The lithium compound is used as the battery material for the electrode, materials containing lithium elements is used as electrolyte (always is LiPF6), such as 3.2V LiFePO4, 3.6V LiNiCoMnO2, 2.4V LiTiO2, 3.7V LiCoO2, all are lithium-ion battery.

When working (using), the battery will be charged or discharged, one time discharge, then charge after the discharge, we call it’s one cycle. After many times discharge and charge, the retention capacity will be less and less, when it can keep 80% or initial capacity, we say the life is over, the cycle times is called cycle life.

When discharge, some energy/capacity will be released from the battery, the energy discharging-ratio is called DOD, e.g depth of discharge, for example, a full charged 100Ah battery is discharged 20Ah capacity, we say the DOD is 20%, if discharged 80% capacity, we call it 80% DOD, if all 100Ah capacity is discharged, we call it 100% DOD or full discharge.

It’s a guide voltage for the devices (e.g inverter, ups….) to stop discharging when the battery voltage drops to a specified value during the discharging period. E.g for a 12V LiFePO4 battery, the COV (cut off voltage) is 11.2V.

It’s a specified voltage that for BMS to cut off the discharging when the battery voltage drops lower than some value during the discharging period. E.g for a 12V LiFePO4 battery, the protection voltage is 10.8V. It’s also called over-discharge-protection voltage or under voltage protection voltage.

Battery management system and Battery monitoring system, both are called BMS.

Battery management system is used to manage the cells, protect the cells from over-discharge, over-charge, over current, short circuit, high temperature, low temperature.

Battery monitoring system is used to show the cells/battery information, such as cells voltage, battery voltage, and capacity, and temperature, current, discharge/charge status, protection information and so on. Some battery monitoring system even supports the controlling or remote controlling the battery management system from WiFi, 4G, Bluetooth, zigbee and so on.

A cell with round shapes, like 18650, 21700, 26650, 32650, 321350 cells.

A cell with cube shapes, like the famous brand BYD, CATL, they supply cube cells for electric vehicles.

Lithium battery standard is 5 hours rate. E.g a 100Ah battery, discharge with 0.2CA current (0.2 x 100 =20A) and the discharge time is not less than 5 hours when the voltage drops to 11.8V. We call the battery capacity is 100Ah (20A x 5 hours = 100Amp hour).

The battery is charged with a small current (less than 0.2CA) is called standard charge; the charge current between 0.2CA to 0.5CA is called quick charge; the charge current between 1CA to 2CA is called supper quick charge. E.g a 100Ah battery, the standard charge current is 20a, battery can be full charged in 5.5 hours; the quick charge current is from 20A to 50A, battery can be full charged in 2.5 hours; the supper quick charge current is from 100A to 200A, the battery can be full charged in 1.3 hours.

Under normal circumstances, the discharge rate of lithium batteries is between 1C and 3C. For example, 100Ah battery, the general maximum discharge current is between 100A and 300A, according to customer requirements.