Great AA Alkaline Battery Test – Pt 4: Cell Physical Characteristics

After the rather interesting results in the previous section, I was curious as to who actually manufactured the cells for the lesser known brands, and whether that could be determined just by examining the physical characteristics of the cells.

Given the batch of cells, a clear place to look for physical commonalities is in the terminals of each cell. Photos of the top and bottom of each row are shown below.

A number of related cell families can be identified, but with many cells, it is not clear as to whether there are any relationships between different brands. To try and uncover more of this will require me to lose some skin as I spend all morning peeling back the shrink wrap of the cells to look at any markings underneath and the structure of the negative seal of the battery. Of course, we might not have a smoking gun that a particular cell is made by the same manufacturer as another, but we might get clues that they used the same manufacturing equipment or design which is a clue.

The Duracell Family

The most obvious “family” in the group is the Duracell family.

All of Duracell’s batteries use a “false” negative terminal which is a plate with two spot-welds onto the real battery casing. This arrangement, in the case of Duracell branded cells, has the Duracell lettering stamped into the plate. In the case of their Simply brand, and the Industrial brand, the plate is left clean.

The plate itself serves a purpose, as between the plate and the casing is the “seal” of the battery. A fibre washer (more like a cardboard ring) is placed in-between to soak up any expelled electrolyte and the plate diverts it towards the wrapping, increasing the path length for the electrolyte to provide some “leak resistance”.

Under the wrap, most Duracell batteries seem to have a two line ink-dot printed code. Because of these unique characteristics, if some other brand says they’re “manufactured by Duracell”, it’s highly unlikely to be the case that it’s happening, and it’s highly unlikely they’re using the same equipment if it doesn’t have the same characteristics.

The Energizer Family

The Energizer family is made in Singapore or USA, and all have a similar terminal base with three vent holes arranged in a triangular fashion. The exception is the Eveready Gold with a dimpled base and four vent holes, which I included, since it is likely to be part of the family as Energizer and Eveready are the “same company”, namely Energizer Holdings. The dimpled bottom on the Eveready Gold is (if I recall correctly) the same used in old Energizer cells, so maybe they’re just using the old equipment or stock to push them out.

It can’t be seen clearly in the image, but each bottom has a sort of “plastic” coating of some sort. I struggled to capture it in an image, but a translucent layer is seen that is a little like conformal coating, which is true of the Eveready Gold as well.

All cells, however, share a special Energizer trait of a welded on positive terminal plate, with three spot welds. Because of these unique characteristics, it’s not likely any other brand’s cells are made with the same equipment.

Their marking is a little more primitive – no text was found, but coloured permanent marker stripes on the cell which have “soaked” into the label adhesive.

The Varta Family

The two Varta cells from Germany are both quite obvious. They have a special terminal design which is unique to them.

The end-cap has three vent holes, and there is a white-translucent internal insulator.

Text codes in the form of three lines of four characters are printed somewhat illegibly onto the cell.

The FDK Corporation Family

FDK Corporation cells are easy to spot since they’re the only cells that seem to come out of Indonesia. The Fuji EnviroMax brand and the Fujitsu Alkaline G are both members of this family.

The members all have dark green leak-guard rings which have a circular notch cut out of the edge. This guard also serves to deflect any leaked electrolyte towards the wrapper, instead of the terminal.

The expired cell on the left has coloured marker indications, whereas the newer cells have two rows of printing – illegible first row on the second battery, X**D4 and what appears to be a time on the rightmost two.

The Kodak Family

The Kodak family is another two member family, characterized by their very lacklustre performance. It’s quite curious, especially given their photography heritage, that their cells are so poor at high load. Maybe it was their attempt to sabotage digital photography, or maybe it was just them “selling their brand” to others that didn’t know a good battery from a poor one.

Regardless, both cells features two vent holes on the terminal, a clear insulator and a black leak-guard ring.

The cells had difficult-to-read laser engraved text on them in two lines – an alphanumeric first line ending in a number, and a numeric second line, printed to be readable with the negative terminal to the left.

The Green-Ringed Group

Now, we are mostly left with purely Chinese batteries, and the only commonality I could find with a group of them was the presence of green leak-guard rings. I decided to unsleeve them all to see if there are any commonalities.

No surprises – they all had green rings! However, the shade of green is different for the RS Pro Alkaline which has a dark green ring. The other rings are roughly a similar shade. The Daiso, old IKEA, Activ Energy and GP Ultra Plus all have three vent holes, while the remaining ones have two. All use clear-looking insulators.

