Laminated Bus Bar Current Sensor for Heat and Weight Reduction
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Solution Overview
Problem
Current sensors face challenges in achieving weight reduction and cost reduction while maintaining high precision and frequency characteristics, particularly in applications like electric cars and hybrid vehicles.
Innovation Solution
The use of a bus bar formed from a laminate material composed of two different metal materials, where the first metal material has higher density and lower electrical resistivity than the second, with the magnetic detection unit facing the surface of the bus bar, allowing for heat generation suppression and weight reduction while maintaining high frequency characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bus bar made from a single superior electrical conductor is used, then electrical conductivity is improved, but weight and cost increase
Solution Approach 1:
The bus bar is constructed as a laminate composite material consisting of a first metal material (superior electrical conductor) and a second metal material (lighter, lower cost conductor). This composite structure allows the bus bar to achieve both high electrical conductivity and reduced weight by combining materials with complementary properties, directly resolving the contradiction between conductivity and weight reduction.
Solution Approach 2:
Different regions of the bus bar are made from different metal materials optimized for their specific functions. The first metal material is positioned to provide high electrical conductivity where needed, while the second metal material is used to reduce weight and cost in regions where conductivity requirements are less stringent, achieving local optimization of properties.
2Reliability
If a bus bar made from a single superior electrical conductor is used, then electrical conductivity is improved, but cost increases
Solution Approach 1:
The bus bar uses a composite laminate structure combining a first metal material (superior conductor) and a second metal material (lighter, lower cost conductor). This allows cost reduction by using the more expensive first metal material only where high conductivity is critical, while using the cheaper second metal material for the remainder of the structure, thereby reducing overall manufacturing cost while maintaining required conductivity.
3Weight of moving object
If the second metal material has a larger dimension in the lamination direction, then weight reduction is improved, but heat generation increases
Solution Approach 1:
The invention optimizes the dimensional parameters of the metal materials in the laminate structure. By carefully controlling the thickness and area ratios of the first and second metal materials, the design achieves weight reduction through the lighter second metal material while limiting heat generation by ensuring sufficient cross-sectional area of the first metal material to maintain low electrical resistivity and reduce I²R losses.
4Loss of energy
If the first metal material is used to suppress heat generation, then electrical conductivity is improved, but weight reduction is reduced
Solution Approach 1:
The laminate structure combines a first metal material (high conductivity, high density) and a second metal material (lower conductivity, low density). The first metal material is used strategically to suppress heat generation in critical regions, while the second metal material is used to reduce overall weight, achieving an optimal balance between heat suppression and weight reduction through material composition rather than relying on a single material.
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 structure achieves a balance between reducing heat generation and weight of the bus bar, improving sensing precision and frequency characteristics, and allows for multiple measurement phases with varying precision demands.
Implementation Method 1
a magnetic detection unit placed so as to face the bus bar, the magnetic detection unit sensing a magnetic field generated around the bus bar
Implementation Method 2
The first metal material has a larger density than the second metal material, and has a smaller electrical resistivity than the second metal material
Data Source
AI summary
A current sensor has a bus bar in which a current under measurement flows and also has a magnetic detection unit placed so as to face the bus bar, the magnetic detection unit sensing a magnetic field generated around the bus bar. The bus bar is formed from a laminate material in which a first metal material and a second metal material, which are different types of metal materials, are laminated. The first metal material has a larger density than the second metal material, and also has a smaller electrical resistivity than the second metal material. The magnetic detection unit is placed so as to face a surface of the bus bar, the surface being formed from the first metal material.