WO2022198610A1

WO2022198610A1 - Electrochemical apparatus and electric device

Info

Publication number: WO2022198610A1
Application number: PCT/CN2021/083143
Authority: WO
Inventors: 侯天昊; 胡乔舒; 盛阳平
Original assignee: 宁德新能源科技有限公司
Priority date: 2021-03-26
Filing date: 2021-03-26
Publication date: 2022-09-29
Also published as: CN114730947A

Abstract

An electrochemical apparatus, comprising a first housing, a second housing, and an electrode assembly. The first housing comprises a first bottom wall and a first side wall which form a first accommodation recess; the second housing comprises a second bottom wall and a second side wall which form a second accommodation recess; the electrode assembly comprises an electrode plate assembly and a tab; the first side wall is partially or completely accommodated in the second accommodation recess; and the electrode plate assembly is partially or completely accommodated in the first accommodation recess, and is located between the first bottom wall and the second bottom wall. An electric device, comprising the electrochemical apparatus. The electrochemical apparatus can improve the volume energy density of the electrochemical apparatus while improving the sealing effect.

Description

Electrochemical devices and electrical equipment

technical field

The present application relates to the field of batteries, in particular to an electrochemical device and electrical equipment.

Background technique

At present, lithium-ion batteries have a wide range of applications in the field of consumer electronics. With the rapid development of mobile electronic devices in recent years, new product forms have emerged, such as wireless Bluetooth headsets, smart watches, and small electronic game consoles. Lithium-ion battery terminals The market presents a demand for miniaturization and high energy density. At present, in the packaging process of soft-pack lithium-ion batteries, the electrode assembly is firstly placed in the punched packing bag pit, and then the unpunched side is folded along the punched side. Top sealing and side sealing are carried out, followed by baking, liquid injection, sealing, standing, forming, degassing bags and secondary sealing to complete the packaging of the soft-pack lithium-ion battery.

The traditional packaging process determines that soft-pack lithium-ion batteries generally have top sealing edges and side sealing edges. The sealing edge has no active material but occupies a certain volume, which will reduce the energy density of the battery, and the smaller the capacity of the electrode assembly, the lower the energy density. many. At the same time, the steps of side sealing and top sealing are the key processes of traditional flexible package packaging. Although the edge folding process can be used to reduce the loss of energy density, the top seal is folded due to the connection between the tab hot-melt layer and the packaging bag hot-melt layer. The process makes the battery at risk of liquid leakage, and the electrode components of different shapes, such as cylindrical and arc-shaped, are difficult to package in soft packages, especially the risk of damage to the sealing edge and liquid leakage.

SUMMARY OF THE INVENTION

In view of this, it is necessary to provide an electrochemical device capable of improving energy density and sealing effect, and an electrical device having the electrochemical device.

An embodiment of the present application provides an electrochemical device, including a first casing, a second casing and an electrode assembly, the first casing includes a first bottom wall and a first side wall, the first bottom wall and all The first side wall forms a first receiving groove, the second casing includes a second bottom wall and a second side wall, the second bottom wall and the second side wall form a second receiving groove, and the electrode assembly includes a pole piece components and tabs. Part or all of the first side wall is accommodated in the second accommodating groove, and part or all of the pole piece assembly is accommodated in the first accommodating groove, and is located between the first bottom wall and the second bottom between the walls.

In some embodiments, the tab includes a connecting portion, a middle portion and an end portion, the connecting portion is used for connecting the pole piece assembly, and the middle portion is located on the first side wall and the second side between the walls, the end portion is located outside the first shell and the second shell.

The above electrochemical device is partially or completely accommodated in the second accommodating groove through the first side wall, and the pole piece assembly is partially or fully accommodated in the first accommodating groove, and is located between the first bottom wall and the second accommodating groove. between the second bottom wall, and then pass through between the first side wall and the second side wall through the pole lug and protrude out of the first shell and the second shell, The traditional top-sealed and side-sealed packaging is avoided, and the volumetric energy density of the electrochemical device is improved while the sealing effect is improved.

Further, in some embodiments, the tab further includes a bent portion, the bent portion is used for connecting the connecting portion and the intermediate portion, and is located between the second bottom wall and the first between the ends of the side walls.

In some embodiments, the ratio L/T of the length L of the tab extending out of the pole piece assembly to the thickness T of the pole piece assembly ranges from 5 to 20, so that the tab can be bent enough angle and close to the first housing.

