CN220041956U

CN220041956U - Battery cell and battery

Info

Publication number: CN220041956U
Application number: CN202321500471.XU
Authority: CN
Inventors: 赵冬
Original assignee: China Innovation Aviation Technology Group Co ltd
Current assignee: China Innovation Aviation Technology Group Co ltd
Priority date: 2023-06-12
Filing date: 2023-06-12
Publication date: 2023-11-17
Anticipated expiration: 2033-06-12

Abstract

The utility model relates to the technical field of batteries, and provides a battery cell and a battery. The electric core includes: a first diaphragm; a first pole piece; the first diaphragm and the second diaphragm are both arranged beyond the first pole piece, so that the first diaphragm and the second diaphragm are bonded; the first diaphragm and the first pole piece are bonded and encapsulated, the peeling strength between the first diaphragm and the first pole piece is 5N/m-800N/m, and/or the peeling strength between the second diaphragm and the first pole piece is 5N/m-800N/m, the wrinkling risk is further reduced on the basis of ensuring that at least one of the first diaphragm and the second diaphragm is reliably connected with the first pole piece, the first pole piece can be ensured to expand in the charging and discharging process of the battery cell, the risk of material dropping caused by stress concentration of the first pole piece is reduced, and therefore the safety service performance of the battery cell can be effectively improved.

Description

Battery cell and battery

Technical Field

The utility model relates to the technical field of batteries, in particular to a battery cell and a battery.

Background

In the related art, the battery cell can include first pole piece, second pole piece and diaphragm, and the diaphragm realizes the insulation protection to first pole piece and second pole piece, because diaphragm and pole piece connectivity restriction, the risk that the pole piece stress concentration leads to falling the material probably appears, or the softer diaphragm that probably appears the diaphragm wrinkling leads to causing the inside security risk of battery.

Disclosure of Invention

The utility model provides a battery cell and a battery, which are used for improving the service performance of the battery cell.

According to a first aspect of the present utility model, there is provided a cell comprising:

a first diaphragm;

a first pole piece;

the first diaphragm and the second diaphragm are both arranged beyond the first pole piece, so that the first diaphragm and the second diaphragm are bonded and encapsulated with the first pole piece;

wherein the first diaphragm and the first pole piece are bonded, the peeling strength between the first diaphragm and the first pole piece is 5N/m-800N/m, and/or the second diaphragm and the first pole piece are bonded, and the peeling strength between the second diaphragm and the first pole piece is 5N/m-800N/m.

The battery cell provided by the embodiment of the utility model comprises the first diaphragm, the first pole piece and the second diaphragm, wherein the first pole piece is positioned between the first diaphragm and the second diaphragm, so that insulation protection on the first pole piece is formed, the first diaphragm and the second diaphragm are arranged beyond the first pole piece, and the first diaphragm and the second diaphragm are bonded and encapsulated with the first pole piece, so that the risk of wrinkling of the first diaphragm and the second diaphragm can be reduced, and reliable insulation protection on the first pole piece can be formed. The first diaphragm and the first pole piece are bonded, the peeling strength between the first diaphragm and the first pole piece is 5N/m-800N/m, and/or the peeling strength between the second diaphragm and the first pole piece is 5N/m-800N/m, so that the risk of wrinkling is further reduced on the basis of ensuring that at least one of the first diaphragm and the second diaphragm is reliably connected with the first pole piece, the first pole piece can be expanded in the charging and discharging process of the battery cell, the risk of material dropping caused by stress concentration of the first pole piece is reduced, and the safe use performance of the battery cell can be effectively improved.

According to a second aspect of the present utility model, there is provided a battery comprising the above-described cell.

The battery cell of the battery comprises the first diaphragm, the first pole piece and the second diaphragm, wherein the first pole piece is positioned between the first diaphragm and the second diaphragm, so that insulation protection of the first pole piece is formed, the first diaphragm and the second diaphragm are arranged beyond the first pole piece, the first diaphragm and the second diaphragm are bonded and encapsulate the first pole piece, the wrinkling risk of the first diaphragm and the second diaphragm can be reduced, and reliable insulation protection of the first pole piece can be formed. The first diaphragm and the first pole piece are bonded, the peeling strength between the first diaphragm and the first pole piece is 5N/m-800N/m, and/or the peeling strength between the second diaphragm and the first pole piece is 5N/m-800N/m, so that the risk of wrinkling is further reduced on the basis of ensuring that at least one of the first diaphragm and the second diaphragm is reliably connected with the first pole piece, the first pole piece can be expanded in the charging and discharging process of the battery core, the risk of material dropping caused by stress concentration of the first pole piece is reduced, and the safe service performance of the battery can be effectively improved.

Drawings

For a better understanding of the present disclosure, reference may be made to the embodiments illustrated in the following drawings. The components in the drawings are not necessarily to scale and related elements may be omitted in order to emphasize and clearly illustrate the technical features of the present disclosure. In addition, the relevant elements or components may have different arrangements as known in the art. Furthermore, in the drawings, like reference numerals designate identical or similar parts throughout the several views.

