Rechargeable battery

A rechargeable battery includes a terminal, a connector, and an insulator. The terminal protrudes from a cap plate and electrically connected to an electrode. The connector is between the first terminal and the cap plate and includes a hole for the terminal. The insulator overlaps a first area of a top surface of the connector and a first area of a bottom surface of the connector, and does not overlap a second area of the top surface of the connector and a second area of the bottom surface of the connector.

CROSS-REFERENCE TO RELATED APPLICATION

Korean Patent Application No. 10-2015-0099933, filed on Jul. 14, 2015, and entitled, “Rechargeable Battery,” is incorporated by reference herein in its entirety.

BACKGROUND

One or more embodiments described herein relate to a rechargeable battery.

2. Description of the Related Art

A rechargeable battery can be repeatedly charged and discharged. Low-capacity rechargeable batteries are used in portable electronic devices such as mobile phones, notebook computers, and camcorders. High-capacity rechargeable batteries are used as power sources for hybrid vehicle motors. When an over-discharge or overcharge condition occurs in a rechargeable battery having a metal case, ignition may occur as a result of high current that is momentarily generated.

SUMMARY

In accordance with one or more embodiments, a rechargeable battery includes a case; an electrode assembly in the case and including a first electrode and a second electrode; and a cap assembly including: a cap plate covering an opening of the case; a first terminal protruding from the cap plate and electrically connected to the first electrode; a connector including a conductive material and a through-hole for the first terminal, the connector between the first terminal and the cap plate; and an insulator including a non-conductive material, the insulator overlapping a first area of a top surface of the connector and a first area of a bottom surface of the connector and not overlapping a second area of the top surface of the connector and a second area of the bottom surface of the connector.

The insulator may include a first insulating layer overlapping the first area of the top surface of the connector, and a second insulating layer overlapping the first area of the bottom surface of the connector. The first portion may have a thickness substantially equal to a thickness of the first insulating layer, and the second portion may have a thickness substantially equal to a thickness of the second insulating layer. The second areas of the top and bottom surface of the connector may not overlap one another. The second areas of the top and bottom surfaces of the connector may be located at respective ends of the connector.

The connector may include a first portion extending from the second area of the top surface of the connector, and a second portion extending from the second area of the bottom surface of the connector. The conductive material may include aluminum or an alloy of aluminum. The non-conductive material may include a non-conductive polymer.

In accordance with one or more other embodiments, a rechargeable battery includes a case; an electrode assembly in the case and including a first electrode and a second electrode; and a cap assembly including: a cap plate covering an opening of the case; a first terminal protruding from the cap plate and electrically connected to the first electrode, and a connector including a conductive material, a through-hole for the first terminal, a body between the first terminal and the cap plate, first portions respectively extending from top and bottom surfaces at a first edge of the body, and second portions respectively extending from the top and bottom surfaces at a second edge of the body.

The rechargeable battery may include a first insulating layer overlapping a top surface of one of the first portions and a second insulating layer overlapping a bottom surface of one of the second portions. Each of the first and second insulating layers may include a non-conductive polymer. An upper side of one or more of the first portions may have a smaller width than that of a lower side of the one or more of the first portions, and a lower side of one or more of the second portions may have a smaller width than that of an upper side of the one or more of the second portions. The conductive material may include aluminum or an alloy of aluminum.

In accordance with one or more other embodiments, an apparatus for a rechargeable battery includes a connector having a first surface, a second surface, and a terminal hole; a first insulation layer overlapping a first area of the first surface; and a second insulation layer overlapping a first area of the second surface, wherein the first insulation layer does not overlap a second area of the first surface and the second insulation layer does not overlap a second area of the second surface, and wherein the second areas of the first and second surfaces do not overlap. The first surface may be substantially flat and the second surface may be substantially flat.

The first insulation layer may overlap an edge of the first surface, the second insulation layer may overlap an edge of the second surface, and the edge of the first surface may oppose the edge of the second surface. The first surface may be uneven, and the second surface may be uneven. A top surface of the first insulation layer may be substantially even with a top surface of the second area of the first surface, and a top surface of the second insulation layer may be substantially even with a top surface of the second area of the second surface.

DETAILED DESCRIPTION

Herein, the terms “connector,” “connecting member,” and “connection member” are used interchangeably to refer to the features identified in this specification by reference characters58,158,258, and358.

FIG. 1illustrates an embodiment of a rechargeable battery101, andFIG. 2illustrates a cross-sectional view of the rechargeable battery101taken along line II-II inFIG. 1. Referring toFIGS. 1 and 2, the rechargeable battery101includes an electrode assembly10spirally wound with a separator13between a first electrode11and a second electrode12, a case27for receiving the electrode assembly10and including an open side, and a cap assembly30for covering the open side of the case27. The rechargeable battery101may be, for example, a square-type lithium ion secondary battery, a lithium polymer battery, a cylindrical battery, or another type of battery.

