Skew Variation Analysis in Distributed Battery Management Systems Using CAN FD and Chained SPI for 192-Cell Architectures

Abstract

This study explores Skew Variation in 192-cell BMS configurations. Such systems face challenges in maintaining noise-resilient communication across modules. The Controller Area Network with Flexible Data Rate (CAN FD) and daisy-chained Serial Peripheral Interface (SPI) are benchmarked over 5-meter interconnects This paper presents a novel side-by-side analysis of CAN FD and SPI under identical physical conditions in a 192-cell topology, providing quantitative guidance for real-world BMS protocol selection. Protocol behaviors were validated using a dSPACE-based Hardware-in-the-Loop (HIL) setup under fault injection scenarios. CAN FD demonstrates 3x lower BER than SPI at 5 meters. Skew variation in SPI reaches 12 ns versus 4 ns in CAN FD. CAN FD retains 85% of differential margin beyond 4 meters. SPI maintained better latency, with 1.2 ms vs. 1.5 ms for CAN FD. Consider explaining why it's favored: ...due to its simplicity and tight coupling with internal BMS logic. BMS ICs from Texas Instruments and Analog Devices guided protocol integration design. Findings recommend protocol selection based on trade-offs among noise tolerance, communication latency, and wiring architecture. This work distinctively compares both under identical physical constraints. Previous studies have not comprehensively analyzed such long-chain configurations under identical conditions. Results indicate CAN FD offers robust performance in longer, modular topologies. This paper provides comparative, simulation-based design guidance for selecting communication protocols in long-chain, modular BMS configurations.