Stack SwitchgearNuvation Energy’s Stack Switchgear (SSG) provides an integrated battery stack management solution that includes all the hardware and software required to integrate a battery stack into your energy storage system (ESS). Each SSG unit contains Nuvation Energy battery management system modules and is designed to be used with other products in the Nuvation Energy battery management system family.

SSG configurations can vary depending on your system requirements, providing more or less functionality as needed to match your needs. Standard configurations support up to 1000 V or 1250 V, and 150 A or 300 A per stack. Non-standard configurations are available on request. (User Manuals and Technical Resources)

Features

Battery Stack Management

  • Connects and disconnects a battery stack to the DC Bus of the ESS in response to requests from system controllers. Will also report the resulting capacity change to the PCS and other energy management systems.
  • Provides battery stack terminal connections as well as communications I/O for other ESS controllers.
  • Receives voltage and temperature data from Nuvation Energy’s Cell Interface BMS modules (sold separately) that are connected to the cells. Provides cell balancing commands to those modules during the charge cycle.
  • Calculates State of Charge (SoC) and Depth of Discharge (DoD) and uses voltage and temperature data from the BMS to determine safe current thresholds. Provides those current thresholds to the power conversion system, which uses this information to regulate charge and discharge currents.
  • Executes safety disconnect commands from the BMS to protect the battery if cell performance thresholds (i.e. temperature, voltage, SoC, DoD) have been exceeded. Also includes over-current as well as short-circuit protection.
  • Can control battery module cooling fans in response to temperature data from the BMS.

Multi-Stack Battery Management

In energy storage systems that contain multiple battery stacks connected in parallel to increase capacity, one SSG unit manages each stack. All Stack Switchgear units and battery stacks can be managed together by a Nuvation Energy Grid Battery Controller, which aggregates the stacks and manages them as a single battery. The Grid Battery Controller also enables communication between the BMS modules and other system controllers within the energy storage system, and intelligently automates the sequence in which stacks are connected to the DC Bus.

Stack Switchgear Diagram
One SSG manages one series-connected battery stack. Parallel battery stacks are aggregated and managed as a single battery using a Nuvation Energy Grid Battery Controller (GBC).

Configuration Options

Included With all Stack Switchgear

  • Battery Management System - All Nuvation Energy Stack Switchgear units include the Stack Controller (SC) and Power Interface (PI) module required to manage the stack. The Stack Controller measures State of Charge (SoC) and State of Health (SoH) at both the stack and individual cell levels, and makes current limit threshold data available to the power conversion system and other system controllers. The Power Interface provides power to all other BMS modules, and measures stack current. It also includes built-in coil drivers that energize and de-energize the contactors.
  • Pre-Charge Resistor - includes a pre-charge resistor and contactor that protect the battery stack from a voltage mismatch between the stack and DC bus by allowing the BMS to test for a safe voltage match prior to connecting the stack. This also protects inverters and power conversion systems that do not include their own pre-charge circuits, by allowing the battery stack to safely charge the internal capacitance of the PCS prior to stack connection.
  • ContactorsStack SwitchgearStack Switchgear includes contactors that connect and disconnect the battery stack to the energy storage system. The battery management system also uses these contactors to disconnect the stack to protect the battery if voltage and temperature thresholds are exceeded for any reason.
  • Fuses, Bus Bars, Current Shunt, Connectors, Communications I/O – Stack Switchgear includes everything you need to integrate your battery stack into your energy storage system.

Optional Components

  • AC Power Supply Input – The default Stack Switchgear configuration receives power from an external 24 VDC source. However, an energy storage system developer may choose to also request support for an AC 120 V or 240 V power input. 
  • Black-Start Capable – Sources power for the SSG from the battery stack to allow the ESS to be brought online and operate without a grid-tied connection.
  • Manual Service Disconnect Switches – Two “Lock Out, Tag Out” (LOTO) manual disconnection switches can be included in the SSG, to enable the stack to be manually taken offline for servicing.
  • E-Stop Input – Each SSG unit can include inputs for the connection of an external Emergency Stop signal in the ESS that will trigger a BMS Fault to disconnect the battery stack.
  • Fan Control – The SSG enables the battery management system to control fans that draw heat away from the battery modules when cell temperatures have been exceeded.

Contact us for more information about Nuvation Energy’s Stack Switchgear, or to discuss how Nuvation Energy can help with your energy storage system project.