In some embodiments, the ratio H ₂ /H ₁ of the height H ₂ of the second side wall to the height H ₁ of the pole piece assembly is in the range of 0.1 to 1.5, so as to ensure that the second casing can encapsulate all the The pole piece assembly is not encapsulated by the first casing.

In some embodiments, a ring-shaped sealing area surrounding the pole piece assembly is provided between the first side wall and the second side wall, and the ring-shaped sealing area is used for connecting the first side wall and the second side wall, so as to seal the gap between the first side wall and the second side wall, and can avoid the structure of top sealing edge.

In some embodiments, there are at least two annular sealing areas to ensure the sealing effect between the first side wall and the second side wall.

In some embodiments, the electrochemical device further includes a sealant located between the first sidewall and the second sidewall to seal the first sidewall and the second sidewall Gap between side walls.

In some embodiments, both the first housing and the second housing comprise a film body selected from a single-layer film or a composite film.

In some embodiments, the single-layer film includes a wear-resistant layer, the composite film includes a water-blocking layer and at least two wear-resistant layers, and the water-blocking layer is located between the two wear-resistant layers, thereby blocking External water vapor enters the inside of the pole piece assembly and the electrolyte seeps out of the pole piece assembly. By providing a wear-resistant layer to ensure the basic use requirements of the electrochemical device, the risk of liquid leakage caused by rupture of the casing during use is reduced.

In some embodiments, the film body is a heat shrinkable film, so that the first casing and the second casing can be shrunk after heating to cover the pole piece assembly.

In some embodiments, the first sidewall further includes a metal layer, and the metal layer is located between the two membrane bodies of the first sidewall.

In some embodiments, the second sidewall further includes a metal layer and a polymer layer, the metal layer is located between the film body of the second sidewall and the polymer layer, and the film The body is located inside the second side wall.

In some embodiments, the abrasion resistant layer comprises polyethylene terephthalate, polyimide, polyamide, polyacrylonitrile, polyether, polyphenylene oxide, polymethyl methacrylate, polycarbonate At least one of ester or fluororesin.

In some embodiments, the water blocking layer includes at least one of silicon nitride, silicon oxide, or aluminum oxide.

An embodiment of the present application also provides an electrical device, including the above electrochemical device.

In the present application, by extending the tabs from between the nested side walls of the first casing and the second casing, the sealing effect of the electrochemical device is improved, the risk of liquid leakage is reduced, and the volume of the electrochemical device is increased at the same time. Energy Density.

Description of drawings

FIG. 1 is a schematic structural diagram of an electrochemical device in an embodiment of the present application.

FIG. 2 is a schematic structural diagram of a pole piece assembly installed in a first housing according to an embodiment of the present application.

FIG. 3 is a schematic structural diagram of the first shell in FIG. 2 after heat shrinking.

FIG. 4 is a schematic structural diagram of the tab in FIG. 3 after bending.

FIG. 5 is a schematic structural diagram of the electrode assembly after the tabs are bent and the first casing being loaded into the second casing in FIG. 4 .

FIG. 6 is a schematic diagram of the structure of the electrode assembly after the tabs are bent and the first casing being loaded into the second casing according to another embodiment of the present application.

FIG. 7 is a schematic structural diagram of the electrochemical device in FIG. 1 from another perspective.

FIG. 8 is a side view of the electrochemical device of FIG. 7 .

Description of main component symbols

Electrochemical device 100

The first shell 10

first bottom wall 11

first side wall 12

First Containment Slot 10a

Second shell 20

second bottom wall 21

second side wall 22

Second Containment Slot 20a

Electrode assembly 30

Pole piece assembly 31

Tabs 32

Connection part 32a

Middle part 32b

end 32c

Bending part 32d

Ring seal area 40

Detailed ways

The technical solutions of the present application will be described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all of the embodiments.

It should be noted that when a component is referred to as being "fixed to" another component, it can be directly on the other component or there may also be a centered component. When a component is considered to be "connected" to another component, it may be directly connected to the other component or there may be a co-existence of an intervening component. When a component is considered to be "set on" another component, it may be directly set on the other component or there may be a co-existing centered component. The terms "vertical," "horizontal," "left," "right," and similar expressions are used herein for illustrative purposes only.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs. The terms used herein in the specification of the present application are for the purpose of describing particular embodiments only, and are not intended to limit the present application. As used herein, the term "or/and" includes any and all combinations of one or more of the associated listed items.

