CN210136949U

CN210136949U - Secondary battery

Info

Publication number: CN210136949U
Application number: CN201921428578.1U
Authority: CN
Inventors: 柴志生; 迟庆魁; 王升威; 肖海河
Original assignee: Contemporary Amperex Technology Co Ltd
Current assignee: Contemporary Amperex Technology Co Ltd
Priority date: 2019-08-29
Filing date: 2019-08-29
Publication date: 2020-03-10
Anticipated expiration: 2029-08-29

Abstract

The utility model provides a secondary battery, it includes electrode subassembly, casing, top cap subassembly and current collection component. The electrode assembly is accommodated in the case and includes a main body portion and a first tab extending from one end of the main body portion in a length direction. The top cap assembly includes a top cap plate connected to the case and a first electrode terminal. The current collecting member connects the first electrode terminal and the first tab. The current collecting member includes a substrate disposed at one side of the body portion in the length direction and perpendicular to the length direction, and a support plate. The base plate comprises a first part and a second part, and the second part is connected to one end, far away from the top cover plate, of the first part in the height direction. In the width direction, the edge of the second portion is recessed inward relative to the edge of the first portion and forms a notch. The support plate extends from an edge of the second portion near the notch and is folded back to a side of the second portion away from the main body portion. The first tab is connected to the support plate, and a portion of the first tab is located in the notch.

Description

Secondary battery

Technical Field

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

Background

The secondary battery generally includes an electrode assembly, a case, electrode terminals, and a current collecting member for electrically connecting the electrode assembly and the electrode terminals. In the secondary battery, a current collecting member is generally welded to a tab of an electrode assembly. However, when the tab is welded to the current collecting member, the tab occupies a large space in the width direction, affecting the energy density.

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 that can reduce the space occupied by ears and improve energy density.

In order to accomplish the above object, the present invention provides a secondary battery including an electrode assembly, a case, a cap assembly, and a current collecting member. The electrode assembly is accommodated in the case and includes a main body portion and a first tab extending from one end of the main body portion in a length direction. The top cover assembly comprises a top cover plate and a first electrode terminal arranged on the top cover plate, and the top cover plate is connected to the shell. The current collecting member connects the first electrode terminal and the first tab. The current collecting member includes a substrate disposed at one side of the body portion in the length direction and perpendicular to the length direction, and a support plate. The base plate comprises a first part and a second part, and the second part is connected to one end, far away from the top cover plate, of the first part in the height direction. In the width direction, the edge of the second portion is recessed inward relative to the edge of the first portion and forms a notch. The support plate extends from an edge of the second portion near the notch and is folded back to a side of the second portion away from the main body portion. The first tab is connected to the support plate, and a portion of the first tab is located in the notch.

The projection of the first tab is located within the projection of the main body in a plane perpendicular to the longitudinal direction.

The edge of the first tab far away from the main body part does not exceed the edge of the second part far away from the notch.

In the width direction, the dimension of the second portion is larger than the dimension of the support plate.

The main body part is of a winding type structure, and a winding axis is parallel to the length direction. The main body portion includes a first region and a second region that are respectively located on both sides of the winding axis in the width direction. The junction of the second portion and the support plate is located on a side of the winding axis close to the first region in the width direction. The first tab comprises a plurality of first sub-tabs which are gathered towards the connection part of the second part and the supporting plate. At least a portion of the first plurality of sub-tabs extends from the first region.

Portions of the plurality of first sub-tabs extend from the second region, and a number of the first sub-tabs extending from the first region is greater than a number of the first sub-tabs extending from the second region.

The support plate is spaced from the first portion in the height direction.

The secondary battery further includes an insulating member at least partially adhered to a surface of the substrate near the main body portion.

The insulating member completely covers a surface of the substrate near the main body portion.

The current collecting member further includes a terminal connection plate perpendicular to the substrate and connecting the first electrode terminal and the substrate. A portion of the insulating member is also bonded to a surface of the terminal connecting plate near the main body portion.

The utility model has the advantages as follows: in this application, through setting up the breach, form in one side of second portion and dodge the space, and first utmost point ear can be via the surperficial laminating of keeping away from the base plate of breach and backup pad, is convenient for realize the welding. Meanwhile, the gap can accommodate a part of the first tab, so that the space occupied by the first tab in the width direction is reduced, and the energy density is improved.

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 fig. 2 at the circle box.

