電池内部の「幽霊」を知る(Getting to know the ’ghost’ inside batteries)

2024-02-08

2024-02-07 アルゴンヌ国立研究所(ANL)

◆アメリカのアルゴンヌ国立研究所の研究者は、バッテリーの初期故障の兆候に関する重要な新情報を明らかにしました。彼らの研究では、「ソフトショート」と呼ばれる状態に焦点を当て、研究コミュニティにより良い電気自動車用のバッテリーを設計するための貴重な知識と方法を提供しています。
◆特にリチウム金属製の陽極を持つ全固体バッテリーに焦点を当て、その動作メカニズムと問題点を詳細に調査しました。彼らの研究では、ソフトショートの発生と影響を理解するために新しい検出および分析手法も開発されました。

＜関連情報＞

固体電池研究におけるダイナミック・ソフトショートの幻の脅威 The phantom menace of dynamic soft-shorts in solid-state battery research

Michael J. Counihan , Kanchan S. Chavan , Pallab Barai , Devon J. Powers , Yuepeng Zhang , Venkat Srinivasan , Sanja Tepavcevic
Joule Published: December 6, 2023
DOI:https://doi.org/10.1016/j.joule.2023.11.007

Context & scale

Solid-state batteries using lithium metal anodes are one of the hottest topics in research today, offering the highest energy density for electrical vehicles and other applications. Many studies highlight their prevention of dendrites that cause the cell to fail by short-circuiting through the electrolyte. However, the nature of these shorts is extremely variable, and some works still fail to address the appearance of soft-shorts in their data. Soft-shorts result in the simultaneous flow of ionic and electronic current, so both symmetric and full cells can appear healthy when, in reality, the cell has already failed. Here, we provide and highlight numerous complementary techniques for identifying and analyzing soft-shorts in all types of batteries, using lithium metal batteries with composite polymer electrolytes as an example system. This work serves as a reference to all battery researchers for presenting accurate data free of soft-shorts to the field moving forward.

Summary

Solid-state batteries with lithium metal anodes present the highest energy density batteries for applications in electric vehicles, leading to massive R&D investments over the past decade. Although most research focuses on preventing lithium metal dendrites that eventually short the battery, the nature of these shorts remains elusive. Soft-shorts, in particular, receive little attention or are not recognized, even in published data. Here, we present a comprehensive outline of the detection and analysis of soft-shorts in solid-state lithium metal cells with composite polymer electrolytes as well as a fundamental understanding of the dynamics of soft-shorts. Transient un-shorting of soft-shorts that occurs on the micro-to-millisecond timescale—driven by joule heating, chemical reactivity, and other processes—limits one’s ability to determine whether the cell was or is still shorted. We provide numerous experimental methods to detect and analyze soft-shorts in any battery type as a resource to all battery researchers.