In principle it's possible.
The main obstacle is likely to be the battery management system. If it's fairly clever (ie. does cell balancing, etc) it would need programming with the characteristics of the new cells, and that is unlikely to be easy. Ask a Volvo specialist as a first step.

In the future a significant after-market battery 'repair' service will likely appear and they will probably have the tools, etc, to reprogram cars to run with their reconditioned batteries. Right now ... I doubt there's anyone can do it, but would love to be wrong.

 

damn that BMS !! I guess the whole thing is sort of wrapped up with CAN controls and other stuff - anything to make it difficult and anti-eco I guess.

 

There are drop in upgrades for the Prius. If there is enough demand it is more that possible.

 

There are drop in upgrades for the Prius.

Are they Toyota or aftermarket?

 

If I had to guess, the most UK candidate is Outlander. There are far more of them on the road than any other PHEV. But will "Outlander" owners care enough about an extra 5-10 miles EV range to drop £2000+ on a new pack?

A Prius with an out of warranty non-serviceable battery might be worth dropping $2,400 + labour (US price) to fix.

< shrug >

 

It's a bit academic, it's probably going to be corrosion and depreciation that stops anyone from doing this. When a car is 10 years old and only worth £4K, why would you spend more than the value of the car in replacing the battery cells? In reality I'd probably think twice about spending half the value of an old car on a repair The batteries are warrantied for 6-8 years and in reality you would expect them to last a lot longer. It's far more likely that someone who can't afford a new car would replace a failed battery with one from a scrapper.

Mass manufacturers are not interested in keeping their cars working for ever, they want to sell you a new car!

 

I think I'd like a bit more techy answers - I always assumed that essentially the only info the cars ECUs needed out of the battery pack was the current voltage - everything else re BMS balancing etc is sort of packaged into the battery module - in which case, as long as you can recreate those factors with an after-market setup you'd be ok - but I'll be honest, I'd completely forgotten the cost element !!

 

everything else re BMS balancing etc is sort of packaged into the battery module

Yes, but it probably 'knows' the capacity of the cells (Ah) as part of that. If you change to cells with, say, 50% more capacity you'll likely need to reprogram something in the BMS or it will get it's sums wrong. (You might end up with the same range.)

 

He’a a clever lad

 

now thats an answer to conjure with - to summarise - forget it Jeff !

 

EV Mods: Extending my extender + range test!

 

 

Didn't Mike Schooling try something like that and decide against offering it? As I recall he said the extra weight was not good for handling.....

 

If you replaced all the cells with newer ones bms might whinge and not report accurately but it should still continue working. Since charging mechanism relies on voltage rather thackeray supplied capacity the newer pack should charge to the original pack voltage.

- Leaf 30 kWh
Sent from mobile phone so please mind the typos

 

Since charging mechanism relies on voltage

It may for NiMH but for Li it's more complicated, in part because it's a more dangerous or at least less forgiving chemistry.
As replacement by owners is likely to be out of warranty and several years down the road, and expecting better range too, it's probable that the new cells will be a different chemistry as well as capacity (see the OP). So though a simple swap might 'work' it might not be safe or long lived.

DB's posts on the previous page are very informative.

 

Most Li-ion NMC based cells have a max stable charged voltage of 4.2V (some are 4.35V).

With li-ion NMC 4.2V cells, the charging mechanism is CC until desired voltage is achieved and then CV until amperage drops below certain level.

Newer chemistry doesn't charge basic charging mechanism.

If you are taking about chemistries like LTO or LiFePo4 then yes everything is different

- Leaf 30 kWh
Sent from mobile phone so please mind the typos

 

What would be great if cars were designed and built like the Fiat Centoventi Concept, so many good ideas on this concept including making the swapping/adding additional battery packs to the car look fairly simple (at 1 min 30) - maybe one day........

 

Most EV's don't charge Li-ion cells to 4.2 volts. 4.1 volts is typical, some go slightly higher but I'm not aware of any that go all the way to 4.2 volts. It puts too much strain on the cycle life for only an incremental range increase. (Cycle life is roughly halved by charging to 4.2 volts instead of 4.1 - not worth it for getting an extra 5% range or so!)

 

I was only referring to design voltage based on chemistries. Leaf only charges to 4.1V.

CC would take the cells to 4.1 and then CV cycle would run. If swapped entire pack the charging cycle will confine to function as such

- Leaf 30 kWh
Sent from mobile phone so please mind the typos

 

Most battery management systems dont care what capacity cells are installed, and they coulomb count - so given a few hundred driven miles after a capacity upgrade the stats reflect the increase.

 

Would you be willing to bet a few thousand pounds worth of new replacement battery pack on that though ?

I wouldn't, until someone else goes first.

 

Bear in mind that the BMS software may also have some "reality checks" built in, to limit charge time and total kWh discharge values etc., so might get confused and potentially shut down if cell capacity is increased, for safety reasons.