UC Riverside Engineers: Current Fast-charging is damaging

[Tam]

Fast-charging damages electric car batteries

Two UC Riverside engineering professors led the research and found that Industry Fast-Charging, like Tesla's, subjects batteries to heat and resistance which then causes cracking, leaking, and capacity loss.

They have found the cure by using a new adaptive fast charging algorithm based on internal resistance. It claims "no damage"!

They recommend minimizing the use of commercial fast chargers!

I am not sure they'll be hired to do research for Tesla any time soon based on this kind of work

Heat and internal resistance are well-known issues and that's why Tesla has an active HVAC system for the main battery and variable charging rates as high as 250 kW to zero.

It sounds like they did not use a liquid cooling system in their tests.

 

[Watts_Up]

It sounds like they did not use a liquid cooling system in their tests.

Tesla pre-heat the batteries before going to a Supercharger and then control the temperature and the charging rate during the charging.

 

[EldestOyster]

new adaptive fast charging algorithm based on internal resistance

I bet it starts out at a high charge rate, and then tapers down as the battery fills up!

 

[user212_nr]

So before cycling the battery is green, after it is given a silver coating!

This article is very much clickbait misinformation. "Just 25 industry-standard fast charging cycles can ruin a car’s batteries", well there are people who supercharge 25 times in one week and have no reports of "damage".

Other than that, we already know that fast-charging can contribute to battery degradation. Degradation is the word we use rather than damage.

Also its worth noting that the cells were not Tesla cells, and that they are trying to improve the cells and the charging process (which is what Tesla has already done).

 

[jensk2]

Hmm, I use the exact same batteries for my fossile car 12V battery maintenance charger These I charge with 1/3C from 10-60% SoC to preserve battery life. I would never consider charging like UC do and I would not state, that the charging protocol that UC implemented mimics Tesla Fast Charging.well

Below is first the ABRP Official Curve for my Tesla Model S 70D SUC charge profile. Below it, I have drawn a 'copy' of the ABRP graph versus the UC Report stated Charge Profile. Not a very good good Model S look alike. (UC = CI=2C till 60%, then Rest, then CII=0,5C untill 4,2V then CV)

The simulation COULD be relevant for Audi Charge profile, but Audi uses NMC not NCA. The Model 3 LR does charge a little like the UC simulation (long flat max) but not with 2C~150kW, but it does do 125kW.
Comparing with Tesla Model S is as well imprecise, because my Model S only discharge to 3.0V, not the 2,5V UC did

 

[jensk2]

The published paper Error - Cookies Turned Off has an interesting section:

4 | SUGGESTIONS FOR FUTURE RESEARCH
4.1 | Impact of GITT During our capacity data analysis, we observed a significant increase in capacity after conducting a GITT procedure (Figure 12). This is due to the slow discharge of the battery during the GITT procedure. Since the battery is discharged at a rate of C/10, the mass transport of lithiumions to the cathode can be completely achieved. The battery is charged from a lower state of charge compared to our 0.5C discharge during normal cycling. Such phenomenon is worth investigation because GITT and pulsed charging are one of the most commonly adopted techniques in academia and in the industry. Further research that can reveal the reaction mechanisms can help the researchers and companies to use the techniques wisely and secure the safety and performance of the batteries in real applications.

This european engineers (like me) consider Capacity Recovery from Anode Overhang, which occur whenever the battery is left at low SoC or cycled slowly and low enough for prolonged periods of time. A good paper on this is: Investigation of capacity recovery during rest period at different states-of-charge after cycle life test for prismatic Li(Ni1/3Mn1/3Co1/3)O2-graphite cells - ScienceDirect
And Keil has it in his BEV Paper as well (Keil paper is a better reference, because he used Panasonic NCA for his tests)

(Best practice for my Car is: Whenever returning from a long trip, where I have either Super Charged or been above 55% SoC for prolonged periods of time, I make sure to arrive home below 55% and delays charging as long as possible, to recover the most. SUC on your way home and leaving car at high SoC over night is the worst)

 

[guitarman]

The problem with that report is that they are not comparing apples to apples. They are charging a battery that isn't exactly like the Tesla, isn't in a module or pack that is heated/cooled, under constant battery monitoring, or using the charging algorithm Tesla uses under all sorts of differing conditions (SOC, temperature, etc.). Tesla has far more experience with batteries in autos than anybody on the planet. And the data is out there already in terms of degradation.

 

[user212_nr]

The problem with that report is that they are not comparing apples to apples. They are charging a battery that isn't exactly like the Tesla, isn't in a module or pack that is heated/cooled, under constant battery monitoring, or using the charging algorithm Tesla uses under all sorts of differing conditions (SOC, temperature, etc.). Tesla has far more experience with batteries in autos than anybody on the planet. And the data is out there already in terms of degradation.

It is a mix of clickbait and shoddy reporting. Clickbait because they make an extreme claim in order to get clicks, "shoddy reporting" because they did not contact Tesla for comment. They took one source at face-value to get more money. If the article was titled "Report into battery degredation and temperature correlations, similar to what we already know" there would be no clicks.