Dim objExcel As New ExcelPackage
Dim Sheet As ExcelWorksheet = objExcel.Workbook.Worksheets.Add("SheetName")
Sheet.Cells["A1"].Style.Fill.PatternType = Style.ExcelFillStyle.Solid
Sheet.Cells["A1"].Style.Fill.BackgroundColor.SetColor(Color.FromArgb(170, 170, 170))