[论文解读] Vulnerabilities of Electric Vehicle Battery Packs to Cyberattacks

Shashank Sripad, Sekar Kulandaivel+3 more|arXiv (Cornell University)|Nov 1, 2017

Advanced Battery Technologies Research参考文献 2被引用 13

一句话总结

本文開發了一套物理驅動的模擬框架，用於評估網路攻擊對電動車（EV）電池組的影響，著重於財務與物理損壞。研究發現，受損的電池管理系統（BMS）可能導致過充電或過放電，使新電池壽命縮短至一年以下，並引發不可逆的退化或熱事件。

ABSTRACT

Electric Vehicles (EVs), like all modern vehicles, are entirely controlled by electronic devices embedded within networks that are exposed to the threat of cyberattacks. Cyber vulnerabilities are magnified with EVs due to unique risks associated with EV battery packs. Current batteries have well-known issues with specific energy, cost and fire-related safety risks. In this study, we develop a systematic framework to assess the impact of cyberattacks on EVs. While the current focus of automotive cyberattacks is on short-term physical safety, it is crucial to consider long-term cyberattacks that aim to cause financial losses through accrued impact, especially in the context of EVs. Faulty components of battery management systems such as a compromised voltage regulator could lead to cyberattacks that can overdischarge or overcharge the battery. Overdischarge could lead to failures such as internal shorts in the timescale of minutes through cyberattacks that compromise energy-intensive EV subsystems like auxiliary components. Attacks that overcharge the pack could shorten the lifetime of a new battery pack to less than a year. Further, such attacks also pose physical safety risks via the triggering of thermal (fire) events. Attacks on auxiliary components lead to battery drain, which could be up to 20% of the state-of-charge per hour. Lastly, we develop a heuristic for the stealthiness of a cyberattack to augment traditional threat models. The methodology presented here will help in building the foundational principles of electric vehicle cybersecurity: a nascent but critical topic in the coming years.

研究动机与目标

• 系統性地評估網路攻擊對電動車電池組之長期財務與物理影響。
• 識別電池管理系統（BMS）中可導致過充電、過放電及輔助元件攻擊之弱點。
• 量化網路攻擊如何加速電池退化並縮短壽命，特別是在新電池中。
• 提出一種攻擊隱蔽性啟發式方法，以提升電動車資安威脅建模能力。
• 探討針對單一電池串或電池單元，透過BMS受損而實施之類似「rowhammer」的新型攻擊。

提出的方法

• 使用實驗驗證之熱耦合多物理場電池模型，模擬真實世界之退化過程。
• 將電池模型與車輛動力學模型整合，模擬在攻擊負載下之日常駕駛與充電循環。
• 在標準駕駛範本（如都市動態駕駛測試行程）中實施攻擊情境，例如輔助元件過載與BMS電壓調節器受損。
• 應用CC-CV充電協定，並採用等級1充電器參數，模擬真實世界之充電條件。
• 利用歸一化電阻增加與不可逆容量損失等指標量化損壞程度，以評估性能退化。
• 引入隱蔽性啟發式方法，評估攻擊如何在避開偵測的情況下最大化破壞效果。

实验结果

研究问题

• RQ1 對輔助元件的網路攻擊如何影響電池放電速率與隨時間的退化？
• RQ2 受損的電池管理系統在多大程度上可導致過充電或過放電？其產生的物理與財務後果為何？
• RQ3 電池組的使用年齡如何影響其對網路攻擊引發退化的敏感度？
• RQ4 環境溫度對網路攻擊導致電阻增加速率有何影響？
• RQ5 針對單一電池串或電池單元之類似「rowhammer」的攻擊，是否會導致加速且局部化的退化？

主要发现

• 對輔助元件的網路攻擊可導致電池電量每小時最多損耗20％，顯著縮短行駛里程。
• 透過受損BMS實施之過放電攻擊，可在兩小時內分解固態電解質界面（SEI）層，導致銅溶解與內部短路。
• 過充電攻擊可在一年內使新電池組容量降低至初始值的80％，等同於終止使用狀態。
• 歸一化電阻增加（性能退化的代理指標）在較冷地區更高，且在電池完全充電時攻擊時更為顯著。
• 新電池組因SEI層生長呈非線性趨勢，對輔助元件攻擊之敏感度高於老舊電池組。
• BMS受損可實現類似「rowhammer」之攻擊，選擇性地損壞電池單元之部分組成，增加不穩定性並加速局部退化。