Patent Description:
In general, a secondary battery is a battery which can be repeatedly used through a discharging process converting chemical energy into electrical energy and a reverse process, a charging process, and includes, as its kind, a nickel-cadmium (Ni-Cd) battery, a nickel-hydrogen (Ni-MH) battery, a lithium-metal battery, a lithium-ion (Li-ion) battery, a lithium-ion polymer battery, etc. Among these secondary batteries, the lithium secondary batteries, which have a high energy density and voltage, a long cycle life and a low self-discharge rate, have been commercialized and widely used.

Various kinds of gases, such as hydrogen, oxygen, nitrogen, carbon monoxide, carbon dioxide, hydrocarbons such as CnH2n-<NUM> (n=<NUM>~<NUM>), CnH2n (n=<NUM>~<NUM>) and CnH2n+<NUM> (n=<NUM>~<NUM>), other organic gas species, etc. may be generated depending on the reaction in the lithium secondary battery.

In addition, the lithium secondary battery is degraded as a large amount of gas is generated by the decomposition of an electrolyte according to repeated charging and discharging progresses, and this phenomenon appears differently depending on the design and use type of the battery. Therefore, analyzing the gas generated inside the battery to infer the degradation mechanism of the battery should essentially be performed in the development process of the battery.

Therefore, it is very important to collect and accurately analyze the gas generated in the secondary battery. Various gases are generated during operation of the lithium ion battery, and information on the composition and content of the generated gases is useful for the development of battery materials, optimization of battery manufacturing processes, and identification of causes of battery defects. To this end, it is important to develop a technology for collecting the gas generated inside the secondary battery.

Conventionally, in order to collect the gas generated in the secondary battery, the secondary battery was placed in a closed space, which was depressurized under vacuum, and then, a hole was drilled in the secondary battery to diffuse the generated gas into the closed space accommodating the secondary battery, and then, a sample was taken. Therefore, a jig is needed to enclose the entire exterior of the secondary battery to form a closed space for accommodating the secondary battery, and this jig is required to have a form conforming to the specification and shape of each different type of the secondary batteries released for various purposes (EV, ESS, mobile phone, etc.). That is, in the conventional gas collecting apparatus, since the secondary battery has various specifications such as area, thickness, etc., it is necessary to replace the jig whenever the shape and specification of the secondary battery to be inspected are changed.

In addition, in order to remove gases other than the sample gas formed in the closed space after the closed space was formed, a vacuum pump, an inert gas injecting apparatus and the like were required as separate apparatuses.

<CIT> discloses a technique concerned with 'an apparatus and a method for collecting gas generated in a secondary battery'.

<CIT> describes a device for automatically collecting gas generated in a secondary battery comprising a plurality of battery holders in which a plurality of secondary batteries are mounted, a battery holder tray in which the plurality of battery holders are placed, a collecting unit.

<CIT> describes an apparatus for detecting the sealability of a lithium ion cell comprising a container which is filled with a detecting liquid, a clamp, and a high-pressure-gas joint member.

<CIT> describes a gas extraction system of a small secondary battery comprising an upper and a lower battery jig unit for extracting gas inside a secondary battery, a vacuum unit, a gas extraction unit, and an air clean unit for discharging the remaining gas to the outside. <CIT> describes a system for extracting a gas of a medium and large secondary battery. The invention is defined in the independent claim.

It is an object of the present invention to provide a secondary battery internal gas-collecting apparatus, and more particularly, a secondary battery internal gas-collecting apparatus capable of easily collecting gas inside a secondary battery regardless of the specification and shape of the secondary battery.

The technical problems to be solved by the present invention are not limited to the technical problems as mentioned above, and other technical problems not mentioned will be clearly understood from the following description by those skilled in the art to which the present invention pertains.

A secondary battery internal gas-collecting apparatus of the present invention is defined in claim <NUM>. Preferred embodiments are defined in dependent claims <NUM>-<NUM>.

The secondary battery internal gas-collecting apparatus of the present invention can be utilized consistently for secondary batteries of all sizes regardless of a change in the specifications of the batteries.

