Main Relay and Precharge Component Selection for Battery PACK

This document details the selection criteria for main relays, precharge resistors, precharge relays, current Hall sensors, and fuses in a battery PACK system for new energy applications. It specifies that the main relay's rated voltage (450V) exceeds the system's maximum voltage (403.2V) and its contact rated current (250A) surpasses the maximum continuous current (114.2A) and peak currents (298.5A for 60s, 515.2A for 10s). The precharge resistor is chosen with a resistance of 82Ω and a maximum power of 8000W, ensuring precharge time under 500ms (actual 342ms) with a 95% voltage ratio, considering capacitor and resistor tolerances. The precharge relay (Panasonic AEC51012 B01) has a rated voltage of 450V and a continuous current of 20A, exceeding the precharge current (4.92A). The current Hall sensor (LEM CAB500-C/SP7) measures up to ±530A, covering the system's maximum peak current (515.2A). The fuse (Mersen A50QS700-4) is rated at 700A and 500V, with a calculated life of 58,400 overloads based on 20 daily cycles over 8 years. All components meet system voltage, current, and environmental requirements, with optimizations recommended in conjunction with BMS strategy.