A battery case for housing a battery with a plurality of electrochemical cells and at least one electronic component, the battery case comprising: a plurality of interconnected cell housings made of at least one heat conductive material selected from the group consisting of metal, composite, and polymer, wherein the plurality of interconnected cell housings each define an internal space sized to accommodate one of the electrochemical cells, and include an internal surface that is contoured to a shape of the one of the electrochemical cells to be housed by the cell housing, wherein the internal surface of each cell housing is cylindrical to match the electrochemical cells having a substantially cylindrical shape, and each of the cell housings completely encloses an outer circumferential surface of the electrochemical cell to be accommodated by the cell housing, and an external surface that is in contact with another external surface of at least one other cell housing, wherein the external surface of each cell housing also is contoured to the shape of the electrochemical cell to be housed therein, wherein the external surfaces of the cell housings define a plurality of interior volumes that are external to each of the cell housings and internal to an outer periphery of the battery case, and wherein at least one of the interior volumes houses a heat conductive filler material selected from the group consisting of metal, composite, and polymer; wherein the outer periphery of the battery case includes non-planar sides defined by the external surfaces of the cell housings; and at least one electronic component housing inside the battery case that accommodates the at least one electronic component, characterized in that the electronic component housing being positioned such that it is enclosed on all longitudinal sides by the plurality of interconnected cell housings, and an accessible interface for plugging in a device provided either by the electronic component housing or through a longitudinal side of the battery case. a plurality of interconnected cell housings made of at least one heat conductive material selected from the group consisting of metal, composite, and polymer, wherein the plurality of interconnected cell housings each define an internal space sized to accommodate one of the electrochemical cells, and include an internal surface that is contoured to a shape of the one of the electrochemical cells to be housed by the cell housing, wherein the internal surface of each cell housing is cylindrical to match the electrochemical cells having a substantially cylindrical shape, and each of the cell housings completely encloses an outer circumferential surface of the electrochemical cell to be accommodated by the cell housing, and an external surface that is in contact with another external surface of at least one other cell housing, wherein the external surface of each cell housing also is contoured to the shape of the electrochemical cell to be housed therein, wherein the external surfaces of the cell housings define a plurality of interior volumes that are external to each of the cell housings and internal to an outer periphery of the battery case, and wherein at least one of the interior volumes houses a heat conductive filler material selected from the group consisting of metal, composite, and polymer; wherein the outer periphery of the battery case includes non-planar sides defined by the external surfaces of the cell housings; and an internal surface that is contoured to a shape of the one of the electrochemical cells to be housed by the cell housing, wherein the internal surface of each cell housing is cylindrical to match the electrochemical cells having a substantially cylindrical shape, and each of the cell housings completely encloses an outer circumferential surface of the electrochemical cell to be accommodated by the cell housing, and an external surface that is in contact with another external surface of at least one other cell housing, wherein the external surface of each cell housing also is contoured to the shape of the electrochemical cell to be housed therein, wherein the external surfaces of the cell housings define a plurality of interior volumes that are external to each of the cell housings and internal to an outer periphery of the battery case, and wherein at least one of the interior volumes houses a heat conductive filler material selected from the group consisting of metal, composite, and polymer; wherein the outer periphery of the battery case includes non-planar sides defined by the external surfaces of the cell housings; and at least one electronic component housing inside the battery case that accommodates the at least one electronic component, characterized in that the electronic component housing being positioned such that it is enclosed on all longitudinal sides by the plurality of interconnected cell housings, and an accessible interface for plugging in a device provided either by the electronic component housing or through a longitudinal side of the battery case.