Onboard battery

An onboard battery comprising:

• battery modules in each of which a battery cell is disposed;
• a housing case that houses the battery modules;
• and
• an air intake duct configured to send cooling air into the battery modules, wherein
• of the battery modules, at least two are disposed apart from each other in a vertical direction and at least two are disposed apart from each other in a front-rear direction,
• cooling air is taken into the battery modules from rear via the air intake duct,
• cooling air taken into the battery modules is emitted to an internal space of the housing case,
• a rear portion of the housing case is provided with at least one exhaust hole configured to let out the cooling air emitted from the battery modules to the internal space of the housing case, and
• of emission flows of the cooling air emitted from the battery modules to the internal space of the housing case, the emission flow of the cooling air emitted from at least one of the battery modules which is disposed most forward is the largest.