Weltmeister EX5 impresses with low battery capacity degradation
Launched last year in China the Weltmeister EX5 is currently listed with a starting price of 139.800 yuan (17.561 euros) after subsidies. This is a very appealing electric car sized between the Kia e-Niro and the Tesla Model Y.
Let’s see some of its specs:
- Wheelbase: 2.703 mm
- Length: 4.585 mm
- Width: 1.835 mm
- Height: 1.672 mm
- Motor: 160 kW and 315 Nm of torque
- Acceleration: 0-100 km/h in 8,3 seconds
- On-board charger: 6,6 kW
- DC fast charging: 30 to 80 % in 30 minutes at 120 kW chargers
- Battery capacity: 69 kWh with lifetime warranty
- Battery weight: 432 kg
- Battery energy density: 160 Wh/kg
- Range (NEDC): 520 km (323 miles)
Considering that range in WLTP is roughly 3/4 of NEDC, in a more realistic test cycle the range would be around 390 km (242 miles). Not bad at all considering the price.
Now the automaker has some battery data to share with us.
To help alleviate concerns surrounding one important consideration among car buyers, the degradation of EV batteries over time, WM Motor has long promoted the benefits of high-quality thermal management and battery management systems (BMS) in EV’s to maintain the long-term stability of a battery’s capacity. Data from one of WM Motor’s EX5 models purchased in January 2019 has provided an insight into the car’s long-term battery degradation rate. The driver of this EX5 undertakes lengthy commutes between Wenzhou, Ningbo and Hangzhou, among other cities, and has averaged approximately 500km daily and accumulated over 200,000km of driving since purchasing the vehicle last year. Having been brought in for a regular check-up this week, the battery was found to have degraded by only 2.85% from its original capacity.
Battery data after 200.000 km (124.274 miles):
- Charged 90 % of the times at DC fast chargers
- Charged over 1.500 times (partial charges)
- Battery capacity only dropped by 2,85 %
Battery pack of Weltmeister EX5
There are multiple of factors that influence battery degradation. One such factor is the method used to charge the battery, with the general rule being that the faster a battery is charged on average, the faster that battery will degrade over its lifetime. This EX5’s capacity retention rate of 2.85% after 200,000kms would be extremely high compared to the industry standard even if the vehicle was most often charged at a slow, alternative current (AC) home charger. However, due to the vehicle owner’s long-distance travel requirements, the vehicle was charged using public fast direct current (DC) chargers approximately 90% of the time, which makes a 2.85% degradation rate even more noteworthy. At the time of testing, the vehicle had been put on charge over 1500 times.
Update
WM Motor contacted me to inform that these battery cells in the EX5 are NCM 811. I’ll update with more information if I get it.
Anyway, since the arrival of modern NCM 523 and NCM 622 batteries in late 2016 we can have high mileage electric cars that lose very little battery capacity and range. They just need a decent TMS (Thermal Management System) and to have their batteries cycled at lower SOC (State-of-Charge) with a good BMS (Battery Management System).
However, I recognize that all this recent marketing around million-mile batteries is very important to change people’s perception about electric cars. We can’t forget that some first generation electric cars gave really bad reputation to EV batteries with their extremely high degradation rates.
More electric cars like this one that has a lifetime battery warranty or the Lexus UX 300e that offers a 10-year or 1 million km warranty on its battery might be needed to provide peace of mind to most potential EV customers.
More info:
Wow, this is impressive. Also, this EX5 is quite a bit bigger than an e-niro, at about 20cm longer, as well as taller and wider, so a good sized long range EV for this price is also impressive. Fast charging is also OK.
Very impressive indeed, especially considering that subsidies in China are no longer very high. In 2020 they are at best 22.500 yuan (2.826 euros), depending on range and battery energy density.
To get the full subsidy the battery energy density needs to be higher than 160 Wh/kg and the range superior to 400 km (NEDC).
Impressive. Here is another surprising news.
Ford Escape/Kuga Plugin has the same 41 MPG which translates to 16 km/l when it runs on petrol/gasoline just like the Ford Escape/Kuga Hybrid.
How is it possible since the 14.4 KWh battery of the plugin should weigh much heavier than the 1.4 KWh battery of the hybrid version. Is it real or some mistake has happened.
https://www.fueleconomy.gov/feg/Find.do?action=sbs&id=42743&id=42253
I must say I am a little bit skeptical. This is one car and the press statement has been issued by the manufacturer, so not the most impartial of parties. Batteries have come a long way, but this sounds too good to be true, unless the battery has been designed with a generous buffer that has been depleted before degradation was noticeable.
I don’t know why you’re skeptical. Just look at the specs of NCM 811 battery cells from CATL.
https://pushevs.com/wp-content/uploads/sites/6/2018/02/ncm811-vs-ncm523-cycle-life.png
If we consider that a charge/discharge cycle is enough for on average 400 km, after 200.000 km the battery went through 500 cycles.
Looking at the chart above we should still have 95 % of the initial battery capacity after 500 cycles. The 2,85 % degradation can be explained by cycling the battery at lower SOC with fast charges.
The charts seem to more or less support the claim, but I’ve always been a bit skeptical about charts as well, since they are often based on extrapolations of lab tests rather than real life.
Moreover, cycle life will also depend a lot on the type of fast charging used. If the car charges at 70 kW then that’s indeed 1C, but if they used 120 kW that means 1.7C and therefore a lot more stress on the battery.
I must confess, even if degradation had been 5%, that would be a great number that shows that battery cycle life needs not be a concern (although calendar life is still a bit of an unknown).
Charging 30 to 80 % of the 69 kWh battery in 30 minutes represents less than 1 C, because it’s 50 % of the usable battery capacity, not total.
We know that when automakers mention the max supported DC fast charging rates is more marketing than anything.
I’m curious to see how well the NCM 712 battery cells from LG Chem used in the new Renault ZOE compare to these ones.
You’ve got me there with the C rates :). OK, I’ll give them the benefit of the doubt, but I would like to have proof from a wider sample than 1 car before I am really convinced.
Yeah, me too. I want to see these Chinese electric cars sold and tested in Europe by the thousands.
If you only charge at 1C and 50% of the capacity, I don’t think you will reach 400 km of range and if you drive 200.000 km you probably do that with a higher speed and therefore lower range.
Also the article states that the car had more than1500 cycles or at least charges and with 1500 cycles we are at under 85% of capacity according to your chart.
Lars, don’t confuse charges with cycles.
Imagine you have a 50 kWh battery and decide to charge every time you use 10 kWh. After 5 partial charges/discharges of 10 kWh each, it only counts as 1 cycle.
I am aware of that, but like I wrote, if you drive 200.000 km in a short time you will not be driving slow and therefore your range on each charge won’t be the 400 km. So maybe the battery didn’t make 1500 cycles, but most probably more than 500 cycles. If the owner drove 500 km a day and he didn’t charge a full cycle, he changed at least twice a day.
What do you expect from the new Zoe regarding degradation on 22kW AC charging and DC fast charging?
It’s still early to say, but I expect it to do fairly well (less than 10 % lost after 300.000 km). Usually the Renault ZOE is much more likely to have problems with its drivetrain than with its battery.
I hope that Renault with the new generation ZOE has finally made its electric drivetrains more reliable.