Chinese batteries and electric vehicles maker BYD Company Ltd (<a href="https://www.hkex.com.hk/Market-Data/Securities-Prices/Equities/Equities-Quote?sym=1211&sc_lang=en" target="_blank">HKG:1211</a>) announced today that BYD Energy Storage recently signed what is described as the world's largest grid-scale energy storage supply deal with Saudi Electricity Company.