Method, arrangement and interface system to enable electrical batteries of different kinds to be charged by means of the same charger device

• US 6,441,583 B1
• Filed: 10/22/2001
• Issued: 08/27/2002
• Est. Priority Date: 10/23/2000
• Status: Expired due to Fees

• Current Assignee: Saft Finance Sarl (Totalenergies Se)
• Original Assignee: Alcatel SA (Nokia Corporation)
• Inventors: Perelle, Michel
• Primary Examiner(s): Vu, Bao Q.
• Assistant Examiner(s): LUK, LAWRENCE W
• Application Number:
  US09/982,860
• Publication Number:
  US 20020047685A1
• Time in Patent Office: 309 Days
• Field of Search: 320/119, 320/116, 320/106, 320/118, 320/122, 320/136, 320/160, 320/162, 324/434
• US Class Current: 320/119
• CPC Class Codes: B60L 58/22 Balancing the charge of battery modules
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/0016 using shunting, discharge or bypass circuits
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A method enabling balanced charging of batteries that have voltages of the same order of magnitude and which can be of different kinds uses a charger device to provide at least one constant regulation voltage appropriate to a battery, in an arrangement including a system composed of individual interfaces associated with respective rechargeable cells constituting the battery and a common interface. The individual interfaces provide the common interface with an indication relating to the voltages that they measure at the terminals of the associated cell. The common interface produces a signal controlling switching of a battery charging characteristic between two characteristics when one of the measurement circuits determining the voltage present at the terminals of the rechargeable cells reports that a maximum balancing threshold value is exceeded.

Claims

1. A method of charging an electrical battery by means of a charger device able to supply at least one appropriate constant regulation voltage to the battery to be charged, regardless of the nature of the rechargeable cells constituting said battery, provided that said battery has a nominal voltage compatible with said regulation voltage or voltages that said charger device supplies, said method including the following steps:

continuously measuring the voltage at terminals of each rechargeable cell of said battery;

activating an associated individual shunt circuit connected in parallel with each rechargeable cell as soon as the voltage measured at said terminals of said rechargeable cell exceeds a particular regulation minimum threshold value fixed as a function of the nature of said rechargeable cell and for as long as said measured voltage is above said minimum threshold value;

supplying an indication as to whether a balancing maximum threshold value fixed as a function of the nature of a rechargeable cell is exceeded or not by said voltage measured at said terminals of said rechargeable cell;

translating into the form of a single binary signal respective indications as to whether said maximum threshold is exceeded or not obtained for each of said rechargeable cells at a given time, said single signal being maintained at a first binary value for as long as none of said voltages measured at said terminals of said rechargeable cells of said battery exceeds said maximum threshold value and at a second value otherwise; and

translating said single signal obtained from said indications as to whether said maximum threshold is exceeded or not into a signal controlling switching of a battery charging characteristic between two characteristics that can be selected either directly at the charger device or via an auxiliary device associated therewith.

2. The method claimed in claim 1 wherein said charge characteristic switching control signal operates on a power switching function of said charger device or included in an auxiliary device disposed between said charger device and its power supply to enable the supply of charging current to said battery if said respective voltages measured at said terminals of said rechargeable cells are below said balancing maximum threshold value and to stop the supply of charging current to said battery as soon as the voltage measured at the terminals of one of said rechargeable battery cells exceeds said maximum threshold value.

3. The method claimed in claim 1 wherein said charge characteristic switching control signal controls the substitution of one charge regulation voltage for another in said charger device to control switching from the higher to the lower of said two regulation voltages if said voltage measured at said terminals of a rechargeable battery cell exceeds said balancing maximum threshold value and to switch from said lower to said higher regulation voltage if said respective voltages measured at said terminals of said rechargeable cells are below said balancing maximum threshold value.

