Instead of using battery packs with hundreds of larger cells for its Roaster, Tesla deployed thousands of smaller lithium-ion cells for its inaugural model in 2006. This made the battery pack more expensive to produce, but this costlier architecture was considered safer and less prone to breakdowns. Straubel said. Since then, Tesla has cut the cost of its battery packs in half during the past seven years while avoiding any recalls or reports of breakdowns due to the packs.
Earlier this month, Tesla said it delivered its first quarterly profit during the first quarter, boosting its sales 83 percent from a year earlier to $562 million and selling 4,900 Model S EVs, which was more than what the Chevrolet Volt extended-range plug-in and Nissan Leaf battery-electric achieved.