LiFePO4 batteries are a subtype of lithium ion batteries.
They are mainly used in electricity storage (households and power engineering), for industrial automation and selected types of electric vehicle. What are they made of and why do we choose them from the multitude of lithium batteries?
The selected LiFePO4 prism cells need to be properly prepped before assembly into a battery pack. This always involves first checking the voltage, polarity and overall condition of all cells. Only then should you initiate the recharging, arrangement, fixing in place and interconnection of individual cells.
We secure most battery packs with a management and control system (BMS-Battery Management System). This means battery protection against excessive discharge or overcharging. You can imagine this system like the emergency brake that you find in every single train carriage that prevents the entire train from accident. In practice, it is a simple electrical circuit which constantly measures the electrical voltage of each cell connected to the battery and alternatively the currents supplied to the battery and drawn from it. If voltage of a single cell within the battery exceeds the specifi ed value, the BMS will disconnect the entire battery from the charger or load in order to avoid it being damaged.
Like the emergency brake on a train, disconnection components of the BMS cannot be the only precaution against a crash. A battery pack needs to have a routine method of charging and discharging, like a train’s regular service brake. Disconnecting the pack by BMS is an emergency event, not a piece of ‘information’ for a superior system. Sudden and unexpected disconnection of connected modules from the battery via BMS can cause irreparable damage. Likewise, a sudden outage can be considerably inconvenient for users (equipment ‘suddenly’ stops working, the lights go out…).