Battery pack manufacturing method

1. A battery pack manufacturing method comprising:

(a) stacking battery cells to form a cell stack;

(b) coupling the cell stack and a U-frame to each other;

(c) measuring a volume of a space bounded in a height dimension by a lower surface of the cell stack and a flat plate coupled to free ends of opposing sidewalls of the U-frame, the space bounded in a width dimension by the opposing sidewalls of the U-frame, and the space bounded in a length dimension by end plates coupled to opposing ends of the U-frame in the length dimension; and

(d) applying an amount of a polymer resin to fill the volume measured in step (c).

2. The battery pack manufacturing method according to claim 1 , wherein step (d) comprises applying the polymer resin to an inner surface of the flat plate.

3. The battery pack manufacturing method according to claim 1 , wherein step (c) comprises determining a contour of the lower surface of the cell stack using a fluoroscopic imaging apparatus.

4. The battery pack manufacturing method according to claim 3 , wherein step (c) comprises:

(i) capturing positions of a maximum protrusion and a minimum protrusion of the lower surface of the cell stack; and

(ii) calculating a protruding length tolerance between the maximum protrusion and the minimum protrusion.

5. The battery pack manufacturing method according to claim 1 , wherein step (c) comprises measuring a length from a determined contour of the lower surface of the cell stack to the free ends of the U-frame.

6. The battery pack manufacturing method according to claim 1 , wherein step (c) comprises:

(i) measuring a plurality of lengths between the flat plate and the lower surface of the cell stack to calculate a correction length (Z′); and

(ii) multiplying the correction length (Z′) by an area of the lower surface of the cell stack.

7. The battery pack manufacturing method according to claim 6 , wherein the correction length (Z′) is an average of a maximum value and a minimum value calculated by using a tolerance range based on the plurality of lengths between the flat plate and the lower surface of the cell stack, defined by the following formula:

Z′ =( M 0+ M 1− M 2)

wherein M 0 indicates a distance between a maximum protrusion and a minimum protrusion of the lower surface of the cell stack, M 1 indicates a length from the maximum protrusion of the lower surface of the cell stack to the free ends of the opposing sidewalls of the U-frame, and M 2 indicates a dimension between a portion of the flat plate opposed to the lower surface of the cell stack, to which the polymer resin is applied, and a portion of the flat plate to which the free ends of the U-frame are coupled,

wherein, when M 0 and M 1 have a minimum tolerance according to the tolerance range and M 2 has a maximum tolerance according to the tolerance range, Z′ indicates the minimum value, and

wherein, when M 0 and M 1 have a maximum tolerance according to the tolerance range and M 2 has a minimum tolerance according to the tolerance range, Z′ indicates the maximum value.

8. The battery pack manufacturing method according to claim 1 , wherein step (b) comprises:

(i) coupling the U-frame and the cell stack to each other such that the U-frame wraps around an upper surface and a side surface of the cell stack, and

(ii) disposing the cell stack coupled to the U-frame such that a base of the U-frame faces a ground surface.

9. The battery pack manufacturing method according to claim 1 , further comprising (e) welding the U-frame and the flat plate to each other.

10. The battery pack manufacturing method according to claim 9 , wherein the welding is performed with the flat plate disposed in contact with the free ends of the U-frame by pushing the flat plate downwards.

11. The battery pack manufacturing method according to claim 10 , wherein the pushing of the flat plate downwards comprises compressing the U-frame in a direction in which a first sidewall and a second sidewall of the opposing sidewalls of the U-frame face each other.

12. The battery pack manufacturing method according to claim 1 , wherein the polymer resin is a thermally conductive polymer resin.

13. The battery pack manufacturing method according to claim 1 , wherein step (c) comprises determining a contour of the lower surface of the cell stack.