CN217522128U

CN217522128U - Lithium battery

Info

Publication number: CN217522128U
Application number: CN202221659324.2U
Authority: CN
Inventors: 李慧珍; 周勇; 颜廷露; 李奎
Original assignee: China Lithium Battery Technology Co Ltd
Current assignee: China Lithium Battery Technology Co Ltd
Priority date: 2022-06-30
Filing date: 2022-06-30
Publication date: 2022-09-30
Anticipated expiration: 2032-06-30

Abstract

The utility model discloses a lithium battery, the insulating film of which comprises a fixed part and coating parts, two second coating parts and a third coating part are used on the second body surface of an electric core; in a flattened state of the insulating film, the two third coating portions are located on both sides of the fixing portion in the second direction; each third coating part is positioned between two second coating parts on the same side and is configured to: when the battery cell is coated on the surface of the second body of the battery cell, the third coating part and the two second coating parts on the same side at least cover the first area of the surface of the second body; the first area is a partial area with a first preset size away from the cover plate. This scheme of using, through the setting of third cladding portion two second cladding portions of cooperation homonymy, can cover the first region on electric core second body surface at least, can wholly improve electric core parcel effect, can avoid the electrolyte to flow and corrode the possibility of explosion-proof valve, invert grouped application mode for the battery and provide good technical guarantee.

Description

Lithium battery

Technical Field

The utility model relates to a lithium ion battery technical field, concretely relates to lithium battery.

Background

In order to improve the safety requirement of the electric vehicle, the safety of the electric vehicle can be improved by the inverted arrangement of the battery. A typical lithium battery comprises a cover plate, a pole, a connecting sheet and a battery cell. Wherein, the apron is fixed in electric core top, is fixed with the insulating film bottom the apron, and the parcel portion of this insulating film is from the bottom of apron downwards with electric core parcel to improve electric core production efficiency, avoid utmost point ear to scurry outward and scald the inside unfamiliar problem of electric core simultaneously.

However, in the battery pack mode of the inverted battery, the electrolyte can flow out from the position where the insulating film on the side edge of the cover plate is wrapped, and can flow to the explosion-proof valve to cause corrosion, which affects the safety and reliability of the battery.

In view of the above, it is desirable to optimize the design of the battery cell to avoid the above-mentioned defects.

SUMMERY OF THE UTILITY MODEL

An object of this application is to provide a lithium cell, can avoid electric core to invert the problem that electrolyte flows when in groups through configuration optimization.

The lithium battery cell comprises a cover plate assembly, a battery cell and an insulating film, wherein the insulating film is wrapped on the outer surface of the battery cell, the cover plate assembly comprises a cover plate, a pole column and an explosion-proof valve, the cover plate assembly is connected to the top of the battery cell through a pole lug, the insulating film is fixedly arranged between the cover plate and the battery cell, the insulating film comprises a fixing part and a cladding part, the fixing part is fixedly connected with the inner surface of the cover plate, and the cladding part extends from the fixing part and wraps the surface of the body of the battery cell; the covering part of the insulating film includes: the two first coating parts are adjacent to the two first edges of the fixing part, which are oppositely arranged, so as to respectively coat the two first body surfaces of the battery cell, which are oppositely arranged; the two second coating parts are adjacent to two opposite edges of one first coating part, and the other two second coating parts are adjacent to two opposite edges of the other first coating part so as to respectively coat two opposite second body surfaces of the battery cell; the two third coating parts are adjacent to the two second edges of the fixing part, which are oppositely arranged, so as to respectively coat the two second body surfaces of the battery cell, which are oppositely arranged; in a flattened state of the insulating film, the two first clad portions are located on both sides of the fixing portion in the first direction, and the two third clad portions are located on both sides of the fixing portion in the second direction; each third coating part is positioned between the two second coating parts on the same side and is configured as follows: when the battery core is coated on the surface of a second body of the battery core, the third coating part and the two second coating parts on the same side at least cover a first area of the surface of the second body; the first area is a partial area which is a first preset size away from the cover plate.

