Method and circuitry to adaptively charge a battery/cell using the state of health thereof
The present inventions, in one aspect, are directed to techniques and/or circuitry to determining data which is representative of the state of health, or a change therein, of the battery using the data which is representative of (i) the relaxation time of the battery and/or (ii) the overpotential of the battery. In another aspect the present inventions are directed to techniques and/or circuitry to adapt one or more characteristics of a charge signal using data which is representative of the state of health, or a change therein, of the battery. In yet another aspect the present inventions are directed to techniques and/or circuitry to determine a state of charge of the battery using data which is representative of the state of health, or a change therein, of the battery.
1. A method to determine a state of health of a battery and charge the battery via charging circuitry, wherein the battery includes at least two terminals, the method comprising:
(a) applying a signal to at least two terminals of the battery, wherein the signal injects charge into the battery;
(b) measuring a terminal voltage between terminals of the battery at a predetermined time relative to applying to the signal;
(c) from the measurements of the terminal voltage in (b), determining a state of health of the battery or a change therein, wherein the state of health is representative of degradation of the battery and/or an ability of the battery to hold a charge; and
(d) adapting one or more characteristics of a charging process for the battery, using the determined state of health of the battery, or a change therein.
2. The method of claim 1 , wherein:
the signal includes a plurality of charge packets, wherein each charge packet includes at least one pulse, and
adapting one or more characteristics of the charging process includes changing (i) an amount of time between pulses of temporally successive charge packets of the plurality of charge packets and/or (ii) an amplitude and/or duration of the at least one pulse of a charge packet of the plurality of charge packets.
3. The method of claim 1 , wherein:
the charging process includes supplying a plurality of charge packets to the battery terminals, wherein each charge packet includes at least one charge pulse and at least one discharge pulse, and
adapting one or more characteristics of the signal further includes adapting an amplitude and/or pulse width of at least one charge pulse and/or at least one discharge pulse of at least one charge packet.
4. The method of claim 1 , further comprising determining a state of charge of the battery using data which is representative of the state of health, or a change therein, of the battery.
5. The method of claim 4 , further comprising:
correlating the data which is representative of the state of health, or a change therein, to a first relationship between an open circuit voltage and an amount of charge in the battery;
calculating an open circuit voltage of the battery using a terminal voltage of the battery, a current applied to or removed from the battery, and an impedance of the battery; and
determining the state of charge of the battery using (i) the calculated open circuit voltage and (ii) the first relationship of the open circuit voltage to the amount of charge in the battery.
6. The method of claim 1 , further comprising determining the equilibrium voltage of the battery using characteristics of a decay of the terminal voltage associated with the battery.
7. The method of claim 1 , further comprising using the measured terminal voltages to calculate information representing an overpotential of the battery, a relaxation time of the battery, and/or a partial relaxation time of the battery.
8. The method of claim 7 , wherein the relaxation time is an amount of time corresponding to when, in response to a pulse of the signal, the terminal voltage of the battery decays to at least a predetermined voltage.
9. The method of claim 8 , wherein the predetermined voltage is a voltage which is constant or substantially constant after applying the pulse of the signal and before applying another and immediately subsequent pulse of the signal.
10. The method of claim 8 , wherein the predetermined voltage is a voltage at which the relaxation time is capable of being determined using a form, shape and/or rate of decay of the voltage at the terminals of the battery due to the pulse of the signal.
11. The method of claim 1 , wherein measuring the terminal voltage comprises:
(i) measuring a first terminal voltage of the battery at a first predetermined time relative to applying the signal to the terminals of the battery; and
(ii) monitoring the terminal voltage of the battery after applying the signal to the terminals of the battery to determine a second terminal voltage, wherein the second terminal voltage of the battery is a voltage which correlates to an equilibrium voltage of the battery.
12. The method of claim 11 , further comprising calculating data representative of an overpotential of the battery using the first terminal voltage of the battery and the second terminal voltage of the battery,
wherein determining the state of health of the battery or a change therein uses the data which is representative of the overpotential of the battery.
13. The method of claim 12 , wherein calculating data which is representative of the overpotential of the battery further comprises using
(i) characteristics of a decay of the terminal voltage of the battery, and
(ii) an amount of time for the terminal voltage of the battery to decay to the second terminal voltage of the battery.