Wherein:

fig. 1 is a schematic view of a structure of a battery according to a first exemplary embodiment;

fig. 2 is a schematic structural view of a battery according to a second exemplary embodiment;

fig. 3 is a schematic view of a structure of a battery according to a third exemplary embodiment;

fig. 4 is a partial structural schematic diagram showing one view of a battery cell of a battery according to an exemplary embodiment;

fig. 5 is a partial schematic structural view showing another view of the cell of a battery according to an exemplary embodiment;

FIG. 6 is a partially exploded view of the cells of a battery according to an exemplary embodiment;

fig. 7 is a partial schematic structure of a battery cell of a battery according to another exemplary embodiment.

The reference numerals are explained as follows:

10. a first diaphragm; 20. a first pole piece; 30. a second diaphragm; 40. a first tab; 50. a second pole piece; 60. a battery case; 70. a second lug; 80. and a pole assembly.

Detailed Description

The technical solutions in the exemplary embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings in the exemplary embodiments of the present disclosure. The example embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the present disclosure, and it is therefore to be understood that various modifications and changes may be made to the example embodiments without departing from the scope of the present disclosure.

In the description of the present disclosure, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance unless explicitly specified or limited otherwise; the term "plurality" refers to two or more than two; the term "and/or" includes any and all combinations of one or more of the associated listed items. In particular, references to "the/the" object or "an" object are likewise intended to mean one of a possible plurality of such objects.

Unless specified or indicated otherwise, the terms "connected," "fixed," and the like are to be construed broadly and are, for example, capable of being fixedly connected, detachably connected, or integrally connected, electrically connected, or signally connected; "coupled" may be directly coupled or indirectly coupled through intermediaries. The specific meaning of the terms in the present disclosure may be understood by those skilled in the art according to the specific circumstances.

Further, in the description of the present disclosure, it should be understood that the terms "upper", "lower", "inner", "outer", and the like, as described in the example embodiments of the present disclosure, are described with the angles shown in the drawings, and should not be construed as limiting the example embodiments of the present disclosure. It will also be understood that in the context of an element or feature being connected to another element(s) "upper," "lower," or "inner," "outer," it can be directly connected to the other element(s) "upper," "lower," or "inner," "outer," or indirectly connected to the other element(s) "upper," "lower," or "inner," "outer" via intervening elements.

An embodiment of the present utility model provides a battery cell, please refer to fig. 1 to 7, the battery cell includes: a first diaphragm 10; a first pole piece 20; a second diaphragm 30, a first pole piece 20 is arranged between the first diaphragm 10 and the second diaphragm 30, and the first diaphragm 10 and the second diaphragm 30 are arranged beyond the first pole piece 20, so that the first diaphragm 10 and the second diaphragm 30 are bonded and encapsulate the first pole piece 20; wherein the first diaphragm 10 and the first pole piece 20 are bonded, the peel strength between the first diaphragm 10 and the first pole piece 20 is 5N/m-800N/m, and/or the second diaphragm 30 and the first pole piece 20 are bonded, and the peel strength between the second diaphragm 30 and the first pole piece 20 is 5N/m-800N/m.

The battery cell of one embodiment of the utility model comprises a first diaphragm 10, a first diaphragm 20 and a second diaphragm 30, wherein the first diaphragm 20 is positioned between the first diaphragm 10 and the second diaphragm 30, thereby forming insulation protection for the first diaphragm 20, the first diaphragm 10 and the second diaphragm 30 are arranged beyond the first diaphragm 20, and the first diaphragm 10 and the second diaphragm 30 are bonded and encapsulated with the first diaphragm 20, so that the wrinkling risk of the first diaphragm 10 and the second diaphragm 30 can be reduced, and reliable insulation protection for the first diaphragm 20 can be formed. Because the first diaphragm 10 is bonded with the first pole piece 20, the peel strength between the first diaphragm 10 and the first pole piece 20 is 5N/m-800N/m, and/or the peel strength between the second diaphragm 30 and the first pole piece 20 is 5N/m-800N/m, on the basis of ensuring that at least one of the first diaphragm 10 and the second diaphragm 30 is reliably connected with the first pole piece 20, the wrinkling risk is further reduced, the first pole piece 20 can be ensured to expand in the charging and discharging process of the battery cell, the risk of material dropping caused by stress concentration of the first pole piece 20 is reduced, and therefore the safe use performance of the battery cell can be effectively improved.

It should be noted that, the first pole piece 20 is disposed between the first diaphragm 10 and the second diaphragm 30, and the first diaphragm 10 and the second diaphragm 30 are disposed beyond the first pole piece 20, so that the first diaphragm 10 and the second diaphragm 30 form reliable protection for the first pole piece 20, the first diaphragm 10 and the second diaphragm 30 are bonded, delamination problem between the first diaphragm 10 and the second diaphragm 30 can be reduced, and insulation protection capability of the first diaphragm 10 and the second diaphragm 30 for the first pole piece 20 can be improved.

