Can capacitors explode?
Capacitor plague
At the beginning of the 1990s, some Japanese manufacturers started the development of a new, low-ohmic water-based class of electrolytes. Water, with its high permittivity of ε = 81, is a powerful solvent for electrolytes, and possesses high solubility for conductivity-enhancing concentrations of salt ions, resulting in significantly improved conductivity compared to electrolytes with organic solvents like GBL. But water will react quite aggressively and even violently with unprotected aluminum, converting metallic aluminum (Al) into aluminum hydroxide (Al(OH)3), via a highly exothermic reaction that gives off heat, causing gas expansion that can lead to an explosion of the capacitor. Therefore, the main problem in the development of water-based electrolytes is achieving long-term stability by hindering the corrosive action of water on aluminum.
Parasitic capacitance
When two conductors at different potentials are close to one another, they are affected by each other's electric field and store opposite electric charges like a capacitor. Changing the potential "v" between the conductors requires a current "i" into or out of the conductors to charge or discharge them.
where "C" is the capacitance between the conductors. For example, an inductor often acts as though it includes a parallel capacitor, because of its closely spaced windings. When a potential difference exists across the coil, wires lying adjacent to each other are at different potentials. They act like the plates of a capacitor, and store charge. Any change in the voltage across the coil requires extra current to charge and discharge these small 'capacitors'. When the voltage changes only slowly, as in low-frequency circuits, the extra current is usually negligible, but when the voltage changes quickly the extra current is larger and can affect the operation of the circuit.