CN217507572U

CN217507572U - Diaphragm for button cell and button cell

Info

Publication number: CN217507572U
Application number: CN202221389173.3U
Authority: CN
Inventors: 王晓飞; 林伟林; 施继琴
Original assignee: Fujian Nanping Nanfu Battery Co Ltd
Current assignee: Fujian Nanping Nanfu Battery Co Ltd
Priority date: 2022-06-06
Filing date: 2022-06-06
Publication date: 2022-09-27
Anticipated expiration: 2032-06-06

Abstract

The utility model provides a diaphragm and button cell for button cell, the diaphragm is a thin slice structure, and it outwards divide into diaphragm central part and annular diaphragm peripheral part in proper order from the center, the size of diaphragm central part in order to incite somebody to action when the coaxial button cell shell of packing into of diaphragm in the outer border of diaphragm central part can with the interior perisporium of button cell shell laminates for the limit each other the outer border of diaphragm peripheral part is followed its circumference evenly spaced apart and is equipped with two at least breachs, thereby the breach inwardly extends to thereby the outer border department of diaphragm central part will diaphragm peripheral part is cut apart into at least two sections. The diaphragm of the utility model can be better attached to the inner peripheral wall of the button cell shell, and the internal micro short circuit caused by the falling of the micro anode powder is avoided when the anode plate is assembled; or internal short caused by partial contact of the positive and negative electrodes.

Description

Diaphragm for button cell and button cell

Technical Field

The utility model relates to a battery structure field especially relates to a diaphragm for button cell.

Background

The button lithium-manganese battery is a battery which takes metal lithium as a negative active material and manganese dioxide as a positive active material and is packaged by using a button steel shell, and is one of the most mature series of the current lithium batteries. The lithium ion battery has the advantages of high working voltage, lower manufacturing cost, wide use temperature range, long storage life and the like, and becomes one of the most widely applied commercial lithium batteries. The conventional lithium-manganese button cell structure comprises a positive plate shell, a negative plate cover, a positive plate (a sheet structure formed by pressing manganese dioxide slurry), a negative plate (namely a lithium plate, also called as a negative lithium plate) and a diaphragm, wherein the positive plate shell and the negative plate cover are both in a cylindrical shape with only one open end, the positive plate shell and the negative plate cover are oppositely buckled to form a shell (namely a button steel shell) of the button cell, and a sealing ring is embedded between the positive plate shell and the negative plate cover; the positive plate is attached to the inner side of the bottom surface of the positive shell, the diaphragm is laid on the positive plate, and the negative plate is stacked on the diaphragm and is in contact with the bottom surface of the negative cover. To prevent the positive electrode sheet from swelling outward, the positive electrode sheet is also usually placed in a cylindrical positive electrode cover.

The diaphragm for the existing lithium-manganese button cell is a circular paper sheet in a flat-laid state. In the assembly process of the lithium manganese button cell, the positive plate needs to be completely isolated from the negative plate to prevent short circuit, so the design diameter of the diaphragm is often larger than the inner diameter of the negative shell. The diameter of the diaphragm is larger than that of the negative electrode shell, which means that the diaphragm at the peripheral part can be attached to the inner peripheral wall of the negative electrode shell, but the diaphragm is difficult to perfectly attach to the side wall of the negative electrode shell, and a certain gap exists. Due to the existence of the gaps, when the anode is assembled, the micro particles falling off from the anode contact the cathode, so that local micro short circuit is caused, and the discharge performance of the battery is influenced; moreover, when the positive electrode is assembled, the deformation of the diaphragm caused by pressure can also cause local contact between the positive electrode and the negative electrode, so that the battery is short and scrapped.

SUMMERY OF THE UTILITY MODEL

One of the purposes of the utility model is to provide a diaphragm for button cell, which can be better attached to the inner peripheral wall of the battery shell, and avoid the internal micro short circuit caused by the falling of micro anode powder when assembling the anode plate; or an internal short caused by local contact of the positive and negative electrodes.

A diaphragm for a button cell is of a thin sheet structure and is sequentially divided into a diaphragm center part and an annular diaphragm outer peripheral part from the center to the outside, the size of the diaphragm center part is limited to the extent that the outer edge of the diaphragm center part can be mutually attached to the inner peripheral wall of a button cell shell when the diaphragm is coaxially installed in the button cell shell, at least two notches are uniformly arranged on the outer edge of the diaphragm outer peripheral part at intervals along the circumferential direction of the diaphragm outer peripheral part, and the notches extend inwards to the outer edge of the diaphragm center part so as to divide the diaphragm outer peripheral part into at least two sections.

The notch design of the utility model can ensure that the outer peripheral part of the diaphragm can be better attached to the inner peripheral wall of the battery shell when the diaphragm is arranged in the button battery shell, and the internal micro short circuit caused by the falling of the micro powder of the positive plate when the positive plate is arranged is avoided; meanwhile, internal short circuit caused by local contact of the positive plate and the negative lithium plate is avoided.

