KR20180091301A - Rechargeable battery - Google Patents

Abstract

One embodiment of the present invention provides a rechargeable battery preventing flame and internal components from being blown out through a vent hole when a cell event occurs. According to one embodiment of the present invention, the rechargeable battery comprises: an electrode assembly charging and discharging current; a case housing the electrode assembly; a cap plate coupled to an opening of the case and having a vent hole in which a vent plate is installed; and an electrode terminal electrically connected to the electrode assembly and provided in a terminal hole provided in the cap plate. The cap plate includes a plurality of vents and a mesh unit integrally formed on an outer surface corresponding to the vent hole.

Description

[0002] RECHARGEABLE BATTERY [0003]

The present invention relates to a secondary battery having a vent plate in a cap plate for sealing an opening of a case.

A rechargeable battery is a battery which repeatedly performs charging and discharging unlike a primary battery. A small secondary battery is used in portable electronic equipment such as a mobile phone, a notebook computer, and a camcorder, and a large secondary battery can be used as a motor driving power source for hybrid vehicles and electric vehicles.

For example, the secondary battery includes an electrode assembly for charging and discharging, a case for accommodating the electrode assembly and the electrolyte, a cap plate coupled to the opening of the case, an insulating plate provided between the electrode assembly and the cap plate, And an electrode terminal electrically connected to the electrode assembly via an insulating plate.

The cap plate has a terminal hole for installing the electrode terminal, an electrolyte injection hole for injecting the electrolyte, and a vent hole for discharging the internal pressure. A vent plate is installed in the vent hole to close the vent hole. When the internal pressure reaches the set pressure, the vent plate is incised in the notch and opens the vent hole to reduce the internal pressure.

When a cell event occurs, the internal temperature of the secondary battery suddenly corresponds to the generated gas. Since the internal pressure of the secondary battery cuts the vent plate, a large amount of gas including the active material and the electrolytic solution is ejected to the outside via the insulating plate and the vent hole. As the temperature and pressure inside are lowered, explosion of the secondary battery is prevented.

However, when the conductive member penetrates, the insulating plate melts to form a flame due to the high temperature, and the flame and internal components are discharged to the outside of the cell through the vent hole And can not block the ejection.

An embodiment of the present invention provides a secondary battery that prevents a flame and internal components from being blown out through a vent hole when a cell event occurs.

A secondary battery according to an embodiment of the present invention includes an electrode assembly for charging and discharging a current, a case including the electrode assembly, a cap plate coupled to an opening of the case and having a vent hole in which a vent plate is installed, And an electrode terminal electrically connected to the electrode assembly and provided in a terminal hole provided in the cap plate, wherein the cap plate includes a plurality of vents and a mesh portion integrally formed on an outer surface corresponding to the vent hole do.

The secondary battery according to an embodiment of the present invention may further include an insulation plate disposed between the electrode assembly and the cap plate, wherein the insulation plate has an inner vent hole positioned between the vent hole and the mesh portion can do.

The cap plate may further include a protrusion protruding outward from the outer surface, and the mesh portion may be integrally formed with the protrusion.

The mesh portion may be formed in parallel with an outer surface of the cap plate.

The protrusion may be formed to have a thinner thickness as the protrusion is further away from the outer surface, and the mesh portion may be formed to have the same thickness as the end of the protrusion.

The vent hole may form a maximum opening area on the inner surface facing the electrode assembly and gradually decrease from the inner surface to the outer surface to form a minimum opening area on the outer surface.

The vent plate is welded to an inner surface forming a maximum opening area of the vent hole, and the mesh part may be integrally formed with a protrusion forming a minimum opening area.

The vent plate and the mesh portion may form a predetermined gap G between the vent plate and the mesh portion.

The vent plate may have a notch in the longitudinal direction of the cap plate at a widthwise center of the cap plate, and the gap may be set to be larger than a turning radius of the vent plate cut around the notch.

