Exicom Refines Battery Administration Techniques with Simulation

The Function of Simulation in Creating Correct BMS

Exicom Tele-Techniques 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 this planet by a single firm. Exicom additionally provides charging options and BMS for electrical two-wheelers and light-weight electrical autos, that are driving the expansion of electrical mobility in India. Exicom’s modern BMS options are prized for his or her efficiency and life.

At Exicom’s R&D middle 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 be chemistry agnostic; it may be used with Li-ion batteries of a spread of chemistries corresponding 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 bold electrification targets, producers should speed up the event of important parts, corresponding to battery administration techniques (BMS)

The precision of the BMS relies on the standard and accuracy of the inputs used for programming or calibrating the system. For instance, the BMS contains quite a few thermal sensors distributed throughout the battery pack. In an effort 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 can be 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 quite a few analyses on the thermal habits of battery cells. In addition they used simulation to investigate potential exterior brief circuits, which may trigger thermal runaway — an uncontrolled self-heating course of that may injury gear and even trigger fires. The Exicom workforce started by analyzing the warmth generated in cylindrical cells with completely different kind elements and additional prolonged this mannequin to the pack stage utilizing the warmth profile generated for the cells. “We had been particularly taken with enhancing the temperature gradient throughout the pack for air-cooled battery packs,” mentioned Dr. Singh.

The outcomes for thermal modeling on the cell stage 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 course of the cell. The visualization on the appropriate exhibits the contour distribution of temperature, the place the utmost temperature is positioned within the energetic materials of the cell.

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

The optimistic and unfavorable terminals of the cell had been shorted by way of 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 obtainable 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 — corresponding to cell geometry, electrode thickness, thermal conductivity, warmth capability, drive cycle, and open-circuit voltage (OCV)-SOC desk — which can be available from battery pack producers.

Extracting these parameters experimentally just isn’t solely a time-consuming course of but in addition vulnerable to errors as a result of variable experimental circumstances. For instance, ambient temperature fluctuates, so extracting an correct warmth profile of a cell requires performing an in depth sequence of checks at completely different ambient temperatures. Utilizing simulation, nevertheless, Dr. Singh and the workforce had been in a position to carry out these experiments with nice ease. They had been in a position to effectively examine cost and discharge profiles, thermal habits at completely different cost and discharge charges, and thermal runaway as a result of exterior or inner brief circuits for various cell chemistries. They had been additionally in a position to 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 most effective positions for deploying the thermal sensors inside the BMS as a way to operate most effectively. Based on Dr. Singh, “COMSOL is an easy-to-learn and adaptable finite factor device for battery design and thermal modeling.”