There’s a saying from the brick-and-mortar world that to understand something fully, means ‘having it taped’. In those days people used to physically record sound on reel-to-reel audio though. We heard researchers at Dalhousie University, Canada have a way of getting battery self-discharge taped. Although getting it un-taped would be closer to the truth.
Finding Battery Self-Discharge in the Tape
Battery self-discharge can be one of the most irritating aspects of portable electronic devices. We charge our laptop fully before we leave on business, only to find it partly-discharged when we arrive. However, until now we had to put up with the inconvenience, because feeling frustrated hardly helped.
But that might be before researchers at Dalhousie removed a piece of adhesive tape from inside a cellphone, and made a remarkable discovery. We didn’t know if before, but apparently this tape keeps electrodes in place during phone assembly. We’ll let assistant professor there Michael Metzger take up the story.
We were on the path to getting battery self-discharge taped, he explains. And we were opening cases to expose the workings to different temperatures when we noticed their electrolytes were different colors, which was not supposed to be the case. So we decided to investigate to take the batteries apart to find out why.
How the Tape Explained Self-Discharge
The Dalhousie scientists investigated further. They opened more cellphones and placed these in ovens at different temperatures:
- The electrolytes stayed clear at 25C
- But became light brown at 55C
- While they were bright red at 70C
Intrigued, the researchers analyzed the electrolytes. They discovered the presence of polyethylene terephthalate in them. This is the active ingredient in the PET tape holding battery electrodes in position, and behind the redox reaction causing the battery self-discharge.
“It’s something we never expected, admits assistant professor Michael Metzger. “Because no one looks at these inactive tapes and plastic foils in battery cells”. Although it seems a useful clue to getting battery self-discharge taped, to us.
More Information
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Preview Image: Different Phones What’s Inside?