The first diaphragm 10 is bonded with the first pole piece 20, the peeling strength between the first diaphragm 10 and the first pole piece 20 is 5N/m-800N/m, reliable connection between the first diaphragm 10 and the first pole piece 20 can be ensured, and the expansion of the first pole piece 20 can be prevented from being influenced due to the fact that the bonding strength between the first diaphragm 10 and the first pole piece 20 is too high. The excessively high peel strength between the first diaphragm 10 and the first pole piece 20 may cause the risk of material dropping caused by the stress concentration of the first pole piece 20 due to difficult expansion of the first pole piece 20 during the charge and discharge process, while the excessively low peel strength between the first diaphragm 10 and the first pole piece 20 may cause delamination between the first diaphragm 10 and the first pole piece 20, resulting in wrinkling of the first diaphragm 10 and the risk of lithium precipitation.

The first membrane 10 and the second membrane 30 are bonded to form a package for the first pole piece 20, at this time, the first membrane 10, the first pole piece 20 and the second membrane 30 form a whole, and like the first pole piece 20 is installed in the first membrane 10 and the second membrane 30, the first membrane 10 and the second membrane 30 do not necessarily ensure good air tightness, that is, the first membrane 10 and the second membrane 30 are not necessarily in a completely airtight state to the first pole piece 20, and a certain gap may be formed between the connecting edges of the first membrane 10 and the second membrane 30.

The peel strength between the first separator 10 and the first pole piece 20 may be 5N/m, 10N/m, 15N/m, 20N/m, 25N/m, 30N/m, 35N/m, 40N/m, 50N/m, 60N/m, 70N/m, 80N/m, 90N/m, 100N/m, 115N/m, 130N/m, 140N/m, 150N/m, 160N/m, 170N/m, 180N/m, 190N/m, 200N/m, 215N/m, 230N/m, 250N/m, 260N/m, 300N/m, 350N/m, 380N/m, 400N/m, 430N/m, 450N/m, 480N/m, 500N/m, 550N/m, 580N/m, 600N/m, 630N/m, 650N/m, 680N/m, 700N/m, 730N/m, 710N/m, 750N/m, or the like.

The second diaphragm 30 is bonded with the first pole piece 20, the peel strength between the second diaphragm 30 and the first pole piece 20 is 5N/m-800N/m, reliable connection between the second diaphragm 30 and the first pole piece 20 can be ensured, and the expansion of the first pole piece 20 can be prevented from being influenced due to the fact that the bonding strength between the second diaphragm 30 and the first pole piece 20 is too high. The excessively high peel strength between the second diaphragm 30 and the first pole piece 20 may cause the risk of material dropping caused by the stress concentration of the first pole piece 20 due to difficult expansion of the first pole piece 20 during the charge and discharge process, while the excessively low peel strength between the second diaphragm 30 and the first pole piece 20 may cause delamination between the second diaphragm 30 and the first pole piece 20, resulting in wrinkling of the second diaphragm 30 and the risk of lithium precipitation.

The peel strength between the second separator 30 and the first pole piece 20 may be 5N/m, 10N/m, 15N/m, 20N/m, 25N/m, 30N/m, 35N/m, 40N/m, 50N/m, 60N/m, 70N/m, 80N/m, 90N/m, 100N/m, 115N/m, 130N/m, 140N/m, 150N/m, 160N/m, 170N/m, 180N/m, 190N/m, 200N/m, 215N/m, 230N/m, 250N/m, 260N/m, 300N/m, 350N/m, 380N/m, 400N/m, 430N/m, 450N/m, 480N/m, 500N/m, 550N/m, 580N/m, 600N/m, 630N/m, 650N/m, 680N/m, 700N/m, 730N/m, 710N/m, 750N/m, or the like.

In one embodiment, as shown in fig. 4 to 7, the battery cell further includes a first tab 40, where the first tab 40 extends from one end of the first pole piece 20; the first diaphragm 10 covers at least a portion of the first tab 40, and the second diaphragm 30 covers at least a portion of the first tab 40, so that the first diaphragm 10 and the second diaphragm 30 can also form effective protection for the first tab 40, and the first tab 40 and the second tab 50 are prevented from forming erroneous contact, so that the safety performance of the battery cell can be improved to a certain extent.

The first and second diaphragms 10 and 30 are each disposed beyond the first pole piece 20, thereby allowing the first and second diaphragms 10 and 30 to cover portions of the first tab 40.

The first pole piece 20 includes an active material layer, the first tab 40 does not include an active material layer, and the first tab 40 is a metal foil.

In one embodiment, the arc transition between the first tab 40 and the first pole piece 20, that is, at least one end of the first tab 40 connected with the first pole piece 20 is provided with an arc transition connection portion, so that tight adhesion between the first diaphragm 10 and the second diaphragm 30 can be facilitated, the difficulty of right-angle sealing is avoided, stress concentration between the first tab 40 and the first pole piece 20 can be avoided, and structural strength between the first tab 40 and the first pole piece 20 can be improved to a certain extent.

The first tab 40 may be a first rectangular body, the first pole piece 20 may be a second rectangular body, and the first tab 40 and the first pole piece 20 may be in arc transition, so that the first diaphragm 10 and the second diaphragm 30 beyond the first pole piece 20 may form reliable adhesion, and sealing capability of the first diaphragm 10 and the second diaphragm 30 is improved.

