CN218414935U

CN218414935U - Diaphragm for improving performance of cylindrical lithium ion battery

Info

Publication number: CN218414935U
Application number: CN202222188075.XU
Authority: CN
Inventors: 许飞; 尚海东; 张向举; 赵永锋; 韩广欣; 马红涛; 罗传军; 杲召芒; 刘继东; 杨威振; 赵盼盼
Original assignee: Guangxi Ningfu New Energy Technology Co ltd
Current assignee: Guangxi Ningfu New Energy Technology Co ltd
Priority date: 2022-08-19
Filing date: 2022-08-19
Publication date: 2023-01-31
Anticipated expiration: 2032-08-19

Abstract

The utility model discloses a diaphragm for improving the performance of a cylindrical lithium ion battery, wherein the thickness of the diaphragm is gradually reduced from the starting end to the tail end or the thickness of the diaphragm is sequentially reduced from the starting end to uniform thickness and reaches the tail end after keeping a section of length; the diaphragm is wound on the battery cell from the starting end; the total length of the diaphragm is L, the starting end is sequentially reduced to the length L1 with uniform thickness, and the length L1 is one half of L; the utility model can improve the cycle performance of the battery, reduce the risk of lithium precipitation and improve the safety; when the length of the membrane is wound to be half of the total membrane length, the thickness of the membrane is kept constant, the membrane at the rear section is ensured to maintain certain tensile strength, and the reliability of electronic insulation is ensured.

Description

Diaphragm for improving performance of cylindrical lithium ion battery

Technical Field

The utility model relates to a lithium ion battery field specifically is a promote diaphragm of cylinder lithium ion battery performance.

Background

With the gradual popularization of electric vehicles, the development of the core component power lithium ion battery industry is rapid, and the improvement of the cycle life of the lithium ion battery is particularly important; a winding process is carried out in the manufacturing process of the cylindrical lithium ion battery: the diaphragm, the positive plate and the negative plate are wound into a columnar structure through a winding machine, the diaphragm is positioned between the positive plate and the negative plate, and the positive plate and the negative plate are separated to achieve an electronic insulation effect. The winding structure is adopted, the internal stress distribution of the battery is that the front section is the largest, and the rear section is gradually reduced; when the battery is charged, after lithium ions are inserted into the negative plate, the negative plate is further expanded, and the diaphragm is further compressed, so that the positive and negative plates at the front winding section are worst in the infiltration effect of the electrolyte, lithium is easy to separate at the position, the safety of the battery is reduced, and the cycle performance of the battery is also seriously reduced.

Disclosure of Invention

The utility model aims at providing a promote diaphragm of cylinder lithium ion battery performance to the problem of diaphragm initiating terminal compressed attenuation among the solution prior art.

In order to realize the purpose, the technical scheme of the utility model is that:

the thickness of the diaphragm is gradually reduced from the starting end to the tail end in length or the thickness of the diaphragm is sequentially reduced from the starting end to the uniform thickness, and the thickness of the diaphragm reaches the tail end after a certain length is kept.

Furthermore, the diaphragm is arranged on the battery core in a winding manner from the starting end.

Preferably, the total length of the diaphragm is L, the starting ends are sequentially decreased to a length L1 with uniform thickness, and L1 is half of L.

Compared with the prior art, the utility model has the advantages and positive effect be:

the utility model can improve the soaking effect of the pole piece at the part with larger stress by the electrolyte and adapt to the stress at the part, thereby improving the cycle performance of the battery, reducing the risk of lithium precipitation and improving the safety; and ensure that the rear diaphragm maintains certain tensile strength and ensures the reliability of electronic insulation.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without inventive exercise.

Fig. 1 is a schematic structural diagram of embodiment 1 of the present invention;

fig. 2 is a schematic structural diagram of embodiment 2 of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention; the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying any relative importance, and furthermore, unless otherwise explicitly stated or limited, the terms "mounted," "connected," and "connected" are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Example 1:

as shown in figure 1 of the drawings, in which,

the diaphragm for improving the performance of the cylindrical lithium ion battery sequentially reduces the thickness of the diaphragm from the starting end to uniform thickness in length, keeps a section of length and then reaches the tail end.

In this embodiment, the diaphragm is wound around the battery cell from the start end.

In this embodiment, the total length of the diaphragm is L, the starting end sequentially decreases to a length L1 with a uniform thickness, and L1 is half of L.

During winding, the length of the diaphragm is adjusted to enable the diaphragm at the starting end to correspond to the winding end of the battery, then winding is started, winding is completed after the winding is finished to the tail end, and when the next battery is wound, the winding end still corresponds to the diaphragm at the starting end of the next diaphragm, and winding is repeated.

The utility model discloses the theory of operation: the stress of the front winding section of the battery core is larger, the thickness of the diaphragm corresponding to the part L1 is thicker, the diaphragm thickness of the part after stretching is thinner and is consistent with that of the diaphragm of the rear half section, and the stress is reduced along with the increase of the winding length of the pole piece, so that the thickness of the diaphragm is thinner and is consistent with that of the diaphragm of the front half section L1; although the thicker part of the diaphragm is compressed when the stress is larger, the thicker part can still ensure larger pores to provide an electrolyte storage space and a charged cathode sheet expansion buffer space, so that the pole sheet soaking effect of the part with larger stress by the electrolyte is improved, the stress of the part is adapted, the cycle performance of the battery is improved, the risk of lithium precipitation is reduced, and the safety is improved; when the length of the membrane is wound to be half of the total membrane length, the thickness of the membrane is kept constant, the membrane at the rear section is ensured to maintain certain tensile strength, and the reliability of electronic insulation is ensured.

Example 2:

as shown in figure 2 of the drawings, in which,

a separator for improving the performance of a cylindrical lithium ion battery, wherein the thickness of the separator gradually decreases from the starting end to the tail end in length.

The utility model discloses the theory of operation: the stress of electric core coiling diminishes from big, and diaphragm thickness reduces from the initiating terminal to the tail end gradually, and then the diaphragm thickness attenuation of this position after the drawing has kept unanimous with the diaphragm thickness of second half section to the great aperture can be guaranteed to the diaphragm, with the negative pole piece inflation buffer space after providing electrolyte storage space and charging, thereby improve the great position pole piece of stress and be soaked the effect by electrolyte and reduce this position stress, thereby promote battery cycle performance, and reduce and analyse lithium risk and improve the security.

Based on the embodiments of the present invention, any modifications, equivalent replacements, improvements, etc. made by other embodiments obtained by a person of ordinary skill in the art without creative efforts shall be included in the protection scope of the present invention.

Claims

1. The utility model provides a promote diaphragm of cylinder lithium ion battery performance which characterized in that: the thickness of the diaphragm gradually decreases from the starting end to the tail end in length or the thickness of the diaphragm sequentially decreases from the starting end to uniform thickness and reaches the tail end after a certain length is maintained.

2. The separator for improving the performance of the cylindrical lithium ion battery according to claim 1, wherein: the diaphragm is wound on the battery cell from the starting end.

3. The separator for improving the performance of the cylindrical lithium ion battery according to claim 1, wherein: the total length of the diaphragm is L, the starting end of the diaphragm is sequentially reduced to the length of uniform thickness which is L1, and the L1 is half of the L.