WO2018143737A2

WO2018143737A2 - Secondary battery

Info

Publication number: WO2018143737A2
Application number: PCT/KR2018/001476
Authority: WO
Inventors: 이현수
Original assignee: 삼성에스디아이 주식회사
Priority date: 2017-02-06
Filing date: 2018-02-05
Publication date: 2018-08-09
Also published as: KR20180091302A; KR102397858B1; WO2018143737A3

Abstract

A secondary battery according to an embodiment of the present invention comprises: an electrode assembly formed by disposing a first and a second electrode, each having a coated part and uncoated part tabs, on both sides of a separator; a case for receiving the electrode assembly; a cap plate coupled to an opening of the case and electrically connected to the uncoated part tabs of the second electrode; a first electrode terminal installed in the cap plate while being electrically insulated therefrom, and connected to the uncoated part tabs of the first electrode; a second electrode terminal bonded to the cap plate with an insulating film interposed therebetween; and an overcharge safety device electrically connecting the cap plate and the second electrode terminal, and electrically disconnecting the cap plate and the second electrode terminal when the battery is overcharged.

Description

Secondary battery

The present disclosure relates to a secondary battery, and more particularly, to a secondary battery in which an electrode terminal connected to an overcharge safety device is installed in an insulating structure on a cap plate.

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 installed on the cap plate.

In addition, the secondary battery may include an overcharge safety device (OSD) between the electrode terminal and the cap plate so as to discharge gas and internal pressure generated therein by overcharging.

As an example, the overcharge safety device separates a positive electric charge member electrically connected directly to the negative electrode of the electrode assembly and a negative electric charge member electrically connected directly to the positive electrode from the outside of the cap plate. It is formed so as to short-circuit each of the negative and positive charging portions when overcharged.

In addition, the overcharge safety device is configured to electrically connect one of the electrode terminals installed on the cap plate directly to the negative electrode or the positive electrode of the electrode assembly, and to block the electrical connection between the electrode terminal and the electrode assembly during overcharging.

These overcharge safety devices include a structure for insulating the negative electrode charging portion and the positive electrode charging portion with the insulating member, or a structure for insulating the electrode terminal and the cap plate with the insulating member. Therefore, the overcharge safety device increases the number of parts and increases the material cost in the secondary battery.

One embodiment of the present invention is to provide a secondary battery that reduces the number of parts when the electrode terminal is installed in an insulating structure to the cap plate.

According to an exemplary embodiment of the present invention, a secondary battery includes an electrode assembly formed by disposing a first electrode and a second electrode having a coating part and a tab part on both sides of a separator, a case accommodating the electrode assembly, and a case of the case. A cap plate coupled to the opening and electrically connected to the uncoated tabs of the second electrode, a first electrode terminal installed in an electrically insulated state on the cap plate and connected to the uncoated tabs of the first electrode, the cap A second electrode terminal which is bonded to the plate via an insulating film, and the cap plate and the second electrode terminal are electrically connected to each other, and when overcharged, an overcharge which cuts off the electrical connection between the cap plate and the second electrode terminal. Include safety devices.

The second electrode terminal may include a terminal plate installed on the cap plate via the insulating film, and a sub terminal connecting the overcharge safety device and the terminal plate.

The terminal plate, the insulating film and the cap plate may be mechanically bonded.

The cap plate extends to form the first internal space toward the outside of the cap plate and protrudes toward the electrode assembly, and the terminal plate extends to fill the first internal space and to the outside of the cap plate. Two spaces are formed, and the insulating film may be disposed between the inner surface of the cap plate and the outer surface of the terminal plate in the first inner space.

The overcharge safety device may include a vent hole formed in the cap plate, and a vent plate installed in the vent hole to seal the vent hole and be connected to the sub terminal.

The secondary battery according to an embodiment of the present invention may further include a top insulator disposed between the electrode assembly and the cap plate.

The secondary battery according to an embodiment of the present invention further includes a first current collecting member disposed between the top insulator and the first electrode terminal, wherein the first current collecting member passes through a side surface of the top insulator. It may be connected to one side of the uncoated tabs of one electrode, and to the other side of the first electrode terminal.

The first electrode terminal is provided through a gasket in a terminal hole of the cap plate, and is provided through an internal insulating member on an inner surface of the cap plate, and the internal insulating member corresponds to a first internal portion corresponding to an electrolyte injection hole of the cap plate. An electrolyte injection hole may be provided, and the top insulator may include a second internal electrolyte injection hole corresponding to the first internal electrolyte injection hole.

