CN210805829U

CN210805829U - Secondary battery, battery module, and device

Info

Publication number: CN210805829U
Application number: CN201922068314.6U
Authority: CN
Inventors: 杨凯
Original assignee: Contemporary Amperex Technology Co Ltd
Current assignee: Contemporary Amperex Technology Co Ltd
Priority date: 2019-11-26
Filing date: 2019-11-26
Publication date: 2020-06-19
Anticipated expiration: 2029-11-26

Abstract

The utility model provides a secondary battery, battery module and device. The secondary battery includes an electrode assembly, a packaging bag, an electrode lead, and an insulating member. The electrode assembly is accommodated in the packaging bag, the edge of the packaging bag is provided with a sealing part, and the electrode lead is connected to the electrode assembly and penetrates through the sealing part. The insulator surrounds the outside of the electrode lead and is connected to the sealing part, and the insulator separates the sealing part from the electrode lead. The electrode lead has a fusing part, and the insulating member covers and is connected to the fusing part.

Description

Secondary battery, battery module, and device

Technical Field

The utility model relates to a battery field especially relates to a secondary battery, battery module and device.

Background

Secondary batteries are increasingly widely used as representative energy storage devices in new energy fields, in the fields of mobile electronic devices, electric vehicles and the like.

During the high-speed driving process of the electric automobile, the battery is subjected to severe working conditions, which provides great challenges for the safety performance of the battery. For example, the high-frequency vibration and impact of the electric vehicle may cause the risk of short circuit of the battery, and especially when the electric vehicle has a traffic accident such as collision, the battery is strongly squeezed, and the short circuit is easily caused. Once the battery is short-circuited, a great current is generated, the heat generated by the battery is rapidly increased, and the thermal runaway inside the battery is easily caused, so that the safety accidents of combustion, even explosion and the like of the battery occur.

SUMMERY OF THE UTILITY MODEL

In view of the problems existing in the background art, the present invention is directed to a secondary battery, a battery module and a device, which can cut off a circuit in time when the secondary battery is short-circuited, thereby improving safety performance.

In order to accomplish the above object, the present invention provides a secondary battery including an electrode assembly, a pouch, an electrode lead, and an insulator. The electrode assembly is accommodated in the packaging bag, the edge of the packaging bag is provided with a sealing part, and the electrode lead is connected to the electrode assembly and penetrates through the sealing part. The insulator surrounds the outside of the electrode lead and is connected to the sealing part, and the insulator separates the sealing part from the electrode lead. The electrode lead has a fusing part, and the insulating member covers and is connected to the fusing part.

The electrode lead is provided with fusing hole, follows the width direction of electrode lead, fusing hole with fusing portion sets up side by side, just fusing portion's size is less than the size of other parts of electrode lead. The insulator has a cylindrical portion extending into the fuse hole.

The fuse hole is a plurality of, the cylindricality portion is a plurality of, each fuse hole with each cylindricality portion corresponds the setting.

The insulating member further has a first insulating portion and a second insulating portion, the first insulating portion and the second insulating portion being respectively located at both sides of the electrode lead in the thickness direction and covering the fusing portion, and the cylindrical portion connecting the first insulating portion and the second insulating portion.

The electrode lead further includes an inner extension and an outer extension, and the fusing part is connected between the inner extension and the outer extension. The one end of keeping away from of interior extension the fusing portion is located the inside of wrapping bag, the one end of keeping away from of outer extension the fusing portion is located the outside of wrapping bag. The first and second insulating portions cover a portion of the inner extension portion, and the first and second insulating portions cover a portion of the outer extension portion.

The sealing portion is welded to at least the first insulating portion and a portion of the second insulating portion covering the fusing portion.

The ratio of the area of the cross section of the fusing part to the area of the cross section of the other part of the electrode lead is 0.3-0.8. The cross section is a cross section perpendicular to a length direction of the electrode lead.

The packaging bag comprises two layers of packaging films, the electrode assembly is located between the two layers of packaging films, and the two layers of packaging films are connected at the edge and form the sealing part. Each packaging film includes a protective layer, a metal layer, and a connection layer provided on a surface of the metal layer facing the electrode assembly, the protective layer being provided on a surface of the metal layer remote from the electrode assembly. The electrode lead penetrates through the two packaging films.

In order to achieve the above object, the present invention also provides a battery module including a plurality of the secondary batteries.

