Patent Description:
Demand for rechargeable batteries as an energy source is increasing according to demand for mobile devices and technological development. For example, a cylindrical rechargeable battery includes an electrode assembly for charging and discharging, a case accommodating the electrode assembly, and a cap assembly electrically connected to the electrode assembly to seal an opening side of the case. Such rechargeable batteries are disclosed in <CIT> and <CIT>.

For example, the electrode assembly is formed by disposing a positive electrode and a negative electrode on both surfaces of a separator, and winding the positive electrode, the separator, and the negative electrode in a jelly roll form. In the electrode assembly, one electrode is connected to the cap assembly through the current collecting plate, and the other electrode is connected to the case through a lead tab.

The cap assembly includes a current interrupt device (CID), and in this case, the opening of the case is closed and sealed by a beading portion and a crimping portion interposing a gasket between the current interrupt device and the case. In this case, as the gasket is compressed by the beading portion and the crimping portion, an inner end of the gasket may interfere with the current collecting plate, and in this case, the sealing force of the gasket with respect to the opening may be deteriorated.

In order to maintain the sealing force of the gasket, the current collecting plate may be connected to the beading portion of the case at one side of the gasket. In this case, an interference phenomenon in which one portion of the current collecting plate is connected to an electrode uncoated portion and the other portion of the current collecting plate presses the electrode uncoated portion may occur.

The present disclosure has been made in an effort to provide a rechargeable battery that may prevent interference between a current collecting plate and an electrode uncoated portion while securing sealing force of a case opening by a gasket.

An embodiment provides a rechargeable battery as defined in claim <NUM> as appended hereto, including: an electrode assembly formed by winding a first electrode, a separator, and a second electrode; a case accommodating the electrode assembly; an electrode terminal installed in an insulating state at a first opening on one side of the case; a first current collecting plate that connects the first electrode to the electrode terminal; a vent plate sealing a second opening on the other side of the case; a second current collecting plate connecting the second electrode to a beading portion of the case at an inner side of the vent plate; and a gasket interposed between the second collecting plate and the vent plate and between the second collecting plate and the case to perform a sealing action by a crimping portion connected to the beading portion, wherein the second current collecting plate includes a base portion disposed on an uncoated portion of the second electrode, a bottom welding portion extending in a radial direction from the base portion and welded to the uncoated portion of the second electrode, and a wing welding portion spaced apart from the bottom welding portion to be connected to the base portion by an elastic portion and welded to the beading portion.

A plurality of the bottom welding portions and a plurality of the wing welding portions may be respectively formed to be alternately disposed in a circumferential direction on the base portion.

A through-hole may be formed in a center of the base portion, and the bottom welding portion and the elastic portion may be connected by a concave groove at the base portion.

The bottom welding portion may form a first welding line along a radial direction, and the wing welding portion may form a second welding line along a circumferential direction.

The wing welding portion may extend in a circumferential direction to be longer than a width of the elastic portion.

The elastic portion includes a first elastic bending portion that is connected to the base portion to be upwardly bent and then is outwardly bent based on a radial direction, and a second elastic bending portion that is connected to the first elastic bending portion to be upwardly bent and then is outwardly inclined-bent based on a radial direction to be connected to the wing welding portion.

The gasket may be provided with an escape groove accommodating the wing welding portion.

The beading portion may be provided with a flat portion formed on an upper side of an inwardly convex curved portion, and the wing welding portion may be welded to the flat portion.

The escape groove may be formed at a right angle at a side of the wing welding portion, and may be formed at an obtuse angle corresponding to the second elastic bending portion at an inner side based on the radial direction.

A notch may be formed on an inner surface of the vent plate.

As described above, according to the embodiment of the present disclosure, since a gasket is sealed by a crimping portion interposed between a second current collecting plate and a case and connected to a beading portion, it is possible to secure sealing force of a case opening by the gasket and to prevent interference between the second current collecting plate and an electrode uncoated portion.

The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the scope of the present disclosure. The drawings and description are to be regarded as illustrative in nature and not restrictive. Like reference numerals designate like elements throughout the specification.

