Battery Module Venting Structure for Spark and Oxygen Isolation
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Solution Overview
Problem
Battery modules in energy storage systems and electric vehicles face safety risks due to uncontrolled venting of high-temperature gas and sparks, which can lead to fires and explosions, exacerbated by external oxygen introduction and short circuits between adjacent lithium secondary batteries.
Innovation Solution
A battery module design featuring a cell stack, module housing with spark delay portions and a fire-proof sheet assembly, including a mica sheet, to rapidly discharge venting gas and prevent external oxygen ingress, thereby minimizing spark leakage and preventing short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If venting gas is rapidly discharged to reduce internal pressure, then safety is improved, but high-temperature sparks may leak outside causing fire
Solution Approach 1:
A water tray is introduced as an intermediary component between the venting path and the external environment. The water tray fills with water during normal operation and acts as a barrier that traps sparks while allowing venting gas to escape through the water surface, preventing spark leakage outside the battery module
Solution Approach 2:
The water in the water tray creates a sealed environment that isolates external oxygen from the internal battery module. When sparks are generated during venting, they are trapped in the water-filled tray where oxygen is excluded, preventing combustion even in the presence of high-temperature sparks
2Reliability
If bus bar frame is used to prevent short circuits, then electrical safety is improved, but it may be damaged by high-temperature gas and sparks allowing oxygen ingress
Solution Approach 1:
The sealing structure uses a composite design combining the bus bar frame (for electrical connection) with a separate sealing member made of heat-resistant material. This composite structure allows the sealing member to protect against thermal damage while the bus bar frame maintains electrical safety, and the sealing member prevents oxygen ingress even when the bus bar frame is thermally damaged
3Quantity of substance
If number of battery cells is increased to achieve high capacity, then energy density is improved, but fire damage increases when thermal runaway occurs
Solution Approach 1:
The battery module is segmented into isolated compartments by partition walls, with each compartment containing specific battery cells. When thermal runaway occurs in one compartment, the partition walls contain the fire and prevent it from spreading to other compartments, allowing high-capacity battery arrangements while limiting fire damage to localized areas
Solution Approach 2:
The water tray serves as a dual-function intermediary that both enables safe venting of high-capacity battery modules and prevents fire spread. By trapping sparks and excluding oxygen, it protects the entire module even when multiple cells undergo thermal runaway
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 design effectively prevents high-temperature sparks from leaking outside and reduces the risk of external oxygen introduction, ensuring safe venting and preventing fire spread within the battery module.
Implementation Method 1
the water tray, a sealing member, may be provided, the sealing member being disposed between the water tray and the inside of the module housing and configured to seal a gap between the water tray and the inside of the module housing
Data Source
AI summary
A battery module includes a cell stack in which a plurality of battery cells are vertically stacked; a module housing including a base plate supporting the cell stack and a pair of side plates covering both side portions of the cell stack; a bus bar frame assembly covering an opening portion formed on a side of the module housing in a longitudinal direction of the module housing; and a plurality of spark delay portions protruding from an inner surface of each of the pair of side plates and spaced apart from one another in a height direction of the side plate.