High-Nickel Lithium Battery Charging to Suppress H2-H3 Phase Transition
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Solution Overview
Problem
Rechargeable lithium batteries with high nickel content face challenges in structural degradation and reduced cycle-life due to phase transitions during charging, leading to increased resistance and decreased performance.
Innovation Solution
A charging method involving constant-current charging at a high current density of 4 C to 10 C, followed by constant-voltage charging, is employed to inhibit the H2-H3 phase transition, thereby reducing structural deterioration of the positive electrode active material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If conventional charging methods are used on high nickel content batteries, then charging time is reduced, but structural degradation and cycle-life decrease
Solution Approach 1:
The charging process uses periodic action by alternating between constant-current charging phase and constant-voltage charging phase. This periodic switching allows the battery to be charged efficiently while preventing excessive voltage that would cause H2-H3 phase transition and structural degradation, thus maintaining both short charging time and good cycle-life characteristics
Solution Approach 2:
The invention applies parameter changes by dynamically adjusting charging parameters (current and voltage) based on the battery's state of charge. During constant-current charging, the current is maintained at optimal levels, and when voltage reaches a threshold, the system transitions to constant-voltage mode, adjusting the parameter setpoint to prevent phase transition while continuing to charge, thereby resolving the contradiction between speed and reliability
2Productivity
If high current density charging is applied, then charging speed increases, but phase transition and structural deterioration occur
Solution Approach 1:
The charging method employs dynamics by transitioning from a static constant-current regime to a dynamic constant-voltage regime. This dynamic adjustment allows the system to maintain high charging speed initially, then adaptively reduce voltage stress when approaching full charge, preventing H2-H3 phase transition and structural deterioration while maximizing charging productivity
Solution Approach 2:
The constant-current charging phase allows the battery to be charged rapidly through the majority of its capacity range, skipping over the problematic voltage region where phase transition occurs. The transition to constant-voltage mode then carefully completes the charging without rushing through the sensitive voltage threshold, thus achieving high productivity while protecting structural stability
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 shortens charging time and improves the cycle-life characteristics of the battery by preventing structural degradation of the positive electrode, maintaining capacity and stability.
Implementation Method 1
generate electrical energy through oxidation and reduction reactions if (e.g., when) lithium ions are intercalated and deintercalated from the positive electrode and the negative electrode
Data Source
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AI summary
The present disclosure relates to a method for charging a rechargeable lithium battery including constant-current charging the rechargeable lithium battery at a current density of 4C to 10C; and constant-voltage charging the rechargeable lithium battery, wherein the rechargeable lithium battery includes a positive electrode active material including a lithium nickel-based composite oxide having a nickel content of greater than or equal to about 80 mol% based on 100 mol% of metals excluding lithium.