CN210403894U

CN210403894U - Secondary battery

Info

Publication number: CN210403894U
Application number: CN201921493113.4U
Authority: CN
Inventors: 陈元宝; 李全坤; 王鹏
Original assignee: Contemporary Amperex Technology Co Ltd
Current assignee: Contemporary Amperex Technology Co Ltd
Priority date: 2019-09-09
Filing date: 2019-09-09
Publication date: 2020-04-24
Anticipated expiration: 2029-09-09

Abstract

The utility model provides a secondary battery, it includes electrode subassembly, casing, top cap subassembly and switching component. The electrode assembly is housed in the case. The top cover assembly includes a top cover plate having a terminal hole and an electrode terminal disposed on the top cover plate and covering the terminal hole. The adaptor member includes a main body part disposed at a side of the top cap plate adjacent to the electrode assembly and connected to the electrode assembly, and a protrusion part connected to the main body part and extending toward the electrode terminal. The protrusion has a top wall and a side wall at least partially disposed within the terminal aperture, the side wall and the top wall configured as a cavity, and the side wall coupled between the top wall and the body portion. The top wall includes a connection region fixed to the electrode terminal and a fuse region connected between the side wall and the connection region.

Description

Secondary battery

Technical Field

The utility model relates to a battery field especially relates to a secondary battery.

Background

A secondary battery generally includes an electrode assembly, a case housing the electrode assembly, and a cap assembly fixed to the case, and a cap plate of the cap assembly seals the case. The top cover assembly further comprises an electrode terminal protruding from the top cover plate for electrical connection with an external device. In order to be electrically connected with the electrode assembly, a portion of the electrode terminal generally extends into the interior of the case, causing the electrode terminal to occupy the internal space of the secondary battery, affecting the energy density of the secondary battery.

SUMMERY OF THE UTILITY MODEL

In view of the problems in the background art, an object of the present invention is to provide a secondary battery capable of improving energy density and reducing safety risk.

In order to accomplish the above object, the present invention provides a secondary battery including an electrode assembly, a case, a cap assembly, and an adapting member. The electrode assembly is housed in the case. The top cover assembly includes a top cover plate having a terminal hole and an electrode terminal disposed on the top cover plate and covering the terminal hole. The adaptor member includes a main body part disposed at a side of the top cap plate adjacent to the electrode assembly and connected to the electrode assembly, and a protrusion part connected to the main body part and extending toward the electrode terminal. The protrusion has a top wall and a side wall at least partially disposed within the terminal aperture, the side wall and the top wall configured as a cavity, and the side wall coupled between the top wall and the body portion. The top wall includes a connection region fixed to the electrode terminal and a fuse region connected between the side wall and the connection region.

In some embodiments, the top wall has a recess, the recess being located on one side of the fuse region.

In some embodiments, the recess is located on a side of the fuse region proximate the cavity, and the recess is recessed relative to a surface of the top wall proximate the cavity.

In some embodiments, the top wall has a through-hole, and the through-hole is located between the connection region and the side wall.

In some embodiments, the through hole is plural, the fuse region is plural, and the plural through holes and the plural fuse regions are surrounded on the outer side of the connection region and alternately arranged in the circumferential direction of the connection region.

The secondary battery further includes an insulating member including a first portion and a second portion. The first portion is received in the cavity and secured to the protrusion, and the second portion extends from a surface of the first portion adjacent the top wall and is inserted into the through hole.

The first portion covers a surface of the top wall adjacent the cavity.

The top wall further includes a transition region surrounding an outer side of the fuse region and connecting the side wall and the fuse region.

The transition area is circular ring shape, and the width of transition area is greater than 0.5 mm.

The connection region is welded to the electrode terminal and forms a welding region, and a distance between the welding region and the fusing region is greater than 0.5 mm.

The utility model has the advantages as follows: by disposing the electrode terminal to the outside of the cap plate, the internal space of the secondary battery occupied by the electrode terminal can be reduced, and the energy density can be improved. The present application can conveniently connect the adaptor member and the electrode terminal by providing the adaptor member with a protrusion that can be inserted into the terminal hole. When the secondary battery is short-circuited due to an unexpected condition, the current of the switching member is rapidly increased, and the fusing area generates high temperature and fuses under the action of the current, so that the circuit is cut off in time, and the safety risk is reduced. And this application sets up the fusing area to the roof on, can reduce the pulling force that the fusing area received in stamping process to reduce the cracked risk of fusing area, guarantee switching component's the ability of overflowing, improve the security performance.

