How is a large Li-Ion battery pack, such as in a car, manufactured? What makes it difficult to produce, if anything?
This question is born from the high cost of Tesla Model S, which is around $70k. In contrast, the average 4-door car is more like $20 or $30k despite having an internal combustion engine.
I don't understand that. I would have thought that a big battery, which has no moving parts, would be much much cheaper than a 4-cylinder engine.
So what's the expense in making a large Li-Ion battery? Is lithium much more expensive than steel? Are there major (expensive) safety precautions in manufacture? Is the battery pack very intricately "woven" with cells? Something else?
Best Answer
Like horta said, battery grade lithium (~$5.00 USD per pound) is quite expensive compared to steel (depends, it can be less than $1 USD per pound) or aluminum (also usually less than $1 USD per pound) used in an engine block.
Lithium likes to react with the atmosphere, forming lithia/lithium oxide. Refined lithium or just lithium in general will likely require special handling, also increasing costs. There are quite a few regulations regarding the shipment of lithium.
Large Li-ion batteries or cells, especially in cars, can pose a safety risk when they are punctured or exposed to atmospheric oxygen. Just google, "exploding li-ion battery". Having smaller/individual cells like 18650 batteries could help minimize the amount of lithium that is exposed when the is battery damaged. However, having a greater number of smaller cells can increase the cost of manufacturing as they could easily be more sophisticated (cooling, wiring, assembly of cells etc...)
In conclusion:
Main costs of large Li-ion batteries: