CN214254549U

CN214254549U - Electrochemical device and electronic device

Info

Publication number: CN214254549U
Application number: CN202022600269.7U
Authority: CN
Inventors: 李锁晨
Original assignee: Ningde Amperex Technology Ltd
Current assignee: Ningde Amperex Technology Ltd
Priority date: 2020-11-11
Filing date: 2020-11-11
Publication date: 2021-09-21
Anticipated expiration: 2030-11-11

Abstract

The present disclosure provides an electrochemical device and an electronic device. The electrochemical device includes an electrode assembly, a case, a cover, an electrolyte, and at least one air bag. The case has an opening, the gas bag is filled with gas, and the gas bag, the electrode assembly and the electrolyte are contained in the case. The cover body is connected to the shell body to seal the opening of the shell body. In the electrochemical device according to the present disclosure, the arrangement of the air bag fills at least a part of the gap between the electrode assembly and the housing, reduces the free electrolyte filled between the electrode assembly and the housing, improves the effective utilization rate of the electrolyte, reduces the overall weight quality of the electrochemical device, and reduces the use of the electrolyte and the material cost.

Description

Electrochemical device and electronic device

Technical Field

The present disclosure relates to the field of communications technologies, and in particular, to an electrochemical device and an electronic device.

Background

The electrolyte inside the electrochemical device comprises effective electrolyte which is immersed into a pole piece of the electrode assembly and a gap between the pole pieces and free electrolyte which is positioned between the electrode assembly and the shell. The increase of the free electrolyte causes a low effective utilization rate of the electrolyte, reduces the energy density of the electrochemical device, and increases the manufacturing cost of the electrochemical device.

SUMMERY OF THE UTILITY MODEL

In view of the problems in the prior art, an object of the present disclosure is to provide an electrochemical device and an electronic device, which can reduce the amount of free electrolyte between an electrode assembly and a case of the electrochemical device, and reduce the overall weight and manufacturing cost of the electrochemical device.

To achieve the above objects, in some embodiments, the present disclosure provides an electrochemical device including an electrode assembly, a case, a cover, an electrolyte, and at least one air bag. The case has an opening, the gas bag is filled with gas, and the gas bag, the electrode assembly and the electrolyte are contained in the case. The cover body is connected to the shell body to seal the opening of the shell body.

In some embodiments, the housing is a metallic material.

In some embodiments, the electrode assembly is in a wound structure.

In some embodiments, the electrode assembly has bent sections at both sides in the length direction, and the air bags are respectively disposed between the bent sections of the electrode assembly and the case; or the air pocket is disposed at a winding center of the electrode assembly.

In some embodiments, a first adhesive is disposed between the air bag and the electrode assembly.

In some embodiments, a second adhesive is disposed between the air bag and the housing.

In some embodiments, the first adhesive member and the second adhesive member are double-sided tape.

In some embodiments, the gas within the gas bag is a dry gas.

In some embodiments, the material of the air bag comprises at least one of polypropylene or polyethylene.

To achieve the above objects, in some embodiments, the present disclosure provides an electronic device including the electrochemical device described above.

The beneficial effects of this disclosure are as follows: in the electrochemical device according to the present disclosure, the arrangement of the air bag fills at least a part of the gap between the electrode assembly and the housing, reduces the free electrolyte filled between the electrode assembly and the housing, improves the effective utilization rate of the electrolyte, reduces the overall quality of the electrochemical device, and simultaneously reduces the use of the electrolyte and the material cost.

Drawings

Fig. 1 is an exploded view of an electrochemical device according to the present disclosure.

Fig. 2 is a top view of fig. 1, with the cover omitted for clarity.

Fig. 3 is a perspective view of the air bag of fig. 1.

Wherein the reference numerals are as follows:

b electrochemical device 32 electrode terminal

1 electrode assembly 4 gas bag

2 longitudinal direction of the housing L

21 width direction of opening W

3 direction of height of cover body H

31 cover body plate

Detailed Description

The accompanying drawings illustrate embodiments of the present disclosure and it is to be understood that the disclosed embodiments are merely examples that can be embodied in various forms, and therefore, specific details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present disclosure.

The present disclosure provides an electronic device comprising an electronic body and at least one electrochemical device B for providing electrical energy to the electronic body. The electronic device may be a consumer electronic (e.g., mobile phone, computer, etc.), an electric vehicle, or an energy storage device.

