CN219067141U

CN219067141U - Diaphragm, battery cell and electric equipment

Info

Publication number: CN219067141U
Application number: CN202223386632.5U
Authority: CN
Inventors: 陆蓓; 何星星; 请求不公布姓名; 庄思东
Original assignee: Jiangsu Zenio New Energy Battery Technologies Co Ltd
Current assignee: Jiangsu Zenio New Energy Battery Technologies Co Ltd
Priority date: 2022-12-15
Filing date: 2022-12-15
Publication date: 2023-05-23
Anticipated expiration: 2032-12-15

Abstract

The utility model belongs to the technical field of batteries, and discloses a diaphragm, an electric core and electric equipment. The diaphragm comprises a diaphragm body, wherein at least one surface of the diaphragm body is coated with a diaphragm coating; wherein the membrane coating comprises a first coating and a second coating, the first coating comprising a plurality of coating stripes spaced apart along a first direction; the second coating extends along the first direction, the coating strip and the second coating are sequentially connected along the second direction, the first direction is the length direction of the diaphragm body, and the second direction is the width direction of the diaphragm body. The diaphragm can improve the infiltration efficiency when the battery cell is infiltrated with electrolyte, and can always maintain the storage quantity of the electrolyte above the battery cell when the battery cell is used for a long time, so that the phenomena of deposition of the electrolyte at the lower layer and insufficient electrolyte at the upper layer can not occur, and the service life and the reliability of the battery cell are improved.

Description

Diaphragm, battery cell and electric equipment

Technical Field

The utility model relates to the technical field of batteries, in particular to a diaphragm, a battery core and electric equipment.

Background

Along with the improvement of energy conservation and emission reduction demands and energy demands of people, lithium ion batteries are widely paid attention to due to the advantages of high working voltage, high energy density, long cycle life, low self-discharge rate and the like. A lithium ion battery is a secondary battery composed of a positive electrode, a negative electrode, a separator, and an electrolyte. The separator is a very critical part of a lithium ion battery, and is mainly used for isolating the anode and the cathode of the battery, allowing ions in electrolyte to pass freely between the anode and the cathode and isolating electrons.

In the process of producing the lithium ion battery, a method of standing for a long time is generally used after electrolyte is injected into the battery core, so that the electrolyte accumulated above the electrolyte is permeated downwards during the injection, the battery core is fully permeated, and the production efficiency of the method is lower; in addition, in the long-time charging and discharging process of the lithium ion battery, due to the action of gravity, electrolyte on the upper layer of the battery has a downward deposition tendency, so that the storage capacity of the electrolyte on the upper layer is insufficient, and the cycle performance of the battery is further affected.

Therefore, it is needed to provide a novel separator to solve the technical problems of low cell infiltration efficiency and downward electrolyte deposition in long-term use of the cells in the prior art.

Disclosure of Invention

The utility model aims to provide a diaphragm, which can improve the infiltration efficiency when an electric core is infiltrated, always maintain the storage quantity of electrolyte above the electric core when the electric core is used for a long time and improve the service life and the reliability of the electric core.

To achieve the purpose, the utility model adopts the following technical scheme:

the diaphragm comprises a diaphragm body, wherein at least one surface of the diaphragm body is coated with a diaphragm coating; wherein the separator coating comprises a first coating and a second coating, the first coating comprises a plurality of coating strips which are distributed at intervals along a first direction; the coating strip and the second coating are sequentially connected along a second direction; the first direction is a longitudinal direction of the diaphragm body, and the second direction is a width direction of the diaphragm body.

Optionally, the diaphragm body includes a first surface and a second surface disposed opposite to each other, and the first surface and the second surface are coated with the diaphragm coating.

Optionally, the coating strips on the first surface are offset from the coating strips on the second surface.

Optionally, the dimension of the coating strips along the first direction is W1, and the gap distance between two adjacent coating strips along the first direction is W2, W2 > W1, W1 is 3 μm or less and is 3mm or less, and W2 is 5 μm or less and is 5mm or less.

Optionally, a plurality of the above-mentioned coating strips are equally wide and equally spaced.

