Method and apparatus for controlling the charging of a rechargeable battery to ensure that full charge is achieved without damaging the battery

An apparatus for charging a chargeable battery, said apparatus comprising:

• a connector adapted to selectively effect an electrical connection between the battery and an electrical power source;
• means for monitoring at least one characteristic parameter of a charging process during at least part of the battery charging process;
• a memory containing indicia of a plurality of reference parameters representing different desirable charging processes;
• means for comparing the monitored charging parameter with the reference parameters and for selecting, based on said comparison, one of said stored sets of reference parameters;
• and
• means for determining the time (Tmax) at which the battery terminal voltage reaches a predetermined maximum value (Vmax);
• and means for determining a remaining period of charging time in accordance with the value of Tmax.

A method of determining a process of charging a rechargeable battery having a capacity C, said method comprising:

• test charging the battery to a substantially fully charged state by supplying thereto a relatively low test charging current, the relatively low test charging current being of such a level and being supplied during such a period of time that a rise in at least one charging parameter, comprising battery temperature, inner pressure of the battery and the charging voltage of the batteries and/or the cells thereof, is obtained during the test charging;
• and
• determining a maximum value for the charging parameter during the test charging;
• and
• carrying out subsequent charging of the battery at a higher rate controlled to avoid exceeding the determined maximum value for the charging parameter.

A method of charging a rechargeable battery having a pair of terminals, said method comprising:

• connecting the terminals of the battery to an electrical power source;
• initially test charging the battery by supplying a first test charging current to the terminals of the battery for a first period of time;
• monitoring at least one test parameter;
• subsequently test discharging the battery for a second period of time;
• monitoring at least one test discharging parameter;
• selecting values of at least one characteristic charging parameter based on the monitoring of the test charging and discharging processes;
• subsequently at least partly charging the battery, wherein the battery charging process is controlled so that it is substantially in accordance with the values selected for the characteristic charging parameter, and terminating the charging process at the expiration of a remaining period of charging time determined when the battery terminal voltage has reached a predetermined maximum voltage.

An apparatus for charging a rechargeable battery, said apparatus comprising:

• a connector disposed to selectively effect an electrical connection between the battery and an electrical power source;
• means for initially test charging the battery by supplying a first test charging current to terminals of the battery for a first period of time;
• means for monitoring at least one test charging parameter;
• means for test discharging the battery for a, second period of time;
• means for monitoring at least one test discharging parameter;
• means for selecting a sequence of at least one charging parameter based on the monitoring of the test charging and discharging processes;
• and
• means for controlling the process of partly charging the battery substantially in accordance with the sequence selected for the charging parameter, determining a remaining period of charging time when the value of the battery terminal voltage has reached a predetermined maximum voltage, and terminating the charging process when the remaining period of time has expired.

A method of charging a rechargeable battery having terminals and a C-rate based on a predetermined capacity value of the rechargeable battery, said method comprising:

• connecting an electrical power source to the terminals;
• charging the battery with a substantially constant charging current during part of the charging process, said substantially constant charging current being several times the C-rate of the battery;
• monitoring the voltage of the terminals;
• controlling the charging process such that when a maximum terminal voltage has been reached, the battery voltage is maintained substantially constant for the remaining period of the charging process;
• determining, at the time when the maximum terminal voltage has been reached, the remaining charging period of the charging process in accordance with the time when the maximum terminal voltage has been reached;
• and
• stopping the charging process at the end of the remaining charging period.

A method of charging a rechargeable battery, comprising:

• storing indicia of charging periods corresponding to values of a predetermined charging parameter of the battery;
• applying electrical energy to the battery;
• sampling the parameter;
• and
• terminating application of electrical energy to the battery in accordance with the charging periods corresponding to the sampled values of the predetermined charging parameter.

A method of charging a rechargeable battery, comprising:

• storing indicia of a respective charging time period corresponding to each of a plurality of values of at least one characteristic parameter of the charging process during at least a predetermined part of the charging process;
• applying electrical energy to the battery;
• determining the value of the characteristic parameter for at least one point in the predetermined part of the charging process;
• and
• terminating application of electrical energy to the battery in accordance with the charging time period corresponding to the value of the characteristic parameter.

A method of charging a rechargeable battery, comprising:

• storing reference values for at least one characteristic parameter of the charging process during at least part of the process of charging at least one type of battery;
• connecting a source of electrical energy to the battery;
• monitoring the value of at least the one characteristic parameter of the charging process during at least part of the process of charging the battery,
• comparing the values of the charging parameter monitored with the stored corresponding reference values, and
• determining the remaining period necessary to charge the battery based upon the stored reference values.

A method of charging a rechargeable battery, comprising:

• storing indicia of a respective period of time necessary to complete charging corresponding to each of a plurality of values of at least one characteristic parameter of the charging process;
• controllably applying a current of a first predetermined value to the battery;
• monitoring the battery voltage;
• controllably applying a current of a second predetermined value, less than the first predetermined value to the battery in accordance with the battery voltage reaching a first predetermined value;
• during a period in accordance with the battery voltage reaching a second predetermined value, determining the value of the one characteristic parameter;
• and
• terminating the charging in accordance with the time period corresponding to the value of the characteristic parameter.

An apparatus for charging a rechargeable battery, said apparatus comprising:

• an electrical power supply circuit;
• a measuring device for generating indicia of the value of at least one characteristic parameter of the charging process at sequential points of time during charging;
• a storage circuit for storing indicia of measured parameter values, calculated parameter values and reference values;
• a control unit, cooperating with the power supply circuit and the storage circuit, for determining a possible stop point of time for the charging process at least some of the measurement points of time, the stop point time being determined in accordance with a comparison of the measured characteristic parameter with the reference values, and to determine an optimum remaining charging time and thereby an optimum stop point of time from a plurality of possible stop points of time resulting from such comparisons, each comparison being based on a correlation between parameter values at subsequent points of time and their distances in time from their respective possible stop point of time.

A method of charging a rechargeable battery having a pair of terminals, said method comprising

• connecting an electrical power source to the terminals of the battery,
• monitoring at least one charging parameter during at least part of the process of charging of the battery,
• comparing a sequence of values of said at least one charging parameter with stored reference parameter sequences representing idealistic or desirable processes of charging the battery for different starting states of charge of the battery,
• selecting the reference sequence corresponding to the sequence of values of said at least one charging parameter, and
• controlling the process of charging the battery so as to cause the sequence of subsequent values of said at least one parameter to approximate the selected reference parameter sequence.

An apparatus for charging a rechargeable battery, said apparatus comprising:

• connecting means for connecting the battery to an electrical power source,
• means for monitoring at least one charging parameter during at least part of the process of charging the battery,
• storing means for storing a plurality of reference parameter sequences representing idealistic or desirable processes of charging the battery for various starting states of charge of the battery,
• means for comparing the sequence of values of said at least one charging parameter with the stored reference parameter sequences and for selecting the reference course corresponding to the sequence of values of said at least one charging parameter, and
• means for controlling the process of charging the battery so as to cause the sequence of subsequent values of said at least one parameter to the selected reference parameter sequence.