WO2018199439A1

WO2018199439A1 - Rechargeable battery

Info

Publication number: WO2018199439A1
Application number: PCT/KR2018/001102
Authority: WO
Inventors: 김유나
Original assignee: 삼성에스디아이 주식회사
Priority date: 2017-04-25
Filing date: 2018-01-25
Publication date: 2018-11-01
Also published as: KR102444273B1; KR20180119365A

Abstract

A rechargeable battery according to an embodiment of the present invention comprises: a case for receiving an electrode assembly; a cap plate coupled to an opening of the case; an electrode terminal arranged on the cap plate; a reinforcing plate connected, through second welding, to uncoated part tabs which are drawn out from the electrode assembly and are connected to each other through first welding; and a connection tab connected to the reinforcing plate through third welding at one side thereof and connected to the electrode terminal at the other side thereof.

Description

Secondary battery

The present disclosure relates to a secondary battery, and more particularly, to a secondary battery that connects a plurality of plain tabs drawn from an electrode substrate of an electrode assembly to an electrode terminal using a connection tab.

A rechargeable battery is a battery that repeatedly performs charging and discharging, unlike a primary battery. Small capacity secondary batteries can be used in portable electronic devices such as mobile phones, notebook computers and camcorders, and large capacity secondary batteries can be used as power sources for driving motors of hybrid vehicles and electric vehicles.

For example, the secondary battery includes an electrode assembly for charging and discharging, a case accommodating the electrode assembly, a cap plate coupled to the opening of the case, and an electrode terminal electrically connected to the electrode assembly and drawn out of the cap plate. do.

According to the demand of high power and high capacity, the electrode assembly forms a plurality of plain tabs. Multiple uncoated taps lower the resistance for high power. The plain tabs are connected to the connection tabs, and the connection tabs are connected to the electrode terminals.

For example, the plain tabs are laser welded after ultrasonic welding to the connecting tab. At this time, as the number of the tabs of the plain tabs increases, the stack height of the tabs of the tab tabs increases. Therefore, during ultrasonic welding of the plain tabs and the connecting tab, the ultrasonic power output is high.

Due to this, the plain tabs may be damaged. In ultrasonic welding, in the case of laser welding damaged plain tabs to the connection tabs, welding uniformity and welding reliability may be degraded.

One aspect of the present invention is to provide a secondary battery that improves welding uniformity and welding reliability for flat tabs and connecting tabs.

According to an exemplary embodiment of the present invention, a secondary battery includes a case accommodating an electrode assembly, a cap plate coupled to an opening of the case, an electrode terminal provided on the cap plate, and a plain part drawn out of the electrode assembly and first welded thereto. And a reinforcing plate second welded to the tabs, and a connecting tab connected to the electrode terminal at the other end by being third welded to the reinforcement plate.

The first welding may temporarily weld the plurality of plain tabs by ultrasonic welding, and the second welding may be main welding of the reinforcing plate to the welded plain tabs by ultrasonic welding.

The third welding may connect the connecting tab to the welded plain tabs and the reinforcing plate by laser welding.

The second welded plain tabs and the reinforcing plate are first welded welded outwardly from the horn and anvil to a first knurl portion of the first planar area, and a first planar area inside the first welded area. And a second null weld that is ultrasonically welded to the second null portion of the smaller second planar area.

The first null weld may be ultrasonically welded to a first depth of the first null portion, and the second null weld may be ultrasonically welded to a second depth of the second null portion that is shallower than the first depth.

The reinforcement plate may be disposed on one or both sides of the tack-welded tabs.

The second null weld may be formed in the entire width direction of the plain tabs.

The second null weld may be formed at a center portion in the width direction of the plain tabs.

The secondary battery according to an embodiment of the present invention further includes an insulating member disposed between the electrode assembly and the cap plate and coupled to the cap plate, wherein the insulating member is formed by the tab of the plain tabs from the electrode assembly. A first cutout opening the draw toward the cap plate, and a second cutout opening the process of welding the plain tabs and the reinforcing plate to the connection tab.

