Secondary Battery Bus Bar Segmentation Thermal Runaway
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Solution Overview
Problem
In secondary batteries with multiple cells closely arranged, if one cell deteriorates, it can lead to thermal runaway and decreased safety, increasing the risk of accidents due to sequential deterioration of neighboring cells.
Innovation Solution
The design includes a plurality of first bus bars with a predetermined gap between them, electrically connected to battery cells, and a second bus bar with a greater thickness, which is electrically connected to the first bus bars, allowing for improved current distribution and reducing thermal stress by dispersing the load across the bus bar unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple battery cells are closely arranged to increase output, then productivity and power are improved, but the risk of thermal runaway and safety deteriorates due to sequential deterioration of neighboring cells
Solution Approach 1:
The battery pack is divided into multiple independent battery cell units with physical separation. Insulating structures are introduced between adjacent battery cells to segment the thermal and electrical pathways, preventing sequential deterioration and thermal runaway propagation while maintaining high output capacity through parallel cell configuration.
Solution Approach 2:
Insulating structures serve as intermediary elements positioned between adjacent battery cells. These intermediaries provide thermal and electrical isolation, blocking the propagation of heat and electrical faults between cells, thereby enhancing safety without compromising the overall productivity and power output of the battery pack.
2Power
If bus bars are used to electrically connect multiple battery cells, then electricity transmission is improved, but concentrated heating and thermal stress increase due to load concentration
Solution Approach 1:
The bus bar system is segmented into multiple separate bus bars instead of using a single large conductor. This segmentation distributes the electrical current and associated thermal load across multiple smaller conductors, reducing concentrated heating and thermal stress at any single location while maintaining effective electricity transmission to multiple battery cells.
Solution Approach 2:
Different regions of the bus bar system are designed with locally optimized properties. The bus bars are positioned and sized to distribute current density evenly across connection points, with insulating structures strategically placed at high-heat-generation zones. This local quality optimization reduces thermal stress in critical areas while maintaining overall electrical conductivity.
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 enhances the safety and efficiency of secondary batteries by reducing the risk of thermal runaway and improving electricity transmission, thereby preventing concentrated heating and potential accidents.
Implementation Method 1
a second bus bar arranged above the plurality of first bus bars and electrically connected to the plurality of first bus bars, the second bus bar having a second thickness greater than the first thickness
Implementation Method 2
improving current distribution and reducing thermal stress by dispersing the load across the bus bar unit
Data Source
AI summary
To improve the safety of a secondary battery, the present disclosure provides a secondary battery including: a plurality of battery cells each including a case and an electrode assembly accommodated in the case; a plurality of first bus bars electrically connected to the plurality of battery cells and having a first thickness, the plurality of first bus bars being apart from each other with a predetermined gap therebetween; and a second bus bar arranged above the plurality of first bus bars and electrically connected to the plurality of first bus bars, the second bus bar having a second thickness greater than the first thickness.