Battery pack

1. A battery pack comprising:

a plurality of battery modules; and

a holding spacer which is placed between any two of the battery modules, wherein

the holding spacer has a spacer body;

in the holding spacer, a plurality of projections which protrude in a direction of placement of the plurality of battery modules and extend in a straight line shape in a vertical direction and which contact a side surface of at least one battery module and hold the battery module are formed, a cooling path through which a coolant is circulated is formed so as to extend in the vertical direction in a part where the projection is not formed, and a heat generating unit which heats the battery module is present within the spacer body; and

the spacer body is placed between one side of the heat generating unit and one of the two battery modules and between the other side of the heat generating unit and the other of the two battery modules.

2. The battery pack according to claim 1 , wherein

the heat generating unit is embedded in the holding spacer.

3. The battery pack according to claim 1 , wherein

a hollow section is formed in the holding spacer, and

the heat generating unit is inserted into the hollow section.

4. The battery pack according to claim 3 , wherein

the projection of the holding spacer is a hollow column-shaped projection which extends in a direction perpendicular to a direction of placement of the battery modules.

5. The battery pack according to claim 1 , wherein

the heat generating unit has a greater amount of heat generation at a peripheral section of the battery pack than at a center section of the battery pack.

6. The battery pack according to claim 1 , wherein

the battery module has a rectangular parallelepiped shape including a plurality of cells placed in a line.

7. The battery pack according to claim 6 , wherein

the battery module and the holding spacer are integrated by being sandwiched by end plates at both ends and restrained overall by a restraining unit.