When the battery is assembled, the diaphragm is coaxially contained in the button battery shell, the peripheral part of the diaphragm is bent towards the positive electrode relative to the central part of the diaphragm, and the outer edge of the central part of the diaphragm and the outer peripheral surface of the peripheral part of the diaphragm are mutually attached to the inner peripheral wall of the button battery shell.

In a specific implementation process, the button cell shell comprises a negative cover and a positive cover which are arranged oppositely, the positive cover and the negative cover are both in a cylindrical shape with only one end open, the positive cover and the negative cover are buckled oppositely, and a sealing ring is embedded between the positive cover and the negative cover for sealing; and a positive plate, a diaphragm and a negative lithium plate are sequentially superposed in the button cell shell along the axial direction from the positive cover to the negative cover, and the diaphragm completely separates the positive plate from the negative lithium plate.

Preferably, the number of the notches is 2-18, preferably 4-12, and at the moment, the attaching effect of the diaphragm and the inner peripheral wall of the battery shell is optimal.

The surface of each notch is composed of a plurality of sections of continuous curved surfaces, or a plurality of sections of continuous planes, or a combination of the curved surfaces and the planes. Further, the notch is preferably an isosceles triangle or an isosceles triangle with two arc-shaped waists, and at this time, the vertex angle of the notch is preferably toward the central part of the diaphragm. Preferably, the angle of the top angle of the notch is between 10 and 120 degrees, the smaller the angle of the top angle is, the easier the punching process is, and in order to simplify the punching process of the diaphragm, the angle of the top angle of the notch is preferably between 30 and 90 degrees.

The second objective of the present invention is to provide a button cell, which includes the above-mentioned diaphragm for button cell.

Drawings

Fig. 1 is a schematic top view of a separator for a button cell of example 1 in a flat state;

fig. 2 is a schematic longitudinal sectional structure of a button cell according to any one of embodiments 1 to 3;

fig. 3 is a schematic view of the shape of a notch in a plan view from a flat state of a separator for a button cell of example 2;

fig. 4 is a schematic view of the shape of a notch in a plan view from a flat state of the separator for a button cell of example 3;

in each of fig. 1, 3, and 4, the dotted lines represent the boundary between the diaphragm outer peripheral portion and the diaphragm central portion.

Detailed Description

The following detailed description of the button cell of the present invention is made with reference to the accompanying drawings:

example 1

With reference to fig. 1 and 2, a diaphragm 30 for a button cell is a thin sheet structure, which is divided into a diaphragm center 301 and an annular diaphragm outer periphery 302 from the center to the outside in sequence, the size of the diaphragm center 301 is limited to that the outer edge of the diaphragm center 301 can be attached to the inner periphery wall of a button cell casing 10 when the diaphragm 30 is coaxially installed in the button cell casing 10, 8 notches 300 are uniformly spaced along the circumference of the outer edge of the diaphragm outer periphery 302, and the notches 300 extend inwards to the outer edge of the diaphragm center 301 to divide the diaphragm outer periphery 302 into 8 segments;

the surface of each notch 300 is composed of two continuous planes 3001, and the notches 300 are isosceles triangles.

As shown in fig. 2, the separators for button cells of example 1 were assembled to form the button cells of example 1 (lithium manganese button cells).

Example 2

As shown in fig. 3, the separator for a button cell of example 2 is different from that of example 1 in that: the surface of each notch 300 is composed of two continuous curved surfaces 3002, and the notches 300 are isosceles triangles with two arc-shaped waists.

As shown in fig. 2, the button cell of example 2 (lithium manganese button cell) was assembled using the button cell separator of example 2.

Example 3

As shown in fig. 4, the separator for a button cell of example 3 is different from that of example 1 in that: the surface of each notch 300 is composed of a combination of a flat surface 3003 and a curved surface 3004, and the notch is U-shaped.

As shown in fig. 2, the button cell of example 3 (lithium manganese button cell) was assembled using the button cell separator of example 3.

The notch 300 design of the separator in each of embodiments 1 to 3 can ensure that each segment of the outer periphery 302 of the separator can be better attached to the inner peripheral wall of the battery shell 10 when the separator 30 is installed in the button battery shell 10, so as to prevent internal micro short circuit caused by the falling of fine powder of the positive plate 20 when the positive plate 20 is installed; meanwhile, internal short circuit caused by local contact of the positive electrode tab 20 and the negative electrode lithium tab 40 is also avoided.

Of course, the utility model discloses a quantity of breach 300 is not limited to 8, and it can to satisfy 2 at least requirements, in order to simplify the diaphragm punching technology, the quantity control of breach 300 is in 2 ~ 18, preferably 4 ~ 12, and at this moment, the laminating effect of diaphragm 30 and battery case 10's internal perisporium is best. The utility model discloses a diaphragm and button cell for button cell are not limited to lithium manganese button cell, and it is applicable to the button cell of any system.

