CN218385635U

CN218385635U - Electrode plate, battery cell and button cell

Info

Publication number: CN218385635U
Application number: CN202222484481.0U
Authority: CN
Inventors: 张瑞涛; 郭振冉
Original assignee: Zhuhai Cosmx Battery Co Ltd
Current assignee: Zhuhai Cosmx Battery Co Ltd
Priority date: 2022-09-20
Filing date: 2022-09-20
Publication date: 2023-01-24
Anticipated expiration: 2032-09-20

Abstract

The utility model provides an electrode slice, electric core and button cell, this electrode slice include the mass flow body, the mass flow body includes empty paper tinsel district, is located the active layer district outside the empty paper tinsel district, along the extending direction of the mass flow body, two the active layer district sets up respectively in two opposite sides of the empty paper tinsel district, at least one the active layer of active layer district keeps away from the end in empty paper tinsel district with the end of mass flow body flushes; the electrode plate comprises a spacer which is arranged in the empty foil area and covers the empty foil area in an orthographic projection manner. The full coverage of the empty foil area is realized through the isolating piece, so that the influence of burrs on the current collector on the battery cell is avoided, and the safety of the battery is improved.

Description

Electrode plate, battery cell and button cell

Technical Field

The utility model belongs to the technical field of the battery, concretely relates to electrode slice, electric core and button cell.

Background

The burr with larger size on the edge of the current collector can directly pierce through the diaphragm between the positive plate and the negative plate when winding, so that short circuit is caused, and the safety of the battery is affected. Especially, in the steel-shell button cell, the burr not only has the risk of impaling the diaphragm, still can extrude the pole piece, leads to the pole piece to have brokenly the risk of hole or fracture in the circulation inflation process, leads to the battery to open circuit, unable normal work.

SUMMERY OF THE UTILITY MODEL

The utility model provides an electrode slice, electric core and button cell, this electrode slice set up the separator on the empty paper tinsel district of mass flow body, realize the full coverability in empty paper tinsel district through the separator to avoid the influence of burr on the mass flow body to electric core, improve the security of battery.

One aspect of the utility model provides an electrode plate, including the mass flow body, the mass flow body includes empty paper tinsel district, is located the active layer district outside the empty paper tinsel district, along the extending direction of the mass flow body, two the active layer district is established separately in two opposite sides of the empty paper tinsel district, the active layer of at least one the active layer district is kept away from the tip of the empty paper tinsel district with the tip of the mass flow body is flushed; the electrode sheet comprises a spacer which is arranged in the empty foil area and covers the empty foil area in an orthographic projection mode.

In an embodiment of the present invention, in the length direction of the current collector, the end of the active layer region far from the empty foil region is flush with the end of the current collector.

In an embodiment of the present invention, in the length direction of the current collector, the separator includes a separator body and a separator extension portion, the separator extension portion extends toward the active layer region with an end portion of the separator body close to the active layer region as a start, and the extension portion is stacked on the active layer surface of the active layer region.

In one embodiment of the invention, the extension of the spacer extends to both active layer regions.

In an embodiment of the present invention, the size of the separator extension part is F, and F is greater than 0 and less than or equal to 4mm in the length direction of the current collector.

In an embodiment of the present invention, the separator has a size larger than that of the empty foil area in a width direction of the current collector.

In one embodiment of the present invention, the spacer has a thickness of 12 to 24 μm.

The utility model discloses an in an embodiment, the electrode slice still includes utmost point ear, and utmost point ear is located between the mass flow body surface in empty paper tinsel district and the separator in empty paper tinsel district.

The utility model discloses an among the embodiment, utmost point ear deviates from mass flow body one side and is equipped with the protective layer, and on the length direction of mass flow body, the separator covers the protective layer.

In an embodiment of the present invention, the separator covers a part of the protective layer in the width direction of the current collector.

In an embodiment of the present invention, the spacer is a glue layer.

The utility model discloses a second aspect improves a coiling type electricity core, including foretell electrode slice.

The utility model discloses an in the embodiment, anodal ear is located the outermost circle position of positive plate ending.

In an embodiment of the present invention, the electrode sheet includes a positive electrode sheet, a separator, and a negative electrode sheet, wherein the positive electrode sheet is the electrode sheet described above.

In an embodiment of the present invention, the negative electrode sheet includes a negative electrode active layer region and a third empty foil region and a fourth empty foil region respectively located at two ends of the negative electrode active layer region.

In an embodiment of the present invention, the negative electrode active layer region is larger than the size of the positive electrode sheet in the winding direction of the wound battery cell.

