WO2018043890A1

WO2018043890A1 - Secondary battery

Info

Publication number: WO2018043890A1
Application number: PCT/KR2017/006563
Authority: WO
Inventors: 김종호; 김현석; 박시동; 이병익
Original assignee: 삼성에스디아이 주식회사
Priority date: 2016-09-02
Filing date: 2017-06-22
Publication date: 2018-03-08
Also published as: KR20180026223A; KR102260828B1

Abstract

A secondary battery according to an embodiment of the present invention comprises: an electrode assembly formed by disposing a first electrode and a second electrode on the sides of a separator; a case housing the electrode assembly; a cap plate coupled to an opening of the case and provided with a vent hole to which a vent plate is installed; an electrode terminal electrically connected to the electrode assembly and installed to a terminal hole provided in the cap plate; and an insulation plate disposed between the electrode assembly and the cap plate, wherein the insulation plate forms a vent region inside the vent hole, with holes having an area smaller than that of the vent hole.

Description

Secondary battery

The present disclosure relates to a secondary battery having an electrode assembly embedded in an inner space set by a case and a cap plate, and including an insulating plate between the electrode assembly and the 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 may be installed in an electrode assembly for charging and discharging, a case accommodating the electrode assembly and the electrolyte, a cap plate coupled to the opening of the case, an insulation plate provided between the electrode assembly and the cap plate, and a cap plate. And an electrode terminal electrically connected to the electrode assembly via the insulating plate.

The cap plate includes a terminal hole for installing electrode terminals, an electrolyte injection hole for electrolyte injection, and a vent hole for discharging internal pressure. Vent plates are provided in the vent holes to close the vent holes. When the internal pressure reaches the set pressure, the vent plate is cut out of the notch to open the vent hole to lower the internal pressure.

When the conductive member penetrates the secondary battery, a strong internal short circuit occurs within the secondary battery. Therefore, gas is generated while the internal temperature is correspondingly sharp. Since the internal pressure cuts the vent plate, a large amount of gas including the active material and the electrolyte is ejected to the outside via the insulating plate and the vent hole. As the temperature and pressure inside decrease, the explosion of the secondary battery is prevented.

Such a secondary battery considers discharge of internal pressure and gas during internal short-circuit, but when penetrating the conductive member, the insulation plate melts due to high temperature to block the vent hole, and thus, the safety of the battery is not considered to be deteriorated. .

In the secondary battery module including the cells of the secondary battery, as the vent hole is blocked in the first cell penetrated, heat is accumulated in the cell and transferred to the neighboring cell.

Neighboring cells that are exposed to high temperatures to the heat transferred can be secondarily chain ignited by internal pressure. That is, the heat accumulated in the first cell may lead to ignition of the entire module.

An aspect of the present invention is to provide a secondary battery that improves safety by preventing clogging of a vent hole by an insulating plate, despite a high temperature generated during an internal short circuit.

According to an embodiment of the present invention, a secondary battery includes an electrode assembly formed by disposing a first electrode and a second electrode on both sides of a separator, a case in which the electrode assembly is embedded, and a vent plate coupled to an opening of the case. A cap plate having a vent hole to be formed, an electrode terminal electrically connected to the electrode assembly and installed in a terminal hole provided in the cap plate, and an insulating plate disposed between the electrode assembly and the cap plate. The insulating plate forms a vent area with holes having an area smaller than that of the vent hole inside the vent hole.

The insulation plate may be formed of poly phenylene sulfide (PPS).

An area of the vent area may be larger than an area of the vent hole.

The vent region may form the holes in a lattice shape.

The insulating plate may include first protrusions protruding at a first height toward the cap plate from both sides of the cap plate in the longitudinal direction so as to be supported by the cap plate.

The insulating plate may include a second protrusion that protrudes to a second height lower than the first height in the vent region between the first protrusions to form the holes.