In order to achieve the above object, the present invention also provides a device, which comprises a main body and a secondary battery, wherein the secondary battery is a plurality of and is arranged in the main body.

The utility model has the advantages as follows: the application of the insulating part can fix the fusing part, so that the shock resistance of the fusing part is improved, and the risk of fracture of the fusing part in the normal working process of the secondary battery is reduced. In addition, the insulating part covers the fusing part, so that the fusing part can be ensured to be in a relatively sealed environment; when the fusing part is fused, the insulating part can prevent other substances from entering the fusing area and prevent the electrode lead from being conducted again. When the fusing part is fused, the insulating part can also fix the residual part of the fusing part; when the secondary battery vibrates, the insulating member can prevent the melted electrode leads from being overlapped again, thereby improving the safety performance of the secondary battery.

Drawings

FIG. 1 is a schematic view of a vehicle.

Fig. 2 is a schematic view of a battery module.

Fig. 3 is a schematic view of a secondary battery.

Fig. 4 is a schematic view of a packaging bag for a secondary battery before molding.

Fig. 5 is a sectional view of a packaging film of a packaging bag for a secondary battery.

Fig. 6 is a cross-sectional view taken along line a-a of fig. 3.

Fig. 7 is a cross-sectional view taken along line B-B of fig. 3.

Fig. 8 is a cross-sectional view taken along line C-C of fig. 3.

Fig. 9 is an assembly view of the electrode lead and the insulator.

Fig. 10 is a schematic view of an electrode lead.

Wherein the reference numerals are as follows:

1 electrode Assembly

2 packaging bag

21 packaging film

22 sealing part

23 protective layer

24 metal layer

25 connecting layer

3 electrode lead

31 fusing part

311 sub-fusing part

32 fuse hole

33 inner extension

34 outer extension part

4 insulating part

41 first insulating part

42 second insulating part

43 cylindrical part

44 connecting part

5 Secondary Battery

In the X longitudinal direction

Y width direction

In the Z thickness direction

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

In the description of the present application, unless explicitly stated or limited otherwise, the terms "first", "second", and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance; the term "plurality" means more than two (including two); the term "coupled", unless otherwise specified or indicated, is to be construed broadly, e.g., "coupled" may be a fixed or removable connection or a connection that is either integral or electrical or signal; "connected" may be directly connected or indirectly connected through an intermediate. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

In the description of the present application, it should be understood that the terms "upper" and "lower" used in the description of the embodiments of the present application are used in a descriptive sense only and not for purposes of limitation. The present application is described in further detail below with reference to specific embodiments and with reference to the attached drawings.

The present application provides a device using a secondary battery as a power source, which includes a main body and a secondary battery 5, the secondary battery 5 being plural and provided in the main body. Referring to fig. 1, the device may be a ship, a vehicle, or the like. The vehicle is a new energy automobile, which can be a pure electric automobile, a hybrid electric automobile or a range-extended automobile. The main body of the vehicle is provided with a driving motor, the driving motor is electrically connected with the secondary battery 5, the secondary battery 5 provides electric energy, and the driving motor is connected with wheels on the main body of the vehicle through a transmission mechanism so as to drive the vehicle to move. The secondary battery 5 is a lithium ion battery.

The present application also provides a battery module, and referring to fig. 2, the battery module includes a plurality of secondary batteries 5, the plurality of secondary batteries 5 being arranged in sequence. The battery module may further include a support frame that receives and fixes the plurality of secondary batteries 5.

Referring to fig. 3 to 7, the secondary battery of the present application includes an electrode assembly 1, a packaging bag 2, an electrode lead 3, and an insulator 4.

The electrode assembly 1 is a core member of the secondary battery that realizes the charge and discharge functions. 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. The positive pole piece comprises a positive current collector and a positive active substance layer coated on the surface of the positive current collector, the positive current collector can be an aluminum foil, and the positive active substance layer comprises a ternary material, lithium manganate or lithium iron phosphate. The negative pole piece comprises a negative current collector and a negative active substance layer coated on the surface of the negative current collector, the negative current collector can be a copper foil, and the negative active substance layer comprises graphite or silicon.

The electrode assembly 1 may be of a wound structure. Specifically, the positive electrode plate and the negative electrode plate are both one, and the positive electrode plate and the negative electrode plate are in a belt-shaped structure. The positive electrode sheet, separator and negative electrode sheet were sequentially laminated and wound two or more turns to form an electrode assembly 1. The electrode assembly 1 may be flat.

