Shining a light on batteries

I’m very confused about all the different types of batteries and have so many questions—what do the different types mean? Are they all hazardous? Which batteries are recyclable and which aren’t? What about the wee round ones like those from my husband’s hearing aids that sometimes get sucked up into my vacuum cleaner?

And I know I’m not the only one who’s confused, as we get lots of people ringing up Nelson Environment Centre to ask what they can do with their batteries or popping in with buckets of batteries they have been saving up to recycle.  So, determined to make a better job of giving people the right advice, I set myself a goal to get to the bottom of the Great Battery Mystery.

Here’s what I found out.

Firstly, there are an awful lot of different types of batteries — AARGH! — Wikipedia lists 76 types! (And, for anyone who cares, the wee round ones are classed as “buttons” !)

But the important thing for the average person like me to know is that they all contain hazardous substances, e.g. lead, mercury, cadmium, zinc and lithium and, as our local councils’ websites advise, need to be disposed of correctly. Some are more hazardous than others, lead and mercury being especially harmful to health if they leach into waterways.

So what does correct disposal mean – recycling them? Our local councils do provide recycling for some batteries but not all. It appears that batteries fall into two main types: non-rechargeable and rechargeable batteries. Our councils recycle most rechargeable batteries and some non-rechargeable batteries.

Non-rechargeable (or ‘single-use’ batteries) are fully charged when you buy them; once they have used up their charge and finished working, they have to be disposed of. The commonest non-rechargeable batteries are alkaline batteries that depend upon the reaction between zinc and manganese dioxide.  Other common non-rechargeable batteries are zinc carbon and zinc chloride batteries. Alkaline batteries have a higher energy density and longer shelf-life when compared with zinc chloride or zinc-carbon batteries with the same voltage.

Rechargeable batteries on the other hand can be charged and recharged many times.  They are produced in many different shapes and sizes, ranging from button cells  to megawatt systems.

Several different combinations of electrode materials and electrolytes are used, including lead–acid (car batteries), nickel cadmium (NiCd), nickel metal hydride (NiMH), lithium ion (Li-ion), and lithium ion polymer (Li-ion polymer). The majority of lithium-ion batteries are recyclable and lithium is a valuable commodity. Which is a good point: lots of these substances are really valuable, like lead and mercury, so that’s another good reason to keep them out of landfill.

They’re worrisome things batteries  – especially when  kids can swallow them – must go check my carpets…!

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Sarah Langi is an opccasional contributor to Kiwiboomers. She has worked for Nelson Environment Centre for more than a decade now, delivering programmes in renewable energy, waste education, gardening and streamcare to schools and early childhood centres in Tasman and Nelson. Prior to that she worked as a technical editor for the Secretariat of the Pacific Community in New Caledonia, and as a fisheries scientist in Tonga, where she raised her two children. Her early career was spent as a primary school teacher for 12 years, in NZ and overseas. She has a BSC in Zoology from Victoria University and a BA Hons in Classics from University College London.