RECHARGEABLE BATTERY

A rechargeable battery for preventing a safety device from being melted when a conductor penetrates is provided. The rechargeable battery includes an electrode assembly having a first electrode and a second electrode at both sides of a separator, a case housing the electrode assembly, a cap plate coupled to an opening of the case, a first electrode terminal and second electrode terminal that are installed in a terminal hole of the cap plate to be connected to the first electrode and the second electrode, respectively, and a safety device that is disposed between the electrode assembly and the case. The cap plate is electrically connected to one of the first electrode and the second electrode, and the safety device is electrically connected to the another of the first electrode and the second electrode. The safety device includes a plate portion and a protruded portion that protrudes from at least one surface of the plate portion.

DETAILED DESCRIPTION

The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. As those skilled in the art would realize, the described embodiments may be modified in various different ways, without departing from the spirit or scope of the present invention. The drawings and detailed description are to be regarded as illustrative in nature and not restrictive. In the context of the present application, when a first element is referred to as being “on” a second element, it can be directly on the second element or be indirectly on the second element, with one or more intervening elements interposed therebetween. Like reference numerals designate like elements throughout the specification.

FIG. 1shows a perspective view illustrating a rechargeable battery according to a first exemplary embodiment of the present invention, andFIG. 2shows a cross-sectional view illustrating the rechargeable battery taken along line II-II ofFIG. 1.

Referring toFIGS. 1 and 2, a rechargeable battery100according to the first exemplary embodiment includes an electrode assembly10that charges and discharges a current, a case15that houses the electrode assembly10, a cap plate20that is coupled to an opening of the case15, and a first electrode terminal21(hereinafter, referred to as a “negative terminal”) and a second electrode terminal22(hereinafter, referred to as a “positive terminal”) that are installed in the cap plate20.

For example, the electrode assembly10is formed by disposing a separator13, which is an insulator, between a first electrode11(hereinafter, referred to as a “negative electrode”) and a second electrode12(hereinafter, referred to as a “positive electrode”) and spiral-winding the negative electrode11, the separator13, and the positive electrode12in a jelly roll form.

In one embodiment, the negative electrode11and the positive electrode12include coated regions11aand12a, in which an active material is applied to a current collector of a metal plate, and uncoated regions11band12b, respectively, in which an active material is not applied to a current collector of the metal plate, which are thus formed as an exposed current collector.

In one embodiment, the uncoated region11bof the negative electrode11is formed at an end portion of one side of the negative electrode11, along the spiral-wound negative electrode11. The uncoated region12bof the positive electrode12is formed at an end portion of one side of the positive electrode12along the spiral-wound positive electrode12. Therefore, in one embodiment, the uncoated regions11band12bare each disposed at both ends of the electrode assembly10.

By way of example, in order to provide a space that houses the electrode assembly10and an electrolyte solution at the inside, the case15is formed in an approximately cuboid shape, and has an opening that connects an outside space to an inside space at a surface of the cuboid, through which the electrode assembly10is inserted into the case15.

In one embodiment, the cap plate20is installed in the opening of the case15, to close and seal the case15. By way of example, the case15and the cap plate20may be made of aluminum and may be welded together.

The cap plate20may further include an electrolyte injection opening29, a vent hole24, and terminal holes H1and H2. The electrolyte injection opening29may couple the cap plate20to the case15and enables injection of an electrolyte into the case15. After injection of the electrolyte, the electrolyte injection opening29may be sealed by a seal stopper27.

In order to discharge an internal pressure of the rechargeable battery100, the vent hole24may be closed and sealed by a vent plate25. When an internal pressure of the rechargeable battery100reaches a set pressure, the vent plate25may be cut out and the vent hole24opened. The vent plate25may have a notch25athat guides cutting out the vent plate25.

