Hi everyone,
Just wondering is there any accelerated ways to test battery life cycle? Suppose that I need to test a battery with 500 rechargeable cycles, each discharge-recharge cycle need a few hours, then I would need a year to test its life cycle, even with automated battery tester.
I would like to shorten the testing time, but still be able to assess the battery's quality in terms of life cycle.
Any idea is appreciated. Thanks in advance.

 

Hi everyone,
Just wondering is there any accelerated ways to test battery life cycle? Suppose that I need to test a battery with 500 rechargeable cycles, each discharge-recharge cycle need a few hours, then I would need a year to test its life cycle, even with automated battery tester.
I would like to shorten the testing time, but still be able to assess the battery's quality in terms of life cycle.
Any idea is appreciated. Thanks in advance.

Very generally, every 10°C higher temp for the testing cycle, you can cut the number of testing cycles in half. That assumes you know the temp profile of the entire battery very accurately.

 

Thanks for your answer. But what temp profile are you inferring? Usually I only see capacity vs cycle number at 25 degree C in battery's specs.

 

Thanks for your answer. But what temp profile are you inferring? Usually I only see capacity vs cycle number at 25 degree C in battery's specs.

Yes, assuming the battery doesn't see significant self-heating during charge or discharge.
If the spec sheet of the battery doesn't measure battery temp but only ambient temp, then the battery may be running at 40°C during that testing cycle. Using a +10°C cycle would require the battery run at 50°C in a 35°C ambient environment.

If you are only trying to run 2x (+10°C) your battery might run naturally at 10°C higher. But, at higher temps, things don't follow rules so well for some reason and errors are propagated from ideal.

 

RE: Powergui
Sorry for leading You off Your theme, but do You are working in the battery industry??
Probably You may give me a recommendations for choosing the battery (accu) what is capable to survive a 30 years life-span if correctly and regularly recharged?? Simply it is intended to be eaten off by large animal and must serve there inside animal as much as animal lives, there is no way how to get it out and shift to the new-one.
Best known by me is ca 5 years - absolutely too short.
Supercaps - no any knowledge on life expectancy and degrading, and big doubt even up to first 5 years.
LiFePo- okay about 60 000 recharge cycles expectancy, but 5...7 years are somewhat near the outer boarder.
Japanese last year patented `ultra-life` silver base accu - still is not in the production and they obeyed only for 10 years.

 

There are primary cells that will run a smoke alarm for 10 years.
How is this battery going be recharged inside the animal?

 

There are primary cells that will run a smoke alarm for 10 years.
How is this battery going be recharged inside the animal?

Wireless charging, of course.
1) The real question is, how do you get the animal to stand next to the charging station for a few hours.
2) how do you get an animal to swallow a 12 kg AGM battery.

 

Battery is something rather 0,1 A*h or slightly bigger, thus we speak about miligrams not a kilograms. And swallowing is veterinary thing what is long ago solved. And animal has a habit to stay at least a half day or longer at the same place. And there is only one problem, why the boluss will not excreted out, even this problem is solved long ago - it must be heavy enough.
Thus, the problem is to name the material or in best case the producer which can warranty the longevity.
There I looked some datasheets form AGM v.s. gel batteries - max max 5 years and 1000 discharge cycles. Any Lithium-Ferrum-Phosphorus so much used in veghicle industry gives 60 000 cycles and the same 5...7 years, and this is sure not enough.

 

Doing accelerated testing requires you to do something that stresses the battery, but doesn't change the type of failure -- just makes it happen faster. For semiconductors, higher temperatures work quite predictably -- there's a formula for how much a temperature increase affects mean time to failure(which ius what you're testing).

So, you need to know what will do that for batteries. Battery manufacurers can probably tell you how to do it -- they probably have done this type of testing, but they might not share the results with you.

The other thing that you can do is test several batteries at a time -- in the same stress conditions. This is called reliability prediction. You test to see how many failures you get over time. Since you have multiple units, you can often get a good idea of failure rate a lot quicker. It's a statisitcal approach. If you google reliability prediction, you can probably find some good info.

Good Luck,
hj