Connecting Lithium Batteries in Series: Understanding the Basics

Lithium batteries have become increasingly popular in recent years due to their high energy density, long life span, and low self-discharge rate. They are commonly used in various electronic devices, such as smartphones, laptops, and electric vehicles. However, in some cases, a single lithium battery may not provide enough voltage to power a device, and multiple batteries need to be connected in series.

 

Connecting lithium batteries in series is a common practice in the electronics and automotive industries. When two or more batteries are connected in series, the positive terminal of one battery is connected to the negative terminal of the next battery, resulting in a higher total voltage output. For example, two 3.7-volt lithium batteries connected in series will produce a total output of 7.4 volts.

 

However, connecting lithium batteries in series requires careful consideration and attention to safety. Here are some of the basics you should understand before attempting to connect lithium batteries in series.

 

Battery Capacity

 

The capacity of a battery refers to the amount of electrical charge it can store and is measured in ampere-hours (Ah). When lithium batteries are connected in series, their capacities add up, but the voltage remains the same. For example, connecting two 5000mAh batteries in series will result in a total capacity of 10,000mAh, but the voltage will remain the same as the individual batteries (usually 3.7 or 3.8 volts).

 

Voltage

 

As mentioned earlier, connecting lithium batteries in series increases the total voltage output. However, it’s essential to ensure that the voltage rating of the batteries matches the device’s voltage requirement. Connecting batteries with different voltage ratings in series can result in uneven charging and discharging, reducing the battery life span and potentially damaging the device.

 

Balancing

 

When lithium batteries are connected in series, they should be balanced to ensure that each battery receives an equal charge and discharge. This is particularly important for batteries of different ages or capacities. Battery balancing can be achieved by using a balancing charger or a battery management system (BMS).

 

 

 

Safety

 

Lithium batteries are known for their high energy density, which means they can store a lot of energy in a small space. However, this also makes them prone to overheating, swelling, or even exploding if not handled properly. When connecting lithium batteries in series, it’s crucial to follow the manufacturer’s instructions and take appropriate safety measures, such as using a battery holder or insulating tape to prevent short circuits.

 

Conclusion

 

Connecting lithium batteries in series can provide a higher voltage output, but it requires a basic understanding of battery capacity, voltage, balancing, and safety. By following the guidelines and taking safety precautions, you can safely and effectively connect lithium batteries in series for your electronic or automotive projects.