Sealing member and battery comprising the same

A sealing member and a battery comprising the sealing member are provided. The sealing member comprises a sealing part, an operation part having a supporting portion, an operation protrusion disposed on an upper surface of the supporting portion, and a deformable leg depending from a bottom surface of the supporting portion. The sealing member also comprises a connecting part connecting the sealing part and operation part. The sealing part has a maximum diameter greater than that of the connecting part.

RELATED APPLICATIONS

This application claims priority and benefits of Chinese Patent Application No. 201220502764.7, filed with State Intellectual Property Office, P. R. China on Sep. 27, 2012, the entire content of which is incorporated herein by reference.

FIELD

The present disclosure generally relates to the battery field, and, more particularly, to a sealing member for a battery and a battery including the sealing member.

BACKGROUND

Batteries such as lithium ion batteries are widely used due to their small volume, high energy density, non-pollution, etc. Active materials in the battery need to be activated by a pre-charging process (also known as a transformation process), before the battery can work normally. In the transformation process, gas may be generated inside the battery. In the existing transformation process, the gas sometimes cannot be successfully discharged from the interior of the battery, or the moisture in the environmental air may be brought into the battery, causing the moisture content of the electrolyte to be over a certain limit. If the gas generated in the transformation process cannot be discharged successfully from the battery, gas expansion will occur. Gas expansion in the battery may seriously affect the properties and operation of the battery. Thus, in the transformation process, whether the gas generated inside the battery can be discharged successfully via a sealing structure of an injection hole has a great influence in the performance of the battery.

SUMMARY

In one aspect, a sealing member comprises a sealing part, an operation part having a supporting portion, an operation protrusion disposed on an upper surface of the supporting portion, a deformable leg depending from a bottom surface of the supporting portion, and a connecting part connecting the sealing part and the operation part. The sealing part has a maximum diameter greater than that of the connecting part.

In another aspect, a battery comprises a shell, a cover plate having an injection hole and configured to define a cavity with the shell, a core and electrolyte in the cavity, and a sealing member. The sealing member comprises a sealing part, an operation part having a supporting portion, an operation protrusion disposed on an upper surface of the supporting portion, a deformable leg depending from a bottom surface of the supporting portion, and a connecting part connecting the sealing part and the operation part. The deformable leg is supported on the upper surface of the cover plate. The connecting part is disposed in the injection hole. The sealing part seals the injection hole and is adapted to open the injection hole upon pressing the operation part.

In yet another aspect, a batter comprises a shell, a cover plate having an injection hole and configured to define a cavity with the shell, a core and electrolyte in the cavity, and a sealing member. The sealing member comprises a sealing part, an operation part having a supporting portion, an operation protrusion disposed on an upper surface of the supporting portion, a deformable leg depending from a bottom surface of the supporting portion, and a connecting part connecting the sealing part and the operation part. The sealing part has a maximum diameter greater than that of the connecting part.

DETAILED DESCRIPTION

Reference will be made in detail to embodiments of the present disclosure. The embodiments described herein with reference to drawings are explanatory, illustrative, and used to generally understand the present disclosure.

In the specification, unless specified or limited otherwise, relative terms such as “central”, “longitudinal”, “lateral”, “front”, “rear”, “right”, “left”, “inner”, “outer”, “lower”, “upper”, “horizontal”, “vertical”, “above”, “below”, “up”, “top”, “bottom” as well as derivative thereof (e.g., “horizontally”, “downwardly”, “upwardly”, etc.) should be construed to refer to the orientation as then described or as shown in the drawings under discussion. These relative terms are for convenience of description and do not require that the present disclosure be constructed or operated in a particular orientation.

As electric devices, such as electric vehicles and energy storage stations require batteries with higher and higher capacity, the sealing structure of a conventional low-capacity mobile lithium battery may not meet the manufacturing requirement of a high-capacity power battery. Existing high-capacity sealing structures comprise a rubber valve coupled with the cover plate of the battery. The rubber valve is capable of releasing the gas generated inside the battery rapidly and completely, while ensuring the interior of the battery is separated from the outside air, and thus gas expansion can be avoided or minimized. For example, Chinese Patent No. CN201498559U discloses such a battery sealing structure. However, the sealing structure has the following problems. 1) A small diameter through hole is disposed in the bottom of the rubber valve and configured to release gas inside the battery. When the electrolyte is injected into the battery completely, the rubber valve is inserted into the injection hole to seal the battery. When the pressure inside the battery reaches a predetermined pressure, the gas may be discharged outside the battery automatically. However, during the gas discharging process, the switch-on pressure of the rubber valve is not stable, and gas release under low pressure may occur, which further causes a sealing failure. Further, because rubber is flexible, the through hole with the small diameter can be deflected or deformed easily under a pressure, or become blocked by a foreign matter. Thus, the gas inside the battery may not be released successfully. 2) The contact area between an upper protrusion of the cover plate and the cover plate is so small that the connection therebetween may not be tight enough, which is detrimental for the sealing effect of the battery. 3) It is hard to insert the rubber valve into the injection hole, which creates difficulties in the assembling process and inconvenience for the users.