14. An apparatus to charge a battery including at least two terminals, the apparatus comprising:
charging circuitry, coupled to the battery, to:
generate a signal, and
apply the signal to the battery;
monitoring circuitry, coupled to the battery, to measure a voltage at the terminals of the battery; and
control circuitry, coupled to the charging circuitry and the monitoring circuitry, and configured to:
(a) apply the signal to at least two terminals of the battery, wherein the signal injects charge into the battery;
(b) measure a terminal voltage between terminals of the battery at a predetermined time relative to applying to the signal;
(c) from the measurements of the terminal voltage in (b), determine a state of health of the battery or a change therein, wherein the state of health is representative of degradation of the battery and/or an ability of the battery to hold a charge; and
(d) adapting one or more characteristics of a charging process for the battery based on the determined state of health of the battery, or a change therein.
15. The apparatus of claim 14 , wherein:
the signal includes a plurality of charge packets, wherein each charge packet includes at least one pulse, and
the control circuitry is configured to adapt one or more characteristics of the charging process by changing (i) an amount of time between pulses of temporally successive charge packets of the plurality of charge packets and/or (ii) an amplitude and/or duration of the at least one pulse of a charge packet of the plurality of charge packets.
16. The apparatus of claim 14 , wherein:
the signal includes a plurality of charge packets, wherein each charge packet includes at least one charge pulse and at least one discharge pulse, and
the control circuitry is configured to adapt one or more characteristics of the charging process by adapting an amplitude and/or pulse width of at least one charge pulse and/or at least one discharge pulse of at least one charge packet.
17. The apparatus of claim 14 , wherein the control circuitry is further configured to determine a state of charge of the battery using data which is representative of the state of health, or a change therein, of the battery.
18. The apparatus of claim 17 , wherein the control circuitry is further configured to:
correlate the data which is representative of the state of health, or a change therein, to a first relationship between an open circuit voltage and an amount of charge in the battery;
calculate an open circuit voltage of the battery using a terminal voltage of the battery, a current applied to or removed from the battery, and an impedance of the battery; and
determine the state of charge of the battery using (i) the calculated open circuit voltage and (ii) the first relationship of the open circuit voltage to the amount of charge in the battery.
19. The apparatus of claim 14 , wherein the control circuitry is further configured to determine the equilibrium voltage of the battery using characteristics of a decay of the terminal voltage associated with the battery.
20. The apparatus of claim 14 , wherein the control circuitry is further configured to use the measured terminal voltages to calculate information representing an overpotential of the battery, a relaxation time of the battery, and/or a partial relaxation time of the battery.
21. The apparatus of claim 20 , wherein the relaxation time is an amount of time corresponding to when, in response to a pulse of the signal, the terminal voltage of the battery decays to at least a predetermined voltage.
22. The apparatus of claim 21 , wherein the predetermined voltage is a voltage which is constant or substantially constant after applying the pulse of the signal and before applying another and immediately subsequent pulse of the signal.
23. The apparatus of claim 21 , wherein the predetermined voltage is a voltage at which the relaxation time is capable of being determined using a form, shape and/or rate of decay of the voltage at the terminals of the battery due to the pulse of the signal.
24. The apparatus of claim 14 , wherein the monitoring circuitry is configured to:
(i) measure a first terminal voltage of the battery at a first predetermined time relative to applying the signal to the terminals of the battery; and
(ii) monitor the terminal voltage of the battery after applying the signal to the terminals of the battery to determine a second terminal voltage, wherein the second terminal voltage of the battery is a voltage which correlates to an equilibrium voltage of the battery.
25. The apparatus of claim 24 , wherein the control circuitry is further configured to
calculate data representative of an overpotential of the battery using the first terminal voltage of the battery and the second terminal voltage of the battery,
determine the state of health of the battery or a change therein by using the data which is representative of the overpotential of the battery.
26. The apparatus of claim 25 , wherein the control circuitry is further configured to calculate the data which is representative of the overpotential of the battery by using
(i) characteristics of a decay of the terminal voltage of the battery, and
(ii) an amount of time for the terminal voltage of the battery to decay to the second terminal voltage of the battery.