Ceramic Multilayer Capacitor Low ESR Electrode Design
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Solution Overview
Problem
Conventional ceramic multilayer capacitors have high equivalent series resistance (ESR) values, which limit their performance in high-power applications and require improved properties such as reduced ESR, increased breakdown field strength, and enhanced current carrying capacity.
Innovation Solution
A ceramic multilayer capacitor design featuring a cuboid base body with ceramic layers and internal electrode layers, where the electrode layers are arranged to maximize the feed cross-section area, including floating electrodes that overlap with other electrode layers, and using copper for electrodes to achieve low ESR and improved robustness, along with a specific ceramic material formula that allows for low sintering temperatures and high dielectric constants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional ceramic multilayer capacitor design is used, then manufacturing is simpler, but ESR value is high
Solution Approach 1:
The patent transitions from conventional planar electrode arrangements to a three-dimensional stacked configuration where electrode layers are arranged in multiple levels with vertical and horizontal connections. This dimensional change increases the feed cross-section area through which current flows, thereby reducing ESR while managing the increased structural complexity through systematic layering
Solution Approach 2:
The capacitor is divided into multiple electrode layers (first, second, third electrode layers) with distinct functions - some connected to external contacts and others floating. This segmentation allows current to flow through multiple parallel paths via the stacked electrode structure, effectively reducing overall ESR while maintaining manufacturability through modular layer construction
2Loss of energy
If electrode layers are arranged to maximize feed cross-section, then ESR is reduced, but manufacturing precision requirements increase
Solution Approach 1:
By stacking electrode layers in the vertical dimension rather than merely expanding in the horizontal plane, the patent achieves increased feed cross-section area without proportionally increasing lateral alignment tolerances. The vertical stacking provides an additional degree of freedom that reduces the stringency of in-plane positioning requirements
Solution Approach 2:
The electrode layers serve multiple functions simultaneously - they provide electrical conduction paths, create capacitive structures with dielectric layers, and establish mechanical stacking registration. This multi-functionality allows the same structural elements to meet both electrical performance requirements and manufacturing alignment constraints
3Loss of energy
If copper is used for electrodes, then ESR is reduced, but oxidation resistance decreases
Solution Approach 1:
The patent employs composite electrode structures where copper provides the primary low-resistance conduction path, while protective coating layers (such as nickel or other barrier metals) are applied to the copper surfaces. This composite approach maintains the low ESR benefit of copper while the protective layers prevent oxidation and enhance long-term reliability
Solution Approach 2:
Intermediary protective layers are introduced between the copper electrode material and the surrounding environment. These intermediary layers act as barriers to oxygen diffusion while maintaining electrical conductivity, thus preserving copper's low ESR properties while protecting against oxidation
4Strength
If floating electrodes are added, then breakdown field strength is increased, but device complexity increases
Solution Approach 1:
The electrode system is segmented into functional groups - electrodes connected to external contacts and floating electrodes that are not directly connected to terminals. This segmentation creates additional dielectric interfaces that distribute electric field stress, increasing breakdown field strength while the modular nature of the segmented structure keeps manufacturing complexity manageable
Solution Approach 2:
Floating electrodes are positioned in the vertical stacking dimension, creating additional insulation barriers between opposite-polarity electrodes. This vertical arrangement increases breakdown field strength without requiring complex lateral electrode patterns, as the protective effect is achieved through the stacked layer configuration
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 design achieves a significantly reduced ESR value, increased breakdown field strength, and improved current carrying capacity, enabling efficient performance in high-power applications with ESR between 3 mΩ and 5 mΩ at frequencies from 100 kHz to 1 MHz.
Implementation Method 1
the first electrode layers (41) are electrically conductively connected directly to the first external contact (51), that is to say the first electrode layers directly adjoin the first external contact and are directly connected to the first external contact
Implementation Method 2
The base body comprises dielectric layers, which are arranged to form a stack along a layer stacking direction. The dielectric layers are preferably designed as ceramic layers.
Implementation Method 3
the ratio of the feed cross section of the electrode layers to the useful cross section, ie to the area determining the capacitance, can be significantly increased by the ratios specified here between the width B and the height H of the base body
Data Source
Figure 1~2
AI summary
A ceramic multi-layer capacitor includes a main body, which has ceramic layers arranged along a layer stacking direction to form a stack, and first and second electrode layers arranged between the ceramic layers. The multi-layer capacitor also includes a first external contact-connection arranged on a first side surface of the main body and electrically conductively connected to the first electrode layers, and a second external contact-connection arranged on a second side surface (62) of the main body (2). The second side surface is situated opposite the first side surface and is electrically conductively connected to the second electrode layers.