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Fast-charging can damage electric car batteries in just 25 cycles

November 26, 2020

By Paul Homewood



Fast-charging of electric batteries can ruin their capacity after just 25 charges, researchers have said, after they ran experiments on batteries used in some popular electric cars.

High temperatures and resistance from fast charging at commercial stations can cause cracks and leaks, said the engineers from the University of California, Riverside. 

The team charged one set of discharged lithium-ion batteries using the same industry fast-charging method found at motorway stations.

The researchers also charged a set using a new fast-charging algorithm based on the battery’s internal resistance, which interferes with the flow of electrons. The internal resistance of a battery fluctuates according to temperature, charge state, battery age and other factors. High internal resistance can cause problems during charging.

The algorithmic charging method – known as internal resistance charging – is adaptive, learning from the battery by checking its internal resistance during charging. It rests when internal resistance kicks in, to prevent loss of charge capacity.

For the first 13 charging cycles, the battery storage capacities for both charging techniques reportedly remained similar. After that, however, the industry fast-charging technique caused capacity to fade much faster – after 40 charges the batteries only had 60% of their storage capacity.

At 80% capacity, rechargeable lithium-ion batteries have reached the end of ‘use life’ for most purposes. Batteries charged using the industry method reached this point after 25 charging cycles, while batteries charged with internal resistance charging were good for 36 cycles.

“Industrial fast-charging affects the lifespan of lithium-ion batteries adversely because of the increase in the internal resistance of the batteries, which in turn results in heat generation,” said doctoral student and co-author Tanner Zerrin.

Even worse effects came after 60 charging cycles using fast industry charging. Electrodes and electrolytes were exposed to the air, increasing the risk of fire or explosion. High temperatures of 60ºC accelerated the damage and the risk.

“Capacity loss, internal chemical and mechanical damage, and the high heat for each battery are major safety concerns,” said researcher Mihri Ozkan.

Internal resistance charging reportedly resulted in much lower temperatures and no damage.

“Our alternative, adaptive, fast-charging algorithm reduced capacity fade and eliminated fractures and changes in composition in the commercial battery cells,” said researcher Cengiz Ozkan.

The technique could be used to improve safety and lifespan of car batteries.

The researchers have applied for a patent on the algorithm, which could be licensed by battery and car manufacturers. In the meantime, the team recommended minimising the use of commercial fast chargers, recharging before the battery is completely drained, and preventing overcharging.

The research was published in Energy Storage.


The paper is here.

It is not clear how fast the “fast chargers” are which the study tested. They talk of motorway service station standards, which in the UK tend to be 50KW. I don’t know if the US is much different.

However, their trials suggest two hour charging, which would imply 50KW as well.

If so, this will be a huge blow for anybody who needs to use public chargers regularly. You may be able to get away with the occasional rapid charge when you go on a long trip. But for those unable to charge at home, or who travel long distances regularly, anything slower than 50KW is a non starter.

Below is the chart from the study, showing how rapidly the battery capacity deteriorates. Even algorithmic charging method (IR) loses capacity quickly as well, dipping well below the 80% benchmark after about 40 cycles.



This whole saga highlights how electric cars are being pushed forward with no thought about the consequential problems.

In the normal world, technologies only take off once the obstacles have been resolved.

  1. November 26, 2020 12:55 pm

    Will their new BIG BATTERY technology solve this problem?

  2. November 26, 2020 1:06 pm

    Once again with ‘green energy’ the triumph of hope experience factor kicks in with enthusiastic optimism replacing basic science and common sense! To add yet more evidence that electric cars are useless in the long term, if more were needed! A few months ago in the excellent “Honest John” motoring column in Saurday’s Daily Telegraph, he was asked the following. A reader had an electric car tha could only be charged to 30% capacity the vehicle was five years old, should the owner buy a new battery HJ’s answer was no, either accept that the car can only be used for short journeys or scrap the car. Thecost of the new battery would be more than the car was worth!

  3. LeedsChris permalink
    November 26, 2020 1:18 pm

    At a slight tangent… has everyone seen how little electricity is coming from wind power in the UK today – it’s been stuck at 1 (one) per cent all morning! So despite the billions spent, the trashing of landscapes etc. At breakfast time this morning sun was ‘nil’ … thankfully coal was giving us 6 per cent and gas 62 per cent. Makes you wonder where all the electricity for cars and hone heating is going to come from when the last coal plant is closed mid decade and when we phase gas out…

    • John Palmer permalink
      November 26, 2020 2:38 pm

      Don’t worry! They’re working on a ‘Magic Electricity Well’ – if only they can shake enough fruit from the famous ‘Magic Money Tree’ (AKA the Taxpayers wallets….)

