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

Battery Diagnostics and Monitoring Advancements in Battery Test Technologies

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

The leading health indicator of a battery is capacity; a measurement that represents energy storage. A new battery delivers (should deliver) 100 percent of the rated capacity. Lead acid starts at about 85 percent and increases in capacity through use before the long and gradual decrease begins. Lithium-ion (Li-Ion) starts at peak capacity and begins its decline immediately, albeit very slowly. Read more about Battery Diagnostics and Monitoring Advancements in Battery Test Technologies