@echo off
:::::::::パターン1:::::::::
SETLOCAL ENABLEEXTENSIONS ENABLEDELAYEDEXPANSION
for /F "tokens=3" %%i in ('vol c: ^| findstr /C:シリアル番号') do (
	set work=%%i
	set work=!work:-=!
	echo %work%
)
ENDLOCAL

:::::::::パターン2:::::::::
for /F "tokens=3" %%i in ('vol c: ^| findstr /C:シリアル番号') do call :test %%i
goto :EOF

:test
set work=%1
set work=%work:-=%
echo %work%
goto :EOF