New Alkaline Battery Leakage Testing - Page 1
Forum section: electronics / projects

author: EEVblog
author_rank: Unknown
timestamp: March 26, 2020, 07:55:07 am
content: So I'm going to rerun this experiment as clearly my 47ohm load last time didn't do the trick.From what I've been able to gather, the key seems to be almost complete discharge (it will build up the most pressure near the end of it's life) and then either a very light self discharge load (I think 10uA out to do it, very typical product "standby" load), or no load at all?Of course I can do multiple combinations.No series cells this time, just individual ones.And of course there would be debate over what 90% and 100% discharge is.Obviously can't put the light load on fresh batteries or it'll take years, so test acceleration is the key.Suggestions and comments invited!

author: mzzj
author_rank: Super Contributor
timestamp: March 26, 2020, 09:36:27 am
content: Only anecdotal evidence but these are the worst situations I have come up with:1. High current pulsed discharge (couple of 10 second 10A pulses)2. discharge to 0v and below, ie reverse polarity for weakest cell in equipment with several cells in series. Maybe like 10% mAh capacity with reverse polarity.

author: kallek
author_rank: Regular Contributor
timestamp: March 26, 2020, 10:07:34 am
content: This is interesting experiment. My suggestion is to drain some of the cells to about 1V per cell at 100mA current, and leave with light load. And drain some cells to 0.5V and leave with no load.

author: graybeard
author_rank: Frequent Contributor
timestamp: March 26, 2020, 07:34:46 pm
content: Put the batteries in a valuable piece of equipment since those are the ones that always seem to leak.Temperature cycle the batteries while partially drained and with a very light load. Most real devices see temperature cycles somtimes extreme.For example device left in a car could see temperature as high as 140ºF (60ºC) when left in a closed car in the sun summer, and below freezing -10ºF (-23ºC) in the winter. Uninsulated garages where many items are left also see temperature extremes. Even houses which have the heating and colling reduced when occupants are away can have large temperature excursions.Perhaps it is a combination of being discharged and or slowly discharging plus the expansion and contraction of temperature variations that causes the leaks.

author: graybeard
author_rank: Frequent Contributor
timestamp: March 26, 2020, 08:11:29 pm
content: Besides the temperature cycling you could run the test as several elevated temperatures. Most failure mechanisms are Arrhenius and have an associated activation energy.By running the test at several elevated temperatures you could both speed up the failures and measure the activation energy of failure mechanism.Over the years I have designed hardware for many reliability tests and most failure mechanisms are both temperature and current driven. Typically failures rates are exponentially dependent on Temperature (0.5 to 2 EV being a typical activation energy) and dependent on current density raised to a fixed exponent (typically 1 to4).Sometime humidity plays a role, but controlled humidity experiments are much more complicated to design. However since battery leakage does seem related to corrosion perhaps moisture is a factor.

author: tszaboo
author_rank: Super Contributor
timestamp: March 26, 2020, 10:48:40 pm
content: You should probably discharge it below 0V.Let me explain. If it is in a pack of 4 batteries, and one is weaker, than that gets to 0V first. Then the device still discharges them, than that weak cell goes into something called cell reversal. At least, thats what they call it with Li-ion batteries. I'm almost sure that this is causing the leak, and not the discharge.You know, what they always say...Dont turn it onDont mix batteries, use a fresh pack.

author: EEVblog
author_rank: Unknown
timestamp: March 27, 2020, 12:33:55 am
content: Quote from: NANDBlog on March 26, 2020, 10:48:40 pmI did that in the first video and several cells went reverse. None of them leaked.I think it's better to mostly discharge and then put a light load on it.

author: graybeard
author_rank: Frequent Contributor
timestamp: March 27, 2020, 05:27:25 am
content: An easy experiment to see if moisture exposure before use is an issue is to store some in a box with a slightly damp rad to increase the local humidity. Some of this moisture will diffuse into the batteries.Store others in a box with desiccant. Then treat them the same during the experiment and see if there is a difference between the two populations.

author: EEVblog
author_rank: Unknown
timestamp: March 27, 2020, 08:14:59 am
content: Quote from: graybeard on March 27, 2020, 05:27:25 amGood idea, but probably not for this video.

author: magic
author_rank: Super Contributor
timestamp: March 27, 2020, 08:23:10 am
content: Do it the other way around.Use only Duracells and try all of the combinations you posted plus whatever else people come up witheditMy personal experience: discharge them in a camera until the ESR rises enough that the camera shuts down, then leave them alone for months/years.

