# What is battery corrosion? **URL:** \ **Category:** Factual Questions\ **Created:** [August 5, 2013, 7:50pm UTC](https://boards.straightdope.com/t/what-is-battery-corrosion/665426 "2013-08-05T19:50:56Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Measure\_for\_Measure](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/measure_for_measure/32/557_2.png) [@Measure\_for\_Measure](https://boards.straightdope.com/u/Measure_for_Measure)\ **Post date:** [August 5, 2013, 7:50pm UTC](https://boards.straightdope.com/t/what-is-battery-corrosion/665426/1 "2013-08-05T19:50:56Z")
And why does it occur? I see it in automobile batteries, but I’ve also seen it with older carbon batteries and I think alkalines. Why hasn’t this problem gone away? I’m guessing this question is related to, “How do batteries work?” ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [August 5, 2013, 8:11pm UTC](https://boards.straightdope.com/t/what-is-battery-corrosion/665426/2 "2013-08-05T20:11:28Z")
For [car batteries:](https://en.wikipedia.org/wiki/Automotive_battery#Failure) > [@Wikipedia](#): > > The white powder sometimes found around the battery terminals is usually lead sulfate which is toxic by inhalation, ingestion and skin contact. The corrosion is caused by an imperfect seal between the plastic battery case and lead battery post allowing sulfuric acid to react with the lead battery posts. The corrosion process is also expedited by over charging. Corrosion can also be caused by factors such as salt water, dirt, heat, humidity, cracks in the battery casing or loose battery terminals. for [the batteries used in consumer electronics:](https://en.wikipedia.org/wiki/Alkaline_battery#Leaks) > [@Wikipedia](#): > > The reason for leaks is that as batteries discharge — either through usage or gradual self-discharge — the chemistry of the cells changes and some hydrogen gas is generated. This out-gassing increases pressure in the battery. Eventually, the excess pressure either ruptures the insulating seals at the end of the battery, or the outer metal canister, or both. In addition, as the battery ages, its steel outer canister may gradually corrode or rust, which can further contribute to containment failure. > > Once a leak has formed due to corrosion of the outer steel shell, potassium hydroxide absorbs carbon dioxide from the air to form a feathery crystalline structure of potassium carbonate that grows and spreads out from the battery over time, following along metal electrodes to circuit boards where it commences oxidation of copper tracks and other components, leading to permanent circuitry damage. ---
**Author:** ![Measure\_for\_Measure](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/measure_for_measure/32/557_2.png) [@Measure\_for\_Measure](https://boards.straightdope.com/u/Measure_for_Measure)\ **Post date:** [August 6, 2013, 4:35am UTC](https://boards.straightdope.com/t/what-is-battery-corrosion/665426/3 "2013-08-06T04:35:48Z")
Thanks Machine Elf. So why isn’t the problem solved? And how did they make it a milder problem over time? ---
**Author:** ![AaronX](https://avatars.discourse-cdn.com/v4/letter/a/7bcc69/32.png) [@AaronX](https://boards.straightdope.com/u/AaronX)\ **Post date:** [August 6, 2013, 10:00am UTC](https://boards.straightdope.com/t/what-is-battery-corrosion/665426/4 "2013-08-06T10:00:31Z")
I think batteries also corrode because some use the casing as an anode, i.e. it dissolves as the battery is drained. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [August 6, 2013, 11:46am UTC](https://boards.straightdope.com/t/what-is-battery-corrosion/665426/5 "2013-08-06T11:46:44Z")
> [@Measure\_for\_Measure](#): > > Thanks Machine Elf. So why isn’t the problem solved? And how did they make it a milder problem over time? Problems rarely get solved; they just get minimized. For car batteries, presumably battery manufacturing processes have gotten better over time so that the seal between lead terminal post and plastic case is more consistent. But If you want to absolutely solve the problem, be prepared to spend a lot of money for batteries. Likewise with batteries for consumer electronics: I expect the manufacturing has improved the reliability of the seal and the corrosion resistance of the case. ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [August 6, 2013, 2:08pm UTC](https://boards.straightdope.com/t/what-is-battery-corrosion/665426/6 "2013-08-06T14:08:25Z")
batteries are chemical reactions which consume some chemicals and produce others. involved in this is where these consumable chemicals (reactants) and produced chemicals (products) can be, often you want the reactants plentiful and available and the products moved out of the way. this is hard to do in a controlled confined situation, which makes batteries (the small dry cell) really a wonderment that they work as well as they do for as long as they do. ---
**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\ **Post date:** [August 6, 2013, 3:42pm UTC](https://boards.straightdope.com/t/what-is-battery-corrosion/665426/7 "2013-08-06T15:42:55Z")
As a side note: if you have a vehicle or other conveyance that sits for long periods without running, it’s a good idea to clean the terminals from time to time or you can have a starting problem. [Handy tool](http://www.harborfreight.com/battery-terminal-cleaner-94450.html) for that.