US 11,901,751 B2
Systems and methods for monitoring high charge levels in rechargeable batteries
Michael Jonathon Chen, Mountain View, CA (US); William Alan Saperstein, San Carlos, CA (US); James Robert Lim, Mountain View, CA (US); and David Wang, San Jose, CA (US)
Assigned to Google LLC, Mountain View, CA (US)
Filed by Google LLC, Mountain View, CA (US)
Filed on May 13, 2021, as Appl. No. 17/319,815.
Claims priority of provisional application 63/140,720, filed on Jan. 22, 2021.
Prior Publication US 2022/0239134 A1, Jul. 28, 2022
Int. Cl. H01M 10/44 (2006.01); H01M 10/46 (2006.01); H02J 7/00 (2006.01)
CPC H02J 7/00308 (2020.01) [H02J 7/0031 (2013.01); H02J 7/00302 (2020.01); H02J 7/007182 (2020.01)] 20 Claims
OG exemplary drawing
 
1. A battery charging method, comprising:
allocating an indexed sequence of bits in a buffer for tracking a battery charging state, the indexed sequence of bits having a first number of bits;
sampling a battery voltage of a rechargeable battery at a sampling rate;
for each sampled battery voltage:
comparing the battery voltage with a voltage threshold;
identifying a next bit position in the indexed sequence of bits; and
in accordance with a determination that a comparison result is true, adding a predefined first value to the next bit position in the indexed sequence of bits;
determining, in the indexed sequence of bits, a second number of bits that are filled with the predefined first value;
determining a ratio between the second number and the first number; and
in accordance with a determination that the ratio exceeds a threshold step-down ratio, stepping down a battery charge voltage to which the rechargeable battery is charged to a step-down voltage.