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

Fig. 5 is a cross-sectional view of the electrode assembly of fig. 4 taken along line a-a.

Fig. 6 is a sectional view of the electrode assembly of fig. 4 taken along line B-B.

FIG. 7 is a schematic view of an embodiment of a first pole piece of an electrode assembly in an expanded state.

Fig. 8 is a cross-sectional view of the first pole piece of fig. 7 taken along line C-C.

Fig. 9 is a schematic view of an embodiment of a current collecting member.

Fig. 10 is a schematic view of the current collecting member of fig. 9 before forming.

Fig. 11 is a schematic view of the electrode assembly and the current collecting member during assembly.

Fig. 12 is another schematic view of the electrode assembly and the current collecting member during assembly.

Fig. 13 is a schematic view of an embodiment of a current collecting member and an insulating member.

Fig. 14 is a cross-sectional view of the insulating member.

Fig. 15 is a schematic view of another embodiment of a current collecting member and an insulating member.

Wherein the reference numerals are as follows:

1 electrode Assembly

11 body part

111 first region

112 second region

12 first pole ear

121 first sub-tab

13 second ear

131 second sub-tab

14 first pole piece

141 first current collector

142 first active material layer

15 second pole piece

16 diaphragm

2 casing

3 Top cover assembly

31 ceiling board

32 first electrode terminal

33 second electrode terminal

4 current collecting component

41 substrate

411 first part

412 second part

42 support plate

421 bending part

422 connecting part

43 terminal connection board

5 insulating member

51 adhesive layer

52 insulating layer

G notch

L winding axis

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 a current collecting member 4.

The electrode assembly 1 is a core member of the secondary battery that realizes charge and discharge. Referring to fig. 4 and 5, the electrode assembly includes a first pole piece 14, a second pole piece 15, and a separator 16, the separator 16 separating the first pole piece 14 and the second pole piece 15.

In the present application, the electrode assembly 1 may be a winding type structure. The first pole piece 14, the second pole piece 15 and the diaphragm 16 are all in a band-shaped structure. The first pole piece 14, the separator 16, and the second pole piece 15 are sequentially laminated and wound along the winding axis L to form the electrode assembly 1. The electrode assembly 1 is flat. The winding axis L is substantially parallel to the length direction X.

Referring to fig. 7 and 8, the first electrode sheet 14 includes a first current collector 141 and a first active material layer 142 coated on a surface of the first current collector 141, and only a partial area of the first current collector 141 is coated with the first active material layer 142. The region of the first current collector 141 coated with the first active material layer 142 and the first active material layer 142 form a first coated region of the first pole piece 14, and the region of the first current collector 141 not coated with the first active material layer 142 forms a first uncoated region of the first pole piece 14. The first uncoated region may be plural.

Likewise, the second electrode sheet 15 includes a second current collector and a second active material layer coated on the surface of the second current collector, and only a partial area of the second current collector is coated with the second active material layer. Specifically, the region of the second current collector coated with the second active material layer and the second active material layer form a second coated region of the second pole piece 15, and the region of the second current collector uncoated with the second active material layer forms a second uncoated region of the second pole piece 15. The second uncoated region may be plural.

One of the first pole piece 14 and the second pole piece 15 is a positive pole piece, and the other of the first pole piece 14 and the second pole piece 15 is a negative pole piece. For the positive pole piece, the current collector can be an aluminum foil, and the active substance layer comprises a ternary material, lithium manganate or lithium iron phosphate. For the negative electrode plate, the current collector may be a copper foil, and the active material layer includes graphite or silicon.

The diaphragm 16 can be a Polyethylene (PE) film, a polypropylene (PP) film, a PP \ PE \ PP three-layer composite film.

Referring to fig. 4, the electrode assembly 1 of the present application includes a main body part 11, a first tab 12, and a second tab 13, from the external shape of the electrode assembly 1, the first tab 12 and the second tab 13 extending from both ends of the main body part 11 in the length direction X, respectively. The body portion 11 includes a first coated region, a separator 16, and a second coated region. The first tab 12 includes a plurality of first uncoated regions and the second tab 13 includes a plurality of second uncoated regions. After the electrode assembly 1 is wound, a plurality of first uncoated regions are laminated together and form the first tab 12, and a plurality of second uncoated regions are laminated together and form the second tab 13.

