If they are directly connected, une fois qu'ils rencontrent l'électrolyte formé par l'eau, dioxyde de carbone et autres impuretés, une batterie chimique sera formée. This is because aluminum is easy to lose electrons to become a negative electrode, and copper is difficult to lose electrons to become a positive electrode. An electromotive force of 1.69V is formed between, and a small current passes through, which corrodes the aluminum wire, which is the so-called galvanic corrosion. This will cause poor contact between copper and aluminum and increase the contact resistance. When a current passes through, the temperature of the joint will increase, which will further accelerate the corrosion of the joint, increase the contact resistance, and cause a vicious circle until it burns out.