Embodiments of the present disclosure seek to solve at least one of the problems existing in the related art, and provide a sealing member and a battery comprising the sealing member. The sealing member can release the gas from the battery under pressing action, and has a reliable sealing ability and is low in manufacturing cost.

According to embodiments of a first broad aspect of the present disclosure, a sealing member for a battery is provided. The sealing member comprises a sealing part; an operation part having a supporting portion, an operation protrusion is disposed on an upper surface of the supporting portion, and a deformable leg depends from a bottom surface of the supporting portion. The sealing member also comprises a connecting part connecting the sealing part and the operation part, in which the sealing part has a maximum diameter greater than that of the connecting part.

In some embodiments, the sealing member is made of elastic materials. When the sealing member is inserted into an injection hole of the battery and no external force is applied on the sealing member, because the leg is longer than the connecting part, the leg tends to recover and moves upwardly, and thus the first sealing part is lifted up via the connecting part. Thus, the injection hole may be sealed after assembly of the battery, or the injection hole may be sealed rapidly after a gas release process.

When an external force is applied on the protrusion of the second sealing part, the leg is further compressed and the connecting part may move downwardly accordingly together with the first sealing member. When the first sealing part leaves the injection hole and does not contact with the cover plate of the battery, a gap may be formed between the cover plate and the sealing part. Then the gases inside the battery may be released through the gap.

When the external force applied on the protrusion is removed, the leg expands from being compressed and moves upwardly, and the connecting part and the first sealing part are both lifted up, then the injection hole is sealed by the first sealing part again.

In some embodiments, the deformable leg is longer than the connecting part.

In some embodiments, the sealing member is made of elastic materials.

In some embodiments, at least two deformable legs are distributed evenly at a periphery of the bottom surface of the supporting portion and spaced apart from each other. With the at least two deformable legs, the supporting portion may be supported more stably and the external force applied on the supporting portion may be distributed more uniformly thereon. Further, the gases released from the gap may further released to the exterior environment via a space between the deformable legs.

In some embodiments, the deformable leg has an arcuate free end surface.

In some embodiments, the sealing part comprises a truncated-cone-shaped portion connected with the connecting part. The truncated-cone-shaped portion may facilitate to seal the injection hole when the sealing part is lifted up and to leave the injection hole when the gas is released. Thereby, the gas release efficiency of the battery is improved. Further, the truncated-cone-shaped portion also facilitates to prevent water from entering into the battery via the injection hole.

In some embodiments, the sealing part comprises a guiding portion at a bottom thereof, and the guiding portion is connected to the truncated-cone-shaped portion. The guiding portion has an inverted and truncated cone shape. An upper surface of the guiding portion has the same diameter as that of a bottom surface of the truncated-cone-shaped portion, and the guiding portion has a length greater than that of the truncated-cone-shaped portion. With the guiding portion, the sealing member may be guided and inserted into the injection hole more easily.

In some embodiments, the sealing part is hollow. Because the sealing part is hollow, the sealing member may be pressed, extruded, or inserted into the injection hole more easily.

In some embodiments, a hole is formed in the sealing part and extended through the guiding portion in the lengthwise direction of the guiding portion. The hole is extended into the truncated-cone-shaped portion by a predetermined length and has a dome-shaped upper end, and a side wall surface of the hole is transitioned into a bottom surface of the guide portion via an arc dome-shaped upper end. With the hole, the sealing member may be extruded or pressed, which facilitates to process the sealing member and provides the sealing member with a stable structure and a strong supporting capability. Further, the dome-shaped upper end of the hole may prevent the sealing part from being over-lifted or damaged during the sealing process. With the transition arc at the bottom of the hole, the assembly for the sealing member is more flexible. Moreover, the transition arc prevents the sealing member from being damaged.

