Abstract: To address the issues of circuit disconnection, complex operation, and space constraints in traditional current clamp and series ammeter methods for automotive standby current diagnosis, a non-intrusive measurement method based on fuse voltage drop is proposed by establishing a "voltage drop-resistance-current" mathematical model using Ohm's law. By analyzing the characteristics of fuse circuit body resistance and contact resistance, the equivalent resistance (Raeq≈0.007 5 Ω) is calibrated via the four-wire method, and the standby current calculation formula is derived. Experimental validation is conducted on models such as the BYD Seal 06 DM-i. Results show that this method controls the static current detection error within ±0.5%, improves detection efficiency by 40%, eliminates the risk of circuit damage caused by forceful fuse operation, and reduces module damage risk to 0%. The study provides an efficient and safe technical solution for leakage detection in vehicle electrical systems, which has been standardized in multiple BYD 4S stores and offers a replicable technical path for leakage diagnosis in low-voltage systems of new energy vehicles.

Key words: automotive standby power consumption abnormality; fuse voltage drop measurement; new energy vehicles; non-intrusive diagnosis; contact resistance compensation

摘要： 针对传统电流钳测法与串联电流表法在汽车静态电流诊断中需断开电路、操作复杂及 空间受限的问题，基于欧姆定律构建“压降-电阻-电流”数学模型，提出基于保险丝压降的非 侵入式测量方法。通过分析保险丝回路本体电阻、接触电阻特性，利用四线法标定等效电阻 （Raeq≈0.007 5 Ω），推导静态电流计算公式，并在比亚迪海豹 06 DM-i 等车型上进行实测验证。 结果表明，该方法将静态电流检测误差控制在±0.5%，检测效率提升 40%，避免暴力插拔导致的 电路损伤风险，模块损坏风险降为 0。研究为车载电器系统漏电检测提供了高效、安全的技 术方案，已在多家比亚迪 4S 店实现标准化应用，为新能源汽车低压系统漏电诊断提供了可复 制的技术路径。

关键词: 汽车静态耗电异常；保险丝压降测量；新能源汽车；非侵入式诊断；接触电阻补偿