Woocommerce plugin is translated independent from theme strings.
Download the already translated .po file from the translate.wordpress.org manually
, first go to https://translate.wordpress.org/projects/wp-plugins/woocommerce and look for your language in the list. Click on the title to go to the section for the language. Export the .mo file to use on your site.
Rename it according to your language. Example: ‘woocommerce-pt_DE.po’ for German language. Edit the file with POEDIT, translate the words to your need and save. After saving it will generate the ‘woocommerce-pt_DE.mo’. Copy these two files at your wp-content/languages/woocommerce (create the folder first if it is not present).