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Purpose-This paper presents the development of a body-mounted robotic assistant for magnetic resonance imaging (MRI)-guided low back pain injection. Our goal was to eliminate the radiation exposure of traditional X-ray guided procedures while enabling the exquisite image quality available under MRI. The robot is designed with a compact and lightweight profile that can be mounted directly on the patient's lower back via straps, thus minimizing the effect of patient motion by moving along with the patient. The robot was built with MR-Conditional materials and actuated with piezoelectric motors so it can operate inside the MRI scanner bore during imaging and therefore streamline the clinical workflow by utilizing intraoperative MR images. Methods-The robot is designed with a four degrees-of-freedom (DOF) parallel mechanism, stacking two identical Cartesian stages, to align the needle under intraoperative MRI-guidance. The system targeting accuracy was first evaluated in free space with an optical tracking system, and further assessed with a phantom study under live MRI-guidance. Qualitative imaging quality evaluation was performed on a human volunteer to assess the image quality degradation caused by the robotic assistant. Results-Free space positioning accuracy study demonstrated that the mean error of the tip position to be 0.51 ± 0.27mm and needle angle to be 0.70 ± 0.38°. MRI-guided phantom study indicated the mean errors of the target to be 1.70±0.21mm, entry point to be 1.53 ± 0.19mm, and needle angle to be 0.66 ±0.43°. Qualitative imaging quality evaluation validated that the image degradation caused by the robotic assistant in the lumbar spine anatomy is negligible. Conclusions-The study demonstrates that the proposed body-mounted robotic system is able to perform MRI-guided low back injection in a phantom study with sufficient accuracy and with minimal visible image degradation that should not affect the procedure.

Lithium-ion batteries (LIBs) have never been more in demand than they are today, with production capacities projected to grow exponentially in the coming years. [1] Especially in the course of climate change, the switch from fossil fuels to renewable energies is becoming inevitable. Energy generation in particular requires sustainable storage media with LIB as the basis for sustainable mobility. [2] This high demand makes it necessary to produce LIB even faster. The production steps of LIB exhibit complex interdependencies, which poses a challenge for high-quality and high-throughput cell manufacturing. In this context, the process of electrolyte wetting and subsequent formation are examined, which are located at the end of the production chain and represent a significant bottleneck in battery production due to the long process times of up to 3 weeks. [3] The goal of the wetting is to fill every pore with electrolyte liquid, which enables the ionic transport in the cell. [4] According to Lanz et al., the wetting of LIB has to be completed before starting the formation process. [5] With completed wetting, the initial charging leads to the formation of the solid electrolyte interphase (SEI), a passivation layer on the anode active material. [6] Wetting and formation take 3-7 days, which means that it is a bottleneck in battery production because time and storage capacities are required. [7] Drees et al. focused on accelerating the formation process. [8] The authors successfully developed a fast-charging formation procedure that reduced the formation time by over 53% compared to conventional formation procedures. Thus, only 45 min were needed for the formation of the considered cell configuration. [8] With the formation times already improving, there remains potential for accelerating the wetting process in order to decrease process times in the cell finalization. Kampker et al. concluded that the wetting of hardcase cells can be accelerated with the use of pressure. [9] Wood et al. studied the effect of pressure on the wetting process and found that even after 12 and 24 h, there was still a fraction of the pore volume that remained unwetted. [3] According to Günter et al., the wetting time could be improved from 7.5 h in 2019 [10] to 3 h in 2022 [11] by only changing the process design and parameters. The authors achieved a quicker complete wetting through low pressure at the first dosing step and an overpressure in the second dosing step. [11] Kampker et al. explain that a complete wetting is essential to ensure a safe and proper functioning of the battery cells. [9] Kwade et al. support this statement but elaborate that an unfinished wetting requires multiple formation cycles in order to fully develop

Improving the energy density of lithium-ion batteries advances the use of novel electrode materials having a high specific capacity, such as nickel-rich cathodes and silicon-containing anodes. These materials exhibit a high level of gas evolution during formation, posing a safety hazard during operation. Analyzing the gas volume and the gassing duration is thus crucial to assess material properties and determine suitable formation procedures. We present a novel method for evaluating both gassing and swelling simultaneously to determine the operando gas evolution of pouch cells with volume resolutions below 1 µl. Dual 1D dilatometry is performed using a cell expansion bracket which applies a quasi-constant force on the cell, thus providing reproducible formation conditions. The method was validated using the immersion bath measurement and NCM/graphite pouch cells were compared to high-energy NCA/silicon-graphite pouch cells. Silicon-containing cells exhibited gas evolution higher by a factor of seven over ten successive cycles, thus demonstrating the challenges of high-silicon anodes. The concurrent dilation analysis further revealed a constant thickness increase over the formation, indicating continuous solid electrolyte interface growth and lithium loss. Consequently, the method can be used to select an ideal degassing time and to adjust the formation protocols with respect to gas evolution.

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