CN114284579A

CN114284579A - Anti-deformation stacked battery cell and manufacturing method thereof

Info

Publication number: CN114284579A
Application number: CN202010977414.5A
Authority: CN
Inventors: 张继锋; 徐言慧; 刘淼; 张艳萍; 唐成平
Original assignee: Ray Tech International Ltd
Current assignee: Ray Tech International Ltd
Priority date: 2020-09-17
Filing date: 2020-09-17
Publication date: 2022-04-05

Abstract

The anti-deformation stacked battery cell comprises a battery cell body, a battery cell body and a battery cell, wherein the battery cell body consists of diaphragm bags which are sequentially stacked at intervals and are packaged with packaging electrode plates, and bare electrode plates with different electric polarities from the packaging electrode plates; at least part of the plastic supporting piece which is connected with the membrane bag is arranged between the membrane bags on two sides of at least one bare electrode piece and protrudes out of the edge of the bare electrode piece, and the plastic supporting piece deforms after being heated and diffuses to the periphery so as to fill the space between the membrane bags and protrude out of the edge of the bare electrode piece, so that the filling compaction and deformation resistance of the edge of the membrane bag are realized. The plastic support piece deforms to fill the gap of the diaphragm bag exceeding the electrode plate, and simultaneously plays a role in connecting the diaphragm bag and supporting the diaphragm bag to exceed the gap of the electrode plate. Like this when the in-service use, the shell is arranged in to the electric core body after the shaping, and the impact of plastic membrane deformation to inside electric core can effectively be slowed down to the plastic support piece after the deformation for electric core obtains effectual protection, is unlikely to scrap.

Description

Anti-deformation stacked battery cell and manufacturing method thereof

Technical Field

The invention relates to the technical field of battery cells, in particular to an anti-deformation stacked battery cell and a manufacturing method thereof.

Background

In the field of lithium ion batteries, regardless of the production of soft packages, cylinders or button cells, winding or stacking is often adopted. The battery cell comprises a positive plate, a negative plate and a diaphragm, the size relation of which complies with the increasing rule in sequence, the positive plate, the negative plate and the diaphragm are assembled, fixed and welded with a pole lug and then are placed into an aluminum plastic film shell or a steel shell, and the lithium ion battery cell is formed through subsequent processing.

The positive plate, the negative plate and the diaphragm rule that the size increases in proper order are obeyed in the production of electricity core, are on the one hand in order to satisfy the requirement of just, negative pole capacity ratio, and on the other hand is in order to prevent pole piece off tracking, dislocation reservation error space in the production process, satisfy that the diaphragm wraps up completely and live just, the negative pole wraps up completely and lives anodically. But can produce a problem like this, the part that the diaphragm surpassed the electrode slice in the naked electric core lamination body promptly, head, afterbody or the side of electric core can reserve promptly and have more connection space department, and it is not closely knit to fill, and electric core is out of shape easily when falling or extrusion atress, influences the battery outward appearance, damages the pole piece even, scrapps the battery.

Disclosure of Invention

The invention aims at overcoming the defects and shortcomings and provides a battery cell which is compact in filling at the joint of a positive electrode, a negative electrode and a diaphragm, convenient to form, capable of improving the deformation resistance of the battery cell and capable of preventing the battery cell from falling.

Another object of the present invention is to provide a unique method for manufacturing an electrical core, wherein a hot melt adhesive is adhered to the edge or the frame of a diaphragm bag, so that not only can gaps be filled, but also the diaphragm bag and a pole piece can be better fixed, thereby preventing deviation, reducing thermal shrinkage of the diaphragm bag, solving the problem that the edge of the electrical core is easy to deform when the electrical core falls or is stressed by extrusion, and improving thermal shock and the pass rate of drop tests.

In order to achieve the purpose, the invention adopts the following specific technical scheme:

the anti-deformation stacked battery cell comprises a battery cell body, a battery cell body and a battery cell, wherein the battery cell body consists of diaphragm bags which are sequentially stacked at intervals and are packaged with packaging electrode plates, and bare electrode plates with different electric polarities from the packaging electrode plates; at least part of the plastic supporting piece which is connected with the membrane bag is arranged between the membrane bags on two sides of at least one bare electrode piece and protrudes out of the edge of the bare electrode piece, and the plastic supporting piece deforms after being heated and diffuses to the periphery so as to fill the space between the membrane bags and protrude out of the edge of the bare electrode piece, so that the filling compaction and deformation resistance of the edge of the membrane bag are realized.