author: EEVblog
author_rank: Unknown
timestamp: March 27, 2020, 08:41:05 am
content: Quote from: magic on March 27, 2020, 08:23:10 amI have an old AA camera

author: eugenenine
author_rank: Frequent Contributor
timestamp: March 27, 2020, 11:58:02 am
content: Go to the store and buy one of the 30 packs of RayOVac, I have found brand new leaking cells in those packs before.

author: bill_c
author_rank: Regular Contributor
timestamp: March 27, 2020, 12:50:04 pm
content: Maybe its a mechanical problem. Get a plastic pipe that the cells will fit in that is say .5m or longer and place it over a hard surface (like concrete floor, not wood workbench). Drop a dummy cell in the tube, then the test cell, then another dummy cell, all + side up. This is kinda simulates dropping a flashlight or remote. If all goes wrong, it may weaken the seal just enough to leak when discharged in one of the above tests. The potassium hydroxide reacts with carbon dioxide in the air to form potassium carbonate (the white powder) so an enclosure that limits air movement but not sealed (similar to a remote or camera, but not a food storage container). I think a rapid pressure increase would compress the seal and make it less likely to leak, so I favor a slow discharge from start to end.

author: schmitt trigger
author_rank: Super Contributor
timestamp: March 27, 2020, 01:50:05 pm
content: Nowadays, most devices don't really turn off but only go into a very low current standby mode.However, years ago devices had a mechanical switch which would completely disconnect the batteries, and they would still leak.My suspicion is that leakage has to do with the quality of the battery's construction as well as the other variables.But as Graybeard mentioned, only half joking, to place batteries in an irreplaceable piece of equipment is the only sure way to cause a battery to leak.

author: graybeard
author_rank: Frequent Contributor
timestamp: March 27, 2020, 10:13:08 pm
content: Quote from: eugenenine on March 27, 2020, 11:58:02 amI had been happily using Rayovac for many years. However the last two batches I bought had many that turned into leakers. Rayovac is now made by the same corporation that makes Enigizer.

author: Prehistoricman
author_rank: Regular Contributor
timestamp: March 27, 2020, 10:24:29 pm
content: More anecdotes:I've found that smoke detector batteries have a high chance of leaking/exploding. They must have a light load to get the lifetime high.

author: Electro Detective
author_rank: Super Contributor
timestamp: March 27, 2020, 10:52:56 pm
content: Quote from: graybeard on March 26, 2020, 07:34:46 pmYou can bet on thatDJ may have to choose an expensive or irreplaceable 'sacrifice'if the current testing isn't going anywhere

author: graybeard
author_rank: Frequent Contributor
timestamp: March 28, 2020, 07:10:40 am
content: From the Energizer publication:Alkaline Manganese Dioxide Handbook and Application ManualOn page 13:Do store batteries in a cool, dry place at normal room temperature. Remove batteries from devices that will be stored for extended periods.-- this suggests that moisture intrusion and elevated temperatures is an issue.On page 14:Don’t mix old and new batteries, or mix different types or makes of batteries. This can cause rupture or leakage, resulting in personal injury or property damage-- this suggests that to get them to leak you should mix batteries in different states of discharge.From this Duracell publication:Alkaline-Manganese DioxideOn page 11 section 7.1:Batteries should be stored at temperatures between 50°F (10°C) and 77°F (25°C), with relative humidity not exceeding 65 percent. Refrigeration of alkaline batteries is not necessary because of their very good capacity retention. Excessive temperature cycling and storage at temperatures greater than 77°F (25°C)should be avoided to maximize shelf life.-- this suggests the both extreme temperatures and high humidity should be avoided. Although this is not stated as being a cause of leakage it certainly could be a contributing factor.Duracell publication:Alkaline Manganese Dioxide Battery Product Safety, Transportation and DisposalThis also suggest limiting temperature and humidity.This in an interesting paper fromUniversity of Babylon in Hillah, Iraq:ALKALINE-MANGANESE DIOXIDE BATTERIES-- this is a good summary of cell sizes, construction methods and materialsThis paper on a US DOE web site describes in detail the chemical mechanism of battery leakage:Understanding the Dynamics of Primary Zn-Mn02Alkaline Battery Gassing with Operando Visualization and Pressure Cells-- "It is shown that steep concentration gradients emerge during the cell discharge through a redox electrolyte mechanism, leading to the formation of high surface areaZn deposits that experience rapid corrosion when the cell rests to its open circuit voltage. Such corrosion is paired with the release of hydrogen and high cell pressure" —eventually leading to cell rupture" -- to me the paper suggests that fast high current discharge followed an open circuit may be best way to get leakage. It also has some interesting electron microscope photos.

