Method and apparatus for recycling lithium iron phosphate batteries

Patent metadata

Field	Value
Publication number	US-2018261894-A1
Application number	US-201815976981-A
Country	US
Kind code	A1
Filing date	May 11, 2018
Priority date	Apr 4, 2012
Publication date	Sep 13, 2018
Grant date	—

Abstract

Cathode material from exhausted lithium ion batteries are dissolved in a solution for extracting the useful elements Co (cobalt), Ni (nickel), Al (Aluminum) and Mn (manganese) to produce active cathode materials for new batteries. The solution includes compounds of valuable charge materials such as cobalt, nickel, aluminum and manganese dissolved as compounds from the exhausted cathode material of spent cells. However, LiFePO 4 is a waste stream charge material often discarded due to infeasibility of recycling. LiFePO4 is precipitated as FePO4 and remains as a by-product, along with graphite and carbon, which are not dissolved into the solution. FePO 4 can be separated from graphite and carbon, FePO 4 can be used to synthesize LiFePO 4 as cathode materials and graphite can be regenerated as anode materials.

First claim

What is claimed is:

1 . A method for recycling lithium iron phosphate batteries, comprising
removing solid battery components including casing and electrode materials from exhausted lithium ion batteries (LIBs) by physical separation resulting in a granular mass of exhausted charge materials including carbon, graphite and iron phosphate; adding an inorganic acid to the granular mass to separate graphite and carbon from the iron phosphate to yield a solution of iron chloride and phosphoric acid with undissolved carbon and graphite; adjust a pH of the iron chloride and phosphoric acid solution to precipitate an iron phosphate precursor; combining lithium carbonate with the precipitated iron phosphate by agitation; and sintering the combined mixture of lithium carbonate and iron phosphate to yield cathode powders adapted for use as charge materials.

2 . The method of claim 1 further comprising sintering the combined mixture to generate LiFePO 4 charge material.

3 . The method of claim 1 further comprising precipitating the iron phosphate by circulating and heating a reactor containing the iron chloride and phosphoric acid solution to precipitate iron phosphate in a powder form.

4 . The method of claim 1 further comprising combining a carbon source and lithium carbonate with the precipitated iron phosphate by agitation, the carbon source including at least glucose or sucrose.

5 . The method of claim 4 further comprising adding carbon source in an amount based on 20% of the iron phosphate.

6 . The method of claim 1 wherein the inorganic acid is 5M hydrochloric acid.

7 . The method of claim 1 further comprising adding ammonium hydroxide to the reactor for maintaining the pH substantially at 2.

8 . The method of claim 7 further comprising controlling the pH in a range between 1.5-4.5.

9 . The method of claim 1 further comprising adding a stoichiometric amount of lithium carbonate to the yield the lithium iron phosphate charge material.

10 . The method of claim 1 further comprising acid leaching charge material compounds other than iron phosphate from the granular mass prior to adding the inorganic acid.

11 . The method of claim 1 further comprising adjusting the pH from the addition of ammonium hydroxide or sodium hydroxide.

12 . A method for recycling lithium iron phosphate batteries, comprising
removing solid battery components including casing and electrode materials from exhausted lithium ion batteries (LIBs) by physical separation resulting in a granular mass of exhausted charge materials including carbon, graphite and residual cathode materials; adding a first inorganic acid to the granular mass for leaching charge materials other than iron phosphate from the exhausted charge materials; directing a leach solution resulting from the leached charge materials to a recycling stream; adding a second inorganic acid to the remaining granular mass to generate a leach solution including iron chloride and phosphoric acid and leave carbon and graphite undisturbed; adjusting the pH of the generated leach solution to precipitate an iron phosphate precursor, the iron phosphate precursor responsive to lithium carbonate and sintering for forming lithium iron phosphate.

13 . The method of claim 12 wherein the second inorganic acid is hydrochloric acid.

14 . The method of claim 12 wherein the first inorganic acid is sulfuric acid, and the leached charge materials include nickel, manganese and cobalt.

15 . The method of claim 12 wherein the physical separation includes:
agitation and crushing to separate casing and containment materials;
sorting and magnetic separation to remove casing and current collector metals from the charge material.

16 . The method of claim 12 further comprising removing exhausted charge materials including nickel, manganese and cobalt from dissolution in the leached charge materials.

17 . The method of claim 12 further comprising forming a leach solution by adding an inorganic acid to crushed battery materials defining the granular mass to form a leach solution including compounds of nickel, manganese and cobalt reacted with the inorganic acid.

18 . The method of claim 17 further comprising processing the leach solution for forming a parallel recycling stream for recycling the leached charge materials.

19 . The method of claim 12 wherein the first inorganic acid dissolves at least one of nickel, manganese and cobalt charge materials and is substantially nonreactive with the iron phosphate charge materials.

Assignees

• Worcester Polytech Inst

Inventors

• Wang Yan
• Ma Xiaotu

Classifications

• H01M4/5825

  Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines · CPC title

• H01M2004/028

  Positive electrodes · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• C01B25/45 Primary

  containing plural metal, or metal and ammonium · CPC title

• H01M10/54 Primary

  Reclaiming serviceable parts of waste accumulators · CPC title