Laminated Solid-State Cell Electrode Layout to Cut Parasitic Capacitance

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional laminated all-solid-state secondary batteries face challenges in improving charge and discharge capacity, pulse discharge cycle characteristics, and volumetric energy density due to parasitic capacitance and poor bondability between current collector layers and outer electrodes, which are exacerbated by the exposure of electrodes on the battery's side surface.

Innovation Solution

The laminated all-solid-state secondary battery design positions the side end portions of outer positive and negative electrodes to avoid facing each other, and forms these electrodes on the inside of the laminated body to reduce parasitic capacitance, while ensuring good bondability by filling grooves with conductive material before baking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If outer electrodes are positioned to face each other on the side surface, then electrical connection is achieved, but parasitic capacitance increases and pulse discharge cycle characteristics deteriorate

Engineering Contradiction:

Improvepulse discharge cycle characteristicsVSAvoidparasitic capacitance

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies asymmetry by positioning the side end portion of the outer positive electrode and the side end portion of the outer negative electrode such that they do not face each other. This asymmetric arrangement eliminates the parasitic capacitance generated by facing electrodes while maintaining proper electrical connection through the current collector layers, thereby improving pulse discharge cycle characteristics.

Inventive Principle:

Principle #4Asymmetry

2Reliability

If current collector layers are exposed on the side surface for outer electrode connection, then electrical connection is achieved, but bondability is poor due to contraction during sintering

Engineering Contradiction:

Improvebondability between current collector layer and outer electrodeVSAvoidmanufacturing process difficulty

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by forming the outer electrodes on the current collector layers before the sintering process. The conductive material paste is applied to the exposed current collector layers, and preliminary drying is performed to remove solvent. This ensures that when sintering occurs and the current collector layers contract, the outer electrodes are already in place and will be properly bonded, eliminating the bondability issues that would occur if electrodes were formed after sintering.

Inventive Principle:

Principle #10Preliminary action

3Quantity of substance

If outer electrodes are provided on the side surface, then electrical connection is achieved, but battery volume increases and volumetric energy density decreases

Engineering Contradiction:

Improvevolumetric energy densityVSAvoidbattery volume

Core Design Contradiction:

Quantity of substanceVSVolume of moving object

Solution Approach 1:

The patent applies merging by integrating the outer electrodes directly with the current collector layers through a bonding process. The outer positive electrode is bonded to the positive electrode current collector layer, and the outer negative electrode is bonded to the negative electrode current collector layer. This merging eliminates the need for separate external connection structures, reducing overall battery volume while maintaining electrical connection functionality, thereby improving volumetric energy density.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS12537228B2Laminated all-solid secondary cell and method for manufacturing same

Publication Date: 2026.01.27 TDK CORP

AI summary

A laminated all-solid-state secondary battery including: a laminated body in which a positive electrode and a negative electrode are laminated with a solid electrolyte layer interposed therebetween and which includes a side surface including a first side surface exposing the positive electrode current collector layer and a second side surface exposing the negative electrode current collector layer; an outer positive electrode attached to the first side surface; and an outer negative electrode attached to the second side surface, wherein the outer positive electrode is electrically connected to the positive electrode current collector layer, a side end portion of the outer positive electrode is located at a position not facing the negative electrode, the outer negative electrode is electrically connected to the negative electrode current collector layer, and a side end portion of the outer negative electrode is located at a position not facing the positive electrode.