CN109698385A

CN109698385A - Secondary battery

Info

Publication number: CN109698385A
Application number: CN201710997124.5A
Authority: CN
Inventors: 周勇; 蔡如来; 王鹏; 李想
Original assignee: Contemporary Amperex Technology Co Ltd
Current assignee: Contemporary Amperex Technology Co Ltd
Priority date: 2017-10-20
Filing date: 2017-10-20
Publication date: 2019-04-30
Anticipated expiration: 2037-10-20
Also published as: CN109698385B

Abstract

The present invention provides a secondary battery, which includes an electrode assembly and a top cover assembly disposed above the electrode assembly. The electrode assembly includes a main body and a first tab protruding from the main body, the first tab has: a first connecting part, which is fixed on the top cover assembly; and a first bending part, which is bent downward relative to the first connecting part and is connected between the main body and the first connecting part. The secondary battery further includes a first patch, the first patch has: a first support part attached to the lower side of the first connection part; and a second support part bent downward with respect to the first support part and Paste it on the inside of the first bending part. The thickness of the first patch is 0.1 mm to 5 mm, and the Young's modulus of elasticity is 1000 MPa to 10000 MPa. There will be a large force at the bend where the first support part and the second support part are connected, and the first support part supports the first connection part of the first tab upward under the action of the force, so that the first The shape of the tabs is fixed.

Description

Secondary cell

Technical field

The present invention relates to field of batteries more particularly to a kind of secondary cells.

Background technique

Secondary cell generally includes electrode assembly, cap assembly and shell, and electrode assembly usually passes through tab and top cover Component connection, and electrode assembly needs to be put into shell after connecting with cap assembly.In order to improve the energy density of secondary cell, pole Ear needs to bend to reduce its space occupied.But since tab itself is very thin and flexible easy to crack, tab is being folded over It is easy to crack in journey, if do not fixed and supported tab, tab is easy to be pressed into electrode group by cap assembly The main body (main body includes positive electrode, negative electrode and isolation film) of part, so as to cause short circuit.The prior art is usually in pole Adhesive tape is attached on ear to avoid short circuit, but adhesive tape is soft, can not prevent the main body that electrode assembly is inserted into when lug bending.Separately Outside, the prior art also avoids short circuit by the way that backing plate is arranged between cap assembly and the main body of electrode assembly, but backing plate is pacified It is big to fill complex process, occupied space, meanwhile, in order to realize the installation of backing plate, backing plate is typically only capable to a part of support tab, according to The main body of electrode assembly is inserted into when not can avoid lug bending so.

Summary of the invention

In view of the problems in the background art, the purpose of the present invention is to provide a kind of secondary cell, it is avoided that pole Ear is inserted into the main body of electrode assembly, prevents short circuit, improves the security performance of secondary cell.

To achieve the goals above, the present invention provides a kind of secondary cells comprising electrode assembly and is set to electricity Cap assembly above the component of pole.Electrode assembly includes main body and the first tab stretched out from main body, and the first tab includes First connecting portion is fixed on cap assembly；And first bending part, it is bent downward relative to first connecting portion and is connected to master Between body and first connecting portion.The secondary cell further includes the first patch, and the first patch includes the first support portion, is pasted on The downside of first connecting portion；And second support portion, it is bent downward relative to the first support portion and is pasted on the first bending part Inside.Wherein, the first patch with a thickness of 0.1mm~5mm, Young's modulus of elasticity is 1000MPa~10000MPa.

Beneficial effects of the present invention are as follows:

In the secondary battery in accordance with the present invention, the first patch is as deformation occurs after the first lug bending, but due to First patch with a thickness of 0.1mm~5mm and Young's modulus of elasticity is 1000MPa~10000MPa, therefore the first support portion The bending place connected with the second support portion can have biggish active force, and the first support portion is upward under the action of the active force The first connecting portion of the first tab is supported, to be fixed to the shape of the first tab.Since the first support portion can be under Collateral support first connecting portion, therefore, when cap assembly pushes the first tab, the first support portion can be inserted into avoid the first tab Into the main body of electrode assembly, short circuit is prevented, improves the security performance of secondary cell.

Detailed description of the invention

Fig. 1 is a schematic diagram of the secondary cell according to the present invention in forming process, wherein the first tab is not turned under Folding.

Fig. 2 is a cross-sectional view of the secondary cell of Fig. 1.

