The introduction of Li-ion batteries for grid applications has become evidence as the cost per kWh is continuously decreasing. Although the Li-ion battery is a mature technology for automotive applications and portable electronics, its use for stationary applications needs more validation. The Li-ion technology is considered safe enough for grid storage application, but its lifetime is generally evaluated to be around 10 years. Higher market penetration will be achieved if a longer lifespan could be demonstrated. Therefore, aging evaluation of the batteries becomes crucial. In this paper we investigated the effects of aging after a three years' standby field deployment of a 250 kW/500 kWh Li-ion battery integrated with the grid and solar farm under the harsh climate conditions of Qatar. The development of tools for acquisition and analysis of data from the battery management system (BMS) allows the assessment of the battery performance at the battery stack, string and cell levels. The analysis of the residual capacity after aging showed that the stack suffered from a low decrease of capacity, whereas some inconsistencies have been found between the strings. These inconsistencies are caused by misalignment of a small number of cells that underwent self-discharge during standby at high state of charge.

随着每千瓦时成本的不断降低，将锂离子电池引入电网应用已成为证据。尽管锂离子电池是用于汽车应用和便携式电子产品的成熟技术，但其在固定应用中的使用还需要更多的验证。锂离子技术被认为足够安全用于网格存储应用，但是其使用寿命通常估计为10年左右。如果可以证明更长的使用寿命，将会获得更高的市场渗透率。因此，电池的老化评估变得至关重要。在本文中，我们研究了在卡塔尔恶劣的气候条件下，将250 kW / 500 kWh锂离子电池与电网和太阳能发电场集成在一起的三年备用现场部署后的老化影响。通过开发用于从电池管理系统（BMS）采集和分析数据的工具，可以评估电池组，电池组和电池单元级别的电池性能。老化后的剩余容量分析表明，电池组的容量下降幅度很小，而在电池串之间发现了一些不一致之处。这些不一致是由于少数几个未对准的电池引起的，这些电池在待机状态下处于高充电状态时会进行自放电。