Laminated Battery Cell Protective Layers Against Internal Short Circuits
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Solution Overview
Problem
Lithium-ion batteries face a high probability of failure during mechanical abuse testing due to internal short circuits, which occur when current collectors or active layers come into contact, leading to thermal runaway.
Innovation Solution
A laminated battery cell design is introduced, featuring a first protective layer and a second protective layer, each comprising a conductive particle and a binder, to prevent internal short circuits by providing physical isolation and ensuring conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional lithium-ion battery structure is used, then manufacturing simplicity is maintained, but safety performance deteriorates due to high probability of internal short circuits during mechanical abuse
Solution Approach 1:
The battery structure is segmented into multiple functional layers: electrode sheets, protective layers, and buffer layers. Each layer has specific thickness requirements (protective layer >0.5μm, buffer layer >1μm) and compositions to prevent short circuits while maintaining overall structure integrity during mechanical abuse
Solution Approach 2:
Protective layers containing conductive particles (2-40% mass content, 0.05-5μm size) with conductive coating layers (2%-40% thickness coverage) act as intermediaries between current collectors and active layers. These intermediary layers prevent direct contact between opposing electrodes during mechanical deformation, eliminating the root cause of short circuits
2Reliability
If protective layers are added to prevent short circuits, then safety performance is improved, but device complexity increases
Solution Approach 1:
The protective layers serve multiple functions simultaneously: (1) physical separation to prevent short circuits, (2) conductive particle networks to maintain electrical conductivity (resistance 10-2000 μmΩ), and (3) mechanical buffer to absorb deformation stress. This multi-functionality reduces the need for separate components
Solution Approach 2:
The protective layers are composite materials combining conductive particles (metal oxides or carbon), binders (5-20% mass content), and optional non-conductive particles. This composite structure integrates electrical conductivity, mechanical strength, and protective functions in a single layer, simplifying the overall battery design
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 laminated battery cell significantly improves the safety performance of lithium-ion batteries by reducing the likelihood of short circuits and maintaining good cycle performance, while also ensuring excellent safety and energy storage capabilities.
Implementation Method 1
the conductive particle is an inorganic filler with a conductive coating layer on its surface
Implementation Method 2
the first protective layer and the second protective layer each independently includes a conductive particle and a binder
Data Source
AI summary
The present application provides a laminated battery cell and a lithium-ion battery, where the laminated battery cell includes an electrode sheet assembly and a protection assembly, where the protection assembly is located on the surface of the outer electrode sheet of the electrode sheet assembly; the electrode sheet assembly includes at least one functional electrode sheet, which includes a first current collector, a first protective layer and a first active layer, the first protective layer being located between the first current collector and the first active layer; the protection assembly includes a second current collector and a second protective layer that is away from the electrode sheet assembly; the first protective layer and the second protective layer each independently include a conductive particle and a binder, preventing the lithium-ion battery from internal short circuit during mechanical abuse, and making the lithium-ion battery has excellent safety performance.