The vent plate may include a thin film portion that is formed as a thin film thinner than the thin film portion at the inner side of the thin film portion and is cut by the notch.

The gap may be set to be larger than a turning radius of the thin film portion which is pivoted inside the thick film portion.

As described above, according to one embodiment of the present invention, since the mesh portion is integrally formed on the cap plate at the outer surface corresponding to the vent hole, when the inner pressure is discharged through the vent hole at the time of the cell event, Can be prevented.

1 is a perspective view of a secondary battery according to an embodiment of the present invention.
2 is a cross-sectional view taken along the line II-II in FIG.
3 is a perspective view of the electrode assembly of FIG. 2. FIG.
FIG. 4 is a perspective view illustrating an electrode terminal of the electrode assembly shown in FIG. 3 connected to an electrode plate and an insulating plate and a gasket. FIG.
FIG. 5 is a cross-sectional perspective view of the vent plate and the cap plate cut away from the vent hole in FIGS. 1 and 3. FIG.
6 is a cross-sectional view illustrating the state before and after the operation of the vent plate in the vent hole portion of FIG. 5;

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

FIG. 1 is a perspective view of a secondary battery according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line II-II in FIG.

Referring to FIGS. 1 and 2, a secondary battery according to an embodiment includes an electrode assembly 101 and 102 for charging and discharging current, a case 30 housing the electrode assemblies 101 and 102, A cap plate 40 coupled to the opening 31 of the electrode assembly 101 to seal the opening 31 and electrode terminals 51 and 52 electrically connected to the electrode assemblies 101 and 102.

Further, the secondary battery of one embodiment further includes an insulating plate 20 installed between the electrode assemblies 101, 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.

FIG. 3 is a perspective view of the electrode assembly of FIG. 2, and FIG. 4 is a perspective view illustrating an electrode assembly of the electrode assembly of FIG. 3 and separating the insulating plate and the gasket.

3 and 4, the electrode assemblies 101 and 102 include a first electrode 11 (for example, a negative electrode) and a second electrode 12 (for example, a positive electrode) on both sides of a separator 13, , And is formed by winding or laminating (not shown) the cathode 11, the separator 13, and the anode 12.

Although the electrode assemblies 101 and 102 are formed in pairs in this embodiment, they may be formed in a larger number. The electrode assemblies 101 and 102 may be formed in a plate shape having both ends of elliptical shape (upper and lower ends in FIG. 3) so as to be accommodated in the case 30.

The positive and negative electrodes 11 and 12 are each formed of coating portions 111 and 121 coated with an active material on a collector of a metal foil (for example, Cu or Al foil) and an uncoated portion (Not shown).

The tabs 112 and 122 are spaced apart from each other at a distance D in one winding range T of one end of the wound or laminated electrode assembly 101 and 102 and the electrode assembly 101 and 102. That is, the tab 112 of the cathode 11 is disposed on one side of one end of the electrode assemblies 101 and 102, and the tab 122 of the anode 12 is disposed on the other side of the electrode assembly 101 ) Are spaced apart from each other.

Therefore, when the cathode 11 and the anode 12 are wound or laminated, the tab 112 of the cathode 11 is disposed on the left side at one end (upper end in Fig. 3) of the electrode assemblies 101 and 102, 12 are disposed on the right side at the same end (upper end in FIG. 3) of the electrode assemblies 101, 102.

For example, the tabs 112 and 122 of the negative and positive electrodes 11 and 12 are disposed on the cap plate 40 side and are superimposed on each other to be electrically connected to each other. The two electrode assemblies 101 and 102 are arranged side by side and electrically connected in parallel.

That is, in the two electrode assemblies 101 and 102, the tabs 112 of the two cathodes 11 are bent to face the tabs 112 of the different cathodes 11 and connected to the electrode terminals 51, The tabs 122 of the anode 12 are bent opposite to the tabs 122 of the different anodes 12 and connected to the electrode terminals 52.