The secondary battery internal gas-collecting apparatus of the present invention immediately collects gas inside a battery case without requiring a process of diffusing the gas in a separate chamber, thereby reducing a space for gas diffusion. Therefore, since the gas generated in the secondary battery can be collected in a smaller space, it is possible to increase the efficiency of analysis by collecting a high concentration of gas.

A pressing jig part of the secondary battery internal gas-collecting apparatus of the present invention contacts and presses only a local area of a battery case, and therefore, even if the jig is coupled to the secondary battery, the secondary battery has an exposed area that is not coupled to the jig. This exposed area can be used to connect accessory parts for various analyses.

The secondary battery internal gas-collecting apparatus of the present invention securely fixes a pressing jig part to only one surface of a battery case, and therefore, even if the shape and size of the secondary battery changes during the analysis, it is possible to smoothly collect the gas without replacing the jig.

Even if the secondary battery internal gas-collecting apparatus of the present invention is damaged by ignition of the secondary battery, only a pressing jig part or a sealing part needs to be replaced, thereby reducing the maintenance cost of the apparatus.

In the case of an O-ring applied to the structure of the secondary battery internal gas-collecting apparatus of the present invention, its area is <NUM> to <NUM> times smaller than that of the O-ring used in the conventional collecting apparatuses, thereby effectively improving leakage due to the O-ring.

A secondary battery internal gas-collecting apparatus of the present invention is the apparatus for collecting gas generated in a secondary battery comprising an electrode assembly and a rigid battery case accommodating the electrode assembly therein, wherein the apparatus comprises: a pressing jig part for pressing one surface of the battery case; a sealing part inserted between the pressing jig part and the one surface of the battery case; and a fixing unit for fixing the pressing jig part and the battery case in a state that the sealing means is inserted between the pressing jig part and the battery case, wherein the pressing jig part may be provided with a gas collecting pipe through which the gas generated inside the battery case flows.

In the secondary battery internal gas-collecting apparatus of the present invention, when the one surface of the battery case is referred to as a first surface, and the other surface of the battery case facing the first surface is referred to as a second surface, the fixing unit may include: a supporting jig part contacting with the second surface to support the secondary battery; a first plate to which the pressing jig part is fixed and which faces the first surface at a position spaced apart therefrom; a second plate to which the supporting jig part is fixed and which faces the second surface at a position spaced apart therefrom; and a pillar part coupled to the first plate and the second plate so that the first plate and the second plate maintain a certain distance from each other.

In the secondary battery internal gas-collecting apparatus of the present invention, the second plate may be provided with a jig guide hole in which the supporting jig part is inserted so as to be movable in a direction perpendicular to the first surface with respect to the second plate; and a locking means for fixing a relative position of the supporting jig part with respect to the second plate.

In the secondary battery internal gas-collecting apparatus of the present invention, a gas discharging pipe for flowing the gas discharged through the gas collecting pipe to an external analysis apparatus may be provided inside the first plate; the pressing jig part may be in contact with and coupled to the first plate; the gas collecting pipe may be a gas flow path formed inside the pressing jig part; an inlet of the gas collecting pipe may be formed to face the first surface; and an outlet of the gas collecting pipe may be formed on a contacting surface between the first plate and the pressing jig part so as to face an inlet of the gas discharging pipe.

In the secondary battery internal gas-collecting apparatus of the present invention, the pillar part extends in a direction perpendicular to the first surface and is provided in plural, wherein one end of the pillar part may be coupled to the first plate, and the other end of the pillar part may be coupled to the second plate.

In the secondary battery internal gas-collecting apparatus of the present invention, the pillar part includes a first pillar part and a second pillar part, wherein a virtual line connecting the first pillar part and the second pillar part on a virtual plane including the secondary battery, the first pillar part and the second pillar part and being parallel to the first surface may penetrate the secondary battery.

