Battery Module Bus Bar Assembly with Elastic Overcharge Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Large battery packs used in electric vehicles are at risk of overcharge, which can lead to damage, improper operation, or dangerous situations like explosion or ignition, due to inadequate control and protection mechanisms, especially when control devices fail to recognize overcharge conditions.
Innovation Solution
A battery module design featuring a first and second bus bar assembly with a sub bus bar and an elastic member, where the sub bus bar is soldered to both bus bars and an elastic member provides a restoring force to separate the sub bus bar from the bus bars during overcharge, interrupting electrical connections to prevent damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If control devices are used to prevent overcharge, then battery pack operation is controlled, but control devices may fail to recognize overcharge situations due to programming errors or inadequate coping
Solution Approach 1:
A fusible member (fuse) is introduced as an intermediary passive protection mechanism between the control device and the battery cells. This fusible member provides a backup protection layer that physically interrupts current flow when overcharge occurs, independent of control device functionality. The fusible member acts as a mechanical mediator that ensures safety even when electronic control fails.
Solution Approach 2:
The fusible member is pre-configured with a melting point designed to be lower than the battery cell's damage threshold temperature. This beforehand cushioning ensures that the fuse will melt and interrupt current flow before the battery cells reach dangerous temperatures, providing advance protection against overcharge damage without requiring active detection or response from control devices.
2Reliability
If multiple protection units are added to the battery pack, then overcharge protection is improved, but device complexity and cost increase
Solution Approach 1:
The fusible member serves as a simple intermediary protection element that adds reliability without significant complexity. It is a passive component that requires no control logic, sensors, or active management, yet provides crucial backup protection alongside the control device, effectively multiplying protection layers with minimal system complexity increase.
Solution Approach 2:
The fusible member is designed as a disposable sacrificial component that melts and becomes non-functional after triggering protection. This cheap, simple component provides reliable protection without the need for complex recovery or replacement mechanisms, as it is designed to be consumed in the event of overcharge to protect the more valuable battery cells.
3Reliability
If bus bar assembly is designed with soldered connections, then electrical connection is improved, but connection reliability decreases under thermal stress during overcharge
Solution Approach 1:
The fusible member is designed with a specific melting point parameter that is lower than the battery cell damage threshold but higher than normal operating temperatures. This parameter change ensures that the fusible member remains stable during normal operation (maintaining electrical connection reliability) but will melt under overcharge thermal stress (providing thermal protection).
Solution Approach 2:
The fusible member is positioned as an intermediary element in the electrical connection path between battery cells and external circuits. It provides a controlled weak link that protects the soldered bus bar connections from thermal damage during overcharge, as the fuse will interrupt current flow before the solder joints reach their failure temperature.
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 interrupts electrical connections during overcharge, preventing damage and ensuring safety by physically cutting off charging current, even when control devices fail to operate properly, thus enhancing the safety of battery packs in electric vehicles.
Implementation Method 1
an elastic member having a portion coupled and fixed to the sub bus bar to give a restoring force for separating the sub bus bar from the first bus bar and the second bus bar
Implementation Method 2
the sub bus bar being respectively joined to the first bus bar and the second bus bar by means of soldering
Data Source
AI summary
A battery module comprising a first battery group having at least one secondary battery; a second battery group having at least one secondary battery that does not belong to the first battery group; a first bus bar to which an electrode lead of the secondary battery belonging to the first battery group is contacted and coupled; a second bus bar spaced apart from the first bus bar so that an electrode lead of the secondary battery belonging to the second battery group is contacted and coupled thereto; a sub bus bar interposed between the first bus bar and the second bus bar to electrically connect the first bus bar and the second bus bar; and an elastic member having a portion coupled and fixed to the sub bus bar to give a restoring force for separating the sub bus bar from the first bus bar and the second bus bar.