Tesla vehicles use approximately 8000 small cell batteries close to the size of a double A (AA) battery, only slightly larger with a length of 65 millimeters and a width of 18 millimeters. Tesla originally used this battery size because of its wide abundance but will be switching to a slightly larger size with a length of 70 mm and a width of 21 mm when their gigafactory is complete. Tesla claims that these new batteries will be the best and cheapest option in the world. Competitor manufacturers use different kinds of batteries than Tesla because of their belief in how the technology works and how efficient it can be