Secondary battery and method for supplementing electrolyte of secondary battery

1. A secondary battery comprising:

a battery case comprising an accommodation part accommodating an electrode and an electrolyte therein; and

a sealing member for additionally injecting the electrolyte, which is disposed on a portion of the battery case to additionally inject the electrolyte into the accommodation part of the battery case and seals an injection portion,

wherein the sealing member for additionally injecting the electrolyte passes through the inside and outside of the battery case so that the electrolyte is injected through a penetrated portion of the sealing member,

wherein the sealing member for additionally injecting the electrolyte is provided as a thermoplastic member so that the injection portion is sealed by applying heat, and

wherein the thermoplastic member is made of a silicone sealant,

wherein, in the sealing member for additionally injecting the electrolyte, an outer part of the sealing member with respect to the accommodation part of the battery case is made of the silicone sealant to seal the injection portion by applying heat, and an inner part of the sealing member is made of silicone rubber to seal the injection portion through self-contracting force thereof.

2. The secondary battery of claim 1 , wherein the sealing member for additionally injecting the electrolyte further comprises a heat dissipation member disposed between the outer part and the inner part to block heat transfer between the outer part and the inner part.

3. The secondary battery of claim 1 , wherein the battery case further comprises a protrusion end protruding from each of inner and outer surfaces of the battery case in a direction of the sealing member for additionally injecting the electrolyte to support the sealing member for additionally injecting the electrolyte, thereby preventing the sealing member from being separated from the battery case.

4. A method for supplementing an electrolyte of a secondary battery, the method comprising:

an injection preparation process of allowing an injection needle to pass through a sealing member for additionally injecting the electrolyte, which passes through the inside and outside of a battery case and is formed on a portion of the battery case so that the injection needle passes through a penetrated portion of the sealing member to inject the electrolyte;

an injection process of additionally injecting the electrolyte into an accommodation part of the battery case, in which an electrode assembly and the electrolyte are accommodated, through the injection needle; and

a sealing process of sealing the portion of the sealing member, through which the injection needle passes, after the injection needle is removed from the sealing member for additionally injecting the electrolyte,

wherein, in the injection preparation process, the injection needle passes through the sealing member for additionally injecting the electrolyte after heat is applied to the sealing member provided as a thermoplastic member so that the injection needle easily passes through the sealing member, and

in sealing process, heat is applied to the sealing member for additionally injecting the electrolyte provided as a thermoplastic member to seal the portion of the sealing member, through which the injection needle passes.

5. The method of claim 4 , wherein, in the sealing process, heat is applied to the sealing member for additionally injecting the electrolyte made of a silicone sealant to seal the penetrated portion.

6. The method of claim 4 , wherein, in the sealing process, the sealing member for additionally injecting the electrolyte is made of silicone rubber to seal the portion of the sealing member, through which the injection needle passes, by self-contracting force of the silicone rubber when the injection needle is removed from the sealing member for additionally injecting the electrolyte.

7. The method of claim 5 , further comprising a tape attaching process of attaching a sealing tape to an outer surface of the sealing member for additionally injecting the electrolyte.

8. The method of claim 7 , wherein, in the tape attaching process, the sealing tape is attached before the injection preparation process,

in the injection preparation process, the injection needle passes through the sealing member for additionally injecting the electrolyte after a portion or the whole of the sealing tape is separated from the sealing member for additionally injecting the electrolyte, and

in the sealing process, the portion of the sealing tape, which is separated from the sealing member for additionally injecting the electrolyte, is attached again to the sealing member for additionally injecting the electrolyte to additionally seal the sealing member after the injection needle is removed from the sealing member for additionally injecting the electrolyte.

9. The method of claim 4 , wherein, in the sealing process, an inner part of the sealing member for additionally injecting the electrolyte, which is made of silicone rubber, with respect to the accommodation part of the battery case seals the portion, through which the injection needle passes, by self-contracting force of the silicone rubber when the injection needle is removed, and

heat is applied to an outer part of the sealing member for additionally injecting the electrolyte, which is made of a silicone sealant, to seal the penetrated portion of the sealing member.

10. The method of claim 6 , further comprising a tape attaching process of attaching a sealing tape to an outer surface of the sealing member for additionally injecting the electrolyte.

11. The method of claim 10 , wherein, in the tape attaching process, the sealing tape is attached before the injection preparation process,

in the injection preparation process, the injection needle passes through the sealing member for additionally injecting the electrolyte after a portion or the whole of the sealing tape is separated from the sealing member for additionally injecting the electrolyte, and

in the sealing process, the portion of the sealing tape, which is separated from the sealing member for additionally injecting the electrolyte, is attached again to the sealing member for additionally injecting the electrolyte to additionally seal the sealing member after the injection needle is removed from the sealing member for additionally injecting the electrolyte.