Method of reclaiming cathodic active material of lithium ion secondary battery

• US 6,261,712 B1
• Filed: 06/23/1999
• Issued: 07/17/2001
• Est. Priority Date: 06/30/1998
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Sasaki, Kunihiko, Tezuka, Fuminobu, Tachibe, Tetsuya, Hayashi, Masaru, Tomioka, Yuki
• Primary Examiner(s): Kalafut, Stephen
• Assistant Examiner(s): Martin, Angela J.
• Application Number:
  US09/338,433
• Time in Patent Office: 755 Days
• Field of Search: 429/49, 429/231.95, 429/231.1, 429/231.3, 429/231.2, 423/179.5, 423/441, 423/50
• US Class Current: 429/49
• CPC Class Codes: H01M 10/05 Accumulators with non-aqueous electrolyte H01M10/39 takes precedence
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 10/54 Reclaiming serviceable parts of waste accumulators
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02W 30/84 Recycling of batteries or fuel cells

Abstract

Disclosed is a method of reclaiming a cathodic active material of lithium ion secondary batteries. The lithium ion secondary battery is broken and the casing and the content are separated to remove the casing from the content. The content is dissolved into a mineral acid to separate remaining non-dissolved content from the mineral acid to obtain a liquid containing the cathodic active material represented by the formula: LiMO₂, where M is a transition metal element: cobalt, nickel and manganese. A lithium salt is added to the liquid, and the cathodic active material is recovered from the liquid in the form of a mixture of lithium compound and the transition metal compound, which is calcined and reclaimed into the cathodic active material.

Claims

1. A method of reclaiming a cathodic active material of a lithium ion secondary battery having a casing and a content, said content comprising a cathodic active material represented by the formula LiMO₂, wherein M is a transition metal, comprising the steps of:

breaking the lithium ion secondary battery and separating the casing and the content to remove the casing from the content;

dissolving the content into a mineral acid to separate a remaining non-dissolved content from the mineral acid, thereby obtaining a liquid comprising the cathodic active material;

adding a lithium salt to the liquid; and

recovering the cathodic active material from the liquid by producing a precipitate comprising lithium and the transition metal of the cathodic active material from the liquid; and

separating and calcining the precipitate to reclaim a cathodic active material.

2. The reclaiming method of claim 1, wherein the transition metal is elected from the group consisting of cobalt, nickel and manganese.

3. The reclaiming method of claim 1, further comprising the steps of:

removing, from the liquid obtained at the dissolving step, a metallic impurity other than lithium and the transition metal of the cathodic active material.

4. The method of claim 3, wherein the removing step comprises:

precipitating or depositing the metallic impurity by pH control or electrolyzation of the prepared liquid.

5. The method of claim 4, wherein the precipitating or depositing step comprises:

adjusting the pH value of the liquid to approximately 6 to 8.

6. The method of claim 1, wherein, in the precipitate, the amount of lithium is in excess of the amount equimolar to the amount of transition metal of the cathodic active material.

7. The method of claim 1, wherein the producing step comprises:

alkalizing the liquid with an alkaline material comprising a carbonate compound.

8. The method of claim 1, wherein the producing step comprises the step of:

concentrating the liquid before the adding step.

9. The method of claim 7, wherein the lithium salt added at the adding step is selected from the group consisting of lithium hydroxide and lithium carbonate, the carbonate compound of the alkalizing step is selected from the group consisting of sodium carbonate, lithium carbonate and potassium carbonate, and the pH value of the prepared liquid at the alkalizing step is adjusted to approximately 10 or more.

10. The method of claim 7, wherein the pH value of the prepared liquid at the alkalizing step is adjusted to approximately 12 or more.

11. The method of claim 1, wherein the precipitate produced at the producing step comprises cobalt hydroxide carbonate:

Co(OH)(CO₂), and lithium carbonate;

Li₂CO₃.

12. The method of claim 1, wherein the recovering step further comprises, before the separating step, the steps of:

adding water to the liquid; and

digesting the liquid.

13. The method of claim 1, further comprising the step of:

cleaning the reclaimed cathodic active material with water to remove excess lithium.

14. The anodic active material reclaimed by the method of claim 1.

22. The reclaiming method of claim 1, wherein the mineral acid comprises sulfuric acid.

23. The reclaiming method of claim 7, wherein the carbonate compound of the alkalizing step is selected from the group consisting of sodium carbonate, lithium carbonate and potassium carbonate.

24. The reclaiming method of claim 7, wherein a pH value of the liquid in the alkalizing step is adjusted to 10 or more.

25. The reclaiming method of claim 7, wherein the pH value of the prepared liquid in the alkalizing step is adjusted to 12 or more.

15. A method of reclaiming a cathodic active material of a lithium ion secondary battery, wherein the cathodic active material comprises a lithium compound represented by the formula LiMO₂, where the letter M represents a transition metal selected from the group consisting of cobalt, nickel and manganese, the method comprising the steps of:

preparing a liquid in which the cathodic active material is dissolved;

adding a lithium salt into the prepared liquid;

producing a precipitate comprising lithium and the transition metal of the cathodic active material from the prepared liquid; and

separating and calcining the precipitate to reclaim a cathodic active material.

16. The method of claim 15, wherein the liquid prepared at the preparing step comprises a solution that the anodic active material is dissolved in an acidic liquid which includes mineral acid, and the producing step comprises:

alkalizing the prepared liquid with an alkaline material containing a carbonate compound, thereby the produced precipitate contains cobalt hydroxide carbonate;

Co(OH)(CO₃), and lithium carbonate;

Li₂CO₃.

17. The method of claim 16, wherein the mineral acid comprises sulfuric acid, and the method further comprises the step of:

removing, from the prepared liquid, a metallic impurity other than lithium and the transition metal of the anodic active material,

and the removing step comprises;

precipitating or depositing the metallic impurity by pH control or electrolyzation of the prepared liquid.

18. The method of claim 15, wherein, in the precipitate produced at the producing step, the amount of lithium is in excess of the amount that is equimolar to the amount of the transition metal of the cathodic active material, and the method further comprises the step of:

cleaning the reclaimed cathodic active material with water to remove excess lithium.

19. The method of claim 17, wherein the precipitating or depositing step comprises:

adjusting the pH value of the liquid to approximately 6.5.

20. The anodic active material reclaimed by the method of claim 15.

26. The reclaiming method of claim 17, wherein the precipitating or depositing step comprises adjusting the pH value of the liquid to 6.5.

21. A method of reclaiming a cathodic active material of a lithium ion secondary battery, wherein the cathodic active material comprises a lithium compound represented by the formula LiMO₂, where the letter M represents a transition metal selected from the group consisting of cobalt, nickel and manganese, the method comprising the steps of:

preparing a liquid in which the cathodic active material is dissolved;

adding a lithium salt into the prepared liquid;

producing, from the prepared liquid, a precipitate containing lithium and the transition metal of the cathodic active material such that the amount of lithium is in excess of the amount that is equimolar to the amount of the transition metal of the cathodic active material; and

separating and calcining the precipitate to reclaim a cathodic active material.