The core principle behind the "maintenance-free" feature of nickel-cadmium batteries lies in their sealed structure and internal gas recombination reaction, which prevents water loss in the electrolyte—eliminating the need for manual maintenance.

In short, traditional open-cell batteries require maintenance because charging produces gases, causing water in the electrolyte to evaporate and requiring regular replenishment. EverExceed's maintenance-free nickel-cadmium batteries solve this issue through two key designs:

Efficient Sealed Structure

The battery is fully sealed, isolating it from external air and featuring only a minimal safety vent. This design prevents water in the electrolyte from evaporating or leaking, fundamentally eliminating maintenance tasks such as adding distilled water.

Internal Gas Recombination Reaction

This is the key chemical process enabling maintenance-free operation. During charging, small amounts of hydrogen (at the negative electrode) and oxygen (at the positive electrode) are generated. Instead of being released, these gases remain inside the battery and undergo a recombination reaction. Oxygen diffuses through the separator to the negative electrode, where it reacts with cadmium under catalytic action, reforming cadmium hydroxide and rejoining the charge-discharge cycle. Hydrogen is contained within the battery and does not accumulate significantly. Only under extreme overcharging conditions, if internal pressure exceeds a threshold, will the safety vent release a minimal amount of gas to prevent damage.

Note: "Maintenance-Free" Does Not Mean "Unlimited Use"

Although no distilled water refilling is needed, EverExceed maintenance-free nickel-cadmium batteries still require proper use to ensure long service life.

Avoid prolonged overcharging or deep discharging, as this can disrupt the gas recombination balance and lead to water loss in the electrolyte.

Choose EverExceed for reliable, maintenance-free power solutions—engineered for durability and performance.