Heated/cooled battery

A temperature controllable electric storage battery having monobloc construction and including thin, planar, heat exchangers placed throughout the battery between the electrode plates thereof. Preferably, the heat exchangers will comprise the intercell partitions of the battery container and the liquid passages therein will have an elongated cross section in a direction transverse the passage so as to provide a wide passage having the majority of the surface defining the passage lying in planes substantially parallel to the external face of the heat exchangers.