NiMH Battery Pack Pressure Modeling for Condition Status Detection
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Solution Overview
Problem
Current NiMH battery monitoring methods lack a comprehensive model valid for all states of charge, making it difficult to accurately assess battery conditions, especially during charging from non-zero states of charge, and fail to provide a valid status signal for battery health.
Innovation Solution
A method using a monitoring unit with a physical battery model that estimates internal pressure based on measurements of internal pressure, voltage, current, and surface temperature, generating a status signal through differential pressure analysis to indicate battery condition, allowing for detection of gas leakage, aging, and critical errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional monitoring methods using temperature, voltage and current measurements are used, then the monitoring system is simple, but the measurement precision and reliability of battery condition assessment is insufficient
Solution Approach 1:
The patent introduces internal pressure as a new monitoring parameter alongside traditional voltage, current, and temperature measurements. By measuring internal pressure and comparing it with estimated pressure from the physical model, the system achieves more accurate battery condition assessment. This parameter addition directly addresses the measurement precision issue while maintaining manageable system complexity through efficient integration into the existing monitoring framework.
Solution Approach 2:
The patent employs a physical battery model as an intermediary component that estimates internal pressure based on measured parameters (voltage, current, temperature). This estimated pressure serves as a reference value against which the actual measured internal pressure is compared. The intermediary model enables accurate battery condition assessment without requiring direct complex measurements of all internal states, thus improving measurement precision while keeping the system complexity manageable.
2Reliability
If a comprehensive physical battery model valid for all states of charge is implemented, then the reliability of monitoring is improved, but the device complexity increases
Solution Approach 1:
The patent develops a physical battery model that is universally applicable across all states of charge, from 0% to 100%. This single model structure handles multiple functions: estimating internal pressure during charging, discharging, and resting states; validating battery condition across the entire operating range; and providing consistent monitoring reliability regardless of the battery's charge state. The universal model eliminates the need for separate models for different operating conditions, improving reliability while managing complexity through a unified approach.
3Measurement precision
If internal pressure measurement and estimation are performed to generate status signals, then the measurement precision and battery condition detection capability are improved, but the device complexity increases
Solution Approach 1:
The patent implements a feedback mechanism where the physical battery model continuously estimates internal pressure based on measured voltage, current, and temperature, and this estimated pressure is fed back for comparison with the actual measured internal pressure. The differential between estimated and measured pressure generates status signals that indicate battery condition. This feedback loop improves detection accuracy by continuously validating the battery state while managing complexity through the structured feedback architecture that integrates seamlessly with existing monitoring parameters.
Data Source
AI summary
The present invention relates to a method (200) for generating a status signal (SS) indicating a battery condition status of a NiMH battery pack (101) comprising a plurality of NiMH cells (C1,C2,C3) using a monitoring unit (100). The monitoring unit (100) comprises: a measuring unit (102) operable to generate a data signal (DS) comprising information about measurements from the group of an internal pressure (Pi) of the NiMH battery pack (101): a battery voltage (Vb) of the NiMH battery pack (101); a battery current (Ib) flowing to, or from. the NiMH battery pack (101): a surface temperature (Text) of the NiMH battery pack (101). The monitoring unit further comprises a controlling unit (103) operable to receive the data signal (DS) from the measuring unit (102) and operable to generate the status signal (SS) wherein the controlling unit (103) is further operable to estimate the internal pressure of the NiMH battery pack (101) with a physical battery model (300). The method (200) comprising measuring (S1) the internal pressure; measuring (S2) the battery voltage (Vb); measuring (S3) the battery current (Ib); measuring (S4) the surface temperature (Text) of the NiMH battery pack; estimating (S5) an internal gas pressure of the NiMH battery pack (101) using the physical battery model (300) and said measurements; generating (S6) the status signal indicating a battery condition status of the NiMH battery pack (101) based on a differential pressure between the estimated internal pressure and the measured internal pressure.