In the secondary battery internal gas-collecting apparatus of the present invention, it further includes a punching part for drilling a ventilating hole on the first surface of the battery case for discharging the gas, wherein the punching part is coupled to a surface of the pressing jig part opposite to a surface of the pressing jig part contacting the secondary battery; and a needle hole penetrating the inside of the pressing jig part may be formed in the pressing jig part so that a needle provided in the punching part protrudes from the surface of the pressing jig part contacting the secondary battery.

In the secondary battery internal gas-collecting apparatus of the present invention, an outlet of the needle hole through which the needle protrudes and an inlet of the gas collecting pipe through which the gas flows in may be formed at the same position.

In the secondary battery internal gas-collecting apparatus of the present invention, the needle hole is formed to penetrate the pressing jig part so as to connect the surface of the pressing jig part facing the battery case and the surface of the pressing jig part to which the punching part is coupled; the punching part is detachable; and the gas inside the secondary battery can be collected through the needle hole in a state that the punching part is separated from the pressing jig part.

In the secondary battery internal gas-collecting apparatus of the present invention, a ventilating hole for discharging the gas generated inside the secondary battery may be formed in the one surface of the battery case; the sealing part may be an O-ring; and the sealing part may be disposed such that the ventilating hole is located inside a circle of the O-ring.

In the secondary battery internal gas-collecting apparatus of the present invention, the sealing part may include one or more of silicone rubber, viton, natural rubber and synthetic rubber as a flexible material.

Hereinafter, the configuration and function of the secondary battery internal gas-collecting apparatus of the present invention will be described in detail with reference to <FIG>.

<FIG> is a plan view showing a state in which a secondary battery is coupled to a secondary battery internal gas-collecting apparatus according to one embodiment of the present invention. <FIG> is a plan view showing a state in which a secondary battery is not mounted to the secondary battery internal gas-collecting apparatus in <FIG>. <FIG> is a perspective view showing the secondary battery internal gas-collecting apparatus in <FIG>. <FIG> is a conceptual view showing an arranged relationship of a pillar part of the secondary battery internal gas-collecting apparatus in <FIG>. <FIG> is a cross-sectional view showing a cross-section A-A in <FIG>. <FIG> is a cross-sectional view showing a gas flow in the secondary battery internal gas-collecting apparatus in <FIG>. <FIG> is a plan view showing another embodiment of a secondary battery internal gas-collecting apparatus of the present invention.

The secondary battery internal gas-collecting apparatus of the present invention may be used for collecting gas generated in a secondary battery <NUM> comprising an electrode assembly <NUM> and a rigid battery case <NUM> for accommodating the electrode assembly <NUM> therein. That is, in the secondary battery internal gas-collecting apparatus of the present invention, the battery case <NUM> constituting an outer shape has a fixed volume and may be a rigid material. Specifically, the battery case <NUM> may be made of a stainless steel, and may have a shape that is maintained even when the pressure inside and outside the battery case <NUM> changes. Therefore, when an outer surface of the battery case <NUM> is pressed with a pressing jig part <NUM>, the battery case <NUM> withstands it, and the outer surface of the battery case <NUM> and the pressing jig part <NUM> may be in close contact with each other. The secondary battery <NUM> used in the apparatus of the present invention may have an outer shape formed of, for example, a prismatic or cylindrical hard case.

As shown in <FIG>, the secondary battery internal gas-collecting apparatus of the present invention may comprise: a pressing jig part <NUM> for pressing one surface of the battery case <NUM>, a sealing part <NUM> inserted into between the pressing jig part <NUM> and the one surface of the battery case <NUM>, and a fixing unit for fixing the pressing jig part <NUM> and the battery case <NUM> in a state that the sealing means is inserted between the pressing jig part <NUM> and the battery case <NUM>.

One surface of the battery case <NUM> facing the pressing jig part <NUM> is defined as a first surface, and the other surface of the battery case <NUM> facing the first surface is defined as a second surface.

As shown in <FIG> and <FIG>, the fixing unit may include: a supporting jig part <NUM> contacting the second surface to support the secondary battery <NUM>; a first plate <NUM> to which the pressing jig part <NUM> is fixed and which faces the first surface at a position spaced apart therefrom; a second plate <NUM> to which the supporting jig part <NUM> is fixed and which faces the second surface at a position spaced apart therefrom; and a pillar part <NUM> coupled to the first plate <NUM> and the second plate <NUM> so that the first plate <NUM> and the second plate <NUM> maintain a certain distance from each other.

