Secondary Battery Charging Control for LiCoO2 Crystal Reversibility
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Solution Overview
Problem
Current power storage systems face challenges in achieving high energy density and safety, particularly in maintaining the reversibility of the crystal structure of positive electrode active materials during charging, which affects the battery's capacity and lifetime.
Innovation Solution
A charging method and unit that monitor and control the charge process by detecting changes in the crystal structure of the positive electrode active material, specifically using lithium cobalt oxide with magnesium, to prevent collapse and ensure substantial reversibility, even at increased charge voltages, thereby optimizing charge depth and capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If charge voltage is increased to improve energy density, then charge capacity is improved, but crystal structure collapse occurs reducing battery lifetime
Solution Approach 1:
The patent employs feedback control by continuously monitoring the charge voltage and detecting the crystal structure state of the positive electrode active material. When the crystal structure is detected to be collapsing, the charging process is automatically adjusted or stopped, creating a closed-loop control system that prevents damage while maximizing charge capacity.
Solution Approach 2:
The patent changes the operational parameters of the charging process by dynamically adjusting charge voltage based on the detected crystal structure state. Instead of using a fixed high voltage, the system modulates voltage levels in response to real-time structural feedback, enabling high capacity charging without causing collapse.
2Use of energy by moving object
If charge voltage is increased to achieve high energy density, then energy storage capacity is improved, but crystal structure reversibility deteriorates
Solution Approach 1:
The detection unit provides continuous feedback on the crystal structure reversibility state, enabling the control system to adjust charging parameters dynamically. This feedback mechanism ensures that the crystal structure maintains its reversibility even at elevated charge voltages, preserving both energy capacity and structural stability.
Solution Approach 2:
The patent transforms the static charging process into a dynamic one by continuously monitoring crystal structure reversibility and adjusting charge voltage in real-time. This dynamic approach allows the system to operate at higher energy densities while maintaining structural reversibility through adaptive control.
3Ease of operation
If conventional charging control is used to simplify the charging process, then ease of operation is improved, but ability to detect and prevent crystal structure collapse is reduced
Solution Approach 1:
The detection unit enables the battery system to self-monitor its own crystal structure state during charging. This self-service capability allows the system to automatically detect early signs of crystal structure collapse without external intervention, maintaining operational simplicity while enhancing detection capability.
Solution Approach 2:
The patent introduces a detection unit as an intermediary component that bridges the gap between simple charging operation and complex crystal structure monitoring. This intermediary device translates complex structural changes into detectable signals, enabling collapse detection without complicating the overall charging process.
Data Source
AI summary
A power storage system with a high energy density is provided. A power storage system with a high degree of safety is provided. A secondary battery with a high energy density is provided. A secondary battery with a high degree of safety is provided. A charging unit has a function of controlling start and stop of charge of a secondary battery and a function of controlling a charge current of the secondary battery. The secondary battery includes a positive electrode, the positive electrode includes a positive electrode active material particle, the positive electrode active material particle is lithium cobalt oxide to which magnesium is added. The charging unit has a function of controlling charge of the secondary battery by a first step of starting constant current charge of the secondary battery at a time t1; and a second step of stopping the charge at a time t2. A crystal structure of the lithium cobalt oxide at the time t2, which is determined by powder X-ray diffraction, is a crystal structure represented by a space group R-3m.