MikeB
Posts: 4
Joined: Fri Mar 02, 2018 5:43 pm

Would the i3 benefit from supercapacitors

Fri Mar 02, 2018 7:21 pm

My i3 is easily the best and most fun car I’ve ever owned.
It is a little rocket ship that seems capable of reaching orbital velocity.
I like the single-pedal driving a lot. It is simply safer and less stressful to drive this way.
Although, there is always room for improvement.
When the battery is full or it is cold out the regenerative braking is greatly reduced and I have to modify my style of driving.
Could supercapacitors be used to correct this? They are not affected by ambient temperature.
The implementation would be something like this:
1. The supercapacitors would not charge up during charging.
2. The power from regenerative braking would be directed to the supercapacitors first and only to the battery if the caps are full.
3. The motor would always deplete the caps first before pulling power from the HV battery.

Since the discharge rate of supercapacitors is far higher than lithium-ion batteries, it should be possible to supply the motor with greater power for short periods of acceleration.

MikeB, 3/2/2018, owner of 2015 i3 BEV

theothertom
Posts: 364
Joined: Mon Mar 20, 2017 6:08 am
Location: South Carolina

Re: Would the i3 benefit from supercapacitors

Sat Mar 03, 2018 6:20 am

MikeB wrote: When the battery is full or it is cold out the regenerative braking is greatly reduced and I have to modify my style of driving.
I haven't found that regenerative braking is reduced when it's cold out. It is reduced when the battery is full but that doesn't last long :)

My understanding of super capacitors is that they charge and discharge quickly, but have a relatively low energy density. That means you'll need a lot of them to make a difference. So yes, super capacitors would help if you had a lot of them. I'm sure someone who has a better understanding of super capacitors will chime in.

Gridvantage
Posts: 11
Joined: Thu Aug 21, 2014 6:28 pm

Re: Would the i3 benefit from supercapacitors

Sun Apr 08, 2018 9:22 am

In addition to having low energy density, which means sizeable space would be needed, supercapacitors have a diffferent voltage curve than batteries, which means that you would need an additional power conversion unit, so more electronics, more space, more costs, more potential problems.... In my opinion, it's not worth the few times the battery regen gets maxed out.

Return to “Suggestions for BMW”