The second protrusion may be spaced apart from the cap plate at a predetermined interval.

According to an embodiment of the present invention, the vent area is formed by holes having an area smaller than that of the vent hole in the insulating plate disposed between the electrode assembly and the cap plate, so that the hot gas is vented despite the high temperature generated during the internal short circuit. Members (eg, torn separators) separated from the electrode assembly while discharging into the holes in the area can be held in the vent area that is inside the insulating plate.

In other words, while the vent area is kept open in the insulating plate, the members separated from the electrode assembly (eg, the torn separator) are held in the vent area, so that the vent hole in the cap plate can be kept open. have.

Therefore, the members (eg, the torn separator) separated from the electrode assembly may not be ejected to the outside through the vent hole, and propagation of the ignition to the neighboring cell during the internal short circuit may be prevented even in the module state. That is, even if the conductive member penetrates the secondary battery and generates a strong internal short circuit inside the secondary battery, safety of the secondary battery and the module can be ensured.

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.

4 is a perspective view of an electrode assembly applied to FIG. 2.

FIG. 5 is a perspective view illustrating the electrode terminal connected to the electrode assembly of FIG. 4 and the insulation plate and the gasket disassembled.

6 is a cross-sectional view showing a state before the internal short circuit of the vent hole and the vent area corresponding to each other.

7 is a cross-sectional view illustrating a state after an internal short circuit of the vent hole and the vent region corresponding to each other.

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, 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. 1.

1 to 3, a secondary battery according to an embodiment includes an

electrode assembly

101 and 102 for charging and discharging a current, a case 30 in which the

electrode assembly

101 and 102 are embedded, and a case 30. A cap plate 40 coupled to the opening 31 of the cap 31 to seal the opening 31, and

electrode terminals

51 and 52 electrically connected to the

electrode assemblies

101 and 102.

In addition, the secondary battery of one embodiment further includes an insulating plate 20 installed between the

electrode assemblies

101 and 102 and the cap plate 40. The insulating plate 20 electrically insulates the electrode assemblies 101 and 102 from the cap plate 40 and the

electrode terminals

51 and 52.

4 is a perspective view of an electrode assembly applied to FIG. 2, and FIG. 5 is an exploded perspective view illustrating an electrode terminal connected to the electrode assembly of FIG. 4 and an insulation plate and a gasket disassembled.

4 and 5, the

electrode assemblies

101 and 102 are formed on both sides of the separator 13, which is an electrical insulating material, and the first electrode 11 (eg, a cathode) and the second electrode 12 (eg, an anode). ), And formed by winding or laminating (not shown) the cathode 11, the separator 13, and the anode 12.

In the present embodiment, the electrode assemblies 101 and 102 are formed in pairs, but may be formed in a larger number. The electrode assemblies 101 and 102 may be formed in a plate shape with both elliptical ends (top and bottom of FIG. 4) to be accommodated in the case 30.

Well, the

positive electrodes

11 and 12 are coated

portions

111 and 121 coated with active materials on current collectors of metal foils (for example, Cu and Al foils), and non-coated portions of current collectors exposed without applying active materials. Forming

tabs

112, 122.

The

tabs

112, 122 are spaced apart from one another at one end of the wound or stacked

electrode assembly

101, 102 and at a single winding range T of the

electrode assembly

101, 102. That is, the tab 112 of the cathode 11 is disposed at one side of one end of the

electrode assembly

101, 102, and the tab 122 of the anode 12 is disposed at a distance D from the same end of the

electrode assembly

101, 102. Are spaced apart from each other.

Thus, when the negative electrode 11 and the positive electrode 12 are wound or stacked, the tab 112 of the negative electrode 11 is disposed on the left side at one end (top of FIG. 4) of the

electrode assembly

101, 102, and the positive electrode ( The tab 122 of 12 is disposed on the right side at the same stage (top of FIG. 4) of the

electrode assemblies

101, 102.

