Pressure-Sensitive Battery Separator for Nonblocking Lamination
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Solution Overview
Problem
In battery cell manufacturing, the dislocation of electrode plates and separators during transit leads to contact and scrap, impairing kinetic and safety performance, and current adhesive coatings with low melting points cause layers to bond prematurely, affecting high-speed lamination efficiency.
Innovation Solution
A pressure-sensitive separator with a porous substrate coated with a mixture of 40-90 wt% first organic particles, 10-20 wt% pressure-sensitive binder polymer, and optionally 0-50 wt% second organic particles, which provides bonding under 2 MPa pressure without sticking at 1 MPa, ensuring proper fitting and stability during battery cell production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive coating with low melting point is applied to separator, then bonding between electrode plate and separator is improved, but different layers of separator bond together during rewinding and storage
Solution Approach 1:
The invention changes the pressure parameter by applying different pressures at different stages: low pressure (≤1 MPa) during rewinding and storage to prevent premature bonding, and high pressure (≥2 MPa) during lamination to achieve proper bonding between electrode plate and separator. This parameter change resolves the contradiction by controlling the bonding behavior through pressure modulation.
Solution Approach 2:
The invention makes the bonding properties dynamic by using a pressure-sensitive binder polymer that exhibits different bonding characteristics under different pressure conditions. The binder polymer remains unbonded at low pressure during rewinding but bonds effectively at high pressure during lamination, allowing the separator to adapt its bonding behavior to different operational stages.
2Strength
If high pressure is applied during lamination to ensure proper bonding, then bonding between electrode plate and separator is improved, but production efficiency decreases
Solution Approach 1:
The invention applies preliminary bonding action during the lamination process at high pressure, achieving sufficient bonding between electrode plate and separator in a single step. This eliminates the need for subsequent tunnel furnace treatment, thereby improving production efficiency while maintaining bonding quality.
Solution Approach 2:
The invention extracts and eliminates the tunnel furnace step from the production process by achieving sufficient bonding through pressure-sensitive lamination alone. This removal of unnecessary processing steps directly improves production efficiency while maintaining the required bonding quality.
3Strength
If tunnel furnace is used for bonding separator to electrode plate, then bonding quality is improved, but energy consumption increases and production time extends
Solution Approach 1:
The invention replaces the thermal system (tunnel furnace) with a mechanical system (pressure-sensitive lamination). Instead of using heat to achieve bonding, the invention uses pressure-sensitive binder polymer that bonds under mechanical pressure, thereby eliminating the need for high-energy thermal processing.
Solution Approach 2:
The invention changes the bonding parameter from temperature-based (tunnel furnace heating) to pressure-based (pressure-sensitive lamination). This parameter change eliminates the need for energy-intensive thermal processing while achieving equivalent or superior bonding quality.
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 prevents premature bonding during rewinding and storage, enhances bonding between electrode plates and separators, omits the need for a tunnel furnace, and improves kinetic and safety performance while increasing productivity by ensuring tight fits and reducing energy consumption.
Implementation Method 1
The pressure-sensitive binder polymer includes a binder polymer and a plasticizer... the separator bonds to an electrode plate substantially under a pressure greater than or equal to 2 MPa
Data Source
AI summary
A separator, a method for preparing the separator, a secondary battery (5) containing the separator, and an electrical device are described. The separator includes: a porous separator substrate; and a pressure-sensitive coating applied onto at least one surface of the separator substrate. The pressure-sensitive coating includes a first organic particle at a mass percent of 40 wt % to 90 wt %, a pressure-sensitive binder polymer at a mass percent of 10 wt % to 20 wt %, and optionally a second organic particle at a mass percent of 0 wt % to 50 wt %. The separator is of high ion-conductivity and high bonding performance at a normal temperature. The separator does not exert a bonding action under a pressure less than or equal to 1 MPa, but exerts a substantial bonding action under a pressure greater than or equal to 2 MPa, thereby significantly improving structural stability and ionic conductance of the electrochemical device.