In terms of markings, the new IKEA, Toshiba Alkaline, Activ Energy and GP Ultra Plus all had laser etched engraving on the cell in the same sort of format and direction as the Kodak family. The font and positioning are subtly different, so it is hard to draw any conclusions but there might be some link in the manufacturing equipment?

RS Pro and the old IKEA batteries both had ink printing across the cell which soaked into the jacket.

The Unknowns

Now we get to the odds and ends where there isn’t any clear commonalities, so lets just tear the jackets off anyway.

The Pairdeer has a red leak guard ring, and the other cells do not have this feature. The crimp on the Panasonic cell is quite deep, and as it turns out, it has a red resin applied to seal the bottom, so it probably has no need for a ring. The two Winmax cells and the Coles Advance cell all have laser etched printing in the same direction and similar format to the Kodak family and other cells noted above.

In terms of negative terminals, it seems the number of vent holes is two for Pairdeer, Daiso, Naccon, Winmax Super Alkaline and three for Winmax Extra Alkaline and Coles Advance+. The Panasonic had four, and what appeared to be a protective plastic overwrap under the first layer of the label. In the case of the Daiso cell, the negative terminal protruded out from the casing more than the others, suggesting there’s something special about it.

Finally, the last group of cells was the following …

The PowerOne cell has laser etched text just like the Kodak family and above mentioned cells, however, the Chevron has a laser etched text that is in three lines across the cell. Eclipse and Performer both have different ink-printed text across the cell.

Looking at the end, none of these cells feature any leak-guards. Most of them have two vents and a clear insulator, although the size and arrangement of the vents are different.

Conclusion

The characteristics of certain manufacturer’s cells has been documented in this post, although identification of the lesser known brands was somewhat uncertain.

It’s been a rather long and comprehensive investigation – one that got a little out of hand but also in a rather spectacular way. At least, with this posting, I can close off the series and deliver it “whole”. If I wasn’t so lucky as to get the B&K Precision Model 8600, this probably would have never happened, and that’s probably a bad thing.

In all, the B&K Precision Model 8600 DC Electronic Load was a reliable partner throughout all of these tests, never faultering. The included software did have a few bugs which I reported and got fixed, but was sufficiently good that I didn’t really need to code any software of my own.

The batteries themselves … maybe I’d be happy if I didn’t see another battery for the next few months.


Endnote: You may have noticed a slight image discrepancy with the “green ringed” group and the “unknowns” group. This is because I had prepared a front facing shot with all the cells de-sleeved. Sadly, due to a glitch in the camera, the file was never written to card successfully. The same happened moments later with an image of the cell negative terminals. The number for which the file was to have been allocated was missing on the card, and undeletion/hex edit utilities could not uncover any trace of the file on the card. As a result, I had to grab the second cell of each brand, de-sleeve them again, and reproduce the front-facing/negative terminal shots which produces a slight positioning discrepancy. The order was maintained, however.

About lui_gough

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2 Responses to Great AA Alkaline Battery Test – Pt 4: Cell Physical Characteristics

  1. Mark Hanrahan says:

    Fantastic job on the Great AA Alkaline Battery Test, really appreciated. I go through a lot of AA’s at work, and buy a single box of 576 at a time. Maybe the final test could have been which depleted batteries leak the most. There’s been a lot of equipment at my work that has suffered damage from leaked batteries.

    • lui_gough says:

      I definitely concur on the leakage issue, but alas it’s actually more difficult than it seems because it’s likely to be influenced by cell design, protective features (e.g. washers, guard rings, sealants), how far the cell was discharged/the resulting gas buildup within, the temperature it’s stored at, any temperature swings, and the length of time (in addition to the usual seal to seal variance). As someone who has also had the annoyance of needing to fix crusty battery terminals, it’s a scourge we really want to get away from if at all possible, so remembering to remove the batteries prior to prolonged storage and making an effort to make sure the device’s switch is set to off before storage will go a way to helping with that.

      Low self discharge Ni-MH cells are typically built better and leak instead from the positive terminal in case of overcharge or long term overdischarge. They’ve generally treated my equipment better, but alas, not suitable in all circumstances owing to the additional need to charge them up, not lose them, not working as consistently in the cold, false battery-low indications, etc.

      – Gough

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