The utility model discloses an in the embodiment, the empty paper tinsel position of third is located the positive plate is close to the inboard of book heart, the empty paper tinsel position of fourth is located the outside of book heart is kept away from to the positive plate.

In an embodiment of the present invention, the separator on the positive plate covers a surface of the active layer region of the negative plate corresponding to the empty foil region of the positive plate.

The third aspect of the utility model provides an improve a button cell, including foretell electric core.

The utility model discloses an implement, following beneficial effect has at least:

the utility model provides an electrode slice, electric core and button cell are equipped with the separator in the empty paper tinsel district of mass flow body, utilize the separator to cover empty paper tinsel district at the orthographic projection in empty paper tinsel district, realize the full coverting in empty paper tinsel district through the separator to avoid mass flow body edge burr to the inside influence of electric core, improve the security of electric core.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings required for the description of the embodiments of the present invention will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic cross-sectional view of an electrode sheet according to an embodiment of the present invention;

fig. 2 is a schematic cross-sectional view of an electrode sheet according to another embodiment of the present invention;

fig. 3 is a schematic cross-sectional view of an electrode sheet according to another embodiment of the present invention;

fig. 4 is a schematic top perspective view of an electrode sheet according to an embodiment of the present invention;

fig. 5 is a schematic top perspective view of an electrode sheet according to another embodiment of the present invention;

fig. 6 is a first schematic cut-away cross-sectional view of an electrode sheet according to an embodiment of the present invention;

fig. 7 is a schematic cut-off cross-sectional view of an electrode sheet according to an embodiment of the present invention;

fig. 8 is a schematic top view of a cutting of an electrode sheet according to an embodiment of the present invention;

fig. 9 is a schematic cut-away cross-sectional view of an electrode sheet according to another embodiment of the present invention;

fig. 10 is a schematic top perspective cut-away view of an electrode sheet according to another embodiment of the present invention;

fig. 11 is a schematic cross-sectional view of a battery cell according to an embodiment of the present invention;

fig. 12 is a cycle performance test chart of a battery according to an embodiment of the present invention.

Description of reference numerals:

1-current collector;

11-empty foil areas;

103-a third empty foil area;

104-fourth empty foil region;

12-the active layer region;

121 — first active layer region;

122-second active layer region

1201-active material layer;

110-a spacer;

1101-a spacer body;

1102-spacer extensions;

1103 — a first body;

1104-second extension

2-pole ear;

22-positive tab;

23-negative tab;

21-a protective layer;

211 — a first protective layer;

212-a second protective layer;

4-positive plate;

5-negative pole piece;

6-a separator;

7-roll core ending glue.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

In the description of the present invention, unless otherwise explicitly specified or limited, the terms "disposed," "connected," and the like are to be construed broadly and may include, for example, a fixed connection, a detachable connection, and an integral connection; mechanical connection or electrical connection; the two elements may be connected directly or indirectly through an intermediate medium, or the two elements may be connected to each other. The above-described meaning of what is specifically intended in the present invention can be understood in specific instances by those of ordinary skill in the art. Furthermore, the terms "first", "second", "third", "fourth", and the like are used for descriptive purposes only, such as to distinguish between various components for clarity in explaining/explaining the technical solution, and are not to be construed as indicating or implying any number of technical features or order of significance.

In fig. 1 to 10, the X direction is the longitudinal direction of the current collector, the Y direction is the width direction of the current collector, and the Z direction is the thickness direction of the current collector.

Referring to fig. 1 to 5, the electrode plate provided by the present invention includes a current collector 1, the current collector 1 includes a hollow foil area 11, the hollow foil area 11 is located in the middle section of the current collector 1, and a spacer 110 is disposed on the hollow foil area 11; the orthogonal projection of the spacer 110 on the empty foil area 11 covers the empty foil area 11.

The utility model discloses in, can divide into active layer region 12 and empty paper tinsel district 11 with the mass flow body 1 according to whether set up active substance layer 1201. Active material layer 1201 is provided on active layer region 12, and the region of current collector 1 where active material layer 1201 is not provided is blank foil region 11.

The utility model discloses an empty paper tinsel district 11 sets up in the middle section of the mass flow body, and the middle section position indicates not can at the tip of mass flow body 1 length direction, includes first active layer district 121, empty paper tinsel district 11, second active layer district 122 in proper order promptly on the mass flow body 1 length direction.

The current collector 1 has two oppositely disposed surfaces, and the two surfaces of the current collector 1 refer to the largest and opposite surfaces on the current collector 1. Empty paper tinsel district 11 can be the single face setting or two-sided setting, promptly the utility model discloses an empty paper tinsel district 11 in the electrode slice can only expose a surface of mass flow body, perhaps exposes two surfaces of mass flow body simultaneously.