The electrode terminal includes a first terminal installed in an insulating structure on the cap plate, and a second terminal electrically connected to the cap plate, wherein the second terminal is connected to a first protrusion protruding to an outer surface of the cap plate. The connection tab which is coupled and welded and electrically connected to the second terminal may be coupled and welded to a second protrusion protruding to an inner surface of the cap plate.

According to an embodiment of the present invention, the first tabs (eg, ultrasonic welding) on the plain tabs are welded to the second plate (eg, ultrasonic welding) on the reinforcing plate, and then the connection tabs are removed from the reinforcing plates. 3 Welding (eg, laser welding) can improve weld uniformity and weld reliability for the flat tabs and connecting tabs.

In the second welding (ultrasound main welding), the tabs and the reinforcing plate are welded with the first and second null welds having different first and second planar areas, and the second null weld with a small second planar area. The third welding (laser welding) of the connection tabs can further improve the welding uniformity and welding reliability for the plain tabs and the connection tabs.

1 is a perspective view of a rechargeable battery according to an exemplary embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1.

3 is a cross-sectional view taken along line III-III of FIG. 1.

FIG. 4 is a perspective view illustrating ultrasonically welded states of the tabs of the uncoated region of the electrode assembly of FIG. 3.

5 is a perspective view of the ultrasonic main welding state by applying a reinforcing plate to the uncoated region tabs ultrasonically welded.

Fig. 6 is a sectional view of the horn and the anvil used for the ultrasonic main welding.

7 is a perspective view of a state in which the ultrasonic main welded plain tabs and the reinforcing plate are laser welded to the connecting tab.

FIG. 8 is a front view showing a first embodiment of the state in which the plain tabs and the reinforcing plate are ultrasonically welded in a state and after the main welding, they are laser welded to the connecting tab.

Fig. 9 is a front view showing a second embodiment of the state in which the plain tabs and the reinforcing plate are ultrasonically welded to the connecting tab and laser welded to the connecting tab after the main welding.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like elements throughout the specification.

In addition, since the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of description, the present invention is not necessarily limited to the illustrated.

Throughout the specification, when a part is "connected" to another part, it includes not only "directly connected", but also "indirectly connected" between other members. In addition, when a part is said to "include" a certain component, this means that it may further include other components, except to exclude other components unless otherwise stated.

1 is a perspective view of a rechargeable battery according to an exemplary embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1. 1 and 2, a rechargeable battery according to an embodiment may include a case 20 accommodating an electrode assembly 10 for charging / discharging and a cap plate coupled to an opening 21 of the case 20. 30 and an electrode terminal (eg, the first terminal 41 and the second terminal 42) provided at the cap plate 30 and electrically connected to the electrode assembly 10.

The case 20 sets a space for accommodating the electrode assembly 10 and the electrolyte in the shape of a plate (see FIG. 4). For example, the case 20 is formed in a substantially rectangular parallelepiped space and has a rectangular opening 21 at one side thereof to insert the electrode assembly 10.

The cap plate 30 is coupled to the opening 21 of the case 20 to seal the opening of the case 20. As an example, the case 20 and the cap plate 30 may be made of aluminum and welded to each other at the opening 21. The first terminal 41 is installed in the cap plate 30 in an insulating structure, and the second terminal 42 is installed in a structure electrically connected to the cap plate 30 to form a cap assembly.

An insulating member 70 is disposed between the electrode assembly 10 and the cap plate 30. The insulating member 70 is formed of an electrical insulating material and fixedly coupled to the upper cap plate 30 to electrically insulate the electrode assembly 10 and the cap plate 30. In addition, the insulating member 70 enables electrical connection between the electrode assembly 10 and the first and

second terminals

41 and 42.

The cap plate 30 further includes an electrolyte injection hole 31 and a vent hole 32. The electrolyte injection hole 31 couples the cap plate 30 to the case 20 to weld the electrolyte, and then injects the electrolyte into the case 20. After the electrolyte injection, the electrolyte injection opening 31 is sealed with a sealing stopper 311.

The vent hole 32 is formed to discharge the internal pressure by the gas generated inside the secondary battery by the charging and discharging action of the electrode assembly 10, and is sealed by the vent plate 321. For example, the vent hole 32 and the vent plate 321 may be integrally formed with the cap plate 30 through a coining process.