Compared with the prior art, the technical scheme has the following advantages: the lithium battery provided by the embodiment of the application, through the third cladding portion set up two second cladding portions of cooperation homonymy, can cover the first region on electric core second body surface at least, and electrolyte can not the demand of overflowing in the electric core when this first region satisfies the electric core and inverts apart from the apron size. So set up, can wholly improve electric core parcel effect, avoid the possibility of the explosion-proof valve of electrolyte corruption that flows, invert into a group's application mode for the battery and provide good technical guarantee. Furthermore, a first through hole is arranged at the position of the fixing part of the insulating film corresponding to the liquid injection hole on the cover plate, the first through hole is sleeved on the liquid injection hole boss on the cover plate, and the first through hole and the liquid injection hole boss are in interference fit; meanwhile, a second through hole is arranged at the position, corresponding to the pole, of the fixing part of the insulating film, the second through hole is sleeved on the pole, and the second through hole and the pole are in interference fit. So set up, through the material characteristics of insulating film material, ensure the good sealed of above-mentioned position department, further prevent that electrolyte from flowing to apron, corruption explosion-proof valve from battery utmost point post, and annotate the liquid hole.

Drawings

FIG. 1 is an exploded view of an assembly of a lithium battery according to an embodiment;

FIG. 2 is a cross-sectional view A-A of FIG. 1;

FIG. 3 is a schematic view showing a flattened state of the cell insulating film shown in FIG. 1;

FIG. 4 is an enlarged view of portion B of FIG. 2;

fig. 5 is an enlarged view of a portion C of fig. 2.

In the figure:

the battery cell 10 and the shell 20;

the cover plate 1, the injection hole 11, the injection hole boss 111, the insulating film 2, the fixing portion 21, the weak portion 211, the first through hole 212, the second through hole 213, the covering portion 22, the first covering portion 221, the second covering portion 222, the third covering portion 223, the pole 3, the cell 4, the holder 5, and the explosion-proof valve 6.

Detailed Description

In order to make the technical solutions of the present invention better understood by those skilled in the art, the present invention will be further described in detail with reference to the accompanying drawings and specific embodiments.

In the related art, in order to improve the production efficiency of the battery cell and prevent the tab from jumping outwards and scalding the diaphragm inside the battery cell, the insulating film is fixed on the inner surface of the cover plate, and the battery cell is wrapped from the side direction of the cover plate. However, in the battery pack mode in which the battery is inverted, the electrolyte may flow out from the insulating film-wrapped position on the side of the cap plate and may flow toward the explosion-proof valve to cause corrosion thereof.

Based on this, this application embodiment provides a lithium cell, and this lithium cell includes apron subassembly, electric core 10 and parcel setting at the insulating film 2 of electric core 10 surface, and the apron subassembly includes apron 1, utmost point post 2 and explosion-proof valve 6, and the apron subassembly passes through utmost point ear connection and sets up at electric core top, and insulating film 2 is fixed to be set up between apron 1 and electric core 10, places in casing 20 after the equipment is accomplished. Referring to fig. 1 and fig. 2, fig. 1 is an exploded view of an assembled lithium battery according to the present embodiment, and fig. 2 is a sectional view taken along line a-a of fig. 1.

As shown in the figure, the outside of the battery cell is wrapped by the insulating film 2 to avoid short circuit caused by direct contact between the battery cell and the metal shell. For example, but not limited to, the insulating film 2 may be made of a mylar film.

The two poles 2 are arranged on the upper surface of the cover plate 1, one pole is a positive pole, and the other pole is a negative pole; and the two polar columns 2 are respectively connected with the positive pole lug and the negative pole lug of the battery cell 4 through connecting sheets. A retainer 5 is arranged between the cover plate 1 and the battery core 4.

Wherein, the insulating film 2 is fixedly connected with the inner surface of the cover plate 1. Referring to fig. 1, fig. 2 and fig. 3 together, fig. 3 is a schematic view illustrating a flattened state of the cell insulating film shown in fig. 1.

The insulating film 2 includes a fixing portion 21 and a covering portion 22, the fixing portion 21 is fixedly connected with the inner surface of the cover plate 2, and the covering portion 22 extends from the fixing portion 21 and covers the surface of the battery cell 4.

As shown in fig. 3, the cladding 22 of the insulating film 2 includes two first cladding portions 221, four second cladding portions 222, and two third cladding portions 223. The first cladding portion 221 and the third cladding portion are directly adjacent to the fixing portion 21.

