Usable time estimation and suitable battery selection for electric tractor considering agricultural operational load

초록

This study estimates battery usable time and discharge rates, and selects a suitable battery for a single-motor electric tractor using dynamometer tests and rotary tillage at L-slow, L-fast, and M-slow gear stages. The dynamometer results were validated for rotary tillage to determine a suitable battery for full-day (8 h) operations. In dynamometer tests, battery power consumption for light, medium, and heavy-duty loads was 6.25, 8.76, and 14.51 kW, resulting in usable times of 3.00, 2.33, and 1.25 h, respectively. Rotary tillage results confirmed similar battery consumption trends, validating the dynamometer-based estimation. For continuous 8-hour operations, a 900 Ah battery (64.8 kWh) was satisfied at the gear stage of L-fast for rotary tillage. It was observed that battery mass and volume increased proportionally with energy density. Results confirmed that higher energy storage required a larger and heavier battery pack for full-day operations. The battery energy density of 64.8 kWh (900 Ah) would be suitable with practical weight and space limitations to perform full-day operations. The limitation is that traction efficiency, slip ratio, and effective field capacity were not considered for suitable gear stage selection. However, we believe that this study provides a feasible technique for battery selection in real agricultural scenarios, offering practical insights for electric tractor manufacturers.

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