Method and device for estimating power limit of battery pack, and battery management system

1. A method for estimating a power limit of a battery pack, comprising:

obtaining an actual minimum cell voltage of an electrical core with a minimum voltage in the battery pack;

obtaining a static discharge power limit of the battery pack;

calculating, based on the actual minimum cell voltage, an estimated discharge voltage of the electrical core with the minimum voltage for use when the battery pack is discharged based on the static discharge power limit;

determining whether the estimated discharge voltage falls between a discharge voltage control threshold of the electrical core with the minimum voltage and an undervoltage threshold of the electrical core with the minimum voltage, wherein the discharge voltage control threshold is greater than the undervoltage threshold; and

determining a target discharge power limit of the battery pack through a discharge interpolation algorithm based on the estimated discharge voltage, the static discharge power limit, the discharge voltage control threshold, the undervoltage threshold, and a minimum power limit of an integrated vehicle when the estimated discharge voltage falls between the discharge voltage control threshold of the electrical core with the minimum voltage and the undervoltage threshold of the electrical core with the minimum voltage.

2. The method according to claim 1 , wherein the obtaining a static discharge power limit of the battery pack comprises:

obtaining a minimum state of charge value of electrical cores in the battery pack;

obtaining a first temperature of the battery pack; and

querying, based on the minimum state of charge value and the first temperature of the battery pack, a preset first correspondence table of a state of charge, a temperature, and a discharge power to obtain the static discharge power limit.

3. The method according to claim 1 , wherein the calculating, based on the actual minimum cell voltage, an estimated discharge voltage of the electrical core with the minimum voltage for use when the battery pack is discharged based on the static discharge power limit comprises:

obtaining the actual minimum cell voltage of the electrical core with the minimum voltage in the battery pack, an actual discharge current of the electrical core with the minimum voltage, and a corresponding discharge-state internal resistance of the electrical core with the minimum voltage;

determining a discharge current limit of the battery pack based on the static discharge power limit; and

determining the estimated discharge voltage of the electrical core with the minimum voltage based on the actual minimum cell voltage of the electrical core with the minimum voltage, the actual discharge current of the electrical core with the minimum voltage, the discharge current limit of the battery pack, and the discharge-state internal resistance of the electrical core with the minimum voltage.

4. The method according to claim 1 , wherein the “determining a target discharge power limit of the battery pack through a discharge interpolation algorithm based on the estimated discharge voltage, the static discharge power limit, the discharge voltage control threshold, the undervoltage threshold, and a minimum power limit of an integrated vehicle when the estimated discharge voltage falls between the discharge voltage control threshold of the electrical core with the minimum voltage and the undervoltage threshold of the electrical core with the minimum voltage” comprises:

using a difference between the estimated discharge voltage and the undervoltage threshold of the electrical core with the minimum voltage as an input error term of a proportional-integral-derivative (PID) algorithm to obtain a discharge correction term;

correcting the discharge interpolation algorithm based on the discharge correction term; and

calculating the target discharge power limit of the battery pack through the corrected discharge interpolation algorithm based on the estimated discharge voltage, the static discharge power limit, the discharge voltage control threshold, the undervoltage threshold, and the minimum power limit of an integrated vehicle.

5. The method according to claim 4 , wherein the corrected discharge interpolation algorithm is:

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wherein, P max represents the target discharge power limit of the battery pack; P static represents the static discharge power limit of the battery pack; P min represents the minimum power limit of an integrated vehicle; V tg100 is the discharge voltage control threshold of the electrical core with the minimum voltage; V tg0 is the undervoltage threshold of the electrical core with the minimum voltage; and ΔV corrected represents the discharge correction term calculated based on the estimated discharge voltage and the undervoltage threshold.