Some embodiments of the present application will be described in detail below with reference to the accompanying drawings. The following embodiments and features of the embodiments may be combined with each other without conflict.

Please refer to FIG. 1 , the present application provides an electrochemical device 100 capable of improving energy density and sealing effect. The electrochemical device 100 includes a first casing 10 , a second casing 20 and an electrode assembly 30 . The first housing 10 is generally in a bag-like structure, and includes a first bottom wall 11 and a first side wall 12 . The first side wall 12 is arranged around and is connected to the first bottom wall 11 at one end and is open at the other end, so that the first bottom wall 11 is open. A first receiving groove 10a is formed together with the first side wall 12 . The second housing 20 is roughly in the shape of a bag, and includes a second bottom wall 21 and a second side wall 22 . The second side wall 22 is arranged around and is connected to the second bottom wall 21 at one end and is open at the other end, so that the second bottom wall 21 A second receiving groove 20 a is formed with the second side wall 22 . The electrode assembly 30 includes a connected pole piece assembly 31 and a tab 32, and the tab 32 includes a connecting portion 32a, a middle portion 32b and an end portion 32c. The pole piece assembly 31 is inserted into the first accommodating groove 10a through the open end of the first housing 10, so that part or all of the pole piece assembly 31 is accommodated in the first accommodating groove 10a. The first housing 10 equipped with the pole piece assembly 31 is inserted into the second receiving groove 20a through the open end of the second housing 20, so that part or all of the first side wall 11 is received in the second receiving groove 20a, and the first The opening directions of the casing 10 and the second casing 20 are opposite, so that the pole piece assembly 31 is located between the first bottom wall 11 and the second bottom wall 21 , and the second casing 20 covers the open opening of the first casing 10 . One end to seal the pole piece assembly 31 . The tab 32 is connected to the pole piece assembly 31 through the connecting portion 32a. The intermediate portion 32b is connected to the connecting portion 32a and is located between the first side wall 12 and the second side wall 22 . The end portion 32c is connected to one end of the middle portion 32b away from the connecting portion 32a, and is located outside the first housing 10 and the second housing 20, and is used for connecting external electrical appliances.

Please refer to FIG. 2 and FIG. 3 , the first housing 10 is heat shrinkable, and the volume of the first receiving groove 10a before heat shrinking is slightly larger than the volume of the pole piece assembly 31 so that the pole piece assembly 31 can enter the first receiving groove 10a . One end of the pole piece assembly 31 away from the tab 32 extends into the first receiving groove 10a, so that the tab 32 is placed outside the first receiving groove 10a. After the pole piece assembly 31 is placed in the first receiving groove 10 a, the first casing 10 is heated, so that the first casing 10 is thermally shrunk until it adheres to the surface of the pole piece assembly 31 . In the illustrated embodiment, all the pole piece assemblies 31 are accommodated in the first receiving groove 10a, and the first shell 10 wraps all other surfaces of the pole piece assembly 31 except for the end face near one end of the pole tab 32 after heat shrinking. In other implementations In an example, the pole piece assembly 31 may be partially accommodated in the first accommodating groove 10a.

Please refer to FIG. 4 , the tab 32 further includes a bending portion 32d, and two ends of the bending portion 32d are respectively connected to the middle portion 32b and the connecting portion 32a. After the first housing 10 is thermally shrunk, the part of the pole tab 32 extending out of the pole piece assembly 31 is bent at a certain angle, so that the pole tab 32 extends toward the second side wall 22 and is located between the pole piece assembly 31 and the second bottom wall. The part between 21 is the bending part 32d, and the part connecting the bending part 32d with the pole piece assembly 31 is the connecting part 32a. Next, the part of the tab 32 extending out of the bent portion 32d is bent again to form a certain angle, so that the tab 32 is close to the first side wall 12 , and the part between the first side wall 12 and the second side wall 22 is The portion of the middle portion 32b extending beyond the first side wall 12 is the end portion 32c. In the illustrated embodiment, the pole piece assembly 31 is a rectangular parallelepiped or a cylinder, the bending portion 32d and the connecting portion 32a form a 90-degree angle, the intermediate portion 32b and the bending portion 32d form a 90-degree angle, and the bending portion 32d and the middle portion 32b are straight. In other embodiments, the pole piece assembly 31 can be in other shapes, such as arc shape, the bending portion 32d and the connecting portion 32a can be at other angles, the middle portion 32b and the bending Other angles may be formed between the parts 32d, and the bent part 32d and the middle part 32b may be curved. In one embodiment, the ratio L/T of the length L of the pole tab 32 extending out of the pole piece assembly 31 to the thickness T of the pole piece assembly 31 ranges from 5 to 20, such as 5, 5.5, 6, 10.2, 17, 20, etc. , so as to ensure that the tabs 32 have a sufficient length to bend and extend out of the first casing 10 and the second casing 20 .