Referring again to FIGS. 1 and 2, the case 30 houses the electrode assemblies 101 and 102 and the insulating plate 20 to form an outer appearance of the 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 shape and has a square opening 31 at one side thereof for inserting the electrode assemblies 101, 102.

2 and 4, the insulating plate 20 has tap holes 201 and 202 corresponding to the terminal holes H1 and H2. The tabs 112 and 122 of the electrode assemblies 101 and 102 received in the case 30 are connected to the electrode terminals 51 and 52 through the tab holes 201 and 202. [

That is, the insulating plate 20 electrically connects the electrode assemblies 101 and 102 and the cap plate 40, and enables the tabs 112 and 122 to be drawn out through the tap holes 201 and 202.

The cap plate 40 is coupled to the opening 31 of the case 30 to seal the case 30 and has two terminal holes H1 and H2. For example, the electrode terminals 51 and 52 are provided in the terminal holes H1 and H2 and the tapped holes 201 and 202, respectively. For example, the case 30 and the cap plate 40 may be formed of aluminum and welded to each other at the opening 31.

The electrode terminals 51 and 52 are connected to the tabs 112 and 122 of the electrode assemblies 101 and 102 to discharge current from the electrode assemblies 101 and 102 or to supply current to the electrode assemblies 101 and 102 So that it can be charged.

The electrode terminals 51 and 52 are provided to pass through the terminal holes H1 and H2 of the cap plate 40 and are connected to the tabs 112 and 122 passing through the tap holes 201 and 202 of the insulating plate 20 And is electrically connected. At this time, the tabs 112 and 122 are bent in parallel with the cap plate 40 and welded to the electrode terminals 51 and 52.

The electrode terminals 51 and 52 may have the same structure. The electrode terminals 51 and 52 include inner plates 511 and 521, pillars 512 and 522, and outer plates 513 and 523, respectively.

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 in a wide area and positioned between the cap plate 40 and the insulating plate 20. At this time, the tabs 112, 112, 122, 122 are bent on the two electrode assemblies 101, 102 facing each other and welded to the inner plates 511, 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 and protrude to the outside of the cap plate 40. [ The outer plates 513 and 523 are electrically connected to the pillars 512 and 522 at the outer surface of the cap plate 40. The pillars 512 and 522 are connected to the outer plates 513 and 523 by caulking or welding.

The electrode assemblies 101 and 102 can be drawn out of the case 30 through the tabs 112 and 122 and the electrode terminals 51 and 52. [ Further, since the tabs 112 and 122 are directly connected to the electrode terminals 51 and 52, the structure of drawing the electrode assemblies 101 and 102 out of the case 30 is simplified.

The gaskets 621 and 622 are interposed between the electrode terminals 51 and 52 and the cap plate 40 to electrically insulate and seal the electrode terminals 51 and 52 and the cap plate 40 with each other.

The gaskets 621 and 622 are provided between the columnar portions 512 and 522 of the electrode terminals 51 and 52 and the inner surfaces of the terminal holes H1 and H2 of the cap plate 40, The terminal holes H1 and H2 of the cap plate 40 are sealed and electrically insulated.

The columnar portions 512 and 522 are inserted into the terminal holes H1 and H2 via the gaskets 621 and 622 and the coupling holes of the outer plates 513 and 523 are inserted through the outer insulating members 631 and 632 514 and 524 and then caulking or welding the circumference of the coupling holes 514 and 524 to fix the pillars 512 and 522 to the outer plates 513 and 523. Thus, the electrode terminals 51 and 52 can be provided on the cap plate 40.

Referring again to FIGS. 1 and 2, the cap plate 40 further includes an electrolyte injection port 42 and a vent hole 41. The electrolyte injection port 42 allows the electrolyte solution to be injected into the case 30 after the cap plate 40 is joined and welded to the case 30. After the electrolyte solution is injected, the electrolyte injection hole 42 is sealed with a sealing plug 421.

