What device consists of two or more cells and converts chemical energy into electrical energy?

Batteries are devices that consist of two or more electrochemical cells connected together to generate electrical energy. Each cell within a battery typically contains a chemical electrolyte and electrodes that participate in redox (reduction-oxidation) reactions, converting stored chemical energy into electrical energy when a circuit is completed. The essential operation of a battery relies on these chemical reactions, allowing it to supply power to various devices.

In contrast, capacitors store electrical energy temporarily and release it when needed, rather than converting chemical energy to electrical energy. Generators convert mechanical energy into electrical energy but are not based on chemical reactions. Transformers, on the other hand, are designed to transfer electrical energy between two circuits through electromagnetic induction, playing no role in the conversion of chemical energy. Hence, the accurate identification of batteries as the correct answer emphasizes their fundamental role in energy storage and conversion specifically based on chemical reactions.