Further, when the empty foil area 11 is provided on a single side, a spacer 110 may be provided on the empty foil area 11; when the empty foil areas 11 are arranged on both sides, two spacers 110 are respectively arranged on the empty foil areas 11 on both sides.

The material of the spacer 110 is not limited in the present invention, and is preferably a non-conductive insulating material which is conventional in the art.

In the present invention, the spacer 110 covering the empty foil area 11 means that the size of the orthogonal projection of the spacer 110 in the empty foil area is equal to or larger than the size of the empty foil area 11. The orthographic projection of the separator 110 on the empty foil area refers to a projection formed by the separator 110 on the empty foil area under incident light perpendicular to a plane where the length of the current collector is located.

When the orthographic dimension of the spacer 110 in the empty foil region 11 is equal to the dimension of the empty foil region 11, the edge of the spacer 110 overlaps with the edge of the empty foil region 11. When the orthographic projection size of the spacer 110 in the empty foil region 11 is larger than the size of the empty foil region 11, the edge of the spacer 110 exceeds the edge of the empty foil region 11.

The utility model discloses in, be equipped with separator 110 on empty paper tinsel district 11, carry out the total coverage to empty paper tinsel district 11 through separator 110, make the burr at 1 edge of mass flow body can be covered by separator 110, can avoid burr on the empty paper tinsel district 11 to pierce through the diaphragm adjacent with empty paper tinsel district 11 in the electric core, avoid appearing positive plate and negative pole piece short circuit phenomenon to improve the security of electric core.

In general, the current collector 1 is provided with an active material layer 1201 in the active layer region 12. Active layer region 12 can be single face setting or two-sided setting, promptly the utility model discloses an active substance layer 1201 can only coat in the electrode slice on a surface of mass flow body, or the coating is two surfaces at mass flow body 1 simultaneously. It is preferable that the active material layers 1201 are respectively provided on both surfaces of the current collector.

In order to ensure the energy density of the battery and improve the capacity of the battery body, all regions of the current collector 1 outside the empty foil region 11 are active layer regions 12, i.e., the outer sides of the empty foil region 11 along the length direction of the current collector may be provided with active material layers 1201.

In the longitudinal direction of the current collector, the active material layers 1201 may be disposed in alignment with or not aligned with the upper and lower surfaces of the current collector. In order to secure the energy density of the battery, in a preferred embodiment, the active material layer 1201 is aligned on both upper and lower surfaces of the current collector.

The utility model discloses an in the implementation process, can adopt the technology of continuous coating, coating active substance layer 1201 on the active layer region 12 of electrode slice to get rid of the active substance layer through wasing in corresponding empty paper tinsel district 11 position, in order to expose the empty paper tinsel district 11 of mass flow body formation. The cleaning mode can be modes such as laser cleaning, mechanical cleaning or foamed adhesive cleaning, the utility model discloses do not limit the cleaning mode.

In the present invention, in the length direction of the current collector 1, the end of the active layer 1201 of the active layer region 12 away from the empty foil region 11 is flush with the end of the current collector 1. The number of the end parts of the active material layers 1201 far away from the empty foil area 11 is two, the end part of the first active layer area 121 far away from the empty foil area 11 can be flush with the end part of the current collector 1, the end part of the second active layer area 122 far away from the empty foil area 11 can be flush with the end part of the current collector 1, or simultaneously the end parts of the two active layer areas far away from the empty foil area can be flush with the end part of the current collector, in a preferred embodiment, at least the end part of the second active layer area 122 far away from the empty foil area is flush with the end part of the current collector 1.

This may be provided, in particular, as a practical matter, and in a preferred embodiment, both ends are preferably flush with the ends of the current collector 1.

In the above embodiment, the second active layer region 122 is the winding-starting end of the electrode sheet and the first active layer region 121 is the winding-ending end of the electrode sheet during the winding of the electrode sheet.

When the edge of the separator 110 exceeds the edge of the empty foil region 11, the separator 110 includes a separator body 1101 and a separator extension 1102 in the length direction of the current collector. Spacer extensions 1102 may be disposed outside of spacer body 1101. In the current collector length direction, the edge of the separator body 1101 overlaps the edge of the empty foil region 11, and the separator extension 1102 protrudes away from the edge of the separator body 1101 beyond the edge of the empty foil region.

In the longitudinal direction of the current collector, the separator extension 1102 extends toward the active layer region 12 with the end of the separator body 1101 close to the active layer region 12 as the starting end, so that the separator extension 1102 is stacked on the surface of the active layer 1201 of the active layer region 12.

