Lithium battery (Li-ion, Lithium Ion Battery): Li-ion battery has the advantages of light weight, large capacity, no memory effect, etc., so it has been widely used-many digital devices use lithium ion batteries as power sources, despite its price Relatively expensive. Lithium-ion battery has a high energy density, its capacity is 1.5 to 2 times that of a nickel-hydrogen battery of the same weight, and it has a very low self-discharge rate. In addition, lithium-ion batteries have almost no “memory effect” and do not contain toxic substances and other advantages are also important reasons for their wide application. In addition, please note that lithium batteries are generally marked with English 4.2V lithiumion battery (lithium battery) or 4.2V lithium secondary battery (lithium secondary battery), 4.2V lithiumion rechargeable battery (rechargeable battery), so users must be sure to purchase the battery Read the signs on the exterior of the battery block to prevent nickel-cadmium and nickel-hydrogen batteries from being mistaken for lithium batteries because the battery type is not clearly seen.