BATTERY CAPACITY MEASUREMENT
In one embodiment, a method can be used for measuring an effective capacity of a battery. A first measurement is performed during a phenomenon of relaxation of the battery. The first measurement measures a first voltage delivered by the in-use battery from a duration. The duration is the difference between a first initial time and a second time that is defined as the time when a first line reaches a second voltage delivered by the battery when the battery is relaxed, the first line being tangent to the origin of a curve corresponding to the evolution over time of a voltage delivered by the battery during the phenomenon of relaxation.
1 . A method of measuring an effective capacity of a battery, the method comprising:
performing a first measurement during a phenomenon of relaxation of the battery, the first measurement measuring a first voltage delivered by the battery when in use from a duration,
wherein the duration is the difference between a first initial time and a second time that is defined as the time when a first line reaches a second voltage delivered by the battery when the battery is relaxed, the first line being tangent to the origin of a curve corresponding to the evolution over time of a voltage delivered by the battery during the phenomenon of relaxation.
2 . The method according to claim 1 , wherein the phenomenon of relaxation of the battery is obtained by performing a partial charge of the battery until the battery requires an end-of-charge current, the phenomenon of relaxation appearing when the partial charge is interrupted.
3 . The method according to claim 2 , wherein the partial charge is performed at constant current and at constant voltage.
4 . The method according to claim 2 , wherein the value of the end-of-charge current is defined as being equal to the typical capacity of the battery divided by 10 hours.
5 . The method according to claim 3 , wherein the effective capacity is given by the following formula:
Ceff
=
Ctyp
-
R
(
Vr
-
V
(
tr
)
)
where:
Ceff is the effective capacity;
Ctyp represents the typical capacity of the battery;
R represents the resistance of the battery;
Vr represents the voltage delivered by the battery when the battery is relaxed; and
V(tr) represents the first voltage.
6 . The method according to claim 1 , further comprising performing a second measurement of a resistance of the battery.
7 . The method according to claim 6 , wherein performing the second measurement comprises performing a second discharge of the battery with a first current.
8 . The method according to claim 7 , wherein the first current is greater than 500 mA.
9 . The method according to claim 8 , wherein the phenomenon of relaxation of the battery is obtained by performing a partial charge of the battery until the battery requires an end-of-charge current, the phenomenon of relaxation appearing when the partial charge is interrupted, and wherein the first discharge is the second discharge.
10 . The method according to claim 9 , wherein the battery is a Lithium Ferro-Phosphate type battery.
11 . The method according to claim 1 , wherein the battery is a battery of an electronic cigarette.
12 . A method for measuring the aging of a battery, the method comprising:
performing a first measurement during a phenomenon of relaxation of the battery, the first measurement measuring a first voltage delivered by the battery when in use from a duration; and
determining the aging of the battery as a function of the first measurement;
wherein the duration is the difference between a first initial time and a second time that is defined as the time when a first line reaches a second voltage delivered by the battery when the battery is relaxed, the first line being tangent to the origin of a curve corresponding to the evolution over time of a voltage delivered by the battery during the phenomenon of relaxation.
13 . The method according to claim 12 , wherein determining the aging of the battery comprises finding a ratio of the effective capacity of the battery to the typical capacity of the battery.
14 . The method according to claim 12 , wherein the battery is a battery of an electronic cigarette.
15 . A method of measuring an effective capacity of a battery, the method comprising:
performing a first measurement during a phenomenon of relaxation of the battery, the first measurement measuring a first voltage delivered by the battery when in use from a duration; and
performing a second measurement of a resistance of the battery when performing a second discharge of the battery with a first current;
wherein the duration is the difference between a first initial time and a second time that is defined as the time when a first line reaches a second voltage delivered by the battery when the battery is relaxed, the first line being tangent to the origin of a curve corresponding to the evolution over time of a voltage delivered by the battery during the phenomenon of relaxation; and
wherein the phenomenon of relaxation of the battery is obtained by performing a partial charge of the battery until the battery requires an end-of-charge current, the phenomenon of relaxation appearing when the partial charge is interrupted.
16 . The method according to claim 15 , wherein the partial charge is performed at constant current and at constant voltage.
17 . The method according to claim 15 , wherein the value of the end-of-charge current is defined as being equal to the typical capacity of the battery divided by 10 hours.
18 . The method according to claim 15 , wherein the first current is greater than 500 mA.
19 . The method according to claim 18 , wherein the phenomenon of relaxation of the battery is obtained by performing the partial charge of the battery until the battery requires the end-of-charge current, the phenomenon of relaxation appearing when the partial charge is interrupted, and wherein the first discharge is the second discharge.
20 . The method according to claim 19 , wherein the battery is a Lithium Ferro-Phosphate type battery.