Research On The Thermal Characteristics Of Liquid Metal Batteries For Grid Applications

With the upgrading and restructuring of Chinese economy, the development of new energy industry has been regarded as an important approach to promote the adjustment of industrial structure. The energy storage technologies have attracted widely attention and development as a key to the effective utilization of renewable energy(e.g. solar and wind energy). Liquid metal battery(LMB) is newly emerging developed storage technology with low-cost, high efficiency and long life span in recent years. And it is a new technology which is very suitable to large-scale power grid storage and is expected to be the key to solving the large-scale renewable energy(e.g. solar and wind) to the power grid in the near future.As high temperature battery systems, thermal management is obviously critical to the successful operation of liquid metal battery. All the cell in a module should maintain at its operating temperature. Equally important, cells need to be operated at uniform temperatures because uneven temperature distribution in a module leads to different charge/discharge behavior, which in turn leads to electrically unbalanced cells and reduced modules' performance. Therefore, it is necessary for us to understand and analyze the thermal features of LMB, including temperature distribution and heat generation from cells under various charge/discharge profiles.The thesis is supported by the National Natural Science Youth Foundation Project of ‘the research on the security characteristic of liquid metal batteries' and the cooperative project with Changsha Wasion Group Limited of ‘the applied research on liquid metal batteries'. And the liquid metal battery is the research subject. We combine experimental data and the simulation method to study the thermal characteristic of the cell and the cell module, which can provide a solid scientific foundation for the design of reliable, effective thermal management system for LMBs.The main contents of this paper are summarized as:1. Evaluation of the performance of the liquid metal batteries. Electrochemical performances of liquid metal batteries are evaluated by galvanostatic charge-discharge tests and the temperature effects on the battery performance are clarified.2. The temperature field simulation of the cell. The geometric model of the LMB cell is developed and the initial and boundary condition of the model is determined to analyze, thus we get the temperature distribution within the cell. Meanwhile, the influencing factors on temperature distribution and self-heating conditions of the battery of the liquid metal battery are identified, which are verified by experimental measurements.3. The temperature field simulation of the battery module. The geometric model of the LMB module is built and the temperature characteristics with different heating modes is analyzed. The uniformity of heat distribution, energy consumption and energy efficiency under different heating modes are compared, which will provide theoretical guidance for the heating mode choice of the battery module.