Referring to fig. 1, 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 of conductive metal. In some embodiments, the housing 2 is made of aluminum or an aluminum alloy.

The top cap assembly 3 includes a top cap plate 31, a first electrode terminal 32, and a second electrode terminal 33. The top cap plate 31 is disposed on the case 2 and covers the opening of the case 2, thereby enclosing the electrode assembly 1 within the case 2. The top cover plate 31 may be attached to the housing 2 by welding or the like. The first electrode terminal 32 and the second electrode terminal 33 are disposed on the top cover plate 31, and the first electrode terminal 32 is electrically connected to the first tab 12, and the second electrode terminal 33 is electrically connected to the second tab 13.

The number of the current collecting members 4 is two, one current collecting member 4 connects the first electrode terminal 32 and the first tab 12, and the other current collecting member 4 connects the second electrode terminal 33 and the second tab 13. The current collecting member 4 connected to the first tab 12 will be described in detail below.

The current collecting member 4 includes a substrate 41 and a support plate 42, the substrate 41 being disposed on one side of the body portion 11 in the longitudinal direction X and extending in a direction perpendicular to the longitudinal direction X. The substrate 41 is a flat plate substantially perpendicular to the longitudinal direction X. The base plate 41 and the support plate 42 are preferably integrally formed.

The base plate 41 includes a first portion 411 and a second portion 412, and the second portion 412 is connected to an end of the first portion 411 away from the top cover plate 31 in the height direction Z. In the width direction Y, the edge of the second portion 412 is recessed inward relative to the edge of the first portion 411 and forms a notch G. In some embodiments, the dimension of the second portion 412 in the width direction Y is smaller than the dimension of the first portion 41 in the width direction Y, and the notch G is formed on one side of the second portion 412 in the width direction Y.

The support plate 42 extends from an edge of the second portion 412 near the gap G and is folded back to a side of the second portion 412 away from the main body portion 11. The projection of the support plate 42 at least partially overlaps the projection of the second portion 412 in a plane perpendicular to the length direction X.

The first tab 12 is attached to the support plate 42, and a portion of the first tab 12 is located in the gap G.

Referring to fig. 10, before the electrode assembly 1 and the current collecting member 4 are assembled, the support plate 42 is bent such that the support plate 42 is substantially perpendicular to the base plate 41. Then, referring to fig. 11, the first tab 12 is attached to the support plate 42, and the first tab 12 and the support plate 42 are joined together by welding. Finally, referring to fig. 12, the support plate 42 is bent such that the support plate 42 is substantially parallel to the base plate 41, thereby reducing the space occupied by the support plate 42 and the first tab 12 in the length direction X and improving the energy density of the secondary battery.

If the edge of the second portion 412 connected to the support plate 42 is flush with the edge of the first portion 411 in the width direction Y, the first tab 12 may occupy an additional space in the width direction Y when the first tab 12 is welded to the support plate 42.

In the present application, by providing the notch G, an avoiding space is formed on one side of the second portion 412, and the first tab 12 can be attached to the surface of the support plate 42 away from the substrate 41 through the notch G, which is convenient for welding. Meanwhile, the gap G can accommodate a part of the first tab 12, so that the space occupied by the first tab 12 in the width direction Y is reduced, and the energy density is improved.

The support plate 42 includes a bent portion 421 and a connection portion 422, the bent portion 421 extends from an edge of the second portion 412 in the width direction Y and is bent into an arc shape, and the connection portion 422 extends from one end of the bent portion 421 away from the second portion 412. The first tab 12 is bent along the bent portion 421 and welded to the connection portion 422.

When the support plate 42 and the first tab 12 are bent, the bent portion 421 is formed at the bent portion of the support plate 42, so that the contact surface between the first tab 12 and the bent portion 421 is relatively smooth, thereby reducing the probability of the first tab 12 being punctured. Meanwhile, the first tab 12 is bent along the arc-shaped surface of the bending portion 421, so that the stress concentration of the first tab 12 at the bent position can be reduced, the first tab 12 is prevented from being broken, and the overcurrent capacity of the first tab 12 is ensured.

The projection of the first tab 12 is located within the projection of the body portion 11 in a plane perpendicular to the longitudinal direction X. This can prevent the first tab 12 from occupying extra space in the width direction Y, and also can reduce the risk of interference between the first tab 12 and the case 2 during the process of placing the electrode assembly 1 into the case 2.