The membrane bag is of a bag body structure with edges pressed in advance, electrode plates are arranged in the membrane bag, and then the edges are sealed to obtain a bag. The electrode plate can be a positive plate or a negative plate. Preferably, a positive plate is provided.

Preferably, the moldable support member comprises at least two moldable adhesive layers and a support layer disposed between the moldable adhesive layers.

Preferably, the plastic bonding layer is composed of a hot melt adhesive, and the mode that the hot melt adhesive is heated to melt and deform is favorable for subsequent forming and the forming process is simplified.

Preferably, at least one of said moldable adhesive layers is comprised of a cured hot melt adhesive.

When actually manufacturing the battery core, the normal-temperature bonding layer is bonded with the diaphragm bag, and then the subsequent lamination process is carried out.

The suppression that this patent adopted bonds the deformation layer and comprises triplex, hot melt adhesive layer (sis), PET thin layer, hot melt adhesive layer (sis), and the hot melt adhesive layer curing of one side wherein has viscidity under the normal atmospheric temperature, glues on the diaphragm, normal atmospheric temperature adhesive linkage promptly. The other surface has viscosity when hot pressed and can be bonded with the hot melt adhesive layer on the other adjacent membrane, namely a pressing bonding deformation layer. The middle supporting layer can not melt and deform when being subjected to hot pressing by the PET film layer, has the function of strength supporting and can better resist deformation.

Preferably, the inner edge of the plastic support member at least extends to the outer edge of the bare electrode plate, and the outer edge of the plastic support member at least extends to the outer edge of the diaphragm bag, so that consumables are reduced on the basis of ensuring the support strength to save the cost.

The membrane bag is made of a conventional material with a permeable porous structure on the surface, and the surface of the electrode plate is also made of a material with a permeable porous structure. These permeable porous structures are used to allow the formed cells to be permeated with electrolyte.

Preferably, the flexible support forms a frame structure along a peripheral side edge of the membrane bag.

Preferably, frame structure includes the frame body, the frame body is including the connecting portion that the interval set up in proper order and the spacer that plastic volume surpassed adjacent connecting portion, spacer and connecting portion receive diffusion around the plastic shape diversion simultaneously after the hot pressing and fill protruding bare electrode piece edge between the diaphragm bag, and the spacer diffusion space of big plastic volume surpasss connecting portion.

Preferably, the spacing part is a structure with upper and lower side surfaces parallel to the membrane bags, and the upper and lower side surfaces are well jointed with the membrane bags and uniformly stressed when being pressed.

Preferably, the connecting portion is formed by a flat strip between adjacent spacers.

Preferably, the bare electrode plate is a negative electrode plate, and the packaging electrode plate is a positive electrode plate; the outer edge of the negative plate exceeds the outer edge of the positive plate.

Preferably, the thickness of the plastic support is 0.01-1 mm, and the plastic support is used for forming a proper volume after melting so as to fill the gap between the edges of the membrane bag. The plastic bonding layer is too thin and is not enough to fill and support the gap of the edge of the diaphragm bag after being melted; after the plastic bonding layer is melted, the molding is influenced and the volume of the battery cell is increased.

The manufacturing method of the anti-deformation stacked battery cell comprises the following steps:

s1, superposing: superposing a bare electrode plate, a diaphragm bag packaged with a packaged electrode plate and a plastic support piece, wherein the plastic support piece is positioned between the diaphragm bags and protrudes out of the edge of the bare electrode plate to obtain a basic cell body;

s2, press forming: and hot-pressing the edge of the basic cell body to form the cell body under the action of external force.

Preferably, in the step S2, interval hot pressing is adopted, so that a liquid injection channel is reserved for subsequent liquid injection conveniently.

Preferably, step s3. installing a casing is further included between step s1. and step s 2: and placing the cell body in a shell, and then carrying out integral hot-press molding on the shell and the basic cell body to form the cell body.

