Thomas Edison was searching for a better rechargeable battery at the beginning of the twentieth century. Sadly, several nickel-iron battery drawbacks destined it to failure.
Edison Believed Electric Cars Needed Something Lighter
Edison believed electric cars needed something lighter and more durable than the lead-acid batteries then available. And so he developed a nickel-iron battery using an alkaline electrolyte rather than sulfuric acid.
Its positive electrode contained nickel compounds, while the negative electrode used iron. Potassium hydroxide provided the electrolyte.
The Idea Was Attractive. The Battery Was Robust
The idea was attractive. The battery was robust and could withstand repeated charging and discharging. It was also less vulnerable to some of the problems that affected lead-acid batteries. Little did be know his nickel-iron battery still had inherent drawbacks;
Edison Hoped To Make Electric Cars More Practical
Edison hoped his battery would make electric cars more practical. However, developing a successful design took years of experiments. Early versions suffered from leakage and problems with the materials used to conduct electricity.
Edison Improves The Design, But Drawbacks Remain
Edison improved the design, but the battery still had important drawbacks. Its voltage per cell was lower than that of a lead-acid cell, so more cells were needed to provide the same voltage. This added weight and bulk.
The nickel-iron battery was also expensive to manufacture. Its energy storage advantage over lead-acid was limited, and it required careful charging. Gas production at that time made it unsuitable for a completely sealed design.
Cold weather created another difficulty. The battery could lose a substantial amount of capacity at low temperatures, reducing its usefulness for some vehicles.
The nickel-iron battery therefore did not achieve Edison’s dream of making electric cars dominant. Nevertheless, it found useful applications in industrial equipment, railway systems and standby power.
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