Electrode Stack Heat Press Sequencing to Prevent Distortion
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Solution Overview
Problem
The existing methods for manufacturing electrode assemblies in secondary batteries face challenges such as electrode distortion and mechanical part deformation during the manufacturing process, particularly due to the folding of separators in a zigzag manner.
Innovation Solution
A method involving the stacking of electrodes with a separator, followed by a primary heat press operation, a pre-heating operation, and a secondary heat press operation, to bond the electrodes to the separator without individually heating and pressing each level, thereby preventing distortion and deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If separators are folded in a zigzag manner to bond electrodes, then electrode assembly is formed, but electrode distortion and mechanical part deformation occur
Solution Approach 1:
The bonding process is divided into three distinct stages: primary heat press operation, pre-heating operation, and secondary heat press operation. Each stage serves a specific function - the primary operation provides initial bonding, the pre-heating operation prevents distortion by controlled heating, and the secondary operation completes the bonding. This segmentation resolves the contradiction by allowing electrode assembly formation while maintaining position accuracy through staged processing.
Solution Approach 2:
The pre-heating operation is performed between the primary and secondary heat press operations to preliminarily heat the electrode stack before final bonding. This preliminary action prevents electrode distortion and mechanical part deformation by controlling thermal expansion before the final bonding pressure is applied, thus maintaining manufacturing precision while enabling assembly formation.
2Reliability
If individual heating and pressing is performed at each level, then bonding is achieved, but manufacturing time increases
Solution Approach 1:
Multiple bonding operations are merged into a single integrated process where the primary heat press operation, pre-heating operation, and secondary heat press operation are performed sequentially on the entire electrode stack as one unit. This combining approach achieves reliable bonding throughout the assembly without the need for separate operations at each level, thereby maintaining productivity while ensuring bonding quality.
3Productivity
If heat and pressure are applied continuously, then bonding efficiency is improved, but electrode distortion occurs
Solution Approach 1:
The bonding process uses periodic action with three distinct phases: primary heat press operation, pre-heating operation, and secondary heat press operation. The pre-heating operation acts as an intermediate phase that prevents distortion by controlled heating before the final bonding pressure. This periodic approach maintains bonding efficiency while preserving electrode shape accuracy through rhythmic application of heat and pressure.
Solution Approach 2:
The process changes parameters between operations - the pre-heating operation uses controlled temperature increase without full bonding pressure, then the secondary heat press operation applies full pressure for complete bonding. This parameter change strategy prevents electrode distortion by avoiding continuous high pressure while maintaining bonding efficiency through staged parameter adjustment.
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 method effectively prevents electrode distortion and mechanical part deformation, ensures uniform adhesive force and air permeability across the electrode assembly, and reduces manufacturing time while improving energy density.
Implementation Method 1
performing a primary heat press operation on the electrode stack... In each of the primary and secondary heat press operations, heat and pressure may be applied to the electrode stack
Implementation Method 2
performing a pre-heating operation on the electrode stack... The pre-heating operation may include applying heat and pressure to the electrode stack for a time period from 10 seconds to 40 seconds under a pressure condition from 0.5 MPa to 2 MPa and under a temperature condition from 50° C. to 85° C.
Implementation Method 3
performing a secondary heat press operation on the electrode stack... then performing a secondary heat press operation on the electrode stack
Data Source
AI summary
An electrode assembly manufacturing method includes the steps of: assembling an electrode stack; performing a primary heat press operation on the electrode stack; then performing a pre-heating operation on the electrode stack; and then performing a secondary heat press operation on the electrode stack. The pre-heating operation may include applying heat and pressure to the electrode stack for a time period from 10 seconds to 40 seconds under a pressure condition from 0.5 MPa to 2 MPa and under a temperature condition from 50° C. to 85° C. The pressure condition applied in the pre-heating operation may include applying a lower pressure than that applied in the primary and secondary heat press operations. The primary heat press operation may include engaging the electrode stack with a gripper to secure a position of the electrode stack, which gripper may be disengaged from the electrode stack before performing the pre-heating operation.