Battery Cell Compression Control for Fast-Charging Cycle Life
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Solution Overview
Problem
High charging rates in battery cells reduce the cycle life of traction battery packs in electric vehicles, and existing charging systems do not effectively mitigate this issue.
Innovation Solution
A battery charging system that varies the compression force applied to battery cells during charging events, using a control module to adjust between a first and second compression force based on charging rate conditions, employing devices like air bladders, cylinders, or shape memory alloys to optimize cell stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high charging rates are used to recharge battery cells quickly, then charging speed is improved, but cycle life of battery cells deteriorates
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the compression force parameter based on charging rate conditions. During high charging rates, increased compression force is applied to mitigate damage, while during low charging rates, reduced compression force is applied. This dynamic parameter adjustment resolves the contradiction by adapting the mechanical stress parameter to the electrical charging parameter, allowing fast charging without proportionally reducing cycle life.
2Reliability
If compression force is increased during high charging rates to protect battery cells, then cycle life is improved, but device complexity increases
Solution Approach 1:
The patent applies universality by integrating the compression device into the existing battery pack structure, where the same compression mechanism serves multiple functions: providing structural support, managing cell expansion, and protecting against damage during high-rate charging. This multi-functionality approach reduces overall device complexity while achieving the reliability improvement.
Solution Approach 2:
The control system automatically adjusts compression force based on charging rate detection without requiring external intervention or complex manual control mechanisms. The system monitors charging conditions and self-regulates the compression applied to battery cells, simplifying the overall control architecture while maintaining protective functionality.
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
The system extends the cycle life of battery cells by applying optimal compression forces during low and high charging rate conditions, reducing gas generation and swelling, thereby enhancing the durability of battery cells.
Implementation Method 1
a compression device configured to apply a compression force to the battery array during a charging event
Implementation Method 2
the compression device includes an air bladder
Implementation Method 3
the compression device includes a shape memory alloy structure
Data Source
AI summary
Battery charging systems and methods are disclosed for influencing battery cell cycle life by varying a compression force applied to the battery cells during charging events. An exemplary battery charging system may include a battery array, a compression device configured to apply a compression force to the battery array during a charging event, and a control module. The control module may be programmed to control the compression device to apply a first compression force during a low charging rate condition and to apply a second, different compression force during a high charging rate condition