In some embodiments, the supporting portion is configured by a flat plate and a periphery edge of an upper surface of the supporting portion is rounded. When an external force is applied on the operation protrusion, the stress generated on an edge of the supporting portion may be reduced, thus avoiding problems, such as cracks.

In some embodiments, the operation protrusion is disposed at a center of the upper surface of the supporting portion and has a diameter less than that of the supporting portion, and the connecting part is concentric with the supporting portion and the sealing part. Specifically, the centers of the operation protrusion, the supporting portion, the connecting part and the sealing part are located in the same straight line.

In some embodiments, the deformable leg is configured as an arcuate block.

In some embodiments, the deformable leg is configured as a column having a circular cross section.

According to embodiments of a second broad aspect of the present disclosure, a battery is provided. The battery comprises a shell, a cover plate having an injection hole and configured to define a cavity with the shell, a core and electrolyte in the cavity, and a sealing member as described above. The deformable leg is supported on the upper surface of the cover plate, the connecting part is disposed in the injection hole, and the sealing part seals the injection hole.

In some embodiments, the connecting part has a diameter less than that of the injection hole, and the sealing part has a maximum diameter greater than that of the injection hole.

In some embodiments, a covering element is disposed on the cover plate and configured to seal the sealing member together with the cover plate.

According to embodiments of the present disclosure, the length of the deformable leg is greater than that of the connecting part, thus the deformable leg is in a compressive state (compressed onto the upper surface of the cover plate) after the sealing member is inserted in the injection hole. As the leg is elastic, it tends to recover. Thus, with the guide of the supporting portion, the connecting part together with the sealing part may be lifted up. As described above, the diameter of the sealing part is larger than that of the connecting part, so the injection hole may be blocked by the sealing part. In this way, the battery is sealed successfully.

When the sealing part is pressed, such as an external force is applied on the protraction, the deformable legs are further compressed and the first sealing part moves downwardly with the connecting part and leaves the cover plate. Then a gap may be formed between the cover plate and the first sealing part, and the gas inside the battery may be released via the gap successfully.

In addition, when the external force is removed, as the leg has a greater length than that of the connecting part, the leg tends to recover and the sealing part may be lifted up rapidly after the gas release process. In this way, the sealing part may block the injection hole again, thus the injection hole of the battery is sealed.

As described above, with the up and down movements of the connecting part in the injection hole, the sealing member fits with the battery accordingly, which prevents the external environment from influencing the interior of the battery. In some embodiments, the sealing part has a guiding portion. With the guiding portion, it is easier to insert the sealing member into the injection hole. In addition, the guide portion facilitates the fit between the sealing member and the injection hole, which reduces the manufacture cost of the battery, and realizes a stable and reliable sealing and gas release for the battery.

The sealing member according to embodiments of the present disclosure will be described with reference to the drawing below.

The sealing member may be used to seal the injection hole in the cover plate of a battery such as a lithium ion battery. Those skilled in the art that will appreciate that the battery includes a shell having at least one open end, a core disposed in the shell, electrolyte contained in the shell, and a cover plate configured to close the open end of the shell. The shell is generally made of aluminum or steel, and configured to contain the core and electrolyte. The shell may have one open end, and the current is led out from the open end. The shell may have two open ends, and the current is led out from the two open ends of the battery.

The opening in the open end of the shell may be formed in a shorter side of the shell, and the core is inserted into the shell vertically, and a portion of the core extended out of the opening is used as a terminal of the core, so that the current is extracted from the portion of the core.

Alternatively, the opening may be formed in a longer side of the battery, and the core is inserted into the shell horizontally. The portion of the core extended out of the opening is a wound arc edge of the core. The core is formed by stacking or winding a positive plate, a separator and a negative plate in turn. The structure and the manufacture of the core may be known in related art, thus detailed description thereof will be omitted herein.

Generally, an injection hole is formed in at least one cover plate of the battery. After the cover plate is welded with the shell, the electrolyte is fed into the shell via the injection hole. When the filling of the electrolyte is completed, a one-way sealing valve (member) is inserted into the injection hole. In this way, the injection hole, thereby the battery, is sealed, thus isolating the interior of the battery from the external environment, and preventing impurities and water entering into the battery from the external environment. Then the battery is subjected to a transformation process, in which the battery is charged for the first time. During the charging process, a lot of gas is generated and will be released out of the battery via the sealing member by applying a pressure. Generally, the gas may be generated only in the transformation process, and less gas is generated when the battery is charged in the subsequent process. Therefore after the transformation process, a covering element may be welded onto the cover plate and configured to seal the sealing valve (member) and thereby to further seal the injection hole. The covering element generally has a cylindrical projection on the center thereof and is made of metal.

