Not saying that it necessarily is good for batteries to be heated, but the battery in my dark blue Prius had been standing in the car for several years in the Australian heat before I "resurrected" it! And apart from a single bad stick it is again in great shape!
Below is some of the relevant post at
https://www.endless-sphere.com/forum...189797#p189797
Quote:
Is this Battery as dead as a Dodo?
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This is going to be interesting!
The battery is very flat and many would assume that it cannot be restored at all.
But I believe that the NiMH technology will quite likely showcase it's resilience here once again; and that the battery might well be fine once I have pampered and cycled it a few times!
Here are the open voltages:
HP1: Open voltages (mV) : Entire 120s: 11230mV (yes, millivolt!)
HP2: 8060mV
Individual stick results, also all in mV:
1 1862
2 971
3 912
4 512
5 103
6 489
7 421
8 7
9 394
10 551
11 499
12 439
13 491
14 809
15 479
16 109
17 113
18 561
19 935
20 551
21 139mV
22 383mV
23 66mV
24 104mV
25 56mV
26 499
27 840
28 29
29 72
30 70
31 509
32 439
33 135
34 111
35 140
36 136
37 546
38 133
39 1415
40 2219
Best stick 2.2V, worst stick 0.007V - what do you think?
Who wants to hazard a guess if this battery is dead as a dodo, or not?
Very basic schematic of the NHW10 battery is attached.
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I wonder if the intended effect of the heating to 50degC for five days suggested in the patent may actually be accelerated self discharge to zero SOC.
The self discharge rate is very high at such high temperatures. It
might be the easiest way to discharge all cells and bottom balance them (if you have a temperature controlled oven for it and you are doing this to many batteries).
IIRC, the "Battery University" website recommends discharge of NiMH cells to 0.4V at low current to re-condition them. That's what I did with the 102s NiMH battery in my Vectrix, with good results. But for the 240s battery in the NHW10 Prius this is prohibitively tedious! Heating the cells
may be an easier way to achieve the same goal.
But I have not tested this!
Again, I'm not claiming it works, just speculating how it might work!
