Help required to understand Prius Battery

just a guess, but it looks like you need to replace block 8 and rebalance the pack.i don't think there is such a thing as the complete battery gone.

 

In short, you need a replacement pack. New is ideal.

Block 8 is your main issue, but the blocks around #8 are not in great shape either. I am surprised since your mileage is not very high. Is your hybrid battery cooling fan working properly?

 

If you are a do-it-yourself type, you might want to message @2k1Toaster to research the cost of his pack of new cells. I know he has sold some outside the US. His website link is in my signature.
His pack may be less expensive than a new Toyota battery pack.

 

Look at this thread to understand the 14 bars in your graph, 3G Hybrid Battery Voltage? | PriusChat. What you want is to have all 14 bars at the same voltage near 15.0 volts. I believe you can explain the shape of your graph as such: as you move from the outside toward the middle, you are moving from the outside of the pack to the middle and the cooling is less efficient in the middle of the pack. Heat is degrading the packs in the middle giving the lower voltage readings. It's almost a perfect gradient as you move from the outside to the middle on both sides. I believe you can buy individual battery modules and replace the ones in the center of your pack giving you the lowest readings. Search the forum (or YouTube) for advice on re-conditioning battery packs.

 

You could replace modules but ideally you should get the same generation modules and balance them to match the other ones. Companies selling "reconditioned" packs do not take the time needed to proper balance and recondition a pack.

I know Hybrid Automotive sells used modules and the Prolong reconditioning system. That may be the best way to lengthen the life of an old pack, but it is still an old pack that will fail sooner than a new pack or a pack with the new cylindrical cells I referenced earlier.

 

Greetings... Because you're in Pakistan, the cost of replacing the entire pack, once you account for shipping, customs, taxes, etc. is going to be a year's salary or more. Your best bet is to pull the hybrid pack out and replace individual modules with used replacements which will likely cost less than 7 thousand Ruppee. In the meantime don't drive the vehicle until the repairs have been made... As you can see in the graph, the failed/failing module is creating too much heat that is likely damaging neighboring modules.

If you have some skills working with batteries you can pull and clean connectors (bus bars) off the modules, then test voltage of each of the 28 modules, as well as test how much the voltage of each module drops after 2 minutes of being hooked up to the car's head light bulb. Also measuring internal resistance provides good data. Once you have all that data, you'll know which modules are the highest priority to replace.

While waiting for the replacement battery modules you can recondition battery modules you intend to keep using to improve it's overall performance by using two headlamp bulbs to drain each module down to 6.5 volts, then recharge each module using a NiMh smart battery charger that they sell for charging RC drones & toy cars to charge each module back up. Next step is to discharge each module again, this time down to 6 volts, then recharge... Then a 3rd time to below 6 volts... Be careful on the last one. When these modules drop below 6 they start to fall off a cliff and if they discharge to zero the polarity will reverse and you'll have to order more modules.

Finally, test your replacement modules to make sure they have similar data under a load test and internal resistance, then put it all back together and pray that everything works and hopefully it will. Because you're in Pakistan, the hardest part is going to be finding quality replacement modules from reputable sellers who know how to successfully ship them there.