iPhone 6 Plus Overheating soon as the battery plugged

Hello, i am having a bit of a problem with my iPhone 6 Plus, so this problem occurs for 2 weeks ago, and it got so warmed that the Overheating notification pops up, and i left it for a while, but for 6 hours more, it doesn’t disappear, it did when the battery ran out completely.

2 Days ago, i am having a problem with my LCD, it became untouchable, and when i go to my repair shop, they told me that the IC touchscreen is damaged, and the battery needs to be changed. After changing all of it, i brought it home, and works fine. but after 30 mins of turning it back on, the problem reoccurs.

i got fed up, and i stripped my phone, and found out that the problem is this part.(blue marked)

when i plugged in the battery, it instantly become hot, even too hot to be touched by hand. Can you tell me what could be the problem ?