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This statement, it turns out, is slightly glib as there is one Li-ion chemistry that can handle it: lithium titanate, it is usually called.
And just a note here: not all lithium titanate cells are so blessed.
One manufacturer who’s can is Nichicon with its SLBs or ‘small li-ion rechargeable batteries’.
And it has a document (section 2-3-2) to say that, although not guaranteed todo this, they typically can be charged at as low as -30°C if current is limited to 1C rate, capped at 2.8V and if charge is terminated at 0.05C. This is for the miniscule (7mm x 3mm dia) SLB03070LR35.
These cells have a lower nominal terminal voltage (2.4V) than more usual Li-ion cells, and therefore have less capacity, but who cares if that is the price to be paid for low-temperature charging ability if you need it.
With that unusual charge voltage (2.8V), picking a charging chip is not easy, but the same document includes a list of ICs that will work with the cells in section 3.3.
ADI’s LTC4079 caught my eye as a CV/CC charger whose output voltage (1.2 to 60V !!) and current (10 to 250mA) can be set, that has reverse blocking, and disconnects the measuring potentiometer when not in use for less vampire drain – although it does need a precision potentiometer.
And the IC includes battery temperature qualification, that might not been needed with these cells.
| Nichcon’s cells (SLB…) | 03070LR35 | 03090LR80 | 04255L040 | 08115L140 | 12400L151 |
|---|---|---|---|---|---|
| Nominal voltage | 2.4V | 2.4V | 2.4V | 2.4V | 2.4V |
| Voltage range | 2.8-1.8V | 2.8-1.8V | 2.8-1.8V | 2.8-1.8V | 2.8-1.8V |
| Max current (in or out) | 7mA | 16mA | 80mA | 280mA | 3A |
| Nominal capacity | 350μAh | 800μAh | 4mAh | 14mAh | 150mAh |
| Max ESR | 12Ω | 8Ω | 600mΩ | 240mΩ | 60mΩ |
| Range (°C) | -30 to +60 | -30 to +60 | -30 to +60 | -30 to +60 | -30 to +60 |
| Energy density | 17Wh/L | 25Wh/L | 30Wh/L | 58Wh/L | 73Wh/L |
| Weight | 120mg | 160mg | 750mg | 1.2g | 9.0g |
| Diameter (mm) | 3 | 3.3 | 4 | 8 | 12.5 |
| Height (mm) | 7 | 9 | 25.5 | 11.5 | 40 |
This is useful to know. Someone will need to check this, but I think that other lithium chemistries that recharge at negative temperatures are: lithium vanadium pentoxide (Panasonic VL series) and lithium thionyl chloride. If batteries are your thing, you probably want to have a good list of options.
Morning DB
Thanks for that
I didn’t know that there were secondary lithium thionyl chloride batteries – but I can now can see a research paper on them – interesting.
Re lithium vanadium pentoxide – I had not heard of those – looks like they are mA type batteries for back-up? And the Panasonic ones seem suitable for float-charging across -20 to +60C – useful 🙂
Well, ignore the thionyl chloride, then. I was dredging my memory and recalled wide operating range, and I thought I’d seen some in a secondary application recently, but my memory isn’t so good. The Panasonic VL series are nice, though.
I’ll back you up on the Panasonic VL series. Used them in several applications where they might sit in the back of a artic either on top of hot amplifiers or stuck in the snow overnight.