EV Batteries

[steveting99]

In the EV battery space - BYD has some competition from their arch rival in the mainland. The Geely group has their own version of the blade battery called Aegis short blade - sometimes called the golden brick battery. See picture below.

The Aegis battery was announced back in mid-2024 (almost 1.5 years ago) and is now available to existing Geely Galaxy models such as EX5 / Proton eMas7. Some details are:

Length: 580mm

Thickness (width): 18.2mm

Energy density: 192 Whr/kg

Claimed charge cycles: 3,500

Chemistry: Lithium Iron Phosphate (LFP)

Separator: wet process with double coating

Separator coating: aluminum oxide

Length wise, its similar to BYD Blade battery 2.0 short version. The Aegis cell has a similar energy density, but the chemistry is the older type (LFP). In Geely’s design, the Aegis battery cell uses a ‘self-fusing’ tech on the electrode surfaces block short circuits in the event of an severe collision / accident. An aluminum foil layer fuses to the battery diaphragm to create an insulating layer that prevents dangerous thermal runaway events that can lead to battery fires. 3rd party test validation certificate from China Automotive Technology and Research Center (CATARC) on Geely's Aegis battery is shown below.

CarNewsChina article claims that Geely Aegis battery complies with the new GB38031-2025 "Safety Requirements for Power Batteries of Electric Vehicles" in the article here: https://carnewschina.com/2025/05/29/geely-galaxy-e5s-aegis-gold-brick-battery-passes-36-ton-tank-compression-test/, but would like to see CATARC's test certificate to be sure.

Similar to BYD, Geely also implements the cell to body design on their Aegis batteries. Geely claims the battery pack claims to be IP68 / IPX9K protection rating, based on their CTB (Cell To Body) integration technology. Should be able to wade through and survive flash flood situations. Picture of the structural battery pack for a vehicle is shown below.

  

Geely's Aegis battery also has excellent cold weather performance (not that it matters here in sunny, tropical Singapore) by retaining 90.54% of capacity at -30 deg C.

In a presentation event, Geely/Proton confirmed that the battery pack is the highest cost item in an EV, about 40% of the Bill of Materials (BoM). Article from DriveSafe&Fast is here: https://www.dsf.my/2024/12/proton-e-mas-7-uses-geelys-short-blade-and-its-better-than-youd-think/

Longevity of the Aegis battery is very good. Endurance test after 300,000 kms and 921 charge cycle shows the battery pack retaining 90.5% of it's original capacity on the Galaxy EX5 according to this article here: https://en.eeworld.com.cn/news/qcdz/eic674502.html

DC fast charge is slower than BYD's Blade battery 2.0 short version. Around 2.45C charge rate according to CarNewsChina article here: https://carnewschina.com/2024/06/28/geelys-aegis-short-blade-lfp-battery-full-details-including-extreme-safety/. 

Believer Geely's Zeekr 7X RWD Standard version uses the 75kWhr Aegis battery pack. 

[steveting99]

On 2-May-2025, Contemporary Amperex Technology Co., Limited (CATL), the world’s largest battery manufacturer, has announced that it is the first company to comply with China’s new “No Fire, No Explosion” national safety standard for batteries. I.e. GB 38031-2025 which comes into affect on 1-Jul-2026. Electrive article is here: https://www.electrive.com/2025/05/02/catl-batteries-meet-new-thermal-runway-standards/

CATL claims their Qilin batteries that were introduced in 2022 complies with GB38031-2025. Both NMC and LFP chemistries. Sample test certificate from China Automotive Technology & Research Center (CATARC) are given below.

Vehicle manufacturers Aito, Zeekr, Li Auto, Xiaomi, Neta, Avatr, and Lotus incorporates the Qilin battery into their electric vehicle models.

[steveting99]

Donut Labs has released their 4th test result and this time, its not from a lab - but from an actual production vehicle using their solid state battery. The Verge motorcycle.

Review video again from one of my favorite tech YouTubers (Two bit da Vinci) is here: 

Several things stand out on this 4th test. 

(1) It's the fastest charging e-bike in the world at the moment. 10% to 50% in five minutes. 10% to 70% in nine minutes. 10% to 80% in 12 minutes!