Referring to fig. 7, the first tab 40 and the first pole piece 20 may have arc transition portions formed at opposite sides of the first tab 40 connected with the first pole piece 20, so that connection stability between the first tab 40 and the first pole piece 20 may be improved.

In one embodiment, the first diaphragm 10 and the second diaphragm 30 each comprise a rectangular structure, and the four ends of the first diaphragm 10 and the four ends of the second diaphragm 30 are disposed beyond the first pole piece 20, so that the connected first diaphragm 10 and second diaphragm 30 can form reliable protection for the first pole piece 20, and seal protection for the first pole piece 20 can also be formed when the first diaphragm 10 and the second diaphragm 30 are in seal connection.

As shown in connection with fig. 4 and 6, the first diaphragm 10 may include a first rectangular structure covering the first pole piece 20 and a second rectangular structure covering the first pole tab 40.

As shown in connection with fig. 6, the second diaphragm 30 may also include a similar first rectangular structure that covers the first pole piece 20 and a second rectangular structure that covers the first pole tab 40.

In one embodiment, at least one of the four ends of the first diaphragm 10 and the four ends of the second diaphragm 30 are disposed opposite and adhesively connected to ensure the sealing protection of the first diaphragm 10 and the second diaphragm 30 from the first pole piece 20.

In one embodiment, the four ends of the first diaphragm 10 and the four ends of the second diaphragm 30 are bonded, so that not only can the connection strength of the first diaphragm 10 and the second diaphragm 30 be ensured, but also the problem that the first diaphragm 10 and the second diaphragm 30 are separated by mistake can be avoided, and the first diaphragm 10 and the second diaphragm 30 can form sealing protection for the first pole piece 20.

In one embodiment, at least one of the first membrane 10 and the second membrane 30 includes an adhesive layer, where the thickness of the adhesive layer is 0.1 μm-2 μm, and on the basis that the adhesive layer ensures reliable connection between the first membrane 10 and the second membrane 30, it is also possible to avoid affecting the lithium ion transmission rate slower and affecting the charge and discharge rate of the battery cell.

When the thickness of the adhesive layer is thicker, the lithium ion transmission rate may be slower, and the charge and discharge rate of the battery cell is affected, and when the thickness of the adhesive layer is thinner, the adhesive strength between the first diaphragm 10 and the second diaphragm 30 is weaker, and the phenomena such as wrinkling of the first diaphragm 10 and the second diaphragm 30 exist.

The first diaphragm 10 may include an adhesive layer, and one side of the first diaphragm 10 may include an adhesive layer. The second diaphragm 30 may include an adhesive layer, and one side of the second diaphragm 30 may include an adhesive layer.

The thickness of the adhesive layer may be 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, 1.6 μm, 1.7 μm, 1.8 μm, 1.9 μm or 2 μm, etc.

In one embodiment, both opposing surfaces of the first membrane 10 include an adhesive layer, which may enhance the connection capability of the first membrane 10 and may also allow the adhesive layer to increase the structural strength of the first membrane 10.

In one embodiment, both opposing surfaces of the second membrane 30 include an adhesive layer, which may enhance the connection capability of the second membrane 30 and may also allow the adhesive layer to increase the structural strength of the first membrane 10.

In one embodiment, the opposing surfaces of the first membrane 10 each comprise an adhesive layer, and the opposing surfaces of the second membrane 30 each comprise an adhesive layer.

In one embodiment, both opposing surfaces of the first membrane 10 include an adhesive layer, and one surface of the second membrane 30 includes an adhesive layer.

In one embodiment, one surface of the first membrane 10 includes an adhesive layer and the opposite surfaces of the second membrane 30 each include an adhesive layer.

In one embodiment, the thickness of the first pole piece 20 is 50 μm-180 μm, so that the capacity of the battery cell can be ensured, and the excessive thickness of the first pole piece 20 can be avoided, and in the sealing process of the first diaphragm 10 and the second diaphragm 30, the first diaphragm 10 and the second diaphragm 30 are affected by the thickness of the first pole piece 20 due to the excessive thickness of the first pole piece 20, and more bubbles are generated due to the partial weak sealing, so that the first diaphragm 10 and the second diaphragm 30 have the risk of partial wrinkling.

The thickness of the first pole piece 20 may be 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, 105 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 175 μm or 180 μm, etc.

The materials of the first separator 10 and the second separator 30 may be identical, and for example, the materials of the first separator 10 and the second separator 30 may be at least one of polyethylene, polypropylene, polyethylene terephthalate, and the like. The first separator 10 and the second separator 30 may be a single layer structure or a multi-layer composite structure of a plurality of mixed types.

The first separator 10 and the second separator 30 may include a ceramic coating, for example, nano-sized inorganic particles are provided in the ceramic coating, and the inorganic ceramic particles may be selected from, but not limited to, at least one of hydrated alumina (boehmite), alumina, silica, titania, ceria, calcium carbonate, calcium oxide, zinc oxide, magnesia, cerium titanate, calcium titanate, barium sulfate, lithium phosphate, or lithium titanium phosphate.

The adhesive layer may include at least one of polyolefin, epoxy, silicone, or acrylate.

