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The smart meter requires a long lifetime and high reliability. Accelerated Life Test (ALT) is an important reliability acceptance method. The switch is an important human-machine interface for electricity meters, and its reliability will directly affect the reliability of the meter. In the article, scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS), and ion chromatography were used to analyze the failure mechanism and source of failure factors of the light touch switch that failed after ALT testing with the intelligent meter. The results indicate that the deionized water used in the production process of the switch is contaminated with K+ , resulting in excessive residual K+ inside the switch. In the ALT environment, water vapor enters the interior of the switch, forming a pathway between the high-voltage and low-voltage terminals inside the switch. Under the action of the electric field, K+ gradually accumulates to the lowvoltage terminals, forming potassium salts with other substances inside the switch. During the ALT cooling and dehumidification phase, the solubility of potassium salt decreases, the solvent decreases, and potassium salt precipitates. Due to the poor conductivity of potassium salts, the switch fails. The article proposes improvement methods for such failures from the perspectives of pollution source control and improving product protection capabilities, which can effectively improve the reliability of smart meters.
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