The two first wrapping portions 221 are adjacent to the two first edges of the fixing portion 21, which are opposite to each other, so as to wrap two first body surfaces a (one first body surface a is shown in the angle of the drawing) of the battery cell 4, which are opposite to each other; two of the four second coating portions 222 are disposed corresponding to one first coating 221 and adjacent to two opposite edges of the first coating portion 221, and the other two of the four second coating portions 222 are disposed corresponding to the other first coating 221 and adjacent to two opposite edges of the first coating portion 221, so as to respectively coat two opposite second body surfaces b (one second body surface b is shown in the angle of the figure) of the battery cell; the two third wrapping portions 223 are adjacent to the two second edges of the fixing portion 21, which are opposite to each other, so as to wrap the two second body surfaces b of the battery cell, which are opposite to each other, respectively; it is understood that for each second body surface of the cell 4, an encapsulation barrier is formed by two second encapsulants 222 and one third encapsulant 223.

In the flattened state of the insulating film, two first wrapping portions 221 are located on both sides of the fixing portion 21 in the first direction X, and two third wrapping portions 223 are located on both sides of the fixing portion 21 in the second direction Y; each third coating 223 is located between two second coatings 222 on the same side and is configured to: when the battery cell 4 is coated on the second body surface, the third coating portion 223 and the two second coating portions 222 on the same side at least cover the first region b1 of the second body surface b; the first area is a partial area having a first predetermined dimension L from the cover plate 1.

Here, the third coating 223 is provided to match the two second coatings 222 on the same side, so that at least the first region b1 of the second body surface b of the battery cell 4 can be covered. Under the application scene of cell inversion, the electrolyte in the cell cannot escape based on the setting of the first preset size L of the first area from the cover plate, and the possibility that the flowing electrolyte corrodes the explosion-proof valve can be avoided. For example, but not limiting of, the first predetermined dimension L may be 0.5cm to 5 cm.

It is to be understood that the first predetermined dimension L is not limited to a particular specific dimension, and that the dimension may be selected in conjunction with the actual product.

In order to improve the anti-leakage effect, at least a part of the third cladding portion 223 overlaps with the two second cladding portions 222 on the same side, and the electrolyte can be further prevented from leaking out by increasing the overlapping area between the cladding portions of the joint portion.

Further, the covering portion 22 of the insulating film 2 further includes two fourth covering portions 224, which are respectively adjacent to edges of the two first covering portions 221 on opposite sides of the fixing portion 21, so as to cover the third body surface c of the battery cell; as further shown in fig. 3, in the flattened state of the insulating film 2, the two fourth cladding portions 224 are respectively located on one side of the corresponding fixing portion 21 in the first direction X.

It should be noted that, in order to comprehensively avoid the short circuit caused by the direct contact between the battery cell and the metal casing. In this embodiment, the third cladding portion 223 and the two second cladding portions 222 on the same side completely cover the second body surface b on the corresponding side, and the two fourth cladding portions 224 completely cover the third body surface c.

In order to reduce the processing cost of the insulating film, the first, second, third, and

third coating portions

221, 222, 223, and 224 of the insulating film 2 are not overlapped in a flattened state, and thus can be formed from the entire film material, and the material yield is relatively high.

In addition, in the present embodiment, a weak portion 211 is provided on the fixing portion 21 of the insulating film 2, and the weak portion 211 is disposed at a position of the fixing portion 21 corresponding to the explosion-proof valve 6 on the cover plate 1. Thus, when the internal pressure of the battery cell is relatively high, the weak portion 211 and the explosion-proof valve 6 can be pushed open together, so as to achieve an explosion-proof pressure relief state.

Here, "weak" means that the strength of the weak portion 211 is lower than the strength of the material of the fixing portion 21 body, and satisfies the strength requirement that the weak portion can be pushed open when the internal pressure is higher.

In a specific application, the thickness of the body of the weak portion 211 is smaller than the thickness of other portions of the fixing portion 21, or the thickness of a part of the body of the weak portion 211 is smaller than the thickness of other portions of the fixing portion 21, that is, a part of the body can be pushed open; alternatively, the body of the weak portion may be formed by an indentation, in other words, the weak portion 211 may be formed by an indentation form, as long as the above-described functional requirements that can be pushed open together with the explosion-proof valve 6 are satisfied.

Based on the structural characteristics of the non-through hole of the weak part 211, the insulation relation between the cover plate 1 and the internal battery core 4 can be established, so that the design of the retainer 5 can be a grid structure at the position opposite to the explosion-proof valve 6, and the internal space occupation is saved.

In addition, as for the liquid injection hole 11 on the lid plate 1, a first through hole 212 is arranged at a position corresponding to the liquid injection hole 11 on the lid plate 1 on the fixing portion 21 of the insulating film 2, and refer to fig. 4, which is an enlarged view of a portion B of fig. 2. As shown in fig. 4, the first through hole 212 is sleeved on the liquid injection hole boss 111 of the cover plate 1, and the two are in interference fit.

