Deformable Current Collector Venting for Battery Safety
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Prismatic secondary batteries used in hybrid vehicles face safety issues due to uneven heat dissipation, which can lead to unsafe conditions during overcharging, as the increased size of the battery affects heat dissipation between its inner and outer portions.
Innovation Solution
The design incorporates a rolled laminate electrode assembly with non-coating portions at ends, paired current collectors with deformable end portions that extend along the battery case, and a cap plate with a vent, allowing for electrical shorting between electrodes when the battery is overcharged, preventing further charging and ensuring safety through controlled gas release and heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the battery size is increased to provide high capacity for vehicle use, then the energy storage capacity is improved, but the heat dissipation performance deteriorates due to uneven heat dissipation between inner and outer portions
Solution Approach 1:
The harmful effect of heat accumulation is extracted and released through the vent mechanism. When overheating occurs, the vent opens to release gas and reduce internal pressure, preventing thermal runaway while maintaining the high-capacity prismatic battery design.
Solution Approach 2:
The deformable portions of the current collectors are pre-configured to bend and contact the cap plate at specific positions. This preliminary arrangement ensures that when heat accumulation reaches a critical level, the short circuit is automatically triggered to prevent further heating, countering the thermal runaway before it can propagate.
2Quantity of substance
If the battery size is increased to provide high capacity, then the energy storage capacity is improved, but the safety deteriorates due to unsafe conditions during overcharging
Solution Approach 1:
The battery incorporates a self-protecting mechanism where the deformable current collector portions automatically trigger a short circuit when overcharging or overheating occurs. This self-service safety feature eliminates the need for external protection circuits while maintaining high capacity, as the battery protects itself through the mechanical deformation and contact with the cap plate.
Solution Approach 2:
The harmful effects of overcharging and heat accumulation are converted into a beneficial safety mechanism. The thermal expansion and gas pressure generated during overcharging cause the deformable portions to bend and create a controlled short circuit, transforming the harmful thermal runaway into a protective shutdown mechanism.
3Reliability
If deformable portions are added to current collectors to enable safety short circuits, then the safety is improved, but the device complexity increases
Solution Approach 1:
The current collector serves multiple functions: its primary function of collecting and transporting current, and a secondary safety function through its deformable portions that automatically trigger short circuits during overcharging. This multi-functionality adds safety without requiring separate protection devices, as the current collector itself becomes the safety mechanism through its ability to deform and contact the cap plate.
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 configuration effectively prevents further charging by inducing short circuits between the positive and negative electrodes when the battery is overcharged, enhancing safety by allowing controlled heat and gas release, thus addressing the safety concerns related to uneven heat dissipation.
Implementation Method 1
each current collector including a current collector plate having an end portion, each end portion extending along the lengthwise direction of the case such that the end portions of the current collector plates of the pair of current collectors are spaced apart from each other
Data Source
AI summary
A secondary battery including a case having a lengthwise direction and including a space therein, an electrode assembly disposed in the space in the case, the electrode assembly including a rolled laminate of a positive electrode plate, a negative electrode plate and a separator interposed therebetween and having non-coating portions at ends thereof, a pair of current collectors, each current collector being electrically connected to one of the non-coating portions of the electrode assembly, each current collector including a current collector plate having an end portion, each end portion extending along the lengthwise direction of the case such that the end portions of the current collector plates of the pair of current collectors are spaced apart from each other in a central region in the lengthwise direction of the case, and a cap plate coupled to a top of the case to seal the case, the cap plate having a vent disposed therein at a position corresponding to the end portions of the current collector plates.