Fig. 3 is another schematic diagram of the secondary cell of Fig. 1, and one of electrode assembly, the first patch and the second patch save Slightly.

Fig. 4 is secondary cell according to the present invention schematic diagram after molding.

Fig. 5 is the exploded view of Fig. 4.

Fig. 6 is a cross-sectional view of Fig. 4.

Fig. 7 is a schematic diagram of cap assembly in Fig. 4.

Wherein, the reference numerals are as follows:

1 electrode assembly, 211 liquid injection hole

11 main body, 22 first electrode terminal

111 upper surface, 23 first connection sheet

12 first tab, 3 first patch

121 first connecting portion, 31 first support portion

122 first bending part, 32 second support portion

13 second tab, 33 third support portion

131 second connecting portions 4 weld screening glass

132 second bending part, 5 second patch

The 4th support portion of 2 cap assembly 51

The 5th support portion of 21 coping plate 52

Specific embodiment

Carry out the secondary cell that the present invention will be described in detail with reference to the accompanying drawings.

The noun of locality (such as top, downside and inside) occurred in present invention description is the direction shown in Fig. 4~6.

Referring to fig. 4 to fig. 6, secondary cell according to the present invention includes electrode assembly 1 and is set to above electrode assembly 1 Cap assembly 2.Electrode assembly 1 is included including main body 11 and the first tab 12 stretched out from main body 11, the first tab 12 First connecting portion 121 is fixed on cap assembly 2；And first bending part 122, it is bent downward simultaneously relative to first connecting portion 121 And it is connected between main body 11 and first connecting portion 121.The secondary cell further includes the first patch 3, and the first patch 3 includes First support portion 31, is pasted on the downside of first connecting portion 121；And second support portion 32, relative to the first support portion 31 to Lower bending and the inside for being pasted on the first bending part 122.Wherein, the first patch 3 with a thickness of 0.1mm~5mm, Young elasticity Modulus is 1000MPa~10000MPa.Further, the thickness of the first patch 3 is preferably 0.5mm~2.5mm, Young springform Amount is preferably 4000MPa~6000MPa.The PET etc. of electrolyte resistance corrosion can be selected in the material of first patch 3.

The main body 11 of electrode assembly 1 includes opposite polarity first electrode, second electrode and by first electrode and second The isolation film that electrode separates.First electrode, second electrode and isolation film can be winding-structure, can also be stepped construction.First pole Ear 12 can be cut by first electrode, and the first tab 12 of each electrode assembly 1 can be the multilayered structure welded together.When So, the first tab 12 can also be the individual components for being welded in first electrode.

The secondary cell further includes shell (not shown), and electrode assembly 1 is contained in shell, and cap assembly 2 and shell Body connection, electrode assembly 1 is sealed in shell.

First cap assembly 2 and electrode assembly 1 are horizontally disposed with, together referring to Fig. 3 when assembling secondary cell of the invention When the first tab 12 is horizontally fixed on cap assembly 2, then, referring to Figures 1 and 2, in the surface mount of the first tab 12 First patch 3；Finally, bending the first tab 12 referring to fig. 4 to fig. 6 electrode assembly 1 to be folded into the lower section of cap assembly 2. First connecting portion 121 is formed after the bending of first tab 12 and the first bending part 122, the first patch 3 are bent with the first tab 12 And form corresponding first support portion 31 and the second support portion 32.

In the secondary battery in accordance with the present invention, deformation occurs after the first patch 3 is bent with the first tab 12, but by It is 1000MPa~10000MPa in the Young's modulus of elasticity of the first patch 3, therefore the first support portion 31 and the second support portion 32 connect The bending place connect can have biggish active force, and the first support portion 31 supports the first tab upwards under the action of the active force 12 first connecting portion 121, to be fixed to the shape of the first tab 12.Due to the first support portion 31 can under it is collateral First connecting portion 121 is supportted, therefore, when cap assembly 2 pushes the first tab 12, the first support portion 31 can be to avoid the first tab 12 are inserted into the main body 11 of electrode assembly 1, prevent short circuit, improve the security performance of secondary cell.

Referring to figure 5 and figure 6, the first patch 3 may also include the third support portion 33 for being pasted on the upper surface 111 of main body 11, Second support portion 32 is connected between the first support portion 31 and third support portion 33.The first patch had both can be improved in third support portion 33 The integral strength of piece 3, while the first connecting portion 121 of the first tab 12 and the upper surface 111 of main body 11 can also be separated.

