Patent Description:
A rechargeable battery is a type of battery which can be charged and discharged repeatedly, as opposed to a primary battery. Small-capacity rechargeable batteries may be used in small portable electronic devices such as mobile phones, laptop computers, and camcorders. Large-capacity rechargeable batteries may be used as power supplies for driving motors for hybrid vehicles and electric vehicles.

For example, a rechargeable battery includes an electrode assembly for performing charging and discharging operations, a case for accommodating the electrode assembly, a cap plate attached to an opening of the case, an electrode terminal for drawing the electrode assembly out of the cap plate, and a vent plate for releasing an internally generated, high-temperature gas and its pressure.

The cap plate has a terminal hole for attaching the electrode terminal and a vent hole for installing the vent plate. In addition, a current collecting member is used to connect the electrode terminal to the electrode assembly. The terminal hole, vent hole, and current collecting member cause an increase in the number of elements and make the configuration of the cap plate complicated, thereby increasing the cost of the rechargeable battery. Rechargeable batteries are disclosed in <CIT>, <CIT>, <CIT> and <CIT>.

The present invention has been made in an effort to provide a rechargeable battery that has a simple configuration by integrating elements configured on a cap plate.

The present invention provides a rechargeable battery according to the appended claims.

The first electrode terminal may include: a rivet portion installed with the gasket placed in the terminal hole; an external plate installed around the exposed end of the rivet portion and connected to the rivet portion; and an internal plate integrally connected to the underside of the rivet portion and connected to the uncoated region tabs of the first electrodes, with a current collecting member placed in between.

The electrode assembly may include a first assembly and a second assembly arranged side by side along the width of the cap plate, and the uncoated region tabs of the first electrodes may include an eleventh tap group connected to the first electrodes of the first assembly and a twelfth tab group connected to the first electrodes of the second assembly.

The eleventh tab group and the twelfth tab group may be bent and welded to the current collecting member.

The electrode assembly may include a first assembly and a second assembly arranged side by side along the width of the cap plate, and the uncoated region tabs of the first electrodes may include a twenty-first tap group connected to the second electrodes of the first assembly and a twenty-second tab group connected to the second electrodes of the second assembly.

The first tab group and the second tab group may be bent and welded to the current collecting member.

A surface of the cap plate corresponding to the vent hole may be sloped at a set angle with respect to a direction along the thickness of the cap plate.

According to an exemplary embodiment of the present invention, the rechargeable battery may have a simple configuration since the vent plate is formed integrally with the vent hole of the cap plate. In this case, since the vent plate is formed beyond the thickness of the cap plate, only the vent plate may be heat-treated, thereby eliminating the increased brittleness of the vent plate caused by the coining process.

Hereinafter, the present inventive concept will be described in detail with reference to the accompanying drawings so that those skilled in the technical field to which the present inventive concept pertains may easily carry out the present inventive concept.

The drawings and description are to be regarded as illustrative in nature and not restrictive. Like reference numerals designate like elements throughout the specification.

Throughout this specification and the claims that follow, when it is described that an element is "coupled" to another element, the element may be "directly coupled" to the other element or indirectly coupled to the other element through a third element. In addition, unless explicitly described to the contrary, the word "comprise" and variations such as "comprises" or "comprising", will be understood to imply the inclusion of stated elements but not the exclusion of any other elements.

<FIG> is a perspective view of a rechargeable battery according to an exemplary embodiment of the present invention. <FIG> is a cross-sectional view taken along the line II-II of <FIG>. Referring to <FIG> and <FIG>, a rechargeable battery according to an exemplary embodiment includes an electrode assembly <NUM> for performing current charging and discharging operations, a case <NUM> for accommodating the electrode assembly <NUM>, a cap plate <NUM> attached to an opening <NUM> of the case <NUM>, and first and second electrode terminals <NUM> and <NUM> electrically connected to the electrode assembly <NUM>.

The case <NUM> provides a space for accommodating a plate-shaped electrode assembly <NUM> and an electrolyte solution. For example, the case <NUM> is approximately cuboidal, and has a rectangular opening <NUM> at one side to insert the electrode assembly <NUM>.

The cap plate <NUM> is attached to the opening <NUM> of the case <NUM> to close and seal the case <NUM>. In an example, the case <NUM> and the cap plate <NUM> may be formed from aluminum and welded together at the opening <NUM>.

