David Cabezuelo - Mondragon Unibersitatea
Iosu Aizpuru - Mondragon Unibersitatea
Lorea Gorrotxategi - Mondragon Unibersitatea
Unai Iraola - Mondragon Unibersitatea
Lithium Ion (LiOn) electrochemical batteries need to work within a safe voltage and temperature range to avoid irreparable damage. Therefore, these batteries require continuous range control. However, taking all necessary measurements with a BMS while maintaining exhaustive control of the batteries and stable global communication is difficult when there are many cells in place. This is where the versatility and user friendliness of myRIO has been a key factor.
Mondragón Goi Estola Politeknikoa (MGEP) has a laboratory in the Garaia innovation pole equipped to perform different tests on the LiOn cells using these components:
- BaSyTec XCTS Battery Test System
- Prebatem ovens and heaters
- Voltage sources
- Electronic charges
- Spectroscopic impedance meters
Battery testing data collection varies between electrical, thermal, and cycle measurements. Sensitive storage technology also requires an adequate protection system to stop the test if necessary.
To develop our BMS, we integrated LabVIEW and a myRIO device together with a Linear Technology LTC6804-1 multicell battery monitoring chip.
The BMS consists of the LTC6804-1 multicell battery monitoring chip and the myRIO control tool. These communicate via a serial peripheral interface (SPI) communication protocol, where myRIO acts as master and the LTC6804-1 as a slave. The myRIO has an FPGA that is integrated with a processor that executes a real-time OS. It also incorporates multiple digital and analogue inputs and outputs through which the SPI and the LTC6804-1 communicate.
With NI assistance and myRIO examples, programming the SPI communication protocol is simple. LabVIEW offers SPI blocks for myRIO that make configuring speed, polarity, and clock phase easy. We can also painlessly configure the number of bits sent and received per segment. With these configuration options, it is nearly effortless to set up SPI communication for any device. Also, using the spare I/O in myRIO, we can take additional voltage measurements and implement additional security measures.
For this BMS application, myRIO collects all voltage and temperature data that the LTC6804-1 sends via SPI, controls the voltage via the LTC6804 balancing system, and manages the battery’s temperature by controlling a forced ventilation system. Also, LabVIEW helped us easily create a fast and intuitive graphical interface and data storage system.
We tested the BMS at our laboratory. The results were satisfactory, not only because of how well it worked, but also because we rapidly implemented the BMS. We can now better understand the various behaviors of the LiOn cells.
Using myRIO to develop a BMS opened a wide array of possibilities for developing projects or prototypes that are easy to implement. An electrical vehicle control and telemetry, small renewable energy systems, and robotic applications are possible, thanks to myRIO.
Using myRIO and LabVIEW graphical programming, we implemented a BMS for the LiOn cells in a short time because LabVIEW simplified the programming experience and seamlessly paired with embedded hardware that was easily adapted for this application. myRIO versatility also helped in the general design. Additionally, with the LabVIEW front panel, we can view different parameters in real time, giving us constant control over the alarms.