In addition, for the two electrode posts 3 penetrating through the cover plate 1, a second through hole 213 is disposed at a position corresponding to the electrode post 3 in the fixing portion 21 of the insulating film 2, please refer to fig. 5 together, which is an enlarged view of the portion C of fig. 2. The second through hole 213 is sleeved on the pole 3, and the two are in interference fit.

So set up, through the material characteristics of insulating film material, ensure the good sealed of above-mentioned position department.

The ordinal numbers "first" and "second" used herein are only used to describe a common functional component or structure in the claims. It is to be understood that the use of the ordinal numbers "first" and "second" does not constitute an understandable limitation on the claimed technical solution.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that it is obvious to those skilled in the art that various modifications and improvements can be made without departing from the principle of the present invention, and these modifications and improvements should also be considered as the protection scope of the present invention.

Claims

1. A lithium battery comprises a cover plate assembly, a battery cell and an insulating film wrapped on the outer surface of the battery cell, wherein the cover plate assembly comprises a cover plate, a pole and an explosion-proof valve, the cover plate assembly is arranged at the top of the battery cell through a pole lug in a connecting manner, the insulating film is fixedly arranged between the cover plate and the battery cell, the insulating film comprises a fixing part and a wrapping part, the fixing part is fixedly connected with the inner surface of the cover plate, and the wrapping part extends from the fixing part and wraps the surface of a body of the battery cell; characterized in that the coating of the insulating film comprises:

the two first coating parts are adjacent to the two first edges of the fixing part, which are oppositely arranged, so as to respectively coat the two first body surfaces of the battery cell, which are oppositely arranged;

the two second coating parts are adjacent to two opposite edges of one first coating part, and the other two second coating parts are adjacent to two opposite edges of the other first coating part so as to respectively coat two opposite second body surfaces of the battery cell;

the two third coating parts are adjacent to the two second edges of the fixing part, which are oppositely arranged, so as to respectively coat the two second body surfaces of the battery cell, which are oppositely arranged;

in a flattened state of the insulating film, the two first clad portions are located on both sides of the fixing portion in the first direction, and the two third clad portions are located on both sides of the fixing portion in the second direction; each third coating part is positioned between the two second coating parts on the same side and is configured as follows: when the battery cell is coated on the surface of a second body of the battery cell, the third coating part and the two second coating parts on the same side at least cover a first area of the surface of the second body;

the first area is a partial area which is a first preset size away from the cover plate.

2. The lithium battery as claimed in claim 1, wherein a first through hole is disposed at a position of the fixing portion corresponding to the liquid injection hole of the cover plate, the first through hole is sleeved on the liquid injection hole boss of the cover plate, and an interference fit is formed between the first through hole and the liquid injection hole boss.

3. The lithium battery as claimed in claim 1 or 2, wherein a second through hole is disposed at a position of the fixing portion corresponding to the pole, the second through hole is sleeved on the pole, and the second through hole and the pole are in interference fit.

4. The lithium battery of claim 1, wherein at least a portion of the third coating portion is superimposed with two of the second coating portions on the same side.

5. The lithium battery as claimed in claim 4, wherein a weak portion is provided at a position of the fixing portion corresponding to the explosion-proof valve on the cap plate.

6. A lithium battery as claimed in claim 5, characterized in that the body thickness of the weakening portion is smaller than the thickness of the rest of the fixing portion, or part of the body thickness of the weakening portion is smaller than the thickness of the rest of the fixing portion, or the body of the weakening portion is formed by indentations.

7. A lithium battery as claimed in claim 1, characterized in that the first predetermined dimension is between 0.5cm and 5 cm.

8. The lithium battery according to any one of claims 4 to 7, wherein the coating of the insulating film further comprises:

the two fourth coating parts are respectively adjacent to the edges of the two first coating parts, which are opposite to the fixing part, so as to coat the third body surface of the battery cell;

in a flattened state of the insulating film, the two fourth clad portions are respectively located on one side of the corresponding fixing portion in the first direction.

9. The lithium battery of claim 8, wherein the third cladding portion and two of the second cladding portions on the same side completely cover the second body surface on the corresponding side, and two of the fourth cladding portions completely cover the third body surface.

10. The lithium battery according to claim 9, wherein the first coating portion, the second coating portion, the third coating portion, and the third coating portion do not overlap in a flattened state of the insulating film.