DMC developed a highly available and scalable distributed test system that leverages the power and flexibility of NI’s hardware and software platforms, including PXI, cRIO, LabVIEW for Windows, Real-time, and FPGA.
Background
DMC was approached by a world-class research laboratory and long standing client with strict requirements for a facility-wide battery and fuel cell test system upgrade. This facility is key in providing accurate and independent assessments of emerging energy storage technologies. A major motivation for this system was to have an open architecture allowing an extreme degree of flexibility, both in the devices that can be tested and in the electrical hardware that can perform the battery cycling.
Developing the Test System
DMC collaborated with the laboratory engineering and research staff to define hardware and software specifications for a fully configurable battery and fuel cell testing facility. The specifications required a highly flexible platform capable of producing consistent test results using a variety of test fixture hardware and wide array of data acquisition instruments.
NI PXI was selected as the primary hardware platform based on the wide selection of Input/Output modules and high performance of the controllers, as well as the ease of connectivity to other devices as needed (such as RIO and SCXI).
LabVIEW Real-Time was the software platform selected for test execution, based on determinism and standalone reliability. LabVIEW for Windows was selected for other functions, such as hardware configuration, test definition, and live monitoring. LabVIEW and DIAdem were selected for data retrieval, viewing, and report generation. The LabVIEW database toolkit was selected for managing sample and test information, and the TDMS file format was selected for raw data storage.
In addition to enabling mission-critical test execution, the NI hardware and software tools enabled easy interfacing to various battery cycler hardware. For example, a GPIB-enabled 5kW power supply can be replaced with an Ethernet-enabled 250kW power supply with a simple configuration change.
Similarly, the tools enabled custom interfacing to various devices under test. For example, a smart EV battery pack may use a unique CAN-based protocol for communicating to its BMS (Battery Management System). The NI-CAN interface can be used to easily adapt to the new protocol, and incorporate data available from the unique BMS into the data stream already being acquired.
System Description
The test lab uses a network of distributed test nodes. A PXI chassis forms the basis of these nodes, with each node capable of running 10+ asynchronous tests for 1000 hours or more. Each of the asynchronous nodes has access to all of the PXI IO (hundreds available). The nodes store data on a central data server. “Console” PCs run LabVIEW executables to define, start, and monitor these tests. These Console PCs also have access to data that reside on the data server. A terminal server is employed to allow traveling researchers to monitor active and completed tests.
There are specific nodes that run fuel cell tests. These nodes consist of a PXI chassis, a cRIO for low-level fuel flow control, an SCXI chassis for additional data channels, multiple RIO PXI cards, and multiple C-series chassis for isolated voltage measurements. This system is capable of controlling and collecting data from bare fuel cell stacks of up to 500 cells (producing 500V end to end).
Battery and Fuel Cell test environments can present significant safety concerns. A lab-wide safety system was developed and implemented using NI cRIO and LabVIEW Real-Time. The safety controllers monitor lab conditions and issue automated shutdown commands to distributed test nodes upon detection of unsafe conditions. The controllers also notify staff via email. The system also provides current lab safety state information via the cRIO webserver.
The Results
"Much of the functionality was simply not available in the legacy system. By choosing off-the-shelf solutions from National Instruments, we were able to increase our testing load significantly that results in saved engineering time." – Research Engineer
The system provides a modular, scalable, and fully configurable test facility allowing the engineers and scientists to accommodate and accurately test a wide variety of energy storage devices. Furthermore, the high level of flexibility enables test results without requiring the use of any one specific battery cycler hardware device, allowing future growth and capability.
Learn more about DMC's Test and Measurement Automation expertise.