Question Laptop battery substitute

Jul 25, 2020
I call this battery substitute. I'd like to hear some ideas about a battery problem. This is the 2nd battery I am buying and it isn't charging. The charger works fine without a battery connected. This is an HP Elitebook 8570p. The utility reported for the 1st battery and the 2nd that the first cell is dead. The problem is that the battery just doesn't charge. What I am thinking is that the part of the connector that transmits power from cell 1 is bad.
So, to come back to my question: I have been looking at power banks and connecting via usb-c (which I do have on the laptop). But when such a product is described, it talks about charging the laptop. So wouldn't that mean that the battery would again be involved?
Sure, I can always turn off the computer, then turn it back on at a different wall plug-in. But what other options do I have if I want to use my laptop in a portable way, without connecting it to AC?
I do not want to get rid of this laptop. I like it.