BMW vs Tesla (Battery Weight)

[chadever]

The new 2017 BMW i3 will be using four M8994 E2 Samsung modules (8.38 kWh each). These modules, according to Samsung, will be > 60kg (>132 pounds) each. Assuming that BMW's modules will weigh 127 pounds (quite favorable), they would be 15.14 pounds per kWh.

http://www.samsungsdi.co.kr/upload/ess_brochure/Samsung SDI ESS brochure.pdf

Unfortunately Tesla and Panasonic do not have specs out on how much each module weighs... but you can buy them used on eBay! According to eBay sellers, a 5.3 kWh from an 85D weighs roughly 55 pounds. Assuming that eBay sellers are correct (they are shipping these things), the Tesla modules are 10.37 pounds per kWh.

4 Tesla Model S battery modules, 24V, 21.2kWh, 1776 Panasonic 18650 cells

BMW 15.14 lbs/kWh
Tesla 10.37 lbs/kWh

Tesla uses cylindrical cells (round, but light) while BMW uses prismatic cells (thin, but heavy). BMW batteries weigh 508 pounds while the range extender weighs 265 pounds. Why commit 773 pounds when an almost identical amount of weight could be used towards 75kWh of cylindrical cells/modules? Why does BMW, the people that are in love with carbon fiber and everything light weight, use such a heavy, inferior battery technology in their light weight cars?

 

[chadever]

Also, using Samsung and eBayer's dimensions, it seems that Tesla batteries are also far better in kWh per cubic inches

Tesla 168 cui/kWh
BMW 254 cui/kWh

 

[Kandiru]

Building an EV with a skeleton crew and limited funding leads to predictable results. The humble Leaf is at least priced accordingly.