Temperature-Responsive Bus Bar for Pouch Cell Overheat Current Blocking
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Solution Overview
Problem
Lithium secondary batteries used in battery modules and packs face safety risks due to potential overheating and explosion, particularly in electric vehicles, where conventional safety measures like PTC devices and fuses require additional mounting space and may not effectively block current flow during temperature rises.
Innovation Solution
A battery module design incorporating a bus bar with a material layer that includes a gas generating material, such as melamine cyanurate, which increases resistance and blocks current flow when the temperature exceeds a certain threshold, ensuring safety without the need for additional space or changes to the existing manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional safety measures like PTC devices and fuses are used to block current flow during temperature rises, then safety is improved, but additional mounting space is required and device complexity increases
Solution Approach 1:
The patent combines the safety function with the existing bus bar structure by integrating a temperature-responsive material layer directly into the bus bar. This merging eliminates the need for separate PTC devices or fuses, thereby preventing current flow during overheating without requiring additional mounting space.
Solution Approach 2:
The bus bar is designed to perform multiple functions: it serves as both the electrical connection component and the safety device. The material layer within the bus bar provides temperature-responsive resistance change, enabling the bus bar to automatically block current flow when overheating occurs, thus eliminating the need for dedicated safety components.
2Reliability
If conventional safety measures like PTC devices and fuses are used to block current flow during temperature rises, then safety is improved, but device complexity increases
Solution Approach 1:
The safety function is merged into the existing bus bar structure through the integration of a temperature-responsive material layer. This eliminates the need for separate PTC devices or fuses, thereby reducing device complexity while maintaining safety functionality.
Solution Approach 2:
The bus bar with the temperature-responsive material layer performs safety functions autonomously based on temperature changes. When overheating occurs, the material layer automatically changes resistance to block current flow without requiring external control systems or additional safety components, thereby simplifying the overall device complexity.
3Reliability
If the bus bar uses a material layer with gas generating material to block current flow when temperature rises, then safety is improved and mounting space is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The bus bar employs a composite structure consisting of a metal layer and a material layer containing gas generating material (such as melamine cyanurate). This composite material approach enables the bus bar to exhibit temperature-responsive resistance changes while maintaining manufacturability through conventional lamination or coating processes, balancing safety enhancement with reasonable manufacturing precision requirements.
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 blocks current flow when the battery module overheats, enhancing safety by preventing charging and reducing the risk of explosion or ignition, while maintaining normal conductivity and performance, thus improving the safety of the battery module, pack, and vehicle.
Implementation Method 1
the material layer comprises a gas generating material that is decomposed at a certain temperature or higher to generate a gas and increase resistance
Implementation Method 2
a gas generating material that is decomposed at a certain temperature or higher to generate a gas and increase resistance
Data Source
Figure 1
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AI summary
Provided are a battery module with improved safety by blocking current when the temperature rises, a battery pack including the battery module, and a vehicle including the battery pack. The battery module includes two or more battery cells, wherein the two or more battery cells has a structure in which an electrode assembly having both ends respectively connected to one ends of electrode leads of opposite polarities is accommodated and sealed in a pouch case together with an electrolyte and other ends of the electrode leads are exposed to an outside of the pouch case, wherein the electrode leads and a bus bar are connected in electrically connecting a first battery cell and a second battery cell of the two or more battery cells, wherein the bus bar comprises a metal layer and a material layer that is normally conductive but may act as a resistor when a temperature rises, and wherein the material layer comprises a gas generating material that is decomposed at a certain temperature or higher to generate a gas and increase resistance.