Design And Development Of Power Battery Management System Of Passenger Vehicle Based On Functional Safety

The new energy vehicle industry development plan(2021-2035)(Draft for comments)has been proposed,which shows that the sales of new energy vehicles will account about 25% until 2025,and the domestic public domain vehicles will be fully electric until 2035.In recent years,new energy vehicles have been vigorously promoted under the guidance of policies.The development of electric,intelligent,networking and sharing requires more and more integration of BMS,and the high complexity brings more and more security problems.At present,the level of battery management system design and development in the market is uneven and there is no unified design standard,so it is particularly important to jointly promote a set of safe and reliable development and design process.Based on a battery management system development project of an automobile enterprise,a safe and reliable battery management system is designed and developed according to ISO 26262 "road function safety standard",which has been verified in a real vehicle.As the management module and insulation detection module of high-voltage power on and off are two modules in BMS which involve more complex logic and higher functional safety,it is highly representative to select these two modules for development and design.The design process first obtains the safety objectives and ASIL level from hazard analysis and risk assessment,then determines the functional safety requirements and technical safety requirements,defines the system architecture,allocates the technical requirements to hardware and software,and finally designs and verifies the software and hardware.The verification shows that the design meets the requirements of functional safety,functional safety and reliability,which can provide reference for the development of battery management system.The main works are as follows:(1)Complete the design of BMS development process based on functional safety.Through the research on the international standard ISO 26262 functional safety,the concept of functional safety is applied to the development of battery management system,and a set of design and development process of battery management system based on functional safety is made,which provides substantive reference for the current situation that the design process and reference standards of major BMS suppliers and vehicle enterprises in the market are uneven.(2)Complete the requirement analysis of typical functional modules based on functional security development.Based on the development and design process of functional safety,the requirements of high-voltage power on and off management module and insulation detection module are analyzed.Based on the definition of relevant items,the paper completes the Hara analysis of BMS,and then,according to the Hara analysis,derives the design scheme and technical safety requirements specification of relevant functional safety concepts,and designs the BMS software architecture scheme.(3)Complete the software strategy design and modeling of battery management system application layer.First,the related software technical requirements are made into the corresponding strategy flow chart,and then the corresponding software model is established in the MATLAB / Simulink / stateflow software environment.Finally,the model generated code is compiled at the bottom and written to the main control board through boot brush for software debugging and verification.(4)The simulation model of modular application layer and real vehicle verification are established.Complete the building of BMS related simulation modules and unit test verification,complete the integration test verification based on the main board and upper computer,complete the bench and real vehicle test verification,and finally achieve the mass production requirements.