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1. WO2017129259 - CONTROL DEVICE AND METHOD FOR DISCHARGING A RECHARGEABLE BATTERY

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CLAIMS

1. A control device (6) for controlling discharging of a rechargeable battery (2),

the control device (6) being configured to:

determine the voltage (Vx) of the battery (2) during discharging of the battery (2),

stop discharging, when the determined voltage (Vx) falls below a first predetermined lower voltage limit (Vmini),

determine the voltage (Vx) of the battery (2) after stopping discharging,

determine the voltage difference (AVX) between the first predetermined lower voltage limit (Vmini) and the determined voltage of the battery (2) after stopping discharging, and

continue discharging, when the determined voltage difference (AVX) exceeds a predetermined threshold (AVT).

2. The control device (6) according to claim 1, further configured to:

when the determined voltage difference exceeds the predetermined threshold,

replace the first predetermined lower voltage limit (Vmini) by a second predetermined lower voltage limit (Vmjn2) being smaller than the first predetermined lower voltage limit (Vmjni) and restart discharging of the battery (2),

determine the voltage (Vx) of the battery (2) during discharging of the battery (2), and,

when the voltage falls below the second predetermined lower voltage limit (Vmin2) or the lower limit of a predetermined allowed state of charge (SOC) range of the battery (2) is reached,

determine that the battery (2) is fully discharged and reset the predetermined threshold (AVT).

3. The control device (6) according to any one of the preceding claims, further configured to:

when the determined voltage difference (AVX) does not exceed the predetermined threshold (AVT),

determine that the battery (2) is fully discharged and reset the predetermined threshold (AVT).

4. The control device (6) according to any one of the preceding claims, further configured to determine the threshold (AVT) based on the state of charge (SOC) of the battery (2) before starting discharging.

5. The control device (6) according to any one of the preceding claims, further configured to determine the threshold (AVT) based on a determined degradation (ax) of the battery (2).

6. The control device (6) according to claim 5, further configured to determine the degradation (ax) of the battery (2) based on a temperature / frequency distribution of the battery (2) and a predetermined degradation rate (β) of the battery (2).

7. The control device (6) according to any one of the preceding claims 5 to 6, wherein

the determination of the degradation (ax) of the battery (2) is based on the Arrhenius equation.

8. The control device (6) according to any one of the preceding claims 6 to 7, further configured to determine the temperature / frequency distribution of the battery (2) based on recording for each temperature of the battery (2) how much time the battery (2) had this temperature during its lifetime.

9. The control device (6) according to any one of the preceding claims, comprising a voltage sensor (10) for determining the voltage (Vx) of the battery (2).

10. The control device (6) according to any one of the preceding claims, comprising a temperature sensor (8) for determining the temperature (T) of the battery (2).

11. A battery (2) pack comprising:

at least one battery (2), in particular a solid state bipolar battery, and

a control device (6) according to any one of the preceding claims.

12. A battery discharging system comprising:

at least one battery (2), in particular a solid state bipolar battery, a discharging device (5) for the battery (2), and

a control device (6) according to any one of claims 1 to 10.

13. A vehicle (1) comprising:

an electric motor (4), and

a battery pack according to claim 11.

14. A vehicle (1) comprising:

an electric motor (4),

at least one battery (2), in particular a solid state bipolar battery, and

a control device (6) according to any one of claims 1 to 10.

15. A method of controlling discharging of a rechargeable battery (2), comprising the steps of:

determining the voltage (Vx) of the battery during discharging of the battery,

stopping discharging, when the determined voltage (Vx) falls below a first predetermined lower voltage limit (Vmax),

determining the voltage (Vx) of the battery after stopping discharging,

determining the voltage difference (AVX) between the first predetermined lower voltage limit (Vmini) and the determined voltage of the battery (2) after stopping discharging, and

continuing discharging, when the determined voltage difference (AVX) exceeds a predetermined threshold (AVT).

16. The method according to claim 15, further comprising the steps of:

when the determined voltage difference exceeds the predetermined threshold,

replacing the first predetermined lower voltage limit (Vmini) by a second predetermined lower voltage limit (Vmin2) being smaller than the first predetermined lower voltage limit (Vmini) and restarting discharging of the battery (2),

determining the voltage (Vx) of the battery (2) during discharging of the battery (2), and,

when the voltage falls below the second predetermined lower voltage limit (Vmin2) or the lower limit of a predetermined allowed state of charge (SOC) range of the battery (2) is reached,

determining that the battery (2) is fully discharged and resetting the predetermined threshold (AVT).

17. The method according to claim 15 or 16, further comprising the steps of:

when the determined voltage difference (AVX) does not exceed the predetermined threshold (AVT),

determining that the battery (2) is fully discharged and resetting the predetermined threshold (AVT).

18. The method according to any one of the preceding claims 15 to 17, wherein the threshold (Δν ) is determined based on the state of charge (SOC) of the battery (2) before starting discharging.

19. The method according to any one of the preceding claims 15 to 18, wherein the threshold (AVT) is determined based on a determined degradation (ax) of the battery (2).

20. The method according to claim 19, wherein the degradation (ax) of the battery (2) is determined based on a temperature / frequency distribution of the battery (2) and a predetermined degradation rate (β) of the battery (2).

21. The method according to any one of the preceding claims 19 to 20, wherein the determination of the degradation (ax) of the battery (2) is based on the Arrhenius equation.

22. The method according to any one of the preceding claims 20 to 21, wherein the temperature / frequency distribution of the battery (2) is determined based on recording for each temperature of the battery (2) how much time the battery (2) had this temperature during its lifetime.