In one embodiment, the negative terminal21and the positive terminal22are installed in terminal holes H1and H2of the cap plate20and are electrically connected to the electrode assembly10. Specifically, in one embodiment the negative terminal21is electrically connected to the negative electrode11of the electrode assembly10, and the positive terminal22is electrically connected to the positive electrode12of the electrode assembly10. Therefore, the electrode assembly10can be drawn out to the outside of the case15through the negative terminal21and the positive terminal22.

In one embodiment, the negative and positive terminals21and22include rivet terminals21aand22athat are installed in each of the terminal holes H1and H2of the cap plate20, flanges21band22bthat are integrally widely formed in the rivet terminals21aand22awithin the cap plate20, and plate terminals21cand22cthat are disposed at the outside of the cap plate20to be connected to the rivet terminals21aand22a, respectively by riveting or welding.

In one embodiment, negative and positive gaskets36and37are installed between the rivet terminals21aand22aof the negative and positive terminals21and22and an inner surface of the terminal holes H1and H2of the cap plate20, to seal and electrically insulate the rivet terminals21aand22aof the negative and positive terminals21and22and the cap plate20, respectively.

In one embodiment, the negative and positive gaskets36and37are further extended between the flanges21band22band an inner surface of the cap plate20, to seal and electrically insulate the flanges21band22band the cap plate20, respectively. That is, the negative and positive gaskets36and37may be used to install the negative and positive terminals21and22in the cap plate20, thereby preventing or reducing leakage of an electrolyte solution through the terminal holes H1and H2.

In one embodiment, negative and positive lead tabs51and52electrically connect the negative and positive terminals21and22to the negative and positive electrodes11and12of the electrode assembly10, respectively. By coupling the negative and positive lead tabs51and52to a lower end of the rivet terminals21aand22aand by caulking the lower end, the negative and positive lead tabs51and52are connected to the lower end of the rivet terminals21aand22awhile being supported to the flanges21band22b, respectively.

In one embodiment, negative and positive insulation members61and62are installed between the negative and positive lead tabs51and52and the cap plate20, respectively, to electrically insulate the negative and positive lead tabs51and52and the cap plate20. Further, the negative and positive insulation members61and62are coupled to the cap plate20at one side and enclose the negative and positive lead tabs51and52, the rivet terminals21aand22a, and the flanges21band22bat another side, thereby stabilizing a connection structure thereof.

In one embodiment, the cap plate20is electrically connected to the negative terminal21or the positive terminal22. In the first exemplary embodiment, the cap plate20is electrically connected to the positive terminal22.

In one embodiment, an insulation member31at the negative terminal21is installed between the plate terminal21cand the cap plate20, to electrically insulate the plate terminal21cand the cap plate20. In this way, the cap plate20can maintain electrical insulation from the negative terminal21.

For example, the insulation member31may be interposed between the plate terminal21cand the cap plate20, and may penetrate the rivet terminal21a. Therefore, by coupling the insulation member31and the plate terminal21cto an upper end portion of the rivet terminal21aand caulking the upper end portion, the insulation member31and the plate terminal21care coupled to the upper end portion of the rivet terminal21a.

In one embodiment, the negative gasket36is further extended between the rivet terminal21aand the insulation member31. In this way, the negative gasket36further reinforces sealing and electric insulation between the rivet terminal21aand the insulation member31.

In one embodiment, a top plate32of the positive terminal22is formed with a conductive member and is installed between the plate terminal22cand the cap plate20, to electrically connect the plate terminal22cand the cap plate20. In this way, the cap plate20can maintain an electrical connection to the electrode assembly10through the positive terminal22.

For example, the top plate32is interposed between the plate terminal22cand the cap plate20and penetrates the rivet terminal22a. Therefore, by coupling the top plate32and the plate terminal22cto an upper end portion of the rivet terminal22aand caulking the upper end portion, the top plate32and the plate terminal22care coupled to the upper end portion of the rivet terminal22a.

