A method of making a bipolar battery assembly comprising the steps of: providing a dielectric substrate having a first surface and an opposing second surface; forming a plurality of openings in the substrate; filling the plurality of openings with at least one electrically conductive material admixture that undergoes a phase transformation at a temperature that is below the thermal degradation temperature of the substrate so that at an operating temperature of the battery assembly that is below the phase transformation temperature the dielectric substrate has an electrically conductive path via the material admixture between the first surface and the second surface of the substrate, and at a temperature that is above the phase transformation temperature, the electrically conductive material admixture undergoes a phase transformation that disables electrical conductivity via the electrically conductive path wherein the at least one electrically conductive material admixture comprises a solder material comprising a mixture of any two or more of lead, tin, nickel, zinc, lithium, antimony, copper, bismuth, indium and silver, wherein the substrate is formed from a material capable of withstanding temperatures that exceed the melting points of the electrically conductive materials; covering the substrate with a first current collector sheet that will function as a negative current collector in a first cell of the battery on the first surface of the substrate, and a second current collector sheet that will function as a positive current collector in a second cell of the battery on the second surface of the substrate, the first current collector sheet and the second current collector sheet being disposed so that the at least one electrically conductive material and the substrate is sandwiched therebetween; positioning a first non-conductive pasting frame member on the first current collector sheet in planar contact with an edge of the substrate thereby creating a leakproof seal along the exterior of the battery; and positioning a second non-conductive pasting frame member on the second current collector sheet in planar contact with an edge of the substrate. providing a dielectric substrate having a first surface and an opposing second surface; forming a plurality of openings in the substrate; filling the plurality of openings with at least one electrically conductive material admixture that undergoes a phase transformation at a temperature that is below the thermal degradation temperature of the substrate so that at an operating temperature of the battery assembly that is below the phase transformation temperature the dielectric substrate has an electrically conductive path via the material admixture between the first surface and the second surface of the substrate, and at a temperature that is above the phase transformation temperature, the electrically conductive material admixture undergoes a phase transformation that disables electrical conductivity via the electrically conductive path wherein the at least one electrically conductive material admixture comprises a solder material comprising a mixture of any two or more of lead, tin, nickel, zinc, lithium, antimony, copper, bismuth, indium and silver, wherein the substrate is formed from a material capable of withstanding temperatures that exceed the melting points of the electrically conductive materials; covering the substrate with a first current collector sheet that will function as a negative current collector in a first cell of the battery on the first surface of the substrate, and a second current collector sheet that will function as a positive current collector in a second cell of the battery on the second surface of the substrate, the first current collector sheet and the second current collector sheet being disposed so that the at least one electrically conductive material and the substrate is sandwiched therebetween; positioning a first non-conductive pasting frame member on the first current collector sheet in planar contact with an edge of the substrate thereby creating a leakproof seal along the exterior of the battery; and positioning a second non-conductive pasting frame member on the second current collector sheet in planar contact with an edge of the substrate.