It is critical for thermodynamics, the most difficult branch of physics, to be reformed and updated. Through the analogy between thermodynamics and electricity, the concepts of thermal charge and quantity of thermal charge were introduced in an intuitive way, from which a simple yet explicit definition was derived——entropy is the quantity of thermal charge. As a result, the two quantities, i.e. entropy (quantity of thermal charge) and the quantity of heat can be clearly distinguished. This eliminates not only the abstractness of thermodynamics but also the fuzziness of the original concept of entropy. These new ideas for thermodynamics are expected to make it easier for our scientists and engineers to understand, apply and innovate, and therefore to enhance China's soft power in science and technology. Also, it should be beneficial to our physics teaching in both universities and high schools, as well as to the popularization of thermodynamic knowledge.