Step 1: Definition of an ideal battery.
An ideal battery is one that provides a constant potential difference (voltage) without any internal resistance. No energy is lost as heat, so no thermal energy is developed when charge flows through it.
Step 2: Analyze the options.
- Ideal dielectric: a material that doesn’t conduct charge.
- Ideal capacitor: a perfect capacitor with no losses or imperfections.
- Ideal resistor: a resistor with no internal heat dissipation (not possible in real life).
Step 3: Conclusion.
The battery that does not develop any thermal energy when charge flows through it is called an ideal battery.
Final Answer:
\[
\boxed{\text{an ideal battery}}
\]