Optionally, the dimension of the coating strip along the second direction is H1, and the dimension of the second coating along the second direction is H2, and H1/H2 is more than or equal to 0.05 and less than or equal to 1.

Optionally, the liquid absorbing capacity of the coating strip is greater than the liquid absorbing capacity of the second coating.

Optionally, the coated strip is coated with a nanofiber coating and the second coating is coated with polyvinylidene fluoride

Another object of the present utility model is to provide a battery cell including a positive electrode sheet, a negative electrode sheet, and a separator according to any one of the above aspects, the separator being interposed between the positive electrode sheet and the negative electrode sheet.

It is a further object of the present utility model to provide a powered device comprising a battery cell as described in the above-mentioned aspects.

The beneficial effects are that:

the diaphragm body is coated with the diaphragm coating, the diaphragm coating comprises the first coating and the second coating, when electrolyte is injected into the battery cell applying the diaphragm, namely the electrolyte sequentially passes through the first coating and the second coating, the electrolyte can gradually infiltrate by means of gravity and can flow downwards from gaps among the coating strips and gradually infiltrate, so that the infiltration efficiency is improved, and the production efficiency of the finally formed battery cell is improved; after the electrolyte completely infiltrates the diaphragm, the electrolyte is locked in the gaps between the coating strips through capillary force, so that the stable electrolyte remaining amount of the upper layer of the battery cell is ensured all the time when the battery cell is vertically placed, the circulation stability of the battery cell is ensured, and the service life and the service reliability of the battery cell using the diaphragm are improved.

Drawings

FIG. 1 is an isometric schematic view of a diaphragm provided in an embodiment of the present utility model;

FIG. 2 is a top view of a diaphragm provided in an embodiment of the present utility model;

fig. 3 is a rear view of a diaphragm provided in an embodiment of the present utility model.

In the figure:

100. a diaphragm body; 101. a first surface; 102. a second surface; 110. a coating strip; 120. and (3) a second coating.

Detailed Description

The utility model is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the utility model and are not limiting thereof. It should be further noted that, for convenience of description, only some, but not all of the structures related to the present utility model are shown in the drawings.

In the description of the present utility model, unless explicitly stated and limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present utility model will be understood in specific cases by those of ordinary skill in the art.

In the present utility model, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or simply means that the first feature is less level than the second feature.

In the description of the present embodiment, the terms "upper", "lower", "right", etc. orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are merely for convenience of description and simplicity of operation, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the utility model. Furthermore, the terms "first," "second," and the like, are used merely for distinguishing between descriptions and not for distinguishing between them.

The first direction in this embodiment is the X direction described in fig. 1 and 2, that is, the length direction of the diaphragm; the Y direction shown in the second direction bitmap 1, i.e., the width direction of the separator.

Referring to fig. 1, in the present embodiment, the diaphragm includes a diaphragm body 100, and at least one surface of the diaphragm body 100 is coated with a diaphragm coating; wherein the separator coating comprises a first coating and a second coating 120, the first coating comprising a plurality of coating stripes 110 spaced apart along a first direction; the second coating layer 120 is extended along the first direction, and the coating bar 110 and the second coating layer 120 are sequentially connected along a second direction.

The diaphragm body 100 in this embodiment is coated with a diaphragm coating including a first coating layer and a second coating layer 120 sequentially disposed in a second direction; when electrolyte is injected into the battery cell using the diaphragm, the battery cell is in a standing state, and the width direction (namely the second direction) of the diaphragm is a vertical direction at the moment, that is, the electrolyte sequentially passes through the first coating and the second coating and is injected into the battery cell, and as the first coating is a plurality of coating strips 110 distributed at intervals, the electrolyte can gradually infiltrate by means of gravity and can flow downwards from gaps among the coating strips 110 and gradually infiltrate, so that the infiltration efficiency is improved, and the production efficiency of the finally formed battery cell is improved; after the electrolyte completely infiltrates the diaphragm, the electrolyte is locked in the gaps between the coating strips 110 through capillary force, so that the stable electrolyte remaining amount of the upper layer of the battery cell is ensured all the time when the battery cell is vertically placed, the circulation stability of the battery cell is ensured, and the service life and the service reliability of the battery cell using the diaphragm are improved.