The secondary battery according to an embodiment of the present invention further includes a second current collecting member disposed between the top insulator and the cap plate, and the second current collecting member passes through the side surface of the top insulator. It may be connected to one side of the tabs of the plain portion, the cap plate may be connected to the other side.

The second current collecting member disposed between the top insulator and the cap plate may include a first internal vent hole corresponding to the vent hole.

The top insulator may include a second internal vent hole corresponding to the first internal vent hole.

In one embodiment of the present invention, the second electrode terminal is bonded to the cap plate via an insulating film, and the cap plate and the second electrode terminal are connected to the overcharge safety device, so the second electrode terminal is installed in the cap plate with an insulating structure. When the number of parts can be reduced.

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. 2.

4 is a perspective view of an electrode assembly applied to FIG. 3.

5 is a perspective view of a state in which the electrode assembly and the current collecting member of FIG. 3 are disassembled.

FIG. 6 is a perspective view of the overcharge safety device and the electrode terminal (anode terminal) applied to FIG. 2 disassembled from the cap plate.

FIG. 7 is a cross-sectional view taken along line VIII-VIII of FIG.

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.

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, FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1, and FIG. 3 is a cross-sectional view taken along line III-III of FIG. 2.

1 to 3, a secondary battery according to an embodiment includes an electrode assembly 10 for charging and discharging current, a case 30 containing an electrode assembly 10 and an electrolyte, and an opening of the case 30. A cap plate 40 coupled to the 31 to seal the opening 31, a first electrode terminal 51 (for example, a negative electrode terminal) and a second electrode terminal 52, which are installed on the cap plate 40, as an example. , A positive terminal), and an overcharge safety device 60.

The secondary battery may further include a top insulator 20 formed of an electrical insulating material. The top insulator 20 is disposed between the electrode assembly 10 and the cap plate 40. Accordingly, the top insulator 20 electrically insulates the electrode assembly 10 and the cap plate 40.

In addition, the secondary battery further includes a first current collecting member 71 disposed between the top insulator 20 and the first electrode terminal 51, and the top insulator 20 and the cap on the second electrode terminal 52 side. It may further include a second collector member 72 disposed between the plate (40). Accordingly, the top insulator 20 further electrically insulates the first and second

current collecting members

71 and 72 from the electrode assembly 10.

The case 30 sets an internal space to accommodate the plate-shaped electrode assembly 10 and the electrolyte solution. For example, the case 30 is formed in a substantially rectangular parallelepiped, and has a rectangular opening 31 at one side thereof to insert the electrode assembly 10.

The cap plate 40 is coupled to the opening 31 of the case 30 to seal the case 30. As an example, the case 30 and the cap plate 40 may be made of aluminum and welded to each other at the opening 31. The cap plate 40 has a terminal hole H1 on which the first electrode terminal 51 is installed.

The cap plate 40 further includes an electrolyte injection hole 42. The electrolyte injection hole 42 couples the cap plate 40 to the case 30 to weld the electrolyte, and then injects the electrolyte into the cap plate 40 and the case 30. After the electrolyte injection, the electrolyte injection port 42 is sealed with a sealing stopper 420.

4 is a perspective view of an electrode assembly applied to FIG. 3. 2 to 4, the electrode assembly 10 includes a first electrode 11 (eg, a cathode) and a second electrode 12 (eg, an anode) on both sides of the separator 13, which is an electrical insulation material. And a cathode 11, a separator 13, and an anode 12 are wound or laminated (not shown). For convenience, the electrode assembly 10 of the wound structure will be described.

The

positive electrodes

11 and 12 are formed of

coatings

111 and 121 coated with active materials on current collectors of metal foils (for example, Cu and Al foils), and current collectors exposed by not applying active materials. And

non-stick tabs

112 and 122. The

plain tabs

112 and 122 are disposed at one end of the wound electrode assembly 10 and are disposed at a distance D within the single winding range T of the electrode assembly 10.

That is, the plain tabs 112 of the negative electrode 11 are disposed at one side (left side of FIG. 4) at one end (the top of FIG. 4) of the electrode assembly 10 to be wound, and the plain tabs of the positive electrode 12 ( 122 is disposed on the other side (right side of FIG. 4) at a distance D from the same end (top of FIG. 4) of the electrode assembly 10 to be wound.

