Dynamic Charging Control for Olivine Battery Packs
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Solution Overview
Problem
Existing battery pack charging methods, such as constant current and constant voltage charging, can lead to uneven voltage distribution and reduced battery life due to overcharging and incomplete charging of lithium ion secondary batteries with cobalt-based, manganese-based, or nickel-based compound oxide particles, resulting in inefficient use of battery capacity and shortened usable time.
Innovation Solution
A charging method that dynamically switches between constant current and constant voltage charging based on voltage variation detection in batteries with olivine crystal structure positive electrode active materials, ensuring nearly full charge while minimizing capacity variation and extending battery life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If constant current and constant voltage charging method is used, then charging speed is improved, but battery life is shortened due to overcharging and high voltage exposure
Solution Approach 1:
The patent applies dynamic charging control by switching between constant current and constant voltage modes based on real-time voltage detection. The charging current is dynamically adjusted: constant current mode is used when voltage is below threshold, and constant voltage mode is activated when voltage reaches the threshold, optimizing both charging speed and battery life
Solution Approach 2:
The patent implements feedback control by continuously monitoring battery voltage during charging. When the voltage reaches a predetermined threshold, the system automatically switches from constant current to constant voltage mode, and can terminate charging when voltage exceeds a higher threshold, preventing overcharging and extending battery life
2Reliability
If constant current charging is used to extend battery life, then battery life is improved, but charging capacity is reduced to only 80% of total capacity
Solution Approach 1:
The patent dynamically switches between constant current and constant voltage charging modes. Constant current mode enables fast charging up to 80% capacity, then transitions to constant voltage mode to safely charge the remaining 20%, achieving both fast charging and full capacity utilization without compromising battery life
Solution Approach 2:
The patent uses periodic voltage threshold detection during charging. When voltage reaches the first threshold, the system switches from constant current to constant voltage mode. When voltage exceeds the second threshold, charging is terminated. This periodic monitoring and mode switching enables complete charging while protecting battery life
3Stability of the object's composition
If voltage balance charging is performed on series-connected batteries, then voltage distribution is improved, but charging time increases due to sequential charging termination
Solution Approach 1:
The patent segments the charging process into distinct phases: constant current phase for bulk charging and constant voltage phase for top-off charging. Each battery in the series string undergoes this segmented charging process independently based on its voltage threshold detection, ensuring voltage balance without requiring sequential charging termination
Solution Approach 2:
The patent changes charging parameters (current and voltage thresholds) based on real-time battery state. By detecting voltage thresholds and adjusting charging mode accordingly, the system achieves voltage balance across series-connected batteries while minimizing total charging time through optimized parameter selection
Data Source
AI summary
A secondary battery charging method includes the step of determining whether to perform one of a first charging control method of performing constant current charging and constant voltage charging and a second charging control method of performing only the constant current charging according to information stored in a plurality of secondary batteries including a compound oxide particle with an olivine crystal structure. The first charging control method includes the steps of performing the constant current charging of the secondary batteries, performing the constant voltage charging, determining whether voltage variation amounts of the plurality of secondary batteries are a value equal to or greater than a first set value, and storing information and firstly terminating the charging. The second charging control method includes the steps of starting the constant current charging of the plurality of secondary batteries connected to each other in series, and secondly terminating the constant current charging.