How to Charge Li-Ion with a Parasitic Load

Contributed commentary by Isidor Buchmann, CEO & Founder, Cadex Electronics Inc.

Charging a battery is simple but the complexity rises when a parasitic load is present during charge. Depending on battery chemistry, the charge process goes through several stages, and with lithium-ion Stage 1 consists of a constant current (CC) charge that brings the battery to roughly 70 percent state-of-charge (SoC). The cell reaches 4.20V/cell, a common voltage limit for Li-ion, after which Stage 2 continues by applying a constant voltage (CV) charge. The current begins to drop as the battery saturates. Full-charge is reached when the current decreases to typically 0.05C, which is one-twentieth of the rated ampere-hour. Li-ion cannot absorb overcharge and no charge is applied in Stage 3. Figure 1 illustrates typical voltage, current and capacity signatures of the CCCV charge. Read more about How to Charge Li-Ion with a Parasitic Load

Battery Rapid-Test Methods

Contributed Commentary by Isidor Buchmann, CEO & Founder, Cadex Electronics, Inc.

A battery resembles a living organism that cannot be measured; only estimated by diagnostics similar to a doctor examining a patient. The accuracy of rapid-testing varies according to symptoms that change with state-of-charge (SoC), agitation after charge and discharge, temperature and storage. A rapid-test must distinguish between a good battery that is partially charged and a weak pack that is fully charged. Both will deliver similar runtimes in the hands of the user but have different performance levels. Read more about Battery Rapid-Test Methods

Ultra-Fast Charging: Respecting the Limits of a Battery when Feeding

Content Contributed by Isidor Buchmann, CEO & Founder, Cadex Electronics, Inc.

Consumers demand faster charging times. Leading in this movement is the electric vehicle (EV) industry that strives for charge times similar to filling up a vehicle at a gas station. Pumping 50 liters (13 gallons) of fuel into a tank holds a calorific value of 600 kWh. The fill-up is quick. An EV battery, in comparison, only stores between 50 to 100 kWh of energy and charging takes a long time. Read more about Ultra-Fast Charging: Respecting the Limits of a Battery when Feeding

Battery Diagnostics On-the-Fly: Removing the “Black-Box” Stigma by Making Performance Transparent

Isidor Buchmann, CEO & Founder, Cadex Electronics, Inc.     

Battery users imagine a battery pack being an energy storage device that resembles a fuel tank dispensing liquid fuel. For simplicity reasons, a battery can indeed be perceived as a vessel storing electrical energy; however, measuring energy flowing into an electrochemical device and then drawing it out again is far more complex than handling liquid fuel. While a hydraulic fuel gauge measures liquids moving in and out of a tank of known size, a battery fuel gauge reads units of current. Battery size is specified in ampere hours (Ah), and what makes estimating battery state-of-charge (SoC) and state-of-health (SoH) so challenging is an unsteady state; a battery loses capacity with each charge and leaks energy in the form of self-discharge. Read more about Battery Diagnostics On-the-Fly: Removing the “Black-Box” Stigma by Making Performance Transparent