I came across an additional study published in March of this year that does testing on LFP batteries repeatedly charged at −10 °C so I wanted to update this thread. This study focused on overcharging and so they used relatively high cutoff voltages of 3.65V, 4.0V, 4.4V, and 4.8V. They used CC-CV charging and stopped charging when current got down to 0.02C. The results are inline with the previous studies I have cited in this thread. At a 0.2C charge current, there is little degradation. There is more degradation at 0.5C and more still at 1C. And unsurprisingly the higher charge voltages of 4.0V, 4.4V, and 4.8V also caused more degradation. At 0.2C even with the extreme voltages, the degradation is only a few percent after 50 cycles. Keep in mind that 4.8V per cell corresponds to charging a 12V battery using 4 series cells up to 19.2V!!
Here's the key chart:
Here's the key chart:
