Battery Unit Consistency Screening via Differential Voltage Analysis
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Solution Overview
Problem
Existing battery grouping methods fail to maintain consistency among single batteries after storage and shelving, leading to performance degradation due to electrochemical changes during storage.
Innovation Solution
A battery device comprising at least two battery units with characteristic values differing by no more than 0.5% to 40%, determined through discharge differential voltage analysis (DVA) curves under specific discharge rates, ensuring consistent grouping and performance post-storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If single batteries are screened based on voltage, internal resistance, and capacity indicators, then initial consistency between single batteries is improved, but consistency deteriorates after storage and shelving due to electrochemical changes
Solution Approach 1:
The patent applies preliminary action by performing accelerated aging tests on single batteries before grouping. This preliminary treatment simulates the electrochemical changes that will occur during actual storage, allowing the selection of batteries that maintain consistency after aging. The method proactively addresses the consistency deterioration problem by pre-exposing batteries to conditions that mimic long-term storage effects.
Solution Approach 2:
The patent changes the selection parameter from traditional indicators (voltage, internal resistance, capacity) to a new parameter based on differential voltage analysis characteristics after accelerated aging. This parameter change reflects the battery's electrochemical stability after undergoing aging processes, thereby selecting batteries that are more likely to maintain consistency during actual storage and use.
2Productivity
If traditional screening methods are used, then screening process is simple and fast, but the battery groups show poor consistency after storage
Solution Approach 1:
The patent introduces accelerated aging as a preliminary step before final screening. Although this adds a step to the process, it enables the use of differential voltage analysis on aged batteries, which provides a more reliable basis for selecting batteries that will maintain consistency. The preliminary aging process ensures that the subsequent screening is based on stable, post-aging characteristics rather than pre-aging states.
Solution Approach 2:
The patent replaces traditional mechanical/electrical measurement methods (voltage, resistance, capacity tests) with an electrochemical analysis method based on differential voltage curves. This substitution provides deeper insight into the battery's electrochemical stability and aging behavior, enabling more reliable consistency assessment while maintaining reasonable screening efficiency through automated curve analysis.
Data Source
AI summary
The disclosure provides a battery device, a detection method thereof, and a screening method and device of a battery unit. A difference between characteristic values of any two battery units within a preset range is controlled. The characteristic value reflects the difference between polarization internal resistances of different battery units, thereby reflecting the consistency difference between different battery units. The solution can dynamically monitor the consistency of each battery unit in the battery device, which can reflect the consistency of the battery unit during the usage process to implement the online monitoring of the battery unit, thereby providing guidance for the subsequent use of the battery device.