Referring to Fig. 4 to Fig. 7, cap assembly 2 includes coping plate 21 and the first electrode terminal 22 for being set to coping plate 21, And first connecting portion 121 is electrically connected to first electrode terminal 22.First electrode terminal 22 may pass through coping plate 21 and be projected into top 21 upside of cover plate, in order to be connect with external other components.

Referring to figure 5 and figure 6, cap assembly 2 further includes the first connection sheet 23, is connected to first connecting portion 121 and the first electricity Between extreme son 22；First support portion 31 is located at the downside of the first connection sheet 23 and the first connection sheet 23 of covering.In order to save sky Between, improve the energy density of secondary cell, the distance between upper surface 111 of the first connection sheet 23 and main body 11 very little, therefore, When shaking in the use process of secondary cell, the first connection sheet 23 is easy to the upper surface 111 of contact main body 11 and leads Cause short circuit.It, can be effectively by the first connection sheet 23 and main body by the first support portion 31 of setting the first connection sheet 23 of covering 11 upper surface 111 separates, and avoids short circuit, improves the security performance of secondary cell.

Referring to Fig. 3 and Fig. 6, the secondary cell further include: welding screening glass 4 is fixed on 121 downside of first connecting portion, First support portion 31 is located at the downside of welding screening glass 4 and covering welding screening glass 4.Welding screening glass 4 can be in welding process The first tab 12 of middle protection and the bonding strength for improving first connecting portion 121 and the first connection sheet 23.

Due in the assembling process of electrode assembly 1 and cap assembly 2, needing using multi-pass welding process, therefore also Various particles can be generated, and the first patch 3 can adsorb the particle that welding generates to a certain extent, and particle is avoided to fall into main body 11, reduce various risks caused by particle.

Referring to Fig. 3 to Fig. 7, coping plate 21 has liquid injection hole 211；First support portion 31 of the first patch 3 extends to fluid injection The downside in hole 211.When injecting electrolyte into the shell of secondary cell by liquid injection hole 211, if electrolyte directly washes away Main body 11 (the especially isolation film of main body 11), it is easy to cause 1 low-voltage of electrode assembly, short circuit, K value relatively low (unit time Interior voltage drop).And since the first support portion 31 of the first patch 3 extends to the downside of liquid injection hole 211, it can be with first Support portion 31 can directly wash away main body 11 to avoid electrolyte, improve performance and the service life of secondary cell.

First patch 3 is equipped with insulating cement close to the surface of the side of the first tab 12.That is, the first patch 3 passes through Insulating cement pastes on the first tab 12.Meanwhile insulating cement additionally aids the particle that absorption welding is formed.

Referring to fig. 4 to fig. 6, electrode assembly 1 is multiple, 1 through-thickness of multiple electrodes component arrangement, and the multiple electricity All first tab, 12 through-thickness of pole component 1 form two groups.First tab 12 of each group is adjacent to each other and is fixed on one It rises.First support portion, 31 through-thickness extends and covers the first connecting portion 121 of two group of first tab 12 simultaneously；Second support Portion 32 is two, through-thickness, and two the second support portions 32 are located at the two sides of the first support portion 31, and each second support Portion 32 is pasted on the inside of the first bending part 122 of corresponding one group of first tab 12.Referring to figure 5 and figure 6, first patch 3 The first tab 12 of multiple electrodes component 1 can be covered simultaneously, so as to effectively simplify barbola work, improved efficiency.

Further, referring to figure 5 and figure 6, the first patch 3 may also include two third support portions 33, each third support portion 33 are pasted on the upper surface 111 of main body 11 and are connected with corresponding second support portion 32, and the first support portion 31, the second support portion 32 and third support portion 33 be integrally formed.

Referring to Fig. 5, electrode assembly 1 further includes the second tab 13 stretched out from main body 11, and the second tab 13 includes second Interconnecting piece 131 is fixed on cap assembly 2；And second bending part 132, it bends downward and connects relative to second connecting portion 131 Between main body 11 and second connecting portion 131.The secondary cell further includes the second patch 5, and the second patch 5 includes the 4th Support part 51 is pasted on the downside of second connecting portion 131；And the 5th support portion 52, it is bent downward relative to the 4th support portion 51 And it is pasted on the inside of the second bending part 132；Wherein, the second patch 5 with a thickness of 0.1mm~5mm, Young's modulus of elasticity is 1000MPa~10000MPa.