As such, um, the

plain tabs

112 and 122 are provided at the

anodes

11 and 12 one by one for each winding of the electrode assembly 10 so as to flow a current to be charged and discharged. Resistance is reduced. Accordingly, the electrode assembly 10 may charge and discharge a high current through the

tabs

112 and 122.

The electrode assembly 10 may be formed as one (not shown) but is formed in two in the first embodiment. That is, the electrode assembly 10 includes a first assembly 101 and a second assembly 102 that are arranged side by side in the width direction (x-axis direction) of the cap plate 40.

In addition, the first and

second assemblies

101 and 102 may be formed in a plate shape that forms a semicircle at both ends in the y-axis direction so that the first and

second assemblies

101 and 102 may be accommodated in the inner space of the case 30 having a substantially rectangular parallelepiped shape.

5 is a perspective view of a state in which the electrode assembly and the current collecting member of FIG. 3 are disassembled. 3 to 5, the electrode assembly 10, that is, the first and

second assemblies

101 and 102 are arranged side by side in the x-axis direction and connected in parallel. The first and

second electrode terminals

51 and 52 are respectively installed on the cap plate 40 and electrically connected to the first and

second assemblies

101 and 102 through the

respective tabs

112 and 122. do.

The

non-coated tabs

112 and 122 connect the first and

second assemblies

101 and 102 to the first and

second electrode terminals

51 and 52 through the first and second current collecting

members

71 and 72. do. As an example, the

tabless tabs

112 and 122 may be formed in a plurality of groups.

The

non-coating tabs

112 and 122 include first tap groups G11 and G21 and second tap groups G12 and G22. The first tap group G11 and G21 are connected to the negative and

positive electrodes

11 and 12 of the first assembly 101, and the second tap group G12 and G22 are the negative and positive electrodes of the second assembly 102. Connected to (11, 12), respectively.

The first tab groups G11 and G21 are bent from one side in the second direction (x-axis direction) to the opposite side and welded to the first and second current collecting

members

71 and 72, respectively. The second tap groups G12 and G22 are bent toward the first tap groups G11 and G21 from opposite sides of the first tap groups G11 and G21 in the second direction (x-axis direction) so that the first and second current collecting members 71 are formed. , 72 respectively, by welding.

Referring to FIGS. 2 and 3 again, the first electrode terminal 51 is installed in the terminal hole H1 of the cap plate 40 in an electrically insulated state and is electrically connected to the uncoated tabs 112. For example, the first electrode terminal 51 includes a rivet portion 512, an inner plate 511, and an outer plate 513.

The first current collecting member 71 is connected to one side of the uncoated tabs 112 of the first electrode 11 via the side surface of the top insulator 20, and the uncoated tabs 112 of the first electrode terminal 51. ) Is connected to the other side.

The first electrode terminal 51 is electrically insulated from the cap plate 40 through an inner insulating member 611 and a gasket 621 between the inner surface of the cap plate 40. The inner insulating member 611 is in close contact with the cap plate 40 on one side and the inner plate 511 and the rivet part 512 of the first electrode terminal 51 on the other side.

The gasket 621 is provided between the rivet portion 512 of the first electrode terminal 51 and the inner surface of the terminal hole H1 of the cap plate 40, and thus the terminal hole of the rivet portion 512 and the cap plate 40. Seal and electrically insulate between (H1). In addition, the gasket 621 is further extended between the inner insulating member 611 and the inner surface of the cap plate 40 to further seal between the inner insulating member 611 and the cap plate 40.

The rivet portion 512 is inserted into the terminal hole H1 through the gasket 621 and the inner insulation member 611, and into the coupling hole 514 of the outer plate 513 through the outer insulation member 631. After the rivet portion 512 is inserted, the rivet portion 512 is fixed to the outer plate 513 by caulking or welding around the coupling hole 514. As a result, the first electrode terminal 51 may be installed in the cap plate 40 in an insulating and sealing structure.

The internal insulating member 611 includes a first internal electrolyte injection hole 421 corresponding to the electrolyte injection hole 42 of the cap plate 40, and the top insulator 20 corresponds to the first internal electrolyte injection hole 421. The second internal electrolyte injection port 422 is included. Therefore, the electrolyte injected into the electrolyte injection hole 42 may be stably injected into the electrode assembly 10 via the first and second internal electrolyte injection holes 421 and 422.

