The Function of Simulation in Growing Correct BMS

Exicom Tele-Methods Pvt. Ltd. designs, develops, and deploys power options, together with the newest Li-ion battery applied sciences. Thus far, it has deployed Li-ion battery options totaling greater than 1.8 GWh — among the many highest on the planet by a single firm. Exicom additionally gives charging options and BMS for electrical two-wheelers and light-weight electrical automobiles, that are driving the expansion of electrical mobility in India. Exicom’s progressive BMS options are prized for his or her efficiency and life.

At Exicom’s R&D heart in Gurugram, India, the expertise workforce led by Dr. Parmender Singh has developed a BMS that can be utilized to exactly monitor and handle Li-ion batteries in functions throughout a broad voltage vary (as much as 1000 V). This BMS can also be chemistry agnostic; it may be used with Li-ion batteries of a spread of chemistries comparable to lithium ferrophosphate, or lithium iron phosphate (LFP), lithium nickel manganese cobalt oxide (NMC), and lithium nickel cobalt aluminum oxide (NCA).

For India’s transportation sector to fulfill its formidable electrification targets, producers should speed up the event of important parts, comparable to battery administration programs (BMS)

The precision of the BMS will depend on the standard and accuracy of the inputs used for programming or calibrating the system. For instance, the BMS consists of numerous thermal sensors distributed throughout the battery pack. To be able to precisely monitor a battery pack’s temperature distribution and predict corresponding efficiency, it’s crucial that the sensors be positioned on the proper areas. This requires an in depth understanding of the warmth profile of every battery cell in addition to how warmth varies all through the pack. That is the place COMSOL Multiphysics performs an integral half, by permitting for correct computation and collation of the inputs, like warmth profile data, which are required to develop a BMS with surgical precision.

Predicting and Stopping Potential Thermal Runaway

Dr. Singh’s workforce at Exicom used COMSOL Multiphysics to carry out numerous analyses on the thermal habits of battery cells. In addition they used simulation to investigate potential exterior brief circuits, which might trigger thermal runaway — an uncontrolled self-heating course of that may harm gear and even trigger fires. The Exicom workforce started by analyzing the warmth generated in cylindrical cells with totally different type components and additional prolonged this mannequin to the pack degree utilizing the warmth profile generated for the cells. “We had been particularly eager about enhancing the temperature gradient throughout the pack for air-cooled battery packs,” mentioned Dr. Singh.

The outcomes for thermal modeling on the cell degree for cylindrical cells throughout a 1C discharging are proven in Determine 1. The visualization on the left in Determine 1 exhibits the temperature distribution, the place the utmost temperature is noticed in the midst of the cell. The visualization on the fitting exhibits the contour distribution of temperature, the place the utmost temperature is situated within the energetic materials of the cell.

The simulation outcomes, when validated with experimental findings, had been noticed to be throughout the error limits of ±5 p.c at the usual cost–discharge profile. The mannequin was then additional prolonged for 2C discharge at 100% state of cost (SOC) in keeping with Normal UL1642, which is outlined for exterior brief circuit testing.

The optimistic and damaging terminals of the cell had been shorted through an 80 ±20 mΩ resistance. The COMSOL software program’s lumped approach-based thermal mannequin was validated towards experimental information for cost–discharge profiles of the cell. In addition they developed:

• Cyclic and calendric capacity-fade fashions for cylindrical cells based mostly on the optimization options accessible in COMSOL
• A high-fidelity pseudo two-dimensional (P2D) mannequin for cylindrical cells utilizing extracted electrochemical parameters

They discovered that the lumped method enabled them to assemble fashions utilizing a minimal variety of parameters — comparable to cell geometry, electrode thickness, thermal conductivity, warmth capability, drive cycle, and open-circuit voltage (OCV)-SOC desk — which are available from battery pack producers.

Extracting these parameters experimentally is just not solely a time-consuming course of but additionally susceptible to errors resulting from variable experimental circumstances. For instance, ambient temperature fluctuates, so extracting an correct warmth profile of a cell requires performing an intensive sequence of assessments at totally different ambient temperatures. Utilizing simulation, nevertheless, Dr. Singh and the workforce had been capable of carry out these experiments with nice ease. They had been capable of effectively research cost and discharge profiles, thermal habits at totally different cost and discharge charges, and thermal runaway resulting from exterior or inside brief circuits for various cell chemistries. They had been additionally capable of establish the hotspots within the battery pack and decide the cell grading based mostly on capability fade evaluation with excessive accuracy. These outcomes had direct functions in lowering the event cycle time of the BMS, because the hotspots indicated the very best positions for deploying the thermal sensors throughout the BMS in an effort to operate most effectively. In keeping with Dr. Singh, “COMSOL is an easy-to-learn and adaptable finite component instrument for battery design and thermal modeling.”