Referring to fig. 12, if the edge of the first tab 12 remote from the body portion 11 exceeds the edge of the second portion 412 remote from the gap G, the area of the first tab 12 remote from the second portion 412 may be bent inward and inserted into the body portion 11, thereby causing a risk of short circuit. Thus, in some embodiments of the present application, the edge of the first tab 12 remote from the body portion 11 does not extend beyond the edge of the second portion 412 remote from the gap G.

The dimension of the second portion 412 is larger than the dimension of the support plate 42 in the width direction Y. Further, in a direction away from the notch G, an edge of the second portion 412 away from the bent portion 421 exceeds an edge of the connection portion 422 away from the bent portion 421. This prevents the support plate 42 from completely covering the second portion 412, reducing heat buildup between the second portion 412 and the support plate 42.

The main body 11 has a winding structure. Referring to fig. 5 and 6, the main body portion 11 includes a first region 111 and a second region 112, and the first region 111 and the second region 112 are respectively located on both sides of the winding axis L in the width direction Y. The junction of the second portion 412 and the support plate 42 is located on the side of the winding axis L close to the first region 111 in the width direction Y. That is, the first region 111 is closer to the junction of the second portion 412 and the support plate 42 than the second region 112.

The first tab 12 includes a plurality of first sub-tabs 121, and the plurality of first sub-tabs 121 are gathered toward the connection of the second portion 412 and the support plate 42. The first sub-tab 121 is a first uncoated region of the first pole piece 14. At least a portion of the plurality of first sub-tabs 121 extend from the first region 111. The first region 111 is closer to the connection between the second portion 412 and the support plate 42 than the second region 112, so that the distance between the first sub-tab 121 extending from the first region 111 and the support plate 42 is shorter, and when the plurality of first sub-tabs 121 are folded together, the dislocation between the plurality of first sub-tabs 121 is smaller, thereby reducing the requirement on the size of the first sub-tabs 121, saving space, and improving energy density.

Portions of the plurality of first sub-tabs 121 extend from the second region 112, and the number of first sub-tabs 121 extending from the first region 111 is greater than the number of first sub-tabs 121 extending from the second region 112. Compared to the scheme in which all the first sub-tabs 121 extend from the first region 111, extending the portions of the plurality of first sub-tabs 121 from the second region 112 may increase the distribution range of the first sub-tabs 121, improve the uniformity of heat distribution, reduce the temperature difference of the main body portion 11, improve the overcurrent capacity, reduce the internal resistance, reduce heat generation, and improve the cycle performance of the electrode assembly 1.

This application can make the junction of second portion 412 and backup pad 42 more be close to the middle part region that first sub-utmost point ear 121 distributes through setting up breach G, and then reduces the dislocation of a plurality of first sub-utmost point ears 121 in the in-process of drawing in, reduces the requirement to first sub-utmost point ear 121 size, saves space, improves energy density.

In the height direction Z, the support plate 42 is disposed spaced apart from the first portion 411. A gap is provided between the bent portion 421 of the support plate 42 and the first portion 411 in the height direction Z. By arranging the support plate 42 and the first portion 411 at an interval, bending after welding the first tab 12 and the support plate 42 can be easily achieved, stress concentration at the bent position is reduced in the bent state, and the risk of cracking of the current collecting member 4 is reduced.

In some embodiments, referring to fig. 13, the secondary battery further includes an insulating member 5, and the insulating member 5 is at least partially adhered to a surface of the substrate 41 near the body portion 11. The insulating member 5 can avoid the body portion 11 from contacting the substrate 41, thereby reducing the risk of short circuits.

The insulating member 5 has a multilayer structure. Referring to fig. 14, the insulating member 5 includes an adhesive layer 51 and an insulating layer 52, and the adhesive layer 51 adheres the insulating layer 52 to the surface of the substrate 41 close to the main body portion 11. The insulating layer 52 may be made of an insulating and heat-insulating material. Specifically, the insulating layer 52 may be an organic material, such as PP, PET; the insulating layer 52 may also be an inorganic material such as alumina, silicon dioxide, aluminum silicate, zirconium oxide, or the like. The adhesive layer 51 may be an acrylic adhesive.

The current collecting member 4 generates heat and increases temperature during the charge and discharge of the secondary battery. And the insulating member 5 can reduce the influence of the current collecting member 4 on the temperature rise of the main body portion 11, improving the cycle performance of the electrode assembly 1.