As an example, the

tabs

112 and 122 of the negative and

positive electrodes

11 and 12 are disposed on the cap plate 40 side and overlap each other to be electrically connected to each other. The two

electrode assemblies

101, 102 are arranged side by side and electrically connected in parallel.

That is, in the two

electrode assemblies

101 and 102, the tab 112 of one cathode 11 is bent to face the tab 112 of the other cathode 11 and connected to each other at the first electrode terminal 51. The tab 122 of the one positive electrode 12 is bent to face the tab 122 of the other positive electrode 12 and connected to the second electrode terminal 52.

Referring again to FIGS. 1 to 3, the case 30 may include

electrode assemblies

101 and 102 and an insulating plate 20 to form an appearance of a secondary battery and provide mechanical strength to the secondary battery.

The case 30 sets a space for accommodating the plate-shaped

electrode assemblies

101 and 102. 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 assemblies

101 and 102.

2, 3, and 5, the insulating plate 20 includes tab holes 201 and 202 corresponding to the terminal holes H1 and H2. Accordingly, the

tabs

112 and 122 of the

electrode assemblies

101 and 102 accommodated in the case 30 are connected to the first and

second electrode terminals

51 and 52 through the tab holes 201 and 202.

That is, the insulating plate 20 allows the

tabs

112 and 122 to be pulled out through the tab holes 201 and 202 while electrically insulating the

electrode assemblies

101 and 102 and the cap plate 40.

The cap plate 40 is coupled to the opening 31 of the case 30 to seal the case 30 and includes two terminal holes H1 and H2. For example, the first and

second electrode terminals

51 and 52 are provided in the terminal holes H1 and H2 and the tab holes 201 and 202. For example, the case 30 and the cap plate 40 may be made of aluminum and welded to each other at the opening 31.

In addition, the cap plate 40 further includes a vent hole 41 and an electrolyte injection hole 42. The vent hole 41 is closed by the vent plate 411 to discharge the internal pressure caused by the gas generated inside the secondary battery by the charging and discharging action of the

electrode assemblies

101 and 102.

For example, when the internal pressure of the secondary battery reaches the set pressure, the vent plate 411 may be cut to open the vent hole 41 to discharge the gas and the internal pressure. Vent plate 411 has a notch 412 leading to an incision.

The electrolyte injection hole 42 couples and welds the cap plate 40 to the case 30, and then injects the electrolyte into the case 30. After electrolyte injection, the electrolyte injection port 42 is sealed with a sealing stopper 421.

The insulating plate 20 has an internal electrolyte injection hole 28. The internal electrolyte injection hole 28 may correspond to the electrolyte injection hole 42 provided in the cap plate 40 so that the electrolyte injected through the electrolyte injection hole 42 may be injected into the insulating plate 20.

The first and

second electrode terminals

51 and 52 are connected to the

tabs

112 and 122 of the

electrode assemblies

101 and 102, respectively, to discharge current from the

electrode assemblies

101 and 102, or 102) to charge the current.

The first and

second electrode terminals

51 and 52 are installed through the terminal holes H1 and H2 of the cap plate 40 and the tabs passing through the tap holes 201 and 202 of the insulating plate 20. 112, 122 electrically. In this case, the

tabs

112 and 122 are bent in parallel with the cap plate 40 and welded to the first and

second electrode terminals

51 and 52.

The first and

second electrode terminals

51 and 52 may have the same structure. Referring to the drawings and described as an example, the first and

second electrode terminals

51 and 52 include

inner plates

511 and 521,

pillar portions

512 and 522, and

outer plates

513 and 523. .

The

inner plates

511 and 521 are formed to be wider than the areas of the

pillars

512 and 522 and are welded to the

tabs

112 and 122 with a large area, and are located between the cap plate 40 and the insulating plate 20. At this time, the

tabs

112, 112; 122, 122 in the two

electrode assemblies

101 and 102 are bent to face each other and welded to the

inner plates

511 and 521.

