Patent Description:
A rechargeable battery can be repeatedly charged and discharged, differing from a primary battery that is incapable of being recharged. The rechargeable battery is used in portable small electronic devices such as smartphones, laptops, and camcorders, or is used as a motor driving power source such as for hybrid vehicles.

The rechargeable battery includes an electrode assembly including a positive electrode, a negative electrode, and a separator positioned between the positive electrode and the negative electrode. The electrode assembly is received inside the case to perform charging and discharging, and an electrode terminal is provided to the case to supply or receive a current. The case may have a square shape or nay be a pouch type.

A vent unit may be provided to the case of the rechargeable battery. Regarding the vent unit, a vent plate is connected to a lower portion of the vent hole provided in the case. The vent plate is made thinner than the case, so when pressure inside the case increases because of overcharging, the vent plate is broken in advance to other portions to discharge a gas and secure safety of the rechargeable battery.

Recently, demands for capacity-increased rechargeable batteries such as medium to large rechargeable batteries are increasing, and concerns about the safety of the rechargeable batteries with increased integration are increasing.

However, the conventional rechargeable battery provides one vent unit for the cap plate, so it is difficult to quickly discharge the gas generated in the rechargeable battery.

<CIT>, forming the basis for the preamble of claim <NUM>, <CIT> and <CIT> disclose a rechargeable battery including a vent unit.

The present invention has been made in an effort to provide a rechargeable battery with a plurality of vent plates respectively closing and sealing a plurality of vent units to quickly discharge inner gas by being simultaneously separated from the respective vent units and opening the vent units when a pressure in a case reaches a set value.

An embodiment of the present invention provides a rechargeable battery as defined in claim <NUM>. In the above-configured rechargeable battery according to an embodiment of the present invention, when the elevating member moves up by the internal pressure caused by the gas generated in the case, a plurality of vent plates linking to the elevating member are simultaneously separated from the respective vent units to open the vent units, thereby quickly discharging the gas.

The elevating member may be installed in a center portion with respect to a length direction of the cap plate.

The vent units may be spaced from a through-hole of the cap plate in which the elevating member is penetrated and installed by a predetermined distance.

One pair of vent units from among the vent units may be spaced from the through-hole by a same distance.

Elevating A gasket for maintaining a sealed state of the rechargeable battery may be provided between the penetration unit and a through-hole of the cap plate.

The cap plate may include a moving guide unit positioned between the vent unit and the elevating member and guiding a moving path of the connection member.

The moving guide unit may include a rotor combined in a rotatable way to a rotation shaft installed while arranged in parallel to a width direction of the cap plate.

A settling groove formed to be concave so as to be indented toward the rotation shaft may be provided on an external circumferential surface of the rotor to allow the connection member to contact the rotor.

The vent unit may include: a first vent unit positioned on a lower portion of the cap plate and connected to an inside of the case; and a second vent unit positioned on an upper portion of the cap plate and including an inside connected to the first vent unit, and the vent plate may be installed in a portion in which the first vent unit is connected to the second vent unit to close and seal the vent unit.

A sealing portion is positioned along an exterior circumference of the vent plate on a connection portion of the first vent unit and the second vent unit to improve the sealing property of the vent unit.

The first vent unit may be connected to a bottom side of a second vent unit positioned in a direction becoming distant from the elevating member.

The second vent unit may include a guide groove provided long in a length direction of the cap plate on respective interior circumferences, the vent plate may include a guide protrusion positioned on respective sides facing the guide groove, and the guide protrusion may engage the guide groove and may slide along the guide groove.

The first vent unit may be connected to one side of a second vent unit positioned in a direction becoming distant from the elevating member.

The vent plate may be installed to be perpendicular to a cap plate, on a connection portion of the first vent unit and the second vent unit.

According to the embodiment of the present invention, when the pressure in the case reaches the set value, a plurality of vent plates linking to the elevating member moving up by the pressure in the case are simultaneously separated from the respective vent units, so the inner gas may be quickly discharged through the opened vent units.

According to the embodiment of the present invention, deterioration of the electrode assembly by the increase of the temperature in the rechargeable battery caused by the heat of the inner gas in the rechargeable battery may be prevented by quickly discharging the inner gas in the rechargeable battery.

The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown.

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

<NUM> shows a cross-sectional view of a rechargeable battery according to a first embodiment of the present invention.

Referring to FIG. <NUM>, the rechargeable battery includes an electrode assembly <NUM> for repeatedly performing a charging and discharging operation, a case <NUM> for receiving the electrode assembly <NUM> and an electrolyte solution, a cap plate <NUM> combined to an opening <NUM> of the case <NUM>, and electrode terminals installed on the cap plate <NUM>, that is, a negative terminal <NUM> and a positive terminal <NUM>.