The supporting jig part <NUM> may apply a force to the second surface, which is a surface opposite to the first surface of the battery case <NUM> which is pressed by the pressing jig part <NUM>, in a direction opposite to a direction of the force applied by the pressing jig part <NUM> to the secondary battery <NUM>, with the secondary battery <NUM> interposed therebetween. That is, the secondary battery <NUM> may be sandwiched between the pressing jig part <NUM> and the supporting jig part <NUM> and be fixed in place. A relative spacing between the pressing jig part <NUM> and the supporting jig part <NUM> may be adjusted, and the secondary battery <NUM> can be fixed between the pressing jig part <NUM> and the supporting jig part <NUM> by adjusting the spacing according to the size of the secondary battery <NUM>.

The spacing between the pressing jig part <NUM> and the supporting jig part <NUM> may be adjusted according to the specification of the secondary battery <NUM>. Since a spacing between the first plate <NUM> and the second plate <NUM> is always constant, the spacing between the pressing jig part <NUM> and the supporting jig part <NUM> cab be adjusted by moving the pressing jig part <NUM> in a direction perpendicular to the first surface with respect to the first plate <NUM>, or by moving the supporting jig part <NUM> in a direction perpendicular to the first surface with respect to the second plate <NUM>. Since a gas collecting pipe <NUM>, a punching part <NUM>, etc. may be coupled to the pressing jig part <NUM>, it may be desirable to adjust the spacing by moving the supporting jig part <NUM>.

Specifically, the second plate <NUM> may be provided with a jig guide hole <NUM> in which the supporting jig part <NUM> is inserted so as to be movable in a direction perpendicular to the first surface with respect to the second plate <NUM>; and a locking means <NUM> for fixing a relative position of the supporting jig part <NUM> with respect to the second plate <NUM>.

The jig guide hole <NUM> is formed to penetrate the second plate <NUM> in a direction perpendicular to the first surface, and the supporting jig part <NUM> can be guided and moved by the jig guide hole <NUM>.

The locking means <NUM> is provided on a surface opposite to a surface of the second plate <NUM> facing the battery case <NUM>, and may fix the supporting jig part <NUM> by tightening the side surface of the supporting jig part <NUM>.

The pillar part <NUM>, which fixes the first plate <NUM> and the second plate <NUM> so that the relative distance between them is always constant, extends in a direction perpendicular to the first surface, and may be provided in plural. One end of the pillar part <NUM> may be coupled to the first plate <NUM>, and the other end of the pillar part <NUM> may be coupled to the second plate <NUM>.

As shown in <FIG>, when the pillar part <NUM> includes a first pillar part <NUM> and a second pillar part <NUM>, a virtual line connecting the first pillar part <NUM> and the second pillar part <NUM> on a virtual plane including the secondary battery, the first pillar part <NUM> and the second pillar part <NUM> and being parallel to the first surface may penetrate the secondary battery <NUM>. That is, the first pillar part <NUM> and the second pillar part <NUM> may be disposed to interpose the secondary battery <NUM> therebetween.

Since the secondary battery internal gas-collecting apparatus of the present invention does not accommodate the secondary battery <NUM> in an enclosed space, but fixes the jigs through the pillar part <NUM>, the side surface of the battery case <NUM> may be open to the outside. That is, since the apparatus is not a structure in which the jig encloses the entire secondary battery <NUM>, it may be easy to directly couple additional separate equipment (charger-discharger, compactor, insulating material, temperature sensor, etc.) to the secondary battery <NUM>. Therefore, it is possible to collect not only the gas at the time of connecting a secondary battery internal gas-analyzing apparatus of the present invention to the secondary battery <NUM>, but also the gas generated in real time for each change in voltage, temperature or elapsed time inside the secondary battery <NUM>.