The specific structural and dimensional parameters of the membrane coating of the membrane in this embodiment are described in detail below in conjunction with fig. 2. In this embodiment, the coating strip 110 is in a strip shape, such as a serpentine strip shape or a rectangular strip shape, and the coating strip 110 may be perpendicular to the X direction or may be set at a certain inclination angle. Specifically, the plurality of the coating stripes 110 are arranged at equal widths and equal intervals. The first coating layer thus provided can be directly pressed on the diaphragm body 100 using the pressing roller, and is simple and convenient to operate, and can reduce production cost.

Specifically, the dimension of the coating bar 110 in the first direction is W1, the gap distance between two adjacent coating bars 110 in the first direction is W2, W1 is 3 μm or less and 3mm or less, and W2 is 5 μm or less and 5mm or less. The coating strip 110 that sets up like this can guarantee good capillary effect, and the electrolyte of being convenient for soaks to second coating 120 from first coating department to and be convenient for promote the electrolyte to first coating department through capillary force effect, improved the life and the reliability of use of the electric core of this diaphragm.

As a preferred embodiment, the dimension of the coating strip 110 in the second direction is H1, and the dimension of the second coating 120 in the second direction is H2, 0.05.ltoreq.H2.ltoreq.1. The first coating and the second coating 120 arranged in this way can ensure that the area occupied by the second coating 120 on the diaphragm body 100 is at least half, so that the electrolyte can be stored in a large enough area, the electrolyte capacity of the battery cell is not affected, and the service performance of the battery cell is not affected.

With continued reference to fig. 3, optionally, the diaphragm body 100 includes a first surface 101 and a second surface 102 disposed opposite to each other, and each of the first surface 101 and the second surface 102 is coated with the diaphragm coating. The two surfaces of the diaphragm body 100 are provided with the diaphragm coating, so that the infiltration capacity of electrolyte can be improved from the two surfaces of the diaphragm, the infiltration efficiency is further improved, and the production efficiency of the finally formed battery cell is improved; after the battery cell is manufactured by the diaphragm, as the diaphragm coatings are arranged on the two surfaces of the diaphragm body 100, the whole diaphragm can be soaked by electrolyte more quickly, the phenomenon that the electrolyte on the upper part of the battery cell is insufficient due to the deposition of the electrolyte can be further improved, and the service life and the service reliability of the battery cell using the diaphragm are improved.

Alternatively, the coating stripes 110 on the first surface 101 are offset from the coating stripes 110 on the second surface 102. Further, the width of the coating strip 110 is W1, and the width of the gap between two adjacent coating strips 110 is W2, where W2 > W1. The coating strips 110 arranged in this way prevent the coating strips 110 on the upper and lower surfaces of the diaphragm body 100 from covering each other, and reduce the total area of the first coating on the upper and lower surfaces on the premise of ensuring the infiltration efficiency and the capillary effect of the upper and lower surfaces, thereby reducing the material cost of production and the total production cost of the diaphragm.

Optionally, the wicking ability of the coated strip 110 is greater than the wicking ability of the second coating 120. Specifically, the coated strip 110 is coated with a nanofiber coating, and the second coating 120 is coated with polyvinylidene fluoride. The nanofiber coating is characterized in that nanoscale fibers are coated on a base film, and the surface of the existing diaphragm or non-woven fabric base fabric is modified, so that on one hand, the high-temperature shrinkage resistance of the diaphragm can be improved, on the other hand, the electrode compatibility and the cohesiveness of the battery diaphragm can be improved, the absorption and the affinity of the diaphragm to electrolyte are improved, and compared with a polyvinylidene fluoride (PVDF) coating, the nanofiber coating has stronger liquid absorption capacity and can improve the electrolyte infiltration efficiency and the capillary property; of course, other materials may be used, so long as the coating has good liquid absorption performance and electrolyte corrosion resistance, and the embodiment will not be described again. The second coating 120 formed by coating the polyvinylidene fluoride material plays a role of interfacial bonding and maintaining the cell structure stability, and among other optional materials, such as ceramic coating, aqueous PVDF coating, aramid coating or oil-based PVDF coating, the embodiment is not particularly limited.

