Pressure Drop Sheet Venting for Battery Module Thermal Runaway
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Solution Overview
Problem
Secondary battery modules face the risk of thermal runaway and explosion due to abnormal heat generation, which can lead to chain reactions and significant damage, as high-temperature gas generated inside the module cannot be quickly discharged, increasing internal pressure and posing a threat to the entire module.
Innovation Solution
A battery module design incorporating a pressure drop sheet with a ventilation layer made of ceramic fiber and a sacrificial layer, where the sacrificial layer is lost at a critical temperature, allowing for rapid gas permeability and discharge of high-temperature gases through venting holes, thereby preventing pressure buildup and potential explosions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a battery module contains multiple battery cells stacked together, then the energy density and output capacity are improved, but the risk of thermal runaway propagation and internal pressure buildup increases
Solution Approach 1:
The patent divides the battery module into isolated compartments using partition walls between adjacent battery cells. This segmentation prevents thermal runaway from propagating from one cell to another, addressing the reliability concern while maintaining the ability to stack multiple cells for higher capacity.
Solution Approach 2:
The patent introduces a pressure drop sheet as an intermediary component between battery cells. This sheet allows controlled pressure equalization and gas permeation, preventing dangerous pressure buildup while maintaining cell isolation, thus resolving the contradiction between cell quantity and safety.
2Strength
If the battery module uses a sealed structure to maintain structural stability, then the mechanical strength is improved, but the ability to discharge high-temperature gas and reduce internal pressure deteriorates
Solution Approach 1:
The patent employs a pressure drop sheet made of porous material that allows gas permeation. This porous structure enables the module to discharge high-temperature gas and equalize pressure while maintaining overall structural integrity, resolving the contradiction between sealed structure and pressure relief capability.
Solution Approach 2:
The patent applies different structural qualities to different parts of the module: the overall module case maintains structural stability, while specific localized areas (pressure drop sheets and partition walls) incorporate pressure relief functionality. This local differentiation allows simultaneous achievement of structural strength and pressure discharge capability.
3Reliability
If a pressure drop sheet with ceramic fiber ventilation layer is added to enable gas discharge, then the thermal safety is improved, but the device complexity increases
Solution Approach 1:
The pressure drop sheet serves multiple functions simultaneously: it acts as a thermal insulator, a pressure relief valve, and a structural separator between cells. By combining these functions into a single component, the patent improves thermal safety without proportionally increasing device complexity.
Solution Approach 2:
The patent uses a composite structure consisting of a ceramic fiber ventilation layer combined with a sacrificial layer. This composite material provides both thermal protection and controlled pressure release functionality in a single integrated component, achieving thermal safety enhancement with minimal increase in structural complexity.
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 solution effectively prevents thermal runaway propagation and module damage by quickly discharging high-temperature gases, ensuring safer operation and reducing the risk of explosions, while maintaining structural stability and energy density.
Implementation Method 1
the sacrificial layer is lost at a critical temperature, allowing for rapid gas permeability
Implementation Method 2
a ventilation layer including ceramic fiber; and a sacrificial layer on at least one surface of the ventilation layer, the pressure drop sheet exhibits gas permeability at a critical temperature
Data Source
AI summary
The present disclosure relates to a battery module including: a battery cell stack in which a plurality of battery cells are stacked; and a pressure drop sheet on one side of the battery cell stack, in which the pressure drop sheet includes: a ventilation layer including ceramic fiber; and a sacrificial layer on at least one surface of the ventilation layer, the sacrificial layer is disposed in a direction facing the battery cell stack, and the pressure drop sheet exhibits gas permeability at a critical temperature.