全固体電池

リチウム金属負極全固体電池では充電時にリチウム金属が不均一に析出してしまい，正常動作できない場合がある事が知られています．本研究では，電池の作成方法を変えた際のリチウム金属の析出形態がどのように変わるかを，X線CTにより計測しました．その結果，所定の圧粉プロセスを用いることで，リチウム金属を均一に析出できることが明らかになりました．
In all-solid-state batteries with a lithium metal anode, it is known that lithium metal can deposit unevenly during charging, which may prevent the battery from functioning properly. This study measured how the deposition morphology of lithium metal changes when the method of battery fabrication is altered, using X-ray CT. The results revealed that employing a specified powder pressing process can achieve uniform deposition of lithium metal.

Journal of Power Sources Advances
Volume 26, April 2024, 100142 https://doi.org/10.1016/j.powera.2024.100142

X線CTは全固体電池の3D電極構造を非破壊で観察可能な強力な構造観察手法ですが，数多くある実験室規模X線CTは，大型シンクロトロンを使用する放射光CTと比較して低解像度であるという欠点がありました．本研究では，適切な機械学習アルゴリズムの選択を行うことで，機械学習により実験室CTの解像度を放射光CTと同等に高めることに成功しました．
X-ray CT is a powerful structural observation technique that enables nondestructive observation of the 3D electrode structure of all-solid-state batteries, but the many laboratory-scale X-ray CTs have the disadvantage of low resolution compared to synchrotron radiation CTs that use a large synchrotron. In this study, by selecting an appropriate machine learning algorithm, we succeeded in increasing the resolution of laboratory-scale CT to the same level as that of synchrotron radiation CT through machine learning.

Energy and AI, Volume 14, October 2023, 100305
https://doi.org/10.1016/j.egyai.2023.100305

全固体電池電極のX線CT像を用いて電池性能をシミュレーションする手法を開発しました．これまでシミュレーションで使用されてきた体積分率と屈曲度に加え，活物質の凝集状態を表現できる比表面積粒径を使用することで，高精度なシミュレーションを実現できることを明らかにしました．
A method for simulating battery performance using X-ray CT images of all-solid-state battery electrodes has been developed. In addition to the volume fraction and tortuosity previously used in the simulation, the specific contact area diameter, which can represent the aggregation state of the active material, is proposed to achieve a highly accurate simulation.

Journal of Power Sources Advances Volume 21, April 2023, 100120 https://doi.org/10.1016/j.powera.2023.100120

リチウム金属を負極に用いると高い電池容量を実現できますが，高速充電時の電池の内部短絡が問題となります．この課題解決法として，電池へのショットピーニング加工を提案し，ショットピーニング加工により充電可能速度を向上できることを実証しました．
Although high battery capacity can be achieved when lithium metal is used as the negative electrode, an internal short circuit in the battery during high-speed charging is a problem. Shot-peening of the battery was proposed as a solution to this problem, and it was demonstrated that the rechargeable speed could be improved by shot-peening.

Journal of Power Sources, Vol.537, p.231556 https://doi.org/10.1016/j.jpowsour.2022.231556

全固体電池は作成時ならびに使用時に加圧されます．このときの電池の内部構造変化を実験室規模のX線CT装置により計測しました．加圧に伴う固体電解質構造の変化を世界で初めて3次元撮像しました．
All-solid-state batteries are pressurized during their production and use. The changes in the internal structure of the battery during this process were measured using a laboratory-scale X-ray CT system. The changes in the solid electrolyte structure under pressure were imaged in three dimensions for the first time in the world.

Journal of Power Sources, No. 462, p.228160 https://doi.org/10.1016/j.jpowsour.2020.228160

全固体電池電極はマイクロスケールの微細な粒の集合体で作成され，その構造の正確な把握は電池の高性能化に重要です．SPring-8の超高解像度放射光CT撮影とAIによる画像処理により，世界最高解像度のクリアな電極の3次元撮像を可能にしました．
All-solid-state battery electrodes are made up of a collection of microscale fine grains, and an accurate understanding of their structure is important for improving battery performance. ultra-high-resolution synchrotron radiation CT imaging at SPring-8 and image processing using AI have enabled clear 3D imaging of electrodes with the highest resolution in the world.

Journal of Power Sources Advances, Vol.8 p.100048 https://doi.org/10.1016/j.powera.2021.100048

全固体電池は圧粉整形されることで電極が作成されます．この圧粉時の応力分布を反映させたイオン伝導シミュレーションにより，高精度で合材電極内のイオン伝導特性を再現可能となりました．
All-solid-state batteries are made by compacting the electrodes. Ion conduction simulations that reflect the stress distribution during the compaction process can reproduce the ionic conduction properties within the composite electrode with high accuracy.

Journal of Power Sources, Vol.470, p.228437 https://doi.org/10.1016/j.jpowsour.2020.228437

全固体電池内の微細空隙はイオン伝導を阻害する要因となることから，その精密計測が必要です．ナノスケールの微細空隙を超小角X線散乱(USAXS)を用いて計測する方法を開発し，放射光CTとの比較からUSAXSにより高精度に計測できることが実証されました．
Since microporosity in all-solid-state batteries is a factor that impedes ionic conduction, precise measurement of microporosity is necessary. We have developed a method to measure nanoscale microporosity using ultra-small angle X-ray scattering (USAXS), and demonstrated that USAXS can measure nanoscale microporosity with high accuracy by comparison with synchrotron radiation CT.

Journal of Power Sources Advances, Vol.12, p.100076 https://doi.org/10.1016/j.powera.2021.100076