P&G announced in 2014 that Duracell would become the first of up to 100 brands to be axed from its portfolio, as part of a strategy to focus on more profitable brands in fewer market segments.
The brand was bought that November for $4.7bn (£3.36bn) by Warren Buffett’s Berkshire Hathaway, which had previously been a major shareholder in P&G.
Jouanneau said the process of separating has taught her that certain things are vital for a brand to hold on to – while others can be left behind.
"Carving out a brand is like moving home," she said. "Home, not house – the difference is something built with the heart and not just with the hands."
Moving meant accepting that "something will get broken on the way", Jouanneau said, and a marketer’s job is to ensure that valuables are protected.
"Start with invaluable items, what money can’t buy. For the brand – it is about brand character, it is the brand soul, the tone of voice. At Duracell, we have the Bunny. It was vital for me to protect him during the move."
On the other hand, an ownership change also presented an "opportunity to declutter", she said.
"Be ruthless. Decide which projects to exit. Have the courage to shrink. At least 30% of your brand activities could be historical accumulation."
The sale of Duracell completed in March 2016, just a few months after the brand began a partnership with Disney that has continued to the present and spanned all the media giant’s key properties: Disney Animation Studios, Star Wars and Marvel.
The latest output of the partnership is a new ad (above), created by Grey London - which won the global account for the brand in 2012 - featuring both Marvel’s Iron Man and the Duracell Bunny, that highlights the brand’s suitability for toys.
The campaign is launching in around 80 markets, though these do not include North America, where historical reasons mean the character is owned by rival Energizer (a situation that led to a court case in 2016).
Disney wasn’t just a valued partner because of the obvious synergy between movie characters, toys and batteries, Jouanneau said – the two also share priorities. "We do safeguard our assets very much, and Disney is another company that puts a high premium on protecting its assets," she said.
"It’s also the Bunny character. He needs to be comfortable in those worlds; they need to be contemporary and innovative."
Some commentators have suggested that batteries are one of the product categories that stands to be most thoroughly disrupted by changing consumer behaviour, especially the advent of voice technology – with both Duracell and Energizer having been overtaken in online sales in 2016 by Amazon Basic batteries.
But Jouanneau is not concerned about the apparent threat: "Duracell is a big and popular brand. The Duracell Bunny is a lovemark and we continue to create top of mind awareness. The brand strategies we implement keep the brand fresh and modern.
"My belief is that the era of voice shopping will give even more prominence for big and popular brands. I see it as the ‘acid test’ for brand building, and the big and popular brands like Duracell will be named."