Method for managing charging of a rechargeable battery

• US 8,093,866 B2
• Filed: 11/05/2007
• Issued: 01/10/2012
• Est. Priority Date: 11/06/2006
• Status: Expired due to Fees

• Current Assignee: Commissariat a L'Energie Atomique (French Alternative Energies and Atomic Energy Commission)
• Original Assignee: Commissariat a L'Energie Atomique (French Alternative Energies and Atomic Energy Commission)
• Inventors: Karoui, Fathia, Lemaire, Elisabeth, Lefrou, Christine
• Primary Examiner(s): WILLIAMS, ARUN C
• Application Number:
  US12/312,027
• Publication Number:
  US 20100060240A1
• Time in Patent Office: 1,527 Days
• Field of Search: 320/145
• US Class Current: 320/145
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H02J 7/00711 with introduction of pulses during the charging process
• CPC Class Codes: H02J 7/007184 in response to battery voltage gradient
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

The management method comprises a charging phase and may comprise an optional prior phase of estimating the state of charge of the battery. Comparison of the absolute value of the slope of the voltage at the battery terminals with a full-charge threshold at the end of each period, when a pulsed current is applied, is used as end-of-charging criterion in the charging phase and/or as full-charge criterion in the phase of estimating the state of charge. The charging phase by pulsed current is interrupted when the slope reaches the full-charge threshold. This same comparison constitutes the criterion for estimating the necessity for going to a charging step after the prior phase of estimating the state of charge of the battery.

Claims

1. A method for managing charging of a rechargeable battery, comprising at least one charging phase comprising at least:

charging said battery by periodic rectangular current pulses alternately taking a first amplitude during a first period and a second amplitude during a second period, the second amplitude being lower than the first,

measuring periodically the voltage at the battery terminals,

calculating, from said measured voltage, a slope value representative of the voltage variation versus time,

comparing an absolute value of the slope at the end of each period with a predetermined full-charge threshold representative of full charge of the battery,

and interrupting said charging by periodic rectangular current pulses when said absolute value of the slope is greater than or equal to said full-charge threshold.

2. The method according to claim 1, wherein the full-charge threshold is equal to 300mV/s.

3. The method according to claim 1, wherein said charging phase comprises before charging by periodic rectangular current pulses,

charging said battery at a constant current,

measuring periodically a voltage at the battery terminals,

calculating, from said measured voltage, a slope value representative of the voltage variation versus time,

comparing an absolute value of the slope with a predetermined range,

and switching to charging by periodic rectangular current pulses when the absolute value of the slope enters said predetermined range.

4. The method according to claim 3, wherein the predetermined range is comprised between 1mV/s and 6mV/s.

5. The method according to claim 1, comprising before the charging phase, a prior phase of estimating the state of charge of the battery, said prior phase of estimating the state of charge comprising:

applying a few periodic rectangular test current pulses alternately taking the first amplitude during the first period and the second amplitude during the second period,

measuring periodically the voltage at the battery terminals,

calculating, from said measured voltage, the voltage slope value,

comparing the absolute value of the slope at the end of each period with said full-charge threshold,

and switching to charging phase when said absolute value of the slope (P) is lower than said full-charge threshold.

6. A method for managing charging of a rechargeable battery, comprising at least one charging phase and a prior phase of estimating the state of charge of the battery, said prior phase of estimating the state of charge comprising:

applying a few periodic rectangular test current pulses alternately taking the first amplitude during the first period and the second amplitude during the second period,

measuring periodically a voltage at the battery terminals,

calculating, from said measured voltage, a voltage slope value representative of the variation of the voltage versus time,

comparing the absolute value of the slope at the end of each period with a predetermined full-charge threshold,

and switching to charging phase when said absolute value of the slope is lower than said full-charge threshold.