A battery assembly, comprising: a first battery frame assembly having a first plastic frame member and a first thermally conductive plate; the first plastic frame member having a first rectangular ring-shaped peripheral wall and a first plurality of cross-members; the first rectangular ring-shaped peripheral wall having first, second, third and fourth wall portions (84, 86, 88, 90) defining a first central space, the first plurality of cross-members extending between the first and second wall portions (84, 86) and extending across the first central space, the first plurality of cross-members defining a first plurality of open spaces (160, 162, 164, 166, 168, 170) therebetween in the first central space; the first rectangular ring-shaped peripheral wall further having a first plurality of channels extending into the first wall portion proximate to the first plurality of open spaces (160, 162, 164, 166, 168, 170), and a second plurality of channels extending into the second wall portion proximate to the first plurality of open spaces (160, 162, 164, 166, 168, 170); the first thermally conductive plate having peripheral edges (180, 182, 184, 186) encapsulated within the first rectangular ring-shaped peripheral wall,; a first battery cell configured to contact the first thermally conductive plate; and a second battery frame assembly configured to be coupled to the first battery frame assembly such that the first battery cell is disposed between the first and second battery frame assemblies (20, 22), characterized in that the first thermally conductive plate further have exposed portions (190, 191, 192, 193, 194, 195) disposed in the first plurality of open spaces (160, 162, 164, 166, 168, 170) configured to contact air passing through the first plurality of channels and past the first thermally conductive plate and through the second plurality of channels to extract heat energy from the first thermally conductive plate. a first battery frame assembly having a first plastic frame member and a first thermally conductive plate; the first plastic frame member having a first rectangular ring-shaped peripheral wall and a first plurality of cross-members; the first rectangular ring-shaped peripheral wall having first, second, third and fourth wall portions (84, 86, 88, 90) defining a first central space, the first plurality of cross-members extending between the first and second wall portions (84, 86) and extending across the first central space, the first plurality of cross-members defining a first plurality of open spaces (160, 162, 164, 166, 168, 170) therebetween in the first central space; the first rectangular ring-shaped peripheral wall further having a first plurality of channels extending into the first wall portion proximate to the first plurality of open spaces (160, 162, 164, 166, 168, 170), and a second plurality of channels extending into the second wall portion proximate to the first plurality of open spaces (160, 162, 164, 166, 168, 170); the first thermally conductive plate having peripheral edges (180, 182, 184, 186) encapsulated within the first rectangular ring-shaped peripheral wall,; a first battery cell configured to contact the first thermally conductive plate; and a second battery frame assembly configured to be coupled to the first battery frame assembly such that the first battery cell is disposed between the first and second battery frame assemblies (20, 22),