(2) The test is at the pack level and not at the cell level like the first three tests.

(3) The charge rate is over 5.7C and sustained for some duration (about five minutes). Unlike most where it's just a peak then the BMS would throttle down to prevent overheating and risk thermal runaway. The e-motorcycle battery packs are air cooled and not liquid cooled, so there's room to increase the charge rate further if liquid cooling is provided. This will be the case if the packs are in a four wheeled vehicle.

(4) Missing tests are: 

(a) Energy density in W/kg. This should be easy to do.

(b) Cold temperature tests. This should be easy to do.

(c) Battery cell chemistry. This should be easy to do.

(d) Longevity of 100,000 cycles. This will take time and a bit more difficult to do, but not impossible. Can shorten the duration by carrying out 11C charge and discharge cycle and plot the battery curve. Can do about 43,800 cycles in a year and compare against the 1C charge / discharge cycle test as a comparator which would have done around 4,380 cycles.  

The Verge e-motorcycle will be made available this year (2026). 

[steveting99]

5th test result from Donut Labs has been released and analysis carried out by Ricky from Two Bit Da Vinci here: 

A few things to note from the 5th test.

(1) The damaged pouched cell (from the high temperature test carried out by VTT, i.e. No.2 video) still continues to work at a significant reduced capacity of around 50%. Failure of the pouch did not cause thermal runaway event that's typical for liquid electrolyte cell. Looks like safety to be better. A nail penetration test of Donut Labs cell would have been more convincing on safety.  

(2) Ricky thinks the 5th test indicates its a solid state battery cell. However, there's still some answered questions.

Those unanswered questions are leading to frustration, fatigue and disinterest on Donut Labs. Important and simple tests to verify energy density and cold weather performance are being deliberately withheld. If Donut Labs continues down this path, no one is going to care about them anymore.

 

 

 

Edited March 25 by steveting99
additional text

[Rm2s]

MG has confirmed that it will be the first manufacturer to introduce semi-solid-state batteries in the UK, beating rivals such as Toyota and Nissan who have been talking about the revolutionary tech for several years. Semi-solid-state batteries are a new technology that chiefly benefits electric car drivers by bringing increased safety and charging performance at a lower cost. It will be used in the MG4 Urban in the UK, later in 2026. 

The new MG ‘SolidCore’ battery will be the first mass-produced semi-solid-state battery to go on sale in Europe, and while it will go in the MG4 Urban EV first, there will also be two new models – potentially a new sports saloon and a family SUV, if sneaky images that I saw at the tech reveal at the company’s Frankfurt HQ is anything to go by.  

Full article here:

https://www.electrifying.com/blog/article/mg-to-introduce-semi-solid-state-batteries-in-2026

Also MG has previewed the new MG4X in China, a SUV version of the MG4 Urban, which is said to be using the semi-solid state batteries as well.

[steveting99]

According to BYD's press release, their new 2nd generation Blade Battery 2.0 and the flash charging system has passed all tests to achieve the new battery national standard (GB38031-2025), obtaining certification from the China Automotive Technology and Research Center (CATARC) shown below.

Press release is here: https://www.byd.sa/en/news/blade-battery-flash-charging/

CATARC test certificates are from EE World article here: https://en.eeworld.com.cn/news/qcdz/eic696805.html#:~:text=On May 27%2C BYD Group,meeting the insulation resistance requirements.

China EV Home article here: https://chinaevhome.com/2025/05/27/byds-blade-battery-flash-charge-blade-battery-pass-new-national-standard-ahead-of-schedule/#:~:text=This morning%2C Li Yunfei%2C general,and technological thresholds in history. has some additional information about Blade Battery 2.0

 

[deutfalke]

I’ve started looking around for my next car and will likely make the jump to EV. My main concern right now is battery health, especially in Singapore’s climate and usage patterns.

Came across this article from sgCarMart:
https://www.sgcarmart.com/articles/advice/ev-battery-warranty-a-comprehensive-guide-36882

From what I understand, most brands here offer around 8 to 10 years warranty with about 70% battery health guarantee, which sounds reassuring on paper.

