Overheating AA batteries

oops..my mistake ..it looks like Maxell amd Ikea (made in Germany) alkaline batteries are all the same..a positive side casing. When the hell did they stop making the old negative zinc sides? Only with Alkalines? What a PITA! My apologies.

BTW: Ikea batteries come from Varta. Better price than original Varta labeled and the technical performance is good. Duracell is better - even useable as AccuCell.

"bart" schrieb im Newsbeitrag news: snipped-for-privacy@4ax.com...

I've seen many Alkaline batteries with the outside casing connected to the 'tit' on top as the positive and the bottom flat connector was insulated from the body of the battery. alkaline batteries have different chemistry from carbon zinc resulting in an inverted construction. This may actually be the norm, but in the larger sizes the plastic outer wrap hides the details. Just looked at a DuraCell "D" and it is of the inverted construction, but the insulation of the battery bottom (-) terminal from the case of the battery is hidden under the plastic wrapping.

Since it's the cathode that gets eaten in whichever reaction is used for the battery type, it might make sense to have the anode as the case.

I could have done with this 25 years ago when I got sent abroad for work for three of months and came back to find that the transistor radio batteries had leaked all over one of my (expensive) loudspeakers :-(

Mark Rand RTFM

Positive can/case is standard alkaline cell construction. The correct question would be "has anyone ever seen a negative cased alkaline cell?"

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Sorry, but I JUST have to ask, Are you the Bob May who was on that TV show ( in that "suit") in the late 1960's??

Bob May wrote:

According to Bob May :

Most did -- but the zinc/carbon individual cells are relatively rare now. An example of the zinc-carbon ones without a negative case are the ones which were used to make high voltage batteries (even the 9V ones) were a wax ring (shaped sort of like a tire) with a zinc plate at one end and carbon at the other, with the sal-ammoniac (IIRC) in between. All of the wax rings were joined end to end by melting the wax, and this connected all the cells in series.

The "little button on the top" was a metal cap over the end of the central carbon rod which was the actual positive terminal.

However, the Alkaline cells use a different chemistry (I'm not sure of the details -- but it could be looked up), and the positive terminal makes the case -- which requires a strange form factor to deal with all the equipment designed to orient the button properly as a positive terminal. A standard flashlight would not care, but most electronic stuff powered by batteries does care, which is why they continue to shape things so the button is positive, even if it is connected to the case. The common coin cells are different, because there were never any of those with the button as positive.

Enjoy, DoN.

Chemistry lesson for the day:

Be careful what you call the cathode and what you call the anode. Oxidation ALWAYS occurs at the Anode, and reduction always occurs at the cathode. The oxidation process results in a chemical losing electrons, and the reduction process results in a chemical gaining electrons. (Mnemonics: "oxidation" and "anode" both start with vowels; "reduction" and "cathode" both start with consonants. "LEO sez GER": Loss of Electrons is Oxidation. Gain of Electrons is Reduction.) In a cell delivering power, the ANODE is the NEGATIVE terminal--the electrons given up in the oxidation chemical reaction come out there. If you re-charge the cell, the roles of anode and cathode are reversed. You feed electrons into the negative terminal, and (with luck) cause a reduction reaction where the chemical at that pole picks up the electrons and is converted back to what it was when the battery was freshly charged.

Cheers, Tom

Mark Rand wrote:

Guilty as charged (groan). It's just like my account with the bank where debits remove money instead of adding money like they should do :-)

Mark Rand RTFM