Drawings

Fig. 1 is a schematic view of a secondary battery according to the present invention.

Fig. 2 is a sectional view of a secondary battery according to the present invention.

Fig. 3 is an enlarged view of the secondary battery of fig. 2 at block a.

Fig. 4 is a schematic view of an electrode assembly of a secondary battery according to the present invention.

Fig. 5 is a schematic diagram of the first pole piece in an expanded state according to an embodiment of the present invention.

Fig. 6 is a cross-sectional view of the first pole piece of fig. 5 taken along line B-B.

Fig. 7 is a schematic view of an embodiment of an adapter member according to the present invention.

Fig. 8 is a bottom view of the adapter member of fig. 7.

Fig. 9 is a cross-sectional view of the electrode member of fig. 8 taken along line C-C.

Fig. 10 is an enlarged view of the electrode member of fig. 9 at circle D.

Fig. 11 is a schematic view of the interposer fabric of fig. 7 prior to stamping.

Fig. 12 is a schematic view of another embodiment of an adapter member according to the present invention.

Fig. 13 is an enlarged view of the adapter member of fig. 12 at circle E.

Fig. 14 is a bottom view of the adapter member of fig. 12.

Fig. 15 is a schematic view of an adapter member and insulator according to the present invention.

Fig. 16 is a cross-sectional view taken along line F-F of fig. 15.

Wherein the reference numerals are as follows:

1 electrode Assembly

11 first tab

12 second ear

13 first pole piece

131 first current collector

132 first active material layer

14 second pole piece

15 diaphragm

2 casing

3 Top cover assembly

31 ceiling board

311 terminal hole

32 electrode terminal

4 switching component

41 body part

42 projection

421 top wall

4211 linking region

4212 fusing region

4213 transition zone

4214 groove

4215 through hole

422 side wall

43 concave cavity

5 insulating part

51 first part

52 second part

W weld zone

In the X longitudinal direction

Y width direction

Direction of Z height

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.

Referring to fig. 1 to 3, the secondary battery of the present application includes an electrode assembly 1, a case 2, a cap assembly 3, and an adapting member 4.

The electrode assembly 1 is a core member of the secondary battery that realizes the charge and discharge functions. Referring to fig. 4, the electrode assembly 1 includes a first pole piece 13, a second pole piece 14, and a separator 15, the separator 15 being disposed between the first pole piece 13 and the second pole piece 14. The first pole piece 13, the separator 15, and the second pole piece 14 are sequentially laminated and spirally wound to form the electrode assembly 1. The electrode assembly 1 is flat.

Referring to fig. 5 and 6, the first electrode sheet 13 includes a first current collector 131 and a first active material layer 132 coated on a surface of the first current collector 131. The first electrode sheet 13 may be a positive electrode sheet, the first current collector 131 is an aluminum foil, and the first active material layer 132 includes a ternary material, lithium manganate or lithium iron phosphate. The active material (e.g., ternary material, lithium manganate, lithium iron phosphate), the binder, the conductive agent, and the solvent may be prepared into a slurry, and then the slurry is coated on both surfaces of the first current collector 131, and the first active material layer 132 is formed after the slurry is cured.

The first current collector 131 is coated with the first active material layer 132 only in a partial area. Referring to fig. 6, the first active material layer 132 and the area of the first current collector 131 coated with the first active material layer 132 form a first coated area of the first pole piece 13, and the area of the first current collector 131 not coated with the first active material layer 132 form a first blank area of the first pole piece 13.

The first blank regions may be a plurality of and arranged at intervals, and the plurality of first blank regions are laminated together when the electrode assembly 1 is wound.

The second pole piece 14 includes a second current collector and a second active material layer coated on the surface of the second current collector, the second active material layer and the area of the second current collector coated with the second active material layer form a second coating area of the second pole piece 14, and the area of the second current collector not coated with the second active material layer form a second blank area of the second pole piece 14. The second blank regions may be a plurality of and arranged at intervals, and the plurality of second blank regions are laminated together when the electrode assembly 1 is wound. The structure of the second electrode sheet 14 is similar to that of the first electrode sheet 13, except that the second current collector is made of copper foil, and the second active material layer includes graphite or silicon.