As shown in <FIG>, the secondary battery internal gas-collecting apparatus of the present invention may further include a punching part <NUM> for drilling a ventilating hole <NUM> for discharging the gas on the first surface of the battery case <NUM>. The punching part <NUM> may be coupled to a surface of the pressing jig part <NUM> opposite to a surface of the pressing jig part <NUM> contacting the secondary battery <NUM>. A needle hole <NUM> penetrating an inside of the pressing jig part <NUM> may be formed in the pressing jig part <NUM> so that a needle <NUM> provided in the punching part <NUM> protrudes from a surface of the pressing jig part <NUM> contacting the secondary battery <NUM>.

Specifically, the punching part <NUM> may include a needle <NUM> for drilling the ventilating hole <NUM> in the battery case <NUM>, a body part <NUM> having one end to which the needle <NUM> is fixed and having a diameter larger than a diameter of the needle <NUM>, a button (not shown) connected to the other end of the body part <NUM> to press the body part <NUM>, and an elastic member (not shown) providing a restoring force for the body part <NUM> to move the body part <NUM> to its original position after the needle <NUM> forms the ventilating hole <NUM> by pressing the body part <NUM>. A portion of the body part <NUM> may be inserted into the needle hole <NUM> formed in the pressing jig part <NUM>, and the body part <NUM> may reciprocate along the needle hole <NUM>. The needle hole <NUM> may be formed to penetrate the pressing jig part <NUM> in a direction perpendicular to a surface of the pressing jig part <NUM> facing the battery case <NUM>. A diameter of some sections of the needle hole <NUM> into which the body part <NUM> is inserted is formed to be substantially the same as a diameter of the body part <NUM>, and a sealing member (not shown) may be inserted between an inner surface of the needle hole <NUM> and a side surface of the body part <NUM>. A groove into which the sealing member is inserted may be formed in the body part <NUM>.

The needle <NUM> protrudes to an inlet of the needle hole <NUM> formed on a surface of the pressing jig part <NUM> facing the battery case <NUM> to form a ventilating hole <NUM> in the battery case <NUM>. The inlet of the needle hole <NUM> formed on the surface of the pressing jig part <NUM> facing the battery case <NUM> may be the same hole as an inlet of the gas collecting tube <NUM>, and the needle hole <NUM> and the gas collecting tube <NUM> may share some sections. That is, an outlet of the needle hole <NUM> through which the needle <NUM> protrudes and an inlet of the gas collecting pipe <NUM> through which gas flows in may be formed at the same position. Since the ventilating hole <NUM> formed in the battery case <NUM> is formed by the needle <NUM> protruding from the inlet of the gas collecting tube <NUM>, the ventilating hole <NUM> and the inlet of the gas collecting tube <NUM> can naturally face each other without a separate position alignment.

The pressing jig part <NUM> may be provided with a gas collecting pipe <NUM> through which the gas generated in the battery case <NUM> flows. The gas collecting pipe <NUM> may be a flow path through which the gas formed inside the pressing jig part <NUM> flows. An inlet of the gas collecting pipe <NUM> may be formed on a surface of the pressing jig part <NUM> facing the battery case <NUM>. Therefore, the gas discharged from the secondary battery <NUM> flows into the inlet of the gas collecting pipe <NUM>, and the gas introduced into the gas collecting pipe <NUM> may be discharged to an external analysis apparatus via the gas collecting pipe <NUM>.

As an embodiment, as shown in <FIG>, a gas discharging pipe <NUM> for flowing the gas discharged through the gas collecting pipe <NUM> to an external analysis apparatus may be provided inside the first plate <NUM>. In a state that the pressing jig part <NUM> and the first plate <NUM> are contacted and coupled to each other, an outlet of the gas collecting pipe <NUM> may be formed on a contacting surface between the first plate <NUM> and the pressing jig part <NUM> so as to face an inlet of the gas discharging pipe <NUM>. Therefore, the gas discharged through the pressing jig part <NUM> may be delivered to an external analysis apparatus via the gas discharging pipe <NUM> formed inside the first plate <NUM>. That is, the gas generated in the electrode assembly <NUM> may flow through the gas collecting pipe <NUM> of the pressing jig part <NUM> and the gas discharging pipe <NUM> of the first plate <NUM> to an external analysis apparatus. The secondary battery internal gas-collecting apparatus of the present invention basically collects the gas inside the secondary battery, but on the contrary, it is possible to analyze a change in the state of the secondary battery by injecting external air into the secondary battery in a reverse direction of the path.

