Battery Management Unit Reference Current Estimation
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Solution Overview
Problem
Existing managing apparatuses for vehicular batteries face challenges in accurately estimating current flow during the parked mode due to measurement errors caused by noise and the wide current measurement range, which can lead to increased power consumption and reduced precision when trying to minimize power usage.
Innovation Solution
A managing apparatus for an electrochemical element that includes a control unit activating at intervals to determine a reference current value based on multiple measurements and a check process to verify if subsequent current values deviate from this reference range, allowing for accurate estimation of accumulated current without continuous high-power measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current measurement is performed continuously with high frequency to improve measurement precision, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The control unit performs current measurement periodically at predetermined intervals rather than continuously. This periodic measurement approach maintains adequate monitoring capability while significantly reducing power consumption compared to continuous high-frequency measurement.
Solution Approach 2:
The control unit determines a reference current value in advance based on multiple measured current values. This preliminary determination allows subsequent measurements to be compared against the reference value, enabling early termination of measurement when the vehicle state changes, thus reducing overall power consumption.
2Adaptability or versatility
If current measurement range is extended to cover all modes (parked, starting, maximum load) with a single sensor, then measurement coverage is improved, but measurement precision for minor current deteriorates
Solution Approach 1:
The control unit checks whether the measured current value deviates from the reference current range and uses this feedback to determine whether to continue integration. This feedback mechanism allows the system to adapt to different current conditions and maintain precision by recognizing when measurements are reliable versus when they are affected by noise.
Solution Approach 2:
The system changes the integration condition parameter based on the deviation check result. When the measured current value does not deviate from the reference current range, integration continues; when it deviates, integration stops. This dynamic parameter adjustment maintains measurement precision across different operating conditions.
3Measurement precision
If control unit activates frequently to measure current for precise estimation, then current estimation precision is improved, but power consumption increases
Solution Approach 1:
The control unit activates at predetermined intervals to perform measurement and reference value determination, rather than continuously. This periodic activation reduces power consumption while maintaining adequate estimation precision through the reference value comparison mechanism.
Solution Approach 2:
The control unit performs preliminary determination of the reference current value based on multiple measurements, then uses this reference for subsequent comparisons. This preliminary action enables the system to make accurate estimations without requiring frequent activations, thus reducing power consumption.
4Measurement precision
If current integration is performed continuously to improve SOC estimation accuracy, then SOC estimation accuracy is improved, but error accumulation from noisy measurements increases
Solution Approach 1:
The control unit implements a feedback check to determine whether the measured current value deviates from the reference current range. This feedback mechanism prevents integration of noisy or unreliable measurements, thereby maintaining SOC estimation accuracy without accumulating errors from poor quality data.
Solution Approach 2:
The system performs preliminary determination of the reference current value and establishes a reference current range before integration begins. This preliminary action creates a baseline for validating subsequent measurements, ensuring that only reliable data is integrated into the SOC estimation.
Data Source
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AI summary
A battery managing unit (30) for an energy storage apparatus (10) mounted on a vehicle (1) includes: a control unit (32) activating at an interval of a predetermined time in a parked mode of the vehicle (1); and a current sensor (41) measuring current. A CPU (33) of the control unit (32) executes: a determination process of determining a reference value based on measured current values measured for a plurality of times upon the activation; a check process of checking, at the interval of the predetermined time, whether or not a measured current value measured after the determination process deviates from a reference range that is based on the reference value; and an estimation process of estimating dark current, which has flowed in the parked mode by integrating, while the discharge current does not deviate from the reference range, current based on the reference value.