It’s already been two months since a number of Galaxy Note 7 units started catching fire, and now it looks like one of the major reasons why it happened was due to Samsung’s flawed design. Manufacturing company Instrumental tore down the handset and discovered that it may have been too thin for the battery.

The lithium-polymer battery inside the Galaxy Note 7 is flattened inside. But what’s more interesting to point out here is that the battery compresses inside the device even during normal operation. “The Note 7’s lithium-polymer battery is a flattened “jelly-roll” consisting of a positive layer made of lithium cobalt oxide, a negative layer made of graphite and two electrolyte-soaked separator layers made of polymer,” as explained by Instrumental.

“The separator layers allow ions (and energy) to flow between the positive and negative layers, without allowing those layers to touch.  If the positive and negative layers ever do touch, the energy flowing goes directly into the electrolyte, heating it, which causes more energy to flow and more heat -- it typically results in an explosion.”

To put it simply, the battery inside the Galaxy Note 7 didn’t have enough room inside the very thin device. The battery doesn’t have enough space inside for when it naturally swells while being used. The compression risked the chemicals inside the battery to come into contact with each other which can cause an explosion, according to Business Insider.

Instrumental’s solution to this problem is to simply put a smaller battery inside the Note 7. This would give it more room when the battery naturally swells inside the device while being used. Unfortunately, this also meant that a smaller battery will make the battery life of the Note 7 shorter.

Battery life is, of course, one of the major factors in buying a handset, and it appears as though Samsung was unwilling to compromise that. Reducing the battery size would also mean that it would have a battery life that’s shorter than its predecessor, the Note 5, and its biggest rival, the iPhone 7 Plus.

Instrumental’s discovery is just one take on the issue, and it’s possible that it’s not the only reason why the Galaxy Note 7 kept on catching fire. However, it does look like Samsung pushed its design innovation to the limit and paid the price.