A fastening part 321a protruding from a surface of the first plate <NUM> may be provided at an outlet of the gas discharging pipe <NUM> so as to facilitate the fastening of a pipe such as a hose.

The sealing part <NUM> may be an O-ring. The sealing part <NUM> may be disposed such that the ventilating hole <NUM> is located inside a circle of the O-ring. The sealing part <NUM> may include one or more of silicone rubber, viton, natural rubber and synthetic rubber as a flexible material. The sealing part <NUM> is directly exposed to the gas generated in the secondary battery <NUM>, and thus, its material may preferably have properties such as corrosion resistance, heat resistance, abrasion resistance and chemical resistance. When the sealing part <NUM> formed of a flexible material is pressed by the pressing jig part <NUM>, it may be deformed to fill and seal a gap between the sealing part <NUM> and the pressing jig part <NUM> and a gap between the sealing part <NUM> and the battery case <NUM>.

As another embodiment, as shown in <FIG>, the punching part <NUM> is detachable, and the gas inside the secondary battery can be collected through the needle hole <NUM> in a state that the punching part <NUM> is separated from the pressing jig part <NUM>. The needle hole <NUM> may be formed to penetrate the pressing jig part <NUM> so as to connect a surface of the pressing jig part <NUM> facing the battery case <NUM> and a surface of the pressing jig part <NUM> to which the punching part <NUM> is coupled; and the gas in the secondary battery <NUM> is introduced into an outlet of the needle hole <NUM> formed on a surface of the pressing jig part <NUM> facing the battery case <NUM>, and a pipe such as a hose connected to an external analysis apparatus is coupled to an inlet of the needle hole <NUM> formed on a surface of the pressing jig part <NUM> to which the punching part <NUM> has been coupled, so that the gas can be delivered to the external analysis apparatus.

Although embodiments according to the present invention have been described above, it will be understood that the embodiments are merely exemplary, and various modifications and other embodiments having equivalent scope can be made from the above embodiments by those skilled in the art. Therefore, the true technical scope of the present invention to be protected should be defined by the following claims.

Claim 1:
A secondary battery internal gas-collecting apparatus for collecting gas generated in a secondary battery (<NUM>) including an electrode assembly (<NUM>) and a rigid battery case (<NUM>) accommodating the electrode assembly (<NUM>) therein, the apparatus comprising:
a pressing jig part (<NUM>) for pressing one surface of the battery case (<NUM>), wherein the pressing jig part (<NUM>) is provided with a gas collecting pipe (<NUM>) through which the gas generated inside the battery case (<NUM>) flows,
characterized by
a sealing part (<NUM>) inserted between the pressing jig part (<NUM>) and the one surface of the battery case (<NUM>); and
a fixing unit for fixing the pressing jig part (<NUM>) and the battery case (<NUM>) in a state that the sealing part (<NUM>) is inserted between the pressing jig part (<NUM>) and the battery case (<NUM>),
wherein the one surface of the battery case (<NUM>) is a first surface, and the other surface of the battery case (<NUM>) facing the first surface is a second surface, and
the fixing unit comprises:
a supporting jig part (<NUM>) contacting the second surface to support the secondary battery (<NUM>);
a first plate (<NUM>) to which the pressing jig part (<NUM>) is fixed and which faces the first surface at a position spaced apart therefrom;
a second plate (<NUM>) to which the supporting jig part (<NUM>) is fixed and which faces the second surface at a position spaced apart therefrom; and
a pillar part (<NUM>) coupled to and fixing the first plate (<NUM>) and the second plate (<NUM>) so that the first plate (<NUM>) and the second plate (<NUM>) maintain a certain distance from each other, wherein the pillar part (<NUM>) extends in a direction perpendicular to the first surface.