Battery Day (Denchi no Hi)

What Is Battery Day?

November 11th is "Battery Day" (Denchi no Hi) in Japan, established in 1986 by the Japan Dry Battery Industry Association, the predecessor of today's Battery Association of Japan. Written in kanji numerals, the date looks like a run of plus and minus signs (the character for ten resembles a plus, and the one for one a minus), which stand for the positive and negative poles of a battery. Batteries power remote controls, clocks, flashlights, and much more. Precisely because they are so familiar, it is a good day to check how you use them.

The Battery Association and "Battery Month"

The Battery Association of Japan was formed in 1997 through the merger of the Japan Storage Battery Association, founded in 1938, and the Japan Dry Battery Industry Association, founded in 1942. It works on the healthy development of the battery industry and related fields, including standards and the recycling of used batteries.

• Battery Day:November 11th, a date that resembles a battery's positive and negative poles
• Battery (Baseball) Day:December 12th. In baseball, the pitcher is position number 1 and the catcher is number 2, and together they form the "battery," giving the date 1 and 2
• Battery Month:The period from Battery Day to December 12th. It was set in 1997 as a chance for people to review how to use batteries correctly and safely

Sakizo Yai, Inventor of the Dry Cell

The first person to make a battery in Japan is said to be Shozan Sakuma, in the late Edo period. Batteries then were "wet cells" using liquid electrolyte, which needed care and could freeze in cold places. The man who solved this and completed a dry cell in 1887 was Sakizo Yai, from Nagaoka in Niigata. By soaking carbon rods in paraffin, he made a battery that was less prone to leaking and easier to carry. Its usefulness in cold regions was recognized during the First Sino-Japanese War, and it became widely known. Japan's first dry-cell patent is said to have gone to Ichisaburo Takahashi.

Tips for Marking This Day

• Check the batteries in remotes, wall clocks, and other devices with no power switch. The Battery Association notes that such devices keep draining their batteries, so they should be replaced regularly
• When you change batteries, replace them all with new ones at once. Do not mix new and old batteries, or different types such as alkaline and manganese
• Remove batteries from devices you are not using, and take out used-up batteries. This keeps leaks from damaging the equipment
• Tape over the terminals of used batteries before throwing them away, and follow your local rules

Types of Batteries and Disposal Basics

Generally, alkaline batteries suit high-drain devices, while manganese batteries suit low-drain ones such as remotes and clocks. Dry batteries cannot be recharged; charging them can cause leaks and heat. Mercury is no longer used in dry batteries made in Japan (since 1991 for manganese and 1992 for alkaline). An estimated 34,000 tons of used dry batteries were generated in 2021, and most are collected and processed by local governments. Button and rechargeable batteries have dedicated collection systems, so check with the store where you bought them or with your local government. Coin lithium batteries can cause serious accidents if a small child swallows one, so keep them out of reach.

Summary

Battery Day is a day to review how we use and dispose of batteries we rarely think about. Keep checking the batteries around you through December 12th, the end of Battery Month. Battery history is said to begin with the voltaic pile invented by Italy's Alessandro Volta in 1800, and the unit "volt" is named after him.