system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How are non-rechargable batteries pre charged before they are sold?
gpt
Non-rechargeable batteries are not “charged,” they’re simply constructed. Non-rechargeable batteries use a chemical reaction to generate an electrical potential. The chemical properties of the battery’s internal materials are therefore different before and after they are depleted. They are constructed with materials in their “pre-use” chemical state, which naturally form a voltage. 

Think of it this way: recharging batteries is like stretching a spring, storing energy within the system. Non-rechargeable batteries are like building a pre-tensioned spring, with the potential energy already in place. Once the energy is expended, the spring is collapsed, and you grab a new one.

Edit: Just to clarify, some “springs” are re-stretchable (re-chargeable batteries), and some are not. This depends on the type of chemical reaction in place. Some chemical reactions yield electrical potential with the ability of applied electrical potential to reverse the reaction. Others are one way only.