In some embodiments, electrochemical device B is a lithium ion battery. Preferably, electrochemical device B is a prismatic lithium ion battery.

As shown in fig. 1 to 3, an electrochemical device B of the present disclosure includes an electrode assembly 1, a case 2, a cover 3, an electrolyte, and at least one air bag 4.

The electrode assembly 1 is a core member of the electrochemical device B that realizes the charge and discharge function. The electrode assembly 1 includes a positive electrode plate, a negative electrode plate, and a separator that separates the positive electrode plate from the negative electrode plate. Preferably, the electrode assembly 1 is a winding structure in which a positive electrode tab, a separator, and a negative electrode tab are sequentially laminated and wound in a flat shape. As shown in fig. 1, the electrode assembly 1 is bent at both sides in the length direction L.

In an embodiment, the housing 2 may have a hexahedral shape. The case 2 is formed inside with a receiving cavity to receive the electrode assembly 1, a gas bag 4 described below, and an electrolyte. The case 2 has an opening 21 at one end, and the electrode assembly 1 may be placed into the receiving cavity of the case 2 through the opening 21. The housing 2 may be made of a metal material, and preferably, the housing 2 is made of aluminum, aluminum alloy, or steel. Since the bent section of the electrode assembly 1 has a curved surface and the inner wall of the case 2 corresponding to the bent section of the electrode assembly 1 is a flat surface, a gap may exist between the bent section of the electrode assembly 1 and the inner wall of the case 2.

The electrolyte comprises effective electrolyte and free electrolyte, wherein the effective electrolyte is the electrolyte which is soaked in the pole pieces and filled in gaps between the adjacent pole pieces; the free electrolyte refers to an electrolyte filled in the gap between the electrode assembly 1 and the case 2; the bent section of the electrode assembly 1 cannot be attached to the inner wall of the case 2 with a large gap left therebetween, thereby increasing the amount of free electrolyte. It should be noted that the increase of the free electrolyte will reduce the effective utilization rate of the electrolyte, reduce the weight energy density of the electrochemical device B, and increase the material cost.

Each gas bag 4 is filled with gas, and at least one gas bag 4 is interposed between the electrode assembly 1 and the case 2.

In one embodiment, the air bag 4 is disposed at the winding center of the electrode assembly 1. In one embodiment, the electrode assembly 1 may have a cylindrical winding structure.

The cover 3 is attached to the case 2 to close the opening 21 of the case 2. The lid body 3 includes a lid body plate 31 and an electrode terminal 32, and the lid body plate 31 is coupled to the case 2 and covers the opening 21 of the case 2, thereby sealing the electrode assembly 1 and the at least one gas pouch 4 within the case 2. The cover plate 31 may be a metal plate and is connected to the case 2 by welding or the like. The two electrode terminals 32 are provided on the lid plate 31, and the two electrode terminals 32 are a positive electrode terminal and a negative electrode terminal, respectively. In some embodiments, the positive terminal is electrically connected to the positive pole piece and the negative terminal is electrically connected to the negative pole piece. The cover plate 31 is provided with a pouring hole (not shown) through which the electrolytic solution can enter the case 2 in the pouring process.

In the electrochemical device B according to the present disclosure, at least one gas bag 4 is interposed between the electrode assembly 1 and the case 2, and the gas bag 4 is disposed to fill at least a part of the gap between the electrode assembly 1 and the case 2, so that the amount of free electrolyte filled between the electrode assembly 1 and the case 2 is reduced compared to the case where the gas bag 4 is not disposed, thereby improving the effective utilization rate of the electrolyte, reducing the overall quality of the electrochemical device B, and simultaneously, reducing the use of the electrolyte and reducing the material cost; furthermore, gas generation occurs in the later stage of the use of the electrochemical device B, the pressure inside the sealed shell 2 increases along with the increase of the generated gas, and the expanded gas bag 4 is compressed and releases part of the gas storage space, so that the deformation of the electrochemical device B can be reduced, and the service life of the electrochemical device B can be prolonged.