The adhesive layer may include a homopolymer or copolymer formed from polymer monomers including at least one of vinylidene fluoride, hexafluoropropylene, acrylic acid, acrylate, butadiene, styrene, acrylonitrile, ethylene, chlorostyrene, fluorostyrene, or propylene.

The adhesive layer may further include a secondary binder including at least one of homo-or copolymers of ethyl acrylate, butyl acrylate, ethyl methacrylate, styrene, chlorostyrene, fluorostyrene, methylstyrene, acrylic acid, methacrylic acid, maleic acid, acrylonitrile, and butadiene, and a binder.

The adhesive layer may also contain a thickener and a wetting agent. The thickener functions to increase slurry stability and prevent slurry settling. The wetting agent has the function of reducing the surface energy of the slurry and preventing coating from coating missing. The thickener may be sodium carboxymethyl cellulose. The wetting agent comprises at least one of dimethyl siloxane, polyethylene oxide, oxyethylenealkyl phenol ether, polyoxyethylene fatty alcohol ether, polyoxyethylene polyoxypropylene block copolymer or dioctyl sodium sulfosuccinate.

For example, the first separator 10 and the adhesive layer may be molded, and the second separator 30 and the adhesive layer may be molded. Specifically, a polyethylene film is selected as a separator substrate, a ceramic coating layer having a certain thickness is coated on the surface of the separator substrate, and the material of the ceramic coating layer may include boehmite, and a slurry containing an acrylic copolymer, water, polyvinylidene fluoride (PVDF) and sodium carboxymethyl cellulose (CMC) as a thickener is uniformly coated on the ceramic separator having a certain thickness, to thereby form a first separator 10 having an adhesive layer, and a second separator 30 having an adhesive layer.

In one embodiment, as shown in fig. 5 and 6, the battery cell further includes a second pole piece 50, the second pole piece 50 is disposed on a side of the first diaphragm 10 facing away from the first pole piece 20, the polarity of the first pole piece 20 is opposite to that of the second pole piece 50, and the first diaphragm 10 forms an insulating isolation between the first pole piece 20 and the second pole piece 50.

Both opposing surfaces of the first diaphragm 10 may include an adhesive layer, so that both the first and second pole pieces 20 and 50 may be reliably adhered to the first diaphragm 10.

In one embodiment, the second pole piece 50 is disposed on a side of the second diaphragm 30 facing away from the first pole piece 20, the polarity of the first pole piece 20 is opposite to that of the second pole piece 50, and the second diaphragm 30 forms an insulating barrier to the first pole piece 20 and the second pole piece 50.

The opposite surfaces of the second separator 30 may each include an adhesive layer, so that the first and second pole pieces 20 and 50 can each be reliably adhered to the second separator 30.

The battery cell includes a first outer end surface and a second outer end surface which are oppositely disposed, at least one layer of the first pole piece 20 is close to the first outer end surface compared with the second pole piece 50, and/or the second outer end surface is disposed, that is, at least one of two opposite large surfaces of the battery cell may be formed by the first membrane 10 or the second membrane 30, and the first membrane 10, the first pole piece 20 and the second membrane 30 may be formed into a whole by thermal compounding, at this time, after the battery cell is formed, no membrane needs to be separately disposed at the outermost side, for example, if the second pole piece 50 is disposed at the outer end, and a membrane needs to be separately disposed, so that the manufacturing efficiency of the battery cell can be effectively improved to a certain extent in this embodiment. In one embodiment, the first diaphragm 10 and the second diaphragm 30 are both disposed beyond the second pole piece 50, and the first diaphragm 10 and the second diaphragm 30 are both disposed beyond the first pole piece 20, so that the first diaphragm 10 and the second diaphragm 30 can reliably form insulation protection for the first pole piece 20 and the second pole piece 50, thereby improving the safety use performance of the battery cell.

As shown in fig. 4 to 6, the second tab 70 may extend from the second pole piece 50, the polarities of the first tab 40 and the second tab 70 are opposite, and the first tab 40 and the second tab 70 may be located on the same side of the battery cell, or the first tab 40 and the second tab 70 may be located on opposite sides of the battery cell, which is not limited herein.

It should be noted that the battery cell may be a laminated battery cell, and the laminated battery cell may include a plurality of stacked portions. The stack portion may include the first electrode sheet 20, the second electrode sheet 50, the first separator 10, and the second separator 30, and a plurality of stacks may be stacked so that a stacked chip type cell may be formed.

Alternatively, the battery cell may be a wound battery cell, and the wound battery cell may include the first electrode sheet 20, the second electrode sheet 50, the first separator 10, and the second separator 30, and the wound battery cell is formed by winding the first electrode sheet 20, the second electrode sheet 50, the first separator 10, and the second separator 30. The wound cells may be used for cylindrical batteries, or alternatively, the wound cells may be used for quadrangular type batteries.

