How do you remove the car battery of 2001 Volvo s40?

I don't know, but I had a similar problem in a 2002. It seemed there was a latch that was supposed to slide to let the battery out which was latched in, but I couldn't move the latch at all. It was very frustrating and a person from Checker Auto Parts couldn't figure it out either.

I had similar situation, after some frustrating time trying to figure out how to release the latch, it occurred to me that the latch is designed to pop-out when levered upward at the tap. I used a hammer claw to tug at the tap of the latch and pull upward with controlled steady force, and it should pop-out.