What is battery internal resistance? What is open circuit voltage?

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8/6/20232 min read

Battery internal resistance refers to the resistance within a battery. It is the total resistance of the internal components of the battery, such as the materials inside and the connecting wires. The internal resistance of a battery causes energy loss and reduces the voltage when current passes through the battery.

The presence of internal resistance in a battery is due to factors such as chemical reactions inside the battery, electrolyte flow, and electron transport within the materials. The magnitude of the internal resistance depends on factors such as the type of battery, its chemical composition, size, and operating conditions. Internal resistance is usually measured in ohms (Ω).

Open-circuit voltage refers to the voltage provided by a power source (such as a battery) when there is no load (resistance) connected in the circuit. It is the potential difference of the power source when no current is flowing through any load.

Open-circuit voltage can be seen as the strength of the internal electric field of the power source, representing the electromotive force of the power source. In the absence of a load, the open-circuit voltage is equal to the electromotive force of the power source. When a load is connected to the power source, the presence of battery internal resistance causes a voltage drop as the load current passes through the battery, resulting in the actual voltage being lower than the open-circuit voltage.

Open-circuit voltage is one of the characteristics of a power source, and it can be used to measure the power source’s ability to convert electrical energy. In practical applications, open-circuit voltage is often used to indicate the voltage of a battery, indicating the battery’s charge level or energy storage status.

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