For example, the electrode assembly <NUM> is formed by winding electrodes, that is, a negative electrode <NUM>, a separator <NUM>, and a positive electrode <NUM> that are stacked with the negative electrode <NUM> and the positive electrode <NUM>, in a jelly-roll state, on respective sides of the separator <NUM> that is an electrical insulator.

Further, the electrode assembly may be assembled by stacking the negative electrode and the positive electrode respectively made of a single plate with the separator therebetween, or by alternately stacking the negative electrode, the separator, and the positive electrode (not shown).

The negative electrode <NUM> and the positive electrode <NUM> include coated regions 11a and 12a made by applying an active material (not shown) to a current collector, and uncoated regions 11b and 12b made as exposed portions of the current collector to which no active material is applied on one side of each of the coated regions 11a and 12a. For example, the current collector of the negative electrode <NUM> may be formed of a copper thin film, and the current collector of the positive electrode <NUM> may be formed of an aluminum thin film.

The uncoated region 11b of the negative electrode <NUM> is positioned on one end of the negative electrode <NUM> along the coated region 11a of the wound negative electrode <NUM>. The uncoated region 12b of the positive electrode <NUM> is positioned on one end of the positive electrode <NUM> along the coated region 12a of the wound positive electrode <NUM>. That is, the uncoated regions 11b and 12b are disposed on respective ends of the electrode assembly <NUM> to allow electrical connection of the electrode assembly <NUM> and the negative terminal <NUM> and positive terminal <NUM>. The electrode assembly <NUM> generates gas during a charging and discharging process.

The case <NUM> may have a rectangular parallelepiped shape for forming an opening <NUM> on one side, allowing insertion of the electrode assembly <NUM> through the opening <NUM>, and providing a receiving space of the electrode assembly <NUM> and the electrolyte solution.

The cap plate <NUM> is combined with the opening <NUM> of the case <NUM> to close and seal the inside of the case <NUM> from the outside, thereby setting the closed and sealed receiving space together with the case <NUM>. For example, when the case <NUM> and the cap plate <NUM> are made of aluminum, they are combined to each other and are then welded, and they may be made of the same material and may have an excellent welding property.

<FIG> shows an enlarged cross-sectional view of an elevating member and a vent unit according to a first embodiment of the present invention.

Referring to FIG. <NUM> and <FIG>, the cap plate <NUM> may include an electrolyte injection opening <NUM>, a through-hole (H), and two vent units <NUM> and <NUM>'.

The electrolyte injection opening <NUM> allows injection of the electrolyte solution into the case <NUM> after a combination of the cap plate <NUM> and the case <NUM>. After the electrolyte solution is injected, the electrolyte injection opening <NUM> is sealed by a sealing cap <NUM>.

The through-hole (H) may be provided to penetrate the cap plate <NUM> so that the inside of the case <NUM> may be connected to the outside, and it may be positioned on a center portion with respect to a length direction of the cap plate <NUM>. An elevating member <NUM> may be installed in the through-hole (H).

The elevating member <NUM> may be inserted into the through-hole (H) and may be installed in the cap plate <NUM>, and when the internal pressure of the case <NUM> reaches a predetermined pressure value, the elevating member <NUM> may move up by the internal pressure of the case.

The elevating member <NUM> may include a first extension <NUM>, a second extension <NUM>, and a penetration unit <NUM>.

The penetration unit <NUM> has a column shape and penetrates the cap plate <NUM> so that an upper end may be exposed outside the case <NUM>, and a lower end may be positioned inside the case <NUM>.

In this instance, a gasket <NUM> is provided between the penetration unit <NUM> and the through-hole (H) of the cap plate <NUM> into which the penetration unit <NUM> is penetrated and inserted, thereby acquiring air tightness and maintaining the sealed state.

The first extension <NUM> and the second extension <NUM> may be respectively positioned on the upper end and the lower end of the penetration unit <NUM>.

The first extension <NUM> may be formed when the upper end of the penetration unit <NUM> exposed outside the case <NUM> horizontally extends in respective directions.

The first extension <NUM> may have a plate-shaped structure with a circular or polygonal cross-section and may be formed by a horizontal extension.

The first extension <NUM> may be pressurized on an upper side of the cap plate <NUM> while the pressure inside the case <NUM> has a value that is less than a predetermined pressure and the elevating member <NUM> maintains its stopped state.

The second extension <NUM> may be formed when the lower end of the penetration unit <NUM> positioned inside the case <NUM> horizontally extends in respective directions.

The second extension <NUM> may also have a plate-shaped structure with a circular or polygonal cross-section and may be formed by a horizontal extension in a like manner of the first extension <NUM>.

Particularly, an area of the cross-section of the second extension <NUM> may be greater than the size of the through-hole (H) of the cap plate <NUM>.