Please refer to FIG. 5 and FIG. 1 , the second housing 20 has heat shrinkability, and the volume of the second receiving groove 20a before heat shrinking is slightly larger than that of the pole piece assembly 31 , the first housing 10 after heat shrinking, and the bent The total volume of the pole tabs 32 is so that the first housing 10 with the pole piece assembly 31 installed therein can enter the second receiving groove 20a. After the first casing 10 with the pole piece assembly 31 is placed in the second receiving groove 20 a, the second casing 20 is heated, so that the second casing 20 is thermally shrunk until it fits the outer surface of the first casing 10 . surface. In the illustrated embodiment, the first casing 10 with the pole piece assembly 31 is all accommodated in the second receiving groove 20a, and the second casing 20 wraps the first side wall 12 of the first casing 10 after being heat-shrinked And the end of the pole piece assembly 31 that is not wrapped by the first shell 10, while the second shell 20 is in close contact with the bent portion 32d and the middle portion 32b of the pole ear 32, so that the bent portion 32d is located between the second bottom wall 21 and the middle portion 32b. Between the ends of the first side wall 12, the middle portion 32b is located between the first side wall 12 and the second side wall 22. In other embodiments, the second shell 20 may only wrap a part of the first side wall 12 , and the ratio H ₂ /H ₁ of the height H ₂ of the second side wall 22 to the height H ₁ of the pole piece assembly 31 is in the range of 0.1 to 1.5, so as to ensure that the second side wall 22 has a sufficient height to encapsulate the pole piece assembly 31 For the area not encapsulated by the first housing 10, as shown in FIG. 6, the height H2 of the second side wall 22 in FIG. 6(a) is _1/2 of the height H1 _of the pole piece assembly 31, and FIG. 6(b) The height H ₂ of the second side wall 22 is 1/5 of the height H ₁ of the pole piece assembly 31 , and the end portion 32 c and the middle portion 32 b of the pole tab 32 are bent at 90 degrees to extend out of the second housing 20 .

Please refer to FIG. 7 and FIG. 8 , after the second casing 20 is thermally shrunk, a ring-shaped sealing area 40 surrounding the pole piece assembly 31 is provided between the first side wall 12 and the second side wall 22 . The ring-shaped sealing area 40 is used for The first side wall 12 and the second side wall 22 are connected to seal the gap between the first side wall 12 and the second side wall 22 to improve the sealing effect. In one embodiment, the annular seal region 40 is a welding trace formed by welding the first side wall 12 and the second side wall 22 around the pole piece assembly 31 by a semiconductor laser with a wavelength of 1700 nm, and passes through the first side wall 12 . The heat fusion effect with the second side wall 22 completes the sealing. In the illustrated embodiment, two annular sealing areas 40 are arranged in parallel at intervals to ensure the sealing effect. In other embodiments, there may be other numbers of annular sealing areas 40 , such as one, three or five.

In one embodiment, a sealant is provided between the first side wall 12 and the second side wall 22 to form the annular sealing area 40 , and the sealant is applied between the first side wall 12 and the second side wall 22 , The gap between the first side wall 12 and the second side wall 22 is sealed to improve the sealing effect. In one embodiment, the sealant is preferably an epoxy structural adhesive.

In one embodiment, both the first casing 10 and the second casing 20 include a film body (not shown), and the film body is selected from a single-layer film or a composite film. In one embodiment, the overall thickness of the composite membrane is 20-300 microns.

The monolayer film includes an abrasion resistant layer. The composite membrane includes a water-blocking layer and at least two wear-resistant layers, and the water-blocking layer is located between the two wear-resistant layers. In one embodiment, the wear-resistant layer is a supporting and protective polymer material, including polyethylene terephthalate, polyimide, polyamide, polyacrylonitrile, polyether, polyphenylene ether, polyacrylonitrile, etc. At least one of methyl methacrylate, polycarbonate or fluororesin, preferably polyethylene terephthalate material. The water-blocking layer includes at least one of silicon nitride, silicon oxide or aluminum oxide. The thickness of the water-blocking layer is 10-2000 nanometers, which can block external water vapor from entering the electrochemical device and electrolyte leakage, ensuring the basic electrochemical device. Usage requirements.