The first electrode11may be, for example, a positive electrode and the second electrode12may be a negative electrode. The positive electrode11and the negative electrode12include a coated region and uncoated regions11aand12a. The coated region may be formed, for example, by applying an active material to a current collector, that is formed with a metal foil in a thin plate shape. The uncoated regions11aand12adoes not include the active material. The positive uncoated region11ais formed at one end of the positive electrode11in a length direction of the positive electrode11. The negative uncoated region12ais formed at another end of the negative electrode12in a length direction of the negative electrode12. The positive electrode11and the negative electrode12are spirally wound, with separator13serving as an insulator therebetween.

In another embodiment, the electrode assembly10may be configured by stacking the positive electrode and the negative electrode with a plurality of sheets and a separator therebetween.

The case27may have a substantially cuboidal shape and an opening on one side. The case27may be made of a metal such as aluminum or stainless steel.

The cap assembly30includes a cap plate31, a first terminal21, a connecting member58, and an insulating member70. The cap plate31covers the opening of the case27and may be formed, for example, of a thin plate extending in one direction. A seal stopper38may be installed in an electrolyte injection opening32of the cap plate31, and a vent plate39having a notch39aadapted to fracture at a threshold pressure may be installed in a vent hole34.

The first terminal21and a second terminal22may protrude through and/or from an upper portion of the cap plate31. For example, the first terminal21may protrude outside the cap plate31and is electrically connected to the first electrode. The first terminal21is electrically connected to the positive electrode11with a first current collecting member41as a medium. The second terminal22is electrically connected to the negative electrode12with a second current collecting member42as a medium. In another embodiment, the first terminal21may be electrically connected to the negative electrode and the second terminal22may be electrically connected to the positive electrode.

The first terminal21may be a rectangular plate. The first terminal21is electrically connected to the positive electrode11, with a connecting terminal25bonded to the first current collecting member41as a medium. The connecting terminal25may have a pillar shape, and an upper portion of the connecting terminal25may be fixed to the first terminal21(e.g., through welding) while inserted into the first terminal21. The upper portion of the connecting terminal25may be fixed to the first current collecting member41(e.g., through welding), and the first current collecting member41is electrically connected to the connecting terminal25and the first electrode11.

A sealing gasket59is inserted into a hole through which a terminal passes between the first terminal21and the cap plate31. Lower insulating members43are installed below the cap plate31for supporting the first current collecting member41.

Referring toFIG. 2, in one embodiment, the cap assembly30may include the second terminal22electrically connected to the negative electrode. The second terminal22may be a rectangular plate. The second terminal22is electrically connected to the negative electrode12, with a connecting terminal26bonded to the second current collecting member42as a medium. The connecting terminal26extends from and/or passes through the cap plate31and the second terminal22, and has an upper portion fixed to the second terminal22.

The connecting terminal26may have a pillar shape. An upper portion of the connecting terminal26may be fixed to the second terminal22(e.g., through welding) while inserted into the second terminal22. The upper portion of the connecting terminal26may be fixed to the second current collecting member42(e.g., through welding), and the second current collecting member42is electrically connected to the connecting terminal26and the second electrode12.

A sealing gasket55is inserted into a hole through which a terminal passes between the second terminal22and the cap plate31. A lower insulating member45is installed below the cap plate31for insulating the second terminal22and the second current collecting member42on the cap plate31.

A short-circuit protrusion that protrudes toward a short-circuit hole37is formed on a lower portion of the second terminal22. The second terminal22extends in one direction to cover the short-circuit hole37. An upper insulating member54is installed between the second terminal22and the cap plate31for electrically insulating the second terminal22and the cap plate31.

The cap assembly30includes a short-circuit member56for short-circuiting the positive electrode11and the negative electrode12. The short-circuit member56is electrically connected to the cap plate31, and is transformed and connected to the second terminal22when an internal pressure of the rechargeable battery101increases.

The short-circuit hole37is formed in the cap plate31. The short-circuit member56is between the upper insulating member54and the cap plate31in the short-circuit hole37. The second terminal22covers the short-circuit hole37on an upper portion of the short-circuit hole37. The short-circuit member56includes a curve that may be bent, for example, as a convex arc in a downward direction. The short-circuit member56also includes an edge outside the curve and fixed to the cap plate31.

The connection member58includes a conductive material (e.g., aluminum, or alloys including aluminum) and includes a through-hole58athrough which the first terminal21passes. The connection member58is between the first terminal21and the cap plate31and electrically connects the first terminal21and the cap plate31. Accordingly, the cap plate31and the case27are charged as the positive electrode.

The insulating member70covers at least part of a top surface and a bottom surface of the connecting member58. However, the insulating member70may allow part of the top surface and the bottom surface of the connecting member58to be exposed.

