ECS-R Ambient Electrolyte Injection & Vacuum Standing Machine with Dual Chamers for Cylindrical Cells, ERCCAEIVSM

An Ambient Electrolyte Injection & Vacuum Standing Machine is a critical piece of hardware in cylindrical cell assembly lines (such as 18650, 21700, or 4680 formats). Its primary purpose is to precisely dose the highly volatile, sensitive electrolyte into the cell casing under ambient pressure, and then use cyclic vacuum holding (standing) to force the liquid into the tightly wound jellyroll.

The process is generally divided into two distinct chambers or sequential modules: the Injection Station and the Vacuum Standing Station.

Liquid Injection Stage: (1) Precision Dosing: High-precision ceramic pumps (often utilizing linear motors or stepping motors) measure the exact electrolyte volume, typically within an accuracy of ±0.5% to ±1%. (2) Ambient Control: While injection occurs at atmospheric/ambient pressure within the machine, the environment inside the chamber is strictly maintained with an ultra-dry atmosphere (typically a dew point below -40°C to -60°C) to prevent the electrolyte (LiPF6 or NaPF6) from reacting with moisture to form highly corrosive hydrofluoric acid (HF). (3) Anti-Drip Nozzles: Specialized vacuum-suction nozzles prevent any residual drops from contaminating the cell rim, which would interfere with the subsequent cap welding/sealing process.

Vacuum Standing Stage (Wetting): Because cylindrical cells feature a tightly wound jellyroll (cathode, anode, and separator compressed together), the electrolyte cannot easily permeate the core via gravity alone. (1) Air Evacuation: The machine seals the cell cup and draws a vacuum. This evacuates the micro-voids and air pockets trapped between the electrode layers and the separator. (2) Pressure Differential Drive: By abruptly breaking the vacuum or cycling between vacuum and atmospheric pressure, a strong pressure differential forces the electrolyte deep into the pores of the electrodes and the separator framework. (3) Multi-Stage Stepped Vacuum: Advanced machines utilize a programmable, multi-stage profile (e.g., pulling down to -95 kPa, holding, bumping to -50 kPa, and returning to 0 kPa) to accelerate complete wet-out without causing the electrolyte to boil or froth.

References:

1. T. Knoche, et al., In situ visualization of the electrolyte solvent filling process by neutron radiography, J. Power Sources, 2016, 331, 267-276
2. F. J. Günter, et al., Influence of the Cell Format on the Electrolyte Filling Process of Lithium-Ion Cells, Energy Technology, 2020, 8, 1801108.
3. H. Cui, et al., Operando monitoring of the open circuit voltage during electrolyte filling ensures high performance of lithium-ion batteries, Nano Energy, 2022, 104, 107874.