Power bank

The utility model discloses a charge pal which comprises a shell and a battery arranged in the shell, and further comprises a self-moisture-absorption hydrogel layer which is arranged in parallel with the battery and can be in contact with external air, and the self-moisture-absorption hydrogel layer and the battery are in heat conduction connection and waterproof isolation through a partition plate part. When the battery works, heat generated by the battery can be transmitted to the self-moisture-absorption hydrogel layer through the partition plate part, so that the self-moisture-absorption hydrogel layer can absorb the heat and exchange the heat into the air through internal water evaporation, and due to the fact that the heat exchange efficiency is higher compared with that of air cooling through water vapor evaporation, it is guaranteed that the temperature of the power bank is not too high. And when the power bank is not used for charging, the self-moisture-absorption hydrogel layer is cooled and then g