What does BMS mean? A BMS is a battery management system often used in a medium or large format lithium-ion battery pack. A BMS is a PCB (circuit board) that provides protection, monitoring, balancing, and other high-level functionality for a battery pack.
Whether it be a 18650 BMS, solar BMS, or one for electric vehicles they all have a similar function. This contrasts with a PCB PCM (protection circuit module) which is also a circuit board with protection but is smaller and less sophisticated. A PCM is used in small format battery packs, for example in consumer electronic devices.
A BMS will work with most formats of lithium-ion batteries, including the 18650 battery, and the lithium polymer battery.