But I’m curious about real world experiences. Has anyone here actually gone through the process of claiming EV battery warranty locally? Was it straightforward or a headache?

The only case I’m aware of is the Taycan dispute, where warranty didn’t apply after an accident because damage was attributed to the collision. That one seems quite messy.

Also a bit worried about the fine print, like whether they might reject claims due to things like minor undercarriage damage, scratches, or anything that could be argued as external damage rather than a manufacturing defect.

[Solar]

On 4/30/2026 at 5:49 PM, deutfalke said:

I’ve started looking around for my next car and will likely make the jump to EV. My main concern right now is battery health, especially in Singapore’s climate and usage patterns.

Came across this article from sgCarMart:
https://www.sgcarmart.com/articles/advice/ev-battery-warranty-a-comprehensive-guide-36882

From what I understand, most brands here offer around 8 to 10 years warranty with about 70% battery health guarantee, which sounds reassuring on paper.

But I’m curious about real world experiences. Has anyone here actually gone through the process of claiming EV battery warranty locally? Was it straightforward or a headache?

The only case I’m aware of is the Taycan dispute, where warranty didn’t apply after an accident because damage was attributed to the collision. That one seems quite messy.

Also a bit worried about the fine print, like whether they might reject claims due to things like minor undercarriage damage, scratches, or anything that could be argued as external damage rather than a manufacturing defect.

In my opinion like an ICE car, if u get into accident, warranty likely don't cover already, but have to claim thru insurance. Similar when you mod the car out of it's original state.

Or when you damage your side mirror against the wall, u don't go claim warranty but own insurance.

The case u quoted, it's weird that insurance push away, probably something illegal was involved, like unlicensed driver?

Or the details wasn't shared in the news article, the owner didn't want to do own claim?

[simon_simon]

On 3/25/2026 at 2:07 AM, steveting99 said:

....Those unanswered questions are leading to frustration, fatigue and disinterest on Donut Labs. Important and simple tests to verify energy density and cold weather performance are being deliberately withheld. If Donut Labs continues down this path, no one is going to care about them anymore.

On 17 April,Nordic Nano Group, an R&D company working with Donut, told Finland’s media that the Donut's solid state battery claims were simply not true, and filed a criminal complaint with government officials. Lauri Peltola, chief commercial officer of Nordic Nano, told the paper that Donut had exaggerated its claims, and misrepresented its ability to go into mass production.

Liar Liar, Pants on Fire. 😜

 

[Lethalstrike]

On 4/30/2026 at 5:49 PM, deutfalke said:

I’ve started looking around for my next car and will likely make the jump to EV. My main concern right now is battery health, especially in Singapore’s climate and usage patterns.

Came across this article from sgCarMart:
https://www.sgcarmart.com/articles/advice/ev-battery-warranty-a-comprehensive-guide-36882

From what I understand, most brands here offer around 8 to 10 years warranty with about 70% battery health guarantee, which sounds reassuring on paper.

But I’m curious about real world experiences. Has anyone here actually gone through the process of claiming EV battery warranty locally? Was it straightforward or a headache?

The only case I’m aware of is the Taycan dispute, where warranty didn’t apply after an accident because damage was attributed to the collision. That one seems quite messy.

Also a bit worried about the fine print, like whether they might reject claims due to things like minor undercarriage damage, scratches, or anything that could be argued as external damage rather than a manufacturing defect.

You really have to read the fineprint especially for Chinese brands offering 10 year battery warranty here. 

With BYD, its 10 years or up to 200,000km (8 years + 2 years extention) but the guarantee for battery State of Health retention goes lower to 60%, rather than 70%. It means they have already done their homework and calculated there is a very low chance of the battery to degrade a further 10% in the last 2 years, from the usual 70% retention guarantee within the first 8 years. To the end user, if your battery degrade till 70% SoH in the last 2 years, it doesn't fulfill the battery warranty clause for a traction battery replacement. Most BYD owners probably do not know this but they bought the car simply because of the 10 yrs warranty at face value. In other words, I can give you 20 years battery warranty but SoH degradation clause in fine print can be very low at 30%. Meaning, there is almost no chance of the manufacturer honouring the warranty as this clause is heavily skewed in the its favour 😁

Edited May 3 by Lethalstrike

[simon_simon]

On 5/3/2026 at 5:00 AM, Lethalstrike said:

You really have to read the fineprint especially for Chinese brands offering 10 year battery warranty here. 