In one embodiment, the positive gasket37is further extended between the rivet terminal22aand the top plate32. In this way, the positive gasket37prevents the rivet terminal22aand the top plate32from being directly electrically connected. That is, the rivet terminal22ais electrically connected to the top plate32through the plate terminal22cand indirectly electrically connected to the cap plate20through the top plate32.

FIG. 3shows an exploded perspective view illustrating an electrode assembly, a first insulation member, a safety device, and a second insulation member ofFIG. 2.

FIG. 4shows a cross-sectional view illustrating the electrode assembly, the first insulation member, the safety device, and the second insulation member taken along line IV-IV ofFIG. 2.FIG. 5shows a partial cross-sectional view illustrating a state in which a conductor is short-circuited in the safety device ofFIG. 4.

Referring toFIGS. 3 to 5, the rechargeable battery100of the first exemplary embodiment further includes a safety device71that is disposed between the electrode assembly10and the case15. In one embodiment, the safety device71is installed in an insulation structure between the electrode assembly10and the case15.

The safety device71is connected to an electrode of the electrode assembly10at the electrode terminal side in which the cap plate20is not connected. In the first exemplary embodiment, because the cap plate20is electrically connected to the positive terminal22, the safety device71is connected to the negative electrode11of the electrode assembly10at the negative terminal21side.

The safety device71is disposed on at least one side of the two sides of the electrode assembly10. In the first exemplary embodiment, the safety device71is disposed on both sides of the electrode assembly10. For example, the safety device71includes a plate portion711and a protruded portion712that protrudes from at least one surface of the plate portion711. In the first exemplary embodiment, the protruded portion712is formed at one surface of an outside of the plate portion711. That is, the safety device71has portions that are formed in different thicknesses.

In one embodiment, the plate portion711has a set thickness and thus can maintain self-resistance of the safety device71to a current flowing in a plane direction. Because the protruded portion712is protruded from the plate portion711, the protruded portion712increases penetration resistance to a current flowing in a thickness direction, while minimizing (or reducing) a decrease of self-resistance of the safety device71.

In this exemplary embodiment, the safety devices71are provided at each of both surfaces of the electrode assembly10. The safety device may be disposed at any one surface of the electrode assembly.

In this exemplary embodiment, a first insulation member81and a second insulation member82are disposed at both surfaces of the safety device71. In this way, the first insulation member81may electrically insulate the safety device71and the electrode assembly10and the second insulation member82may electrically insulate the safety device71and the case15.

In one embodiment, the plate portion711is in close contact with the first insulation member81, and the protruded portion712is in close contact with the second insulation member82. In this embodiment, the plate portion711has a planar form and supports the first insulation member81to the electrode assembly10in a stable structure. Further, the plate portion711has a separation space S from the second insulation member82according to a gap formed by the protruded portion712.

For example, the protruded portion712is provided to have plural portions, and the plural portions are separated from each other in a first direction (X-axis direction ofFIG. 3) on the safety device71, and extended in a second direction (z-axis direction) intersecting (crossing) the first direction (x-axis direction). Further, in one embodiment, the protruded portion712is formed in a quadrilateral-shaped cross-section structure, for example, a square-shaped or rectangular-shaped cross-section structure.

In embodiments where the safety device71is interposed between the electrode assembly10and the case15, before the electrode assembly10is short-circuited at the inside of the electrode assembly10by penetration of the conductor N, the safety device71is formed to cause a short circuit at the outside of the electrode assembly10. For this purpose, in an embodiment, the case15is electrically connected to the positive electrode12of the electrode assembly10, and the safety device71is electrically connected to the negative electrode11of the electrode assembly10.

For example, the safety device71is bent along the uncoated region11bof the negative electrode11of the electrode assembly10to be connected to the uncoated region11b. In this example, a negative lead tab may be directly connected to an uncoated region or may be connected to a safety device to be connected to an uncoated region through the safety device.

