Rechargeable battery cells are notoriously difficult to analyze. Conductive casings and the close spacing between electrode layers prevent the penetration of radiofrequency into the active compartment, and thus preclude direct nuclear magnetic resonance studies of cells unless they are specifically designed for such studies. Recently, an inside‐out magnetic resonance imaging (MRI) method was developed that allowed measuring the magnetic field distributions in the volume surrounding the cells, and inferring internal parameters, such as the state of charge and current distributions. While the imaging approach provides a potentially very detailed picture of internal mechanisms, it can often be sensitive to background gradients and can be slow. In this work, an alternative approach is presented, which is based on the acquisition of free induction decays in the sample volume surrounding the cells. The signals encode intrinsic battery properties via the induced magnetic fields from the battery materials. A large range of cells were studied with different cathode materials, electrolyte amounts and cycle numbers (age). The spectroscopic signatures from these studies are shown to provide strong classification power for cathode materials. In addition, the derived principal components follow distinct pathways as a function of state of charge. The method is simple and fast (completes in less than a second), and requires only minimal hardware.

中文翻译：

---

可充电电池的超快内外核磁共振评估

众所周知，可充电电池很难分析。导电外壳和电极层之间的紧密间隔可防止射频穿透进入活动隔室，因此，除非对电池进行专门的核磁共振研究，否则它们将无法进行直接的核磁共振研究。最近，开发了一种由内而外的磁共振成像（MRI）方法，该方法可以测量细胞周围体积中的磁场分布，并推断内部参数，例如电荷状态和电流分布。尽管成像方法可能提供内部机制的非常详细的图片，但它通常可能对背景渐变敏感并且速度很慢。在这项工作中，提出了一种替代方法，这是基于对细胞周围样品体积中自由感应衰变的获取。信号通过来自电池材料的感应磁场来编码电池的固有特性。用不同的阴极材料，电解质量和循环次数（年龄）研究了大范围的电池。这些研究的光谱特征显示为阴极材料提供了强大的分类能力。另外，作为电荷状态的函数，得出的主成分遵循不同的路径。该方法简单，快速（不到一秒钟即可完成），并且只需要最少的硬件。用不同的阴极材料，电解质量和循环次数（年龄）研究了大范围的电池。这些研究的光谱特征显示为阴极材料提供了强大的分类能力。另外，作为电荷状态的函数，得出的主成分遵循不同的路径。该方法简单，快速（不到一秒钟即可完成），并且只需要最少的硬件。用不同的阴极材料，电解质量和循环次数（年龄）研究了大范围的电池。这些研究的光谱特征显示为阴极材料提供了强大的分类能力。另外，作为电荷状态的函数，得出的主成分遵循不同的路径。该方法简单，快速（不到一秒钟即可完成），并且只需要最少的硬件。