The

pillars

512 and 522 are connected to the

inner plates

511 and 521 and pass through the terminal holes H1 and H2 together with the

gaskets

621 and 622 to protrude out of the cap plate 40. The

outer plates

513 and 523 are electrically connected to the

column portions

512 and 522 at the outer surface of the cap plate 40. The

pillar portions

512, 522 are connected to the

outer plates

513, 523 by caulking or welding.

Accordingly, the

electrode assemblies

101 and 102 may be drawn out of the case 30 through the

tabs

112 and 122 and the first and

second electrode terminals

51 and 52. In addition, since the

tabs

112 and 122 are directly connected to the first and

second electrode terminals

51 and 52, the structure of drawing the

electrode assemblies

101 and 102 out of the case 30 is simplified.

Meanwhile, the

gaskets

621 and 622 are interposed between the first and

second electrode terminals

51 and 52 and the cap plate 40, so that the first and

second electrode terminals

51 and 52 and the cap plate 40 are interposed therebetween. Is electrically insulated and sealed.

The

gaskets

621 and 622 are disposed between the

pillar portions

512 and 522 of the first and

second electrode terminals

51 and 52 and the inner surfaces of the terminal holes H1 and H2 of the cap plate 40. Seals and electrically insulates between 512 and 522 and the terminal holes H1 and H2 of the cap plate 40.

The

column portions

512 and 522 are inserted into the terminal holes H1 and H2 through the

gaskets

621 and 622, and the coupling holes of the

outer plates

513 and 523 are provided through the external insulating

members

631 and 632. After inserting into the 514 and 524, the caulking or welding around the

coupling hole

514 and 524, the

pillar part

512 and 522 is fixed to the

outer plate

513 and 523. As a result, the first and

second electrode terminals

51 and 52 may be installed in the cap plate 40.

On the other hand, the insulating plate 20 includes a vent area VA having a plurality of holes H3 made of an area smaller than the area of the vent hole 41 inside the vent hole 41. Since the vent area VA corresponds to the vent hole 41 provided in the cap plate 40, the vent hole 41 receives an internal pressure that is increased by the hot gas generated in the

electrode assemblies

101 and 102 due to an internal short circuit. To be discharged.

The holes H3 in the vent area VA are members separated from the

electrode assemblies

101 and 102 while discharging the hot gas and the electrolyte even in the event of the high temperature generated during the internal short circuit of the secondary battery. The torn separator 13 can be held inside the insulating plate 20.

As such, the members separated from the electrode assemblies 101 and 102 (eg, the torn separator 13) while the vent area VA of the insulating plate 20 is kept open are vented area VA. Since the state held in the cap plate 40 can be maintained in the vent hole 41 in the open state.

That is, when the secondary battery is internally shorted, the members separated from the electrode assemblies 101 and 102 (eg, the torn separator 13) may not be ejected to the outside through the vent hole 41. Propagation of ignition into the cell can be prevented.

To this end, the insulating plate 20 may be formed of polyphenylene sulfide (PPS), which is a flame retardant material. That is, the insulation plate 20 may maintain the vent area VA while discharging the hot gas generated during internal short circuit to the holes H3.

In addition, the area of the vent area VA is formed larger than the area of the vent hole 41. That is, since the vent area VA is formed to have a larger area than the vent hole 41, the hot gas discharged into the vent hole 41 from the inside of the insulating plate 20 is not blocked in the vent area VA.

The holes H3 of the vent area VA are formed to have a smaller area than the vent holes 41, so that the separator 13 separated from the

electrode assemblies

101 and 102 blows toward the vent holes 41 during an internal short circuit. Can be prevented more effectively.

6 is a cross-sectional view showing a state before the internal short-circuit of the vent hole and the vent area corresponding to each other, and FIG. 7 is a cross-sectional view showing a state after the internal short-circuit of the vent hole and the vent area corresponding to each other.