<FIG> illustrates a longitudinal cross-sectional view of a rechargeable battery according to an embodiment of the present disclosure. Referring to <FIG>, the rechargeable battery according to the embodiment includes an electrode assembly <NUM> that functions for charging and discharging, a case <NUM> accommodating the electrode assembly <NUM>, and a first current collecting plate <NUM>, a second current collecting plate <NUM>, and an electrode terminal <NUM> connected to the electrode assembly <NUM>, a vent plate <NUM>, and a gasket <NUM>.

The electrode assembly <NUM> is formed in a jelly roll state by winding a first electrode <NUM>, a separator <NUM>, and a second electrode <NUM>. The first electrode <NUM> and the second electrode <NUM> include coating portions 11a and 12a in areas in which active materials are applied on both surfaces of substrates respectively formed of thin metal plates, and non-coated portions 11b and 12b in areas in which the active materials are not applied and the substrates are exposed.

As an example, the first electrode <NUM> may form a positive electrode by coating a positive electrode active material on an aluminium (Al) substrate, and the second electrode <NUM> may form a negative electrode by coating a negative electrode active material on a copper (Cu) substrate. The uncoated portions 11b and 12b of the first and second electrodes <NUM> and <NUM> are provided at both ends of the electrode assembly <NUM> in a direction of a winding axis (both upper and lower ends in <FIG>), but are provided together with the electrode terminal <NUM> and the case <NUM> having different polarities in the same direction. The vent plate <NUM> is disposed at the opposite side of the electrode terminal <NUM>.

The case <NUM> is formed in a cylindrical shape to accommodate the electrode assembly <NUM>, and the electrode terminal <NUM> and the vent plate <NUM> are provided at both ends of the case <NUM> in the axial direction by the uncoated portions 11b and 12b, respectively. The electrode terminal <NUM> is connected to the first electrode <NUM> by the first current collecting plate <NUM>, and the case <NUM> is connected to the second electrode <NUM> by the second current collecting plate <NUM>. In this case, the vent plate <NUM> is electrically separated from the second collecting plate <NUM> and the case <NUM> and has no polarity.

The electrode terminal <NUM> connected to the first electrode <NUM> of the electrode assembly <NUM> inserted into the case <NUM> from the outside is installed at one side of the case <NUM>. To this end, the case <NUM> includes a first opening <NUM> partially opened on one side. The electrode terminal <NUM> is installed in an electrical insulation state from the case <NUM> while forming an airtight structure with respect to an electrolyte by interposing a sealing member <NUM> in the first opening <NUM>.

In this case, the first current collecting plate <NUM> is electrically connected to the uncoated portion 11b of the first electrode <NUM> to be electrically and mechanically connected to the electrode terminal <NUM>. The first current collecting plate <NUM> is electrically connected to the electrode terminal <NUM> in a structure that reduces resistance by contacting most of the uncoated portion 11b of the first electrode <NUM>.

As an example, the electrode terminal <NUM> may be connected to the first collecting plate <NUM> by welding at one end and installed in the first opening <NUM> of the case <NUM> in a rivet structure. The electrode terminal <NUM> may be formed to protrude from an outer surface of the case <NUM> around the first opening <NUM> to be used as a positive electrode terminal. In this case, the first current collecting plate <NUM> becomes a positive electrode current collecting plate.

In addition, the case <NUM> has a second opening <NUM> that is completely opened to insert the electrode assembly <NUM> into the other side. The vent plate <NUM> seals the second opening <NUM> after inserting the electrode assembly <NUM> into the case <NUM>, and is electrically separated from the case <NUM>.

In this case, the second current collecting plate <NUM> is electrically connected to the uncoated portion 12b of the second electrode <NUM> to be electrically connected to the case <NUM>. The second current collecting plate <NUM> is connected to case <NUM> in a structure that reduces resistance by contacting most of the uncoated portion 12b of the second electrode <NUM>.