In the length direction of the current collector, the separator body 1101 has two ends that are disposed opposite to each other, and the separator extension 1102 may be disposed at any one end of the separator body 1101, or may be disposed at both ends of the separator body 1101.

In order to avoid the active layer being covered by a large area and reduce the influence of the separator extension part 1102 on the battery cell, the dimension of the separator extension part 1102 in the length direction of the current collector is generally controlled to be F, and 0 < F ≦ 4mm. The utility model discloses do not limit to this, when isolator extension 1102 is greater than 4mm at the ascending size of length direction of mass flow body, isolator 110's size is great, causes great influence to the energy density of battery.

The dimensional parameters of the spacers 110 may be set with reference to a range of dimensional parameters of the empty foil regions 11. In one embodiment, the separator 110 may have a dimension in the length direction of the current collector 1 ranging from 10mm to 30mm, such as 10mm, 12mm, 14mm, 16mm, 18mm, 20mm, 22mm, 24mm, 26mm, 28mm, 30mm, or any two thereof. When the size of the separator 110 in the length direction of the current collector 1 is greater than 30mm, the size of the separator 110 is large, which has a large influence on the energy density of the battery.

Further, in the width direction of the current collector 1, the size of the separator 110 is equal to or larger than the size of the empty foil region 11. When the size of the spacer 110 is equal to the size of the empty foil area 11, the edge of the spacer 110 overlaps with the edge of the empty foil area 11. When the size of the separator 110 in the width direction of the current collector 1 is larger than the size of the empty foil region 11, the edge of the separator 110 exceeds the edge of the empty foil region 11. To further ensure complete coverage of the empty foil region 11 by the separator 110, it is preferable that the dimension of the separator 110 in the width direction of the current collector 1 is larger than the dimension of the empty foil region 11.

When the size of the separator 110 in the width direction of the current collector 1 is greater than the size of the empty foil region 11, the separator 110 includes a first body 1103 and a first extension 1104 in the width direction of the current collector 1, and the first extension 1104 is disposed outside the first body 1103. In the current collector width direction, the edge of the first body 1103 is flush with the edge of the empty foil area 11, and the edge of the first extension 1104 away from the first body 1103 exceeds the edge of the empty foil area. The first extension portion 1104 starts from an end portion of the first extension portion 1104 close to the empty foil region 11 and extends away from the empty foil region 11.

In order to avoid the active layer being covered by a large area and reduce the influence of the first extension portion 1104 on the battery cell, the size of the first extension portion 1104 in the length direction of the current collector is generally controlled to be G, and G is greater than 0 and less than or equal to 1.5mm.

In the width direction of the current collector, the first body 1103 has two ends disposed opposite to each other, and the first extending portion 1104 may be disposed at any end of the first body 1103, or may be disposed at both ends of the first body 1103 at the same time.

In order to further reduce the risk of short circuit between the positive electrode tab and the negative electrode tab and the risk of cutting off the electrode tab due to the burr pressing the electrode tab, the thickness of the separator 110 is generally controlled to be 12 μm to 24 μm, for example, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm, 22 μm, 24 μm or a range formed by any two of them. When the thickness of the separator 110 is greater than 24 μm, the thickness of the separator 110 is greater, which has a greater influence on the energy density of the battery.

The utility model discloses do not do the restriction to the size in empty foil district 11, in an embodiment, empty foil district 11 can be 6mm-24mm in the ascending size of length direction of mass flow body 1, for example can be 6mm, 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, 20mm, 22mm, 24mm or the scope that arbitrary two wherein constitute. When the size in the length direction of the empty foil area 11 is smaller than 6mm, the empty foil area is smaller, the exposed surface area of the current collector 1 is smaller, and the connection strength between the tab 2 and the current collector 1 is lower. When the dimension of the empty foil region 11 in the longitudinal direction is larger than 24mm, the empty foil region 11 is larger, which has a large influence on the energy density of the battery. The dimension of the empty foil region 11 in the width direction of the current collector 1 may be 3mm to 8.5mm.

The utility model discloses in, the electrode slice still includes utmost point ear 2, and utmost point ear 2 is used for carrying out electric connection with electrode slice and outside circuit. A tab 2 is normally provided on the aforementioned empty foil area 11. When the current collector 1 is connected with the tab 2, one surface of the empty foil area 11 is used for connecting with the tab 2.

In the above embodiment, the tab 2 is welded in the area of the empty foil area 11, for example, the tab 2 and the current collector 1 can be welded together by ultrasonic welding, and the tab 2 and the current collector 1 can also be welded together by laser welding, which is not limited herein.

