FRANKFURT, June 16 (Reuters) - Growth in Germany"s battery sector doubled to 35% last year led by demand for lithium-ion batteries for electric cars, data showed on Wednesday. "Sales especially of lithium-ion batteries have grown enormously," said Christian Eckert from electronic industry ZVEI, in a call with reporters. Turnover in the overall battery market in 2020 stood at 5.9 billion euros ($1.09 billion), with the lithium-ion segment seeing growth of 63% to 3 billion euros. Lithium-ion batteries are also used in medical equipment, smartphones, power tools and electric bikes. ZVEI said that most lithium-ion cells were imported from Asia into Germany. In German they are then turned into final battery products in a comprehensive production chain. Apart form domestic uses, they are also reexported to European and international markets. But imports of cells from European countries such as Poland were also growing, ZVEI noted. Demand for the second biggest segment, lead acid batteries, fell by 26% to 740 million euros. This came as combustion engine and fork lift truck manufacturing sank in the coronavirus crisis, which curbed industrial activity and demand. The car industry uses lead acid batteries for example in the supply of onboard systems while they are also used in emergency medical care and data centres. Volkswagen, the world"s second biggest carmaker, said on Tuesday it is vital to get a handle on raw materials access and costs for EV battery cells, which apart from lithium include graphite, cobalt and nickel, to exert more control over key components. It has mapped out plans to build six battery factories across Europe to 2030 together with partners. read more ($1 = 0.8246 euros)