Alternatively, the electrode assembly 1 may also be of a laminated structure. Specifically, the positive electrode plate is provided in plurality, the negative electrode plate is provided in plurality, the positive electrode plates and the negative electrode plates are alternately stacked in the thickness direction Z, and the positive electrode plates and the negative electrode plates are separated by the diaphragm.

The packaging bag 2 includes two layers of packaging films 21, and the two layers of packaging films 21 are arranged up and down in the thickness direction Z of the secondary battery. Referring to fig. 4, at least one of the packaging films 21 is punched to form a cavity, and the electrode assembly 1 is located between the two packaging films 21 and is accommodated in the cavity.

The two layers of packaging films 21 may be integrally or separately provided. For example, the two-layer packaging film 21 may be formed by bending a single packaging film (e.g., an aluminum plastic film, a steel plastic film, etc.). Specifically, referring to fig. 4, two cavities may be formed in the sheet of packaging film by punching, and then the sheet of packaging film is bent into two layers, i.e., two layers of packaging film 21 of the present application are formed.

Referring to fig. 5, each of the packaging films 21 includes a protective layer 23, a metal layer 24, and a connection layer 25, and the protective layer 23 and the connection layer 25 are respectively disposed on both sides of the metal layer 24. Specifically, the protective layer 23 may be fixed to the surface of the metal layer 24, which is remote from the electrode assembly 1, by an adhesive, and the connection layer 25 may be fixed to the surface of the metal layer 24, which is close to the electrode assembly 1, by an adhesive.

The material of the protection layer 23 may be nylon or polyethylene terephthalate, the material of the metal layer 24 may be aluminum foil or steel foil, and the material of the connection layer 25 may be polypropylene.

The two layers of packaging film 21 are joined at the edges and form a seal 22. Specifically, the connecting layers 25 of the two packaging films 21 are directly or indirectly joined together by heat pressing, thereby forming the sealed packaging bag 2. During the heat pressing, the connecting layer 25 is melted and compressed, and therefore, after the heat press molding, the thickness of the sealing portion 22 is smaller than the sum of the thicknesses of the two packaging films 21 before the heat pressing. The sealing portion 22 seals a space in which the electrode assembly 1 is housed, and prevents leakage of the electrolyte.

Referring to fig. 3 and 7, the electrode lead 3 is connected to the electrode assembly 1, passes through the sealing part 22, and extends to the outside of the pouch 2. Specifically, the number of the electrode leads 3 may be two, one electrode lead 3 is connected to the positive current collector of the positive electrode plate, and the other electrode lead 3 is connected to the negative current collector of the negative electrode plate. The two electrode leads 3 connect the electrode assembly 1 with other members outside the package bag 2, thereby achieving charge and discharge of the electrode assembly 1. The material of the electrode lead 3 may be aluminum, nickel or copper-plated nickel. In some embodiments, two electrode leads 3 extend from the same side of the package 2. In some alternative embodiments, two electrode leads 3 may also be extended from opposite sides of the package 2, respectively.

The electrode lead 3 passes through between the two packaging films 21. Since the connection layer 25 is thin, the electrode lead 3 is easily brought into contact with the metal layer 24, causing a safety risk. Therefore, the secondary battery of the present application is preferably provided with the insulator 4.

The insulating member 4 may be two. The two insulators 4 respectively separate the two electrode leads 3 from the sealing part 22. Each of the insulators 4 surrounds the outside of a corresponding one of the electrode leads 3 and is connected to the sealing portion 22. A portion of the insulator 4 is sandwiched between the two packaging films 21, thereby separating the electrode lead 3 from the packaging bag 2, reducing the risk of the electrode lead 3 coming into contact with the metal layer 24. The material of the insulating member 4 may be polypropylene.

Since a part of the insulating member 4 is sandwiched between the two packaging films 21, the connecting layer 25 of the two packaging films 21 is welded to the insulating member 4 at the time of hot pressing.

When the secondary battery is short-circuited, a great current is generated, the heat generated by the battery is rapidly increased, and the thermal runaway inside the battery is easily caused, so that the safety accidents such as combustion, even explosion and the like of the battery occur. In order to improve the safety performance of the secondary battery, the electrode lead 3 of the present application is provided with the fusing part 31.

When the secondary battery appears the short circuit, will produce heavy current, heavy current can produce high temperature when flowing through fusing portion 31, and high temperature can be with fusing portion 31 fusing to in time cut off circuit avoids the inside thermal runaway of battery.