In the empty foil area 11 that sets up utmost point ear 2, utmost point ear 2 is located between the mass flow body surface in empty foil area 11 and the separator 110 in empty foil area, and separator 110 not only covers empty foil area 11, can also cover utmost point ear 2 that is located empty foil area 11, and from this, separator 110 can also avoid the negative effects that the burr brought on the solder joint of utmost point ear 2.

The tab 2 has a tab body and a tab extension, and the edge of the tab body is located in the empty foil area, so that the tab body is located between the current collector surface of the empty foil area 11 and the separator 110 of the empty foil area. The tab extension exceeds the edge of the empty foil area 11 in the length direction of the current collector with the edge far away from the tab body, so that when the electrode plate is applied to a battery, the tab of the battery for an external electric device is formed.

In order not to influence the connection strength of the tab 2, the tab 2 may be further provided with a protective layer 21, one side of the tab 2 departing from the current collector 1 may be covered with the protective layer 21, the protective layer 21 plays a role in fixing the tab, and in addition, the protective layer 21 may prevent burrs on the tab from piercing a diaphragm adjacent to the empty foil area 11 in the battery core. Wherein the protective layer 21 covers only the tab 2.

To further protect the tab, protective layers, i.e., a first protective layer 211 and a second protective layer 212, are generally disposed on both surfaces of the empty foil area to which the tab is welded.

Therefore, the tab 2 is arranged in the empty foil area 11, the protective layer 21 covers the tab 2, and the separator 110 covers the empty foil area 11, so that under the dual protection of the protective layer 21 and the separator 110, the risk that burrs on the empty foil area 11 and the tab 2 pierce the diaphragm can be further reduced.

The utility model discloses do not limit to the protective layer, protective layer 21 includes but not only is limited to utmost point ear protection and glues. Note that the protective layer 21 is used to protect the tab 2, and the separator 110 is used to cover the empty foil region 11, but the separator 110 of the present invention is not the protective layer 21.

The material of the spacer 110 is not limited in the present invention, and may be a non-conductive insulating material that is conventional in the art. In a preferred embodiment, the spacer 110 is a glue layer.

In the present invention, the electrode sheet is a negative electrode sheet or a positive electrode sheet, and may be specifically determined according to the specific selection of the current collector 1 and the material of each active material layer 1201. For example, when the current collector 1 is an aluminum foil and the material of the active material layer 1201 is a ternary material or a positive active material such as lithium iron phosphate, the electrode sheet is a positive electrode sheet; when the current collector 1 is a copper foil and the material of the active material layer 1201 is a negative active material such as graphite and silicon base, the electrode sheet is a negative electrode sheet.

The utility model discloses do not limit to the preparation method of electrode slice, can adopt the conventional film-making method in this field to go on. Referring to fig. 6 to 10, the electrode sheet assembly is usually cut into electrode sheets with standard widths by a cutting device. The pole piece group is a structure formed by connecting a plurality of electrode pieces to be cut end to end. And every two electrode plates to be cut are connected through a hollow foil area.

In the electrode plate set, a current collector 1 is divided into an active layer region 12 and a hollow foil region 11, active substance layers 1201 are arranged on two surfaces of the active layer region 12, the active substance layers 1201 on the two surfaces are coated in an aligned mode, and the size of the current collector in the length direction meets A = C; the empty foil areas 11 are arranged in a double-sided alignment mode, and the size of the empty foil areas 11 on the two sides in the length direction of the current collector meets B = D.

The utility model discloses in, set up isolator 110 before cutting the electrode slice group, promptly before cutting the electrode slice group, set up isolator 110 on every relevant position of treating the electrode slice that cuts, the burr that collects the production of current 1's edge can be covered by isolator 110, then rethread cutting equipment cuts the electrode slice group. The sheet making mode greatly shortens the sheet making time, improves the making efficiency and can ensure that the empty foil area 11 is completely covered by the partition 110.

Specifically, the electrode sheet group is provided with at least one cutting line a distributed in the length direction of the current collector, so that the electrode sheet group is cut along the cutting line a to form the electrode sheet. Further, in order to obtain the electrode sheet, a cutting line a may be provided on the active layer region 12, specifically, the active material layer 1201, and the electrode sheet may be obtained by cutting along the cutting line a of the separator 110 on the electrode sheet group.

In one embodiment, as shown in fig. 7 and 8, the electrode sheet set includes a first electrode sheet S1 to be cut and a second electrode sheet S2 to be cut along the length direction of the current collector, and the electrode sheet set has a cutting line a on the active material layer 1201, and the electrode sheet set is cut along the cutting line a to form the electrode sheet shown in fig. 2. The position of the cutting line a is located in the active material layer 1201 of the second electrode sheet S2 to be cut, and the shortest distance between the cutting line a and the empty foil area is E, where E =2 mm-30mm, and E is greater than F.

