The correct method of connecting lithium-ion batteries in series

The correct method of connecting lithium-ion batteries in series requires high-power portable devices that are usually powered by a battery pack with two or more batteries connected in series. If a high-voltage battery is used, the size of the conductor and switch can be made very small. Mid-priced industrial power tools usually use batteries with voltages ranging from 12V to 19.2V. Advanced power tools use batteries and voltages from 24V to 36V to get more power. The automobile industry eventually increased the ignition battery voltage of the starter from 12V (14V in fact) to 36V or even 42V. The battery consists of 18 lead-acid batteries connected in series. In the early hybrid vehicles, the driving battery voltage was 148V. Newer models use batteries with voltages up to 450 to 500 volts, mostly nickel-based chemical batteries. The 480V Ni-MH battery consists of 400 series of Ni-MH batteries. Some hybrid vehicles have also been tested with lead-acid batteries. 42-volt batteries are expensive and have more arcs on switches than 12-volt batteries. Another problem with using high-voltage battery packs is that one of the batteries in the battery pack may fail. It is like a chain, the more batteries you connect, the more likely this will happen. Whenever there is a problem with the battery, its voltage will drop. Finally, a disconnected battery may interrupt the current flow. It is not easy to replace a bad battery because the old and new batteries do not match. Generally speaking, the capacity of new batteries is much larger than that of old batteries. Taking the battery pack as an example, the voltage of the third battery is only 0.6V instead of the normal 1.2V (Figure 1). As the working voltage drops, it reaches the critical point of discharge faster than a normal battery pack, and its service life is greatly shortened. Once the device is shut down due to low voltage, the remaining three batteries are still in good condition and cannot supply the stored power. At this time, the third battery also exhibits a larger internal resistance. If there is a load, the output voltage of the entire battery chain will be greatly reduced. In a set of serial batteries, a poorly performing battery, like a plug blocking a water pipe, will have a huge resistance to prevent the flow of current. The third battery will also be short-circuited, causing the terminal voltage to drop to 3.6V, or disconnect the battery to cut off the current. The performance of the battery pack depends on the performance of the worst battery pack. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: Introducing the charging system of lithium-ion batteries and nickel-cadmium batteries