CN216288828U

CN216288828U - Battery diaphragm structure and battery thereof

Info

Publication number: CN216288828U
Application number: CN202122839515.9U
Authority: CN
Inventors: 张欢欢; 张志平; 徐宁; 高旭光; 李宗植
Original assignee: Dongguan K Tech New Energy Co ltd; Guangdong Greenway Technology Co Ltd
Current assignee: Dongguan K Tech New Energy Co ltd; Guangdong Greenway Technology Co Ltd
Priority date: 2021-11-19
Filing date: 2021-11-19
Publication date: 2022-04-12
Anticipated expiration: 2031-11-19

Abstract

The utility model relates to the technical field of battery structures, and discloses a battery diaphragm structure and a battery thereof. The diaphragm structure is special micron order siphonozooid can be well with electrolyte absorption storage in the body, and the siphonozooid is the axial and switches on, and this structural design helps electrolyte to switch on in the axial infiltration of electric core to help the infiltration of electric core pole piece more complete on axial position, the infiltration effect is better, makes electric core performance obtain promoting.

Description

Battery diaphragm structure and battery thereof

Technical Field

The utility model relates to the technical field of battery structures, in particular to a battery diaphragm structure and a battery thereof.

Background

At present, the design of batteries gradually begins to rapidly develop towards the direction of multiple models and large sizes, when chemical systems related to the design of the batteries are similar, the large-size design of the batteries can reduce the occupation ratio of structural members and obtain higher specific capacity density, and meanwhile, the battery PACK grouping is greatly facilitated. Along with the increase of the design size of the battery, the difficulty of the liquid injection process of the lithium ion battery with larger size, especially the cylindrical lithium ion battery, is greatly increased, the wettability of the electrolyte at the axial middle position of the winding core is poor, so that the capacity performance is poor, and even the risks of lithium precipitation of a negative pole piece and the like can occur.

For the problems caused by the intrinsic characteristics of the cell size selection, the cell structure design and the like, the optimization of process parameters and a winding core structure is carried out, and the diaphragm in a material system is also an effective way for improving the cell performance. At present, most commercial lithium ion battery diaphragm products are polyolefin microporous membranes, including Polyethylene (PE) single-layer membranes, polypropylene (PP) single-layer membranes and PP/PE/PP multi-layer microporous membranes compounded by PP and PE. Generally, a conventional way for improving the wettability of the diaphragm is to coat an inorganic ceramic layer or a PVDF layer on the surface of a base film or compound other materials with good liquid absorption and retention properties, for example, in patent CN105552277B, low-viscosity aqueous PVDF slurry is coated on the surface of the base film to form an ultrathin coating with orderly arranged PVDF particles and relatively loose PVDF particles, and the diaphragm can effectively improve the hardness of the diaphragm; patent CN109585750A proposes a composite membrane of a polymer and a base membrane, the polymer such as perfluorosulfonic acid polymer,One of sulfonated polyphosphazene and sulfonated polyether ether ketone permeates into micropores on the surface of a PP membrane, a PE membrane or a PP and PE composite porous membrane. Patent CN107768582A proposes using nano Al₂O₃The combination of the layer and the nano high-purity alumina layer improves the heat shrinkage, puncture, free HF neutralization and liquid absorption and retention capacity of the whole membrane.

In the technical scheme of the patent, a coating is mainly formed on the surface of the diaphragm or a certain modified substance is added, but the bonding force between the coating and the base film is weak, so that the overall performance of the battery is reduced in the circulation process. And the introduction of the modified substance easily causes side reactions in the battery, thereby increasing the safety risk. Because of this, the choice of the coating material and the modifying substance is limited by the material system used in the battery, the choice range is narrow, and the versatility of the corresponding separator is low.

Disclosure of Invention

The utility model aims to overcome the defects of the prior art and provide a battery diaphragm structure which can help a battery cell to more completely infiltrate pole pieces at an axial position, has better infiltration effect and does not need coating on the surface of a diaphragm.

The purpose of the utility model is realized by the following technical scheme:

the utility model provides a battery diaphragm structure, the cladding is in electric core periphery, and diaphragm structure has first rete and second rete, and the structural interval arrangement that is of diaphragm has a plurality of splice bars parallel with electric core axis, and the splice bar is with first rete and the inseparable laminating of second rete for form between first rete and the second rete a plurality of siphonozooids and adjacent siphonozooid each other and link up, the arrangement of splice bar can satisfy each siphonozooid diameter and be the micron order.

Furthermore, the first film layer and the second film layer are made of the same material.

Furthermore, the first film layer and the second film layer are different in material.

Furthermore, the connecting rib is formed by attaching the first film layer and the second film layer through a thermal shrinkage or adhesion process.

Further, the diaphragm structure is formed in one step through a die.

Further, the arrangement of each connecting rib can meet the requirement that the tubular bodies are densely arranged on the diaphragm structure.

Compared with the prior art, the utility model has the following beneficial effects:

1) the special micron-sized tubular body on the diaphragm structure can well absorb and store the electrolyte in the tubular body, and the tubular body is in axial conduction, so that the structural design is beneficial to the axial infiltration and conduction of the electrolyte in the battery cell, the battery cell is more completely infiltrated on the axial position of a pole piece, the infiltration effect is better, and the performance of the battery cell is improved;

2) the diaphragm structure is directly formed by the first film layer and the second film layer through a special process, coating of each film layer is not needed, other materials cannot be introduced, side reaction risks can be effectively avoided, and the battery is guaranteed to have high safety and good applicability.

