Battery pack and method for producing the battery pack

1. A battery pack comprising:

a battery stack including a plurality of battery cells stacked one on another;

a case member in which the battery stack is housed, the case member including:

a floor part located under the battery stack;

an end wall part located on one end in a stacking direction of the battery cells, the end wall part being continuously integrated with the floor part; and

a mounting-shape part located on an end opposite from the end wall part, the mounting-shape part being configured to mount a panel-shaped member; and

an end panel, which is the panel-shaped member, mounted in the mounting-shape part,

wherein the battery stack is retained in the case member while being held by compression between the end wall part and the end panel,

wherein the end panel is pressed against the mounting-shape part in a direction away from the end wall part by compression reaction force of the battery stack, so that the end panel is fixed in the mounting-shape part,

wherein the battery stack includes end plates located outside the battery cells arranged at both ends in the stacking direction,

the end plates include a first end plate located adjacent to the end panel,

the end panel is provided, in a lower part, with a first separation-restraining part configured to restrain the first end plate from moving upward and further coming off the case member, and

the first end plate is provided with a first hook part that engages the first separation-restraining part when the first end plate moves upward.

2. The battery pack according to claim 1 , wherein

the end plates include a second end plate located adjacent to the end wall part,

the end wall part is provided with a second separation-restraining part configured to restrain the second end plate from moving upward and further coming off the case member, and

the second end plate is provided with a second hook part that engages the second separation-restraining part when the second end plate moves upward.

3. The battery pack according to claim 2 , wherein

the second separation-restraining part is provided at a higher position than the first separation-restraining part, and

the first hook part has a longer length in the stacking direction of the battery stack than the second hook part.

4. A battery pack comprising:

a battery stack including a plurality of battery cells stacked one on another;

a case member in which the battery stack is housed, the case member including:

a floor part located under the battery stack;

an end wall part located on one end in a stacking direction of the battery cells, the end wall part being continuously integrated with the floor part; and

a mounting-shape part located on an end opposite from the end wall part, the mounting-shape part being configured to mount a panel-shaped member; and

an end panel, which is the panel-shaped member, mounted in the mounting-shape part,

wherein the battery stack is retained in the case member while being held by compression between the end wall part and the end panel,

wherein the end panel is pressed against the mounting-shape part in a direction away from the end wall part by compression reaction force of the battery stack, so that the end panel is fixed in the mounting-shape part,

wherein the battery stack includes end plates located outside the battery cells arranged at both ends in the stacking direction,

the case member includes a plurality of fixed parts arranged in the stacking direction of the battery stack and fixed to external fixing parts,

the battery pack has a gravity center that is located eccentrically, relative to a midpoint between two of the plurality of fixed parts, located at both ends in the stacking direction of the battery stack, toward an eccentric-side fixed part that is one of the two fixed parts located at both ends in the stacking direction,

one of the end wall part or the end panel, the one being located more distant from the eccentric-side fixed part in the stacking direction of the battery stack, is provided with a separation-restraining part configured to restrain the end plate adjacent to the one of the end wall part or the end panel from moving upward and further coming off the case member, and

the end plate adjacent to the one of the end wall part or the end panel is provided with a hook part that engages the separation-restraining part when the end plate moves upward.

5. A method for producing a battery pack, the battery pack comprising a battery stack including a plurality of battery cells and a case member in which the battery stack is housed, the case member including:

a floor part located under the battery stack;

an end wall part located on one end in a stacking direction of the battery cells, the end wall part being continuously integrated with the floor part; and

a mounting-shape part located on an end opposite from the end wall part, the mounting-shape part being configured to mount a panel-shaped member,

wherein the method comprises:

inserting the battery stack into the case member while compressing the battery stack in the stacking direction, and pressing one end of the battery stack in the stacking direction against the end wall part;

mounting an end panel, which is the panel-shaped member, in the mounting-shape part; and

releasing the battery stack from the compressing to allow an opposite end of the battery stack in the stacking direction to press against the end panel so that:

the battery stack is housed in the case member while being held by compression between the end wall part and the end panel, and

the end panel is pressed against the mounting-shape part in a direction away from the end wall part by compression reaction force of the battery stack, so that the end panel is fixed in the mounting-shape part,

wherein the battery stack includes end plates located outside the battery cells arranged at both ends in the stacking direction,

the end plates include a first end plate located adjacent to the end panel,

the end panel is provided, in a lower part, with a first separation-restraining part configured to restrain the first end plate from moving upward and further coming off the case member,

the first end plate is provided with a first hook part that engages the first separation-restraining part when the first end plate moves upward from a state where the battery stack is housed in the case member, and

the mounting of the end panel to the mounting-shape part is performed by moving down the end panel with the first separation-restraining part facing down, from above the mounting-shape part.

6. The method for producing a battery pack according to claim 5 , wherein

the end plates include a second end plate located adjacent to the end wall part,

the case member is provided, in the end wall part, with a second separation-restraining part configured to restrain the second end plate from moving upward and further coming off the case member, and

the second end plate is provided with a second hook part that engages the second separation-restraining part when the second end plate moves upward from a state where the battery stack is housed in the case member.

7. The method for producing a battery pack according to claim 6 , wherein

the second separation-restraining part of the case member is provided at a higher position than the first separation-restraining part, and

the first hook part of the first end plate has a longer length in the stacking direction of the battery stack than the second hook part of the second end plate.