(Yicai Global) Oct. 16 -- Since its release last month, Apple Inc.'s [NASDAQ:AAPL] iPhone 8 has been the recipient of at least 10 complaints in which the smartphone battery has expanded and cracked the phone's shell open.

The bulk of the problems have occurred in Greater China, one of the firm's biggest markets, where the problem has occurred at least five times, Beijing Daily reported on Oct. 14. Reports of the issue have also come in from the US, Japan, Canada and Greece.

Expanding batteries have caused these phones to burst at the seams along the phones edges, despite having never been used. The use of glass in the phone's structure could be partially blamed, an industry analyst said, though glass is useful for wireless charging, it can't handle the pressure as well as metal.

The source of the problem is the lithium battery itself, which can be affected by external temperature changes, the analyst said. Apple claims that as the phone is just cracking open, and the battery isn't exploding, it's not a major safety concern. It is still investigating the problem.

The smartphone maker has replaced the problem phones free of charge, but users are questioning the firm's wireless charging technology, the report said. Apple has recently been losing its foothold on the Chinese market, and this latest problem is unlikely to help its attempts to recover.