Battery Busbar Fusing Structure for Faster Short-Circuit Isolation
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Solution Overview
Problem
Lithium-ion batteries face safety concerns due to long fusing times during short circuits, which can lead to arc energy accumulation and damage to the battery and its components, posing risks of fire or explosion.
Innovation Solution
The bus member is designed with a configuration of fusing portions where the minimum overcurrent cross-sectional area (Smin) to maximum overcurrent cross-sectional area (Smax) ratio ranges from 0.8 to 1, ensuring a short fusing time and preventing long-duration short circuits, along with features like unequal overcurrent cross-sectional areas and bent portions for enhanced mechanical strength and stress absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional busbar design with uniform cross-section is used, then manufacturing is simple, but fusing time is too long during short circuits causing arc energy accumulation and safety risks
Solution Approach 1:
The busbar is divided into multiple fusing portions with different cross-sectional areas (S1, S2, S3, ..., Sn) along its length. Each segment has a specifically designed cross-sectional area to control the fusing sequence and time, ensuring that segments with smaller cross-sectional areas fuse first to progressively disconnect the short circuit current path.
Solution Approach 2:
Different portions of the busbar have different cross-sectional areas tailored to their specific functional requirements. The fusing portions have reduced cross-sectional areas compared to the connection portions, and each fusing portion's cross-section is locally optimized to achieve the desired fusing time and sequence for safety protection.
2Reliability
If multiple fusing portions with different cross-sectional areas are used, then fusing time is reduced and safety is improved, but manufacturing precision requirements increase
Solution Approach 1:
The cross-sectional area parameter of the busbar is deliberately varied along its length to create distinct fusing portions. By changing the cross-sectional area from S1 to Sn in a controlled manner, the resistance and heat generation are adjusted to achieve different fusing times, allowing precise control over the protection sequence without requiring extreme manufacturing precision.
3Reliability
If fusing portions with smaller cross-sectional areas are used, then fusing speed increases and arc damage decreases, but mechanical strength is reduced
Solution Approach 1:
The busbar is segmented into connection portions with larger cross-sectional areas for mechanical strength and fusing portions with smaller cross-sectional areas for rapid fusing. This segmentation allows each portion to be optimized for its specific function while working together as an integrated system.
Solution Approach 2:
The connection portions maintain larger cross-sectional areas to provide the necessary mechanical strength and current carrying capacity, while the fusing portions have reduced cross-sectional areas specifically at locations where rapid fusing is required. This local differentiation of properties resolves the conflict between strength and fusing speed.
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 significantly reduces the duration of short circuits, minimizes arc damage, and enhances the safety performance of lithium-ion batteries by ensuring a quick disconnection and reducing the risk of thermal runaway.
Implementation Method 1
the fusing part can be molten by automatic heat generation when an extreme condition such as short circuit occurs in a battery
Data Source
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Figure 5~6
AI summary
The present application provides a bus member (30), a battery (100) and a power consumption device, and relates to the technical field of batteries. The bus member (30), includes a first connection portion (31) configured to be connected to a first electrode terminal (222) of a first battery cell (24); a second connection portion (32) configured to be connected to a second electrode terminal (223) of a second battery cell (25); and a plurality of fusing portions (33), one end of each fusing portion (33) being connected to the first connection portion (31), and the other end of each fusing portion (33) being connected to the second connection portion (32); where an overcurrent cross-sectional area corresponding to one of the plurality of fusing portions (33) with a maximum overcurrent cross-sectional area is expressed as Smax, and an overcurrent cross-sectional area corresponding to one of the plurality of fusing portions (33) with a minimum overcurrent cross-sectional area is expressed as Smin, and Smin and Smax satisfy the following relational expression: 0.3≤Smin/Smax≤1. The minimum overcurrent cross-sectional area Smin and the maximum overcurrent cross-sectional area Smax in all the fusing portions (33) satisfy 0.3≤Smin/Smax≤1, and in the case of a short circuit, the fusing portion (33) of the bus member (30) has relatively short fusing time, thus shortening duration of the short circuit and avoiding accumulation of arc energy of the fusing portions (33) during fusing due to a long-duration short circuit.