When the internal pressure of the secondary battery reaches the set pressure, the vent plate 321 is cut to open the vent hole 32 to discharge the gas and the internal pressure generated by the overcharge. To this end, the vent plate 321 has a notch 322 for inducing incision.

3 is a cross-sectional view taken along line III-III of FIG. 1, and FIG. 4 is a perspective view illustrating ultrasonic welding of the tabs of the uncoated region of the electrode assembly of FIG. 3. 3 and 4, the electrode assembly 10 is formed in a plate shape that forms a semicircle plane (xy plane) at both ends in the y-axis direction so as to be accommodated in the case 20 having a substantially rectangular parallelepiped shape.

The electrode assembly 10 includes a first electrode 11 (for example, a cathode) and a second electrode 12 (for example, an anode) provided on both sides of the separator 13, which is an electrical insulation material, and the cathode 11. ), The separator 13 and the positive electrode 12 are wound. In addition, the electrode assembly may be formed in a stacked structure (not shown).

Well, the

anodes

11 and 12 are the electrode bases of the metal foils (for example, Cu and Al foils), that is, the

coating portions

111 and 121 in which the active material is applied to the current collector, and the house exposed by not applying the active material. It includes a plurality of plain tabs (112, 122) formed as a whole. The

plain tabs

112 and 122 are disposed at one end of the electrode assembly 10.

That is, the plain tabs 112 of the negative electrode 11 are disposed at one side (the right side of FIG. 4) at one end (the top of FIG. 4) of the electrode assembly 10, and the plain tabs 122 of the positive electrode 12 are Spaced apart from the same end of the electrode assembly 10 (top of Figure 4) is disposed on each other on the other side (left of Figure 4).

In addition, the plurality of

non-coating tabs

112 and 122 are provided in the electrode assembly 10 so as to allow a current to be charged and discharged, thereby reducing the overall current resistance of the

non-coating tabs

112 and 122. Accordingly, the electrode assembly 10 may charge and discharge a high current through the

tabs

112 and 122.

Referring to FIG. 4, the

tabs

112 and 122 drawn out from the electrode assembly 10 are stacked on each other to be first welded W1. The first welding W1 welds the plurality of

plain tabs

112 and 122 to each other by ultrasonic welding. Therefore, the

negative tabs

112 and 122 of the positive and

negative electrodes

11 and 12 are kept in close contact with each other without being separated into sheets, so that they can have low electrical conductivity.

The first welding W1 is ultrasonically welded to align the

plain tabs

112 and 122 forming the stacked structure of the multi-tabs at positions corresponding to each other in the stacking direction. Therefore, during the second welding W2 (ultrasound main welding) that is performed after the tack welding, the

tabs

112 and 122 are not separated into sheets. Accordingly, damage to the

uncoated tabs

112 and 122 by the horn 71 and the anvil 72 can be prevented.

5 is a perspective view of the ultrasonic main welding state by applying a reinforcing plate to the uncoated region tabs ultrasonically welded. Referring to FIG. 5, the welded

plain tabs

112 and 122 are second welded with the reinforcing

plates

113 and 123. The second welding W2 main-welds the

plain tabs

112 and 122 and the reinforcing

plates

113 and 123 by ultrasonic welding.

Fig. 6 is a sectional view of the horn and the anvil used for the ultrasonic main welding. 5 and 6, the reinforcing

plates

113 and 123 have a higher mechanical rigidity than the

plain tabs

112 and 122, and in contact with the horn 71 and the anvil 72 during ultrasonic main welding, Protect the

tabless tabs

112, 122.

That is, in the case of ultrasonic main welding, as the thicknesses of the

tabs

112 and 122 become thicker, the height of the knurl in the horn 71 and the anvil 72 increases, and thus the ultrasonic output increases. Despite this, in the ultrasonic main welding, the reinforcing

plates

113 and 123 may prevent damage to the

plain tabs

112 and 122.