A top insulator <NUM> is disposed between the electrode assembly <NUM> and the cap plate <NUM>. The top insulator <NUM> is formed from an electric insulating material and electrically insulates the electrode assembly <NUM> and the cap plate <NUM>.

<FIG> is a perspective view of an electrode assembly applied to <FIG>. Referring to <FIG> and <FIG>, the electrode assembly <NUM> is formed by disposing a first electrode <NUM> (e.g., negative electrode) and a second electrode <NUM> (e.g., positive electrode) on either side of each separator <NUM>, which is an electrical insulating material, and spirally winding or stacking (not shown) the negative electrode <NUM>, separator <NUM>, and positive electrode <NUM>.

The positive and negative electrodes <NUM> and <NUM> include coated regions <NUM> and <NUM> here an active material is coated on a current collecting portion formed of a metal foil (e.g., copper or aluminum foil), and uncoated region tabs <NUM> and <NUM> where the active material is not coated thereon to expose the current collecting portion. The uncoated region tabs <NUM> and <NUM> are disposed at one end of the electrode assembly <NUM>.

That is, the uncoated region tabs <NUM> of the negative electrodes <NUM> are disposed on one side (the left side of <FIG>) of one end (the top of <FIG>) of the electrode assembly <NUM>, and the uncoated region tabs <NUM> of the positive electrodes <NUM> are spaced apart at the same end (the top of <FIG>) of the electrode assembly <NUM> and disposed at different positions (on the right side of <FIG>).

Moreover, the electrode assembly <NUM> is formed with a plurality of uncoated region tabs <NUM> and <NUM> to allow charge and discharge currents to flow, thereby reducing the overall resistance of the uncoated region tabs <NUM> and <NUM>. Accordingly, the electrode assembly <NUM> may charge and discharge a high electrical current through the uncoated region tabs <NUM> and <NUM>.

Although the electrode assembly <NUM> may be formed as a single unit, it may be formed as two units in the present exemplary embodiment. That is, the electrode assembly <NUM> includes a first assembly <NUM> and second assembly <NUM> arranged side by side along the width (x axis) of the cap plate <NUM> and connected in parallel. Moreover, the first and second assemblies <NUM> and <NUM> may be formed in the shape of a plate that forms a semicircle at both opposite ends along the y axis so that they are accommodated in an approximately cuboidal case <NUM>.

<FIG> is a cross-sectional view taken along the line IV-IV of <FIG>. Referring <FIG>, the first electrode terminal <NUM> is installed in a terminal hole H formed through the cap plate <NUM>, and electrically connected to the first and second assemblies <NUM> and <NUM> through the uncoated region tabs <NUM> of the first electrodes <NUM>.

The uncoated region tabs <NUM> may be formed in a plurality of groups. The uncoated region tabs <NUM> bypass the outer side of the top insulator <NUM> along the width (x axis) of the cap plate <NUM> and are connected to the first electrode terminal <NUM> along the width (x axis).

In an exemplary embodiment, the uncoated region tabs <NUM> of the first electrodes <NUM> include a first tab group G11 and a second tab group G12. The first tab group G11 is connected to the first electrodes <NUM> of the first assembly <NUM>, and the second tab group G12 is connected to the first electrodes <NUM> of the second assembly <NUM>.

The first electrode terminal <NUM> includes a rivet portion <NUM>, an internal plate <NUM>, and an external plate <NUM>. The first electrode terminal <NUM> is electrically insulated from the cap plate <NUM>, with a gasket <NUM> placed between it and the cap plate <NUM>.

The gasket <NUM> is installed between the rivet portion <NUM> of the first electrode terminal <NUM> and the inner surface of the terminal hole H of the cap plate <NUM>, and seals the gap between the rivet portion <NUM> and the terminal hole H of the cap plate <NUM> and electrically insulates them.

By inserting the rivet portion <NUM> into the terminal hole H, with the gasket <NUM> filling the gap in between, inserting it through a fastening hole <NUM> of the external plate <NUM>, with an external insulating member <NUM> placed between the external plate <NUM> and the cap plate <NUM>, and then caulking or welding the perimeter of the fastening hole <NUM>, the rivet portion <NUM> is fixed to the external plate <NUM>. As such, the first electrode terminal <NUM> may be installed to the cap plate <NUM>.

