Underwater discharge device and method for waste lithium-ion batteries

Continuous underwater discharge system for waste batteries combining localized casing damage with electrolyte circulation and recovery

This technology safely discharges waste lithium-ion batteries by passing them through compression rollers to create precise micro-cracks in the casing side, rather than shredding the entire unit. This allows water to slowly enter the electrolyte without damaging the separator.

Conventional saltwater immersion methods are excessively slow, while electrical resistance methods suffer from low efficiency due to the need for individual setups per battery. Furthermore, traditional shredding methods risk fire and explosion by damaging the separator.

This technology uses a pair of compression rollers set 1–10mm narrower than the battery thickness to induce cracks at the casing joints, followed by continuous underwater discharge and electrolyte recovery via a filtration line. Ideal for EV battery dismantling plants and collection hubs, it completes discharge in under 5 minutes, increasing throughput while minimizing water contamination from electrolyte leakage.

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Key Features:

• A pair of compression rollers spaced apart and rotating in opposite directions to compress incoming waste lithium-ion batteries and damage one side of the casing
• A discharge tank filled with water that receives and discharges the waste lithium-ion batteries damaged by the compression rollers
• An electrolyte recovery unit connected to the discharge tank's drain line to filter the electrolyte and return purified water to the tank
• A conveyor belt transport unit arranged at an upward incline, with one end positioned directly below the compression rollers at the bottom of the tank and the other at the top

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This invention was developed with support from the Ministry of Trade, Industry and Energy for the development of advanced hydrometallurgical technologies to increase the value of recovered resources.

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