Battery pack

1. A battery pack, comprising:

a plurality of battery cells arranged in parallel in a length direction, each of the battery cells including ends with electrode regions;

a holder case including an inner space accommodating the battery cells;

a protection circuit module on an outer surface of the holder case and in an outer space of the holder case; and

a temperature sensor extending from a region facing the holder case, wherein:

an insertion area is at a location of the holder case which corresponds to the temperature sensor and wherein the insertion area includes a removed part of the holder case, the temperature sensor passing through the insertion area of the holder case and between the holder case and an outer surface of at least one of the battery cells to contact the outer surface of the at least one of the battery cells,

the temperature sensor extends from the outer surface of the at least one of the battery cell in the inner space of the holder case to the protection circuit module in the outer space of the holder case through the insertion area of the holder case, and

an interval between the holder case and the outer surface of the at least one of the battery cells where the temperature sensor is located varies.

2. The battery pack as claimed in claim 1 , wherein an interval between the holder case and an outer surface of at least one of the battery cells adjacent to the insertion area is greater than the interval between the holder case and the outer surface of the at least one of the battery cells where an end of the temperature sensor is located.

3. The battery pack as claimed in claim 1 , wherein the temperature sensor is a flexible printed circuit board (FPCB) type.

4. The battery pack as claimed in claim 1 , wherein:

the holder case is on side surfaces of the battery cells and extends to circumferences of the electrode regions, and

the holder case is bent from the side surfaces to the electrode regions at the ends of the battery cells.

5. The battery pack as claimed in claim 4 , wherein:

the holder case on the circumferences of the electrode regions includes an exposing portion corresponding to the removed part of the holder case, and

the removed part of the holder case corresponds to the temperature sensor.

6. The battery pack as claimed in claim 5 , wherein:

the exposing portion is covered by a hinge portion, and

the hinge portion includes a hole portion that opens a region where the temperature sensor contacts the one least one of the battery cells.

7. The battery pack as claimed in claim 1 , further comprising:

a connection tab adjacent the electrode regions of the battery cells, to electrically connect the battery cells to each other; and

an insulation area over the connection tab.

8. A battery pack, comprising:

a plurality of battery cells;

a case for the battery cells; and

a temperature sensor extending through a hole in the case at an outer surface of at least one of the battery cells to contact the outer surface of the at least one of the battery cells, wherein a portion of the temperature sensor extending through the hole is between the case and the outer surface of the at least one of the battery cells and has a shape;

wherein an interval between the case and the outer surface of the at least one of the battery cells where the temperature sensor is located varies.

9. The battery pack as claimed in claim 8 , wherein the portion of the temperature sensor extending through the hole conforms to a shape of the outer surface of the at least one of the battery cells.

10. The battery pack as claimed in claim 9 , wherein the shape of the outer surface of the at least one of the battery cells is curved.

11. The battery pack as claimed in claim 8 , further comprising a protection circuit adjacent to the battery cells, wherein the temperature sensor extends from the protection circuit.