The vent plate <NUM> is electrically separated from the second collecting plate <NUM>, and is installed in the second opening <NUM> of the case <NUM> through a crimping process. Due to the connection of the second collecting plate <NUM>, the case <NUM> may be used as a negative electrode terminal. In this case, the second current collecting plate <NUM> becomes a negative electrode current collecting plate.

<FIG> illustrates a cross-sectional view of a state before a vent plate is coupled by interposing a gasket into a second opening of a case of <FIG>. Referring to <FIG> and <FIG>, the second current collecting plate <NUM> connects the second electrode <NUM> to the beading portion <NUM> of the case <NUM>.

Through a beading process, a beading portion <NUM> is formed adjacent to the second opening <NUM> of the case <NUM>, and a crimping portion <NUM> connected to the beading portion <NUM> is formed through a crimping process. That is, the case <NUM> includes the beading portion <NUM> and the crimping portion <NUM>.

The beading portion <NUM> has a structure in which the electrode assembly <NUM> is recessed toward a center in a diameter direction of the case <NUM> from an upper side of the case <NUM> while the electrode assembly <NUM> is accommodated in the case <NUM>, thereby preventing the electrode assembly <NUM> from moving up and down.

The crimping portion <NUM> is connected to the beading portion <NUM> in a structure that relatively further protrudes from the beading portion <NUM> in the diameter direction. By the crimping process, the beading portion <NUM> is inclined downward while inwardly moving based on the diameter direction.

The gasket <NUM> is used in the crimping process. After the crimping process, the gasket <NUM> is interposed between the second collecting plate <NUM> and the vent plate <NUM> and between the second collecting plate <NUM> and the case <NUM> to perform sealing-function by the beading portion <NUM> and the clamping portion <NUM> connected thereto. In addition, the gasket <NUM> forms an airtight structure with respect to the electrolyte solution between the second collecting plate <NUM> and the second opening <NUM> of the case <NUM>.

<FIG> illustrates a perspective view of the second current collecting plate applied to <FIG>. <FIG> illustrates a cross-sectional view of the gasket applied to <FIG>. <FIG> illustrates a cross-sectional view of a state in which the vent plate is coupled to the second opening of the case with the gasket interposed in the state of <FIG>.

Referring to <FIG>, the second current collecting plate <NUM> includes a base portion <NUM>, a bottom welding portion <NUM>, an elastic portion <NUM>, and a welding wing portion <NUM>. The base portion <NUM> is placed on the uncoated portion 12b of the second electrode <NUM>.

The bottom welding portion <NUM> extends in a radial direction from the base portion <NUM> to be welded to the uncoated portion 12b of the second electrode <NUM>. The welding wing portion <NUM> is spaced apart from the bottom welding portion <NUM>, is connected to the base portion <NUM> by the elastic portion <NUM>, and is welded to the beading portion <NUM>.

The second current collecting plate <NUM> is formed by cutting and bending an original plate, and has a plurality of bottom welding portions <NUM> and wing welding portions <NUM>, respectively. The bottom welding portion <NUM> and the wing welding portion <NUM> are alternately disposed in the base portion <NUM> along a circumferential direction. Accordingly, the bottom welding portion <NUM> and the wing welding portion <NUM> may form a balanced structure along the circumferential direction.

During welding, the bottom welding portion <NUM> forms a first welding line <NUM> in the diameter direction. The wing welding portion <NUM> forms a second welding line <NUM> along the circumferential direction. The wing welding portion <NUM> extends in the circumferential direction to be longer than a width W of the elastic portion <NUM>.

Accordingly, the bottom welding portion <NUM> is evenly connected along the circumferential direction in the area of the uncoated portion 12b, and the wing welding portion <NUM> is evenly connected along the circumferential direction in the area of the beading portion <NUM>. In the second electrode <NUM>, a uniform current flow is possible along the circumferential direction in the entire area of the beading portion <NUM> of the case <NUM>.

The elastic portion <NUM> may repeatedly form bending in an axial direction (upward) and bending in an outer radial direction. As an example, the elastic portion <NUM> includes a first elastic bending portion <NUM> and a second elastic bending portion <NUM>.

