Used Battery Selection via Temperature-Dependent Internal Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for reusing secondary batteries in electric and hybrid cars fail to effectively exclude electrode-deteriorated batteries, which can cause voltage abnormalities due to increased internal resistance, leading to premature battery life and detection issues by control devices.
Innovation Solution
A method involving internal resistance measurement and correlation chart analysis to set a threshold for selecting batteries with specific internal resistances, ensuring that electrode-deteriorated batteries are excluded by measuring minimum voltages at specific temperatures and using regression lines to determine a lower limit for battery selection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If used secondary batteries with largely different internal resistances are combined to build a battery pack, then the quantity of reusable batteries increases, but the battery voltage difference temporarily exceeds the allowable limit during charge and discharge in low temperature environments
Solution Approach 1:
The patent applies parameter changes by measuring internal resistance at multiple temperature points (room temperature and low temperature) and using these temperature-dependent parameters to classify batteries. By establishing selection criteria based on internal resistance values at different temperatures, the method enables effective grouping of batteries with similar characteristics, thereby preventing excessive voltage differences while maximizing the quantity of reusable batteries that can be effectively utilized.
2Ease of manufacture
If used secondary batteries are selected based on internal resistance measurement at normal temperature only, then the selection process is simple, but electrode-deteriorated batteries cannot be excluded
Solution Approach 1:
The patent applies preliminary action by performing internal resistance measurements at both room temperature and low temperature before battery selection. By conducting these preliminary characterization tests and establishing selection criteria in advance, the method enables effective exclusion of electrode-deteriorated batteries. The low temperature measurement serves as a preliminary screening step that reveals electrode deterioration characteristics that would be invisible at normal temperature, thereby ensuring reliable battery performance while maintaining a systematic selection process.
3Reliability
If a control device monitors voltage difference to detect abnormalities, then battery safety is improved, but electrode-deteriorated batteries cause false voltage abnormality detections
Solution Approach 1:
The patent applies preliminary action by measuring internal resistance at low temperature and calculating expected voltage differences before assembling battery packs. By performing this preliminary characterization and using it to set appropriate monitoring thresholds, the method enables the control device to distinguish between normal voltage variations and actual abnormalities. This preliminary screening prevents false detections caused by electrode-deteriorated batteries while maintaining effective safety monitoring through properly calibrated detection parameters.
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
This approach prevents voltage abnormalities by ensuring that only non-electrode-deteriorated batteries are selected and assembled into battery packs, maintaining stable voltage differences and extending battery life.
Implementation Method 1
internal resistance measurement step of measuring a specific internal resistance at a specific battery temperature of each of the used secondary batteries
Implementation Method 2
continuously discharging each of the sample secondary batteries at a battery temperature equivalent to the specific battery temperature, and measuring a minimum voltage in the each sample secondary battery during a period of the discharge
Data Source
AI summary
A method of selecting a used secondary battery includes an internal resistance measurement step of measuring a specific internal resistance (second internal resistance) at a specific battery temperature (second battery temperature) of each of used secondary batteries, and a selection step of selecting a used secondary battery or batteries having the specific internal resistance (second internal resistance) smaller than a preset threshold from the plurality of used secondary batteries whose specific internal resistances (second internal resistance) have been measured in order to exclude an electrode-deteriorated battery from the used secondary batteries.