author: magic
author_rank: Super Contributor
timestamp: March 28, 2020, 07:59:36 am
content: Quote from: graybeard on March 28, 2020, 07:10:40 amGood find. It seems that what it takes is a fast discharge and then open circuit.Not sure if deep discharge increases chances of leaking or if it's enough to just get to the point of rising ESR as formation of "black Zn" (blamed for leaking) appears to be correlated with "cell passivation" (blamed for ESR).

author: mzzj
author_rank: Super Contributor
timestamp: March 28, 2020, 08:08:37 am
content: I was sorting out some random batteries I had lying around benches by measuring the short-circuit current of them and found out that every one of them had leaked 6mo later. (but most were chinese Ikea batteries)I replace probably 200 AA batteries per year at work and the old ones go to collection bin. Last time I was emptying it 99% of the batteries that had been sitting there probably up to 3 years after use were still looking ok.

author: magic
author_rank: Super Contributor
timestamp: March 28, 2020, 08:14:20 am
content: By the way, it's a very different story with NiMH.I have seen a few NiMH cells which leaked simply from lying unused for many years. One pair was pulled out of a cordless mouse, so it has never seen a fast discharges in its entire life, another I'm not even sure if it had ever been used at all.

author: EEVblog
author_rank: Unknown
timestamp: March 28, 2020, 08:30:40 am
content: Quote from: graybeard on March 28, 2020, 07:10:40 amThanks. I might give them a final 2A burst or something, they are currently on a 24hr 100mA discharge, as per this video:

author: Electro Detective
author_rank: Super Contributor
timestamp: March 28, 2020, 08:55:47 am
content: Not sure if mentioned before, but what about the metal to metal differences between the battery and device terminals ?Scenario:air tight battery enclosure,flat batteries,metal to different metal thermocoupling effect ..or whatever it's calledresulting in internal expanding gasses in the battery with nowhere to gosealings compromised (kaput/knackered)SPLAT n SPEW= C virus bankrupted Fluke or Brymen owners not happy campers

author: graybeard
author_rank: Frequent Contributor
timestamp: March 28, 2020, 03:39:59 pm
content: This is figure 6 fromUnderstanding the Dynamics of Primary Zn-Mn02Alkaline Battery Gassing with Operando Visualization and Pressure CellsIt shows both the recovery of voltage and the build-up of internal pressure when the battery is open-circuited from a hard discharge.Atmospheric pressure is 14.7 psi, so 0 psig=14.7psi absolute. So the normal hydrogen partial pressure is approximately 3 atmospheres. So the peak partial pressure shown of 193 psig is 13.1 atmospheres.For comparison, for submersion in water pressure increases one atmosphere for every 33 feet (10m). Thus the peak partial pressure of H inside the battery equivalent to the water pressure at a depth of 400 feet (131m). Based on the graph the pressure was still increasing at the end of the measurement so there is no reason to think it does increase to a higher value than shown. --> No wonder they leak!

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: March 28, 2020, 08:30:48 pm
content: IMO, running down and leaving with a low load is the worst. I used to have an answering machine with a terrible design- when the batteries got low it would light an LED to let you know!The thing was the worst battery leakage device I've ever seen.

author: Electro Detective
author_rank: Super Contributor
timestamp: March 29, 2020, 09:58:29 pm
content: Quote from: Conrad Hoffman on March 28, 2020, 08:30:48 pmbut that was back in the day when batteries were less of a leakage coin toss, right?With most batteries today, that same LED will let you know that not only are the batteries low,it may also be time to pull them out and clean up the disaster,rescue the terminals if not too badand pray the muck monster didn't crawl along to the PCB for a snack..and let's not forget those mysteriousacid holes that magically appear days later on favorite* work/hobby garments* terminally BO'dand overdue for the washing machine, bin, burial, fire or phasor shoti.e. don't be doing it with an Armani suit on waiting for the limo to rock up, or a prized EEVblog T-Shirt that's no longer available