In the present application, the insulating member 4 covers and is connected to the fusing part 31. The strength of the fusing part 31 is low, and there is a risk that the fusing part 31 is broken when the secondary battery vibrates. And insulating part 4 of this application can fix fusing portion 31, and then improves fusing portion 31's shock resistance, reduces fusing portion 31 fracture's when secondary battery normal operating risk. In addition, the insulating member 4 covers the fusing part 31, so that the fusing part 31 can be ensured to be in a relatively sealed environment; when the fusing part 31 is fused, the insulating member 4 prevents other substances from entering the fusing region and prevents the electrode leads 3 from being conducted again.

In addition, when the fusing part 31 is fused, the insulating member 4 may fix a remaining portion of the fusing part 31; when the secondary battery vibrates, the insulating member 4 can prevent the melted electrode lead 3 from being overlapped again, thereby improving the safety of the secondary battery.

Referring to fig. 8 to 10, the electrode lead 3 further includes an inner extension 33 and an outer extension 34, and the fusing part 31 is connected between the inner extension 33 and the outer extension 34. An end of the inner extension 33 away from the fusing part 31 is located inside the packing bag 2, and an end of the outer extension 34 away from the fusing part 31 is located outside the packing bag 2. The inner extension 33 is connected to the electrode assembly 1, and the outer extension 34 may be used to electrically connect with other members outside the pouch 2.

The electrode lead 3 is provided with a fusing hole 32. By providing the fusing hole 32, the sectional area of a partial region of the electrode lead 3 can be reduced, thereby forming the fusing part 31 having a safety protection function. The fusing hole 32 is arranged side by side with the fusing part 31 in the width direction of the electrode lead 3, and the size of the fusing part 31 is smaller than that of the other portion of the electrode lead 3.

The fusing part 31 includes a plurality of sub fusing parts 311, and the fusing hole 32 is disposed between adjacent sub fusing parts 311. The plurality of sub fusing parts 311 are connected between the inner extending part 33 and the outer extending part 34.

The insulating member 4 has a cylindrical portion 43 extending into the fuse hole 32. The cylindrical portion 43 is located between the inner extension 33 and the outer extension 34. After the fusing part 31 is fused, the cylindrical part 43 can block the inner extending part 33 and the outer extending part 34, so that the inner extending part 33 and the outer extending part 34 are prevented from being close to each other and overlapped, the risk of circuit reconduction is reduced, and the safety performance is improved.

The fusing hole 32 is provided in plurality, the column portion 43 is provided in plurality, and each fusing hole 32 is provided corresponding to each column portion 43.

The insulating member 4 further has a first insulating portion 41 and a second insulating portion 42, the first insulating portion 41 and the second insulating portion 42 being located on both sides of the electrode lead 3 in the thickness direction Z and covering the fusing portion 31, respectively. The cylindrical portion 43 connects the first insulating portion 41 and the second insulating portion 42 to improve the connection strength between the first insulating portion 41 and the second insulating portion 42, reducing the risk of the insulating member 4 being separated from the electrode lead 3.

The insulating member 4 further has two connecting portions 44, the two connecting portions 44 being located at both sides of the electrode lead 3 in the width direction Y thereof, respectively, each connecting portion 44 connecting the first insulating portion 41 and the second insulating portion 42.

The insulator 4 may be formed on the electrode lead 3 by injection molding. By providing the columnar portion 43, the connection area of the insulator 4 and the electrode lead 3 can be increased, and the connection strength of the insulator 4 and the electrode lead 3 can be improved.

The first and second insulating

portions

41 and 42 cover a part of the inner extending portion 33, and the first and second insulating

portions

41 and 42 cover a part of the outer extending portion 34. The first insulating portion 41 and the second insulating portion 42 are connected to a portion of the inner extension portion 33 adjacent to the fusing portion 31, so that when the fusing portion 31 is fused, the first insulating portion 41 and the second insulating portion 42 can fix the inner extension portion 33, prevent the inner extension portion 33 from shaking in the packing bag 2, and prevent the packing bag 2 from being punctured by the inner extension portion 33. The first insulating portion 41 and the second insulating portion 42 are connected to a portion of the externally extending portion 34 adjacent to the fusing portion 31, and therefore, when the fusing portion 31 is fused, the first insulating portion 41 and the second insulating portion 42 can fix the externally extending portion 34, thereby preventing the externally extending portion 34 from falling off the secondary battery and reducing safety risk.