4. An arrangement including a battery made up of rechargeable cells connected in series and a charger device able to provide at least one constant regulation voltage for charging said battery, which is associated with:

an individual interface for each rechargeable cell of said battery, including a first voltage measuring circuit connected to terminals of the rechargeable cell concerned to control a current shunt circuit connected in parallel with it in order to shunt at least some of the charging current that is supplied to it if said voltage measured at said terminals of said rechargeable cell exceeds a particular regulation minimum threshold value fixed as a function of the nature of said cell, said individual battery interfaces each including a second voltage measuring circuit for determining if a balancing maximum threshold value is exceeded at said terminals of the associated rechargeable cell to which said individual interface is assigned, on the basis of a voltage measured across a measuring resistor in series with said shunt device of said interface between said terminals of said associated rechargeable cell, and a circuit constituting a transmission AND logic gate which transmits a binary indication as to whether said balancing maximum threshold value is exceeded or not at said terminals of said associated rechargeable cell;

a common interface to which said individual interfaces are connected and to which each supplies at least one indication of said measured voltage for the associated rechargeable cell, said indication being used to control charging by said charger device, said common interface translating any indication relating to said balancing maximum threshold value being exceeded supplied to it by means of a transmission chain into which said transmission gates of said individual interfaces are inserted in series in the form of a charge characteristic switching control signal; and

a charger device which has at least one battery charge characteristic which is modified either in said charger device itself or in an associated auxiliary device as a function of said characteristic switching control signal.

5. The arrangement claimed in claim 4 wherein said signal indicating that a threshold value is exceeded which is supplied to said common interface via said serial transmission chain has a binary value of 1 if respective indications as to whether said threshold is exceeded or not supplied by said transmission gates of said individual interfaces reflect the fact that said voltages at said terminals of said cells of said battery by said measuring circuits of said individual interfaces are below said balancing maximum threshold value fixed for said cells constituting said battery.

6. The arrangement claimed in claim 4 wherein modifying said charge characteristic as a function of said switching control signal cuts off said charge current supplied by said charger device to said battery if an individual interface determines that the voltage at said terminals of a battery cell is above said balancing maximum threshold value fixed for each cell of said battery, said charging current being supplied if it is determined that no voltage at said terminals of a cell exceeds said threshold value.

7. The arrangement claimed in claim 4 wherein modifying the charge characteristic as a function of said switching control signal changes from one value to the other of said regulation voltage produced by said charger at the end of charging a battery, a change from said higher value to said lower value being effected if an individual interface determines that a voltage at said terminals of a battery cell exceeds said balancing maximum threshold value fixed for each cell of said battery, and the reverse change being effected if it is determined that no voltage at said terminals of one of said cells exceeds said threshold value.

8. An interface system for a battery made up of rechargeable cells, which system includes:

an individual interface for each rechargeable battery cell, each individual interface including a voltage measuring circuit connected to terminals of one of said rechargeable cells to control a current shunt circuit connected in parallel with said cell in order to shunt at least some of the charging current applied to it if the voltage measured at said terminals of said cell exceeds a particular regulation minimum threshold value fixed as a function of the nature of said cell, said individual battery interfaces each including a second voltage measuring circuit for determining if a balancing maximum threshold value is exceeded at said terminals of the associated rechargeable cell, to which said individual interface is assigned, on the basis of a voltage measured across a measuring resistor in series with said shunt device of said interface between said terminals of said associated rechargeable cell, and a circuit constituting a transmission logic AND gate which transmits a binary indication as to whether said balancing maximum threshold value is exceeded or not at said terminals of said associated rechargeable cell; and

a common interface to which said individual interfaces are connected for each to supply at least one indication relating to the voltage measured for said associated rechargeable cell, said indications being used by a charger device to control charging, said common interface translating any indication relating to said balancing maximum threshold value being exceeded, supplied to it by means of a transmission chain into which said transmission gates of said individual interfaces are inserted in series, in the form of a charge characteristic switching control signal for use by a charger device either directly or via an associated auxiliary device.