The reinforcing

plates

113 and 123 prevent crack-like damage to the

plain tabs

112 and 122, thereby improving the weldability and welding reliability of the ultrasonic main welding to the

plain tabs

112 and 122. FIG. In addition, the welding reliability of the reinforcing

plates

113 and 123 and the

plain tabs

112 and 122 is improved.

For example, the horn 71 and the anvil 72 used for the ultrasonic main welding are the

first knurled portions

711 and 721 of the first planar area, and the second knurled part of the second planar area smaller than the first planar area. 712, 722. The first and second planar areas mean the yz plane area (refer to FIGS. 8 and 9) set by the unit nulls of the first and second

null portions

711, 721; 721, 722.

Referring to FIG. 2 again, the rechargeable battery of the exemplary embodiment includes connecting

tabs

51 and 52 connecting the reinforcing

plates

113 and 123 and the electrode terminals (the first and second terminals 41 and 42). The

connection tabs

51 and 52 electrically connect the first and

second terminals

41 and 42 to the

plain tabs

112 and 122 of the electrode assembly 10.

The first terminal 41 is installed in the terminal hole H1 of the cap plate 30 and is connected to the rivet terminal 411 and the terminal plate electrically connected to the rivet terminal 411. 412).

An external insulation member 61 is interposed between the outer surface of the cap plate 30 and the terminal plate 412, and an internal insulation member 62 is interposed between the inner surface of the cap plate 30 and the connection tab 51. A gasket 63 is interposed between the terminal hole H1 of the cap plate 30 and the rivet terminal 411.

The rivet terminal 411 penetrates through the outer insulation member 61 and the terminal plate 412 at the outer surface side of the cap plate 30, and the inner insulation member 62 and the connection tabs at the inner surface side of the cap plate 30 ( Penetrates 51).

By caulking or welding the outside of the penetrating rivet terminal 411 and the periphery of the terminal plate 412 and the inside of the penetrating rivet terminal 411 and the connecting tab 51, the rivet terminal 411 is connected to the terminal. It is fixed to the plate 412.

As a result, the first terminal 41 and the connection tab 51 are installed in the cap plate 30 with an electrical insulating structure through the inner and inner insulating members 61 and 62 and are connected to the negative electrode 11. The gasket 63 electrically insulates the cap plate 30 and the rivet terminal 411 and seals between the rivet terminal 411 and the terminal hole H1.

The second terminal 42 is coupled to and welded to the first protrusion 331 protruding to the outer surface of the cap plate 30. The connection tab 52 electrically connected to the second terminal 42 is coupled to and welded to the second protrusion 332 protruding to the inner surface of the cap plate 30. As a result, the second terminal 42 and the connecting tab 52 are electrically connected directly to the cap plate 30.

The first and

second protrusions

331 and 332 may be formed on the cap plate 30 through a coining process. As a result, the cap plate 30 is connected to the positive electrode 12 integrally with the second terminal 42 to be bipolar.

As shown in FIGS. 2 and 7, the connecting

tabs

51, 52, which are connected to the negative and

positive poles

11, 12, have a top plane 511, 521 (xy plane) and a side plane 512 that are bent at right angles. 522) (yz plane).

The

upper planes

511, 521 are coupled and welded to the rivet terminal 411 and the second protrusion 332 to be electrically connected, and the side planes 512, 522 are formed of the

tabs

112, 122. 2, the third welding (W2, W3) is electrically connected.

By caulking or welding around the inner and

upper planes

511, 521 of the penetrating rivet terminal 411 and around the inner and

upper planes

511, 521 of the penetrating rivet terminal 411, the connecting tab (

Planes

511 and 521 of 51 and 52 are fixed inside the rivet terminal 411.

7 is a perspective view of a state in which the ultrasonic main welded plain tabs and the reinforcing plate are laser welded to the connecting tab. Referring to FIG. 7, the

connection tabs

51 and 52 are third welded to the reinforcing

plates

113 and 123 on one side (eg, the side planes 512 and 522). The third welding W3 connects the

connection tabs

51 and 52 to the ultrasonically welded

plain tabs

112 and 122 and the reinforcing

plates

113 and 123 by laser welding. As a result, the electrode assembly 10 is electrically connected to the first and

second electrodes

41 and 42.

