Fluidized Bed Sifting for Lithium Iron Phosphate Contaminant Removal
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Solution Overview
Problem
Existing methods for producing lithium iron phosphate for lithium ion batteries are inefficient in removing particulate contaminants, leading to increased self-discharge and failure rates due to residual metallic and oxidic particles, which conventional fluidized bed sifting techniques fail to effectively remove.
Innovation Solution
A method involving fluidizing and sifting particulate mixed lithium metal phosphate material in a fluidized bed, with intermittent feeding and continuous processing until the material mass is reduced to 10-100% of the initial mass, followed by removal of residual material, effectively reducing contaminant levels to less than 0.1 ppm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fluidized bed sifting techniques are used to remove particulate contaminants, then the processing speed is maintained, but the contaminant removal efficiency is insufficient leading to residual metallic and oxidic particles
Solution Approach 1:
The patent implements periodic action by intermittently stopping the feed of particulate material into the fluidized bed sifter at regular intervals (e.g., after processing 10-100 times the bed volume). During these stop periods, the sifter continues to operate to remove contaminants without new material entering, allowing accumulated contaminants to be selectively removed. This periodic interruption significantly improves contaminant removal efficiency while maintaining overall processing throughput by quickly resuming feed after each stop.
2Reliability
If the feed is continuously maintained to maintain productivity, then the processing speed is high, but the contaminant removal efficiency decreases due to constant material input
Solution Approach 1:
The patent applies partial action by discontinuing the feed only intermittently rather than continuously stopping. The feed is stopped for limited periods (after processing 10-100 times the bed volume) to allow contaminant removal, then resumed. This partial interruption approach achieves effective contaminant removal without sacrificing overall processing time, as the stop periods are relatively short compared to the total processing cycle.
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 significantly reduces particulate contaminant levels in lithium iron phosphate to less than 0.1 ppm, improving the reliability and performance of lithium ion cells by effectively removing metallic and oxidic impurities.
Implementation Method 1
feeding the particulate mixed lithium metal phosphate material into a fluidizing stage and fluidizing it in the fluidizing stage
Implementation Method 2
feeding the fluidized particulate mixed lithium metal phosphate material to a sifting stage and passing it through the sifting stage
Data Source
AI summary
A method for removing a particulate contaminant material from a particulate mixed lithium metal phosphate material is provided. The method includes feeding the particulate mixed lithium metal phosphate material into a fluidizing stage containing particulate mixed lithium metal phosphate material of mass m, feeding the fluidized particulate mixed lithium metal phosphate material through a sifting stage, discontinuing the feed of the particulate mixed lithium metal phosphate material into the fluidizing stage after 10 to 100 times of the mass m have been fed into the fluidizing stage, fluidizing and sifting the material present in the fluidizing stage after discontinuing the feed until the mass of the material present in the fluidizing stage becomes 10% to 100% of the mass m, and removing the remaining material from the fluidizing stage.