Apparatus and method for monitoring state of battery

• US 5,600,566 A
• Filed: 12/28/1994
• Issued: 02/04/1997
• Est. Priority Date: 02/28/1994
• Status: Expired due to Fees

• Current Assignee: Volvo Construction Equipment Holding Sweden AB
• Original Assignee: Samsung Heavy Industries Company Limited (Samsung Group)
• Inventors: Park, Yong-Sik
• Primary Examiner(s): Cosimano, Edward R.
• Application Number:
  US08/364,933
• Time in Patent Office: 769 Days
• Field of Search: 320/15, 320/16, 320/17, 320/18, 320/43, 320/48, 340/636, 364/481, 364/483
• US Class Current: 702/63
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements
• CPC Class Codes: G01R 31/396 Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery
• CPC Class Codes: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: H02J 7/005 Detection of state of health [SOH]
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y10S 320/21 State of charge of battery

Abstract

An apparatus and a method for monitoring the state of a battery are disclosed in which a micro-processor is used to accurately measure the current state of a battery used for supplying electric power in electric automobiles and the like. The present invention includes: a plurality of passive modules with a micro-processor installed thereon for measuring the charge state of respective batteries; an active module for measuring the overall state of the batteries and for supervising the respective passive modules; and serial lines for connecting the passive modules and the active module. The passive modules compute the charge/discharge states of the respective batteries within certain time intervals to record the data into an internal RAM. The active module measures the overall charge/discharge state of the total batteries within certain time intervals, and receives the data on the charge/discharge states of the individual batteries through the serial communications. Then the active module compares these data to compute the overall battery residual capacity. With the present invention, the maintenance and wiring are easy to implement, and the exact time for charging the batteries can be known, thereby extending the life expectancy of the batteries.

Claims

1. An apparatus for monitoring a battery charge state comprising:

a plurality of passive modules comprising an A/D converter for converting analog signals of voltages, currents and temperatures of a plurality of batteries into digital signals within time intervals, a micro-processor including an internal RAM, a ROM, a clock and a serial port for computing a battery charge state of the batteries based on an output of said A/D converter, and a plurality of displays for displaying the battery charge state of the batteries computed by said micro-processor;

an active module comprising a micro-processor for computing a residual capacity of the batteries by obtaining information from individual passive modules of said plurality of passive modules, a storing means for storing the information from said passive modules, an auxiliary memory means for storing the information from said passive modules when the apparatus is off, and a display for displaying the residual capacity of the plurality of the batteries; and

two serial lines for connecting said plurality of passive modules and said active module.

2. A method for monitoring a residual capacity of a plurality of batteries with an apparatus including a plurality of passive modules for measuring a charge state of said plurality of batteries, an active module for measuring the residual capacity of the batteries, and two serial lines for connecting the plurality of passive modules and said active module comprising:

carrying out an individual battery charge state measuring step with said passive modules, including the sub-steps of checking an existence of any defective batteries, converting analog signals of voltages, currents and temperatures of the plurality of batteries into digital signals by utilizing an A/D converter, and computing a charge state based on an already modelled charge/discharge function, computing expected charge/discharge amounts based on charge/discharge ratios for respective ones of the plurality of batteries, comparing the expected charge/discharge amounts with a value obtained from the already modelled function so as to compute adjusted battery charge states, and storing computed charge state values into an internal RAM, and displaying the adjusted battery charge states with a display; and

carrying out an overall battery charge state measuring step with said active module including the sub-steps of converting the analog signals of the voltages, currents and the temperatures of the plurality of batteries into digital signals, polling said passive modules to collect information on any defectiveness, charge states, temperatures, voltages, currents and current directions of the plurality of batteries, and storing the collected information in a RAM, computing the residual capacity of the plurality of batteries based on values measured by said passive modules and based on collected information values, comparing respective measured values of residual capacity of each battery with computed values of the residual capacity of each battery so as to compute the overall residual capacity of each of the plurality of batteries, and displaying the computed residual capacity of each of the plurality of batteries with a display.