In order to enable the first casing 10 and the second casing 20 to be heat shrinkable, the film body is a heat shrinkable film, and in one embodiment, the shrinkage ratio is greater than or equal to 1.05 and less than or equal to 1.7.

The first side wall 12 further includes a metal layer (not shown), and the metal layer is located between the two film bodies of the first side wall 12 .

The second sidewall 22 further includes a metal layer and a polymer layer (not shown). The metal layer is located between the film body of the second sidewall 22 and the polymer layer, and the film body is located inside the second sidewall 22 .

An embodiment of the present application also provides an electrical device (not shown in the figure), where the electrical device includes an electrochemical device 100 .

The above-mentioned electrochemical device 100 is partially or completely accommodated in the second accommodating groove 20a through the first side wall 12, and the pole piece assembly 31 is partially or completely accommodated in the first accommodating groove 10a, and is located on the first bottom wall 11 and the second bottom wall 21, and then pass through between the first side wall 12 and the second side wall 22 through the tabs 32 and extend out of the first shell 10 and the second shell 20, avoiding the traditional top sealing edge and side sealing. The edge sealing package not only improves the sealing effect, but also improves the volume energy density of the electrochemical device.

In addition, those skilled in the art can also make other changes within the spirit of the present application. Of course, these changes made according to the spirit of the present application should all be included in the scope of the disclosure of the present application.

Claims

An electrochemical device, comprising:

a first casing, comprising a first bottom wall and a first side wall, the first bottom wall and the first side wall forming a first receiving groove;

a second casing, comprising a second bottom wall and a second side wall, the second bottom wall and the second side wall forming a second receiving groove; and

Electrode assemblies, including pole piece assemblies and tabs;

Part or all of the first side wall is accommodated in the second accommodating groove, and part or all of the pole piece assembly is accommodated in the first accommodating groove, and is located between the first bottom wall and the second bottom between the walls.
The electrochemical device of claim 1, wherein the electrode tab comprises a connecting portion, a middle portion and an end portion, the connecting portion is used to connect the electrode assembly, and the middle portion is located on the first Between one side wall and the second side wall, the end portion is located outside the first casing and the second casing.
3. The electrochemical device of claim 2, wherein the tab further comprises a bent portion, the bent portion is used for connecting the connecting portion and the intermediate portion, and is located on the second bottom between the wall and the end of the first side wall.
2. The electrochemical device according to claim 2, wherein the ratio L/T of the length L of the tab extending out of the pole piece assembly to the thickness T of the pole piece assembly ranges from 5 to 20.
The electrochemical device according to claim 1, wherein the ratio H 2 /H 1 of the height H 2 of the second sidewall to the height H 1 of the pole piece assembly ranges from 0.1 to 1.5.
The electrochemical device of claim 1, wherein an annular sealing area surrounding the pole piece assembly is provided between the first side wall and the second side wall.
The electrochemical device of claim 6, wherein there are at least two annular seal areas.
6. The electrochemical device of claim 6, wherein the electrochemical device further comprises a sealant located between the first sidewall and the second sidewall.
The electrochemical device according to claim 1, wherein: both the first casing and the second casing comprise a membrane body, and the membrane body is selected from a single-layer membrane or a composite membrane; the single-layer membrane The film includes a wear-resistant layer, the composite film includes a water-blocking layer and at least two wear-resistant layers, and the water-blocking layer is located between the two wear-resistant layers; at least one of the following conditions i) to v) is satisfied By:

i) the film body is a heat shrinkable film;

ii) the first side wall further includes a metal layer, and the metal layer is located between the two membrane bodies of the first side wall;

iii) The second side wall further includes a metal layer and a polymer layer, the metal layer is located between the film body and the polymer layer of the second side wall, and the film body is located in the the inner side of the second side wall;

iv) The wear-resistant layer includes polyethylene terephthalate, polyimide, polyamide, polyacrylonitrile, polyether, polyphenylene ether, polymethyl methacrylate, polycarbonate or fluororesin at least one of;

v) The water blocking layer includes at least one of silicon nitride, silicon oxide or aluminum oxide.
An electrical equipment, characterized by comprising the electrochemical device according to any one of claims 1 to 9.