1. Lithium battery voltage rise and fall test


Firstly, let the lithium battery be lowered to 3.3V through a voltage reducing chip, then supply power to the microcontroller and Bluetooth module, and plan to increase it to 7V to carry a load.


Result: The Bluetooth module is not working and cannot be searched. Remove Bluetooth, the microcontroller and load are working normally. When the microcontroller is removed, Bluetooth and the load work normally. When not using voltage reduction and separately supplying a set of power sources, all three work normally.


Explanation: XC6206 for voltage reduction and FD6291 for voltage boosting.


2. Boost and buck issues of lithium batteries


Let's analyze the reasons for the above problems and identify the common faults of lithium pool pressure rise and fall. Let's learn together.


The individual voltage of lithium-ion batteries has a certain range, for example, the normal operating voltage range of lithium iron phosphate batteries is 2.5V-3.65V, and the normal operating voltage range of lithium manganese oxide and ternary batteries is 3V-4.2V.


When the total voltage of lithium-ion batteries is 60V or below in application, a battery protection plate is required. When the voltage is above 60V, a Battery Management System (BMS) is required. The function of these two devices is to protect the battery from working properly.


Note that after the number of strings in the battery pack is set, the voltage of the battery pack cannot be adjusted arbitrarily. The voltage variation of the battery pack can only vary within the normal operating voltage range: during charging, it rises from the lower voltage limit to the upper voltage limit. When using electricity, the voltage drops from the upper limit to the lower limit.


Understood this issue, if you want a wide range of voltage rise and fall for lithium batteries, you can adjust it freely.


The best solution is to make a good battery pack, equip it with a suitable inverter, and then equip it with a DC voltage regulator to meet the requirements for boosting and lowering lithium batteries.


Explanation: This method is rarely used in practical applications unless the AC power source frequently experiences power outages or when solar or wind energy is used to charge the battery pack. Only then will this method of boosting and lowering voltage be considered.


The above methods for boosting and lowering the voltage of lithium batteries can be used in experiments to study the learning effect.