Secondary Battery Potential Rate Control for Life Extension
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Solution Overview
Problem
Existing secondary battery technologies face challenges in accurately evaluating the positive electrode potential and extending the service life due to the deterioration of electrodes, leading to issues with setting the potential of the positive electrode below 2.7 V (Li+/Li) and utilizing the battery capacity effectively.
Innovation Solution
The secondary battery is designed with a specific relationship between the potential decrease rate of the positive electrode and the potential increase rate of the negative electrode during charging and discharging, where the positive electrode's potential decrease rate is initially greater than the negative electrode's increase rate, and this relationship is maintained until the positive electrode's rate becomes smaller, allowing for extended service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the positive electrode potential is controlled to reach below 2.7 V during discharging, then the battery capacity is fully utilized, but the positive electrode and negative electrode deteriorate at different rates causing inaccurate potential estimation and potential evaluation failure
Solution Approach 1:
The invention changes the control parameter from absolute potential value to potential change rate ratio. By monitoring the ratio between the absolute value of the positive electrode potential change rate and the negative electrode potential change rate, the system can determine battery state without requiring accurate absolute potential estimation, thus resolving the measurement precision issue while maintaining full capacity utilization
Solution Approach 2:
The invention implements a feedback mechanism where the potential change rate ratio is continuously monitored during charging and discharging. When the ratio exceeds predetermined thresholds, the charging/discharging process is adjusted or terminated, providing closed-loop control that prevents electrode deterioration while maximizing capacity utilization
2Duration of action of stationary object
If the battery is used until the positive electrode potential decreases below 2.7 V, then the service life is extended, but the negative electrode potential may increase to 2.7 V first causing near-zero voltage and battery failure
Solution Approach 1:
The invention transitions from controlling based on absolute potential thresholds to controlling based on the ratio of potential change rates. This parameter change allows the battery to operate safely beyond traditional voltage limits by using the relative deterioration rate ratio as the termination criterion, thereby extending service life while maintaining reliability
Solution Approach 2:
The invention performs preliminary assessment of electrode deterioration by monitoring potential change rates during normal operation. By detecting when the deterioration rate ratio approaches critical values before actual failure occurs, the system can proactively adjust or terminate charging/discharging to prevent battery failure, thus extending reliable service life
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 enables the secondary battery to maintain its capacity and operational effectiveness by managing the potential rates during charging and discharging, thereby extending the product service life and ensuring the battery can operate until the negative electrode's capacity decreases.
Implementation Method 1
an ion conductor that is held between the positive electrode and the negative electrode and has a function of conducting ions between the positive electrode and the negative electrode
Data Source
AI summary
A secondary battery (10) of the present invention includes at least a positive electrode (11), a negative electrode (12), a separation layer (5) that spatially separates the positive electrode (11) and the negative electrode (12), and an ion conductor that is held between the positive electrode (11) and the negative electrode (12) and has a function of conducting ions between the positive electrode (11) and the negative electrode (12). In addition, in an initial stage of using the secondary battery (10), the secondary battery has a characteristic of a potential decrease rate of the positive electrode (11) immediately before completion of full discharging being larger than a potential increase rate of the negative electrode (12) immediately before the completion of full discharging and a characteristic of a potential increase rate of the positive electrode (11) immediately before completion of full charging being larger than a potential decrease rate of the negative electrode (12) immediately before the completion of full charging, and the secondary battery (10) is continuously used until a state in which the potential decrease rate of the positive electrode (11) immediately before the completion of full discharging becomes smaller than the potential increase rate of the negative electrode (12) immediately before the completion of full discharging.