Battery Pack SOH Estimation Using Stress-Parameter Feedback
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Solution Overview
Problem
Battery packs experience capacity degradation due to solid-electrolyte interphase (SEI) thickening and mechanical stresses, leading to performance deterioration and limited cycle life, necessitating an accurate estimation of State of Health (SOH) for timely replacement and prevention of over-charging/over-discharging.
Innovation Solution
A system and method that receive operational parameters from battery cells, determine initial and discharge-based SOH, select stress parameters for State of Charge (SOC) ranges, and transmit an ideal SOH signal when a deviation threshold is exceeded, utilizing a processor and transceiver to dynamically assess and report battery health.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple charging/discharging processes are performed by the battery pack, then the battery capacity is utilized and energy is delivered, but the SEI layer thickens leading to gradual capacity loss
Solution Approach 1:
The system performs preliminary estimation of State of Health (SOH) by analyzing operational parameters and stress parameters before significant capacity degradation occurs. This allows proactive identification of batteries approaching capacity loss thresholds, enabling timely replacement or maintenance actions to prevent further degradation from SEI thickening.
Solution Approach 2:
The system continuously monitors operational parameters (temperature, voltage, current) and stress parameters (cycle count, depth of discharge) to dynamically estimate SOH. This feedback mechanism tracks the relationship between charging/discharging cycles and capacity retention, allowing the system to adaptively manage battery usage patterns to minimize SEI-related degradation while maintaining productivity.
2Power
If mechanical stresses are exerted on electrodes during charging/discharging, then energy conversion is achieved, but particle fracture and electrode porosity reduction occur
Solution Approach 1:
The system estimates SOH by analyzing the relationship between mechanical stress parameters (derived from operational data) and electrode degradation indicators. By preliminarily assessing structural integrity through parameter analysis before visible performance deterioration, the system can predict when electrode strength will compromise power delivery capability.
Solution Approach 2:
The system continuously monitors operational parameters that correlate with mechanical stress on electrodes and uses this feedback to estimate SOH. The system tracks how repeated stress cycles affect capacity retention and adjusts operational recommendations to balance power delivery needs with electrode structural preservation.
3Reliability
If accurate SOH estimation is implemented, then battery replacement timing is optimized and over-charging/over-discharging is prevented, but system complexity increases
Solution Approach 1:
The battery management system performs self-diagnosis by autonomously collecting operational parameters, calculating stress parameters, and estimating SOH without external intervention. The system uses its own operational data to assess its health state, enabling reliable battery management while minimizing the need for complex external monitoring infrastructure.
Solution Approach 2:
The SOH estimation system serves multiple functions simultaneously: it monitors battery health, predicts replacement timing, prevents over-charging/over-discharging, and optimizes charging patterns. By consolidating these functions into a single integrated system that processes the same operational parameters for multiple purposes, the system achieves high reliability without proportionally increasing complexity.
Data Source
AI summary
A method and system for estimation of State of Health (SOH) of a battery pack is provided. The method includes determining a first SOH utilizing a set of operational parameters and a first set of stress parameters and a second SOH based on a determined discharge capacity. Utilizing the first and the second SOH, determine a second set of stress parameters of the battery pack. The method includes determining a third SOH of the battery pack based on at least one selected second set of stress parameters and the set of operational parameters and determining a deviation parameter based on the first and the third SOH. Thereafter, the method includes transmitting an ideal SOH signal to one of a server and a user device in response to the determined deviation parameter being greater than a pre-defined threshold.