Sweat Testing Cycles of Batteries for Different Electrical Power Applications

Abstract

This paper looks at six different applications for a domestically located battery system and determines how these could be translated into different electrical power application 'drive' cycles. The applications considered are as follows: 1) A house with four people and a solar panel using the battery to absorb extra energy when the PV panel is producing more power than is absorbed in the house and then releasing this energy afterwards. 2) A house with four people and PV panels on a time of use tariff. 3) A house with four people and no PV on a time of use Tariff - where the battery is charged at low tariff and discharged on high tariff. 4) The battery is operating as part of an aggregated frequency response system performing on the Firm Frequency Response (FFR) market. 5)The battery is operating as part of an aggregated frequency response system performing on the Enhanced Frequency Response (EFR) market. 6) The battery is operating as part of an aggregated system looking at competing in the day ahead market. This paper describes each use cases and developes a representative charge/discharge profile of these applications using MATLAB code and generates waveforms of battery charging and discharging for each use case over a year-long period in monthly intervals. Any time intervals where the battery was inactive were removed from the generation of the cycling patterns. Two statistical analysis methods (Haar transform and a pragmatic method) were used to condense the data into programmable steps for generating battery sweat testing and cycling model. These were then coded and used to generate year-long sweat testing of the different applications for use with degradation and financial analysis to look at business opportunities. This paper looks at the development of the charge and discharge profiles of these applications and defines a set of power application 'drive' cycles which are published in excel alongside this paper for use by researchers longing at battery degradation.