In one embodiment, the battery cell is formed by hot pressing, the first pole piece 20, the second pole piece 50, the first diaphragm 10 and the second diaphragm 30 are heated, the glue layers on the surfaces of the first diaphragm 10 and the second diaphragm 30 are melted, the first pole piece 20 is bonded and sealed by the first diaphragm 10 and the second diaphragm 30, meanwhile, the first pole piece 20 is bonded with the second diaphragm 30, the first diaphragm 10 is tightly attached to the first pole piece 20, the flatness of the surface of the first diaphragm 10 is guaranteed, the flatness of the surface of the second diaphragm 30 is guaranteed by tightly attached to the second diaphragm 30, the first pole piece 20 and the second diaphragm 50 achieve the improvement of the integral strength of the first diaphragm 10 and the second diaphragm 30, the preparation of the hot pressing composite battery cell is achieved, and therefore the battery cell energy density can be guaranteed.

The first diaphragm 10, the first pole piece 20 and the second diaphragm 30 can be independently heated, so that the glue layers on the surfaces of the first diaphragm 10 and the second diaphragm 30 are melted, and the first diaphragm 10 and the second diaphragm 30 bond and seal the first pole piece 20.

When the battery cell is a laminated battery cell, the battery cell can be conveniently subjected to hot-pressing composite molding because the sizes of the first pole piece 20 and the second pole piece 50 can be relatively smaller, namely, the battery cell can adopt a thermal composite lamination mode.

In one embodiment, the first diaphragm 10, the first pole piece 20 and the second diaphragm 30 are formed by heating and packaging, and by heating the first diaphragm 10, the first pole piece 20 and the second diaphragm 30, the glue layers on the surfaces of the first diaphragm 10 and the second diaphragm 30 are melted, so that the first diaphragm 10 and the second diaphragm 30 bond and seal the first pole piece 20, and meanwhile, the first pole piece 20 and the first diaphragm 10 bond and enable the first diaphragm 10 and the second diaphragm 30 to be tightly attached to the first pole piece 20, the flatness of the surfaces of the first diaphragm 10 and the second diaphragm 30 is guaranteed, the whole strength of the first diaphragm 10 and the second diaphragm 30 is improved by the pole pieces, and the preparation of the thermal composite pole piece is realized.

The first diaphragm 10, the first pole piece 20 and the second diaphragm 30 can be independently heated, packaged and formed, and then assembled with the second pole piece 50. The first diaphragm 10, the first pole piece 20 and the second diaphragm 30 may be formed by hot pressing, i.e. after the first diaphragm 10, the first pole piece 20 and the second diaphragm 30 may be independently heated, a certain pressure is applied to ensure the stability of the first diaphragm 10, the first pole piece 20 and the second diaphragm 30.

It should be noted that, the first membrane 10 and the second membrane 30 are bonded to form a seal with the first pole piece 20, and the seal is not necessarily a complete seal, and the first membrane 10, the first pole piece 20, and the second membrane 30 form a whole, so that the first membrane 10 and the second membrane 30 are bonded to form a package with the first pole piece 20.

An embodiment of the utility model also provides a battery, which comprises the battery cell.

The battery cell of the battery of one embodiment of the present utility model includes the first separator 10, the first separator 20 and the second separator 30, the first separator 20 is located between the first separator 10 and the second separator 30, thereby forming insulation protection for the first separator 20, and the first separator 10 and the second separator 30 are both disposed beyond the first separator 20, and the first separator 10 and the second separator 30 are bonded and encapsulate the first separator 20, so that the risk of wrinkling of the first separator 10 and the second separator 30 can be reduced, and reliable insulation protection for the first separator 20 can be formed. Because the first diaphragm 10 is bonded with the first pole piece 20, the peel strength between the first diaphragm 10 and the first pole piece 20 is 5N/m-800N/m, and/or the peel strength between the second diaphragm 30 and the first pole piece 20 is 5N/m-800N/m, on the basis of ensuring that at least one of the first diaphragm 10 and the second diaphragm 30 is reliably connected with the first pole piece 20, the wrinkling risk is further reduced, the first pole piece 20 can be ensured to expand in the charging and discharging process of the battery core, the risk of material dropping caused by stress concentration of the first pole piece 20 is reduced, and therefore the safe service performance of the battery can be effectively improved.

In one embodiment, as shown in fig. 1 to 3, the battery further includes a battery case 60, and the battery cells are disposed in the battery case 60, so that the battery case 60 can form reliable protection for the battery cells.

The first pole piece 20 is a negative pole piece, the battery shell 60 is an aluminum shell, and the negative pole piece is integrally insulated with the battery shell 60 through hot-pressing sealing of the first diaphragm 10 and the second diaphragm 30, so that corrosion of the battery shell 60 is avoided.

Alternatively, the first pole piece 20 is an anode pole piece, the battery shell 60 is a steel shell, and the anode pole piece is integrally insulated from the battery shell 60 by hot-press sealing of the first diaphragm 10 and the second diaphragm 30, so that ions in the electrolyte can be prevented from being embedded into the lattice of the battery shell 60.

The battery may further include a post assembly 80, the post assembly 80 may be disposed on the battery case 60, the post assembly 80 may be two, and the two post assemblies 80 may be electrically connected to the first tab 40 and the second tab 70, respectively.

As shown in connection with fig. 1, two post assemblies 80 may be disposed at opposite ends of the battery case 60.