For example, the insulating member70does not cover the whole top surface and bottom surface of the connecting member58. The insulating member70includes an insulating material, e.g., the insulating member70may be or include an insulating tape. In another embodiment, the insulating member70may be manufactured by coating an insulating material on the top and bottom surfaces of the connecting member58and curing the same. In another embodiment, the insulating member may include a non-conductive polymer, e.g., Teflon or another material that does not conduct electricity.

FIG. 3illustrates an embodiment of the connection member58.FIG. 4is a perspective view of the connection member58inFIG. 3from a lower direction.FIG. 5is a lateral view of the connection member58inFIG. 3.

Referring toFIGS. 3 to 5, the insulating member70includes, for example, a first insulating layer70aand a second insulating layer70b. The first insulating layer70acovers the part of the top surface of the connection member58. The second insulating layer70bcovers the part of the bottom surface of the connection member58.

A first exposed side U1, which does not include the first insulating layer70a, is on part of the top surface of the connecting member58. A second exposed side U2, which does not include the second insulating layer70b, is on part of the bottom surface of the connecting member58. The first exposed side U1and the second exposed side U2are in opposite directions with reference to the through-hole58aand are positions that do not correspond to one another, e.g., at positions that do not overlap.

In one embodiment, the first exposed side U1and the second exposed side U2may be located at different ends or edges of the connection member58. For example, the first exposed side U1may be at a right region on the top surface of the connecting member58, and the second exposed side U2may be at a left region on the bottom surface of the connecting member58.

When electricity is applied to the connection member58of the rechargeable battery101(referring for example, toFIG. 2), current flows into the first exposed surface U1and the second exposed surface U2. The surfaces U1and U2do not vertically overlap. Accordingly, compared to a connection member which does not have the first exposed surface U1and the second exposed surface U2, the current path is increased which, in turn, causes resistance to be increased. This increase in resistance may reduce high current applied to the first electrode11during an over-discharge or overcharge condition. The reduction in high current may prevent ignition from occurring in the rechargeable battery.

FIG. 6illustrates another embodiment of a connection member158in a cap plate of a rechargeable battery.FIG. 7is a perspective view of the connection member158inFIG. 6from a lower direction.FIG. 8is a lateral view of the connection member158inFIG. 6.

Referring toFIG. 6toFIG. 8, the connection member158includes a first extension portion58band a second extension portion58c. The first extension portion58bextends from the first exposed surface U1in the upper direction. The second extension portion58cextends from the second exposed surface U2in the lower direction. The thickness of the first extension portion58bmay be the same as the thickness of the first insulating layer70a. Also, the thickness of the second extension portion58cmay be the same as the thickness of the second insulating layer70b.

Accordingly, the top surface of the first extension portion58bis positioned on the same surface as the top surface of the first insulating layer70a, and the bottom surface of the second extension portion58cis positioned on the same surface as the bottom surface of the second insulating layer70b. Thus, the connection member58may be interposed between the first terminal21(referring toFIG. 2) and the cap plate31(referring toFIG. 2) without separation.

FIG. 9illustrates another embodiment of a connection member258in a cap plate of a rechargeable battery.FIG. 10is a lateral view of the connection member258inFIG. 9.

Referring toFIGS. 9 and 10, the connection member258includes a body portion258a, a third extension portion258b, and a fourth extension portion258c. The body portion258aincludes a through-hole258dpassing through the first terminal21(referring toFIG. 11) positioned between the first terminal21(referring toFIG. 2) and the cap plate31(referring toFIG. 2). The third extension portion258bextends from the top and bottom surfaces of the left edge of the body portion258a. The fourth extension portion258cextends from the top and bottom surfaces of the right edge of the body portion258a.

The cap assembly31(referring toFIG. 2) of this structure may include an insulating member170. The insulating member170may include a third insulating layer170aand a fourth insulating layer170b. The third insulating layer170amay include a non-conductive material formed in the top surface of the third extension portion258b. The fourth insulating layer170bis made of the non-conductive material and is formed in the bottom surface of the fourth extension portion158c.

The connection member258may be manufactured, for example, using less of the third insulating layer170aand the fourth insulating layer170bthan the connection member according to one or more of the previous embodiments. As a result, the connection member258may be less costly to manufacture. Also, the thickness of the body portion258aof the connection member258may be thinner than the connection member according to one or more of the previous embodiments. As a result, the connection member may be comparatively lighter in weight and less costly to manufacture.

FIG. 11illustrates another embodiment of a connection member358in a cap plate of a rechargeable battery.FIG. 12is a lateral view showing a state where a first terminal is positioned on the connection member358inFIG. 11.

Referring toFIGS. 11 and 12, in the connection member358, an upper side of a third extension portion358bhas a smaller right/left width than the lower side, and a lower side of a fourth extension portion358cmay have a smaller right/left width than the upper side. The cap assembly of this structure does not include the insulating member170(referring toFIG. 9) compared with the connection member258(referring to FIG.9). As a result, the manufacturing process may be simplified and manufacturing costs may be reduced.