When a conductor N penetrates, the conductor N may penetrate the case15and penetrate the electrode assembly10. In this case, the safety device71that is disposed between the case15and the electrode assembly10causes a short circuit at the outside of the electrode assembly10before an internal short circuit of the electrode assembly10.

For example, a voltage that is charged at the electrode assembly10is quickly discharged at the outside of the electrode assembly10through the case15, the conductor N, and the safety device71. In this example, while the protruded portion712directly contacts the conductor N, the protruded portion712has high penetration resistance to a current flowing in a thickness direction. Therefore, the protruded portion712is not melted and maintains an external short circuit, thereby allowing enough discharge of a current that is charged at the electrode assembly10.

In order to further insulate the cap plate20and an upper portion of the safety device71, the second insulation member82may have a structure that closes an upper portion. Therefore, the second insulation member82may have drawn-out openings821and822that draw out the negative and positive lead tabs51and52in an upper part.

Hereinafter, further exemplary embodiments of the present invention are described. Elements identical to, similar to, or corresponding to, those of the first exemplary embodiment and other exemplary embodiments are omitted.

FIG. 6shows a cross-sectional view illustrating a rechargeable battery200according to a second exemplary embodiment of the present invention, andFIG. 7shows a partial cross-sectional view illustrating a state in which a conductor is short-circuited in the safety device ofFIG. 6. Referring toFIGS. 6 and 7, a plate portion721of a safety device72is in close contact with a second insulation member82, and a protruded portion722is in close contact with a first insulation member81.

The plate portion721has a planar form and supports the second insulation member82to a case15in a stable structure. Further, in an embodiment, the plate portion721has separation space S from the first insulation member81according to a gap formed by the protruded portion722.

When the conductor N penetrates, the plate portion721directly contacts a conductor N and has high penetration resistance to a current flowing in a thickness direction together with the protruded portion722of the opposite side. Therefore, the plate portion721is not melted and maintains an external short circuit, thereby allowing enough discharge of a current that is charged at the electrode assembly10.

FIG. 8shows a cross-sectional view illustrating a rechargeable battery300according to a third exemplary embodiment of the present invention.FIG. 9shows a partial cross-sectional view illustrating a state in which a conductor is short-circuited in the safety device ofFIG. 8. Referring toFIGS. 8 and 9, a safety device73includes a first protruded portion732on a first surface of the safety device and a second protruded portion733on a second surface of the safety device, opposite the first surface (i.e. having protruded portions at both surfaces of a plate portion731). In this exemplary embodiment, the first protruded portion732and the second protruded portion733are disposed in a symmetrical structure at both surfaces of the plate portion731.

The first protruded portion732is in close contact with a first insulation member81, and the second protruded portion733is in close contact with a second insulation member82. Further, the plate portion731has a separation space S from the first insulation member81according to a gap of the first protruded portion732and has separation space S from the second insulation member82according to a gap of the second protruded portion733.

According to one embodiment, the first protruded portion and the second protruded portion are disposed at alternate positions on the first and second surfaces of a plate portion. In these embodiments, a separation space between the first insulation member and the plate portion according to a gap of the first protruded portion, and separation space between the second insulation member and the plate portion according to a gap of the second protruded portion, are disposed at alternate positions.

When the conductor N penetrates, the second protruded portion733directly contacts the conductor N and has a high penetration resistance to a current flowing in a thickness direction together with the first protruded portion732and the plate portion731of the opposite side. Therefore, the plate portion731is not melted and maintains an external short circuit state, thereby enabling enough discharge of a current that is charged at an electrode assembly10.

FIG. 10shows a cross-sectional view illustrating a rechargeable battery400according to a fourth exemplary embodiment of the present invention.FIG. 11shows a partial cross-sectional view illustrating a state in which a conductor is short-circuited in the safety device ofFIG. 10. Referring toFIGS. 10 and 11, a safety device74includes a plate portion741and a protruded portion742that is protruded at one surface of the plate portion741.