    • Steve permalink
      November 26, 2020 3:47 pm
      This site shows the total generation and consumption over the last year and how the demand drops after lockdown. The shares of generation also show that this winter we have less coal, less nuclear and probably less imports if we get a freeze up in an anticyclonic lull for a week after Christmas. No wonder they want lockdown to go on until spring.

    • Ray Sanders permalink
      November 26, 2020 4:40 pm

      You have to wonder how all those Scots are being conned. Whenever the wind dies down the power flow from Scotland to England turns into reverse and Scotland are at the mercy of English supply as they have been most of today. But you have to factor in the 2000MW that are being generated by Hunterston B and Torness. When they close (and the SNP refuse any nuclear replacement) then Scotland will inevitably be an almost continuous net importer from the only place it can i.e the rUK. Even the proposed privately funded interconnector from Norway to Scotland has been shelved and the stae funded one has deliberately bypassed Scotland.
      The SNP very much try to keep these sort of things secret.

    • Adam Gallon permalink
      November 26, 2020 8:36 pm

      More power coming from the evil coal!

  4. It doesn't add up... permalink
    November 26, 2020 1:28 pm

    And they think they want to degrade everyone’s batteries with V2G to keep the lights on? Delusional.

  5. GeoffB permalink
    November 26, 2020 1:34 pm

    Paul has hit the nail on the head, I could give you a detailed analysis of the currents, voltages and dissipation in the battery, but the problem is that the technology is being forced on us ahead of the learning curve. As problems come too light, instead of a few early adopters being affected, there will be thousands of disgruntled customers with problems. The same situation occurred with wind farms, too many inefficient first generation designs were forced on us.

    One thing that concerns me about the report is that Tesla super chargers are used all over California and there must be some real world, actual facts and figures on battery performance, analysis here would confirm or refute the reports findings. More info please…. at the moment I think the report is a bit lacking, testing just 2 batteries and most existing chargers reduce the energy as the battery charges and have temperature feedback from sensors in the battery. In fact the reputable battery chargers you use at home for rechargeable batteries, Lithium and Nickel hydride, use quite sophisticated charging algorithms, some have temperature monitoring as well.

    • MikeHig permalink
      November 26, 2020 4:43 pm

      Quite agree this needs a reality check. It reminds me of so much climate “science” where a bit of dodgy modelling is used as the basis for predicting armageddon tomorrow.
      They could easily have done a bit of on-the-ground research to see if their findings stand up. The fact they didn’t bother makes me suspect that they know they would come unstuck.
      According to the Tesla fanboys, there are cars working as taxis in the US which have reached many hundred thousand miles – that should provide useful data.
      This issue is a regular on EV websites as it is a known phenomenon so anyone looking at a used EV is advised to get hold of a widget which analyses the battery’s condition – including how it has been charged.
      Also a few minutes on the web would tell them that EVs control the rate of charge, precisely to address this issue.

    • November 26, 2020 5:11 pm

      Temperature monitoring and charging rate adjustment probably means that the overall charge is no longer “fast”.

  6. Pat permalink
    November 26, 2020 1:38 pm

    So basically, even with the advanced algorithm, your electric car is scrap after 40 fill ups?
    So much for!

    • Mad Mike permalink
      November 26, 2020 2:11 pm

      Yes, I’m truly surprised. If this is true you would have thought we would have heard more about this problem even from MSM. Even 200 cycles doesn’t get you very far through the year.

  7. November 26, 2020 2:10 pm

    Everything rechargeable seems to gradually die. I wonder how will the Tesla battery banks for emergency backup for the Grid will actually last. Boris’s dictate on ICE seems a bit premature like his (Princess Nut Nuts) whole green wet dream seems to be falling apart.

  8. Dick Goodwin permalink
    November 26, 2020 2:14 pm

    When I went through my electrians training in the 1970’s we were told then that the worst way to treat a battery was to put it in a car. Car batteries have obviously improved since the 70’s but long term electric car ownership for all is obviously just a pipe dream for the climate alarmists and many politicians.

  9. Mack permalink
    November 26, 2020 2:24 pm

    So, apart from having a very low range, even lower in winter, a short and occasionally explosive battery life utilising environmentally damaging materials (which are difficult to recycle) sourced from veritable slave labour camps in Africa and greater China, and costing an arm and a leg more than their ICE equivalents with poor re-sale values whilst being entirely reliant on electricity from an increasingly unstable grid, what’s not to like about EVs?

