Battery Junction Box

WARNING: This page is about a different car, the 2016 Infiniti Q50. However, it is still accessible from the selected car via links, so may be relevant.

The battery junction box is installed inside the battery pack.

Courtesy of NISSAN NORTH AMERICA, INC.
The battery junction box contains the system main relays for supply of DC electrical power from the Li-ion battery, as well as the current sensor which measures the DC current.
A system main relay is installed on both the positive side and negative side. They supply DC power to the high-voltage components. They also supply DC power to the Li-ion battery during motor regeneration and charging.
When a system malfunction occurs, the system main relays immediately turn OFF based on the command from the HPCM (Hybrid Power-train Control Module), shutting off the Li-ion battery in order to ensure safety.