1、锂电池升降压试验

首先，让锂电池通过降压芯片降到3.3V，然后给单片机与蓝牙模块供电，另打算升到7V去带一个负载。

结果：蓝牙模块不工作，且搜索不到。去掉蓝牙，单片机和负载均正常工作。当去掉单片机时，蓝牙与负载正常工作。不使用降压，单独给一组电源时，三者均正常工作。

2、锂电池升压与降压问题

下面来分析下以上问题的原因，找准锂池池升降压常见故障的问题所在，一起来学习下。

锂离子电池的单体电压有一定范围，比如磷酸铁锂电池的正常工作电压范围是2.5V-3.65V，锰酸锂以及三元电池的正常工作电压范围是3V-4.2V。

锂离子电池在应用中，当总电压在60V及以下时，需要电池保护板。60V以上时，需要用到电池管理系统（BMS）。这二个设备的作用得保护电池正常工作。

注意，在电池组的串数定下来后，不能随意调整电池组电压。即电池组的电压变化只能在正常工作电压范围内变化：充电时，从电压下限上升到电压上限。用电时，从电压上限下降到电压下限。

明白了这个问题，如果想让锂电池的升降压范围很大，可随意调节。

最好的解决方法：做好一组电池组，配一个合适逆变器，再配一个直流调压器，就可以满足锂电池的升压与降压要求。

说明：这种方法在实际应用中很少用到，除非所使用的交流电源经常停电，或用太阳能或风能给电池组充电时，才会考虑这种升压与降压的方法。

以上锂电池的升压与降压方法，可在试验时使用，用来研究学习效果不错。

1. Lithium battery voltage rise and fall test

First, let the lithium battery drop to 3.3V through the step-down chip, then supply power to the microcontroller and Bluetooth module, and plan to rise to 7V to carry a load.

Result: The Bluetooth module does not work and cannot be searched. With Bluetooth removed, the MCU and the load work normally. When the microcontroller is removed, Bluetooth and the load work normally. When a group of power supplies are separately supplied without voltage reduction, all three will work normally.

2. Voltage rise and drop of lithium battery

Next, we will analyze the causes of the above problems, find out the common problems of the pressure rise and fall of the lithium pool, and learn together.

The single voltage of lithium ion battery has a certain range, for example, the normal working voltage range of lithium iron phosphate battery is 2.5V-3.65V, and the normal working voltage range of lithium manganate and ternary battery is 3V-4.2V.

In the application of lithium ion battery, when the total voltage is 60V or below, the battery protection board is required. Above 60V, the battery management system (BMS) is required. The function of these two devices is to protect the battery.

Note that the voltage of the battery pack cannot be adjusted at will after the number of strings of the battery pack is determined. That is, the voltage change of the battery pack can only be changed within the normal working voltage range: when charging, it rises from the lower voltage limit to the upper voltage limit. When power is used, it drops from the upper voltage limit to the lower voltage limit.

I understand this problem. If you want to increase or decrease the pressure range of lithium battery, you can adjust it at will.

The best solution: a set of batteries, a suitable inverter, and a DC voltage regulator can meet the pressure rise and drop requirements of lithium batteries.

Note: This method is rarely used in practical applications. Unless the AC power supply used is often cut off, or the solar or wind energy is used to charge the battery pack, this method of boosting and reducing voltage will be considered.