Stack Switch Functions - Nuvation Energy NUV300-BC-12 Product Manual

1. During connection or disconnection of the battery to prevent harmful transient current events
2. During operation of a connected battery to keep the battery within its operational limits
3. During operation of a battery to keep the individual cells at a balanced state of charge
4. During a fault condition in order to protect the battery
Control for cases (1) and (4) is achieved through external switching devices that are under the
control of Nuvation Energy BMS. This control is limited to hard switching. Control for case (2) is
achieved through current limiting signals that are used by chargers and inverters to throttle current
dynamically. Control for case (3) is implemented within Nuvation Energy BMS itself through passive
balancing loads that are under control of a configurable balancing algorithm.

7.6.1. Stack Switch Functions

Nuvation Energy BMS defines three contactor switch functions for use within typical battery
configurations:
▪
Pre-charge Switch: Connected during pre-charge operation only. Disconnected under fault
condition.
▪
Main Switch: Connected after any pre-charge operation completes. Disconnected under fault
condition.
▪
Stack Switch: Connected whenever either the pre-charge switch or the main switch is
connected. Disconnected under fault condition.
While a pre-charge contactor is optional, virtually all systems require a main contactor to protect the
battery from unsafe conditions. A stack contactor is often used in conjunction with a main contactor,
i.e. at the other end of the stack to isolate the battery stack completely from the DC bus and provide
a level of contactor redundancy.
Stack connection and disconnection sequencing is illustrated in the state diagram below.
Document ID: NE-PM-002
Figure 73. Battery Stack States and Transitions
Nuvation Energy Low-Voltage BMS - Product Manual
105 Rev 1.2, 2021-03-03
Curie Update 1