All-Solid Battery Case Structure With Direct Collector Contact
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Solution Overview
Problem
Lithium-ion batteries used in electric vehicles face safety concerns due to their liquid electrolyte, which can ignite when exposed to water, necessitating the development of all solid secondary batteries with improved stability and safety features.
Innovation Solution
An all solid secondary battery design featuring an electrode assembly with an anode and cathode current collector portions, insulated cases, and an elastic insulator that deforms with volume changes, allowing direct contact between the current collectors and cases, eliminating the need for additional electrical connections and enhancing safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If liquid electrolyte is used in lithium-ion batteries, then high energy density is achieved, but safety deteriorates due to ignition risk when exposed to water
Solution Approach 1:
The patent changes the physical state of the electrolyte from liquid to solid, fundamentally altering the safety characteristics while maintaining energy density. The solid electrolyte eliminates the ignition risk associated with liquid electrolytes while preserving the high energy density required for automotive applications.
2Reliability
If solid electrolyte is used to improve safety, then stability is improved, but device complexity increases due to additional insulation requirements
Solution Approach 1:
The patent merges the insulation function into the case structure itself, which serves dual purposes: containing the electrode assembly and providing electrical insulation. The case is designed with insulating properties that eliminate the need for separate insulation components, thereby reducing device complexity while maintaining stability.
Solution Approach 2:
The case structure is designed to perform multiple functions simultaneously: mechanical containment, electrical insulation, and structural support. This multi-functionality reduces the overall number of components needed in the battery assembly, simplifying the device while maintaining high stability.
3Reliability
If additional electrical connections (bus bars) are used, then electrical connectivity is ensured, but device complexity and volume increase
Solution Approach 1:
The patent extracts and eliminates the bus bar component from the battery structure. Instead of using separate electrical connection elements, the design relies on direct contact between the electrode assembly and the conductive case, which serves as both the container and the electrical connection pathway, thereby reducing device complexity and volume.
Solution Approach 2:
The case structure is designed to serve multiple functions: mechanical containment, electrical insulation (where needed), and electrical conduction (where contact is required). This multi-functionality eliminates the need for dedicated bus bars, simplifying the connection structure while ensuring reliable electrical connectivity.
4Manufacturing precision
If rigid case structure is used, then manufacturing precision is improved, but adaptability deteriorates due to inability to accommodate volume changes during charging
Solution Approach 1:
The patent introduces dynamic characteristics to the case structure by incorporating elastic insulation elements that can deform in response to volume changes during charging and discharging. This allows the otherwise rigid case to adapt to the expanding and contracting electrode assembly, maintaining manufacturing precision while gaining adaptability.
Solution Approach 2:
The patent uses elastic insulation materials that possess flexible properties, allowing them to deform and accommodate volume changes of the electrode assembly during operation. These flexible insulating elements maintain their insulating function while adapting to the dynamic volume requirements of the battery during charging and discharging cycles.
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 design enhances the safety and stability of secondary batteries by preventing electrical shorts and accommodating volume changes during charging and discharging, thereby improving durability and eliminating the need for external bus bars, resulting in a compact and efficient battery module.
Implementation Method 1
The insulator may include an elastic material. The insulator may be deformed according to changes in volumes of the electrode assembly and the case.
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
An all solid secondary battery includes an electrode assembly (100), and a case (10) accommodating the electrode assembly (100), wherein the electrode assembly (100) includes a unit cell portion (110), an anode current collector portion (120), and a cathode current collector portion (130), the case (10) includes first and second cases (11, 12) insulated from each other, the anode current collector portion (120) contacts the first case (11), and the cathode current collector portion contacts the second case (12).