Battery cell and battery module using the same

1. A battery cell, comprising:

a body;

at least one rail installed on the body;

at least one rail groove formed on a surface of the body on which the rail is not installed; and

at least one cooling hole in the rail,

wherein the cooling hole is opened to outside at the end of the rail and forms a path of a fluid,

wherein the rail has a cross section that is gradually extended toward an outside direction of the body,

wherein the cooling hole has a cross section that is gradually extended toward an outside direction of the body, and

wherein the rail groove has a cross section that is gradually extended toward an inside direction of the body.

2. A battery module, comprising:

a first battery cell having at least one first rail installed on a first body, at least one first rail groove formed on a surface on an opposite side of the first body where the first rail is not installed, and a first cooling hole in the first rail; and

a second battery cell having at least one second rail installed on a second body, at least one second rail groove formed on a surface on an opposite side of the second body where the second rail is not installed, and a second cooling hole in the second rail;

wherein the first rail slides along the second rail groove or the second rail slides along the first rail groove, such that the first battery cell and the second battery cell are joined to each other,

wherein the first cooling hole and the second cooling hole are opened to outside at the end of the first and second rail, respectively, and form paths of a fluid,

wherein the first rail and the second rail have cross sections that are gradually extended toward outside directions of the first body and the second body, respectively,

wherein the first cooling hole and the second cooling hole have cross sections that are gradually extended toward outside directions of the first body and the second body, respectively, and

wherein the first rail groove and the second rail groove have cross sections that are gradually extended toward inside directions of the first body and the second body, respectively.

3. The battery module of claim 2 , further comprising:

an aligning unit installed between the first rail and the second rail groove and between the second rail and the first rail groove so that slide driving of the first battery cell or the second battery cell is stopped at alignment positions of the first battery cell and the second battery cell.

4. The battery module of claim 3 , wherein the aligning unit includes:

an alignment groove formed at any one of the first rail and the second rail groove and any one of the second rail and the first rail groove; and

a stopper installed at the other one of the first rail and the second rail groove and the other one of the second rail and the first rail groove, in which the alignment groove is not formed.

5. The battery module of claim 4 , wherein the stopper further includes:

a ball installed at the other one of the first rail and the second rail groove and the other one of the second rail and the first rail groove, in which the alignment groove is not formed; and

an elastic body elastically supporting the ball.

6. The battery module of claim 4 , wherein the stopper is a leaf spring installed at the other one of the first rail and the second rail groove and the other one of the second rail and the first rail groove, in which the alignment groove is not formed, and having a convex portion at a position corresponding to the alignment groove.

7. The battery module of claim 6 , wherein the stopper further includes a lead that is extended from the leaf spring and exposed to the outside of the first battery cell and the second battery cell joined to alignment positions.