Trying to understand hybrid battery better

i would change the title to 'trying to understand nexcell lithium battery'

or something that will attract the eye of nexcell users

 

"Internal resistance", in electronics, is a way of understanding the real-life behavior of a voltage source. In a battery, most of it comes from the chemistry and construction of the battery itself,

For any real-world voltage source, its voltage will decrease as you draw current from it. For engineering purposes, you can treat the real-world source as if it were an ideal voltage source (constant voltage unaffected by current) in series with a notional ideal resistor. Dividing the real-world voltage drop by the current gives you the resistance in ohms of that "resistor", and that's what an engineer means by "internal resistance".

In a Prius battery, of many modules linked together by bus bars, the "internal resistance" of the whole battery does end up including the actual resistance of the bus bars and bus-bar-to-post connections too.

Each per-block internal resistance figure calculated by the ECU includes the actual resistance of a couple bus bars and their bar-to-post connections, as well as the internal resistance of the two modules making up the block.

The skinny-wire voltage sense harness back to the ECU does not contribute to internal resistance, as it carries none of the discharge/charge current and only serves to sample voltages at several points along the current path.