Need formulas for the dis/charge of batteries

[Abhinavpsingh]

Been asked to write a four page introduction to an Extended Experimental Investigation. The topic is investigating the discharge rate of batteries as a function of temperature. Need some help

[Thread moved to the schoolwork forums by the Mentors]

 

[BvU]

Hello Abhinavpsingh, $\qquad$ $\qquad$ !

Here at PF we definitely value some initiative from thread posters, and for homework like this it's even mandatory that you post your own attempt -- or else we are not even allowed to assist. So give us an excuse to help you ! Write down a plan !

 

[Abhinavpsingh]

Well it all has to be related to the topic and be more on the physics side rather than the chemical processes.
I have started with What is a battery and gone into a basic history. I have the mentioned Volta and also the Baghdad battery. Next I have briefly highlighted different types of batteries, (primary and secondary). I plan on going into factors impacting battery performance. Then I will talk about the Ohm's law circle of formulae. I then plan to go more in depth into how batteries discharge and then the impact of temperature. What I need help with is linking more formulas to my investigation.

 

[berkeman]

Welcome to the PF @Abhinavpsingh

Have you looked through the datasheet curves at the battery manufacturers' websites? They won't be giving any formulas probably, but any formulas that you do find would have to match up with that empirical data. You may be able to find some research papers on battery chemistry that will help you find some quantitative formulas behind this empirical data.

http://www.ti.com/lit/an/snva533/snva533.pdf
https://batteryuniversity.com/learn/article/how_to_measure_state_of_charge
https://www.powerstream.com/AA-tests.htm
https://html.scirp.org/file/80512x5.png

 

[anorlunda]

In addition to what @berkeman gave you, I would like to ask that you clarify your question.

Some batteries loose their charge just sitting on the shelf, and that can be influenced by temperature. That is a different question than how they discharge when supplying a load. That can also be influenced by temperature. Which of those two are you asking about?

 

[Abhinavpsingh]

Thank you @anorlunda
As this is being tested in a classroom setting, with a limited time frame, we are using a resistor and possibly a bulb to expedite the process. To power the circuit, we are using a 1.5V AA battery and measuring volts and amps via a multimeter

 

[anorlunda]

Thank you @anorlunda
As this is being tested in a classroom setting, with a limited time frame, we are using a resistor and possibly a bulb to expedite the process. To power the circuit, we are using a 1.5V AA battery and measuring volts and amps via a multimeter

OK. In that case, the curves provided by @berkeman in #4 should provide your answer.

Be careful that the temperature is the battery temperature, not the room temperature. As you discharge the battery through a resistor, the battery may warm up.