BMW i3 info

BMW i3 info

It has a 125 kW BLDC electric motor (synchronous BLDC)


Max Torque:
"The BMW i3 eMachine is an Interior Permanent Magnet (IPM) machine with a heavily skewed rotor, and as such it has low saliency, meaning a low cogging torque.  However it has a high ratio between the d and q rotor axis inductance, meaning it can generate a high reluctance torque, and hence produces a high torque per amp output (but sacrifices maximum power capability to do so. At just about 2.5kW/kg, it's around 4x lower specific power output than the latest high speed eMachines.  As an IPM, you'll have to optimise the d/q axis current to find the angle at which the machine produces the highest torque/amp, unlike a Surface Permanent Magnet (SPM) machine that produces peak torque/Amp entirely within the q axis (when below it's base speed, ie not field weakened).  Some reverse engineering may be possible to pull that mapping from within the OEM controller....." - https://www.youtube.com/watch?v=LJtIS4KhvYM

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Tesla has an asynchrounous AC induction motor. AC induction motors are well known for enormous starting torque.

--------------- Battery sizes ------

Nissan Leaf charging problem in colder climates

Nissan does not have a thermal system handling the cold in their cars. Not even on the 2019 models. This is problematic in areas of cold weather when charging them. Charing cold batteries reduces the SEI layer.
Tesla on the other hand has a thermal system, heating pump, glycol between the batteries, warming the batteries when too cold for charging them (making it doable). (Source video below).

About the SEI layer
"The cell’s solid electrolyte interface (SEI) layer formation is a necessary part of the initialization process of the battery during the first charging cycles. The SEI layer protects the electrolyte material from further depletion and protects the charged anode from corrosion (the anode material reacts with the electrolyte material) [36]." - https://www.mdpi.com/1996-1073/12/5/946/pdf

Check out this video around  8:00 minutes in:




They also dont have any cooling for their batteries, so the batteries get hot when fast-charging..

Source: https://www.mestmotor.se/automotorsport/artiklar/nyheter/20180331/nya-siffror-nissan-leaf-tappar-en-hel-del-batterikapacitet-efter-bara-tva-ar/?fbclid=IwAR2rGbTldOTysAZb9jWXAqYkJgP9VtsoEe6xhM_VQ4USH9U2R1ZfB5JEr6A

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This is the same for Li-Ion as for LiFeP04.


Battleborn Battery CEO Interview! LiFePO4 Low-temp Charging, Storage, Longevity and so much more

---------------------- More about Nissan Leaf batteries and charging temperatures ----------

https://www.youtube.com/watch?v=WlxBOJrEKAo

2018 Leaf EV vs 2017 Bolt EV - Expected Li-Ion Battery Life