The battery assembly requirements for new and used electric vehicles (EVs) differ primarily due to the manufacturing processes, testing, and reconditioning involved.
New EV Battery Assembly Requirements
- Cell-Level Manufacturing and Assembly: New EV battery assembly begins at the single cell level, where the anode, cathode, separator, and electrolyte are combined inside a sealed housing. Each cell undergoes rigorous testing for leaks and moisture ingress to ensure safety and performance.
- Foil-to-Tab Welding and Electrical Connections: Metal strips are welded to cell electrodes to create electrical connections, typically using ultrasonic bonding or laser welding, followed by tab-to-busbar joining to form modules.
- Electrolyte Filling, Degassing, and Sealing: Electrolyte is carefully poured and absorbed by separators, with vacuum degassing to remove air bubbles ensuring uniform electrolyte distribution. The cell casing is hermetically sealed via crimping, laser welding, or ultrasonic bonding.
- Forming and Initial Charging Cycles: Cells undergo multiple charge-discharge cycles with resting phases (forming) to set optimal electrochemical properties.
- Inspection and Grouping: Cells are visually and electrically inspected, and those with similar performance characteristics are grouped into modules for consistent module-level performance.
- Final Assembly into Modules and Packs: Modules are assembled into battery packs, designed to meet the vehicle’s power and size requirements.
This detailed, controlled process ensures new batteries meet strict performance, safety, and durability standards before installation in a new EV.
Used EV Battery Assembly or Reassembly Requirements
- Reconditioning and Testing: Used EV batteries, typically from end-of-life or retired vehicles, require comprehensive testing of cell health, capacity, and internal resistance to identify and isolate weaker cells.
- Cell Matching and Replacement: Cells with degraded performance are replaced or repaired. Remaining cells are sorted and regrouped to ensure uniformity within assembled modules, similar to new cell grouping but often more challenging due to variability in used cells.
- Safety and Integrity Checks: Since used batteries may have experienced wear, additional inspections for leaks, moisture ingress, and mechanical damage are critical before reassembly.
- Reassembly into Modules and Packs: Modules are reassembled into packs, potentially with modified configurations to optimize remaining battery life and performance for secondary use cases, such as energy storage.
- Certification and Compliance: Used batteries may require compliance with evolving regulations or certification programs to validate safety and functionality for reuse.
Summary
| Aspect | New EV Battery Assembly | Used EV Battery Reassembly |
|---|---|---|
| Cell Source | Newly manufactured, pristine cells | Previously used cells, reconditioned or replaced as needed |
| Testing and Inspection | Initial quality and performance testing, grouping | Health diagnostics, identification of weak cells, sorting |
| Assembly Process | Controlled manufacturing steps (welding, filling, forming) | Additional safety checks, refurbishment, replacement of cells |
| Safety Measures | Leak and moisture checks during initial manufacturing | Enhanced safety inspections due to prior use |
| Final Configuration | Designed for new vehicle specs and performance | Customized pack construction for residual capacity and use |
| Regulatory Compliance | Compliance with new vehicle standards and certifications | May require certification for second-life or resale use |
In essence, the battery assembly for new EVs involves manufacturing cells from scratch and precise assembly under controlled conditions, whereas for used EVs, assembly focuses on inspection, testing, refurbishment, and configuring existing cells for safe, effective reuse. This ensures performance and safety are maintained despite the different lifecycle stages of the battery systems.
Original article by NenPower, If reposted, please credit the source: https://nenpower.com/blog/how-do-the-battery-assembly-requirements-differ-for-new-and-used-evs/