The sealing portion 22 is welded to at least a portion of the first insulating portion 41 covering the fusing portion 31 and a portion of the second insulating portion 42 covering the fusing portion 31. At this time, the sealing portion 22 surrounding the fusing portion 31 may further fix the fusing portion 31. Meanwhile, the fusing part 31 can be prevented from occupying the inner space of the packaging bag 2, and the energy density of the secondary battery can be improved.

The ratio of the area of the cross section of the fusing part 31 to the area of the cross section of the other part of the electrode lead 3 is 0.3-0.8. Wherein the cross section is a cross section perpendicular to the length direction X of the electrode lead 3. If the ratio is too small, the temperature of the fusing part 31 is too high when the secondary battery normally works, which affects the working performance of the secondary battery; in an extreme case, the fusing part 31 may be fused even when the secondary battery is normally operated. If the ratio is too large, the fusing part 31 cannot be fused in time when the secondary battery is short-circuited, and thus the safety protection function cannot be performed.

Claims

1. A secondary battery, characterized by comprising an electrode assembly (1), a packaging bag (2), an electrode lead (3), and an insulator (4);

the electrode assembly (1) is accommodated in the packaging bag (2), the edge of the packaging bag (2) is provided with a sealing part (22), and the electrode lead (3) is connected to the electrode assembly (1) and penetrates through the sealing part (22);

the insulator (4) surrounds the outside of the electrode lead (3) and is connected to the sealing part (22), and the insulator (4) separates the sealing part (22) from the electrode lead (3);

the electrode lead (3) has a fusing part (31), and the insulating member (4) covers and is connected to the fusing part (31).

2. The secondary battery according to claim 1,

the electrode lead (3) is provided with a fusing hole (32), the fusing hole (32) and the fusing part (31) are arranged side by side along the width direction of the electrode lead (3), and the size of the fusing part (31) is smaller than that of other parts of the electrode lead (3);

the insulating member (4) has a cylindrical portion (43) extending into the fuse hole (32).

3. The secondary battery according to claim 2, wherein the fusing hole (32) is plural, the cylindrical portion (43) is plural, and each fusing hole (32) is provided corresponding to each cylindrical portion (43).

4. The secondary battery according to claim 2,

the insulating member (4) further has a first insulating portion (41) and a second insulating portion (42), the first insulating portion (41) and the second insulating portion (42) are respectively located on both sides of the electrode lead (3) in the thickness direction (Z) and cover the fusing portion (31), and the column portion (43) connects the first insulating portion (41) and the second insulating portion (42).

5. The secondary battery according to claim 4,

the electrode lead (3) further comprising an inner extension (33) and an outer extension (34), the fusing part (31) being connected between the inner extension (33) and the outer extension (34);

one end of the inner extension part (33) far away from the fusing part (31) is positioned inside the packaging bag (2), and one end of the outer extension part (34) far away from the fusing part (31) is positioned outside the packaging bag (2);

the first insulating portion (41) and the second insulating portion (42) cover a part of the inner extension portion (33), and the first insulating portion (41) and the second insulating portion (42) cover a part of the outer extension portion (34).

6. The secondary battery according to claim 4, wherein the sealing portion (22) is welded to at least a portion of the first insulating portion (41) that covers the fusing portion (31) and a portion of the second insulating portion (42) that covers the fusing portion (31).

7. The secondary battery according to claim 1,

the ratio of the area of the cross section of the fusing part (31) to the area of the cross section of the other part of the electrode lead (3) is 0.3-0.8;

the cross section is a cross section perpendicular to the length direction (X) of the electrode lead (3).

8. The secondary battery according to any one of claims 1 to 7,

the packaging bag (2) comprises two packaging films (21), the electrode assembly (1) is positioned between the two packaging films (21), and the two packaging films (21) are connected at the edges and form the sealing part (22);

each packaging film (21) comprises a protective layer (23), a metal layer (24) and a connecting layer (25), wherein the connecting layer (25) is arranged on the surface of the metal layer (24) facing the electrode assembly (1), and the protective layer (23) is arranged on the surface of the metal layer (24) far away from the electrode assembly (1);

the electrode lead (3) penetrates through the two layers of packaging films (21).

9. A battery module characterized by comprising the secondary battery according to any one of claims 1 to 8, the secondary battery being a plurality of secondary batteries.

10. A device comprising a main body and the secondary battery according to any one of claims 1 to 8, wherein the secondary battery is plural and provided to the main body.