The first elastic bending portion <NUM> is connected to the base portion <NUM> to be bent upwardly and then to be bent outwardly based on the radial direction. An upward height H1 of the first elastic bending portion <NUM> prevents the second elastic bending portion <NUM> from being separated from the uncoated portion 12b to interfere with the uncoated portion 12b.

The second elastic bending portion <NUM> is connected to the first elastic bending portion <NUM> to be bent upward and then is outwardly inclined-bent based on the radial direction to be connected to the wing welding portion <NUM>. A bent upward height H2 of the second elastic bending portion <NUM> and an inclined angle θ thereof outwardly inclined-bent based on the radial direction prevent interference with the beading portion <NUM>.

A length L from a bending start point to the upward bending point of the second elastic bending portion <NUM> in the radial outer direction of the first elastic bending portion <NUM> imparts elasticity to the elastic portion <NUM>, so that the upwardly bending point of the second elastic bending portion <NUM> has a force to move upward from the uncoated portion 12b. Accordingly, the length L of the elastic portion <NUM> further prevents the second elastic bending portion <NUM> from interfering with the uncoated portion 12b by separating it from the uncoated portion 12b.

In addition, the base portion <NUM> has a through-hole <NUM> in a center thereof, and the bottom welding portion <NUM> and the elastic portion <NUM> are connected to a concave groove <NUM> in the base portion <NUM>. The through-hole <NUM> and the concave groove <NUM> may absorb and alleviate deformation caused by welding the bottom welding portion <NUM> and the uncoated portion 12b and vibration and impact that may be transmitted between the wing welding portion <NUM> and the bottom welding portion <NUM>. The through-hole <NUM> and the concave groove <NUM> may have a size within a range capable of absorbing vibration and impact without increasing current resistance between the wing welding portion <NUM> and the bottom welding portion <NUM>.

The beading portion <NUM> includes a flat portion <NUM> formed parallel to a flat surface formed by a cross-section of the uncoated portion 12b at an upper side of an inwardly convex curved portion <NUM>. The wing welding portion <NUM> of the second current collecting plate <NUM> is welded to the flat portion <NUM>. Accordingly, the second collecting plate <NUM> is stably contacted and welded to the beading portion <NUM> of the case <NUM> to further realize a uniform flow of current.

In addition, since the wing welding portion <NUM> extends further along the circumferential direction from the end than the width W connected to the base portion <NUM>, the contact area and welding area with the flat portion <NUM> may be further increased to prevent an increase in resistance in the welding portion.

In this case, the gasket <NUM> has an escape groove <NUM> accommodating the wing welding portion <NUM>. The escape groove <NUM> increases stability of the gasket <NUM> by reducing deformation of the gasket <NUM> between the wing welding portion <NUM> and the vent plate <NUM> during the crimping process.

The gasket <NUM> further includes a compression portion <NUM> that comes into contact with the flat portion <NUM> at the outer side based on the radial direction of the escape groove <NUM> to act as a compression airtight seal. Despite the escape groove <NUM>, the compression portion <NUM> implements a sufficient airtight action between the flat portion <NUM> and the vent plate <NUM>.

The escape groove <NUM> is formed at a right angle at the compression portion <NUM> side to stably accommodate the end of the wing welding portion <NUM> to prevent misalignment between the wing welding portion <NUM> and the gasket <NUM>. The escape groove <NUM> may be formed at an obtuse angle at the inner side based on the radial direction to induce coupling of the bending structure of the wing welding portion <NUM>, the elastic portion <NUM>, and the second elastic bending portion <NUM> and to stably accommodate the bending structure of the wing welding portion <NUM>, the elastic portion <NUM>, and the second elastic bending portion <NUM>. The wing welding portion <NUM>, the elastic portion <NUM>, and the second elastic bending portion <NUM> may be bent to correspond to the obtuse structure of the escape groove <NUM>.