FIG. 6 is a perspective view of the overcharge safety device and the electrode terminal (anode terminal) applied to FIG. 2 disassembled from the cap plate, and FIG. 7 is a cross-sectional view taken along the line VIII-VIII of FIG.

2, 6, and 7, the second electrode terminal 52 and the anode terminal are bonded to the cap plate 40 through the insulating film 632. Therefore, the cap plate 40 may maintain an electrically insulated state from the second electrode terminal 52. The cap plate 40 is electrically connected to the uncoated tabs 122 of the second electrode 12 (anode). Accordingly, the cap plate 40 is charged with the second electrode 12 (anode).

The overcharge safety device 60 is configured to electrically connect the cap plate 40 and the second electrode terminal 52 and to block the electrical connection between the cap plate 40 and the second electrode terminal 52 during overcharging. do. Accordingly, the second electrode terminal 52 is electrically connected to the cap plate 40 through the overcharge safety device 60 to act as a positive electrode terminal.

For example, the overcharge safety device 60 is installed in the vent hole 41 formed in the cap plate 40 and the vent hole 41 to seal the vent hole 41 and to the second electrode terminal 52. The vent plate 43 is connected. The vent hole 41 and the vent plate 43 are provided above the second collector member 72 in the z-axis direction.

The vent plate 43 includes a thick film portion 431 welded to the vent hole 41, a thin film portion 432 provided inside the thick film portion 431 in the radial direction, and the thin film portion 432 and the thick film portion ( And a notch 433 formed to induce an incision between the 431. In addition, the vent plate 43 further includes a welding part 434 provided inside the thin film part 432 in the radial direction and formed thicker than the thick film part 431.

The second electrode terminal 52 is a terminal plate 523 installed through the insulating film 632 of the cap plate 40, and a sub terminal 522 connecting the overcharge safety device 60 and the terminal plate 523. ). At this time, the weld 434 of the vent plate 43 is connected to the sub terminal 522.

The sub terminal 522 also has

notches

525, 526. When the vent plate 43 is cut away from the notch 433 to open the vent hole 41, the

notches

525 and 526 guide the bending of the subplate 522 to smoothly open the vent hole 41. do.

As an example, the terminal plate 523, the insulating film 632 and the cap plate 40 are mechanically bonded. Mechanical joining includes mechanical presses, mechanical clinching, sheet metal joining, or TOX joining, which are joined and joined by mechanical deformation of the component parts.

In the bonded state, the cap plate 40 extends in the z-axis direction to protrude inwardly toward the electrode assembly 10 while forming the first inner space S1 toward the outside, and the terminal plate 523 is z-axis. The second inner space S2 is formed toward the outside of the cap plate 40 while being extended in the direction to fill the first inner space S1.

The insulating film 632 is disposed between the inner surface of the cap plate 40 and the outer surface of the terminal plate 523 in the first inner space S1. By mechanical bonding, the terminal plate 523 is fixed to the outer surface of the cap plate 40 via the insulating film 632. Since the insulating film 632 has a high ductility, the electrical insulating structure may be maintained despite the mechanical bonding between the terminal plate 523 and the cap plate 40.

As such, the second electrode terminal 52 includes a terminal plate 523, a subplate 522, and an insulating film 632, and the terminal plate 523 and the cap plate 40 through the insulating film 632. ) Is formed by mechanical bonding. Therefore, the number of articles constituting the second electrode terminal 52 is greatly reduced, thereby reducing the material cost.

Meanwhile, the second current collecting member 72 is connected to one side of the tabs 122 of the uncoated portion of the second electrode 12 via the side surface of the top insulator 20, and to the other side of the cap plate 40. do. Accordingly, the cap plate 40 is charged with the second electrode 12, that is, the anode.

The second current collecting member 72 is disposed between the top insulator 20 and the cap plate 40, and includes a first internal vent hole 441 corresponding to the vent hole 41, and the top insulator 20 is provided. A second internal vent hole 442 corresponding to the first internal vent hole 441 is provided. Therefore, during overcharging, the gas and the internal pressure generated therein pass through the second and first internal vent holes 442 and 441, act on the vent plate 43 through the vent hole 41, and the vent plate 43. ) Can be stably discharged through the vent hole 41.