Compared with the prior art, the invention has the following beneficial effects:

the plastic bonding layer is arranged between the membrane bags and protrudes out of the edge of the bare electrode plate, the plastic supporting piece is deformed by external force applied by hot pressing, so that gaps of the membrane bags, which exceed the electrode plate, are filled, and the membrane bags are connected. After the plastic supporting piece deforms, external force stops being applied, the existing structure is kept after the plastic supporting piece is cooled, and the effect of supporting the diaphragm bag to exceed the gap of the electrode plate can be achieved. Like this when in-service use, the shell is arranged in to electric core body after the shaping, if the material of shell is softer, receives external force yielding, when taking place this kind of condition, the plastic support piece after the deformation can effectively slow down the impact of shell deformation to inside electric core for electric core obtains effectual protection, is unlikely to scrap.

The battery cell manufactured by the battery cell manufacturing method has the performances of falling resistance, impact resistance and deformation resistance, has better capability of coping with accidents compared with the existing battery cell, and effectively improves the structural strength and the service life of the battery cell.

The invention will be further described with reference to the accompanying drawings.

Drawings

FIG. 1 is a schematic view of the construction of a separator before and after bag making in a preferred embodiment of the present invention.

Fig. 2 is a schematic diagram of a cell disassembly structure in the preferred embodiment of the present invention.

Fig. 3 is a schematic structural diagram of a cell to be pressed in a preferred embodiment of the present invention.

FIG. 4 is a schematic longitudinal cross-sectional view of a moldable adhesive layer in accordance with a preferred embodiment of the present invention.

FIG. 5 is a schematic view of a plastic support according to a preferred embodiment of the present invention.

Description of reference numerals:

1 electrode slice, 11 naked electrode slice, 12 encapsulation electrode slice, 2 diaphragm bags, 3 electricity core bodies, 4 plastic support piece, 41 normal atmospheric temperature adhesive linkage, 42 supporting layer, 43 plastic adhesive linkage, 6 frame bodies, 61 connecting portion, 62 intervals.

Detailed Description

The present invention is further explained and illustrated by the following embodiments, which should be understood to make the technical solution of the present invention clearer and easier to understand, and not to limit the scope of the claims.

Example 1

As shown in fig. 1 to 3, the deformation-resistant stacked cell of the invention is manufactured by pressing the edges of the bag structure in advance to form a membrane bag 2, and electrode sheets 12 are installed inside the membrane bag 2. The electrode sheet 12 may be a positive electrode sheet or a negative electrode sheet. Preferably, a positive plate is provided. The membrane bag 2 is made of a conventional material with a permeable porous structure on the surface, and the electrode plate 1 is also made of a material with a permeable porous structure on the surface. These permeable porous structures are used to allow the formed cells to be permeated with electrolyte.

The battery cell comprises a battery cell body, wherein the battery cell body comprises a plurality of electrode plates 1, and each electrode plate 1 comprises a naked electrode plate 11 and an encapsulated electrode plate 12. The novel membrane bag comprises a plurality of bare electrode plates 11, a membrane bag 2 which is arranged between the bare electrode plates 11 and internally sealed with an outer edge of a packaging electrode plate 12 exceeding the bare electrode plates 11, the bare electrode plates 11 are connected with the edge of the membrane bag 2 through a plastic supporting piece 4, and the plastic supporting piece 4 is deformed and adhered in the compression molding process and fills the gap between the adjacent membrane bags 2 exceeding the bare electrode plates 11 to fulfill the aim of filling, compacting and preventing deformation. The bare electrode plate 11 is a negative electrode plate, and the packaging electrode plate 12 is a positive electrode plate; the outer edge of the negative plate exceeds the outer edge of the positive plate.

In a preferred embodiment, the thickness of the moldable support 4 is 0.01 to 1mm for forming a suitable volume after melting to fill the edge gap of the membrane bag 2. The plastic bonding layer is too thin and is not enough to fill and support the edge gap of the diaphragm bag after being melted; the plastic bonding layer is too thick, and the molding is influenced and the volume of the battery cell is increased after the plastic bonding layer is melted.