Various improvements on the battery, particularly on the sealing member of the battery, are described in the present disclosure. The sealing member of the present disclosure will be described in detail below with reference toFIGS. 1-6.

It will be understood that the battery according to the present disclosure may refer to any suitable batteries, such as a lithium ion battery. As shown inFIGS. 1-6, a sealing member (may be referred to as “sealing valve”)6suitable for a battery according to embodiments includes a sealing part5, an operation part and a connecting part3connecting the sealing part5and operation part. The operation part has a supporting portion2. An operation protrusion1is disposed on an upper surface of the supporting portion2, and a deformable leg4depends from a bottom surface of the supporting portion2. The sealing part5has a maximum diameter greater than that of the connecting part3. In one embodiment, the sealing part5is longer than the connecting part3, in other words, the size of the sealing part5in the up and down direction inFIG. 3is larger than that of the connecting part3.

According to embodiments of the present disclosure, the sealing member6may be used to seal an injection hole8of a battery such as a lithium ion battery during the transformation process of the battery. Particularly the battery may be high in capacity, for example, a lithium ion power battery, or a lithium ion energy storage battery.

In some embodiments, the sealing member6is made of elastic materials, for example, non-metallic materials having good resilience. By way of example and without limitations, the sealing member6may be made of polytetrafluoroethylene (TPFE), ethylene propylene diene monomer (EPMD), and fluoride rubbers. In one embodiment, the sealing member6is integrally made of a rubber by using a molding process, such as an injection molding process.

In some embodiments, when the sealing member6is inserted into the injection hole8, the deformable leg4is supported onto the upper surface of the cover plate7, in other words, the deformable leg4is pressed onto the upper surface of the cover plate7under a pull from the connecting part3and the sealing part5.

In some embodiments, the operation protrusion1is disposed on the upper surface of the supporting portion2. An external force may be applied on the protrusion1, then a pressure brought by the external force on the supporting portion2may be buffered, which provides the supporting portion2with a better mechanical performance. By providing the operation protrusion1on the supporting portion2, the supporting portion2is avoided from blocking the injection hole8when the external force is applied. Thus, gas may be released successfully from the inside of the battery.

In one embodiment, as shown inFIG. 1, the operation protrusion1may be a projected portion extended out from the upper surface of the supporting portion2. There are no particularly limitations to the shape of the operation protrusion1. For example, the operation protrusion1may have a cross section of trigon (as shown inFIG. 5), square, and oval. In the embodiment shown inFIG. 1, the operation protrusion1is a cylinder, in which a diameter of a bottom surface of the cylinder is smaller than that of the supporting portion2. For example, the diameter of the bottom surface of the cylinder is about 50% to about 60% times of that of the supporting portion2, and the height of the cylinder is about 1 to about 1.5 times of that of the supporting portion2.

In some embodiments, the operation protrusion1is disposed on a center of the upper surface of the supporting portion2. In this way, the external force may be distributed on the supporting portion2uniformly. Specially, the centers of the operation protrusion1, the supporting portion2, the connecting part3, and the sealing part5are in the same straight line.

In some embodiments, as shown inFIG. 3, the supporting portion2pulls the connecting part3upwardly under the elastic action of the deformable leg4. In some embodiments, the diameter of the supporting portion2is greater than that of the injection hole8. The cross section of the supporting portion2may be square or oval. The thickness of the supporting portion2is not limited in the present disclosure, for example, the support portion2is 1.5 mm to 3 mm in thickness. In one embodiment, the supporting portion2is a flat plate. In another embodiment, the supporting plate may be a circular plate having a thickness of 2 mm.

In some embodiments, the supporting portion2has an arcuate free upper surface. When the external force is applied on the operation protrusion1, for example, the operation protrusion1is pressed by an operator, for example, the operation protrusion1is pressed by an operator, a strain generated on the edge of the supporting portion2may be reduced, thus avoiding cracking problems.

In some embodiments, when the sealing member6is inserted into the injection hole8, the sealing part5is located below the upper surface of the cover plate7, and the operation part is located above the upper surface of the cover plate7.

