Picture of a disassembled Duracell 9v battery. Below the terminal assembly is a clear plastic case where you can see six sets of stacked rectangular terminals and fillings.
I had an old 12v power tool battery die, so I took it apart to find 8 generic AA rechargeables wired together. I suspect lots of batteries are multiples of 1.5v (9/12/18) because they’re just stacked smaller cells that are already mass produced.
Battery chemistry produces fixed voltages depending on what you use. It depends on where the active components sit on the electronegativity table.
The typical ones are:
Zinc-carbon and alkaline - 1.5 volts per cell.
Lead acid - 2 volts
Nickel Cadmium - 1.2 volts
Nickel Metal Hydride - 1.4 ish.
All the Lithium ion combos - 3.4 to 3.7 volts.
Lipo is something like 3.4ish to 4.2v
The voltage range depends a lot on cell construction, temperature, load or charge rate, and chemical mix.
For example “lead acid” batteries with lead and sulphuric acid have a cell chemistry voltage of 2.05 volts but their nominal range is 1.8 to 2.4 volts per cell. Translating that to a 6 cell “12 volt” car battery gives you a range of 10.8 to 14.8 volts.
Yeah they had nicad or nimh batteries donated together to create the battery pack. I had an old shaver that was the same way. Laptops with replaceable batteries do the same things
Current power tools still do this, but with 18650 lithium cells, or some larger variant. But now the trendy thing in power tool batteries are the pouch cells, like the kind found in cell phones and slim laptops. I gotta they’re more energy dense, since there’s less of an air gap between cells.
There didn’t used to be efficient ways to convert DC/DC voltages up in electronics (you could drop it, though also not very efficiently), but nowadays there are technologies to do that and hundreds of choices of integrated chips that do most of the work along with a inductor and a diode (these being the very minimal set of parts) with about 90% efficiency, so stuff that needed higher voltages and had to use multi-cell batteries for it in the past, now can be done with batteries that output much lower voltages along with one of these voltage converters (called “boost converters”).
(For those in the know, yeah there was already something before for lower currents called voltage pumps, using only capacitors, but those thongs couldn’t handle higher currents).
Anyways, all this to say that manufacturers can now choose to use smaller and simpler batteries for the equipment they make and convert voltage up in circuitr cheaply and with minimal losses, hence you’re much more likelly to see that when it makes economical sense for them (for example, by being able to use the more common battery types rather that having to have unique custom batteries, as the latter are more expensive since they do not get the same savings from the economies of scale of mass production).
Some are also 6x little tiny aaaa batteries
I actually took it apart hoping to find the AAAAs.
They still have those, just depends on the brand.
Cheap low-capacity 9V batteries are still 6 AAAA cells. The flat cells allow higher capacity in the same space, so you find them in the batteries that advertise themselves as long-lasting.
Disapointingly, it came wrapped in a branded metal case that you have to pry apart to see the cool layers.
They need to make transparent ones as a special edition xd
They used to think that sort of thing was cool in the 90s.
They were right. I stand by this claim.
I had one of those in my bedroom growing up!
A friend of mine had one as a teenager and then brought it with him to his dorm room after high school. We called it Pavlov because it had to be answered when it rang.
I saw one of these at Target the other day in the $5-and-below section. Except it wasn’t a full phone, it was a nostalgia grab designed to be a wired “headset” for a cell phone with a headphone jack.
what do you mean “used to”?
The metal shell is part of the protection.
Who needs protection when you have cool lookin batteries?
Jokes aside, maybe a print of how the insides look would be cool, too. Like the phone cases from that recent JerryRigs drama.
purple or go fuck yourself.
Better use of space - they used to be just six coin cells with a load of empty space for a wire to connect the top connector to bottom of the stack
I used to take apart 9v batteries to get AAAA cells for my laser pointer
Those super expensive rechargeable batteries they sell for cordless power tools have smaller cylindrical batteries inside, wired together.
The Torque Test Channel on YouTube took some apart for their insane Dewalt backpack battery modification video. It’s a fun watch.
Let’s play is it cake?
Those sentient cakes, man. They really keep you guessing.
I SWEAR, I’M A PERSON!!!
The voltage of batteries in series adds and 1.5V * 6 = 9V, that’s why.
Btw, why do the flat ones (4.5V i think?? use 3 round batteries instead of rectangulars? They could have more capacity due to less space wasted.
It’s cheaper, especially for such a relatively uncommon battery type.
Our lives are a lie!
