Tech Tuesday: Battery Management System

Posted October 28, 2019

Whether you are an outdoor enthusiast or the weekend warrior it is important to keep your battery running at peak performance. Every outing and adventure you make is priceless and the frustration that can come from a shortened or even canceled trip goes without saying. Our lithium batteries come stock with a battery management system that monitors your battery to help ensure maximum performance and lifespan. Simon gives the full rundown on the importance and function of battery management systems in this week's Tech Tuesday.


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Hi and welcome to this week's edition of Tech Tuesday. LiFePO4 batteries pack a lot of power and value into a small package. Their chemistry is a big part of their superior performance, but there’s another important element attributing to their performance alongside the battery cells themselves: a carefully designed electronic battery management system, or BMS. A well-designed BMS protects, and monitors a lithium battery to optimize performance, maximize life, and ensure safe operation over a wide range of conditions. Today we’re going to focus on one way the BMS protects and optimizes the operation of a LiFePO4 battery, over and under voltage conditions. The cells in a lithium iron phosphate battery operate safely over a range of voltages, typically from 2V to 4.2V. Some lithium chemistry result in cells that are highly sensitive to over-voltage, but LiFePO4 cells are more tolerant. Still, significant over-voltage for a prolonged period during charging can cause plating of metallic lithium on the battery’s anode which permanently degrades performance. The cathode material may also oxidize, becoming less stable, and producing carbon dioxide which may lead to a buildup of pressure in the cell. RELiON’s battery management systems limit each cell and the battery itself to a maximum voltage. For example, the BMS in our RB100 battery protects each cell in the battery and limits the voltage in the battery to 15.6V. Now, under-voltage during battery discharge is also a concern since discharging a LiFePO4 cell below approximately 2.0V may result in a breakdown of the electrode materials. Lithium batteries have a recommended minimum operational voltage. In the RELiON RB100, for example, the minimum recommended voltage is 11V. The BMS acts as a fail safe to disconnect the battery from the circuit if any cell drops below 2.0V. So, while the BMS may not be visible, it plays a very important role in making sure each cell in your battery remains within safe limits.



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