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Energy Management System (EMS) is a vital part of a Li-ion battery system, in order for the battery system to achieve safety, performance and longevity. Our EMS system is designed to work seamlessly with GBS Li-ion batteries. It is designed and built in the U.S.A. The EMS system monitors the conditions of all battery cells within the pack, protects the cells from undesirable conditions, detects ground fault condition and provides pack level and cell level information through video display and CAN communication.
Key features of the EMS system:
- The EMS system is a distributed system using daisy chain structure, in order to avoid messy wiring and to achieve accurate data acquisition.
- The system is scalable, and it can support voltage of battery pack up to ~450V.
- The system incorporates noise filtering strategy to address electromagnetic interferences (EMI).
- The systems measures voltage and temperature of each battery cell.
- Cell balancing function is built into cell sense boards.
- Ground fault detection is integrated into the system.
- The system measures pack current and calculates State-of-Charge (SOC).
- Alarm reporting includes high and low cell voltage alarms, high and low cell temperature alarms, high current alarm.
- It supports composite video output and CAN communication output.
Components of an EMS system:
CPU (one required)
This is the central hub of the system. It receives information from the sense boards, measures pack current and voltage and calculates State-of-Charge (SOC). It provides high and low cell voltage alarm interlocks and can detect ground faults. A composite video output is standard.
CAN board (optional)
Controller-Area-Network (CAN) protocol is a standard communication protocol commonly used for data communication within a vehicle. An optional CAN board can be installed to the CPU in order for the CPU to broadcast pack data, cell data and alarm status to external devices.
Sense board strings (required and scalable)
Each sense board strings contains four sense boards for a 4-cell pack. The sense board strings can be linked together to form a daisy chain to support a larger battery pack. Each sense board on a 4-cell string measures voltage and temperature of the respective battery cell. Cell balancing function is built into the sense board. We have two versions of 4-cell strings: V2 and V6. V2 strings are suitable for smaller battery pack, i.e. 16-cell pack or smaller. V6 strings are suitable for larger battery pack up to ~140 cells.
CPU cable (one required)
CPU cable connects between the CPU and the first Sense Board String.
Extension cables (optional)
When there are sub-packs located not immediately adjacent to each other, an extension cables can be inserted at any point within the daisy chain. They come with 1-ft, 3-ft and 10-ft lengths.
Shunt (one required)
Shunt is a precision low value resistor which is used for pack current. Wire connections need to be established between the CPU and the shunt per installation instruction.
LCD video screen (optional)
Pack level information including pack voltage, pack current, State-of Charge (SOC) and alarm status, as well as cell level information, can be displayed on a LCD video screen. The LCD video screen needs to be powered by a 12V source, and a standard RCA video cable (not provided) connects between the CPU and the screen.
This document was last updated on August 12th, 2013
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EMS Operation Manual
EMS System Setup Guide
EMS CANBUS Specification
EMS MODBUS Specification
Cell Balancer Specifications
Low Voltage Disconnect Specifications
EMC Series Charger User Manual
EVC Series Charger User Manual
GBS Cell Charging/Discharging Curves
Cycle Life Testing of a GBS Cell
Vehicle Range vs Speed