The insulating plate (20) has an inner electrolyte inlet (28). The inner electrolyte injection port 28 allows the electrolyte injected through the electrolyte injection port 42 to be injected into the insulation plate 20 corresponding to the electrolyte injection port 42 provided in the cap plate 40.

The vent hole 41 is sealed by a vent plate 411 to discharge the internal pressure due to the gas generated in the secondary battery by the charging and discharging operations 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 is cut to open the vent hole 41 to discharge gas and internal pressure.

The insulating plate (20) has an inner vent hole (29) inside the vent hole (41). The inner vent hole 29 allows gas and internal pressure discharged to the vent hole 41 to be discharged to the outside of the insulating plate 20 in correspondence with the vent hole 41 provided in the cap plate 40 .

FIG. 5 is a cross-sectional perspective view of the vent plate and the cap plate cut away from the vent hole in FIGS. 1 and 3. FIG. Referring to FIGS. 1, 2 and 5, the cap plate 40 further includes a mesh portion 44 having a plurality of vent holes 43. The mesh portion 44 is integrally formed on the outer surface of the cap plate 40 corresponding to the vent hole 41. [

An internal vent hole 29 provided in the insulating plate 20 is positioned between the vent hole 41 and the mesh portion 44. The cap plate 40 includes projections 45 projecting outwardly from the outer surface. In this case, the mesh portion 44 may be integrally formed with the protruding portion 45. The mesh portion 44 is formed in parallel with the outer surface of the cap plate 40.

The protrusion 45 is formed to have a thinner thickness t1 as the cap plate 40 is further away from the outer surface. The mesh portion 44 is formed to have the same thickness t1 as the outermost end of the projecting portion 45. [

Accordingly, the vent hole 41 forms a maximum opening area on the inner surface facing the electrode assembly 10, and gradually decreases from the inner surface to the outer surface to form a minimum opening area on the outer surface. That is, the vent hole 41 is formed to have a structure that is reduced toward the outside by the inner surface of the projecting portion 45.

The vent plate 411 is welded to the inner surface forming the maximum opening area of the vent hole 41. The mesh portion 44 is integrally formed with the protruding portion 45 forming the minimum opening area of the vent hole 41.

For example, the mesh portion 44 and the air vents 43 are formed integrally with the cap plate 40 together with the projecting portion 45 by a coining process. Therefore, the process of forming the mesh portion 44 on the cap plate 40 can be simplified.

The minimum diameter D1 of the vent holes 43 is 1.2 times or more of the thickness t1 of the mesh portion 44 (D1? 1.2 * t1). In other words, the minimum diameter D1 of the air vents 43 allows discharge of gas and internal pressure while blocking the discharge of internal components in the cell. That is, when the minimum diameter D1 of the air vents 43 is less than 1.2 t, it is possible to limit the discharge of gas and internal pressure at the time of the cell event.

The vent plate 411 has a notch 412 to guide the incision. Gas and internal pressure generated inside the cell due to the cell event can be blown through the vent plate 411 through the notch 412 and discharged to the vent hole 41 and the mesh part 44.

In the event of a cell event, the mesh portion 44 having the air vents 43 can prevent the flame and internal components from being blown out while discharging the gas and the internal pressure passed through the vent hole 41 to the outside.

6 is a cross-sectional view illustrating the state before and after the operation of the vent plate in the vent hole portion of FIG. 5; Referring to FIG. 6, the vent plate 411 and the mesh portion 44 form a predetermined gap G between them.

The gap G allows the vent plate 411 to be cut open and pivotally opened when the vent plate 411 is cut out from the notch 412 and swung open to the outside (virtual line state).

5 and 6, in the vent plate 411, the notch 412 extends in the longitudinal direction (x-axis direction) of the cap plate 40 from the center in the width direction (y-axis direction) of the cap plate 40, As shown in FIG. The gap G is set to be larger than the turning radius R of the vent plate 411 cut around the notch 412.