When the internal pressure of the secondary battery reaches the set pressure due to overcharge or the like, the vent plate 43 of the overcharge safety device 60 is cut out of the notch 433. Therefore, the thin film part 432 and the weld part 434 provided in the notch 433 are separated from the thick film part 431. That is, the current path is blocked in the vent plate 43. As a result, the current is blocked in the second electrode terminal 52 connected to the welding unit 434 of the vent plate 43 by the sub terminal 522.

At this time, the

notches

525 and 526 induce bending of the sub terminal 522. Accordingly, the vent plate 43 may stably open the vent hole 41 without being disturbed by the sub terminal 522.

As such, when overcharged, the vent plate 43 is separated from the notch 433, and the sub plate 522 is bent from the

notches

525 and 526, so that the current may be stably blocked in the secondary battery.

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: top insulator 30: case

31: opening 40: cap plate

41: vent hole 42: electrolyte injection hole

43: vent plates 51 and 52: first and second electrode terminals

60: overcharge safety device 71, 72: first, second current collecting member

101, 102: first and second assembly 111, 121: coating

112, 122: tab tab 420: sealing stopper

421 and 422: First and second internal electrolyte injection holes 431: Thick film part

432:

thin film portion

433, 525, 526: notch

434: welds 441, 442: first and second internal vent holes

511: inner plate 512: rivet portion

513: outer plate 514: coupling hole

522: sub terminal 523: terminal plate

611: internal insulation member 621: gasket

631: external insulating member 632: insulating film

D: distance G11, G21: first tap group

G12, G22: 2nd tap group H1: terminal hole

S1, S2: 1st, 2nd internal space T: Once winding range

Claims

An electrode assembly formed by disposing a first electrode and a second electrode having a coating part and a tab part on both sides of the separator;

A case accommodating the electrode assembly;

A cap plate coupled to the opening of the case and electrically connected to the uncoated tabs of the second electrode;

A first electrode terminal installed in the cap plate in an electrically insulated state and connected to the uncoated tabs of the first electrode;

A second electrode terminal bonded to the cap plate via an insulating film; And

An overcharge safety device that electrically connects the cap plate and the second electrode terminal and blocks electrical connection between the cap plate and the second electrode terminal when overcharging;

Secondary battery comprising a.
The method of claim 1,

The second electrode terminal

A terminal plate installed on the cap plate via the insulating film; and

Secondary battery comprising a sub-terminal connecting the overcharge safety device and the terminal plate.
The method of claim 2,

The terminal plate, the insulation film and the cap plate

Secondary battery, mechanically bonded.
The method of claim 2,

The cap plate is

Extends to form a first inner space toward the outside of the cap plate and protrudes toward the electrode assembly,

The terminal plate is

Extends to fill the first internal space and forms a second space toward the outside of the cap plate;

The insulation film is

The secondary battery is disposed between the inner surface of the cap plate and the outer surface of the terminal plate in the first inner space.
The method of claim 3,

The overcharge safety device is

A vent hole formed in the cap plate, and

And a vent plate installed in the vent hole to seal the vent hole and to be connected to the sub terminal.
The method of claim 5,

And a top insulator disposed between the electrode assembly and the cap plate.
The method of claim 6,

Further comprising a first collector member disposed between the top insulator and the first electrode terminal,

The first current collecting member

It is connected to one side of the uncoated tabs of the first electrode via the side of the top insulator,

A secondary battery connected to the first electrode terminal to the other side.
The method of claim 7, wherein

The first electrode terminal

It is installed through the gasket in the terminal hole of the cap plate, the inner surface of the cap plate via an internal insulating member,

The internal insulation member is

A first internal electrolyte injection hole corresponding to the electrolyte injection hole of the cap plate;

The top insulator is

A secondary battery having a second internal electrolyte injection hole corresponding to the first internal electrolyte injection hole.
The method of claim 6,

Further comprising a second collector member disposed between the top insulator and the cap plate,

The second current collecting member

Is connected to one side of the uncoated tabs of the second electrode via the side of the top insulator

A secondary battery connected to the cap plate to the other side.
The method of claim 6,

The second collector member disposed between the top insulator and the cap plate is

A secondary battery having a first internal vent hole corresponding to the vent hole.
The method of claim 10,

The top insulator is

A secondary battery having a second internal vent hole corresponding to the first internal vent hole.