The insulating member 5 completely covers the surface of the substrate 41 near the main body portion 11 to completely separate the substrate 41 and the main body portion 11, reducing the risk of short circuits.

In some embodiments, the current collecting member 4 further includes a terminal connection plate 43, the terminal connection plate 43 being perpendicular to the substrate 41 and connecting the first electrode terminal 32 and the substrate 41. The terminal connection plate 43 may be connected to the first electrode terminal 32 by welding. The substrate 41 may be bent downward from one end of the terminal connection plate 43 in the longitudinal direction X. The base plate 41, the support plate 42, and the terminal connection plate 43 are integrally formed.

In some embodiments, referring to fig. 15, the insulating member 5 includes a first region adhered to the surface of the substrate 41 near the body portion 11 and a second region adhered to the surface of the terminal connection plate 43 near the body portion 11. The second region of the insulating member 5 may separate the terminal connecting plate 43 from the main body portion 11, thereby reducing the risk of short circuits. The first region and the second region can be integrally arranged or can be two independent sheets.

Claims

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

the electrode assembly (1) is accommodated in the shell (2) and comprises a main body part (11) and a first tab (12), wherein the first tab (12) extends from one end of the main body part (11) along the length direction (X);

the top cover assembly (3) comprises a top cover plate (31) and a first electrode terminal (32) arranged on the top cover plate (31), and the top cover plate (31) is connected to the shell (2);

the current collecting component (4) is connected with the first electrode terminal (32) and the first electrode lug (12);

the current collecting member (4) includes a substrate (41) and a support plate (42), the substrate (41) being disposed on one side of the body portion (11) in the longitudinal direction (X) and perpendicular to the longitudinal direction (X);

the base plate (41) comprises a first part (411) and a second part (412), and the second part (412) is connected to one end, away from the top cover plate (31), of the first part (411) in the height direction (Z);

in the width direction (Y), the edge of the second part (412) is recessed inwards relative to the edge of the first part (411) and forms a notch (G);

the supporting plate (42) extends from the edge of the second part (412) close to the notch (G) and is folded back to the side of the second part (412) far away from the main body part (11);

the first tab (12) is connected to the support plate (42), and a portion of the first tab (12) is located in the gap (G).

2. The secondary battery according to claim 1, wherein a projection of the first tab (12) is located within a projection of the main body portion (11) in a plane perpendicular to the length direction (X).

3. The secondary battery according to claim 1, wherein an edge of the first tab (12) away from the main body portion (11) does not exceed an edge of the second portion (412) away from the notch (G).

4. The secondary battery according to claim 1, wherein a dimension of the second portion (412) is larger than a dimension of the support plate (42) in the width direction (Y).

5. The secondary battery according to claim 1,

the main body part (11) is of a winding type structure, and the winding axis is parallel to the length direction (X);

the main body part (11) comprises a first area (111) and a second area (112), wherein the first area (111) and the second area (112) are respectively positioned on two sides of the winding axis along the width direction (Y);

the junction of the second portion (412) and the support plate (42) is located on the side of the winding axis close to the first region (111) in the width direction (Y);

the first pole lug (12) comprises a plurality of first sub-pole lugs (121), and the plurality of first sub-pole lugs (121) are gathered towards the connection part of the second part (412) and the supporting plate (42);

at least part of the plurality of first sub-tabs (121) extends from the first region (111).

6. The secondary battery according to claim 5, wherein portions of the plurality of first sub-tabs (121) extend from the second region (112), and the number of first sub-tabs (121) extending from the first region (111) is greater than the number of first sub-tabs (121) extending from the second region (112).

7. The secondary battery according to claim 1, wherein the support plate (42) is disposed spaced apart from the first portion (411) in the height direction (Z).

8. The secondary battery according to claim 1, further comprising an insulating member (5), wherein the insulating member (5) is at least partially adhered to a surface of the substrate (41) adjacent to the main body portion (11).

9. The secondary battery according to claim 8, wherein the insulating member (5) completely covers a surface of the substrate (41) near the main body portion (11).

10. The secondary battery according to claim 8,

the current collecting member (4) further includes a terminal connection plate (43), the terminal connection plate (43) being perpendicular to the substrate (41) and connecting the first electrode terminal (32) and the substrate (41);

a part of the insulating member (5) is also bonded to the surface of the terminal connecting plate (43) close to the main body (11).