3 and 5 to 7, as an example, the vent area VA may form the holes H3 in a lattice shape. The first and second protrusions protruding toward the cap plate 40 from both sides of the cap plate 40 in the longitudinal direction (x-axis direction) of the insulating plate 20 to be supported by the cap plate 40 ( 21) (see FIGS. 3 and 5).

The insulating plate 20 protrudes from the vent area VA between the first protrusions 21 to the second height H20 lower than the first height H10 to form the holes H3. ). Since the second protrusion 22 has a second height H20 that is higher than other portions on the insulating plate 20, strength of the second protrusion 22 may be improved in the vent area VA.

The second protrusion 22 is spaced apart from the cap plate 40 at a predetermined interval G1 at the vent hole 41 side. When an internal short circuit occurs in the secondary battery, the hot gas generated in the

electrode assemblies

101 and 102 passes through the vent holes 41 while cutting the vent plate 411 through the holes H3 of the vent area VA. Is discharged to the outside.

At this time, the separator 13 separated from the

electrode assemblies

101 and 102 is filtered through the vent area VA (see FIG. 7). In this process, if the pressure rises temporarily in the vent area VA, the vent area VA of the insulating plate 20 may be raised to immediately contact the cap plate 40 while removing the gap G1. have.

In this process, the insulating plate 20 having the second protrusion 22 may not be melted in the vent area VA and may maintain the holes H3 in an open state. Therefore, the hot gas including the electrolyte and the internal pressure may be discharged through the holes H3 of the vent area VA and the vent hole 41 of the cap plate 40.

Since the high temperature gas and the internal pressure generated in the secondary battery having the internal short circuit are discharged without accumulating, the clogging of the vent hole 41 in the first cell penetrated is prevented. Therefore, in the secondary battery module, chain ignition leading to neighboring cells may be blocked. That is, the safety of the secondary battery and the module to apply the same can be secured.

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

11: first electrode (anode) 12: second electrode (anode)

13: separator 20: insulation plate

21: first protrusion 22: second protrusion

30: case 31: opening

40: cap plate 41: vent hole

42: electrolyte injection ports 51, 52: first and second electrode terminals

101, 102: electrode assembly 111, 121: coating portion

112, 122: tap 201, 202: tap hole

411: vent plate 412: notch

421: sealing stopper 511, 521: inner plate

512, 522: pillar portion 513, 523: outer plate

514, 524: coupling holes 621, 622: gasket

631, 632: external insulation member D: distance

H1, H2: Terminal hole H3: Hole H10: First height

H20: Second height G1: Spacing

T: winding range VA: vent area

Claims

An electrode assembly formed by disposing the first electrode and the second electrode on both sides of the separator;

A case housing the electrode assembly;

A cap plate coupled to the opening of the case and having a vent hole in which a vent plate is installed;

An electrode terminal electrically connected to the electrode assembly and installed in a terminal hole provided in the cap plate; And

An insulating plate disposed between the electrode assembly and the cap plate;

The insulation plate is

And a vent area having holes smaller than an area of the vent hole inside the vent hole.
The method of claim 1,

The insulation plate is

A secondary battery formed of poly phenylene sulfide (PPS).
The method of claim 1,

The area of the vent area is

The secondary battery is formed larger than the area of the vent hole.
The method of claim 1,

The vent area is

A secondary battery for forming the holes in a grid shape.
The method of claim 1,

The insulation plate is

Secondary batteries including first protrusions protruding at a first height toward the cap plate on both sides in the longitudinal direction of the cap plate to be supported by the cap plate.
The method of claim 5,

The insulation plate is

And a second protrusion that protrudes from the vent region between the first protrusions to a second height lower than the first height to form the holes.
The method of claim 6,

The second protrusion is

The secondary battery is spaced apart from the cap plate at a predetermined interval.