Reading the help of the 7z-command by just typing "C:\Path To\7-Zip\7z.exe" gets the help with all possible arguments. Here we find the following interesting ones:
e : Extract files from archive (without using directory names)
and
x : eXtract files with full paths
Trial and error shows that the latter is the one fitting your desired behaviour without bigger effort :)
After the comment by @BadmintonCat here is the addition that will create a folder to zip everything into (use as batch script with the file as argument):
@echo off
SET "filename=%~1"
SET dirName=%filename:~0,-4%
7z x -o"%dirName%" "%filename%"
From the help: -o{Directory} : set Output directory. 7z will create the directory if it does not already exist.
