Lithium rechargeable battery and method of making the same
A lithium rechargeable battery having corrosion resistance and a method of making the same. In the lithium rechargeable battery including a metal case, a cap plate and terminals, a protective layer is formed on at least portions of surfaces of the metal case, the cap plate and the terminals, and the protective layer is formed of a protective layer forming composition comprising at least one hydrophobic compound selected from the group consisting of substituted or unsubstituted 1,2,3-benzotriazole, alkoxysilance having 1 to 20 carbons, vinylakoxy silane having 1 to 20 carbons, and (meth)acryl silane, and chromic oxide.
1. A lithium rechargeable battery including a metal case, a cap plate and terminals, a protective layer being formed on at least portions of surfaces of the metal case, the cap plate and the terminals, and the protective layer is formed of a protective layer forming composition comprising at least one hydrophobic compound selected from the group consisting of substituted or unsubstituted 1,2,3-benzotriazole, alkoxysilane having 1 to 20 carbons, vinylalkoxysilane having 1 to 20 carbons, and (meth)acryl silane; and chromic oxide.
2. The lithium rechargeable battery of claim 1 , the protective layer comprising the chromic oxide and the hydrophobic compound in a weight ratio of 0.01:1 to 1:1 (w/w).
3. The lithium rechargeable battery of claim 1 , the vinylalkoxysilane including at least one selected from the group consisting of vinylmethoxysilane, vinyltris(2-methoxyethoxy)silane and vinylethoxysilane.
4. The lithium rechargeable battery of claim 1 , the protective layer forming composition further comprising a solvent and the hydrophobic compound is contained in a concentration of 0.1 g/L to 10 g/L.
5. The lithium rechargeable battery of claim 1 , the protective layer forming composition having a pH level in a range of 3.0 to 4.5.
6. The lithium rechargeable battery of claim 1 , the protective layer having a thickness in a range of 0.01 to 0.1 μm.
7. The lithium rechargeable battery of claim 1 , the protective layer being formed by immersing or spraying the protective layer forming composition.
8. A method of making a lithium rechargeable battery, the method comprising:
forming a protective layer by immersing or spraying a protective layer forming composition to at least portions of surfaces of a metal case, a cap plate and terminals; and
drying the protective layer,
the protective layer forming composition comprising at least one hydrophobic compound selected from the group consisting of substituted or unsubstituted 1,2,3-benzotriazole, alkoxysilane having 1 to 20 carbons, vinylalkoxysilane having 1 to 20 carbons, and (meth)acryl silane; and chromic oxide.
9. The lithium rechargeable battery of claim 8 , the chromic oxide and the hydrophobic compound, being contained in the protective layer in a weight ratio of 0.01:1 to 1:1 (w/w).
10. The lithium rechargeable battery of claim 8 , the protective layer forming composition having a pH level in a range of 3.0 to 4.5.
11. The lithium rechargeable battery of claim 8 , the drying of the formed protective layer being performed at 60 to 80° C. for 20 minutes to one hour.