Thus, the rivet portion <NUM> is installed in the terminal hole H and protrudes outwards from the cap plate <NUM>. The rivet portion <NUM> is connected to the internal plate <NUM> inside the cap plate <NUM>, and connected to the external plate <NUM> outside the cap plate <NUM>. That is, the rivet portion <NUM> mechanically and electrically connects the internal plate <NUM> and the external plate <NUM> together.

The internal plate <NUM> is connected to a current collecting member <NUM> inside the cap plate <NUM>. The current collecting member <NUM> is connected to the uncoated region tabs <NUM>. That is, the uncoated region tabs <NUM> are welded to the current collecting member <NUM>, and the current collecting member <NUM> is welded to the internal plate <NUM>.

At this point, the uncoated region tabs <NUM> of the first electrodes <NUM> in the first and second assemblies <NUM> and <NUM> are divided into a first tab group G11 and a second tab group G12 to bypass the lateral side of the top insulator <NUM> at first and second sides, and are bent and welded to the current collecting member <NUM>. Accordingly, the first and second assemblies <NUM> and <NUM> may be drawn out of the case <NUM> through the uncoated region tabs <NUM> of the first electrodes <NUM>, the current collecting member <NUM>, and the first electrode terminal <NUM>.

<FIG> is a cross-sectional view taken along the line V-V of <FIG>. Referring to <FIG>, <FIG>, and <FIG>, the second electrode terminal <NUM> is formed integrally with the cap plate <NUM> and electrically connected to the first and second assemblies <NUM> and <NUM> through the uncoated region tabs <NUM> of the second electrodes <NUM>.

To this end, the cap plate <NUM> further includes a current collecting portion <NUM> formed integrally with it. The current collecting portion <NUM> protrudes toward the electrode assembly <NUM> so as to be connected to the uncoated region tabs <NUM> of the second electrodes <NUM>. In an example, the current collecting portion <NUM> may be formed on the cap plate <NUM> by a coining process.

The uncoated region tabs <NUM> may be formed in a plurality of groups. The uncoated region tabs <NUM> bypass the outer side of the top insulator <NUM> along the width (x axis) of the cap plate <NUM> and are connected to the second electrode terminal <NUM> through the current collecting portion <NUM> and the cap plate <NUM> along the width (x axis).

In an exemplary embodiment, the uncoated region tabs <NUM> of the second electrodes <NUM> include a first tab group G21 and a second tab group G22. The first tab group G21 is connected to the second electrodes <NUM> of the first assembly <NUM>, and the second tab group G22 is connected to the second electrodes <NUM> of the second assembly <NUM>.

The current collecting portion <NUM> is connected to the uncoated region tabs <NUM> of the second electrodes <NUM>. That is, the uncoated region tabs <NUM> are welded to the current collecting portion <NUM>, the current collecting portion <NUM> is formed integrally with the cap plate <NUM>, and the cap plate <NUM> is formed integrally with the second electrode terminal <NUM>.

At this point, the uncoated region tabs <NUM> of the second electrodes <NUM> in the first and second assemblies <NUM> and <NUM> are divided into a first tab group G21 and a second tab group G22 to bypass the lateral side of the top insulator <NUM> at first and second sides, and are bent and welded to the current collecting portion <NUM>. Accordingly, the first and second assemblies <NUM> and <NUM> may be drawn out of the case <NUM> through the uncoated region tabs <NUM> of the second electrodes <NUM>, the current collecting portion <NUM>, and the second electrode terminal <NUM>.

In an example, the second electrode terminal <NUM> may be formed on the cap plate <NUM> by a coining process. That is, the second electrode terminal <NUM> protrudes outwards from the cap plate <NUM> which is in the opposite direction to the direction the current collecting portion <NUM> protrudes.

The current collecting portion <NUM> and second electrode terminal <NUM> which are integrally formed by the coining process may need less elements and simplify the structure compared to the current collecting member <NUM> and first electrode terminal <NUM> connected to the first electrodes <NUM>.

Referring again to <FIG>, the cap plate <NUM> further includes an electrolyte injection opening <NUM> and a vent hole <NUM>. The electrolyte injection opening <NUM> allows for injection of an electrolyte solution into the case <NUM> after the cap plate <NUM> is attached and welded to the case <NUM>. After the injection of an electrolyte solution, the electrolyte injection opening <NUM> is sealed with a sealing closure <NUM>.

The top insulator <NUM> has an internal electrolyte injection opening <NUM>. Since the internal electrolyte injection opening <NUM> is formed corresponding to the electrolyte injection opening <NUM> formed in the cap plate <NUM>, it facilitates the injection of an electrolyte solution passing through the electrolyte injection opening <NUM> into the top insulator <NUM>.

