Battery Cell Classification via Charging Voltage Differential Uniformity
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Solution Overview
Problem
Existing battery cell classification methods are inadequate as they rely on capacity or voltage, which do not directly correlate with performance, making it difficult to detect defective cells and classify cells by performance.
Innovation Solution
A battery cell classification system and method that calculates a charging voltage differential curve, extracts a uniformity factor from this curve, and uses this factor to identify defective cells and classify cells with similar performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If battery cells are classified based on capacity or voltage, then classification can be performed, but the classification does not accurately reflect performance uniformity
Solution Approach 1:
The patent changes the classification parameter from conventional capacity or voltage to a uniformity factor derived from the charging voltage differential curve. This parameter transformation enables accurate reflection of cell performance uniformity, as the uniformity factor captures subtle variations in charging characteristics that correlate with actual performance consistency.
Solution Approach 2:
The patent replaces conventional electrical parameter measurement (capacity, voltage) with a differential voltage analysis method. By calculating the first-order differential of the charging voltage curve and analyzing peak values, the system substitutes direct electrical measurements with a derived mathematical characteristic that better represents performance uniformity.
2Productivity
If defective cells are not detected before assembly, then assembly process is efficient, but module and pack performance deteriorates
Solution Approach 1:
The patent implements preliminary detection of defective cells before they are assembled into modules. By performing uniformity factor analysis on individual cells prior to assembly, the system identifies and excludes defective cells in advance, preventing performance deterioration in the final product while maintaining assembly efficiency.
Solution Approach 2:
The patent introduces an intermediary classification step between cell production and module assembly. The uniformity factor analysis acts as an intermediary screening mechanism that filters defective cells before they enter the assembly process, ensuring only qualified cells are assembled while maintaining production flow.
3Ease of manufacture
If battery cells with varying performance are assembled together, then manufacturing is simpler, but driving deviation increases
Solution Approach 1:
The patent applies local quality classification by grouping cells with similar uniformity factors together. Instead of treating all cells uniformly, the system identifies cells with comparable performance characteristics and assembles them together, ensuring each module contains cells of consistent quality while maintaining manufacturing feasibility.
Solution Approach 2:
The patent transforms the assembly approach by using uniformity factor as the grouping parameter instead of conventional capacity or voltage matching. This parameter change enables more accurate performance-based classification, reducing driving deviation within modules while keeping the manufacturing process relatively simple.
Data Source
AI summary
A battery cell classification system may include a charging voltage differential value measurement device configured to determine a charging voltage differential value of a battery cell before assembling a battery module, a uniformity factor extractor configured to extract a uniformity factor based on determining uniformity of the battery cell among determined charging voltage differential values, and a controller configured to compare a uniformity factor of the battery cell with a reference uniformity value, so as to reject the battery cell as a defective cell if it has the uniformity value smaller than the reference uniformity value, or to classify battery cell based on uniformity factor if it has the uniformity value at or above than the reference uniformity value.