Trough battery spaces between the plates (the troughs) were filled with dilute sulfuric acid. So long as the box was not knocked about, there was no risk of electrolyte spillage. Trough battery The trough battery was a variant of Alessandro Volta's Voltaic Pile and was invented by William Cruickshank c. 1800. Volta's battery consisted of brine-soaked pieces of cloth sandwiched between zinc and copper discs, piled in a stack. This resulted in electrolyte leakage as the weight of the discs squeezed the electrolyte out of the cloth. Cruickshank solved this problem by laying the battery on its side in a rectangular box.
Plug-in electric vehicles in the United States will be plug-in hybrids or full battery electrics by 2030. The U.S. Energy Information Administration (EIA) in its 2017 Annual Energy Outlook 2017 projected that all-electric vehicles sales in the United States will increase from less than 1% in 2016 to 6% in 2040 of total light-duty vehicles sold in the country, and plug-in hybrid electric vehicle sales will increase from less than 1% to 4% over the same period. According to the EIA projected sales of light-duty battery electric, plug-in hybrid electric, and hydrogen fuel cell vehicles will reach 1.5 million in 2025, about 9% of projected total sales