Battery pack with elastic frame

1. A battery module, comprising:

a plurality of unit battery cells stacked in a first direction;

a pair of end plates spaced from each other in the first direction and accommodating the unit battery cells therebetween, each of the end plates including a base plate and flanges bent from the base plate away from the unit battery cells;

an upper frame coupled to upper surfaces of the pair of end plates;

side supports coupled to side surfaces of the pair of end plates;

an elastic frame below the unit battery cells, the elastic frame extending in the first direction and the elastic frame having the capability of being elastically biased in a second direction that is perpendicular to the first direction; and

a lower frame below the battery cells, the lower frame being between the elastic frame and the unit battery cells, the lower frame including lower frame bent portions bent from the lower frame away from the unit battery cells;

wherein:

the elastic frame is coupled to the end plates with support protrusions including spacers thereon,

the spacers have a form of a washer, and the support protrusions are inserted through the spacers such that the spacers maintain a constant space between the lower frame and the elastic frame, and

an elastic force that the elastic frame exerts on the battery cells when the elastic frame is elastically biased in the second direction is changeable in response to a change in the thickness of the spacers.

2. The battery module as claimed in claim 1 , wherein the elastic frame has a plate spring structure.

3. The battery module as claimed in claim 1 , wherein the elastic frame is configured to be bent into a biased condition only after assembly of the battery module.

4. The battery module as claimed in claim 1 , wherein the elastic frame has a bent configuration for effecting a spring bias prior to assembly of the battery module.

5. The battery module as claimed in claim 1 , wherein the support protrusions are between the battery cells and ends of the elastic frame.

6. The battery module as claimed in claim 5 , wherein the spacer is between the battery cells and ends of the elastic frame.

7. The battery module as claimed in claim 6 , wherein the elastic frame has support openings, and the support protrusions are coupled to the support openings of the elastic frame.

8. The battery module as claimed in claim 7 , wherein the support protrusions are fixed protrusions extending from one of the end plates or the lower frame.

9. The battery module as claimed in claim 8 , wherein the elastic frame has an elastic portion and the elastic portion is narrower than the support portions.

10. The battery module as claimed in claim 8 , wherein the elastic frame has an elastic portion and the elastic portion is wider than the support portions.

11. The battery module as claimed in claim 5 , wherein the elastic frame includes:

an elastic portion,

support portions, and

support openings on the support portions.

12. The battery module as claimed in claim 11 , wherein the support openings are open ended support grooves.

13. The battery module as claimed in claim 11 , wherein the support openings are support through holes.

14. The battery module as claimed in claim 11 , wherein the support protrusions are disposed at ends of the lower frame, the support openings are disposed at ends of the elastic frame, and the support protrusions are coupled to the support openings.

15. A battery module, comprising:

a plurality of unit battery cells stacked in a first direction;

a pair of end plates spaced from each other in the first direction and accommodating the unit battery cells therebetween, each of the end plates including a base plate and flanges bent from the base plate away from the unit battery cells;

an upper frame coupled to upper surfaces of the pair of end plates;

side supports coupled to side surfaces of the pair of end plates;

an elastic frame below the unit battery cells, the elastic frame extending in the first direction and having an arc shape that is arched toward the battery cells in a second direction that is perpendicular to the first direction; and

a lower frame below the battery cells, the lower frame being between the elastic frame and the unit battery cells, the lower frame including lower frame bent portions bent from the lower frame away from the unit battery cells;

wherein:

the elastic frame is coupled to the end plates with support protrusions including spacers thereon,

the spacers have a form of a washer, and the support protrusions are inserted through the spacers such that the spacers maintain a constant space between the lower frame and the elastic frame, and

an elastic force that the elastic frame exerts on the battery cells is changeable in response to a change in the thickness of the spacers.

16. A battery module, comprising:

a plurality of unit battery cells stacked in a first direction;

a pair of end plates spaced from each other in the first direction and accommodating the unit battery cells therebetween, each of the end plates including a base plate and flanges bent from the base plate away from the unit battery cells;

an upper frame coupled to upper surfaces of the pair of end plates;

side supports coupled to side surfaces of the pair of end plates;

an elastic frame below the unit battery cells for supporting the unit battery cells, the elastic frame extending in the first direction, the elastic frame also including end regions, each end region being adjacent to one of the end plates, and a middle region between the end regions, the middle region extending in a second direction that is perpendicular to the first direction and toward the unit battery cells so as to be disposed upwardly and inwardly relative to the end regions, and

a lower frame below the battery cells, the lower frame being between the elastic frame and the unit battery cells, the lower frame including lower frame bent portions bent from the lower frame away from the unit battery cells;

wherein:

the elastic frame is coupled to the end plates with support protrusions including spacers thereon,

the spacers have a form of a washer, and the support protrusions are inserted through the spacers such that the spacers maintain a constant space between the lower frame and the elastic frame, and

an elastic force that the elastic frame exerts on the battery cells is changeable in response to a change in the thickness of the spacers.