Pulse Charging Control for Low-Temperature Battery Protection
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Solution Overview
Problem
Lithium ion batteries face increased burden during rapid charging, particularly at low temperatures due to sudden voltage increases, heterogeneous reactions, and reduced lithium ion diffusion speeds, leading to uneven concentration distribution and battery deterioration.
Innovation Solution
A power supplying device that controls the charging process by extending the unit on time and unit off time during pulse charging as the battery temperature decreases, optimizing lithium ion diffusion and reducing the burden on the battery by adjusting the pulse pattern based on temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pulse charging is performed with high current to increase charging speed, then productivity is improved, but the burden on the battery increases due to sudden voltage increases and heterogeneous reactions
Solution Approach 1:
The patent applies periodic pulse charging action by alternating between charging periods (where current flows to the battery) and rest periods (where current is interrupted). This periodic action allows lithium ions to diffuse uniformly during rest periods, preventing heterogeneous reactions and concentration polarization while maintaining high average charging current for improved productivity.
Solution Approach 2:
The patent implements preliminary action by extending the rest period duration at lower temperatures to allow sufficient time for lithium ion diffusion before the next charging pulse. This preliminary diffusion action prevents concentration polarization and heterogeneous reactions from occurring during subsequent charging pulses, thereby reducing battery burden while maintaining charging efficiency.
2Reliability
If the diffusion speed of lithium ions decreases at low temperature, then the battery can be protected from damage, but the charging time increases and productivity decreases
Solution Approach 1:
The patent applies dynamics by dynamically adjusting the pulse charging parameters (on-time and off-time durations) based on the detected battery temperature. At lower temperatures, the rest period is extended to allow sufficient lithium ion diffusion, while at higher temperatures, the rest period is shortened. This dynamic adaptation maintains battery protection while minimizing charging time across different temperature conditions.
Solution Approach 2:
The patent implements parameter changes by modifying the pulse charging waveform parameters (current magnitude, pulse width, and rest period) according to battery temperature. Specifically, the rest period is extended at low temperatures to compensate for reduced lithium ion diffusion speed, ensuring uniform concentration distribution without excessively prolonging total charging time.
3Stability of the object's composition
If the unit on time and unit off time are extended at low temperature to promote lithium ion diffusion, then homogeneous reactions are achieved, but the total charging period increases
Solution Approach 1:
The patent applies dynamics by making the pulse charging parameters adaptive to temperature conditions. The control unit extends the unit off time specifically when battery temperature is low to ensure homogeneous lithium ion distribution, and reduces the off time when temperature is high. This dynamic adjustment achieves concentration uniformity while minimizing unnecessary time loss during 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 the burden on lithium ion batteries during pulse charging, suppressing heterogeneous reactions and side reactions, and promoting homogeneous reactions, thereby extending the battery's life and maintaining capacity.
Implementation Method 1
The diffusion speed of lithium ions decreases as the temperature decreases. When the temperature is low, the number of lithium ions that cannot return to the normal position during the off period of pulse charging increases, and unevenness in the concentration distribution of the lithium ions increases.
Data Source
AI summary
In this power supplying device used in this power storage system, a power supplying unit charges a battery. A control unit controls the power supplying unit so as to charge the battery in a pulsed manner, in at least a part of a charging period of the battery. The control unit extends a unit on time and a unit off time when charging in the pulsed manner, as the temperature of the battery becomes lower.