Electric vehicle (EV) batteries are the engine of modern electric vehicle technology. They power the EV drivetrain and all vehicle functions, including cabin heating, steering, and brake systems.
As global adoption accelerates, the manufacturing technology and processes used to create lithium-ion electric vehicle batteries are becoming increasingly efficient as OEMs strive to achieve profitability within this new manufacturing frontier.
Competition among domestic start-ups and legacy automotive manufacturers with global footprints will continue to increase, driving down EV prices and achieving progress toward consumer affordability.
In parallel, policymakers worldwide continue to advocate for sustainable transportation options. They are likely to continue to support the relatively new product class of EVs and infrastructure as manufacturers innovate to meet consumer preferences.
The advances in manufacturing technologies spurred by the shift towards EVs will continue to benefit manufacturers and consumers of EVs and consumer products powered by such battery technologies.
Key Steps in the Lithium-Ion Battery Manufacturing Process
The lithium-ion battery manufacturing process is complex, involving many steps that require precision and care. This brief survey focuses primarily on battery cell manufacturing, from raw materials to final charging checks.
Step 1: Raw Material Preparation
The first step in the EV’s upstream supply chain involves mining and processing raw materials.
Lithium-ion batteries require five key raw materials or minerals:
- Lithium
- Cobalt
- Nickel
- Manganese
- and Graphite.
After being mined from the earth, these minerals are processed and refined into usable raw materials for battery manufacturing. Mining and refining these minerals into usable, high-quality powders is energy-intensive and difficult.
Step 2: Electrode Production
The raw materials, such as lithium powder, are mixed with chemical binders, solvents, and other additives to form a slurry mixture. This mixture is then coated onto a metal backing foil called the collector, usually aluminum for the cathode and copper for the anode. This subassembly is then dried in ovens to dry and bind the slurry to the metal foil.
Then, the bonded foil undergoes a calendaring process, which involves compressing the dried electrode under large industrial rollers to smooth it and compress it into the desired thickness.
The last step in the electrode production process involves cutting the coated foils into the requisite shapes suitable for the battery cells.
Step 3: Cell Assembly
For prismatic battery cell assembly, the electrode subassemblies are stacked carefully with alternating separator materials required to prevent short-circuiting of the cells.
The stacked subassemblies are then inserted into cell casings made from either steel, plastic, or ceramic to provide robust protection to the electrical components.
The protruding electrode ends of the battery cells are welded to terminals outside the casing to facilitate electrical connectivity.
Step 4: Electrolyte Filling and Sealing
The next step in producing battery cells involves filling the cell assemblies with the electrolyte solution. This solution is most commonly a liquid solution of lithium salts and an organic solvent.
The addition of the electrolyte solution permits the free movement of ions between the anode and cathode portions of the battery cell. The cells are hermetically sealed to prevent electrolyte leakage and contamination from external particulates.
In most EV battery cell manufacturing, sealing is performed under a vacuum to remove air bubbles from the solution.
Step 5: Formation and Aging
The formation process involves carefully charging and discharging the cells in a controlled fashion. This process creates a solid electrolyte interface (SEI) layer that helps ensure battery longevity and stability.
The next step is an aging process where the battery cells are charged and discharged at a controlled rate at an elevated temperature under careful monitoring to detect failures and stabilize battery performance.
Finally, remaining performance tests are performed to verify that the battery cells meet safety standards before being assembled into modules.
Final Steps: Module and Pack Assembly and Vehicle Integration
The final steps involve assembling the battery cells into modules and the EV battery pack. After this, the battery pack is assembled into a protective housing in the vehicle and linked to various EV support systems, such as cooling and battery management software.
For even more information on these final steps, including battery module assembly, pack assembly, and integration into the vehicle, check out our supporting summary of EV battery pack manufacturing and our general description of how EV battery packs power vehicle systems.
Advanced Techniques in EV Battery Cell Production
Advances in manufacturing technology, specifically lithium-ion battery production techniques, have proven revolutionary for all consumer products in the battery space.
Here are a few of the most notable areas of advancement.
Automation
Many EV manufacturers use automation, such as robotic systems outfitted with machine vision capabilities, to efficiently perform pick-and-place operations during battery cell assembly, including sorting and assembling cells into modules.
These advanced robotic systems can recognize cells and determine their placement within assemblies according to their appearance.
Robotic systems are also used for laser welding and bonding operations to produce fast, high-quality welds and bonds.
Design for Manufacturability
EV manufacturers are developing ways to optimize EV pack design concepts and simplify their assembly.
One notable concept is the cell-to-pack configuration, which aims to manufacture EV battery packs by directly integrating battery cells. This should achieve a higher energy density and significantly reduce manufacturing complexity.
Sustainability
OEMs are putting significant effort into planning for the whole lifecycle of the EV battery pack to determine how to recycle key materials within depleted battery pack assemblies.
Automated systems on the manufacturing floor are being developed to extract usable materials efficiently from scrapped EV batteries.
Additionally, OEMs carefully plan battery production buildings and infrastructure to use renewable energy sources wherever possible to bring sustainability to the facility.
Conclusion
MISUMI supports all your EV battery manufacturing needs, from cell to final pack to electric vehicle integration.
Whether you need to source high-quality components or leverage the expertise of our engineering team, we provide the tools and guidance to optimize your production process.
