Li-Ion Battery Integration#
Lithium-ion cells pack more energy per gram than any other rechargeable chemistry commonly available to embedded designers, but they demand careful handling. Overcharging by even 100mV accelerates electrolyte decomposition. Deep discharge below the cutoff voltage causes irreversible copper dissolution on the anode. Excessive current draw generates internal heat that degrades capacity and, in extreme cases, leads to thermal runaway. Every Li-Ion-powered design needs a charging controller that follows the correct CC/CV profile, a protection circuit that enforces hard voltage and current limits, and — for any product that reports battery level — a fuel gauging strategy that accounts for the nonlinear relationship between open-circuit voltage and remaining capacity.
This section covers cell selection and ratings, charging IC configuration, battery protection circuits, and state-of-charge estimation — the four subsystems that sit between a raw lithium cell and a safely powered embedded device.
What This Section Covers#
- Cell Selection & Ratings — Chemistry types, form factors, C-ratings, voltage ranges, and temperature limits for choosing the right cell.
- Charging ICs & Profiles — TP4056, MCP73831, BQ24072 configuration — CC/CV charging profiles, charge termination, and thermal regulation.
- Protection Circuits & PCMs — DW01/FS312 protection ICs, undervoltage lockout, overcurrent and short-circuit protection architectures.
- Fuel Gauging & SOC — Coulomb counting, voltage-based SOC estimation, lookup tables, and firmware interfaces for battery level reporting.