Li-Ion Battery Integration on Embedded Systems Development

Cell Selection & Ratings

Mon, 01 Jan 0001 00:00:00 +0000

Cell Selection & Ratings#

Selecting a lithium-ion cell for an embedded project involves balancing energy density, discharge capability, physical size, and safety margins. The datasheet numbers — nominal voltage, capacity in milliamp-hours, maximum discharge current — only tell part of the story. Real-world performance depends on temperature, age, internal resistance, and how closely the system’s load profile matches the cell’s design envelope. A cell that performs well on a bench at 25 degrees C may sag below the regulator’s dropout voltage in a cold enclosure, or overheat when pulsed at its rated maximum.

Charging ICs & Profiles

Mon, 01 Jan 0001 00:00:00 +0000

Charging ICs & Profiles#

Lithium-ion cells require a precise charging algorithm to reach full capacity without exceeding the voltage limits that cause electrolyte decomposition, lithium plating, or thermal runaway. The standard CC/CV (constant-current / constant-voltage) profile has been the industry norm since the early 1990s, and dedicated charging ICs implement this profile with minimal external components. The difference between a safe, long-lived battery system and one that degrades rapidly or catches fire often comes down to the charging IC selection and configuration.

Protection Circuits & PCMs

Mon, 01 Jan 0001 00:00:00 +0000

Protection Circuits & PCMs#

A lithium-ion cell without protection circuitry is one fault away from a fire. The cell itself has no internal mechanism to prevent overcharge, overdischarge, or overcurrent — those limits exist only in the cell’s chemistry, and violating them causes irreversible damage, capacity loss, or thermal runaway. A protection circuit module (PCM) — sometimes called a battery protection board or BMS for single-cell systems — enforces hard voltage and current limits by switching a pair of MOSFETs in series with the cell. These circuits operate autonomously, using analog comparators rather than programmable registers, and require no firmware interaction. They are the last line of defense when the charging IC malfunctions, the firmware crashes, or the load shorts.

Fuel Gauging & SOC

Mon, 01 Jan 0001 00:00:00 +0000

Fuel Gauging & SOC#

Reporting battery state of charge (SOC) to a user — as a percentage, a bar graph, or a runtime estimate — requires translating raw electrochemical measurements into a meaningful number. The fundamental challenge is that no single measurement directly reveals how much energy remains in a lithium-ion cell. Voltage correlates with SOC but nonlinearly and with heavy dependence on load current and temperature. Current integration (Coulomb counting) tracks charge flow precisely but accumulates drift errors over time. Production fuel gauge ICs combine both methods with impedance tracking and learned cell models to achieve 1–3% accuracy, but even simple firmware-only approaches can produce usable results with appropriate calibration.