FIG. 8 is a front view showing a first embodiment of the state in which the plain tabs and the reinforcing plate are ultrasonically welded in a state and after the main welding, they are laser welded to the connecting tab. Referring to FIG. 8, the

plain tabs

112 and 122 and the reinforcing

plates

113 and 123 of the second welding W2 (ultrasound main welding) may be formed of the first and second null welds KW1 and KW2. It includes.

For convenience, despite the shapes of the horn 71 and the anvil 72 of FIG. 6, the first knurled weld KW1 is shown side by side in two rows along the y-axis direction, and the second knurled weld KW2 includes It is shown in one line between the 1 knurls KW1.

The first knurled weld KW1 is ultrasonically welded in the yz plane outside of the

plain tabs

112 and 122 and the reinforcing

plates

113 and 123 by the

first knurled portions

711 and 721 of the first planar area. do. The second null weld KW2 is ultrasonically welded by the second

null portions

712 and 722 of the second planar area smaller than the first planar area inside the first null weld KW1.

The first null weld KW1 is ultrasonically welded to the first depths D11 and D21 of the first

null portions

711 and 721. Despite the deep depth as in the first depths D11 and D21, the reinforcing

plates

113 and 123 prevent the

plain tabs

112 and 122 from contacting the horn 71 and the anvil 72, thereby making the plain portion To prevent damage to the

tabs

112, 122.

The second null weld KW2 is ultrasonically welded to the second depths D12 and D22 of the second

null portions

712 and 722 that are shallower than the first depths D11 and D21. Since the first knurled weld KW1 welds the reinforcing

plates

113 and 123 and the

plain tabs

112 and 122 sufficiently, the second knurled weld KW2 is ultrasonically depressed at a low depth of the second depths D12 and D22. Can be welded.

In the second knurled weld KW2, the first knurled weld KW1 and the reinforcing

plates

113 and 123 are ultrasonically welded to the lower second depths D12 and D22 so that they are less damaged than in the first knurled weld KW1. . Therefore, the second board welding part KW2 may further secure uniformity of laser welding during the third welding W3.

As an example, the second null weld KW2 is formed in the entire width direction (y-axis direction) of the

plain tabs

112 and 122. In addition, the third welding W3 may be performed at the second null welding part KW2 in the entire width direction (y-axis direction). Accordingly, the second null weld KW2 may uniformly transmit current to the reinforcing

plates

113 and 123 and the

connection tabs

51 and 52 in the entire width direction of the

plain tabs

112 and 122.

As an example, the reinforcing

plates

113 and 123 are disposed on both sides of the welded

plain tabs

112 and 122 to be ultrasonically main welded. In this case, damage to the

non-coated tabs

112 and 122 by the

first knurled portions

711 and 721 and the

second knurled portions

712 and 722 of the horn 71 and the anvil 72 can be prevented from both sides. Although not shown, the reinforcing plate may be disposed on any one surface of the welded non-coated tabs and ultrasonically welded.

Referring back to FIGS. 1 to 3, the insulating member 70 electrically insulates the electrode assembly 10 from the cap plate 30 and draws out the

tabs

112 and 122 from each other, and the second and third welding ( In order to process W2 and W3,

first cutouts

751 and 761 and

second cutouts

752 and 762 are provided.

The

first cutouts

751 and 761 are formed in the xy plane and open to allow the

tabs

112 and 122 to be pulled out from the electrode assembly 10 in the direction toward the cap plate 30 (z-axis direction). do.

The

second cutouts

752 and 762 are formed in the yz plane and open to weld the

plain tabs

112 and 122 and the reinforcing

plates

113 and 123 to the

connection tabs

51 and 52. That is, the

second cutouts

752 and 762 open in the x-axis direction to allow insertion and withdrawal of the horn 71 and the anvil 72.

Hereinafter, another embodiment of the present invention will be described. For the sake of convenience, in comparison with the first embodiment, the same configuration will be omitted and different configurations will be described.