The diaphragm 15 can be a Polyethylene (PE) film, a polypropylene (PP) film or a PP \ PE \ PP three-layer composite film.

After the electrode assembly 1 is wound, a plurality of first blank regions of the first pole piece 13 are laminated together and serve as the first tab 11 of the electrode assembly 1, and a plurality of second blank regions of the second pole piece 14 are laminated together and serve as the second tab 12 of the electrode assembly 1.

The winding axis of the electrode assembly 1 is parallel to the height direction Z, and the first and

second tabs

11 and 12 are disposed at the upper end of the electrode assembly 1 in the height direction Z.

Referring to fig. 1 and 2, the case 2 may have a hexahedral shape or other shapes. The case 2 forms a receiving chamber therein to receive the electrode assembly 1 and the electrolyte. The case 2 is formed with an opening at one end, and the electrode assembly 1 may be placed into the receiving cavity of the case 2 through the opening. The housing 2 may be made of a material that is a conductive metal, and in some embodiments, the housing 2 is made of aluminum or an aluminum alloy.

The top lid assembly 3 includes a top lid plate 31 and an electrode terminal 32, and the electrode terminal 32 is provided to the top lid plate 31. The size of the top cover plate 31 is adapted to the size of the opening of the housing 2. The top cap plate 31 may be connected to the case 2 by welding or the like and covers the opening of the case 2, thereby sealing the electrode assembly 1 within the case 2. The ceiling plate 31 may be made of a metal material such as aluminum, aluminum alloy, or the like. The two electrode terminals 32 are electrically connected to the first tab 11 and the second tab 12, respectively.

The top lid plate 31 has a through terminal hole 311. Correspondingly, the terminal holes 311 are provided in two. One electrode terminal 32 is disposed on the side of the top cap plate 31 remote from the electrode assembly 1 and covers one terminal hole 311, and the other electrode terminal 32 is disposed on the side of the top cap plate 31 remote from the electrode assembly 1 and covers the other terminal hole 311. The electrode terminal 32 may be completely located outside the terminal hole 311, may be partially accommodated in the terminal hole 311, or may be completely accommodated in the terminal hole 311.

In the present application, by disposing the electrode terminal 32 to the outside of the cap plate 32, the occupation of the electrode terminal 32 in the internal space of the secondary battery can be reduced, and the energy density can be improved. Meanwhile, the sealing ring between the electrode terminal 32 and the cap plate 31 may also be provided to the outside of the cap plate 32 without occupying the inner space of the secondary battery.

The electrode terminals 32 may be electrically connected to the electrode assembly 1 through the relay member 4. The adapting member 4 may be two, one adapting member 4 connecting one electrode terminal 32 and the first tab 11, and the other adapting member 4 connecting the other electrode terminal 32 and the second tab 12.

Referring to fig. 7 to 10, the transit member 4 includes a body portion 41 and a protrusion 42, the body portion 41 being disposed on a side of the top cap plate 31 adjacent to the electrode assembly 1 and connected to the electrode assembly 1, and the protrusion 42 being connected to the body portion 41 and extending toward the electrode terminal 32. The first tab 11 or the second tab 12 is fixed to the body portion 41 of the adapting member 4 by ultrasonic welding.

The main body 41 has a substantially flat plate shape, and the projection 42 projects from the main body 41 in a direction toward the electrode terminal 32. The protrusion 42 has a top wall 421 and a side wall 422, the side wall 422 being at least partially disposed within the terminal hole 311. The side wall 422 and the top wall 421 configure the cavity 43, and the opening of the cavity 43 faces the electrode assembly 1. The side wall 422 is connected between the top wall 421 and the main body portion 41. The side wall 422 is a hollow cylinder and surrounds the outside of the top wall 421, and in some embodiments, the side wall 422 is a hollow cylinder. The top wall 421 is substantially flat.

The top wall 421 includes a connection region 4211 and a fuse region 4212, the connection region 4211 is fixed to the electrode terminal 32, and the fuse region 4212 is connected between the side wall 422 and the connection region 4211. The fusing region 4212 is weaker than the connection region 4211, and has a smaller flow area than the connection region 4211 and the side wall 422.

In the present invention, the protrusion 42 capable of being inserted into the terminal hole 311 is provided on the adapter member 4, so that the adapter member 4 and the electrode terminal 32 can be easily connected. When the secondary battery is short-circuited due to an unexpected condition, the current of the adapting member 4 is rapidly increased, and the fusing region 4212 generates high temperature and fuses under the action of the current, so that the circuit is cut off in time, and the safety risk is reduced.

