the plurality of tabs 113 on the side of the second empty foil region 115, and the stabilizing layer 112 may not be disposed on the plurality of tabs 113 on the side of the first empty foil region 114.

In some embodiments, the stabilizing layer 112 is disposed on both sides of the first hollow foil region 114 and the second hollow foil region 115 on the plurality of tabs 113.

In this embodiment, the height of the stabilizing layer 112 and the height of the tab 113 have a set ratio, and the height of the stabilizing layer 112 is smaller than the height of the tab 113.

In some embodiments, the height of the stabilizing layer 112 is 1/3 to 5/6 of the height of the tab 113, for example, the height of the tab 113 may be 6mm and the height of the stabilizing layer 112 may be 3mm.

In some embodiments, the tab 113 may have a height of 8-12mm, such as 10mm, before die cutting, and a height of 6mm after die cutting.

In some embodiments, the end of the tab 113 away from the current collector 110 is a welded portion (not shown), the sum of the height of the stabilizing layer 112 and the height of the welded portion is less than or equal to the height of the tab 113, for example, the height of the welded portion is 3mm, the height of the stabilizing layer 112 is 3mm, and the height of the tab is 6mm.

In some embodiments, the stabilizing layer 112 may be the same thickness as the active material layer 111, and the stabilizing layer may be 20-50um thick.

The tab structure provided by the embodiment of the application is introduced above, and correspondingly, the application also provides a battery cell which comprises the features of the pole piece structure described in the embodiment above.

Fig. 3 is a schematic structural view of a winding core according to an embodiment of the present application.

Referring to fig. 1-3, an embodiment of the present application provides a winding core with a wound battery core, the winding core includes a positive electrode sheet 100, a negative electrode sheet 200, and a separator 300 between the positive electrode sheet 100 and the negative electrode sheet 200;

the positive electrode sheet 100, the separator 300, and the negative electrode sheet 200 are stacked and wound from the head to the tail to form a winding core.

In this embodiment, the plurality of negative electrode tabs 113 on the positive electrode tab 100 are arranged along the same straight line L, and the plurality of positive electrode tabs 210 on the negative electrode tab 200 are arranged along another straight line parallel to the straight line L.

In some embodiments, the stabilizing layer is an adhesive layer, after the pole piece structure is hot-pressed after winding, the adhesive force of the hot-melt material is activated, the hot-melt material can be filled between every two adjacent pole lugs 113 arranged along the same straight line, the pole lugs 113 are orderly bonded together by the hot-melt material, the pole lugs 113 keep a stable state relative to the position of the winding core, and the pole lugs 113 cannot collapse or be folded into the winding core.

According to the battery cell provided by the embodiment, the single-sided area A and the double-sided area B are provided with the lugs 113, the stable layer 112 can stabilize the positions of the lugs 113 of the single-sided area A, collapse and turnover of the lugs 113 are avoided, tension difference of the single-sided area A is properly counteracted, the lugs 113 can be arranged in the single-sided area A, impedance of the single-sided area A is reduced, lithium separation risk is reduced, and electrochemical performance of the battery cell is improved.

Correspondingly, the application also provides a lithium ion battery, which comprises: a housing; and the battery cell of the embodiment is encapsulated in the shell. The features of the battery cell of this embodiment may be referred to the description of the above embodiments, and will not be repeated here.

The lithium ion battery provided by the application not only can avoid the turnover and collapse of the lug 113, but also can set the lug 113 in the single-sided area A, so that the impedance of the single-sided area A is reduced, the lithium separation risk is reduced, and the electrochemical performance of the lithium ion battery is improved.

The embodiments of the present application have been described above, the foregoing description is exemplary, not exhaustive, and not limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the various embodiments described. The terminology used herein was chosen in order to best explain the principles of the embodiments, the practical application, or the improvement of technology in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.

Claims (10)

1. A pole piece structure, comprising:

a current collector having first and second opposite sides, the first and/or second sides being provided with an active material layer;

a tab protruding in a width direction of the current collector at a side edge of the current collector;

the stabilizing layer is arranged on the tab and is positioned in a region of the tab, which is close to the current collector.

2. A pole piece structure according to claim 1, characterized in that:

the tab is provided with a plurality of tabs.

3. A pole piece structure according to claim 1, characterized in that:

the stabilizing layer is an adhesive layer;

the material of the stabilizing layer is a hot-melt material, and the adhesive force of the hot-melt material is activated at a preset temperature.

4. A pole piece structure according to claim 3, characterized in that:

after the current collector is wound, the bonding force of the hot-melting material is activated in the hot-pressing state at the preset temperature, and adjacent lugs are bonded by the hot-melting material in a plurality of lugs arranged in the same direction.

5. A pole piece structure according to claim 2, characterized in that:

the current collector has a single-sided region and a double-sided region;

in the single-sided region, the active material layer is provided on the first side or the second side of the current collector; in the double-sided region, the active material layer is disposed on the first side and the second side of the current collector; wherein the plurality of tabs are disposed corresponding to the single-sided region and the double-sided region.

6. A pole piece structure according to any of claims 1-5, characterized in that:

the thickness of the stabilizing layer is 20-50um;

the height of the stabilizing layer is 1/3-5/6 of the height of the tab.

7. A pole piece structure according to claim 1, characterized in that:

the pole piece structure is a negative pole piece.

8. The utility model provides an electric core which characterized in that: a pole piece structure comprising any one of claims 1-7.

9. The cell of claim 8, wherein the cell is a wound roll core, the cell comprising:

a positive plate, a negative plate, and a separator between the positive plate and the negative plate;

the positive plate, the diaphragm and the negative plate are overlapped and are wound from the head to the tail to form the winding core.

10. A lithium ion battery, comprising:

a housing; and

the cell of claim 8 or 9, the cell being enclosed within the housing.