Collision of gas molecules is the source of energy. We assemble a simple galvanic cell (analogous to the well-known battery). We place two electrodes with a potential difference in a NaCl solution. With a fixed load of the external circuit, we discharge the cell. Without breaking the external circuit, we cover the galvanic cell with a glass flask. In the mixture of atmospheric air located under the flask, we increase the percentage of carbon dioxide several times by introducing carbon dioxide under the flask. We record the restoration of the cell charge.