The Inside of a Battery
 

Since most don't know what the inside of a sub-c sized NiMH battery looks like, I decided to take some photos...

Since NiMH are dry cell batteries, there is no risk of having acid spill onto you while taking one apart. If you want to take apart a battery, make sure you have adult supervision. To remain safe, you want to wear a mask for your mouth and eye protection. The main derivative of this type of battery is nickel, which is considered semi-toxic. Nickel-metal-hydride also contains electrolyte that, in large amounts, can be hazardous. If ten or more of these types of batteries are collected, it is highly recommended that they be dropped off in a secure waste landfill, or possibly a recycling center. The nickel contained in this cell is very pure and can often be used after recycling.

interesting

did you just cut open an old cell or did something happen to it (burst, caught on fire, etc)?

I thought I'd also include a brief discription of how batteries/electricity work:

Electrons flow from the anode(the negative section of the battery) to the cathode(the positive end). When a circuit is made(connection between the anode and cathode), electrons are allowed to flow. Between these two connections, is a load is usually applied. In rc cars, the motor is the main load.

In order for a battery to operate, you need two different chemicals(Nickel Cadmium, Lithium Manganese, etc.). The production of electricty occurs when a chemical reaction takes place. This chemical reaction takes place when a circuit is made. After the batteries become depleted, this chemical reaction can usually be reversed. When batteries are charged, a certain amount of amperage is applied in the opposite direction. This flow of electrons in the opposite direction reverses the chemical reaction to its original state.

That was a working battery before it was cut open. In the last of the three pictures, I intentionally spread apart the layers to show how it was constructed.

Isn't the anode negative and the cathode positive? Pretty sure it is.

And isn't the electrolyte predominantly Potassium Hydroxide (KOH)? Which is a caustic, not an acid....

Just getting picky..... :)

yup, you're right, wrote too quickly there

Heres the reaction within a NiMH battery Source
Cathode (+): NiOOH + H2O + e- Ni(OH)2 + OH- (1)

Anode (-): (1/x) MHx + OH- (1/x) M + H2O + e- (2)

Overall: (1/x) MHx + NiOOH (1/x) M + Ni(OH)2 (3)

Oh man, this thread went from cool pictures of taken apart batteries, to some kind of acvanced chemistry class :confused:

Yeah....now stay tuned for the Electron flow vs. Hole flow debate. LMAO!!!

:lol: It wasn't meant to be chemistry class, just clarifying what he had said.

interesting.

could you explain to me why, when my car comes off the track and I discharge the cell pack (using an individual cell discharger) that cell num 6 (positive end of pack) has more runtime than the others? (in most cases, and with all my packs)

would it have anything to do with the power coming out of the negative pole? and the cell up the other end (positive pole) gets the least workout?

or am I just totally mad?

When a pack is cycled, it is exposed to a great amount of heat. As the heat builds up, the cells in the center of the pack tend to be the highest in temperature. After time this can cause the center cells to degrade at a faster rate than those on the outside.

It could also be that the discharger has a problem. Though most electrical components have very accurate measurements, some do not. If the resistance is off slightly, it can cause a varience in the discharge rate. That discharge tray may contain a diode that has slightly more resistance than the others.

I am not sure if there are any other causes for that.

...not the smartest thing to post...dont want 12 year old kids telling there dads that they were told its ok to rip a sub-c cell appart and end-up hospitalizing them selves because a metal shard cut their wrist...

good info though :)

Gezz, and I thought I was through with high school chemistry. Now the nightmares continue again. :weird: