Battery Cell Balancing Using SOH-Aware Target Selection
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Solution Overview
Problem
Existing battery management systems indiscriminately balance battery cells regardless of their aging degree, leading to inefficient and potentially harmful balancing that accelerates battery degradation.
Innovation Solution
A battery management apparatus and method that determines whether to perform balancing based on the aging state of each battery cell, using a state of health (SOH) calculation to select balancing targets and perform balancing only when necessary, minimizing aging and preventing overcharging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If indiscriminate balancing is performed on all battery cells regardless of aging degree, then balancing operation is simplified and can be performed continuously, but battery life degrades due to continuous discharging through balancing
Solution Approach 1:
The patent applies local quality by differentiating balancing operations based on the aging degree (SOH) of individual battery cells. Instead of uniform balancing for all cells, the system selectively performs balancing only on cells with SOH greater than or equal to a reference value, tailoring the balancing approach to the specific condition of each cell to prevent unnecessary degradation.
Solution Approach 2:
The patent utilizes parameter changes by introducing SOH (state of health) as a critical parameter for determining balancing eligibility. The system dynamically adjusts balancing operations based on the SOH parameter, comparing it against a reference value to decide whether to perform balancing, thereby optimizing both operation efficiency and battery longevity.
2Device complexity
If balancing is performed based only on SOC difference without considering SOH, then balancing target selection is simplified, but balancing efficiency decreases due to ineffective balancing operations
Solution Approach 1:
The patent applies local quality by customizing balancing operations according to the local condition (SOH) of each battery cell. Cells with different aging degrees receive different treatments: cells with SOH >= reference value undergo balancing when SOC difference exceeds threshold, while cells with SOH < reference value are excluded from balancing. This localized approach enhances balancing efficiency by avoiding ineffective operations on aged cells.
Solution Approach 2:
The patent introduces SOH as an additional parameter alongside SOC for determining balancing targets. This parameter change transforms the balancing selection criterion from a simple SOC-based approach to a composite SOC-SOH evaluation, improving balancing efficiency by ensuring that only cells capable of benefiting from balancing are selected.
Data Source
AI summary
A battery management apparatus according to an embodiment of the present invention includes a state of health (SOH) calculating unit calculating an SOH of each of a plurality of battery cells and a balancing target determining unit selecting, as a second battery cell, a battery cell having a state of charge (SOC) difference from a first battery cell having a lowest SOC among the plurality of battery cells, the SOC difference being greater than or equal to a reference value, and determining a balancing target by comparing an SOH of the first battery cell with an SOH of the second battery cell.