The structure and function of second patch 5 is identical as the first patch 3.Four support portions 51 of the second patch 5 can be to avoid Two tabs 13 are inserted into the main body 11 of electrode assembly 1, prevent short circuit, improve the security performance of secondary cell.

Claims

1. A secondary battery, comprising an electrode assembly (1) and a top cover assembly (2) disposed above the electrode assembly (1);

The electrode assembly (1) comprises a main body (11) and a first tab (12) protruding from the main body (11), the first tab (12) having:

a first connecting portion (121) fixed to the top cover assembly (2); and

the first bending part (122) is bent downward relative to the first connecting part (121) and is connected between the main body (11) and the first connecting part (121);

It is characterized in that,

The secondary battery further comprises a first patch (3), the first patch (3) having:

the first support part (31), which is pasted on the lower side of the first connection part (121); and

The second support portion (32) is bent downward relative to the first support portion (31) and is pasted on the inner side of the first bent portion (122);

Wherein, the thickness of the first patch (3) is 0.1 mm to 5 mm, and the Young's modulus of elasticity is 1000 MPa to 10000 MPa.

2 . The secondary battery according to claim 1 , wherein the first patch ( 3 ) further comprises a third support portion ( 33 ) adhered to the upper surface ( 111 ) of the main body ( 11 ), and the second support The part (32) is connected between the first support part (31) and the third support part (33).

3. The secondary battery according to claim 1, wherein the top cover assembly (2) comprises a top cover sheet (21) and a first electrode terminal (22) provided on the top cover sheet (21), and the A connecting portion (121) is electrically connected to the first electrode terminal (22).

4. The secondary battery according to claim 3, wherein

The top cover assembly (2) further comprises a first connecting piece (23) connected between the first connecting portion (121) and the first electrode terminal (22);

The first support portion (31) is located on the lower side of the first connecting piece (23) and covers the first connecting piece (23).

5 . The secondary battery according to claim 4 , wherein the secondary battery further comprises: a welding protection sheet ( 4 ) fixed on the lower side of the first connecting portion ( 121 ), the first supporting portion ( 31 ). 6 . ) is located on the lower side of the welding protection sheet (4) and covers the welding protection sheet (4).

6. The secondary battery according to claim 3, wherein

The top cover sheet (21) has a liquid injection hole (211);

The first support part (31) of the first patch (3) extends to the lower side of the liquid injection hole (211).

7 . The secondary battery according to claim 1 , wherein the surface of the side of the first patch ( 3 ) close to the first tab ( 12 ) is provided with insulating glue. 8 .

8. The secondary battery according to claim 1, wherein

There are multiple electrode assemblies (1), the multiple electrode assemblies (1) are arranged along the thickness direction, and all the first tabs (12) of the multiple electrode assemblies (1) form two groups along the thickness direction;

The first support portion (31) extends along the thickness direction and simultaneously covers the first connecting portions (121) of the two sets of first tabs (12);

There are two second support parts (32), and along the thickness direction, the two second support parts (32) are respectively located on both sides of the first support part (31), and each second support part (32) is pasted on a corresponding one The inner side of the first bent portion (122) of the first tab (12) of the group.

9 . The secondary battery according to claim 8 , wherein the first patch ( 3 ) further comprises two third support parts ( 33 ), and each third support part ( 33 ) is attached to the main body ( 11 ) The upper surface (111) is connected with the corresponding second support portion (32), and the first support portion (31), the second support portion (32) and the third support portion (33) are integrally formed.

10. The secondary battery according to claim 1, wherein

The electrode assembly (1) further comprises a second tab (13) protruding from the main body (11), the second tab (13) having: a second connecting portion (131) fixed to the top cover assembly (2); and a second bending portion (132), which is bent downward relative to the second connecting portion (131) and is connected between the main body (11) and the second connecting portion (131);

The secondary battery further comprises a second patch (5), the second patch (5) has: a fourth support part (51), which is attached to the lower side of the second connection part (131); and a fifth support part (52), bent downward relative to the fourth support part (51) and pasted on the inner side of the second bending part (132); wherein, the thickness of the second patch (5) is 0.1mm-5mm, Young's The elastic modulus is 1000MPa to 10000MPa.