Acid from the 10p-sized cell burned through her stomach and main arteries of two-year-old Kacie Barradell, leading to a six-hour operation.
Kacie has spent a total of eight weeks in hospital with her parents being warned she might be paralysed from the waist down.
Her oesophagus is so badly burned she cannot eat or drink and is currently being fed through a tube.
Kacie’s mother Cheryl Bell, 27, has been told it could be at least a month before her daughter is able to go home.
She said: “I’m going through hell and back. Kacie might not walk again for the rest of her life.
“She could have died and she would have if it hadn’t been for them.
“I want to get the message out there about how dangerous button batteries are.”
Sheila Merrill of the Royal Society for the Prevention of Accidents said: “Young children are naturally inquisitive, and explore the world in part by putting things in their mouths.
“As more and more electronic items are introduced into the family home, the potential for children to swallow button batteries increases, and this can lead to choking or poisoning.
“We want parents, grandparents, childminders and carers to be aware of the danger and understand that these seemingly harmless little batteries can cause serious injury to children.”