History
Commercially working batteries had become widely used after their invention in the early 19th century, but they had many drawbacks. The electrolyte was a liquid acid which meant the casing was usually glass, making them relatively delicate, heavy and hazardous if they broke or spilled.
They were robust enough to work on fairly stable platforms such as rail wagons, but generally needed a static location.
In 1886, Carl Gassner made a breakthrough and patented the zinc-carbon dry cell. This chemistry allowed the liquid electrolyte to be mixed with a gelling agent (originally plaster of Paris) to make a paste. It wasn’t truly dry, but enough for the battery to be able to operate at any angle for any length of time.
Furthermore, it could be made small enough to fit in the hand and so opened the door to truly portable appliances such as flashlights and portable radios. It would dominate the domestic battery market for nearly half a century.
The elements are as follows:
- An anode (negative) – zinc metal often forming the battery case and negative terminal.
- A cathode (positive) – a carbon rod in the center of the battery, surrounded by manganese dioxide and connected to the positive terminal.
- A separator – often simply starch coated paper.
- Electrolyte – ammonium chloride paste.
- A gasket to separate the positive terminal from the negatively charged case.
In some models the zinc metal case is covered by a plastic shell. This is because it is very close to the positive terminal at the top end of the battery and accidental shorting when placed in a metal container or next to other batteries is possible.
Zinc-carbon and zinc-chloride
As technology progressed and manufacturing processes were refined, it was possible to use purer zinc and manganese, which led to the zinc-chloride version of the battery. These last up to four times longer than the basic zinc-carbon battery and offer a steadier voltage during discharge.
They are usually marked by manufacturers as heavy-duty, extra-heavy-duty, or super-heavy-duty. Both zinc-carbon and zinc-chloride batteries remain in production to this day. For more on the difference between the two see Zinc-carbon versus zinc-chloride.
Zinc based battery sizes
The most commonly seen zinc based batteries are now zinc-chloride (just look for the ‘heavy duty’ branding), but from time to time you may spot an original zinc-carbon. They are usually offered in the following sizes:
- D
- C
- AA
- AAA
- 9V
Post time: Apr-04-2023