As shown in connection with fig. 2 and 3, two pole assemblies 80 may be provided on one surface of the battery case 60. As shown in fig. 2, two pole assemblies 80 may be disposed on one large surface of the battery case 60, and as shown in fig. 3, two pole assemblies 80 may be disposed on one small surface of the battery case 60.

In one embodiment, the method for preparing the battery cell may include:

preparation of the first electrode sheet 20, for example, the first electrode sheet 20 is a positive electrode sheet:

mixing the prepared positive electrode active material, a conductive agent acetylene black and a binder PVDF (polyvinylidene fluoride) according to a mass ratio of 96:2:2, adding a solvent NMP (N-methylpyrrolidone), and stirring under the action of a vacuum stirrer until the system is uniform to obtain positive electrode slurry;

and uniformly coating the positive electrode slurry on two surfaces of a positive electrode current collector aluminum foil, airing at room temperature, transferring to an oven for continuous drying, and then carrying out cold pressing and cutting to obtain a positive electrode plate.

Preparation of the second pole piece 50, for example, the second pole piece 50 is a negative pole piece:

mixing graphite as a negative electrode active material or a mixture of graphite and other active materials according to different mass ratios, acetylene black as a conductive agent, CMC (carboxymethyl cellulose) as a thickening agent and SBR (styrene butadiene rubber) as a binder according to a mass ratio of 96.4:1:1.2:1.4, adding deionized water as a solvent, and stirring under the action of a vacuum stirrer until the system is uniform to obtain negative electrode slurry;

and uniformly coating the negative electrode slurry on two surfaces of a negative electrode current collector copper foil, airing at room temperature, transferring to an oven for continuous drying, and then carrying out cold pressing and slitting to obtain a negative electrode plate.

Preparation of electrolyte:

ethylene Carbonate (EC), ethylmethyl carbonate (EMC) and diethyl carbonate (DEC) are mixed according to a volume ratio of 1:1:1 to obtain an organic solvent, and then a fully dried lithium salt LiPF6 (lithium hexafluorophosphate) is dissolved in the mixed organic solvent to prepare an electrolyte with a concentration of 1 mol/L.

Preparation of the first separator 10 and the second separator 30:

a polyethylene film is selected as a diaphragm substrate, a ceramic coating with the thickness of 1.8 mu m is coated on the surface of the diaphragm substrate, the ceramic coating comprises boehmite, a slurry containing acrylic copolymer, water, polyvinylidene fluoride (PVDF) and sodium carboxymethyl cellulose (CMC) with the thickness of 0.1 mu m-2 mu m in the proportion of 2:100:35:0.6 is uniformly coated on the ceramic diaphragm, namely the content of the acrylic copolymer and the PVDF can be relatively large, so that a high adhesive layer is formed on the surfaces of the first diaphragm 10 and the second diaphragm 30.

Preparation of a lithium ion battery:

the diaphragm and the positive electrode plate or the negative electrode plate are subjected to hot-pressing packaging and then are subjected to lamination assembly with the positive electrode plate or the negative electrode plate to form a bare cell, so that the diaphragm is positioned between the positive electrode plate and the negative electrode plate to play a role in isolation;

and placing the bare cell in a battery shell, drying, injecting electrolyte, and performing vacuum packaging, standing, formation, shaping and other procedures to obtain the lithium ion battery.

The method for testing the battery capacity comprises the following steps:

the battery is placed in a constant temperature box at 25 ℃, and after the lithium ion battery is charged to 4.2V at a constant current of 1C by using an arbin battery test cabinet, the constant voltage is charged to 0.05C of cut-off current, then the battery discharge capacity is extracted from a test computer by discharging to 3.0V at a constant current of 1C.

The peel strength test method between the first separator 10 and the first pole piece 20 may refer to GB/T-27922014 (test method of adhesive tape peel strength), and the peel strength test method between the second separator 30 and the first pole piece 20 may refer to GB/T-27922014.

The following table results can be obtained by using the obtained battery and the corresponding test method:

as can be seen from the test results obtained in the above table, the peel strength between the first separator 10 and the first electrode sheet 20 is 5N/m to 800N/m, the thickness of the adhesive layer is 0.1 μm to 2 μm, and the thickness of the first electrode sheet 20 is 50 μm to 180 μm, so that the lithium precipitation condition of the negative electrode sheet can be made relatively weak, and the battery capacity can be kept from being excessively small. In contrast, in comparative examples 1 to 5, in the case where the battery capacity is relatively large, the negative electrode tab lithium-out condition is high, or in the case where the negative electrode tab lithium-out condition is relatively weak, the battery capacity is relatively small.

An embodiment of the present utility model also provides a battery pack including the above-described battery.