The following describes the method for manufacturing the separator in this embodiment in detail:

first, a second coating layer 120 of PVDF material is uniformly applied to one end of the separator body 100 in the machine running direction (Machine Direction, MD direction, i.e., X direction in fig. 1 and 2); then, a first coating layer of a regular strip shape is rolled out in the X direction using a striped coating roller; finally, both surfaces of the diaphragm body 100 may be coated simultaneously or sequentially.

The embodiment also provides a battery cell, which comprises a positive plate, a negative plate and the diaphragm according to any one of the schemes, wherein the diaphragm is arranged between the positive plate and the negative plate in a spaced mode. The battery core is a winding battery core or a lamination battery core, the winding battery core is selected in the embodiment, and the structure of the battery core is conventional in the art, and is not repeated here. The battery cell uses the diaphragm according to the scheme, the production speed can be increased, the production efficiency is improved, electrolyte deposition is not easy to occur in the use process of the battery cell, the electrolyte is kept uniform in the battery cell, and the service life and the reliability of the battery cell are improved.

When the battery core is formed by winding or the battery core is formed by laminating, a strip-shaped structure of a first coating of the diaphragm is contacted with the positive electrode plate and the negative electrode plate to form a regular rectangular capillary structure, and when the capillary is smaller, the capillary force is stronger, so that the structure can overcome the gravity effect to firmly adsorb electrolyte at the lower layer in the capillary, and the liquid retention amount of the upper layer of the battery core in the long-time charge and discharge process is ensured; and because the lower layer of the membrane is the complete second coating 120, alignment issues with the upper layer of the membrane need not be considered.

The embodiment also provides electric equipment, which comprises the electric core according to the scheme. By using the electric equipment with the battery core in the embodiment, the service life and the reliability of the battery core can be improved.

It is to be understood that the above examples of the present utility model are provided for clarity of illustration only and are not limiting of the embodiments of the present utility model. Various obvious changes, rearrangements and substitutions can be made by those skilled in the art without departing from the scope of the utility model. It is not necessary here nor is it exhaustive of all embodiments. Any modification, equivalent replacement, improvement, etc. which come within the spirit and principles of the utility model are desired to be protected by the following claims.

Claims

1. A separator, comprising:

a diaphragm body (100), the diaphragm body (100) having a diaphragm coating coated on at least one surface thereof;

wherein the separator coating comprises a first coating and a second coating (120), the first coating comprising a plurality of coating stripes (110) spaced apart along a first direction; the second coating (120) extends along the first direction, and the coating strips (110) are sequentially connected with the second coating (120) along a second direction; the first direction is the length direction of the diaphragm body (100), and the second direction is the width direction of the diaphragm body (100).

2. The membrane according to claim 1, characterized in that the membrane body (100) comprises a first surface (101) and a second surface (102) arranged opposite each other, both the first surface (101) and the second surface (102) being coated with the membrane coating.

3. The membrane according to claim 2, characterized in that the coating strips (110) on the first surface (101) are arranged offset from the coating strips (110) on the second surface (102).

4. A membrane according to claim 3, characterized in that the dimension of the coating strips (110) in the first direction is W1, the gap distance between two adjacent coating strips (110) in the first direction is W2, W2 > W1,3 μm ∈w1 ∈3mm,5 μm ∈w2 ∈5mm.

5. The membrane according to any one of claims 1-4, characterized in that a plurality of said coating strips (110) are equally wide and equally spaced.

6. The membrane of any one of claims 1-4, wherein the dimension of the coating strip (110) along the second direction is H1, and the dimension of the second coating (120) along the second direction is H2, 0.05-1/H2-1.

7. The membrane according to any one of claims 1-4, characterized in that the liquid absorbing capacity of the coating strip (110) is stronger than the liquid absorbing capacity of the second coating (120).

8. The membrane of claim 7, wherein the coating strip (110) is coated with a nanofiber coating and the second coating (120) is coated with polyvinylidene fluoride.

9. The battery cell is characterized by comprising a positive plate, a negative plate and the diaphragm as claimed in any one of claims 1-8, wherein the diaphragm is arranged between the positive plate and the negative plate in a spacing way.

10. A powered device comprising the electrical cell of claim 9.