Cylindrical Battery Rupture Notch for Controlled Jellyroll Ejection
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Solution Overview
Problem
Large cylindrical lithium secondary batteries face increased risks of fire or explosion due to heat and gas buildup, which can lead to side ruptures and flame spread in battery packs, especially when used in vehicles.
Innovation Solution
A lithium secondary battery design featuring a rupture notch in the can that allows controlled ejection of a portion of the jellyroll electrode assembly when internal pressure exceeds a predetermined threshold, preventing side ruptures and reducing the risk of thermal runaway.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If the battery size is increased to achieve high capacity, then the volume and energy storage increase, but the heat generation increases and the cross-sectional area for heat release does not increase proportionally, leading to increased explosion risk
Solution Approach 1:
The invention divides the single large battery into multiple smaller battery cells arranged in a modular configuration. Each cell has its own can and electrode assembly, allowing heat and gas to be contained and released individually within each cell rather than affecting the entire battery system. This segmentation reduces the overall explosion risk while maintaining high capacity through parallel arrangement of multiple cells.
2Object-generated harmful factors
If vent portions are added to release internal pressure, then gas release capability improves, but side rupture of the battery can occurs leading to continuous flame spread to adjacent cells
Solution Approach 1:
The invention introduces a flame arrester as an intermediary component within the vent portion. This flame arrester allows gas to escape from the battery cell while blocking the propagation of flames to adjacent cells. The flame arrester acts as a mediator that permits beneficial gas release while preventing harmful flame spread, thus resolving the contradiction between venting capability and safety.
3Stability of the object's composition
If the crimping portion is designed to secure the cap plate air-tightly, then sealing performance improves, but the cap plate cannot be opened for safety venting when internal pressure rises
Solution Approach 1:
The invention designs the crimping portion with dynamic characteristics that allow it to maintain a secure, air-tight seal under normal operating conditions while automatically opening when internal pressure exceeds a predetermined threshold. The crimping portion transitions from a static sealed state to a dynamic open state in response to pressure changes, enabling both reliable sealing and safety venting functions.
4Productivity
If fast charging at high voltage is implemented to increase power output, then charging speed improves, but a large amount of heat is generated near electrode tabs in a short time causing fire risk
Solution Approach 1:
The invention divides the battery into multiple smaller cells, each with its own electrode assembly and venting system. This segmentation distributes the heat generation from fast charging across multiple smaller units rather than concentrating it in a single large battery. Each cell can independently manage its thermal conditions and release pressure if needed, reducing the overall fire risk while maintaining high charging speed through parallel charging of multiple cells.
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 side ruptures and minimizes flame spread by ejecting a portion of the electrode assembly, enhancing safety in high-capacity batteries and battery packs, particularly in vehicle applications.
Implementation Method 1
The rupture notice is configured to rupture and create an opening when an internal pressure of the battery reaches a rupture pressure
Implementation Method 2
the crimping portion is configured to uncrimp when the internal pressure reaches an uncrimping pressure
Data Source
AI summary
The present disclosure relates to a battery including a battery can, an electrode assembly and an electrolyte received in the battery can, and a cap plate assembly to seal the battery can, a battery pack and a vehicle including the same. The battery can has a first end and a second end opposite to each other. When the electrode assembly is ejected through the first end of the battery can by an internal pressure, a distance from the end of the electrode assembly farthest away from the battery can to the second end of the battery can is 1.25 times or more as much as a distance between the first end portion and the second end portion of the battery can; and the ejected portion of the electrode assembly has a mass that is at least 25% of the total mass of the electrode assembly before the ejection.