Li-Ion Battery Charging Control for Side Reaction Suppression
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Solution Overview
Problem
Current charging methods for lithium-ion batteries fail to simultaneously reduce charging time and suppress degradation, as they do not accurately estimate and control side reactions, leading to increased heat generation and reduced battery lifespan.
Innovation Solution
A charging apparatus and method that utilizes a voltage and temperature measurement system coupled with an electrochemical reduced order model to determine the side reaction rate and adjust the charging current, ensuring the charging current control conditions are met to limit side reactions and optimize charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If high power chargers (DC fast charging, super charger, extreme fast charging) are used to reduce charging time, then charging time is reduced, but degradation rate increases and heat generation increases
Solution Approach 1:
The charging current is dynamically adjusted based on real-time monitoring of voltage, temperature, and calculated side reaction rates. The control unit continuously modifies the charging current magnitude to maintain optimal charging conditions, transitioning from static high-power charging to adaptive dynamic charging that responds to battery state changes.
Solution Approach 2:
The system implements feedback control by measuring voltage and temperature, calculating side reaction rates using electrochemical models, and using this information to adjust charging current. The control unit continuously monitors battery parameters and modifies charging current accordingly to prevent excessive degradation while maintaining fast charging capability.
2Loss of time
If constant current charging is used to reduce charging time, then charging time is reduced, but overcharging occurs and temperature rise increases
Solution Approach 1:
The control unit continuously monitors battery voltage and temperature, and adjusts charging current based on real-time measurements. When voltage approaches cutoff voltage or temperature rises, the charging current is automatically reduced to prevent overcharging and excessive temperature increase.
Solution Approach 2:
The system changes charging parameters dynamically by adjusting current magnitude based on battery state. Instead of maintaining constant high current, the system modifies current levels according to voltage, temperature, and side reaction rate conditions to optimize charging while preventing thermal runaway.
3Reliability
If combination of CC with CV or CP with CV charging is used to prevent overcharging, then overcharging is prevented, but charging current at low SOC is high causing temperature rise
Solution Approach 1:
The control unit continuously monitors battery parameters and adjusts charging current based on real-time feedback. This replaces the fixed CC/CV switching strategy with adaptive control that responds to actual battery conditions, preventing high current conditions that cause temperature rise while maintaining overcharging prevention.
Solution Approach 2:
The system transitions from static charging protocols with fixed current/voltage switching points to dynamic charging control where current and voltage are continuously adjusted based on real-time battery state. This dynamic adjustment prevents the high current conditions at low SOC that occur in conventional CC/CV charging.
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 reduces charging time by approximately half while minimizing capacity and power fade, making it the most effective method in balancing charging speed and degradation prevention among tested protocols.
Implementation Method 1
determining an internal state of the secondary battery, which includes an average ion concentration of anode particles, a surface ion concentration of the anode particles, an anode particle potential and an anode electrolyte potential, using a predefined electrochemical reduced order model (ROM)
Data Source
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AI summary
Disclosed is a charging apparatus and method of a secondary battery. The charging apparatus includes a control unit configured to determine an average ion concentration, a surface ion concentration and a solid phase potential for anode particles and an electrolyte potential in an anode, using a predefined electrochemical reduced order model. The control unit is further configured to determne a side rasction rate from the solid phose potential and the electrolyte potential. The control unit is futher configured to reduce the magnitude of the charging current applied to the secondary battery based on at least one selected from the limitations of a cutoff voltage, the surface ion concentration and the side reaction rate.