In order to ensure that the end of the active layer region, which is far away from the empty foil region, is flush with the end of the current collector, in a preferred embodiment, the cutting line a is parallel to the width direction of the current collector 1, and the cutting direction b of the cutting line a is parallel to the thickness direction of the current collector 1.

In another embodiment, as shown in fig. 9 and 10, the electrode sheet assembly may be divided into a first electrode sheet S1 to be cut, a second electrode sheet S2 to be cut, and a third electrode sheet S3 to be cut along the length direction of the current collector 1, the electrode sheet assembly has a first cutting line a1 and a second cutting line a2 along the length direction of the current collector, the active material layers 1201 on the active layer region of the second electrode sheet S1 to be cut and the third electrode sheet S3 to be cut are respectively located, and the electrode sheet assembly is cut along the first cutting line a1 and the second cutting line a2 to form the electrode sheet shown in fig. 3.

The first cutting line a1 is located on the active material layer 1201 of the second electrode sheet S2 to be cut and is spaced from the empty foil region (the empty foil region between S1 and S2) by a distance E, and the second cutting line a2 is located on the active material layer 1201 of the third electrode sheet S3 to be cut and is spaced from the empty foil region (the empty foil region between S2 and S3) by a distance E, where E =2mm to 30mm, and E is greater than F.

In order to ensure that the end of the active layer 1201 of the active layer region 12 away from the empty foil region 11 is flush with the end of the empty foil region 11, in a preferred embodiment, the first cutting line a1 and the second cutting line a2 are parallel to the width direction of the current collector 1, and the cutting directions b1, b2 are parallel to the thickness direction of the current collector 1.

The utility model provides an electric core, this electric core are including a plurality of positive plate and a plurality of negative pole piece that range upon range of setting in proper order, and positive plate and/or negative pole piece are aforementioned electrode slice. And a diaphragm is arranged between every two adjacent positive plates and negative plates and is used for preventing the short circuit of the battery caused by the contact of the polar plates with opposite polarities.

The battery cell can be a winding battery cell or a laminated battery cell. When the cell is a laminated cell, the positive electrode plate and/or the negative electrode plate may be the electrode plates. Preferably, the number of the empty foil areas on the positive plate and the negative plate is one. The empty foil area of the positive plate and the empty foil area of the negative plate can be arranged opposite to each other or not.

When the battery cell is a winding battery cell, the positive electrode plate or the negative electrode plate may be the aforementioned electrode plate, and in a preferred embodiment, the positive electrode plate is the aforementioned electrode plate, please refer to fig. 11. When the electrode sheet is wound into the battery cell, the winding start end of the battery cell is the head of the electrode sheet, and the winding end of the battery cell is the tail of the electrode sheet.

In one embodiment, as shown in fig. 11, the head of positive electrode sheet 4 is the second active layer region 122, the tail of positive electrode sheet 4 is the first active layer region 121, separator 110 is disposed on the empty foil region 11 of the positive electrode sheet, and positive tab 22 is located between the current collector surface of the empty foil region 11 and separator 110. The positive electrode active material layers are provided on the first active layer region 121 and the second active layer region 122 located outside the empty foil region, and the end portions of the positive electrode active material layers of the head and tail portions of the positive electrode sheet, which are away from the empty foil region 11, are flush with the end portion of the current collector 1. The shortest distance between the empty foil area 11 of the positive plate and the end part of the current collector of the positive plate in the length direction is 2 mm-30mm, so that the positive tab 22 can be located at the outer ring of the battery cell when the battery cell is in a winding state.

The end, far away from the empty foil district 11, of the positive active material layer of the head and the tail of the positive plate 4 is flush with the end of the current collector, the partition 110 covers the empty foil district 11 in the orthographic projection of the empty foil district 11, burrs at the edge of the current collector of the positive plate 4 can be covered by the partition 110 and the active layer, the burrs on the empty foil district of the positive plate can be prevented from piercing through the diaphragm 6 adjacent to the empty foil district in the battery core, and the short circuit phenomenon of the positive plate and the negative plate is prevented from occurring.

The active layer region can be a single-sided arrangement or a double-sided arrangement. When disposed on both sides, the active material layer may be applied with or without alignment of the head portion, or with or without alignment of the tail portion. In order to increase the energy density, it is preferable that the active layer regions of the positive electrode sheet 4 are both arranged in a double-sided alignment.

The empty foil regions may be single-sided or double-sided. In order to increase the energy density, the foil areas are preferably double-sided, and the foil areas on each side are provided with an insulating member.

