ThinkPad 700C has two backup batteries. As it is a machine from ’90s the battery is certainly drained.
One of them is a stand-by battery: P/N 44G3714 DC 3.6 45mAH
Internally, it is made with three 1/3AAA Ni-Cd batteries connected in series. These batteries are soldered together with spot welded steel plates.
The connector is a JST connector, and smaller than 2mm pitch (probably 1.25mm pitch?)