With BYD, its 10 years or up to 200,000km (8 years + 2 years extention) but the guarantee for battery State of Health retention goes lower to 60%, rather than 70%. It means they have already done their homework and calculated there is a very low chance of the battery to degrade a further 10% in the last 2 years, from the usual 70% retention guarantee within the first 8 years. To the end user, if your battery degrade till 70% SoH in the last 2 years, it doesn't fulfill the battery warranty clause for a traction battery replacement. Most BYD owners probably do not know this but they bought the car simply because of the 10 yrs warranty at face value. In other words, I can give you 20 years battery warranty but SoH degradation clause in fine print can be very low at 30%. Meaning, there is almost no chance of the manufacturer honouring the warranty as this clause is heavily skewed in the its favour 😁

3 BYD owners I asked all say their EV battery warranty covers SOH>=70%. Another in Auckland confirm similar b/w.

I am curious where did you got that  doc from and for which model ?

 

[Lethalstrike]

On 5/3/2026 at 12:02 PM, simon_simon said:

3 BYD owners I asked all say their EV battery warranty covers SOH>=70%. Another in Auckland confirm similar b/w.

I am curious where did you got that  doc from and for which model ?

 

There you go...

https://www.byd.com/sg/support/service/warranty-policy

 

[simon_simon]

On 5/3/2026 at 6:59 AM, Lethalstrike said:

There you go...

https://www.byd.com/sg/support/service/warranty-policy

Telsa also has similar clause:  https://www.tesla.com/en_sg/support/vehicle-warranty. Seems 8 years for  SOH>=70% is an unofficial industry min.

• 8 years or 160,000 km, whichever comes first, with minimum 70% retention of Battery capacity over the warranty period. 

That 10-Year (extended) warranty obviously is a marketing tactic since the decade-figure will standout more than the usual 8-years for most folks.

That extra +2 years for SOH>=60%  clearly includes increasing risk from natural SOH degradation beyond the 8th year.

Yeap, like you had pointed out, BYD, as one of the battery king, had clearly done its homework. 😜

 

[Lethalstrike]

On 5/3/2026 at 5:39 PM, simon_simon said:

Telsa also has similar clause:  https://www.tesla.com/en_sg/support/vehicle-warranty. Seems 8 years for  SOH>=70% is an unofficial industry min.

• 8 years or 160,000 km, whichever comes first, with minimum 70% retention of Battery capacity over the warranty period. 

That 10-Year (extended) warranty obviously is a marketing tactic since the decade-figure will standout more than the usual 8-years for most folks.

That extra +2 years for SOH>=60%  clearly includes increasing risk from natural SOH degradation beyond the 8th year.

Yeap, like you had pointed out, BYD, as one of the battery king, had clearly done its homework. 😜

 

Very right. The industry standard is 8 years or 160,000km whichever comes first, at minimum 70% SoH. 

[simon_simon]

And speaking of battery warranty, I hv the pleasure to share BYD's new Blade2 battery has improved 8th years SOH figures.

On top of its 1.5GigaWatt Flash-charging platform, the next EV models are gonna be another level of 10-minutes charging experience.

🤗

[steveting99]

For those who are worried about the longevity of the high voltage battery pack, the following simple calculations should assuage those fears.

Determine the WLTP range of the ride and its battery pack capacity. For example, BYD's Sealion 7 Dynamic WLTP range is 405km and battery capacity is 71.8kWhr.

Get the battery curve from vehicle/battery vendor to determine number of cycles it can do and it's related State of Health (SoH). For the Sealion 7 Dynamic, the 1st gen BYD blade battery cell is CBV4A and after 3,000 cycles the SoH will reach around 84%. See previous post on the battery curve. A charge and discharge cycle is counted when the battery pack goes from 0% to 100% and back down to 0%. So if one tops-up the battery pack in 25% increments from say 50% to 75%, it only counts as a quarter cycle. One would need to do four quarter top-ups to do one cycle. I.e. 4 x 25% top ups to reach one charge and discharge cycle. 

