Low-Voltage Controller Offloads BMS From High-Voltage Battery Pack
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Solution Overview
Problem
Existing battery control architectures in electric powertrains face challenges in packaging flexibility and reusability due to the integration of Battery Management System (BMS) functionality within the high-voltage rechargeable energy storage system (RESS), which limits space and increases complexity.
Innovation Solution
Offloading BMS functionality to a low-voltage controller connected via hardwired or wireless links, allowing for voltage isolation and enabling the LV controller to perform designated BMS functions, such as monitoring and control, thereby freeing up packaging space within the RESS and improving flexibility and commonality across platforms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If BMS functionality is integrated within the RESS at high-voltage levels, then battery management control is achieved, but packaging space is consumed and design flexibility is reduced
Solution Approach 1:
The patent divides the BMS functionality into separate modules: high-voltage sensing components remain within the RESS while low-voltage control functions are relocated to an external controller. This segmentation allows the RESS to retain only essential monitoring capabilities while offloading complex control operations, thereby reducing the volume occupied by BMS components within the battery system.
Solution Approach 2:
The patent extracts low-voltage control functions from the high-voltage RESS environment and places them in a separate low-voltage controller. This extraction removes unnecessary components from the RESS packaging space while maintaining full BMS functionality through the external controller that communicates with the RESS via standardized interfaces.
2Ease of operation
If BMS functionality is integrated within the RESS, then direct control is achieved, but device complexity and difficulty of repair increase
Solution Approach 1:
The patent introduces a low-voltage controller as an intermediary between the high-voltage RESS and the battery management functions. This intermediary handles complex control algorithms and decision-making, while the RESS itself remains a simpler power storage device. The intermediary communicates through standardized protocols, maintaining direct control capability while reducing overall system complexity.
3Adaptability or versatility
If BMS functionality is integrated within the RESS, then system functionality is complete, but adaptability across different platforms is reduced
Solution Approach 1:
The patent designs the low-voltage controller as a universal platform that can serve multiple battery chemistries, configurations, and vehicle applications. By separating control functions from the RESS-specific hardware, the same low-voltage controller can be adapted to different platforms through software configuration rather than hardware redesign, enhancing platform commonality while maintaining full battery management functionality through standardized communication protocols.
Data Source
AI summary
A high-voltage electrical system includes a high-voltage electrical bus, a low-voltage controller performing battery management system (BMS) functions, and a rechargeable energy storage system (RESS) connected to the HV electrical bus. The RESS has contactors connected to the voltage rails, a battery pack, a current sensor outputting a voltage signal indicative of pack current, cell monitoring units (CMUs) connected to designated battery cells that measure corresponding cell voltages, and voltage isolation hardware between the CMUs and the LV controller. The voltage isolation hardware includes the contactors and may include a transformer. The RESS and LV controller are connected via LV serial connections such that the LV controller performs the designated BMS functions, including monitoring the pack current and controlling an open/closed state of the contactors. A powertrain system includes the electrical system, an electric machine, and a coupled load.