Battery Pack Busbar Disconnect Structure for Thermal Runaway Isolation
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Solution Overview
Problem
Battery modules are prone to thermal runaway, which can lead to fire propagation and damage due to improper functioning of insulating components, causing overcurrent between adjacent modules.
Innovation Solution
Incorporating a busbar with disconnecting portions that face vent holes in battery modules, designed to be weaker structurally or have higher resistance, which break or deform under thermal stress to disrupt electrical connections and prevent heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If insulating members are used to maintain insulation between battery modules, then electrical isolation is improved, but reliability deteriorates when thermal runaway occurs as insulating members fail to function properly
Solution Approach 1:
The patent extracts the insulating function from the traditional insulating member and relocates it to the busbar structure itself. The busbar includes disconnecting portions that are integrally formed with the main body, creating a built-in isolation mechanism that doesn't rely on separate insulating components that can fail during thermal runaway.
Solution Approach 2:
The disconnecting portion acts as an intermediary element between the first and second battery modules. When thermal runaway occurs, this intermediary component is designed to break first, preventing direct electrical contact and fire propagation between modules, while normally maintaining electrical connectivity when not activated.
2Reliability
If a robust busbar structure is used to ensure electrical connectivity, then electrical connection reliability is improved, but the ability to prevent fire propagation deteriorates as the busbar cannot break easily
Solution Approach 1:
The busbar is designed with non-uniform structure where the disconnecting portion has different properties than the main body. The disconnecting portion has smaller cross-sectional area, lower structural rigidity, and higher resistance, making it the weak link that breaks preferentially during thermal runaway while the rest of the busbar maintains its structural integrity for normal operation.
3Object-affected harmful factors
If disconnecting portions with smaller cross-sectional area are used to enable easy breaking, then fire propagation prevention is improved, but electrical connection reliability deteriorates due to higher resistance
Solution Approach 1:
The disconnecting portion is pre-designed with specific structural characteristics (smaller cross-section, lower rigidity) that prepare it to break at a predetermined moment during thermal runaway. This preliminary design ensures that when thermal stress occurs, the breakage happens automatically at the optimal time to prevent fire propagation while minimizing resistance impact during normal operation.
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
Prevents fire propagation and ensures stability by blocking electrical connections between modules during thermal runaway, enhancing safety and reliability of the battery pack.
Implementation Method 1
a deformation portion selectively connecting at least one end of the busbar by being deformed by gas discharged from the vent hole
Implementation Method 2
the deformation portion may include bimetal
Data Source
AI summary
A battery pack includes a plurality of battery modules including a first battery module and a second battery module; and a busbar electrically connecting the first battery module and the second battery module, wherein the first battery module or the second battery module includes a vent hole in a portion corresponding to a portion of the busbar.