The vent hole <NUM> is formed to release an internal pressure caused by a gas generated in the rechargeable battery by charging and discharging operations of the electrode assembly <NUM>, and is closed and sealed with a vent plate <NUM>.

In an example, the vent hole <NUM> and the vent plate <NUM> are formed integrally with the cap plate <NUM> by a coining process. The vent hole <NUM> and the vent plate <NUM> may need less elements and simplify the structure compared to a configuration in which the vent plate is manufactured separately and welded to the vent hole.

When the internal pressure of the rechargeable battery reaches a set pressure, the vent plate <NUM> is cut open to open the vent hole <NUM> and release a gas generated by overcharging and the internal pressure. To this end, the vent plate <NUM> has a notch <NUM> that guides the cutting of it.

The top insulator <NUM> has an internal vent hole <NUM>. Since the internal vent hole <NUM> is formed corresponding to the vent hole <NUM> formed in the cap plate <NUM>, it delivers an internal pressure lifting from a gas generated from the electrode assembly <NUM> to the vent hole <NUM> and facilitates the release of it.

<FIG> is a cross-sectional view of a vent plate formed integrally with a vent hole in a cap plate. Referring to <FIG> and <FIG>, the vent plate <NUM> is formed beyond the thickness T of the cap plate <NUM> by a coining process. That is, the vent plate <NUM> is protruded by a set height H1 from the inner surface of the cap plate <NUM> towards the electrode assembly <NUM> by being pulled down towards the electrode assembly <NUM>.

As the vent plate <NUM> is positioned beyond the thickness T of the cap plate <NUM>, unnecessary heat transfer around the vent plate <NUM> may be prevented when the vent plate <NUM> is heat-treated to eliminate the brittleness of the vent plate <NUM> caused by coining.

That is, unnecessary heat deformation of the cap plate <NUM> around the vent plate <NUM> and the vent hole <NUM> may be prevented. In an example, the heat treatment of the vent plate can be done by high-frequency heating, by which brittleness - that is, work hardening - may be eliminated.

Meanwhile, a high reduction rate in the coining process increases brittleness and lowers the durability of the vent plate <NUM>. Accordingly, the cap plate <NUM> is sloped at a set angle θ with respect to the thickness direction (z-axis direction) to enhance the durability of the vent plate <NUM> - that is, to lower the reduction rate. The angle θ used in the coining process makes it easy to expand the peripheral areas of the vent hole <NUM> and vent plate <NUM> on the cap plate <NUM>. In an example, the angle θ may be <NUM> degrees, plus or minus <NUM> degrees.

Claim 1:
A rechargeable battery comprising:
an electrode assembly (<NUM>) formed by disposing first and second electrodes (<NUM>, <NUM>) on either side of each separator (<NUM>), the first and second electrodes (<NUM>, <NUM>) each having coated regions (<NUM>, <NUM>) and uncoated region tabs (<NUM>, <NUM>);
a case (<NUM>) for accommodating the electrode assembly (<NUM>); and
a cap plate (<NUM>) attached to an opening (<NUM>) of the case (<NUM>) to close and seal the case (<NUM>) and having a vent plate (<NUM>) formed integrally with a vent hole (<NUM>), wherein the vent plate (<NUM>) is formed beyond the thickness of the cap plate (<NUM>);
wherein the vent plate (<NUM>) is formed by a coining process such that the vent plate (<NUM>) protrudes toward the electrode assembly (<NUM>) by a height (H1) from an inner surface of the cap plate (<NUM>),
wherein the rechargeable battery further comprises
a first electrode terminal (<NUM>) connected to the uncoated region tabs (<NUM>) of the first electrodes (<NUM>) and installed with a gasket (<NUM>) placed in a terminal hole (H) of the cap plate (<NUM>); and
a second electrode terminal (<NUM>) connected to the uncoated region tabs (<NUM>) of the second electrodes (<NUM>) and formed integrally with the cap plate (<NUM>),
wherein the second electrode terminal (<NUM>) protrudes outwards from the cap plate (<NUM>),
characterized in that
the cap plate (<NUM>) further comprises a current collecting portion (<NUM>) protruding toward the electrode assembly (<NUM>) so as to be connected to the uncoated region tabs (<NUM>) of the second electrodes (<NUM>).