A method for filling foil container electrochemical cells with fluid electrolyte and an integral structure for such foil container cells which permits such method. The second die pad is bent in a manner facilitating the formation of a cavity therein. Since the amplifiers can be biased at ground potential, no significant DC voltage exists across the load and the need for DC coupling capacitors is eliminated. Therefore, an increased offset effect for the pulsation of noise is obtained, which maximizes a noise attenuation effect. Furthermore, by measuring the same ratio when a fixed resistor is substituted for the thermistor, a cell constant can be derived.