Multilayer Capacitor Metal Frame with Split Conductivity
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Solution Overview
Problem
Multilayer capacitors used in power driving systems of eco-friendly and electric vehicles face challenges in thermal, electrical, and mechanical reliability due to increased equivalent series resistance (ESR) and self-heating caused by metal frames, which affect durability against vibrations and deformation.
Innovation Solution
A metal frame structure is applied to the multilayer capacitor, divided into portions with different electrical conductivities, where the portion not in contact with solder has higher conductivity than the solder, reducing ESR and improving reliability by creating a gap between the capacitor and substrate, thereby reducing stress transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal frame is used to mount the multilayer capacitor spaced apart from the substrate, then durability against vibrations and deformation is improved, but equivalent series resistance (ESR) increases
Solution Approach 1:
The metal frame is divided into different portions with different materials having different electrical conductivity. The first portion (in contact with solder) uses materials like Ni, Fe, or Sn with lower conductivity, while the second portion (not in contact with solder) uses materials like Cu, Al, Ag, or Au with higher conductivity. This local differentiation allows the frame to provide mechanical support while minimizing ESR in the electrical signal path.
Solution Approach 2:
The metal frame is constructed as a composite structure combining different metals in different portions. This composite approach allows optimization of each portion for its specific function: the first portion provides solderability and mechanical bonding, while the second portion provides low-resistance electrical conduction, thus resolving the contradiction between mechanical durability and electrical performance.
2Loss of energy
If the metal frame is made entirely of high electrical conductivity material, then ESR is reduced, but manufacturing complexity and cost increase
Solution Approach 1:
Instead of making the entire frame from high-conductivity material, only the portion that matters for electrical signal transmission (the second portion not in contact with solder) is made from high-conductivity materials. The first portion in contact with solder uses materials optimized for solderability. This localized approach reduces manufacturing complexity and cost while still achieving low ESR where it matters most.
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 enhances the durability of multilayer capacitors against vibrations and deformation while significantly reducing equivalent series resistance, improving thermal, electrical, and mechanical reliability, and potentially lowering manufacturing costs by selectively increasing conductivity in non-solder contact areas.
Implementation Method 1
a metal frame connected to the external electrode and mounted on the electrode pad of the substrate... mounting the multilayer capacitor to be spaced apart from a substrate using a metal frame
Implementation Method 2
A conductive bonding layer may be disposed between the head portion of the external electrode and the connection portion of the metal frame... bonded to a metal frame of the electronic component through a solder
Implementation Method 3
the second portion may include at least one of Cu, Al, Ag or Au... electrical conductivity of the second portion is higher than electrical conductivity of the solder... reducing ESR
Data Source
AI summary
An electronic component, which is mounted on a substrate having an electrode pad disposed on an upper surface thereof and bonded to a metal frame of the electronic component through a solder, includes a capacitor body, an external electrode respectively disposed on one end of the capacitor body, and a metal frame connected to the external electrode and mounted on the electrode pad of the substrate. The metal frame is divided into first and second portions including different metals having different electrical conductivity.