The EV fact thread

[BTB 500]

This explains the battery sizes for the IONIQ 5 of my generation (I think that from MY 2025 the capacity has increased):

Apparently the current models (IONIQ 5 84 kWh RWD, IONIQ 5 N) also use only two parallel strings of cells:

True, the car was first registered in Sep 2021 and the fault occurred in Jan 2025. The car covered 8,000 miles.

Needing a two month repair after covering just 8k miles would be pretty unlikely with any ICE Mercedes, IMHO. From the survey you quoted:

Overall, most faulty Mercedes models were fixed in less than a week

Interesting that an EV-only manufacturer (Polestar) was placed lower than Mercedes.

 

[BTB 500]

Indeed but it's got to be the way forward for all battery packs, if EVs are to be realistic. That all said ICE were repairable until recently. Engine rebuilds were common, now if they do go wrong it's a full replacement. Luckily they don't often go bang these days and I'd imagine the same will be the case for EV batteries as the design/manufacture matures?

There are many ICE engine problems that can be fixed without a total rebuild or replacement though. Catastrophic failures are even more rare.

EV battery packs are vulnerable because they rely on large numbers of mass-produced Li Ion cells, which really aren't very robust. It's of note that Toyota/Lexus stuck with NiMH packs for their hybrids until very recently, and those are legendary for their reliability/longevity. They just don't have the energy density of Li Ion, so are bigger & heavier for any given capacity. Swings & roundabouts.

It's likely that a new battery chemistry will appear at some point (there's always something 'just over the horizon') and revolutionise EVs.

 

[markjay]

..Needing a two month repair after covering just 8k miles would be pretty unlikely with any ICE Mercedes, IMHO.

Again, I agree. One week for diagnostics and three weeks in transit is insane.

...Interesting that an EV-only manufacturer (Polestar Tesla) was placed lower higher than Mercedes.

FTFY - this door swings both ways, you know!

 

[BTB 500]

Is there a confusion of terminology regarding cells and modules? Modules contain a number of cells...
From the website I linked above..
"Each battery ‘cell-module’ contains several individual “cells” inside of it, these are welded together and contained within a continuous plastic or metal casing, these “cells” are integral parts of the ‘cell-module’ & cannot be disconnected from each-other or removed without causing damage to the module. Individual ‘cells’ cannot be tested either outside of a Lab as there is no physical access to them."

You can't manufacture a battery from hundreds (or more typically, thousands) of individual cells all directly connected. They're assembled in manageable blocks (modules), which are then connected together to form the pack. Once you remove the pack from a car and take it apart (not trivial) modules can be swapped out relatively easily, but taking a module apart and replacing individual failed cells within it wouldn't be cost-effective.

 

[markjay]

Interestingly, of the top five brands, four are Japanese.

In fact, if you lumped Mini with BMW, and Lexus with Toyota, you'll get the top three spots taken by Japanese marques.

This hasn't really changed since the nineties.

 

[Steveml63]

There are many ICE engine problems that can be fixed without a total rebuild or replacement though. Catastrophic failures are even more rare.

EV battery packs are vulnerable because they rely on large numbers of mass-produced Li Ion cells, which really aren't very robust. It's of note that Toyota/Lexus stuck with NiMH packs for their hybrids until very recently, and those are legendary for their reliability/longevity. They just don't have the energy density of Li Ion, so are bigger & heavier for any given capacity. Swings & roundabouts.

It's likely that a new battery chemistry will appear at some point (there's always something 'just over the horizon') and revolutionise EVs.

There is already a new battery chemistry in common use by Tesla and many other EV manufacturers - LFP (Lithium Iron Phosphate).
This has two big advantages over existing technology used and one disadvantage!
The two advantages - they don’t catch fire and you can (and actually should regularly) charge to 100% (rather than the 80-90% recommended on the traditional batteries).
The one disadvantage is the charge density for a given pack weight and size is lower - so lower range for a given pack size.

 

[ALFAitalia]

This explains the battery sizes for the IONIQ 5 of my generation (I think that from MY 2025 the capacity has increased):

True, the car was first registered in Sep 2021 and the fault occurred in Jan 2025. The car covered 8,000 miles.

