With the continuous progress of new energy vehicle technology innovation, its battery management system (BMS) has also entered the runway of rapid development. Due to the increasing requirements of various manufacturers for packaging density, the traditional wire harness scheme in BMS has gradually been replaced by the cell contacting system (CCS) scheme. Different from the NTC temperature sensor in the wire harness, the FPC (Flexible Printed Circuit) in CCS generally adopts SMD type NTC thermistor to implement temperature monitoring of new energy battery.
Compared with wire harness, why can CCS become a popular alternative to BMS with FPC? This is because:
First, highly integrated
FPC is used to better save space and improve the internal structure of BMS. Different from the integration of multiple NTC sensors in the wire harness, the main required components of BMS can be equipped on one FPC, which can help BMS steadily move towards lightweight and intelligent direction.
Second, high bending strength
Main substrate of FPC is flexible copper clad laminate, which can be bent, wound, stacked to varying degrees according to the installation position, and the fit in BMS is extremely high.
Third, the temperature measurement component is miniaturized
Wire harness mainly uses NTC temperature sensor for real-time temperature monitoring, and the complex structure makes it difficult to maximize the space utilization of BMS. FPC adopts SMD type NTC thermistor for temperature acquisition and monitoring, its small size can be closer to the monitored unit and simplify the installation structure.
Fourth, improve automated production
Wire harness needs to be manually operated and installed, which not only has high labor costs, but also has low assembly efficiency. Use of FPC can realize automatic operation, eliminate cumbersome wire harness assembly and simplify the production process.
In summary, FPC breaks the limitations of the process and regularizes the installation layout, which is the main advantage of replacing the wire harness. The addition of SMD type NTC thermistor has increased this advantage:
First, leadless encapsulation meets assembly needs and improves FPC integration;
Second, the parameters support customization, and the size can be selected by customers to provide 0201, 0402, 0603, 0805, etc.;
Third, SMD type NTC thermistor is suitable for surface mounting, which can meet customer’s SMD needs and large-scale mass production.