This is to allow the second extension <NUM> to be caught on a bottom side of the cap plate <NUM> provided near the edge of the through-hole (H), thereby preventing the elevating member <NUM> from leaving the cap plate <NUM> while the elevating member <NUM> moves up by the internal pressure.

The vent unit <NUM> may be positioned on the cap plate <NUM> and discharges the inner gas generated by charging and discharging in the case <NUM> to the outside, thereby preventing the rechargeable battery from being exploded. A plurality of vent units <NUM> are positioned on the cap plate <NUM>, and the respective vent units <NUM> are closed and sealed by the vent plate <NUM>.

The vent units <NUM> may be spaced from the through-hole (H) in which the elevating member <NUM> is installed by a predetermined distance, and particularly, one pair of vent units <NUM> and <NUM>' may be spaced from the through-hole (H) by the same distance.

Regarding the rechargeable battery according to a first embodiment of the present invention, the one pair of vent units <NUM> and <NUM>' have the same configuration, so one vent unit <NUM> will be described.

<FIG> shows an enlarged perspective view of a vent unit according to a first embodiment of the present invention.

Referring to <FIG>, the vent unit <NUM> may include a first vent unit <NUM> and a second vent unit <NUM>. The first vent unit <NUM> may be positioned at a lower portion of the cap plate <NUM> and may be connected to the inside of the case <NUM>, and the second vent unit <NUM> may be positioned at an upper portion of the cap plate <NUM> and may be connected, while exposed, to the first vent unit <NUM>. Regarding the above-noted configuration, a sum of a height h1 of the first vent unit <NUM> and a height h2 of the second vent unit <NUM> may be equal to the thickness (t) of the cap plate <NUM>.

A vent plate <NUM> is installed in a portion in which the first vent unit <NUM> is connected to the second vent unit <NUM> to shut a connection passage connected to the outside from the inside of the case <NUM> and thereby close and seal the inside of the case <NUM>.

That is, when the internal pressure of the rechargeable battery reaches a predetermined pressure value, the vent plate <NUM> linked to the elevating member <NUM> is drawn toward the through-hole (H) so it is separated from the vent unit <NUM>, and the gas inside the case <NUM> may pass through the first vent unit <NUM> and the second vent unit <NUM> and may be discharged to the outside.

The first vent unit <NUM> may have a passage structure positioned between the bottom side of the second vent unit <NUM> and the space inside the case <NUM> and connecting the inside of the case <NUM> and the second vent unit <NUM>.

The first vent unit <NUM> may be positioned to be connected to the bottom side of the second vent unit <NUM> position to be in a direction becoming distant from the elevating member <NUM>.

The horizontal cross-section of the first vent unit <NUM> may be less than the horizontal cross-section of the second vent unit <NUM>.

The second vent unit <NUM> is a concave space generated when the upper side of the cap plate <NUM> is indented, and it may have an internal configuration having a rectangular cross-section.

A guide groove <NUM> formed in a length direction of the cap plate <NUM> may be provided on interior circumferences of respective sides of the second vent unit <NUM>.

The vent plate <NUM> may be installed on a portion connected to the first vent unit <NUM> on the second vent unit <NUM> to close and seal the inside of the case <NUM> from the outside, and a sealing portion may be positioned along an exterior circumference of the vent plate <NUM> so as to improve the sealing property.

The vent plate <NUM> may have a hexahedral shape and may include guide protrusions <NUM> positioned on respective lateral sides facing the guide groove <NUM>.

The guide protrusion <NUM> may engage with the guide groove <NUM> and may slide along the guide groove <NUM>.

However, the above-noted sliding is possible when the vent plate <NUM> links to the elevating member through a connection member to be described and the vent plate <NUM> is separated from the vent unit <NUM>.

<FIG> shows a detailed cross-sectional view of an elevating member and a vent unit of a rechargeable battery according to a second embodiment of the present invention, and <FIG> shows an enlarged perspective view of a vent unit according to a second embodiment of the present invention.

Referring to <FIG>, a vent unit <NUM> may include a first vent unit <NUM> and a second vent unit <NUM>.

The first vent unit <NUM> may be formed at the lower portion of the cap plate <NUM> and may be connected to one lateral side of the second vent unit <NUM>. Particularly, the first vent unit <NUM> may be connected to one lateral side of the second vent unit <NUM> positioned in the direction becoming distant from the elevating member <NUM>.

The first vent unit <NUM> is a concave space generated when the lower bottom side of the cap plate <NUM> is indented, and it may have an internal configuration having a rectangular cross-section.

Particularly, the second vent unit <NUM> may be connected to the first vent unit <NUM> on one lateral side positioned in a direction becoming distant from the elevating member <NUM> from among four inner lateral sides.

As described, a vent plate <NUM> is installed on a portion in which the first vent unit <NUM> is connected to the second vent unit <NUM> to close and seal the inside of the case <NUM> from the outside.