The shape of the connecting part3may be designed according to the shape of the injection hole8. Generally, the connecting part3is a cylinder having a diameter slightly smaller than that of the injection hole8. The connecting part3is movable (for example, movable upwardly or downwardly inFIG. 3) in the injection hole8, while gas may be released via a gap between the connecting part3and the cover plate7. In one embodiment, the connecting part3is disposed on the center of the bottom surface of the supporting portion2and the center of the upper surface of the sealing part5. The operation part may include one or more deformable legs4, and the deformable legs4are distributed evenly at a periphery of the bottom surface of the supporting portion2.

In some embodiments, the deformable leg4is located on the bottom surface of the supporting portion2and has a length greater than that of the connecting part3. In addition, the leg4is elastic. The supporting portion2normally pulls the connecting part3to move upwardly under the recovering elastic force of the deformable leg4, thus pulling the sealing part5upwardly and sealing the injection hole8accordingly. When the operation protrusion1is pressed by an external force, the elastic deformable leg4moves downwardly under the external force, and the sealing part5moves downwardly and is separated from the wall of the injection hole8. In this way, a gap may be formed between the first sealing part5and the cover plate, and the gas inside the battery may be released via the gap.

In some embodiments, the operation part includes one deformable leg4configured as a sleeve and disposed at the bottom surface of the supporting portion2. In this embodiment, the deformable leg4is capable of releasing gas therein. For example, a ventilation hole or a slot may be formed in the deformable leg4so that gas inside the leg may be released through the ventilation hole or the slot.

In some embodiments, the operation part includes a plurality of deformable legs4disposed evenly at a peripheral of the bottom surface of the supporting portion2and distributed symmetrically relative to the connecting part3. The deformable legs4are spaced apart from the connecting part3, so that the gas can be released from the intervals between adjacent deformable leg4. In this way, the supporting portion2is supported by the deformable legs4stably and uniformly on the cover plate of the battery

According to an embodiment of the present disclosure, the shape of the deformable leg4is not limited, which may be a cylinder (as shown inFIG. 6), a cone, a diamond and a truncated cone. In one embodiment, a cross-section of the deformable leg is a segment of circular ring, and the cross-section area of the deformable leg4is decreased gradually from up to down inFIGS. 1 and 2. In some embodiments, the deformable leg4has an arcuate free end surface. With the arcuate free end surface to be contacted with the upper surface of the cover plate7, so that damages to the cover plate7and the deformable legs4may be avoided. Further, the arcuate free end surface facilitates the supporting portion2to withstand the external force.

In one embodiment, the deformable leg4is configured as an arcuate block. Alternatively, the deformable leg4is configured as a column having a circular cross section.

In some embodiments, when the sealing member6is mounted to the cover plate7, the sealing part5is in the shell of the battery, and the maximum diameter of the sealing part5is greater than that of the injection hole8, so that the injection hole8is sealed by the sealing part5. There is no limit to the shape of the sealing part5, as long as the sealing part5can seal the injection hole8. In some embodiments, the sealing part5is hollow. During inserting the sealing part5through the injection hole8, the sealing part5may retract, thus facilitating the insertion of the sealing part5through the injection hole8.

In some embodiments, the sealing part5, i.e., the sealing element has a hollow structure. The hollow structure may locate along the central line of the sealing part5, and the size of the hollow structure may be designed according to practical requirement. For example, it is required the sealing member6may be extruded or pressed. During the assembly process, the first sealing part5may retracted to a smaller size, which facilitates the sealing member6to be inserted into the injection hole8.

In some embodiments, the sealing part5includes a truncated-cone-shaped portion51connected with the connecting part3. The diameter of the upper surface of the truncated-cone-shaped portion51may be the same as that of the connecting part3. With the truncated-cone-shaped portion51, it is more convenient to seal and open the injection hole8, thus improving the gas release efficiency of the battery. In addition, it prevents water from entering into the interior of the battery.

In some embodiments, the sealing part5includes a guiding portion52at the bottom thereof. The guiding portion5may have any shape having a guiding function, such as a cone. By providing the guiding portion52, it is more convenient to insert the sealing part5through the injection hole8.

The guiding portion5may have any shape having a guiding function, such as a cone. By providing the guiding portion52, it is more convenient to insert the sealing part5through the injection hole8.

