I don't. I haven't used lithium cells. I'm just going by the IR numbers people report here, either from manufacturer or their own BMS or IR measurement device. I don't typically see anything like Peukert curves or other charts with voltage vs. current like we do for lead-acid. I expect IR figures to predict that (up to some point where chemistry of cell can't keep up with current, could be non-linear so you may be correct that 20kA is high.) It has been 280 Ah or so cells which had the 0.17 milliohm figure.
I saw one paper reporting 4000A from 100 Ah AGM. I assumed 16kA as a conservative figure for my 405 Ah bank, probably much less than 4x 100 Ah in parallel due to construction. We know lithium delivers higher current, can crank a car with a tiny jumpstart pack. People have welded contactors and blown fuses (including class T, I think) connecting an inverter to lithium batteries.
Of course, almost any battery included lead-acid could blow a class T fuse in some amount of time, if able to reach parts of its time/current trip curve. But blowing with inrush means the limited amp-seconds to charge capacitors have to occur in short enough time for the I^2 to overheat the fuse. My math said this might be feasible with the capacitor bank of some inverters - I think it was on the order of 100,000 uF.
On the other hand, my inverters are spec'd for up to 10,000 Ah battery bank, and no mention of precharge. For lead-acid & NiCd, wiring such a large bank might have more resistance and inductance (although it takes a lot of wire to reduce short circuit current much), but likely cells aren't optimized for low resistance high current.
That kind of inrush might not harm the inverter, but it might blow fuses. class-t fuses @ $40 a piece make a $20 precharge circuit worth it. Ehhh. I dunno. I think class-t fuses are usually pretty fast, but the inrush we are talking about is a small fraction of a second. I'm not convinced it...
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