Renewable energy sources (RESs) represent a striking energy supply that can help reducing the environmental impact of electricity production. However, some of them (e.g. solar or wind) are intermittent by nature. To overcome this relevant issue, energy storage is an efficient way to maintain a constant electric supply. Batteries used as electrochemical storage represent one of the best solutions. Solid-state-batteries (SSBs) are devices relying on solid electrolytes to store energy. Their integration to systems based on RESs represent an effective way to overcome their intermittence. This solution is progressively replacing the commonly used liquid electrolytes since they suffer from low thermal stability being volatile and may cause serious safety issues.