Method for controlling battery pack
View Patent ↗A method controls a battery pack that includes a rechargeable battery, a control circuit that controls charge operation of the battery, and a charge control element that controls the charge current through the control circuit. In the method, even though the control circuit controls the charge control element so that the charge control element turns to OFF, in a case where the charge current is detected, the control circuit determines that abnormality occurs if detecting that the current flows at a rate not less than a first current value during a first detection period, and additionally determines that abnormality occurs if detecting a state the current flows at a rate less than the first current value for a second detection period longer than the first detection period.
1. A method for controlling a charge current of a battery pack comprising a rechargeable battery, a control circuit that controls a charge operation of the rechargeable battery, and a charge control element controlled by the control circuit so as to control the charge current, the method comprising:
controlling the charge control element with the control circuit so that the charge control element is turned ON in the charge operation;
detecting the charge current of the rechargeable battery in the charge operation and measuring a detection time using the control circuit;
controlling the charge control element with the control circuit so that the charge control element turns OFF, if the control circuit determines that an abnormality occurs based on the charge current and the detection time; and
while the charge control element is OFF, stopping a charge current supply, when the control circuit determines that a non-charge abnormality has occurred, wherein
(i) the control circuit determines that the non-charge abnormality has occurred when the charge current detected is greater than or equal to a first predetermined current value for a first predetermined time period, and
(ii) the control circuit determines that the non-charge abnormality has occurred when the charge current detected is less than the first predetermined current value and not less than a second predetermined current value for a second predetermined time period longer than the first predetermined time period.
2. The method according to claim 1 , wherein while the charge control element is OFF, the control circuit repeats a determination of whether the charge current is greater than or equal to the first predetermined current value for the first predetermined time period, and whether the charge current is less than the first predetermined current value and not less than the second predetermined current value for the second predetermined time period that is longer than the first predetermined time period, at a constant cycle period, and thus determines if the non-charge abnormality occurs.
3. The method according to claim 1 , wherein the first predetermined current value is 100 mA, and the first predetermined time period is 20 sec.
4. The method according to claim 1 , wherein the second predetermined current value is 20 mA, and the second predetermined time period is 90 sec.
5. The method according to claim 1 , wherein the second predetermined current value is not less than 1 mA.
6. The method according to claim 1 , wherein the rechargeable battery is a nickel-hydrogen battery.
7. The method according to claim 1 , wherein the rechargeable battery is a lithium-ion rechargeable battery.
8. The method according to claim 1 , wherein a switching transistor is used as the charge control element.
9. The method according to claim 1 , wherein the control circuit provides an OFF signal to the charge control element and thus controls the charge control element so that the charge control element turns to OFF.
10. The method according to claim 1 , further comprising:
controlling the charge control element with the control unit so that the charge control element is turned to OFF if at least one of a full-charge state, an abnormal current, an abnormal temperature, or an abnormal voltage is detected.
11. The method according to claim 10 , further comprising:
controlling the charge control element with the control circuit so that the charge control element turns to OFF if a voltage drop −ΔV relative to the peak voltage of battery voltage is detected, thus determining that the battery is in the full-charge state, wherein the rechargeable battery is a nickel hydrogen battery.
12. The method according to claim 10 , further comprising:
controlling the charge control element so that the charge control element turns to OFF if a battery voltage is not less than a preset value and the charge current is not more than a preset value is detected, thus determining that the battery is in the full-charge state, wherein the rechargeable battery is a lithium-ion rechargeable battery.
13. The method according to claim 1 , wherein the control circuit communicates with an external device through a communication processing portion if an abnormality of the battery is detected.