Introduction

One of the most commonly used battery type in traction application is the LiFePO₄ cells. These batteries are suitable for supply energy in wide temperature range and ensure long lifetime. Although the cell properties provide safe operation for customer the application has to avoid the operation outside of safe operation area. For this purpose our management system gives a customer friendly, cost efficient, flexibly mountable battery data collection and management operation. The BMS is designed for railway application, used together with high frequency IGBT converters. Besides supervision of battery operation the BMS carries out the cell balancing function as well.

BMS description

Sedulitas-Pro’s BMS is based on three base units, like measuring node, gateway and BMS centre. Thanks to the well-proven CAN and LIN communication application the system components can be fitted to each other and to the outside controllers. Concerning topology the three base parts are the followings:

• Measuring node is suitable for measure two cells’ parameters. One node is mounted on two serially connected cells and measures the voltages and temperatures of them, further actuates the shunt resistors by means of built-in FETs.
• Gateways are the data collector and connection medium between nodes and BMS centre. Via LIN net it keeps connection to maximum 15 pieces of nodes, organizes the data and forwards toward the centre through CAN line.
• BMS centre is the head of supervising system. This equipment keeps contact with maximum 32 pieces of gateways further with superior controller via CAN or SAE network. The BMS centre contains the all battery related calculations, protection functions, charging-discharging conditions and balancing control. By means of diagnostic surface the cells can be checked via a standard portable PC.

BMS diagnostic

Diagnostic softwareBy the diagnostic software each cell voltage and temperature can be followed in the configured amount, further the shunt states as well. In case of necessity the trained staff is allowed, after using special password, to actuate shunts manually or set some parameters like SOC initial value.

In diagnostic software the cells are grouped by gateways, thus in one window maximum 30 cells can be checked in same time. During technical agreement with Customer modifications can be carried out on diagnostic surface in accordance with Customer’s wish.