New charging method could double the life of Li-Ion batteries!

[thewayne]

The real interest here is battery electric and hybrid vehicles as those batteries are huge and expensive, but it would also be cool if you could double the service life of your smart phone or tablet battery!

The issue is pretty simple. We've always charged batteries using Constant Current (CC), where we apply a constant voltage and current to the batteries until they charge. We do it because we've always done it that way, and it's really, really easy from an electronics standpoint. I could sketch you a basic rectifying circuit to convert AC to DC at any given time, and that is what a charger does. The problem is, it increases the thickness of the anode of the Li-Ion battery, which decreases the battery's life.

Enter Pulse Charging (PC). With Pulse Charging, you're needing a more intelligent charging apparatus (okay, doable) that is introducing brief bursts (pulses) of electricity into the battery. This does not lead to anode thickening over time, and subsequent study of the test batteries shows that they can nearly double the life of the battery while retaining 80% of its capacity!

From the article: "The batteries were either charged conventionally with constant current (CC) or with a new charging protocol with pulsed current (PC). Post-mortem analyses revealed clear differences after several charging cycles: In the CC samples, the solid electrolyte interface (SEI) at the anode was significantly thicker, which impaired the capacity.

The team also found more cracks in the structure of the NMC532 and graphite electrodes, which also contributed to the loss of capacity.

In contrast, PC-charging led to a thinner SEI interface and fewer structural changes in the electrode materials."

and...

"The pulsed current charging promotes the homogeneous distribution of the lithium ions in the graphite and thus reduces the mechanical stress and cracking of the graphite particles. This improves the structural stability of the graphite anode," he concludes.

The pulsed charging also suppresses the structural changes of NMC532 cathode materials with less Ni-O bond length variation.

...

However, the frequency of the pulsed current counts: High-frequency PC charging protocols with square-wave current extend the service life of commercial LIBs the most, with a doubled cycle life (with 80% capacity retention) achieved in this study. Co-author Prof. Dr Julia Kowal, an expert in electrical energy storage technology at TU Berlin, emphasises: "Pulsed charging could bring many advantages in terms of the stability of the electrode materials and the interfaces and significantly extend the service life of batteries."

Very cool stuff. And since this is charging methodology, you're not changing the battery technology - though that's improving at a fairly rapid pace - so this should be implemented fairly easily. For certain values of the word easily.

There were a couple of things in the article that I didn't see that I'd like more information on. They didn't talk about any difference in heat of the test batteries during the charging cycles of the two methodologies, nor did they talk about any difference in the charging times. Both of those have some importance in a variety of applications.

It will be very interesting to see how this develops into field-deployed tech.

https://www.sciencedaily.com/releases/2024/04/240409123909.htm

https://hardware.slashdot.org/story/24/04/14/020205/could-a-new-charge-double-the-service-life-of-li-ion-batteries

Comments

[kathmandu]

Neat, and hopeful news!

[acelightning73]

I have always found square waves interesting. If you add together enough different sine waves, you get a square wave. That makes synthesizer square wave voices sound like deep-voiced woodwinds with tons of harmonics.

I don't understand why my cell phone tells me "You can charge this phone faster by only using the charger and cord that came with the phone." My husband, who has the same model phone I do, uses a charger that plugs into the car's "cigarette lighter", and he says it charges faster than the normal charger does.

So how do I make my phone charger intermittent without building a whole new circuit?

[thewayne]

Well, I'd say a 555 timer controlling a relay, that would be a pretty basic and simple implementation for a low voltage/current implementation.  The issue is not knowing what pulse rate to apply.

[acelightning73]

I expect to see cheap versions of speed chargers for sale in a bin next to the cash register in a truck stop. Then I'll buy one, along with a Cow Tail milk caramel candy and a large unsweetened iced tea...

[arlie]

This is very cool! Thanks for bringing it to my attention.

[thewayne]

I like cool stuff like this, and a number of my DW friends list are very geeky.  I'm glad this is in your areas of interest.

[disneydream06]

Double the life of batteries?
That is great news. :)
Hugs, Jon

[thewayne]

The Li-Ions, at least.  It's possible it could also work with other types, like Nicads.  I'll bet other scientists will be looking into it.

[disneydream06]

Good steps in the right direction. :)

[silveradept]

That is interesting. I wonder how many devices might be able to adapt themselves in software to a new methodology even if their hardware cables are still older and want to deliver the constant charge and voltage. If not, then I wonder where the charging circuitry is going to be implemented, whether it's in the cables or in the devices that are managing the batteries. I can't quite see the batteries themselves adopting circuitry like that.

[thewayne]

It seems to me that the intelligence and control is more in the charger, though some battery packs are becoming more intelligent and interacting with the chargers.  Hard to say how this will go.  And, of course, by making the battery pack more interactive with the charger you achieve more lock-in: "but it's in the best interest for the buyer!"

[silveradept]

I also wonder what the ramifications may be for situations where the charger is disconnected in the middle of a pulse situation, or other regular operations of people doing what they usually do to devices.

[thewayne]

This is purely a guess, but since we're dealing with DC current, I don't think it would make a bit of difference.  It would just stop the current flow.  For example, the MacBook Pro that I'm typing this on right now.  The battery has some intelligence on it that communicates to the charger via a USB-C or MagSafe connection.  It's not like I have to sleep the computer before I disconnect it.