The vent plate <NUM> may have a thin plate shape, and a sealing portion may be positioned along the exterior circumference of the vent plate <NUM> on the portion in which the first vent unit <NUM> is connected to the second vent unit <NUM>, thereby improving the sealing property.

The vent plate <NUM> may be connected to the elevating member through a connection member to be described, may be separated from the vent unit <NUM>, and may open the vent unit <NUM>.

The present invention exemplifies that the vent plate respectively installed in a plurality of vent units links to the elevating member through a connection member, is simultaneously separated from the vent unit, and opens the vent unit, so the connection member will now be described. The connection member will now be described with reference to a first embodiment of the present invention, but is not limited thereto.

<FIG> shows perspective view of a vent plate according to a first embodiment of the present invention, connected to an elevating member through a connection member, and <FIG> show schematic diagrams of a process for discharging inner gas through a vent unit of a rechargeable battery according to a first embodiment of the present invention.

Referring to <FIG>, <FIG>, and <FIG> to <FIG>, the connection member <NUM> is positioned between a plurality of vent units <NUM> and the through-hole (H) on the cap plate <NUM>.

The vent plate <NUM> is connected to the elevating member <NUM> through the connection member <NUM>, so it moves in link with the elevating member <NUM>.

The connection member <NUM> includes a first end combined to one side of the vent plate <NUM>, and a second end combined to a lower portion of the first extension <NUM> of the elevating member <NUM> to thus connect the vent plate <NUM> and the elevating member <NUM>. The connection member <NUM> has constant rigidity and has flexibility, and for example, it may be a wire or a cable.

A moving guide unit <NUM> may be provided between the vent unit <NUM> and the through-hole (H) on the cap plate <NUM>, so it may guide a moving path of the connection member <NUM>.

The moving guide unit <NUM> may include a rotor <NUM> combined in a rotatable way to a rotation shaft <NUM> installed while arranged in parallel to a width direction of the cap plate <NUM>.

A settling groove <NUM> may be positioned to be concave in the external circumferential surface of the rotor <NUM> so that it may be indented toward the rotation shaft <NUM>, so the connection member <NUM> may move while stably settled on the rotor <NUM>.

The connection member <NUM> may, while a first end thereof is combined to one side of the vent plate <NUM>, extend in the first direction to surround part of the external circumferential surface of the rotor <NUM>, and may continuously extend in the second direction so that a second end may be combined to the lower portion of the first extension <NUM>.

Therefore, the moving path of the connection member <NUM> may be changed to the second direction from the first direction by the rotor <NUM>.

To sum up, regarding the rechargeable battery according to an embodiment of the present invention, when the pressure inside the case reaches a predetermined pressure value by the gas generated during the charging and discharging process of the electrode assembly <NUM>, the elevating member <NUM> moves up by the pressure inside the case.

The elevating member <NUM> is connected to the vent plates <NUM> and <NUM> for closing and sealing the vent units <NUM> and <NUM> through the connection member <NUM>, so the vent plates <NUM> and <NUM> move in link to the movement of the elevating member <NUM>.

In this instance, a moving guide unit <NUM> is provided between the elevating member <NUM> and the vent units <NUM> and <NUM> to change the moving path of the connection member <NUM> that moves as the elevating member <NUM> moves up, so a force facing the elevating member <NUM> is applied to the vent plates <NUM> and <NUM> connected to the connection member <NUM>, and the vent units <NUM> and <NUM> are separated.

Particularly, the present invention includes a plurality of vent plates for respectively closing and sealing a plurality of vent units, the respective vent plates link to the elevating member, and a plurality of vent plates are simultaneously opened, so the inner gas of the rechargeable battery may be quickly discharged to the outside and safety may be secured.

Claim 1:
A rechargeable battery comprising:
an electrode assembly (<NUM>);
a case (<NUM>) for receiving the electrode assembly;
a cap plate (<NUM>) combined to an opening of the case to close and seal an inside of the case and including a plurality of vent units (<NUM>, <NUM>);
a plurality of vent plates (<NUM>, <NUM>) for closing and sealing the respective vent units, characterised by an elevating member (<NUM>) penetrated and installed in the cap plate and moving up by an internal pressure of the case;
wherein each of the plurality of the vent plates (<NUM>, <NUM>) is connected to the elevating member (<NUM>) through a connection member (<NUM>) and is linked to the elevating member (<NUM>),
wherein
the elevating member (<NUM>) includes:
a penetration unit (<NUM>) passing through the cap plate so that a first end is exposed outside the case and a second end is positioned inside the case;
a first extension (<NUM>) formed such that the first end of the penetration unit horizontally extends in respective directions; and
a second extension (<NUM>) formed such that the second end of the penetration unit horizontally extends in respective directions.