The car was faultless for the first 3 years. My evaluation of MB reliability during the first few years is based on reliability surveys, e.g.:

What Car? Reliability Survey: Most and least reliable car brands

In our annual Reliability Survey, we ask readers to rate the dependability of cars aged up to five years old. Here we rank the most and least reliable car manufacturers in the UK

www.whatcar.com

Regarding the 'two months off the road', I fully agree, and I said as much in my previous post. Setting aside the bizarre logistics of having a car two weeks in transit in either direction, none of it would have been necessary if the dealership was able to swap a battery module without having to ship the car to Hyundai UK to have the entire battery pack replaced.

MG at the bottom.... what a surprise...not. I have a mate who works at the new MG centre in Bognor.... some of the build quality horror stories he tells me! Mind you...it should be obvious looking at the lack quality and poor fit of the bits you can see that the bits you can't see would be worse. No offence meant to those on here that I know own them. No doubt they are fault free! Apparently though the new models will be a big leap forward on quality.

 

[SmartAmg]

MG at the bottom.... what a surprise...not. I have a mate who works at the new MG centre in Bognor.... some of the build quality horror stories he tells me! Mind you...it should be obvious looking at the lack quality and poor fit of the bits you can see that the bits you can't see would be worse. No offence meant to those on here that I know own them. No doubt they are fault free! Apparently though the new models will be a big leap forward on quality.

Agree, not really a suprise that MG are bottom. After some of the things I've read. But if you go on any car forum there are far more moaning about the car, than praising it. But mine after 7 months, is
(So far, fault free) and to be fair, the fit and finish really is pretty good. And that's all I can go off, my own experiences with the car.

 

[BTB 500]

There is already a new battery chemistry in common use by Tesla and many other EV manufacturers - LFP (Lithium Iron Phosphate).
This has two big advantages over existing technology used and one disadvantage!
The two advantages - they don’t catch fire and you can (and actually should regularly) charge to 100% (rather than the 80-90% recommended on the traditional batteries).
The one disadvantage is the charge density for a given pack weight and size is lower - so lower range for a given pack size.

LiFePO4 isn't new at all - these cells have been commercially available for 15+ years. They were originally referred to as 'A123' as that was the name of the (Chinese) company that first made them. They are certainly safer and more robust than Li Ion but there are some other drawbacks - the cell voltage is lower (3.2v nominal rather than 3.7v), and they can't be charged as fast. So not the game changer we need for EVs, IMHO.

 

[BTB 500]

LiFePO4 isn't new at all

I just checked the manual for an old battery charger I still have - that was upgraded at the end of 2006 to support LiFePO4 (LFP) ... so these cells actually pre-date (mass market) EVs!

 

[Bobby Dazzler]

Needing a two month repair after covering just 8k miles would be pretty unlikely with any ICE Mercedes, IMHO. From the survey you quoted:

Two month repairs aren’t unusual these days, regardless of brand or drivetrain, simply because of availability of parts. In the space of two years I’ve had the same car at the ICE Mercedes main dealer for more than 3 months and again for more than 5 months, whilst waiting for parts under warranty. Neither relating to drivetrain, but off the road all the same.

“Overall, most faulty Mercedes models were fixed in less than a week”

I haven’t looked at the data so I can’t say for sure, but I dare say that the same could be said about Hyundai. Both brands will have outliers.

 

[markjay]

I just checked the manual for an old battery charger I still have - that was upgraded at the end of 2006 to support LiFePO4 (LFP) ... so these cells actually pre-date (mass market) EVs!

As do Li-ion batteries... from memory, Li-ion started replacing NiCad around the turn of the Century.... this is in spite of NiCad being less prone to catching fire as a result of physical damage, and being overall a safer product.

I think that the main reason that EV battery tech is currently based on Li-ion, is that two decades ago one Elon Musk decided to rig together a pile of laptop batteries and cram them into a Lotus Elise after stripping away the original engine and transmission, and the rest is history.

 

[Steveml63]

LiFePO4 isn't new at all - these cells have been commercially available for 15+ years. They were originally referred to as 'A123' as that was the name of the (Chinese) company that first made them. They are certainly safer and more robust than Li Ion but there are some other drawbacks - the cell voltage is lower (3.2v nominal rather than 3.7v), and they can't be charged as fast. So not the game changer we need for EVs, IMHO.