In one embodiment, the interior of each gas bag 4 is filled with a gas in an amount not greater than 1/60 of the volume of the housing 2. Preferably, the electrochemical device B comprises two gas bags 4, each gas bag 4 being respectively interposed between a corresponding bent section of the electrode assembly 1 and the case 2; each air bag 4 is filled between the bending section of the electrode assembly 1 and the inner wall of the shell 2, can occupy the gap between the bending section of the electrode assembly 1 and the inner wall of the shell 2, can reduce the amount of free electrolyte to a great extent, reduce the use of the electrolyte and reduce the cost of materials; furthermore, the overall mass of the electrochemical device B is reduced. The gas filled in each gas bag 4 is dry gas, namely, the gas becomes dry gas through dehydration and drying treatment, the dry gas represents that the volume content of water vapor is not more than 0.5 percent, the problems of electrolyte chemical reaction and lithium metal reaction caused by the water vapor when the gas leaks due to the accidental breakage of each gas bag 4 can be prevented, and the safety performance of the electrochemical device B is improved. In one embodiment, the material of the air bag 4 includes at least one of polypropylene or polyethylene. The shape of each gas bag 4 (which means the shape of each gas bag 4 after being vacuum-packed in the case 2) matches the gap between the bent section of the electrode assembly 1 and the case 2. Specifically, as shown in fig. 3, each gas bag 4 has a structure including a circular arc contact surface 41 and three side contact surfaces 42, the circular arc contact surface 41 being attached to the bent section of the electrode assembly 1, and the three side contact surfaces 42 being attached to the inner wall of the case 2. Preferably, each gas bag 4 has a size equal to the height of the case 2 in the height direction H, equal to the width of the case 2 in the width direction W, and does not exceed the bent section of the electrode assembly 1 in the length direction L, and this design allows each gas bag 4 to maximally fill the gap between the bent section of the electrode assembly 1 and the inner wall of the case 2, further reducing the free electrolyte in the case 2.

In one embodiment, a first adhesive (not shown) is disposed between the gas pouch 4 and the electrode assembly 1. In one embodiment, the first adhesive member is a double-sided tape. The first adhesive member effectively fixes the airbag 4, and can prevent the airbag 4 from being positionally displaced during the inflation process and the later use process.

In an embodiment, a second adhesive (not shown) is provided between the airbag 4 and the housing 2. In one embodiment, the second adhesive member is a double-sided tape. The second adhesive effectively fixes the gas bag 4 and the electrode assembly 1, and can effectively prevent the gas bag 4 and the electrode assembly 1 from being positionally displaced.

The production steps of the electrochemical device B of the present disclosure are: the electrode assembly 1 and at least one air bag 4 are placed in a case 2, dried, and then injected with an electrolyte under normal pressure, and then subjected to vacuum packaging, standing, formation, shaping, and the like to obtain a final electrochemical device B. It should be added that the injected amount of the electrolyte should not fill the case 2, and in one embodiment, the injected amount of the electrolyte is reduced by 6% compared with the injected amount of the electrolyte without placing the air bag 4, so as to provide an expansion space for the expansion of the air bag 4 during the vacuum packaging process and prevent the electrolyte from leaking out. During the vacuum packaging process, the sealed air bag 4 expands along with the reduction of the pressure, and preferably, the air bag 4 is set to enable the liquid level of the electrolyte after the expansion in the vacuum packaging process to rise to soak the whole electrode assembly 1, so that the electrode assembly 1 can be fully soaked, and the quality of the electrode assembly 1 is ensured.

Claims

1. An electrochemical device comprising an electrode assembly, a housing having an opening, a cover, an electrolyte, and at least one gas pouch, wherein a gas is disposed in the gas pouch, the electrode assembly, and the electrolyte are contained in the housing, and the cover is coupled to the housing to close the opening of the housing.

2. The electrochemical device of claim 1, wherein said housing is a metallic material.

3. The electrochemical device according to claim 1, wherein the electrode assembly has a wound structure.

4. The electrochemical device according to claim 3,

the two sides of the electrode assembly along the length direction are provided with bending sections, and the air bags are respectively arranged between the bending sections of the electrode assembly and the shell; or

The air pocket is disposed at a winding center of the electrode assembly.

5. The electrochemical device according to claim 1, wherein a first adhesive member is disposed between the gas pouch and the electrode assembly.

6. The electrochemical device of claim 5, wherein a second adhesive is disposed between the gas pouch and the housing.

7. The electrochemical device according to claim 6, wherein the first adhesive member and the second adhesive member are double-sided tapes.

8. The electrochemical device of claim 1, wherein the gas within the gas pouch is a dry gas.

9. An electronic device, characterized in that it comprises an electrochemical device according to any one of claims 1 to 8.