Battery Current Breaking Structure via Cell Expansion
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Solution Overview
Problem
Industrial hybrid vehicles with large-capacity, high-voltage batteries connected in parallel face challenges in implementing a current breaking structure due to the need to cut all lead wires, making it difficult to prevent safety accidents from overcharge compared to passenger hybrid vehicles with series-connected batteries.
Innovation Solution
A current breaking structure where lead wires from parallel-connected battery cells are bonded to an outer busbar within a battery module, utilizing the expansion phenomenon of lithium ion batteries to break the wires when overcharged, with end plates and a specific bonding pattern to focus expanding force for effective breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If battery cells are connected in parallel to increase capacity, then battery capacity increases, but current breaking becomes difficult because all lead wires must be cut
Solution Approach 1:
The patent divides the current breaking function into two parts: (1) The outer busbar remains intact to maintain electrical connection and structural stability, and (2) Only the lead wires bonded to the outer busbar are broken by the expanding battery cell. This segmentation allows current breaking without requiring cutting of all lead wires, thus resolving the contradiction between increased capacity and simplified current breaking structure.
Solution Approach 2:
The patent positions the lead wires and outer busbar such that the expanding battery cell will naturally break the lead wires during overcharge before the expansion reaches critical levels. This preliminary arrangement ensures that current breaking occurs automatically as part of the expansion process, eliminating the need for complex additional breaking mechanisms while maintaining the parallel connection configuration for increased capacity.
2Reliability
If lead wires are bonded to outer busbar within battery module, then current breaking is achieved through expansion, but lead wire bonding complexity increases
Solution Approach 1:
The patent designs the system so that the expanding battery cell itself performs the current breaking function by breaking the lead wires during overcharge. The lead wires are positioned and bonded in a specific pattern that allows the natural expansion force to break them without requiring external intervention or complex control systems. This self-service mechanism improves reliability while keeping the manufacturing process relatively simple.
Solution Approach 2:
The patent changes the physical state and position parameters of the lead wires and outer busbar during battery expansion. By carefully designing the bonding location and orientation of lead wires to the outer busbar, the system utilizes the dimensional changes (expansion) of the battery cell to transform from a bonded state to a broken state, achieving current breaking through parameter change rather than complex bonding procedures.
3Ease of operation
If outer busbar connects battery module to outside, then electrical connection is maintained, but safety risk increases during overcharge
Solution Approach 1:
The patent extracts the current breaking function from the outer busbar itself. The outer busbar remains as the electrical connection component, while the lead wires bonded to it serve as the sacrificial element that breaks during expansion. This separation allows the outer busbar to maintain its electrical connection function while the lead wires provide the safety function by breaking to stop current flow during overcharge.
Solution Approach 2:
The patent positions the lead wires in a location where they will be broken by expansion before the expansion reaches dangerous levels that could compromise the outer busbar or cause other safety issues. This preliminary positioning acts as a safety cushion, ensuring that current breaking occurs at an early stage of overcharge, preventing more severe safety risks while maintaining normal electrical connection during 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 overcharge-related safety accidents by ensuring effective disconnection of high-voltage batteries during overcharge, maintaining structural integrity and safety in eco-friendly vehicles like electric and hybrid vehicles.
Implementation Method 1
utilizing the expansion phenomenon of lithium ion batteries to break the wires when overcharged
Data Source
AI summary
A current breaking structure of a battery system includes lead wires, which extend from a plurality of battery cells connected in parallel with each other. The lead wires are bonded to one of two faces of an outer busbar that connect a battery module to outside, in which the one of the two faces is faced to an interior of a battery module, such that upon battery cell expansion, the lead wires are entirely broken by the outer busbar. Accordingly, in case where overcharge occurs in a pouch type lithium ion battery, i.e., in a high-voltage battery having battery cells in parallel connection and then serial connection, connecting structure is broken effectively, thus preventing in advance overcharge-related safety accident.