By “new” I meant in general use in EVs - rather than being used in household & industrial electrical items.

 

[BTB 500]

Two month repairs aren’t unusual these days, regardless of brand or drivetrain, simply because of availability of parts.

It's certainly possible but I would still say unusual in a car that's under 3.5 years old and has only done 8k miles. Any kind of major failure at that age would be pretty rare to start with, and parts are normally available for current mass-market cars. Of course not necessarily for niche models e.g. the chap on here whose new EQC needed a replacement battery after 1000 miles - he was still waiting after 3 months, and we never did hear what happened in the end.

 

[Bobby Dazzler]

It's certainly possible but I would still say unusual in a car that's under 3.5 years old and has only done 8k miles. Any kind of major failure at that age would be pretty rare to start with, and parts are normally available for current mass-market cars. Of course not necessarily for niche models e.g. the chap on here whose new EQC needed a replacement battery after 1000 miles - he was still waiting after 3 months, and we never did hear what happened in the end.

I agree it is unusual. I’d say it’s unusual for both ICE and EV. It’s unusual as a proportion of all cars, but it’s much less unusual as a proportion of cars requiring a repair.

Outliers exist, it happened to @markjay in an EV and it happened to me in an ICE, but hasn’t happened to all of his cars and mine, and it hasn’t happened to many members cars.

 

[BTB 500]

As do Li-ion batteries... from memory, Li-ion started replacing NiCad around the turn of the Century.... this is in spite of NiCad being less prone to catching fire as a result of physical damage, and being overall a safer product.

NiCd was really replaced by NiMH, which is still in use today. Li Ion (which did take off around 2000) gave a big leap in energy density, so was a huge enabler where weight/size were a prime consideration (mobile phones etc.).

I think that the main reason that EV battery tech is currently based on Li-ion, is that two decades ago one Elon Musk decided to rig together a pile of laptop batteries and cram them into a Lotus Elise after stripping away the original engine and transmission, and the rest is history.

Could be, but Li cells are still a big temptation for manufacturers because of the energy density. Other EV manufacturers could have gone with LiFePO4 from the start but range was always the key thing. Now safety is getting a lot more attention, which I think is why they are suddenly becoming more attractive.

Speaking of which, I was just reading about two firefighters being killed and another critically injured while dealing with an EV fire in a parking garage in Spain:

Electric Porsche accident sparked blaze that killed two firefighters and injured 15 others in Madrid garage | Sur in English

Jesús A., 34, and Sergio B., 27, died in the fire, while 15 other people suffered intoxication from the smoke when other vehicles in the communal garage started to explod

www.surinenglish.com

 

[Bellow]

Could be, but Li cells are still a big temptation for manufacturers because of the energy density. Other EV manufacturers could have gone with LiFePO4 from the start but range was always the key thing. Now safety is getting a lot more attention, which I think is why they are suddenly becoming more attractive.

I noticed one of the (car) manufacturers (cant remember which one but European IIRC) has moved from Li-Ion to lithium iron phosphate.
I'm not sure which battery tech is used in down-hole tools but I was told it wasn't Li-Ion as the aggro of transporting them (airfreight) was too onerous due to their volatility.

 

[BTB 500]

I noticed one of the (car) manufacturers (cant remember which one but European IIRC) has moved from Li-Ion to lithium iron phosphate.

It doesn't surprise me ... there's a fair bit of negative publicity about EV fires, so a 'safer' battery pack could be a good selling point now. I believe they are cheaper too.

 

[markjay]

I'm not sure which battery tech is used in down-hole tools but I was told it wasn't Li-Ion as the aggro of transporting them (airfreight) was too onerous due to their volatility.

Indeed. We ship lots of laptops, and the outer box has this warning label:

The Li-ion battery in a standard laptop is typically around 50 Wh.

(A mobile phone Li-ion battery is typically between 10 Wh to 20Wh)

 

[BTB 500]

Indeed. We ship lots of laptops, and the outer box has this warning label:

The Li-ion battery in a standard laptop is typically around 50 Wh.

IIRC for Li battery packs there are various capacity limits for different forms of shipping?