In fig. 1 to 4, a boundary between the diaphragm outer peripheral portion 302 and the diaphragm central portion 301 is a virtual line, and does not exist in any actual state.

As shown in fig. 2, when the battery is assembled, the separator 30 is coaxially housed in the button cell case 10, the separator outer circumferential portion 302 is bent toward the positive electrode side with respect to the separator center portion 301, and both the outer edge of the separator center portion 301 and the outer circumferential surface of the separator outer circumferential portion 302 are bonded to the inner circumferential wall of the button cell case 10.

In a specific implementation process, as shown in fig. 2, the button cell housing 10 includes a negative cover 11 and a positive cover 12 that are oppositely disposed, the positive cover 12 and the negative cover 11 are both in a cylindrical shape with only one open end, the positive cover 12 and the negative cover 11 are oppositely fastened, and a sealing ring 13 is embedded between the positive cover 12 and the negative cover 11 for sealing; in the button cell case 10, a positive electrode sheet 20, the above-mentioned diaphragm 30 for button cell and a negative electrode lithium sheet 40 are stacked in order along the axial direction from the positive electrode cover 12 to the negative electrode cover 11, and the positive electrode sheet 20 and the negative electrode lithium sheet 40 are completely separated by the diaphragm 30.

As shown in fig. 1 and 3, the notches 300 are preferably in the shape of an isosceles triangle or an isosceles triangle with two arc-shaped sides. At this time, as shown in fig. 1 and 3, the apex angle of the notch 300 is preferably directed toward the diaphragm center 301. Preferably, the angle α of the vertex angle of the notch 300 is between 10 ° and 120 °, and since the notch 300 is formed by the diaphragm punching process, the smaller the angle of the vertex angle, the easier the punching process is to be implemented, and in order to simplify the diaphragm punching process, the angle α of the vertex angle of the notch 300 is preferably between 30 ° and 90 °.

The diaphragm 30 of the present invention may be any one of a polypropylene diaphragm, a glass fiber diaphragm, a polyethylene diaphragm, and an ethylene-propylene copolymer diaphragm.

In addition, in order to prevent the positive electrode sheet from swelling outward, the positive electrode sheet 20 is usually placed in a cylindrical positive electrode cover (as shown in fig. 2).

The utility model discloses right the utility model belongs to the technical field of the ordinary skilled person, do not deviating from the utility model discloses under the prerequisite of design, can also make a plurality of simple deductions or replacement, all should regard as belonging to the utility model discloses a protection scope.

Claims

1. A separator for a button cell, which has a sheet structure and is divided into a separator center portion and an annular separator outer peripheral portion in this order from the center to the outside, wherein the size of the separator center portion is limited so that the outer edge of the separator center portion can be fitted to the inner peripheral wall of a button cell case when the separator is coaxially mounted in the button cell case, characterized in that: at least two notches are uniformly arranged on the outer edge of the diaphragm peripheral part at intervals along the circumferential direction of the diaphragm peripheral part, and the notches extend inwards to the outer edge of the diaphragm central part so as to divide the diaphragm peripheral part into at least two sections.

2. The separator for button cell according to claim 1, wherein: when the battery is assembled, the diaphragm is coaxially contained in the button battery shell, the peripheral part of the diaphragm is bent towards the positive electrode relative to the central part of the diaphragm, and the outer edge of the central part of the diaphragm and the outer peripheral surface of the peripheral part of the diaphragm are mutually attached to the inner peripheral wall of the button battery shell.

3. The separator for button cell according to claim 1, wherein: the number of the notches is 4-12.

4. The separator for button cells according to claim 1, wherein: the inner surface of each notch is composed of a plurality of sections of continuous curved surfaces, or a plurality of sections of continuous planes, or a combination of the curved surfaces and the planes.

5. The separator for button cells according to claim 1, wherein: the gap is an isosceles triangle or an isosceles triangle with two arc waists.

6. The separator for button cell according to claim 5, wherein: the apex angle of the notch faces the center of the diaphragm.

7. The separator for button cell according to claim 6, wherein: the angle of the top angle of the notch is between 30 and 90 degrees.

8. The separator for button cell according to claim 2, wherein: the button cell shell comprises a negative cover and a positive cover which are oppositely arranged, wherein the positive cover and the negative cover are both in a cylindrical shape with only one open end, the positive cover and the negative cover are oppositely buckled, and a sealing ring is embedded between the positive cover and the negative cover for sealing; and a positive plate, the diaphragm and a negative lithium plate are sequentially stacked in the button cell shell along the axial direction from the positive cover to the negative cover, and the positive plate and the negative lithium plate are completely separated by the diaphragm.

9. A button cell comprising the separator for a button cell according to any one of claims 1 to 8.