In the winding electric core, a third empty foil area 103 is arranged at the head of the negative electrode sheet 5, and a fourth empty foil area 104 is arranged at the tail of the negative electrode sheet. In order to protect the short circuit risk caused by lithium dendrite at the edge of the active layer region of the electrode plate, the third and fourth

empty foil regions

103 and 104 of the negative electrode plate are preferably arranged on two sides, i.e. no active material layer is arranged on the two sides.

The negative tab 23 is located on the collector surface of the fourth empty foil area 104, and the surface of the negative tab 23 may be covered with a protective layer.

The negative electrode active material layer is provided on the negative electrode active layer region outside the third and fourth empty foil regions. In order to inhibit the lithium precipitation phenomenon, the size of the active material layer of the negative electrode sheet is generally larger than that of the active material layer of the positive electrode sheet, that is, the edge of the active area of the negative electrode sheet exceeds the edge of the active area of the positive electrode sheet, otherwise the lithium precipitation phenomenon occurs on the edge of the negative electrode sheet in the battery cell, and the safety performance of the battery is reduced. In one embodiment, the active material layer of the negative electrode sheet covers the active material layer of the negative electrode sheet facing the positive electrode sheet.

Further, in the winding cell, the electrode sheet at the innermost circle and the outermost circle of the winding cell is the negative electrode sheet 5. In order to realize that the electrode plate at the outermost circle of the wound battery core is the negative electrode plate 5, in the wound battery core, the tail part of the negative electrode plate 5 is positioned at the outer side of the tail part of the positive electrode plate 4, which is far away from the winding core.

In order to improve the utilization rate of the material, the surface of the current collector of the negative electrode sheet 5 positioned at the outermost circle and facing away from the positive electrode sheet 4 may not be coated with an active material layer. A core ending adhesive 7 is generally used for coating the cell.

The utility model provides a button cell, this button cell include foretell electric core. The utility model discloses well no restriction is done to button cell's kind, for example can be cylindrical battery, square aluminum hull battery. Utilize separator 110 to realize the full coverage in empty paper tinsel district 11, can avoid the marginal burr on empty paper tinsel district 11 to pierce through the diaphragm 6 adjacent with empty paper tinsel district 11 in the electric core, avoid appearing positive plate and negative pole piece short circuit phenomenon, reduce the burr in the electric core to the extruded risk of adjacent pole piece, improve the security and the cycling performance of battery.

The present invention will be further described with reference to the following specific examples.

Example 1

(1) As shown in fig. 7, before cutting, a tab 2, tab glue (protective layer) 21/22 and a separator 110 are sequentially arranged on an empty foil area 11 of a positive electrode plate group; the positive electrode plate group is divided into a first electrode plate S1 to be cut and a second electrode plate S2 to be cut, and a tab glue (protective layer) 21 is positioned between a tab 2 and the separator 110;

(2) As shown in fig. 7 and 8, cutting the electrode sheet set in step (1) along a cutting line a, wherein the cutting line a is located on the second electrode sheet S2 to be cut, is located on the active material layer 1201 of the second electrode sheet S2 to be cut, and is cut at a position with a shortest distance E =2 mm-30mm from the empty foil area; obtaining a first electrode sheet to be cut after cutting, as shown in fig. 2; the cutting line a is parallel to the width direction of the current collector, and the cutting direction of the cutting line is parallel to the thickness direction of the current collector;

(3) And (3) winding the first electrode slice to be cut after cutting in the step (2) and the corresponding negative electrode to obtain a battery cell, and packaging the battery cell to form a polymer button type lithium ion battery with the diameter of 10mm, the height of 5.4mm and the single battery capacity of 42mAh, and recording as a battery sample C2.

Example 2

(1) As shown in fig. 9, before cutting, a tab 2, tab glue (protective layer) 21/22 and a separator 111/112 are sequentially arranged on each empty foil area of the positive electrode plate group; the positive electrode plate component comprises a first electrode plate to be cut S1, a second electrode plate to be cut S2 and a third electrode plate to be cut S3; the tab glue is positioned between the tab and the separator;

(2) As shown in fig. 9 and 10, the pole piece group in step (1) is cut along a first cutting line a1 and a second cutting line a2, the cutting lines are located on the separator, the first cutting line a1 is located at the shortest distance E =2mm to 30mm from the active material layer 1201 of the second electrode piece to be cut S2 and the empty foil area, and the second cutting line a2 is located at the shortest distance E =2mm to 30mm from the active material layer 1201 of the second electrode piece to be cut S2 and the empty foil area; obtaining a second electrode plate to be cut after cutting, as shown in fig. 3; the first cutting line a1 and the second cutting line a2 are parallel to the width direction of the current collector, and the cutting direction is parallel to the thickness direction of the current collector;

(3) And (3) winding the second electrode plate to be cut after cutting in the step (2) and the corresponding negative electrode to obtain a battery cell, and packaging the battery cell to form a polymer button type lithium ion battery with the diameter of 10mm, the height of 5.4mm and the single battery capacity of 42mAh, and recording as a battery sample C3.

