Electricity: battery or capacitor charging or discharging – Serially connected batteries or cells – Having variable number of cells or batteries in series
Reexamination Certificate
1997-07-03
2001-05-29
Wong, Peter S. (Department: 2838)
Electricity: battery or capacitor charging or discharging
Serially connected batteries or cells
Having variable number of cells or batteries in series
C320S119000, C324S426000
Reexamination Certificate
active
06239579
ABSTRACT:
BACKGROUND TO THE INVENTION
The present invention relates to a device for directly monitoring, assessing and managing the useful capacity and health of batteries.
The invention may be used in conjunction with any device or system which is battery-powered, or which uses a battery pack as an alternative or back-up power source, such as railway level crossing and switch systems; mobile electronic equipment battery packs used in cellular telephones, computers, camcorders; electric vehicles; computers; telecommunication or station batteries; telephone switching facilities and portable test equipment.
Battery users currently have no accurate means for determining the useful capacity of batteries, e.g. those used as a back up for a primary AC power source. Conventional devices measure voltage, impedance, electrolyte specific gravity or other battery characteristics, but do not provide the user with direct information concerning the length of time the battery will operate under load.
In a preferred embodiment, the invention enables the capacity and health of a battery to be assessed, monitored and managed from a remote site.
By way of example, the present invention has utility as a safety device for integration with systems which operate railroad crossings. Safety at railroad crossings has become a major source of railway liability over the last ten years. In accordance with established safety guidelines, some jurisdictions require railroad companies to guarantee a minimum number of hours of direct current (DC) backup power to the power gate arms and flashing warning lights located at these level crossings. Such regulations have heightened the need for enhanced battery management systems.
As a preventive measure, many level crossings in North America have been equipped with a device known as a Crossing Analyzer (“CA”). A Crossing Analyzer is a computer controlled data application system which records the amperage draw of each light and the position and amperage draw of each gate at the level crossing. The CA is also fitted with a modem to forward alarms to a central monitoring station should there be a problem. In fact, one railroad company is so concerned about the safety of their level crossings that they have programmed their CA's to dial in every twenty-four hours, to provide a constant monitoring of the system. If a call is not received for a particular level crossing, a railway maintainer is dispatched to diagnose the problem immediately.
In the event of an AC power failure, it is essential that the DC battery back-up power operate efficiently and at the required capacity. To date, there has been no practical method to load test a back-up battery at a remote site.
SUMMARY OF THE INVENTION
The present invention addresses the disadvantage inherent in the prior art by providing a device for directly assessing the useful capacity of a back-up battery, even where the battery is located at a remote site and without compromising the ability of the back-up battery to operate should there be an AC power failure during the battery testing.
This objective is achieved by performing a sequential, individual assessment of each module which comprises a battery pack. Where used in this specification, the term “module” means one or more electrochemical cells.
A further advantage of the present invention arises from its capability to rejuvenate or boost the health of the battery module of certain chemistries, e.g. nickel/cadmium. The discharge/charge sequence which is carried out in order to assess and monitor the useful capacity of the module, also serves to better cycle the module.
In one aspect, the invention provides a system for directly assessing the useful capacity of an online battery pack, comprising: a programmable logic controller operatively connected to a monitor circuit and to one or more battery modules comprising said battery pack, said monitor circuit comprising battery module charging means, and discharge load means; wherein said programmable logic controller selectively and sequentially opens and closes a plurality of relays which connect with said charging means and said discharge load means to alternatively define a discharge circuit which enables one of said modules to be discharged by said discharge load means under a predefined load, the useful capacity of said module being calculated by said programmable logic controller.
In a second aspect, the invention provides a device for directly assessing the useful capacity of at least one battery module within a battery pack, comprising: a programmable logic controller operatively connected to a plurality of battery modules comprising a battery pack, battery module charging means, and discharge load means; wherein each of said modules may be selectively isolated from the other said cells defining said battery pack, by the opening and closing of relays which connect said modules with said discharge load means and said battery module charging means, enabling said module to be selectively and sequentially discharged by said discharge load means and then recharged by said battery module charging means.
Preferably, the programmable logic controller comprises, or is operatively connected to at least one module voltage reader; battery pack current reader and module current reader; a switch controller to control said isolation relays; a controller for said variable discharge load means and said single module battery charger (charger/discharger controller).
In an additional aspect, the invention provides a method of sequentially assessing the operating capacity of a plurality of battery modules which define a battery pack, which comprises the steps of:
selecting one of said modules for assessment;
connecting said selected module to a variable discharge load means by closing relays which connect said module to said variable discharge load means;
measuring parameters which define the useful capacity of said module, while said module is under load;
disconnecting said selected module from said variable discharge load means by opening said relays and either; (a) connecting said selected module to a battery charger for recharging; and (b) reconnecting said selected module to said plurality of modules by the selective opening and closing of relays which connect said modules with said battery charger, and said variable discharge load;
wherein the coordination of all of the above steps is accomplished by the use of a programmable logic controller operatively comprising, in combination, at least one voltage reader; at least one battery pack current reader; at least one module current reader; and a switch controller to control the opening and closing of said relays.
In a further aspect, the invention provides a method of sequentially assessing the useful capacity of a plurality of battery modules which define a battery pack, which comprises the steps of:
selecting one of said modules for assessment;
connecting said selected module to a variable discharge load means by closing relays which connect said module to said variable discharge load means;
measuring parameters which define the useful capacity of said module, while said module is under load;
determining whether said useful capacity meets a predefined threshold for useful capacity;
disconnecting said selected module from said variable discharge load means by opening said relays and either;
recharging said selected module by connecting said selected module to a battery charger where said useful capacity meets said predefined threshold; or generating a signal where said useful capacity does not meet said predefined threshold;
wherein the above steps are coordinated by a programmable logic controller operatively comprising, in combination, at least one voltage reader; at least one battery current reader; at least one module current reader; and a switch controller to control the opening and closing of said relays.
Where the useful capacity of the selected module satisfies the threshold, the selected module is reinserted into the circuit which defines the battery pack by reconnection of the se
de Oliveira Julio C.
Dunn James H.
Gerwing David H.
Estco Battery Management Inc.
Toatley Gregory J.
Wilkes Robert A.
Wong Peter S.
LandOfFree
Device for managing battery packs by selectively monitoring... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device for managing battery packs by selectively monitoring..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device for managing battery packs by selectively monitoring... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2463049