Referring to <FIG>, the gasket <NUM> has a through-hole <NUM> inside the escape groove <NUM> in the radius direction. The through-hole <NUM> connects an upper surface <NUM> and a lower surface <NUM> of the gasket <NUM> at right angles to the side thereof. The gasket <NUM> further includes a convex portion <NUM> convexly formed at the inside to further form the through-hole <NUM> inward in a through-direction. The convex portion <NUM> prevents the bending structure of the wing welding portion <NUM>, the elastic portion <NUM>, and the second elastic bending portion <NUM> from being pushed to the vent plate <NUM>.

Since the through-hole <NUM> of the gasket <NUM> is formed to correspond to an outer portion <NUM> of the vent plate <NUM>, the inner side of the gasket <NUM> compressed and deformed by the crimping process may be prevented from interfering with the second collecting plate <NUM>.

The vent plate <NUM> forms a notch <NUM> on the inner surface thereof. During a rechargeable battery event, the notch <NUM> is cut to discharge internal pressure, thereby preventing secondary explosion. The vent plate <NUM> is formed in a circular plate and includes a central portion <NUM>, a convex portion <NUM>, and the outer portion <NUM>.

The central portion <NUM> is formed to be concave toward the electrode assembly <NUM>, the convex portion <NUM> is formed to be convex so as to be away from the electrode assembly <NUM> at the outer side based on the diameter direction of the center portion <NUM>, and the outer portion <NUM> forms the same plane as the central portion <NUM> toward the electrode assembly <NUM> at the outer side based on the diameter direction of the convex portion <NUM>.

That is, an inner inclined surface <NUM> and an outer inclined surface <NUM> are formed at a portion where the central portion <NUM> and the convex portion <NUM> are connected and a portion where the convex portion <NUM> and the outer portion <NUM> are connected. The inner inclined surface <NUM> and the outer inclined surface <NUM> increase the rigidity of the vent plate <NUM> against the internal pressure of the rechargeable battery.

The notch <NUM> is formed on the inner surface of the convex portion <NUM> and the outer inclined surface <NUM> to receive intensive internal pressure during an event so that it may be easily cut. The notch <NUM> may be formed in the entire area along the circumferential direction of the vent plate <NUM>, or may be formed in a plurality spaced apart at predetermined intervals.

While this invention has been described in connection with what is presently considered to be practical embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims.

Claim 1:
A rechargeable battery comprising:
an electrode assembly (<NUM>) formed by winding a first electrode (<NUM>), a separator (<NUM>), and a second electrode (<NUM>);
a case (<NUM>) accommodating the electrode assembly (<NUM>);
an electrode terminal (<NUM>) installed in an insulating state at a first opening (<NUM>) on one side of the case (<NUM>);
a first current collecting plate (<NUM>) that connects the first electrode (<NUM>) to the electrode terminal (<NUM>);
a vent plate (<NUM>) sealing a second opening (<NUM>) on the other side of the case (<NUM>);
a second current collecting plate (<NUM>) connecting the second electrode (<NUM>) to a beading portion (<NUM>) of the case (<NUM>) at an inner side of the vent plate (<NUM>); and
a gasket (<NUM>) interposed between the second current collecting plate (<NUM>) and the vent plate (<NUM>) and between the second current collecting plate (<NUM>) and the case (<NUM>) to perform a sealing action by a crimping portion (<NUM>) connected to the beading portion (<NUM>),
wherein the second current collecting plate (<NUM>) comprises
a base portion (<NUM>) disposed on an uncoated portion (12b) of the second electrode (<NUM>),
a bottom welding portion (<NUM>) extending in a radial direction from the base portion (<NUM>) and welded to the uncoated portion (12b) of the second electrode (<NUM>), and
a wing welding portion (<NUM>) spaced apart from the bottom welding portion (<NUM>) to be connected to the base portion (<NUM>) by an elastic portion (<NUM>) and welded to the beading portion (<NUM>);
wherein
the elastic portion (<NUM>) comprises
a first elastic bending portion (<NUM>) that is connected to the base portion (<NUM>) to be upwardly bent and then is outwardly bent based on a radial direction, and
a second elastic bending portion (<NUM>) that is connected to the first elastic bending portion (<NUM>) to be upwardly bent and then is outwardly inclined-bent based on a radial direction to be connected to the wing welding portion (<NUM>).