SOH-Based Current Distribution for Battery Cell Aging
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Solution Overview
Problem
Battery management systems currently manage charging and discharging based solely on state of charge (SOC), leading to uneven aging of battery cells and capacity loss in vehicle battery packs.
Innovation Solution
A controller distributes current loads proportionally to the state of health (SOH) of each battery cell, considering current consumption patterns and limiting load-bearing times to minimize capacity loss, using switches for ON/OFF and gain control to adjust current flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the battery management system performs charging control or discharging control based only on state of charge (SOC) of the battery cells, then the control is simple and fast, but some battery cells among the plurality of battery cells are aged faster than the other battery cells, resulting in loss of total capacity of the battery pack
Solution Approach 1:
The patent applies local quality by transitioning from uniform SOC-based control to individualized SOH-based control for each battery cell. The controller determines the SOH of each battery cell and distributes current loads according to each cell's specific health status, allowing different control parameters for different cells based on their individual conditions. This resolves the contradiction by maintaining simple overall control architecture while implementing differentiated local control strategies for each cell.
Solution Approach 2:
The patent implements dynamics by making the current distribution strategy adaptive and variable rather than fixed. The controller dynamically adjusts the current load allocated to each battery cell based on real-time SOH measurements and driving patterns. This dynamic adjustment allows the system to optimize battery cell health uniformity while maintaining operational simplicity through automated adaptation.
2Duration of action of stationary object
If the controller distributes current load proportionally to state of health (SOH) of each battery cell, then uneven aging of battery cells is minimized and total capacity loss is reduced, but the control complexity and calculation requirements increase
Solution Approach 1:
The patent applies preliminary action by pre-establishing the SOH-based current distribution strategy and SOH determination methods. The controller is pre-programmed with the logic to calculate SOH and distribute current loads accordingly. This preliminary preparation reduces real-time computational complexity while extending battery pack lifetime through optimized current management.
Solution Approach 2:
The patent implements self-service by enabling the battery management system to automatically determine SOH values and adjust current distribution without external intervention. The system autonomously monitors battery cell conditions, calculates appropriate current loads based on SOH, and implements the distribution strategy, reducing the need for complex external control mechanisms.
3Adaptability or versatility
If the controller considers current consumption pattern of the battery pack to determine current load magnitude, then the control adapts to driving propensity and optimizes battery performance, but the measurement and control requirements become more complex
Solution Approach 1:
The patent applies universality by designing the current consumption pattern analysis to serve multiple functions simultaneously. The same measurement data used for determining current load magnitude also provides insights into battery usage patterns, state estimation, and performance optimization. This multi-functional approach reduces the need for separate complex measurement systems while enhancing adaptability to different driving patterns.
Data Source
AI summary
A vehicle includes: a battery pack including a plurality of battery cells connected in parallel; and a controller configured to distribute a current load having a magnitude proportional to a state of health (SOH) of each of the plurality of battery cells to each of the plurality of battery cells, and to control the charging and discharging of each of the plurality of battery cells according to the magnitude of the distributed current load.