The battery pack according to one embodiment of the present utility model includes a battery, the battery cell includes a first separator 10, a first electrode sheet 20, and a second separator 30, the first electrode sheet 20 is positioned between the first separator 10 and the second separator 30, thereby forming insulation protection for the first electrode sheet 20, and the first separator 10 and the second separator 30 are both disposed beyond the first electrode sheet 20, and the first separator 10 and the second separator 30 are bonded and encapsulate the first electrode sheet 20, so that the risk of wrinkling of the first separator 10 and the second separator 30 can be reduced, and reliable insulation protection for the first electrode sheet 20 can be formed. Because the first diaphragm 10 is bonded with the first pole piece 20, the peel strength between the first diaphragm 10 and the first pole piece 20 is 5N/m-800N/m, and/or the peel strength between the second diaphragm 30 and the first pole piece 20 is 5N/m-800N/m, on the basis of ensuring that at least one of the first diaphragm 10 and the second diaphragm 30 is reliably connected with the first pole piece 20, the wrinkling risk is further reduced, the first pole piece 20 can be ensured to expand in the charging and discharging process of the battery core, the risk of material dropping caused by stress concentration of the first pole piece 20 is reduced, and therefore the safe service performance of the battery can be effectively improved.

In one embodiment, the battery pack is a battery module or a battery pack.

The battery module includes a plurality of batteries, and the battery module can also include end plate and curb plate, and end plate and curb plate are used for fixed a plurality of batteries.

It should be noted that, a plurality of batteries may be disposed in the battery case after forming the battery module, and may be fixed by the end plate and the side plate. The plurality of cells may be disposed directly in the cell case, i.e., without grouping the plurality of cells, at which time the end plates and the side plates may be removed.

Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the utility model disclosed herein. This disclosure is intended to cover any variations, uses, or adaptations of the utility model following, in general, the principles of the disclosure and including such departures from the present disclosure as come within known or customary practice within the art to which the disclosure pertains. The specification and example embodiments are to be considered exemplary only, with a true scope and spirit of the disclosure being indicated by the following claims.

It is to be understood that the present disclosure is not limited to the precise arrangements and instrumentalities shown in the drawings, and that various modifications and changes may be effected without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims

1. A cell, comprising:

a first diaphragm (10);

a first pole piece (20);

a second diaphragm (30), the first pole piece (20) is arranged between the first diaphragm (10) and the second diaphragm (30), and the first diaphragm (10) and the second diaphragm (30) are arranged beyond the first pole piece (20) so that the first diaphragm (10) and the second diaphragm (30) are bonded and encapsulate the first pole piece (20);

wherein the first diaphragm (10) and the first pole piece (20) are bonded, the peeling strength between the first diaphragm (10) and the first pole piece (20) is 5N/m-800N/m, and/or the peeling strength between the second diaphragm (30) and the first pole piece (20) is 5N/m-800N/m.

2. The cell of claim 1, further comprising a first tab (40), the first tab (40) extending from one end of the first pole piece (20);

wherein the first diaphragm (10) covers at least part of the first tab (40), and the second diaphragm (30) covers at least part of the first tab (40).

3. The cell of claim 2, wherein at least one end of the first tab (40) connected to the first pole piece (20) is provided with a circular arc transition connection.

4. The cell of claim 1, wherein the first membrane (10) and the second membrane (30) each comprise a rectangular structure, and wherein the four ends of the first membrane (10) and the four ends of the second membrane (30) are each disposed beyond the first pole piece (20).

5. The cell of claim 4, wherein at least one of the four ends of the first membrane (10) and the four ends of the second membrane (30) are disposed opposite and adhesively connected.

6. The cell of any of claims 1 to 5, wherein at least one of the first separator (10) and the second separator (30) comprises an adhesive layer having a thickness of 0.1-2 μιη.

7. The cell according to claim 6, wherein the opposing surfaces of the first separator (10) each comprise the adhesive layer, and/or the opposing surfaces of the second separator (30) each comprise the adhesive layer.

8. The cell according to any one of claims 1 to 5, wherein the thickness of the first pole piece (20) is 50-180 μm.

9. The cell of any one of claims 1 to 5, further comprising a second pole piece (50), the second pole piece (50) being arranged on a side of the first membrane (10) facing away from the first pole piece (20) or the second pole piece (50) being arranged on a side of the second membrane (30) facing away from the first pole piece (20);

wherein the first diaphragm (10) and the second diaphragm (30) are both arranged beyond the second pole piece (50).

10. The cell according to any of claims 1 to 5, characterized in that the cell is a laminated cell and/or the cell is hot-pressed and/or the first membrane (10), the first pole piece (20) and the second membrane (30) are heat-encapsulated.

11. The cell of any one of claims 1 to 5, further comprising a second pole piece (50), the second pole piece (50) being arranged on a side of the first membrane (10) facing away from the first pole piece (20) or the second pole piece (50) being arranged on a side of the second membrane (30) facing away from the first pole piece (20);

wherein the battery cell comprises a first outer end face and a second outer end face which are oppositely arranged, and at least one layer of the first pole piece (20) is close to the first outer end face compared with the second pole piece (50), and/or the second outer end face is arranged.

12. A battery comprising a cell according to any one of claims 1 to 11.

13. The battery according to claim 12, further comprising a battery housing (60), the battery cell being disposed within the battery housing (60);

the first pole piece (20) is a negative pole piece, the battery shell (60) is an aluminum shell, or the first pole piece (20) is a positive pole piece, and the battery shell (60) is a steel shell.