Lithium-ion battery setups have quickly become the go-to power storage solution of the future, offering numerous benefits when compared to lead-acid batteries. With higher efficiency, less weight, and a longer lifespan, a lithium battery is simply the better choice for business applications. A battery management system (BMS) combines lithium batteries with electronics that monitor their performance and ensure that each battery within the BMS is operating safely. Not only does this increase the service life of the batteries themselves, but it also offers a layer of protection to the equipment that the battery is used to power.
What Is the Function of a Battery Management System?
Businesses can utilize a battery management system to protect against overcharging and over-discharging, as well as to monitor temperature, lithium-ion battery health, and overall safety in terms of shorts or loose connections. These systems are designed to keep each lithium battery within the BMS functioning at its maximum capacity to ensure that power is there when you need it most.
How Does a Battery Management System Work?
By monitoring each individual cell within the batteries, a BMS will calculate acceptable current levels for charging and discharging that prevent damage. One of the fastest ways to ruin a lithium battery is to overcharge it, which is why monitoring and managing current is essential to increasing overall longevity. In the case of traditional lead-acid batteries, the available power gradually drains and dies, whereas lithium batteries within a BMS will simply turn off when the power level reaches a specific threshold.
Why a BMS Is Important?
Battery health and safety are the two crucial reasons for investing in a BMS. A lithium-ion battery contains a liquid electrolyte that is extremely flammable, and protecting the user, the equipment, and the battery is a high priority. A fire of this type can be highly dangerous, but a BMS ensures that each lithium battery can operate safely and be useful over the course of a long service life.
Protections Offered by a Battery Management System
- Under and Over Voltage. If you overcharge a lithium battery, you will damage it and compromise its safety and lifespan — likewise, if you over-discharge it, the cell voltage becomes too low, and damage will occur. By monitoring each cell, a BMS will protect against either situation.
- Temperature Extremes. High temperatures outside of safe operation will also damage your batteries, as well as create a dangerous situation for users and equipment. Specifically, thermal runaway occurs when the temperature reaches a critical level which can create an inextinguishable flame. A good BMS will not only prevent temperatures from rising to such a level, but many also control cooling fans that will help to keep temperatures within a desired operating range.
- Protection From Shorts. If a short occurs within the battery, it can cause thermal runaway, which leads to an extremely dangerous fire. Both internal and external shorts can be prevented by the use of a good quality battery management system.
Types of Battery Management Systems
There are four main types of battery management systems:
- Centralized BMS Architecture. One BMS controls all batteries within the pack assembly. This offers a compact and economical solution for many business needs, though there are numerous wires and connectors involved, which can make maintenance more involved.
- Modular BMS Topology. Dividing the BMS into separate modules, modular BMS topology uses sets of dedicated wires that connect to other portions of the battery stack. A primary BMS is sometimes used to monitor each submodule, but this solution provides easier troubleshooting at a slightly higher cost.
- Primary/Subordinate BMS. Similar to a modular setup, this BMS type uses a master/slave configuration to divide responsibilities. The primary handles computation while the secondaries focus on providing measurement information.
- Distributed BMS Architecture. A distributed BMS uses control boards for each battery module which are then monitored by a main controller. This leads to fewer wires, but can make maintenance a bit more involved.
