I have been looking at a lot of Battery management system/protection circuits lately and there are components that I can't identify. Can anyone tell what is the name and function of the component I encircled in the image? I am thinking that that these are fuses but I might be wrong.
Those look like bus bars to me -- essentially very low-resistance, high-current capacity interconnects commonly found on a PCB. In a battery pack, especially one capable of hundreds of amperes, the difference between a 1mOhm and 2mOhm could be 10W dissipated vs. 20W dissipated.
The wires you see are probably not copper but a material chosen for temperature invariance .It could be manganon or phosphor bronze or some alloy designed to hopefully have a near zero temp co of resistance .These materials have much more resistance than copper .Copper has a significant tempco like most metals.The voltage developed across the shunt can now accurately be used for current measurement as long as the currents are not too small where opamp offsets would spoil things .Its all a comprimise because low resistance means low losses and higher resistance gives better low end accuracy .This is why the better equipment uses the more expensive hall effect devices.