In a preferred embodiment, as shown in fig. 4, the moldable support member 4 comprises at least two moldable adhesive layers 43, and a support layer 42 disposed between the moldable adhesive layers 43, wherein the support layer 42 can improve the support strength for the purpose of deformation resistance. The plastic bonding layer 43 is composed of hot melt adhesive, and the mode that the hot melt adhesive is heated to melt and deform is favorable for subsequent forming and simplifies the forming process. At least one of the moldable adhesive layers 43 is comprised of a cured hot melt adhesive. The moldable adhesive layer composed of the cured sol is a normal temperature adhesive layer 41.

When actually manufacturing the battery core, the normal temperature adhesive layer 41 is adhered to the diaphragm bag 2, and then the subsequent lamination process is performed. The non-cured moldable adhesive layers 43 face each other during lamination and deform and adhere to each other under the influence of external forces.

The pressing bonding deformation layer adopted by the invention comprises three parts, namely a cured hot melt adhesive layer (sis), a PET film layer and a hot melt adhesive layer (sis) which can deform and adhere after pressing, wherein the hot melt adhesive layer on one surface is cured, has viscosity at normal temperature and is bonded on a diaphragm, namely the normal temperature bonding layer 41. The other side is sticky when hot pressed and is bonded with the hot melt adhesive layer on the other side of the adjacent diaphragm, namely, the bonding deformation layer 43 is pressed and bonded. The middle supporting layer 42 is a PET film layer which can not be melted and deformed during hot pressing, has the function of strength supporting and can better resist deformation.

As shown in fig. 5, in a preferred embodiment, the frame structure includes a frame body 6, the frame body 6 includes connecting portions 61 arranged at intervals in sequence, and a spacing portion 62 having a plastic volume exceeding that of the adjacent connecting portion 61, the spacing portion 62 and the connecting portion 61 are subjected to hot pressing, and simultaneously the plastic shape is changed to be diffused and filled around to protrude the edge of the bare electrode sheet 11 between the membrane bags 2, and the diffusion space of the spacing portion 62 having a large plastic volume exceeds that of the connecting portion 61. For better stress, the spacing part 62 is formed by a structure that the upper side and the lower side of the diaphragm bag 2 are parallel to the diaphragm bag 2, and the upper side and the lower side are well jointed with the diaphragm bag 2 and uniformly stressed when being pressed. The connecting portion 61 may be formed as a flat strip between adjacent spacers 62.

In a preferred embodiment, the inner edge of the plastic support 4 extends to the outer edge of the bare electrode plate 11, and the outer edge of the plastic support 4 extends to the outer edge of the membrane bag 2, so that the consumption of materials is reduced on the basis of ensuring the supporting strength to realize cost saving.

Example 2

As shown in fig. 2, in the method for manufacturing a deformation-resistant stacked electrical core according to the present invention, a positive plate 11 (or a negative plate 12) is placed between two separator bags 2, and the edges of the separator bags 2 are pressed to form a separator bag with the same shape and wrapped with the positive plate 11 (or the negative plate 12), wherein the separator bag 2 portion of the separator bag is slightly larger than the positive plate 11 (or the negative plate 12). On this basis, prepare one by curing hot melt adhesive (normal atmospheric temperature adhesive linkage 41), PET film (supporting layer 42) and just can take place after the suppression and the frame 4 that the hot melt adhesive layer (plastic adhesive linkage 43) of deformation and adhesion are constituteed, the internal diameter of frame 4 is the same with the length of electrode slice 11, the external diameter is the same with the length of diaphragm bag 2, then paste the one side 41 that has the stickness under the normal atmospheric temperature of hot melt

adhesive frame

4 and 2 two sides outline border of diaphragm bag, form the pole piece bag of taking the hot melt adhesive. After the lamination is completed, the battery core body is hot-pressed, the hot melt adhesive surface 42 is heated and melted to have viscosity, the edges of the adjacent diaphragm bags 2 are stuck, the battery core body is directly fixed, and gaps between the layers of the diaphragm bags 2 are filled. This reduces thermal shrinkage of the membrane bag 2 when subjected to thermal shock. If direct hot pressing behind the lamination, can save the original lamination back and need to make whole lamination body outside fixed process step of rubberizing paper, make whole electric core more pleasing to the eye, also practice thrift cost and time. In order to ensure that subsequent liquid injection is not affected, the peripheral frame 4 is not necessarily sealed by hot pressing in a hot pressing area, the peripheral frame 4 can be subjected to interval hot pressing, and only the frames 4 at the head and the tail of the cell body or the frames 4 at the left and the right can be subjected to hot pressing. Furthermore, it is not necessary to perform hot pressing after the lamination step, but it is also possible to perform hot pressing simultaneously with the casing, for example an aluminum-plastic film, during the high-temperature shaping of the subsequent production of the cell. The hot melt adhesive on the electric core body outer lane diaphragm bag 2 can glue the shell inner wall when high temperature integer hot pressing, fixed electric core body that can be better.