Fig. 9 is a front view showing a second embodiment of the state in which the plain tabs and the reinforcing plate are ultrasonically welded to the connecting tab and laser welded to the connecting tab after the main welding. Referring to FIG. 9, in the second welding W22, the second null weld KW22 is formed at the center portion of the width direction (y-axis direction) of the

plain tabs

112 and 122.

The first null welding part KW21 is ultrasonically welded in the yz plane outside of the

plain tabs

112 and 122 and the reinforcing

plates

113 and 123 by the first knurl part of the first planar area. The second null weld KW22 is ultrasonically welded by the second null portion of the second planar area smaller than the first planar area inside the first null weld KW21.

In the second null weld KW22, the first null weld KW21 and the

reinforcement plates

113 and 123 are ultrasonically welded to the second depth of the second null portion lower than the first depth, so that the first null weld KW21 and the first null weld KW21 Less damaged. Accordingly, the second board welding part KW22 may further secure uniformity of laser welding during the third welding W23.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to the scope of the invention.

Description of the sign

10: electrode assembly 11: first electrode (cathode)

12: second electrode (anode) 13: separator

20: case 21: opening

30: cap plate 31: electrolyte injection hole

32: vent hole 41, 42: first and second terminals

51, 52: connection tab 61: external insulation member

62: internal insulation member 63: gasket

70: insulation member 71: horn

72: anvil 111, 121: coating portion

112, 122: plain tabs 113, 123: reinforcing plate

311: sealing stopper 321: vent plate

322: notch 331: first protrusion

332: second projection 411: rivet terminal

412: terminal plate 511, 521: upper plane

512, 522: side plane 711, 721: first knurl portion

712, 722: second null 751, 761: first incision

752, 762: 2nd incision D11, D21: 1st depth

D12, D22: 2nd depth H1: terminal hole

KW1, KW21: first board weld KW2, KW22: second board weld

W1, W3: 1st, 3rd welding W2, W22: 2nd welding

Claims

A case accommodating the electrode assembly;

A cap plate coupled to the opening of the case;

An electrode terminal provided on the cap plate;

A reinforcing plate drawn out of the electrode assembly and second welded to the first welded tabs; And

A connecting tab connected to the electrode terminal on the other side by a third welding to the reinforcing plate on one side

Secondary battery comprising a.
The method of claim 1,

The first welding is

Ultrasonic welding tack welds a plurality of plain tabs,

The second welding

A secondary battery for main welding the reinforcing plate by ultrasonic welding to the tack welded plain tabs.
The method of claim 2,

The third welding is

A secondary battery for connecting the connecting tab to the main welded plain tabs and the reinforcing plate by laser welding.
The method of claim 2,

The second welded plain tabs and the reinforcing plate

A first knurled weld welded to the outside from the horn and anvil to a first knurled portion of the first planar area, and

And a second null weld formed by ultrasonic welding to a second null portion having a second planar area smaller than the first planar area inside the first null weld.
The method of claim 4, wherein

The first null welded portion

Ultrasonically welded to the first depth of the first knurled portion,

The second null welding portion

The secondary battery is ultrasonically welded to a second depth of the second channel portion shallower than the first depth.
The method of claim 5,

The reinforcement plate is

A secondary battery disposed on one side or both sides of the non-welded tabs soluble welded.
The method of claim 5,

The second null welding portion

The secondary battery is formed over the entire width direction of the plain tabs.
The method of claim 5,

The second null welding portion

The secondary battery is formed in the center portion in the width direction of the plain tabs.
The method of claim 1,

An insulation member disposed between the electrode assembly and the cap plate and coupled to the cap plate;

The insulating member

A first incision opening the lead from the electrode assembly toward the cap plate of the plain tabs, and

And a second cutout that opens a process of welding the plain tabs and the reinforcing plate to the connection tabs.
The method of claim 1,

The electrode terminal

A first terminal installed in the cap plate in an insulating structure, and

A second terminal electrically connected to the cap plate;

The second terminal

Coupled to the first protrusion protruding to the outer surface of the cap plate is welded,

The connection tab electrically connected to the second terminal is

The secondary battery is coupled to the second protrusion protruding to the inner surface of the cap plate and welded.