The vent plate 411 is formed of a thin film thinner than the thick film portion 413 welded to the vent hole 41 and the thicker film portion 413 inside the thick film portion 413 and is cut by the notch 412 A thin film portion 414 may be included.

The thick film part 413 strengthens the weld strength of the vent plate 411 and the cap plate 40 in the vent hole 41 and the thin film part 414 facilitates the setting of the pressure at which the notch 412 is cut.

In this case, due to the gas and the internal pressure, the thick film portion 413 is not cut but only the thin film portion 414 is cut. Therefore, the gap G is set to be larger than the turning radius R of the thin film portion 414 which is pivoted inside the thick film portion 413. That is, the thick film portion 413 can reduce the gap G and the height of the protrusion 45 set between the vent plate 411 and the mesh portion 44.

Since the mesh part 44 having the ventilation holes 43 is integrally formed on the outer surface of the cap plate 40 corresponding to the vent hole 41 as described above, It is possible to prevent the flame and internal components from being blown out to the outside from the mesh portion 44. [

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, And it goes without saying that the invention belongs to the scope of the invention.

11: first electrode (cathode) 12: second electrode (anode)
13: separator 20: insulating plate
21: first protrusion 22: second protrusion
28: inner electrolyte inlet 29: inner vent hole
30: case 31: opening
40: cap plate 41: vent hole
42: electrolyte injection port 43: vent hole
44: mesh part 45:
51, 52: electrode terminal 101, 102: electrode assembly
111, 121: coating portion 112, 122: tab
201, 202: tap hole 411: vent plate
412: Notch 413:
414: thin film portion 421: sealing cap
511, 521: inner plate 512, 522:
513, 523: outer plate 621, 622: gasket
631, 632: outer insulating member D: distance
D1: Minimum diameter G: Spacing
R: turning radius T: winding range
t1: Thickness

Claims (11)

An electrode assembly for charging and discharging current;
A case housing the electrode assembly;
A cap plate coupled to an opening of the case and having a vent hole in which a vent plate is installed; And
And an electrode terminal electrically connected to the electrode assembly and provided in a terminal hole provided in the cap plate,
Lt; / RTI >
The cap plate
And a mesh portion integrally formed on an outer surface corresponding to the vent hole, the mesh portion including a plurality of vents. The method according to claim 1,
Further comprising an insulating plate disposed between the electrode assembly and the cap plate,
The insulating plate
And an inner vent hole positioned between the vent hole and the mesh portion. The method according to claim 1,
The cap plate
Further comprising a projection projecting outwardly from the outer surface,
The mesh portion
Wherein the protruding portion is integrally formed. The method of claim 3,
The mesh portion
And the cap plate is formed in parallel with an outer surface of the cap plate. The method of claim 3,
The protrusion
The thinner the thickness is, the farther away from the outer surface,
The mesh portion
Wherein the protrusion has a thickness equal to the thickness of the end of the protrusion. The method according to claim 1,
The vent hole
A maximum opening area is formed on the inner surface facing the electrode assembly,
And gradually decreases from the inner surface to the outer surface to form a minimum opening area at the outer surface. The method according to claim 6,
The vent plate
Welded to an inner surface forming a maximum opening area of the vent hole,
The mesh portion
And a protruding portion forming a minimum opening area. 8. The method of claim 7,
The vent plate and the mesh portion
And a gap (G) set between them is formed. 9. The method of claim 8,
The vent plate
And a notch in the longitudinal direction of the cap plate at a widthwise center of the cap plate,
The spacing
And a turning radius of the vent plate cut around the notch. 10. The method of claim 9,
The vent plate
A post-film portion welded to the vent hole, and
And a thin film portion formed on the inner side of the thick film portion to be thinner than the thick film portion and cut by the notch. 11. The method of claim 10,
The spacing
And a turning radius of the thin film portion pivoted inside the thick film portion is set larger than a turning radius of the thin film portion pivoted inside the thick film portion.

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