  10. Gerry, England permalink
    November 26, 2020 2:26 pm

    And the City of London Corporation will be getting solar power from Dorset to polish up its virtue-signalling. Given that is had to up its offer, this is no doubt above the normal cost for electricity.

  11. Ben Vorlich permalink
    November 26, 2020 2:30 pm

    One of my first jobs was working in an electrolytic capacitor manufacturing facility. One of the major issues was the Equivalent Series Resistance or ESR. It was a bit of a black art to manage, depending on several factors. But virtually every batch had a percentage of losses including a few bangs but mainly reduced capacitance due to drying out of the paper/electrolyte layers between the two foil layers. Fast charging means higher currents and heat generated is proportional to the square of the current.

    If the ESR increases, in the capacitors I worked with nearly 50 years ago, heat was often the cause of an increased ESR and the demise of the capacitor.

    I’ve often wondered if a Lithium Ion Battery works in a similar way to an Aluminium Electrolytic capacitor.

  12. ThinkingScientist permalink
    November 26, 2020 3:27 pm

    I just had to replace the lead acid battery on on my Landrover Discovery LR4 after 7 years. I was outraged it cost me just over £200.

    Anybody know how much a replacement battery is for an electric vehicle?

    • Rud Istvan permalink
      November 26, 2020 3:40 pm

      I own a Ford Hybrid Escape, my2007, Prius hybrid architecture. NMH traction battery at 390 volts. Is still functional with car at about 90k miles. A bit of leakage current in the starter compartment last two years, so if sits for a week voltage dropps below 350 and need to use the built in ‘jump start’ button (ports current from the traction compartment to boost starter compartment voltage). Is fine for about 5 days sitting. (So the issue was known to Ford at the beginning and a solution designed in.)

      A Replacement NMH battery for our Escape would be about $5k plus dunno labor.

      Replacement LiIon for Tesla model 3, parts plus labor, is about $16k in the US.

      • Curious George permalink
        November 26, 2020 4:53 pm

        Does this “jump start” button start the gasoline engine?

  13. Rud Istvan permalink
    November 26, 2020 3:29 pm

    For those familiar with LiIon batteries, this is not new news. It is a fundamental of the Nernst equation in electrochemistry. It is possible to design longer lived rapid charge/discharge (high power density) LiIon, BUT these always have low energy density—so a car equipped with such has a low mileage range.

  14. Steve permalink
    November 26, 2020 3:50 pm

    Perhaps the answer is to make all cars into mini camper vans so that we can sleep overnight beside a 13 amp charging point.

  15. John Peter permalink
    November 26, 2020 3:56 pm

    “The same situation occurred with wind farms, too many inefficient first generation designs were forced on us.” Where are the efficient designs installed? I have also been looking at Gridwatch and wind is still only at 0.77 GW = 1.8% of demand. Biomass in in the red area so DRAX is doing well. Coal was at 2.21 GW this morning.

    • It doesn't add up... permalink
      November 26, 2020 8:21 pm

      I don’t really see much change in wind turbine efficiencies at least in the true technical sense. There are potential cost per MWh savings from the larger turbines, mainly because of higher hub heights and therefore higher average wind speeds that can be expected. Designs are cost optimised for different wind conditions that might be expected. Windier locations may justify sacrificing lowering cut-in wind speed and running a larger generator that hits maximum output at a higher wind speed.

      Here’s a typical performance curve for a 3MW turbine: note that it measures the proportion of the total energy in the wind converted to power output (which can never exceed the Betz limit of 16/27ths), with the power outputs noted at each point (mouseover to see).

  16. rory green permalink
    November 26, 2020 4:21 pm

    Hi I’m not clear on what a “cycle” is. Is it one charging of the car equals one cycle? And how many miles does one charge do? From this study it would seem that the batteries would be, effectively, useless within a short period of time unless a “cycle” lasts for at least six months or so.RegardsRory Green

    • November 26, 2020 4:35 pm

      According to the paper battery is charged and then discharged, making one cycle

  17. David permalink
    November 26, 2020 4:36 pm

    I suspect that the extent of the problems with declining battery power is a hidden matter at the moment because most of the buyers of leccy cars are too embarrassed to admit their stupidity.

    • November 26, 2020 4:46 pm

      It would be interesting to see data on actual mileage done by electric cars. If, as some suspect, the majority are used as second cars by virtue-signalling brown ricers, they probably don’t do many miles, spend most of the time on the drive, and are never charged away from home.