Comparative example 1

Compared with the embodiment 1, in the step (1), the tabs and the tab glue are sequentially arranged on the empty foil area of the positive electrode plate group, and no separator is arranged; and (3) in the step (2), the cutting line is positioned on the empty foil area, and the cell sample C1 is recorded when other conditions are unchanged.

The battery samples C1, C2, and C3 were subjected to a voltage drop test after being stored at 100% soc (full charge) for 30 days in an environment of 25℃, and a cycle test in an environment of 45℃, and the results are shown in table 1 and fig. 12.

TABLE 1 Battery Performance test Table

Group of	Pressure drop/V
		C1	0.045V
C2	0.028V
		C3	0.023V

As can be seen from table 1, the cell of comparative example 1 has a relatively large pressure drop, and the cells of examples 1 and 2 have relatively small pressure drops. As can be seen from fig. 12, the increase in the number of cycles of the battery of comparative example 1 resulted in a large capacity fade, and the cycle performance was poor. The cycling performance of example 1 and example 2 was relatively good.

It should be noted that the numerical values and numerical ranges related to the embodiments of the present invention are approximate values, and there may be a certain range of errors due to the manufacturing process, and the error can be considered to be ignored by those skilled in the art.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention.

The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiment. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The electrode plate is characterized by comprising a current collector, wherein the current collector comprises a hollow foil area and an active layer area positioned outside the hollow foil area, the two active layer areas are respectively arranged on two opposite sides of the hollow foil area along the extension direction of the current collector, and the end part, away from the hollow foil area, of the active layer of at least one active layer area is flush with the end part of the current collector; the electrode plate comprises a spacer which is arranged in the empty foil area and covers the empty foil area in an orthographic projection manner.

2. The electrode sheet according to claim 1, wherein an end of the active layer region, which is away from the empty foil region, is flush with an end of the current collector in a length direction of the current collector.

3. The electrode sheet according to claim 1 or 2, wherein the separator includes a separator body and a separator extension extending toward the active layer region from an end of the separator body close to the active layer region in a longitudinal direction of the current collector, and the extension is stacked on the active layer surface of the active layer region.

4. The electrode sheet of claim 3, wherein the extension of the separator extends to both of the active layer regions.

5. The electrode sheet as defined in claim 3, wherein the separator extension has a dimension F,0 < F ≦ 4mm in the length direction of the current collector; and/or the presence of a gas in the gas,

the size of the separator is larger than that of the empty foil area in the width direction of the current collector; and/or the presence of a gas in the gas,

the thickness of the separator is 12-24 μm.

6. The electrode sheet according to claim 1, further comprising a tab, wherein the tab is located between the current collector surface of the empty foil region and the separator of the empty foil region.

7. The electrode sheet according to claim 6, wherein a protective layer is arranged on one side of the tab, which faces away from the current collector, and the separator covers the protective layer in the length direction of the current collector.

8. The electrode sheet according to claim 7, wherein the separator covers a portion of the protective layer in a width direction of the current collector.

9. The electrode sheet of claim 1, wherein the separator is a glue layer.

10. A wound electrical core comprising the electrode sheet of any one of claims 1 to 9.

11. The wound cell of claim 10, wherein the positive tab is positioned at an outermost turn of the positive tab ending in the wound cell.

12. The wound electrical core according to claim 11, comprising a positive electrode sheet, a separator, and a negative electrode sheet, wherein the positive electrode sheet is the electrode sheet according to any one of claims 1 to 9,

the negative plate comprises a negative active layer region, and a third empty foil region and a fourth empty foil region which are respectively positioned at two ends of the negative active layer region.

13. The wound cell of claim 12, wherein the negative active layer region is larger than the positive plate in the winding direction of the wound cell.

14. The wound cell of claim 13, wherein the third empty foil region is located on the inner side of the positive electrode sheet close to the winding core, and the fourth empty foil region is located on the outer side of the positive electrode sheet far from the winding core.

15. The wound cell of claim 13 or 14, wherein the separator on the positive electrode sheet covers a surface of the active layer region of the negative electrode sheet corresponding to the empty foil region of the positive electrode sheet.

16. A button cell comprising a wound cell according to any of claims 10-15.