The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 05, 2000
Filed:
Nov. 13, 1998
Nobuhiro Takano, Hitachinaka, JP;
Kenrou Ishimaru, Hitachinaka, JP;
Toshio Mizoguchi, Hitachinaka, JP;
Shigeru Moriyama, Hitachinaka, JP;
Shigeru Shinohara, Mito, JP;
Hitachi Koki Co., Ltd., Tokyo, JP;
Abstract
A charging circuit generates a charging current from an ac supply which is supplied to a secondary battery in a battery package through first terminals. A second terminal receives a temperature detection signal from a thermistor on the secondary battery. A value of the temperature detection signal is sampled every predetermined interval. A memory stores the sampled value. A difference between the sampled value and the value from the memory is obtained, as well as the temperature decrease value between the sampled value and the value stored, when it applies. An error signal is generated when the difference is higher than a predetermined value and the operator is alarmed and informed of the error. The difference may be obtained between the sampled value and the value one-cycle-previously-sampled value from the memory, between the sampled value and a minimum of the sampled values, or between the sampled value and a charging start value of the sampled value. The thermistor is supplied with a supply voltage through a switch and an error condition caused by leakage of the electrolyte from the battery is detected when the voltage at the second terminal is higher than the predetermined value, the charging current generation circuit is controlled to stop generating the charging current.