As shown inFIG. 3, the guiding portion52is connected with the truncated-cone-shaped portion51. The guiding portion52has an inverted and truncated cone shape. An upper surface of the guiding portion52has the same diameter as that of a bottom surface of the truncated-cone-shaped portion51, and the guiding portion52has a length greater than that of the truncated-cone-shaped portion51. In one embodiment, a hole53is formed in the guiding portion52and extended through the guiding portion52in an up-down direction inFIG. 3, so that the sealing part5is configured to have a hollow structure. The hole is extended into the truncated-cone-shaped portion51so as to form dome-shaped upper end54, and a side wall surface of the hole53is transitioned into a bottom surface of the guide portion52via arc, thus facilitating the movement of the sealing part5. The length of the guiding portion52may be greater than that of the truncated-cone-shaped portion51, thus facilitating the assembly of the sealing member6. With the dome-shaped upper end54, the sealing member6has a stable structure and a strong supporting capability. Further, the dome-shaped upper end54may prevent the sealing part5from being overly moved upwards or damaged during sealing process. The side wall surface of the through hole53is transitioned into the bottom surface of the guide portion52via arc, thus the assembly of the sealing member6is more flexibly. Moreover, the transition arc prevents the sealing member6from being damaged.

A battery including the sealing member6described above may be explained below in detail.

As shown inFIGS. 3 and 4, the battery includes a shell (not shown), a cover plate7having an injection hole8and configured to define a cavity with the shell, a core (not shown) and electrolyte (not shown) contained in the cavity, and a sealing member which may the sealing member6described above. The deformable leg4is supported onto the upper surface of the cover plate7, the connecting part3is in the injection hole8, and the sealing part5is seals the injection hole8and adapted to open the injection hole8under pressing the operation part.

In some embodiments, the connecting part3has a diameter smaller than that of the injection hole8, and the sealing part5has a maximum diameter greater than that of the injection hole8.

In some embodiments, a covering element (not shown) is disposed on the cover plate7and configured to seal the sealing member6together with the cover plate7.

The sealing and gas release process of the battery according to embodiments of the present disclosure will be described below with reference toFIGS. 3 and 4.

As shown inFIG. 3, the battery is in a sealed state. When the sealing member6is mounted to the cover plate and no external force is applied on the sealing member6, the deformable legs4are deformed, i.e., the deformable legs4are compressed onto the upper surface of the cover plate. As the diameter of the connecting part3is smaller than that of the injection hole8, the connecting part3and the sealing part5are pulled upwards by the supporting portion2under the elastic force of the legs4. Because the maximum diameter of the sealing part5is larger than that of the injection hole8, the sealing part5seals the injection hole8when the sealing part5comes into contact with covering plate7.

As shown inFIG. 4, the battery is in a gas release state. When an external force is applied on the sealing member6, for example, the operation protrusion1is pressed by the external force, the deformable leg4is further compressed. The connecting part3and the sealing part5move downwardly. When the sealing member5is separated from the cover plate, a gap is formed between the sealing part5and the cover plate7thus opening the injection hole8, so that the gas inside the battery may be released via the gap.

When the external force applied on the operation protrusion1is removed, the sealing part5moves upwardly under the recovering elastic force of the deformable leg4. When the sealing part5comes into contact with the cover plate7, the injection hole8is sealed by the sealing part5again.

In embodiments of the present disclosure, the deformable leg4is in a deformed state (compressed onto the upper surface of the cover plate) after the sealing member6is mounted to the cover plate7. As the deformable leg4is deformable and tends to recover. The connecting part together with the sealing part is driven to move upward under the recovering elastic force of deformable legs. As described above, the diameter of the sealing part is larger than that of the connecting part, so the injection hole may be sealed by the sealing part.

When the sealing member is pressed, such as an external force is applied on the operation protrusion, the deformable legs are further compressed and the sealing part opens the injection hole. Then a gap may be formed between the cover plate and the sealing part, and the gas inside the battery may be released via the gap.

In addition, when the external force is removed, the deformable legs tend to recover from the deformed state and stretches upwardly, thus pulling the connecting part upwards. Then the sealing part may be moved upwards with the connecting part under the pulling of the deformable legs. In this way, the sealing part may seal the injection hole again, thus the battery is sealed.

As described above, with the upward and downward movements of the sealing member, the sealing member seals and opens the injection hole accordingly. With the guiding portion, it is easier to insert the sealing part through the injection hole.