Drawings

Fig. 1 is a schematic diagram of a battery separator structure according to embodiment 1 coated on a battery cell;

FIG. 2 is a front view of a battery separator structure in example 1;

fig. 3 is a top view of the view of fig. 2.

Detailed Description

The present invention will be further described with reference to the following detailed description, wherein the drawings are provided for illustrative purposes only and are not intended to be limiting; to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.

Example 1

The utility model provides a battery, be equipped with like the diaphragm structure shown in fig. 2 and fig. 3, in fig. 1, this diaphragm structure 1 cladding is in 2 peripheries of electric core, diaphragm structure 1 has first rete 11 and second rete 12, the structural interval arrangement of diaphragm has a plurality of splice bar 13 that parallel with 2 axis of electric core simultaneously, splice bar 13 is with first rete and the inseparable laminating of second rete, make form between first rete 11 and the second rete 12 a plurality of siphonozooid 3 and adjacent siphonozooid 3 each other do not link up, wherein, the arrangement of splice bar 13 can satisfy each siphonozooid 3 diameter and be the micron order, the internal diameter size of micron order siphonozooid can be according to actual demand, combine into originally and formulate different sizes.

The manufacturing process of the film structure can be expressed as follows: two film layers are selected as a first film layer and a second film layer, the first film layer and the second film layer are discontinuously jointed through a thermal shrinkage or adhesion process or other suitable processes, and a connecting rib is formed at the joint. In order to ensure complete infiltration of the battery core, the arrangement of the connecting ribs needs to meet the requirement that the tubular bodies are densely arranged on the diaphragm structure; preferably, the connecting ribs are uniformly arranged on the whole of the diaphragm structure. Viewed from the whole, the diaphragm structure consists of two film layers, gaps (tubular bodies) for storing the electrolyte are continuously and regularly reserved between the layers through connecting ribs, and each tubular body is communicated along the self axial direction; after liquid injection, a part of electrolyte can slowly settle to the bottom of the battery under the action of gravity, and the existence of the axially-through micron-sized tubular body can enable the electrolyte at the bottom of the battery to rise to the upper part of the battery under the action of capillary effect, so that the electrolyte has good circulation guiding effect on the infiltration of the electrolyte at the axial position, the electrolyte can be more fully infiltrated into a battery pole piece, the problem that the infiltration of the electrolyte at the axial middle position is not in place in the production process of a large-size battery is solved, the liquid injection difficulty is reduced, and the infiltration effect is improved.

In addition, the design of the double-membrane-layer structure of the diaphragm structure can lead the thickness of each layer of diaphragm to be biased to be thinner for selection, thereby being beneficial to the infiltration of electrolyte in the diaphragm to the pole pieces on two sides.

Generally, the electrolyte injection process is performed under normal atmospheric pressure, so that the diaphragm structure can better absorb and store the electrolyte in the tubular body, and then the electrolyte stored in the tubular body is immersed in the pole piece by changing the air pressure.

The first film layer 11 and the second film layer 12 may be made of the same material, or made of different materials with better adaptability to corresponding positive and negative electrode plates of the battery according to the difference between the positive and negative electrode plates.

The diaphragm structure is applied to lithium ion batteries or other types such as sodium ion batteries, particularly cylindrical or square batteries with larger axial size, can well improve the problem of difficult electrolyte infiltration, particularly insufficient electrolyte infiltration at the axial middle position, has simple method, does not need to increase additional components, does not influence the normal working procedure in battery production in use, does not need to additionally increase the pressurizing strength and the pressurizing time in the liquid injection stage, and saves the production time and the cost.

It should be noted that: the above-described separator structure can be realized not only in a base film but also in a coated separator.

Example 2

In this embodiment, the first film layer and the second film layer in the diaphragm structure do not need to be subjected to the operations of heat shrinking, adhesion and the like as in embodiment 1, but are formed into the tubular body and the connecting ribs in one step through a mold.

It should be understood that the above examples are only for clearly illustrating the technical solutions of the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. The utility model provides a battery diaphragm structure, the cladding is in electric core periphery, its characterized in that, diaphragm structure has first rete and second rete, and the structural interval arrangement that is of diaphragm has a plurality of splice bars parallel with electric core axis, and the splice bar is with first rete and the inseparable laminating of second rete for form between first rete and the second rete a plurality of siphonozooids and adjacent siphonozooid each other and link up, the arrangement of splice bar can satisfy that each siphonozooid diameter is the micron order.

2. The battery separator structure of claim 1, wherein the first and second film layers are the same material.

3. The battery separator structure of claim 1 wherein the first and second film layers are of different materials.

4. The battery separator structure of claim 1, wherein the tie bar is formed by attaching the first film layer and the second film layer by a heat shrinking or adhering process.

5. The battery separator structure of claim 1, wherein the separator structure is formed in one piece by a mold.

6. The battery separator structure of claim 1, wherein the arrangement of the connecting ribs is such that the tubular bodies are closely spaced on the separator structure.

7. A battery having a battery separator structure according to any one of claims 1 to 6.