Pressure-Assisted Cell Screening for Abnormal Self-Discharge
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Solution Overview
Problem
Existing methods fail to detect abnormal self-discharge in electrochemical cells until they are assembled into batteries, leading to economic and environmental drawbacks due to the need to discard entire batteries or modules containing defective cells, and potential recall campaigns.
Innovation Solution
A method and apparatus that apply pressure to electrochemical cells to simulate assembly conditions, measuring voltage differences to identify cells with abnormal self-discharge before assembly, using a container that can change pressure to apply compressive force and a detection system to measure voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If cells are monitored only after assembly into batteries, then monitoring cost is reduced, but defective cells cannot be detected until after assembly causing entire batteries to be discarded
Solution Approach 1:
The patent applies preliminary action by performing self-discharge monitoring on individual cells before they are assembled into batteries. The monitoring system measures voltage changes of cells during storage and compression phases, allowing defective cells to be identified and removed prior to battery assembly, thereby preventing waste of entire batteries while maintaining a relatively simple monitoring setup.
2Reliability
If compression force is applied to cells during monitoring, then latent defects are detected, but the monitoring process becomes more complex
Solution Approach 1:
The patent applies dynamics by implementing a two-phase monitoring process: a first monitoring phase during storage without compression, and a second monitoring phase during compression with applied force. This dynamic approach allows the system to detect both obvious and latent defects at different stages, improving detection accuracy while using the existing compression infrastructure of the assembly process.
Solution Approach 2:
The patent applies periodic action by conducting voltage measurements at multiple time points: initial voltage measurement, voltage measurement after storage period, and voltage measurement after compression. This periodic monitoring approach enables detection of self-discharge phenomena at different stages without requiring continuous complex monitoring equipment.
3Loss of time
If self-discharge monitoring is performed before assembly, then defective cells are detected early, but monitoring time and resources increase
Solution Approach 1:
The patent merges the self-discharge monitoring process with the existing cell storage and compression processes. By performing voltage measurements during the natural storage period and during the compression phase that would occur anyway in battery assembly, the system detects defective cells early without adding significant time or resource requirements separate from the existing manufacturing workflow.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively detects defective cells with abnormal self-discharge before assembly, preventing waste of entire batteries or modules and reducing the need for costly recalls.
Implementation Method 1
arranging the cells inside a container, wherein a pressure inside the container is equal to a first pressure; bringing the pressure inside the container to a second pressure greater than the first pressure
Implementation Method 2
measuring a voltage of each cell to detect whether a self-discharge value of the cell is greater than a predetermined threshold
Data Source
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AI summary
A method for monitoring self-discharge phenomena of electrochemical cells, comprising the steps of: a) providing a plurality of electrochemical cells (2), wherein each cell (2) has a first dimension and a second dimension, extending respectively along a first direction and a second direction orthogonal to one another, greater than a third dimension extending along a third direction orthogonal to the first direction and the second direction, wherein each cell (2) comprises a casing (3) and a plurality of layers arranged inside the casing (3), wherein the layers comprise at least one first electrode layer, at least one second electrode layer and at least one first separator layer interposed between the first electrode layer and the second electrode layer; b) arranging the cells (2) inside a container (4), wherein the pressure inside the container (4) is equal to a first pressure; c) bringing the pressure inside the container (4) to a second pressure greater than the first pressure; d) measuring a voltage of each cell (2) of the plurality of cells (2) to detect whether a self-discharge value of said cell (2) is greater than a predetermined threshold, wherein step c) is prior to or at least partially simultaneous with step d), and step d) is prior to a step of assembling the cells (2) into one or more batteries.