Abstract: The present invention discloses a lithium-ion battery protector, comprising a broken-circuit protection switch arranged in a charging loop of a lithium-ion battery pack, wherein the broken-circuit protection switch is adapted to carry out the switching-on or switching-off of the charging loop of the lithium-ion battery pack via the shape change of a shape memory alloy therein at different temperatures. The lithium-ion battery protector uses the memorability, interference resistance, high voltage resistance and passive over-current capacity of the shape memory alloy.