Method for charging a battery and battery thus charged

Patent metadata

Field	Value
Publication number	US-9768629-B2
Application number	US-201314413539-A
Country	US
Kind code	B2
Filing date	Jul 2, 2013
Priority date	Jul 10, 2012
Publication date	Sep 19, 2017
Grant date	Sep 19, 2017

Abstract

The invention relates to a method for charging a battery comprising rechargeable cells. According to the invention, to perform the ith charge of the battery, where i≧2, connection of the charging terminals to the charger is detected triggering connection of the cells to their bypass circuit during a pre-emptive bypass time (TP ji ). Next, for each cell, during a second phase (C ji ), the bypass circuit is disconnected from the cell until the voltage of the cell reaches a preset voltage, the pre-emptive bypass time (TP ji ) for the ith charge having been calculated as a function of the total connection time, during at least one preceding charge, of the bypass circuit associated with this cell, until all the cells have reached the preset voltage. At least one length of time allowing the first time (TP ji ) for the ith charge and/or said total connection time to be determined was memorized in a memory of the battery during this at least one preceding charge.

First claim

The invention claimed is:

1. A method for charging a battery having respective cells,
wherein the method comprises, to perform an i th charging of the battery with i greater than or equal to two,
memorizing in a memory of the battery during at least one charging previous to the i th charging at least one respective time period associated with each respective cell and representative of a respective first pre-emptive bypass time of a respective bypass circuit to the respective cell for the i th charging and/or of a respective total connection time of the respective bypass circuit to the respective cell for the at least one charging previous to the i th charging until all the respective cells reached a pre-set voltage, which is prescribed for the respective cell and is nonzero,
calculating the respective first pre-emptive bypass times associated with the respective cells for the i th charging, based on the at least one respective time period,
detecting connection of charging terminals of the battery to a charger for the i th charging, to trigger
at a respective first phase, connection of the respective cells to their respective bypass circuit for the respective first pre-emptive bypass time;
next, for each respective cell, once the respective first pre-emptive bypass time has elapsed, disconnecting at a respective second phase the respective bypass circuit from the respective cell until a voltage of the respective cell reaches the pre-set voltage.

2. The method according to claim 1 , further comprising for at least one of the respective cells and for the i th charging, at the end of the respective second phase, the respective bypass circuit to the respective cell so that the voltage of the respective cell does not exceed a threshold charge voltage during a respective charge maintaining third phase and at least until the voltages of the respective cells have all reached the pre-set voltage.

3. The method according to claim 2 , further comprising measuring a respective third connection time of the respective bypass circuit to the respective cell during the respective charge maintaining third phase,
wherein said calculating of the respective first pre-emptive bypass time associated with the respective cell for the i th charging at least takes into account a respective first connection time of the respective bypass circuit to the respective cell during the respective first phase of the at least one charging previous to the i th charging and the respective third connection time during the respective charge maintaining third phase of the at least one charging previous to the i th charging.

4. The method according claim 3 , further comprising measuring the voltage of the respective cell and comparing the voltage of the respective cell with the pre-set voltage, wherein the respective third connection time corresponds to the voltage of the respective cell having reached the pre-set voltage.

5. The method according to claim 4 , wherein the respective third connection time ends at an instant from which all the cells respective have reached the pre-set voltage.

6. The method according to claim 1 , wherein the calculating of the respective first pre-emptive bypass time is done as a function of the respective total connection time, during an i−1 th charging, of the respective bypass circuit to the respective cell until all the respective cells reached the pre-set voltage.

7. The method according to claim 1 , wherein the memorizing of the at least one time period is done during an i−1 th charging.

8. The method according to claim 1 , wherein the memorizing comprises memorizing of the respective first pre-emptive bypass time of the respective bypass circuit associated with the respective cell for the i th charging.

9. The method according to claim 1 , wherein the memorizing comprises memorizing of the respective total connection time of the respective bypass circuit to the respective cell for the at least one charging previous to the i th charging.

10. The method according to claim 9 , wherein:
the calculating of the respective first pre-emptive bypass time TP ij associated with the respective cell j for the i th charging is done as follows:
TP ij =TP ji−1 +M ji−1 −min j ( TP ji−1 +M ji−1 )

where min j (TP ji−1 +M ji−1 ) designates the minimum of TP ji−1 +M ji−1 on the respective cells j.

11. The method according to claim 9 , wherein the calculating of
the respective first pre-emptive bypass time TP ji associated with the respective cell j for the i th charging is done as follows:
TP ji =a ·( TP ji−1 +M ji−1 )− b ·min j ( TP ji−1 +M ji−1 )

where min j (TP ji−1 +M ji−1 ) designates the minimum of TP ji−1 +M ji−1 on the respective cells, and where a, b are prescribed nonzero coefficients.

12. The method according to claim 11 , further comprising determining the prescribed nonzero coefficients a and b as a function of a charge level of the battery when detecting the connection of the charge terminals to the charger.

13. The method according to claim 1 , further comprising for the first charging of each respective cell of the battery:
detecting connection of the charging terminals to the charger,
to trigger, during a respective fourth phase, the disconnection of each respective cell from its respective bypass circuit to charge the respective cell until the voltage of the respective cell reaches the pre-set voltage;
then connecting, for at least one of the respective cells, at the end of the respective fourth phase, the respective bypass circuit to the respective cell for a respective third connection time so that the voltage of the respective cell does not exceed a threshold charge voltage during a respective charge maintaining third phase until the voltages of the respective cells have all reached the pre-set voltage,
wherein the respective first pre-emptive bypass time respectively associated with the respective cell, and valid for at least a second charging, corresponds to the respective third connection time of the respective bypass circuit to the respective cell during the respective charge maintaining third phase of the first charging.

14. The method according to claim 2 , wherein the pre-set voltage is a voltage lower than or equal to the threshold charge voltage which is prescribed for the respective charge maintaining cell and which is nonzero.

15. A battery comprising respective cells, which are rechargeable, terminals for charging the respective cells and able to be connected to a charger, respective bypass circuits associated with the respective cells, switching elements allowing each respective cell to be connected and disconnected to and from its respective bypass circuit, control means to control the switching elements, means for measuring a voltage of each respective cell,
wherein the control means comprise:
means to measure a respective total connection time, during which the respective bypass circuit is connected to the respective cell until all the cells reached a pre-set voltage, which is prescribed for the respective cell and is nonzero,
means to compute for each respective cell a respective first pre-emptive bypass time respectively associated with the respective cell for the i th charging where i≧2 as a function of the respective total connection time of at least one charging of the respective cell previous to the i th charging;
at least one memory to memorize at least one time period associated with the respective cell and representative of the respective first pre-emptive bypass time and/or of the respective total connection time;
a

Assignees

• Blue Solutions

Inventors

• Jestin Jean-Jacques
• Hingant Dominique

Classifications

• H02J7/54 Primary

  Passive balancing, e.g. using resistors or parallel MOSFETs · CPC title

• H02J7/00 Primary

  Circuit arrangements for charging or discharging batteries or for supplying loads from batteries · CPC title

• H01M10/441

  for several batteries or cells simultaneously or sequentially · CPC title

• H01M2010/4271

  Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing · CPC title

• H01M10/4257

  Smart batteries, e.g. electronic circuits inside the housing of the cells or batteries · CPC title