      • Todd A Allcock permalink
        November 27, 2020 9:04 am

        I’m not a “brown ricer”, but I just bought an EV here in Colorado, USA as a “second” car. A new Nissan Leaf that cost me $15k US (after tax incentives). It has a 150 mile range (so far about 120 in “worst case” situations: winter cold, running the interior heater.)

        I live in the suburbs, and average about 30 miles/day driving, so overnight “slow” charging is more than adequate to keep the car charged, and we have a conventional gasoline car as a primary car for longer trips.

        In the two months we’ve owned the EV, we’ve put about 20 miles on the “primary” gas car, and over 2000 on the “secondary” car.

        Maybe the fuel cost of $3US/100 miles for the EV compared to $7 for the gas car, and the fact that the EV will need virtually zero maintenance other than tires in the next 100000 miles are pluses in its favor.

        I can easily see replacing the gas car with a second EV (one with a longer range “just in case” perhaps) at its end of life and using rental gas cars for very long trips (e.g. vacation road trips.) We already typically rent cars for vacations to reduce the milage and wear on our vehicles.

      • November 27, 2020 9:52 am

        @ Todd it sounds like you’re using it in a way that will enable you to always charge at home & keep the battery going longer, as well as eliminating range anxiety.

        I’ve just looked up the cost of a Leaf over here – from £27,000, which I believe includes the three thou gov’t discount.

        It will be interesting to see how this all shakes out. In 2030, I presume if those of us in the UK want to rent a car, it will have to be an electric one. So car hire companies are not going to do so well and people will keep old diesels running. On the other hand perhaps the ban will not apply to “commercial” vehicles, so there will be a get out clause there. We’ll all have to rent trucks.

  18. markl permalink
    November 26, 2020 4:56 pm

    Truth in advertising would go a long way with EVs. Advertised range is not the practical range when all the variables are taken into account: day or night driving, temperature, HVAC use, speed, electrical accessory use, terrain, and driving style all make a difference. The EV remains a niche vehicle for city dwellers or those willing to take into account its’ shortcomings and adapt.

  19. A C Osborn permalink
    November 26, 2020 5:13 pm

    I would have preferred it if this had come from engineers not trying to sell something though.

  20. Paul H permalink
    November 26, 2020 10:39 pm

    Is the forthcoming Motorway max speed reduction to 60MPH a sop to the EV community to help them eak out their car’s range when on a proper journey one may ask?

  21. November 26, 2020 11:16 pm

    There is no doubt batteries need to be nurtured. Like, I suspect, most people I am not good at that so have a draw full of duff rechargeables needing recycling.
    Heaven knows when these EVs start cluttering up our roads with batteries complaining about maltreatment.
    Changing stations will not be interested in the nurturing of your batteries.
    It is a minefield of unintended consequences.

  22. EyeSee permalink
    November 27, 2020 8:43 am

    The way Green policies are enacted is a reflection of basic Left wing orthodoxy. Basically, answer first then build a narrative to suit. This is why reality and Lefty ideas usually part company.

  23. James Broadhurst permalink
    November 27, 2020 1:07 pm

    This research is surely out of date. If you repeatedly charge and discharge a Li-Ion call to it’s upper, 4.25v, and lower, 2.65v, limits at anything approaching 1C which is the nomenclature used by the manufacturer to describe current, eg 3.4amps in a 3,400mAhr cell, you will rapidly damage it. Reputable, not Chinese, manufacturers give a maximum operating life of 500 cycles at much lower rates eg 0.3C. All this is well known.

    However, if your electric car operates well within the limits, you will achieve a much higher number of cycles as well as extending the life of the battery beyond the warranty term. This happens by the simple expedient of the manufacturer writing down the battery capacity. This gives another advantage by being able to promote your product as having an “80% charging capacity in 1 hour”. For example, if you manufacture a 125KWhr battery but market it at 100KWhr; the operating window narrows to something like 3.0 to 4.0 volts and you can handle charging rates much less than 1C (mathematically 1C should charge any battery in 1 hour but it won’t like it) which will give a 80% charge because it’s actually a 64% charge. The other trick is to write the software to prevent the user charging his car too often at 80%.

    What’s extraordinary about this is we just aren’t used to the idea of buying a car which understates its power.

    You hear of Tesla owners being granted additional capacity overnight during the pandemic by “new software”. That’s just shifting the upper and lower limits and the price to pay for that will be lower battery life.

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