Battery Branch SOC Control During Abnormal Communication
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Solution Overview
Problem
Current battery systems face challenges in determining the state of charge (SOC) accurately during abnormal communication in battery branches, leading to potential over-discharge or under-discharge, which affects the endurance mileage and service life of batteries.
Innovation Solution
A control method and apparatus that determine the number of closed battery branches in a battery system with abnormal communication and calculate the SOC based on this number, using insulation resistance values and communication states to ensure accurate SOC estimation and prevent battery damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the battery system uses parallel connection of multiple battery branches to meet capacity requirements, then the battery capacity and performance are improved, but the complexity of determining SOC during abnormal communication increases
Solution Approach 1:
The battery system is divided into multiple independent battery branches, each with its own communication capability. The control device can identify the communication state of each branch individually and determine the number of closed branches M, allowing segmented analysis of each branch's contribution to the total SOC.
Solution Approach 2:
The control device acts as an intermediary that receives communication from battery management units of each branch, determines communication states, and calculates the overall SOC based on the number of closed branches M and individual branch SOC values, mediating between individual branch data and system-level SOC determination.
2Measurement precision
If the system determines SOC based on all battery branches, then the SOC accuracy is improved, but the reliability decreases during abnormal communication conditions
Solution Approach 1:
The system dynamically adjusts the SOC determination method based on the communication state. When communication is normal, it uses SOC values from all N branches; when abnormal communication occurs, it dynamically identifies the number of closed branches M and uses only those branches for SOC calculation, ensuring reliability under varying conditions.
Solution Approach 2:
The control device receives feedback from battery management units about communication states and SOC values. Based on this feedback, it determines whether communication is abnormal, identifies the number of closed branches M, and adjusts the SOC calculation accordingly, creating a closed-loop feedback mechanism for reliable SOC determination.
3Productivity
If the system continues to use all battery branches for SOC calculation during abnormal communication, then the calculation simplicity is maintained, but the battery safety deteriorates due to potential over-discharge
Solution Approach 1:
The system performs preliminary identification of the number of closed branches M before SOC calculation. By detecting communication states in advance and determining which branches are actually closed and contributing to the output, it prevents the harmful effect of including disconnected branches in SOC calculation, thereby avoiding over-discharge before it occurs.
Solution Approach 2:
The abnormal communication condition, which would normally be a harmful factor leading to incorrect SOC calculation, is converted into a beneficial opportunity. The system uses the communication state information to identify the exact number of closed branches M, transforming the potential error source into accurate SOC determination by calculating based on M rather than assuming all N branches are active.
Data Source
AI summary
Embodiments of this application provide a control method and control apparatus for a battery system. The battery system includes N battery branches connected in parallel, N being a positive integer greater than 1. The control method includes: in a case of abnormal communication in at least one of the N battery branches, determining a number M of closed battery branches in the battery system, M being an integer less than or equal to N; and determining a state of charge SOC of the battery system based on the number M of closed battery branches. The control method and control apparatus in the embodiments of this application are conducive to improving the performance of the battery system.