Pulsed charging and heating techniques for energy sources

A system configured to charge an energy source, comprising:

• a control system configured to:
• (a) monitor an impedance of the energy source, wherein a capacitance of the impedance includes a double layer sheet capacitance;
• (b) control a switch circuitry to apply a first charging signal at a preheating signal frequency based on the double layer sheet capacitance to an energy source until the energy source satisfies a transition condition, wherein the first charging signal comprises charge pulses, a duration of each charge pulse being less than ten milliseconds, wherein the preheating signal frequency is at a frequency that passes through the double layer sheet capacitance of the energy source, and wherein application of the first charging signal prevents or suppresses electrochemical charge transfer of a main storage reaction and one or more side reactions of the energy source;
• and
• (c) control the switch circuitry to apply a second charging signal to the energy source after the energy source satisfies the transition condition, wherein the second charging signal is a constant current charging signal.

A method of charging a plurality of energy sources within an energy storage system, wherein the energy storage system comprises a plurality of converter modules connected together in cascaded fashion, each converter module of the plurality of converter modules comprising an energy source and switch circuitry, wherein each converter module of the plurality of converter modules is independently controllable by a control system to output a module voltage, and wherein the energy storage system is configured to generate AC power with a superposition of module output voltages generated by the plurality of converter modules, the method comprising:

• monitoring an impedance for each of the plurality of energy sources, wherein a capacitance of the impedance includes a double layer sheet capacitance;
• applying, by switch circuitry of each module, a preheating signal at a preheating signal frequency based on the double layer sheet capacitance, wherein the preheating signal comprises a sequence of alternating charge and discharge energy pulses of equal duration to the energy source of each converter module to induce ohmic heating such that a temperature of the energy source of each converter module increases, wherein (i) the preheating signal is applied until the energy source reaches a first temperature, (ii) a frequency of the preheating signal is greater than one kilohertz, (iii) the preheating signal frequency is at a frequency that passes through the double layer sheet capacitance of the energy source, and (iv) application of the preheating signal occurs to prevent or suppress electrochemical charge transfer of a main storage reaction and one or more side reactions of the energy source of each converter module;
• and
• responsive to the energy source reaching the first temperature, applying, by the switch circuitry of each module, a charging signal to the energy source of each converter module.