Method and device for judging the condition of secondary batteries and method for regenerating secondary batteries

• US 7,180,298 B2
• Filed: 05/18/2005
• Issued: 02/20/2007
• Est. Priority Date: 08/10/1998
• Status: Expired due to Fees

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Nakamura, Kenji, Ito, Takashi, Minohara, Taketoshi
• Primary Examiner(s): TIBBITS, PIA FLORENCE
• Application Number:
  US11/131,279
• Publication Number:
  US 20050208368A1
• Time in Patent Office: 643 Days
• Field of Search: 320/132, 429/21, 429/27, 429/67, 429/69, 429/49, 324/432
• US Class Current: 324/432
• CPC Class Codes: G01R 31/389 Measuring internal impedance, internal conductance or related variables
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health
• CPC Class Codes: H01M 10/4242 Regeneration of electrolyte or reactants
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

By measuring the average thickness of the oxide layer, regardless of the specification of the battery, the level of the degradation of the negative electrode can be accurately determined. With the present regenerating method, the reducing agent is prevented from being adding to the electrolyte when the level of the degradation is low, or only the electrolyte is prevented from being supplemented when the level of the degradation is high. Thus, the battery performance can be recovered effectively.

Claims

1. A method for regenerating a secondary battery comprising the steps of:

only supplementing an electrolyte when the level of the degradation of a negative electrode is determined to be low, and the average thickness of said oxidized layer which is formed on said surface of said active material of said negative electrode is less than a predetermined standard, and

adding a reducing agent to said electrolyte when the level of the degradation of said negative electrode is determined to be high, and the average thickness of said oxidized layer is a predetermined standard or more, wherein said standard is the average thickness of said oxidized layer, which is measured at the time the discharge capacity of a reference battery equivalent to the secondary battery rapidly decreases or the internal resistance of the reference battery rapidly increases.

2. A method as claimed in claim 1, wherein the average thickness of said oxidized layer as said standard is 1000 nm.

3. A method as claimed in claim 1, wherein said secondary battery is a nickel-hydrogen battery including a negative electrode of which a negative electrode active material is a hydrogen-occluding alloy, and an electrolyte interposed between a positive electrode and said negative electrode.