For every cycle, there's some loss due to keeping the lights, HVAC, music/radio, electronics, etc. running. Other factors that impact driving range (hence the freqeuncy of the charge/discharge cycle) are; how heavy the right foot is, city vs. highway driving, weather conditions, load carried, etc. YMMV as the saying goes, so the de-rating factor is not fixed. A 20% seems a good average number to go by as a derating factor.

So the simple equation for approximate distance traveled works out to be:  WLTP range * max cycles based on battery curve * (1-derating factor)

For the Sealion 7 Dynamic the approximate distance traveled based on 3,000 cycles as shown in the battery curve is: 405 kms * 3,000 * (1-0.2) = 972,000 kms.

There is also another point to consider and that's the battery degradation as the battery losses capacity over time. Looking at BYD's 1st gen blade battery curve, there's around 16% loss by the 3,000th cycle. Take the degradation loss upfront to be conservative and determine the estimated distance traveled after maximum number of cycles based on the battery curve.

Hence, the estimated distance one can get from a ride is : approximate distance traveled * (1 - battery degradation factor).

For the Sealion 7 Dynamic the estimated distance works out to be : 972,000kms * (1 - 0.16), which is around 816,480kms after 3,000 cycles.

If one does 40,000kms a year - twice the normal average for Singaporeans, it would take a little over 20 years (or two CoE cycles) before the battery's state of health reaches 84% or 60.3kWhr. The battery pack has plenty of life left and can still continue to operate - long before the vehicle goes to the scrap heap. The battery pack will most likely be good enough to be re-used for grid scale energy storage system, so there's some value and thus money left in the battery pack. I.e. the value of the battery pack is not zero. Don't let anyone fool you in saying otherwise. 

 

Edited May 3 by steveting99
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[Jiangwei]

@simon_simon I saw that and asked my SE before i booked my EV. He confirmed that it is 10 years at 70% SOH for the battery warranty.

I got him to write that in my sale agreement and sign. 

[steveting99]

This is follow up post to those who are worried about the longevity of BEVs compared to ICE vehicles. The following picture should should give you some ideas.

The above picture is curtesy of an article in CarScoops by author Stephen Rivers here: https://www.carscoops.com/2025/01/evs-evolved-rapidly-now-last-just-as-long-and-are-more-reliable-than-ices/ and he's referencing the Journal of Nature Energy large study in the UK that looked at 264 million records and 29.8 million vehicles from 2005 to 2022. The main dataset comes from UK's Ministry of Transport (MoT) and it's anonymized. To ensure that a vehicle is roadworthy and meets the minimum requirements, the UK's MoT requires a test to be carried out on the vehicle once a year upon the vehicle reaching its 3rd year of use or older.  This is a legal requirement. Researchers wanted to find out about the longevity of EVs compared to ICE vehicles. Breakdown on vehicle fuel types as follows:

Petrol : 15.1 million

Diesel: 14.7 million

BEV : 41.6k

Excluded in the study are PHEV vehicles, which comes to 371.3k. 

The peer reviewed Journal of Nature Energy is available here: https://www.nature.com/articles/s41560-024-01698-1#Sec5 and one can download the findings.

The reliability of BEVs have improved dramatically over the years. CarScoops article says:

"The study found that, for every year of production, the likelihood of failure dropped by 12%, a figure that’s notably higher than the 6.7% improvement for gas engine vehicles and a mere 1.9% for diesels. In other words, if you’re considering a BEV, the chances of it not breaking down are dramatically higher with each newer model, making those early EV hiccups seem like a distant memory."

While early BEV adopters from 2005 had issues, newer models are gotten better and are more reliable. This is confirmed by others who have looked into the large pool of BEV vehicles such as Recurrent in north America, Generational+ in the UK and GeoTab. 

Edit: The following graphs from Nature Energy may be useful to look at longevity and improvements on reliability.

Note the cohort ended in 2017.  A follow up study from 2017 to 2022 would be useful to see if the trends are going in the right direction for BEVs. At some point in time, BEVs are expected to surpass ICE in terms of longevity.

Edited May 4 by steveting99
typo, pic and additional text