The projections 42 and the cavities 43 may be formed by stamping. Referring to fig. 11, initially, the relay member 4 is a flat plate-shaped metal sheet, and then a groove 4214 or a through hole 4215 described later is provided in the metal sheet to form a fuse region 4212, and finally a protrusion 42 is formed in the metal sheet by pressing. During stamping, the side walls 422 are formed by stretching the sheet metal. The fuse region 4212 is weak, and if the fuse region 4212 is located on the side wall 422, the fuse region 4212 is easily cracked during punching, which affects the overcurrent capacity and the fuse current of the fuse region 4212. In severe cases, the fuse region 4212 may even risk being pulled apart, resulting in failure of the transition member 4.

And this application sets up fusing area 4212 to on the roof 421, can reduce the pulling force that fusing area 4212 received in stamping process to reduce fusing area 4212 cracked risk, guarantee switching component 4's overcurrent ability, improve the security performance.

In addition, since the first tab 11 or the second tab 12 is welded to the body portion 41, there is a difference in height between the tab and the connection region 4211, and there is no risk that the tab overlaps the connection region 4211.

Referring to fig. 10, the top wall 421 further includes a transition region 4213, and the transition region 4213 surrounds the outside of the fusing region 4212 and connects the side wall 422 and the fusing region 4212. By providing the transition zone 4213, the distance between the weld zone 4212 and the side wall 422 can be increased, the force applied to the weld zone 4212 during the stamping process can be reduced, and the risk of fracture of the weld zone 4212 can be reduced.

Transition zone 4213 is circular ring shaped, and the width of transition zone 4213 is greater than 0.5 mm. If the width of transition zone 4213 is too small, the cushioning effect of transition zone 4213 is not significant.

The connection region 4211 is welded to the electrode terminal 32 and forms a welding region W. For example, the connection region 4211 may be fixed to the electrode terminal 32 by laser welding. A large amount of heat is generated during the welding, and if the distance between the welding region W and the fusing region 4212 is too small, the amount of heat transferred to the fusing region 4212 is large, which easily causes the risk of fusing the fusing region 4212. Therefore, it is preferable that the interval between the welding region W and the fusing region 4212 is greater than 0.5 mm.

In some embodiments, referring to fig. 9 and 10, the top wall 421 has a groove 4214, and the groove 4214 is located at one side of the fuse region 4212. The groove 4214 may be located at an upper or lower side of the fusing region 4212 in the height direction Z. The groove 4214 can reduce the flow area of the fusing region 4212, thereby realizing the fusing protection function of the fusing region 4212. The groove 4214 is annular and surrounds the outside of the connection region 4211. The cross-section of the groove 4214 may be trapezoidal, triangular or rectangular.

In the punching process, a punch punches a metal sheet from one side; the elongation of the surface of the metal sheet facing away from the punch is greater than the elongation of the surface of the metal sheet facing the punch. That is, if the groove 4214 is opened on the surface of the metal sheet away from the punch, the force received by the metal sheet at the groove 4214 is large; if the surface of the sheet metal close to the punch is provided with a groove 4214, the sheet metal is subjected to a smaller force at the groove 4214. Therefore, in some embodiments of the present application, when the adapting member 4 is stamped and formed, the groove 4214 is located on a side of the fusing region 4212 adjacent to the cavity 43, and the groove 4214 is recessed relative to a surface of the top wall 421 adjacent to the cavity 43.

In some embodiments, referring to fig. 12-14, the top wall 421 has a through hole 4215, and the through hole 4215 is located between the connection region 4211 and the sidewall 422. By providing the through hole 4215 between the connection region 4211 and the sidewall 422, the sectional area of the fusing region 4212 between the connection region 4211 and the sidewall 422 may be reduced, thereby implementing a fusing protection function of the fusing region 4212.

The through hole 4215 is plural, the fusing region 4212 is plural, and the plural through holes 4215 and the plural fusing regions 4212 are surrounded on the outer side of the connection region 4211 and are alternately arranged in the circumferential direction of the connection region 4211. The plurality of fuse regions 4212 may improve the structural strength of the top wall 421.

The flow areas of the at least two fuse regions 4212 are different. The fusing regions 4212 can be sequentially fused according to a set sequence by different overcurrent areas, so that fusing efficiency is improved.