For example, the protruded portion742has a streamline cross-section structure. In this example, the plate portion741is in close contact with a first insulation member81, and the protruded portion742is in close contact with a second insulation member82. The plate portion741has a planar form and supports the first insulation member81to an electrode assembly10in a stable structure.

The streamline cross-section structure of the protruded portion742reduces or removes separation space S between the plate portion741and the second insulation member82in spite of a gap of the protruded portion742, thereby securely forming an adhesion structure of the safety device74and the second insulation member82.

When the conductor N penetrates, the protruded portion742directly contacts the conductor N and has high penetration resistance to a current flowing in a thickness direction together with the plate portion741. Therefore, the plate portion741is not melted and maintains external short circuit state, thereby enabling enough discharge of a current that is charged at the electrode assembly10.

FIG. 12shows a cross-sectional view illustrating a rechargeable battery500according a fifth exemplary embodiment of the present invention. Referring toFIG. 12, a safety device75includes a plate portion751and a protruded portion752that is protruded at one surface of the plate portion751.

For example, the protruded portion752is extended in a first direction (X-axis direction ofFIG. 12) on the safety device75. In one embodiment, the protruded portion752forms a maximum thickness T1that is set in a third direction (y-axis direction) intersecting the first direction at the center of the first direction and forms a minimum thickness T2at both ends of the first direction.

The plate portion751is in close contact with the first insulation member81, and the protruded portion752is in close contact with a second insulation member82. The plate portion751has a planar form and supports the first insulation member81to the electrode assembly10in a stable structure.

A continuous streamline cross-section structure of the protruded portion752securely forms an adhesion structure of the safety device75and the second insulation member82. Because the safety device75of the fifth exemplary embodiment widely forms a range of the protruded portion752, compared to the first to fourth exemplary embodiments, the safety device75may have penetration of the conductor N over a wider range.

When the conductor N penetrates, the protruded portion752directly contacts the conductor N and has high penetration resistance to a current flowing in a thickness direction together with the plate portion751. Therefore, the plate portion751is not melted and maintains an external short circuit state, thereby enabling enough discharge of a current that is charged at an electrode assembly10.

FIG. 13shows an exploded perspective view illustrating an electrode assembly, a first insulation member, a safety device, and a second insulation member of a rechargeable battery600according to a sixth exemplary embodiment of the present invention. Referring toFIG. 13, a safety device76includes a plate portion761and a protruded portion762that is protruded at one surface of the plate portion761.

For example, the protruded portion762may include a plurality of first protruded lines763and a plurality of second protruded lines764intersecting one surface of the plate portion761. The first protruded lines763are separated from each other in a first direction (x-axis direction) on the safety device76, and extended in a second direction (z-axis direction) intersecting the first direction. The second protruded lines764are separated from each other in a second direction (z-axis direction) and extended in the first direction (x-axis direction) to intersect (cross) the first protruded line763.

The plate portion761is in close contact with the first insulation member81, and the protruded portion762is in close contact with a second insulation member82. The plate portion761has a planar form and supports the first insulation member81to the electrode assembly10in a stable structure.

Because the protruded portion762of the sixth exemplary embodiment is over a wider range, compared with the first to fourth exemplary embodiments, the protruded portion762corresponds to penetration of a conductor N over a wider range. Because the plate portion761of sixth exemplary embodiment is over a narrower range compared to the first to fourth exemplary embodiments, the protruded portion761corresponds to penetration of the conductor N over a narrower range.

When the conductor N penetrates, the first and second protruded lines763and764of the protruded portion762directly contact the conductor N and have high penetration resistance to a current flowing in a thickness direction together with the plate portion761. Therefore, the first and second protruded lines763and764of the protruded portion762are not melted and maintain an external short circuit state, thereby enabling enough discharge of a current that is charged at the electrode assembly10.