While the present invention has been described by way of examples, and not by way of limitation, other variations of the disclosed embodiments, as would be readily apparent to one of skill in the art, are intended to be within the scope of the present invention, as defined by the claims.

Claims

1. The utility model provides an anti deformation heap electricity core which characterized in that: the battery cell comprises a battery cell body (3) which is formed by sequentially stacking diaphragm bags (2) at intervals and packaging electrode plates (12) and bare electrode plates (11) with different electric polarities from the packaging electrode plates (12);

at least one plastic support piece (4) connected with the membrane bags (2) is arranged at least partially and protruding out of the edge of the bare electrode piece (11) between the membrane bags (2) on two sides of at least one bare electrode piece (11), and the plastic support piece (4) deforms after being heated and diffuses to the periphery to fill the space between the membrane bags (2) and protrude out of the edge of the bare electrode piece (11), so that the edge of the membrane bag (2) is filled, compacted and deformation-resistant.

2. The deformation-resistant stacked cell of claim 1, wherein: the plastic supporting piece (4) comprises at least two layers of plastic bonding layers (43) and a supporting layer (42) arranged between the plastic bonding layers (43).

3. The deformation-resistant stacked cell of claim 2, wherein: the plastic bonding layer (43) is composed of hot melt adhesive, and the mode of the hot melt adhesive that is heated to melt and deform is favorable for subsequent molding and simplifies the molding process.

4. The deformation-resistant stacked cell of claim 3, wherein: at least one of said moldable adhesive layers (43) is composed of a cured hot melt adhesive.

5. The deformation-resistant stacked cell of claim 1, wherein: the plastic support (4) forms a frame structure along the peripheral side edge of the diaphragm bag (2).

6. The deformation-resistant stacked cell of claim 5, wherein: the frame structure comprises a frame body (6), the frame body (6) comprises connecting parts (61) which are sequentially arranged at intervals and a spacing part (62) of which the plastic volume exceeds the adjacent connecting part (61), the spacing part (62) and the connecting parts (61) are subjected to hot pressing and simultaneously plastically deformed to the periphery to be diffused and filled in the membrane bags (2) and protrude out of the edge of the bare electrode plate (11), and the diffusion space of the spacing part (62) with large plastic volume exceeds the connecting part (61); preferably, the spacing part (62) is formed by a structure that the upper side surface and the lower side surface are parallel to the membrane bag (2) between the membrane bags (2), and the upper side surface and the lower side surface are well jointed with the membrane bags (2) and uniformly stressed when being pressed; preferably, the connecting portion (61) is formed as a flat strip between adjacent spacers (62).

7. The deformation-resistant stacked cell of claim 1, wherein: the thickness of the plastic support (4) is 0.01-1 mm, and the plastic support is used for forming a proper volume after deformation so as to fill the edge gap of the diaphragm bag (2).

8. A method of making a deformation resistant stacked cell according to any of claims 1 to 7, wherein: the method comprises the following steps:

s1, superposing: superposing a bare electrode plate (11), a diaphragm bag (2) packaged with a packaging electrode plate (12) and a plastic support piece (4) so that the plastic support piece (4) is positioned between the diaphragm bags (2) and protrudes out of the edge of the bare electrode plate (11) to obtain a basic cell body;

9. The method of making a deformation-resistant stacked electrical core of claim 8, wherein: and S2, adopting interval hot pressing for facilitating subsequent liquid injection and reserving a liquid injection channel.

10. The method of making a deformation-resistant stacked electrical core of claim 8, wherein: step S3. install the shell still include between step S1, S2: and placing the cell body in a plastic shell, and then performing integral hot-press molding on the plastic shell and the basic cell body to form the cell body.