The transition region 4213 surrounds the outside of the plurality of fuse regions 4212 and connects the plurality of fuse regions 4212 together.

In some embodiments, referring to fig. 15 and 16, the secondary battery further includes an insulating member 5, and the insulating member 5 includes a first portion 51 and a second portion 52. The first portion 51 is received in the cavity 43 and fixed to the protrusion 42, and the second portion 52 extends from a surface of the first portion 51 adjacent to the top wall 421 and is inserted into the through hole 4215.

When the fuse region 4212 fuses, the circuit is cut. However, when the secondary battery vibrates, the side wall 422 and the transition region 4213 may come into contact with the connection region 4211, causing the circuit to be turned back on, causing a safety risk. While the second portion 52 inserted into the through hole 4215 may separate the transition zone 4213 from the connection zone 4211, reducing the risk of circuit re-conduction.

The first portion 51 is adhered to the inner surface of the top wall 421 and covers the surface of the top wall 421 adjacent to the cavity 43. When the welding of the relay member 4 and the electrode terminal 32 is completed, metal impurities remain on the surface of the welding area W, and the metal impurities may cause a risk of short-circuiting when falling into the electrode assembly 1. And the first portion 51 may fix the metal impurities between the top wall 421 and the first portion 51, thereby reducing the risk of the metal impurities falling into the electrode assembly 1.

Claims

1. A secondary battery characterized by comprising an electrode assembly (1), a case (2), a cap assembly (3), and an adapter member (4);

the electrode assembly (1) is accommodated in the shell (2);

the top cover assembly (3) comprises a top cover plate (31) and an electrode terminal (32), wherein the top cover plate (31) is provided with a terminal hole (311), and the electrode terminal (32) is arranged on the top cover plate (31) and covers the terminal hole (311);

the adapter member (4) comprises a main body part (41) and a protrusion part (42), wherein the main body part (41) is arranged on one side of the top cover plate (31) close to the electrode assembly (1) and connected to the electrode assembly (1), and the protrusion part (42) is connected to the main body part (41) and extends towards the electrode terminal (32);

the protrusion (42) is provided with a top wall (421) and a side wall (422), the side wall (422) is at least partially arranged in the terminal hole (311), the side wall (422) and the top wall (421) are constructed into a cavity (43), and the side wall (422) is connected between the top wall (421) and the main body part (41);

the top wall (421) includes a connection region (4211) and a fuse region (4212), the connection region (4211) is fixed to the electrode terminal (32), and the fuse region (4212) is connected between the side wall (422) and the connection region (4211).

2. The secondary battery according to claim 1, wherein the top wall (421) has a groove (4214), and the groove (4214) is located at one side of the fusing region (4212).

3. The secondary battery according to claim 2,

the groove (4214) is positioned on one side of the fusing region (4212) close to the cavity (43), and the groove (4214) is recessed relative to the surface of the top wall (421) close to the cavity (43).

4. The secondary battery according to claim 1, wherein the top wall (421) has a through hole (4215), and the through hole (4215) is located between the connection region (4211) and the side wall (422).

5. The secondary battery according to claim 4, wherein the through hole (4215) is plural, the fusing region (4212) is plural, and the plural through holes (4215) and the plural fusing regions (4212) are surrounded outside the connection region (4211) and are alternately arranged in a circumferential direction of the connection region (4211).

6. The secondary battery according to claim 5,

the secondary battery further includes an insulating member (5), the insulating member (5) including a first portion (51) and a second portion (52);

the first portion (51) is accommodated in the cavity (43) and fixed to the protrusion (42), and the second portion (52) extends from the surface of the first portion (51) close to the top wall (421) and is inserted into the through hole (4215).

7. The secondary battery according to claim 6, wherein the first portion (51) covers a surface of the top wall (421) near the cavity (43).

8. The secondary battery according to any one of claims 1 to 7, wherein the top wall (421) further comprises a transition region (4213), the transition region (4213) surrounding an outside of the fusing region (4212) and connecting the side wall (422) and the fusing region (4212).

9. The secondary battery according to claim 8, wherein the transition region (4213) is annular, and the width of the transition region (4213) is greater than 0.5 mm.

10. The secondary battery according to claim 1, wherein the connection region (4211) is welded to the electrode terminal (32) and forms a welding region (W), and the welding region (W) is spaced apart from the fusing region (4212) by more than 0.5 mm.