Automotive Battery Management Solution

Application

Description

Comprehensive battery management system solution using AutoChips MCUs and sensor interfaces for electric vehicle and energy storage applications.

Core Advantages

Precision Measurement High-resolution ADC and precision reference enable accurate cell monitoring
Fast Fault Response Hardware protection circuits respond within microseconds to over-voltage and over-temperature conditions
ISO 26262 Support Complete safety documentation and software support for functional safety compliance
Communication Flexibility CAN-FD and isolated SPI interfaces support various BMS architectures
Temperature Management Multi-point temperature monitoring enables intelligent thermal management

Recommended Bill of Materials (BOM)

Item Part Number Description Quantity Datasheet
1 AC78406 ASIL-D MCU for BMS control and safety monitoring 1 📄 Download
2 AC7840-SENSOR High-precision sensor interface for cell voltage/temperature 4 📄 Download
3 AC7840-PMIC Safety PMIC for redundant power supply 1 📄 Download

Applications

Electric Vehicle Battery Packs
Hybrid Vehicle Energy Storage
Stationary Energy Storage Systems
48V Mild-Hybrid Systems
Industrial Battery Systems

Technical Specifications

Cell Voltage Accuracy
±1mV
Temperature Accuracy
±0.5°C
Cell Count
Up to 16 cells per module
Balancing Current
Up to 200mA active balancing
Communication
CAN-FD, isolated SPI

Customer Success Stories

Electric Vehicle Startup (Anonymous)

Electric Vehicles |

Challenge

Required ASIL-C BMS for 400V EV battery pack with 96 cells. Needed high accuracy monitoring and fast fault response for safety certification.

Solution

Implemented modular BMS using AC78406 ASIL-D MCU and AC7840-SENSOR interfaces. Designed active balancing system with 150mA balancing current. Developed ISO 26262 compliant software with comprehensive diagnostics.

Results

Energy Storage Company (Anonymous)

Energy Storage |

Challenge

Required BMS for 100kWh grid-scale energy storage system with 280 cells. Needed high accuracy monitoring and modular architecture for scalability.

Solution

Implemented distributed BMS using AC78406 ASIL-D MCU and AC7840-SENSOR interfaces. Designed modular system with 14 modules of 20 cells each. Developed active balancing system with 200mA capability.

Results

FAE Expert Insights

S

Senior FAE

Applications Engineer

10+ years

Professional Insights

Battery management system design requires careful attention to measurement accuracy, safety, and reliability. The most critical aspect is cell voltage measurement accuracy - even small errors in cell voltage can lead to significant SOC estimation errors and reduced battery performance. I always recommend using 24-bit ADCs with precision voltage references for cell monitoring. Another critical consideration is fault response time - battery faults can escalate quickly, so hardware protection with fast response is essential. The AC7840x series provides both high-accuracy measurement and fast hardware protection. For thermal management, distributed temperature monitoring with multiple sensors per module provides better insight into battery thermal behavior. Cell balancing is often underestimated - passive balancing is simpler but wastes energy, while active balancing improves efficiency but adds complexity. For large battery packs, active balancing often pays for itself through improved capacity utilization.

Key Takeaways

  • Use high-resolution ADCs for accurate cell voltage measurement
  • Implement fast hardware protection for critical battery faults
  • Deploy distributed temperature monitoring for thermal management
  • Consider active balancing for large battery packs
  • Follow ISO 26262 for functional safety compliance

Decision Framework

BMS Solution Selection Framework
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Frequently Asked Questions

What cell voltage accuracy is required for BMS applications?

Automotive BMS applications typically require cell voltage measurement accuracy of 1-5mV for proper SOC and SOH estimation. The AC7840-SENSOR provides 1mV accuracy with 24-bit ADC. Higher accuracy enables better battery management and longer pack life.

Select measurement hardware providing at least 5mV accuracy, preferably 1mV.

What is the difference between passive and active cell balancing?

Passive balancing dissipates excess cell energy as heat through resistors. Active balancing transfers energy from high cells to low cells. Passive is simpler but wastes energy. Active is more complex but improves efficiency. Active balancing is recommended for large battery packs where efficiency matters.

Use passive for small packs, active for large packs where efficiency is important.

How many cells can be monitored per BMS module?

The AC7840-SENSOR can monitor up to 16 cells per module. For larger packs, multiple modules are used in a distributed architecture. Each module has its own MCU and communication interface. This modular approach enables scalability from small to very large battery packs.

Design modular system with 12-16 cells per module for flexibility.

What communication interfaces are supported?

The BMS solution supports CAN-FD for high-speed vehicle communication and isolated SPI for inter-module communication. CAN-FD provides 2-5 Mbps data rate for fast status updates. Isolated SPI enables reliable communication between modules at high voltage differentials.

Use CAN-FD for vehicle interface, isolated SPI for module-to-module communication.

What safety features are included in the BMS?

The BMS includes comprehensive safety features: over-voltage protection, under-voltage protection, over-current protection, over-temperature protection, and short-circuit protection. ASIL-D MCU provides redundant monitoring. Fault detection triggers safe state within milliseconds.

Comprehensive safety features ensure protection against all battery hazards.