USB Charge and PD Charger are everywhere in our lives, mainly used to charge our electronic devices. The battery types used in these devices are mostly lithium-ion batteries. Lithium-ion batteries are currently widely used and have the following characteristics compared to other batteries:
1. High output voltage: The open circuit voltage is usually 3.6V, while the open circuit voltage of nickel-metal hydride batteries and nickel-cadmium batteries is only 1.2V.
2. Large storage capacity: The large energy storage density and high energy capacity are the characteristics of lithium-ion batteries. Compared with nickel-hydrogen batteries, lithium-ion batteries weigh half as much and are 20% smaller in volume for the same output power.
3. Discharge rate: Lithium-ion batteries can be charged quickly, it only takes 1-2 hours to fully charge and reach maximum energy state. At the same time, the self-discharge rate of lithium-ion batteries is low, less than 8% per month, and far lower than the 30% and 40% of nickel-cadmium batteries and nickel-metal hydride batteries, respectively.
Lithium-ion batteries are widely used in USB chargers and PD chargers since they can be charged quickly, have a large storage capacity, and a low self-discharge rate. While charging lithium-ion batteries, the voltage and current will change with time, and it’s crucial to control the charging voltage, limit the charging current precisely, and detect the battery voltage accurately. Unlike nickel-cadmium and nickel-metal hydride batteries, lithium-ion batteries do not exhibit the “memory effect” and can be charged at any point in their discharge cycle. Overcharging a lithium-ion battery can damage the battery; thus, it’s advisable to use current meters or voltage detection circuits to determine when the battery is fully charged. A high-precision battery protection board is often used to prevent overcharging, and the charging voltage should not exceed 4.25V.
Post time: Jun-12-2023