6. A method for estimating a power limit of a battery pack, comprising:

obtaining an actual maximum cell voltage of an electrical core with a maximum voltage in the battery pack;

obtaining a static charge power limit of the battery pack;

calculating, based on the actual maximum cell voltage, an estimated charge voltage of the electrical core with the maximum voltage for use when the battery pack is charged based on the static charge power limit;

determining whether the estimated charge voltage falls between a charge voltage control threshold of the electrical core with the maximum voltage and an overvoltage threshold of the electrical core with the maximum voltage, wherein the charge voltage control threshold is less than the overvoltage threshold; and

determining a target charge power limit of the battery pack through a charge interpolation algorithm based on the estimated charge voltage, the static charge power limit, the charge voltage control threshold, the overvoltage threshold, and a minimum power limit of an integrated vehicle when the estimated charge voltage falls between the charge voltage control threshold of the electrical core with the maximum voltage and the overvoltage threshold of the electrical core with the maximum voltage.

7. The method according to claim 6 , wherein the obtaining a static charge power limit of the battery pack comprises:

obtaining a maximum state of charge value of electrical cores in the battery pack and a second temperature of the battery pack; and

querying, based on the maximum state of charge value and the second temperature of the battery pack, a preset second correspondence table of a state of charge, a temperature, and a charge power to obtain the static charge power limit.

8. The method according to claim 6 , wherein the calculating, based on the actual maximum cell voltage, an estimated charge voltage of the electrical core with the maximum voltage for use when the battery pack is charged based on the static charge power limit comprises:

obtaining the actual maximum cell voltage of electrical cores in the battery pack, an actual charge current of the electrical core with the maximum voltage, and a corresponding charge-state internal resistance of the electrical core with the maximum voltage;

determining a charge current limit of the battery pack based on the static charge power limit of the battery pack; and

determining the estimated charge voltage based on the actual maximum cell voltage, the actual charge current, the charge current limit, and the charge-state internal resistance.

9. The method according to claim 6 , wherein the “determining a target charge power limit of the battery pack through a charge interpolation algorithm based on the estimated charge voltage, the static charge power limit, the charge voltage control threshold, the overvoltage threshold, and a minimum power limit of an integrated vehicle when the estimated charge voltage falls between the charge voltage control threshold of the electrical core with the maximum voltage and the overvoltage threshold of the electrical core with the maximum voltage” comprises:

using a difference between the estimated charge voltage and the overvoltage threshold of the electrical core with the maximum voltage as an input error term of a PID algorithm to obtain a charge correction term;

correcting the charge interpolation algorithm based on the charge correction term; and

calculating the target charge power limit of the battery pack through the corrected charge interpolation algorithm based on the estimated charge voltage, the static charge power limit, the charge voltage control threshold, the overvoltage threshold, and the minimum power limit of an integrated vehicle.

10. The method according to claim 9 , wherein the corrected charge interpolation algorithm is:

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wherein, P′ max represents the target charge power limit of the battery pack; P′ static represents the static charge power limit of the battery pack; P′ min represents the minimum power limit of an integrated vehicle; V′ tg100 is the charge voltage control threshold of the electrical core with the maximum voltage; V′ tg0 is the overvoltage threshold of the electrical core with the maximum voltage; and ΔV′ corrected represents the charge correction term calculated based on the estimated charge voltage and the overvoltage threshold.

11. A device for estimating a power limit of a battery pack, comprising a processor and a memory storing a plurality of modules to be executed by the processor, the plurality of modules further including:

a first obtaining module, configured to obtain an actual minimum cell voltage of an electrical core with a minimum voltage in the battery pack;

a second obtaining module, configured to obtain a static discharge power limit of the battery pack;

a first calculation module, configured to calculate, based on the actual minimum cell voltage, an estimated discharge voltage of the electrical core with the minimum voltage for use when the battery pack is discharged based on the static discharge power limit;

a first determining module, configured to determine whether the estimated discharge voltage falls between a discharge voltage control threshold of the electrical core with the minimum voltage and an undervoltage threshold of the electrical core with the minimum voltage, wherein the discharge voltage control threshold is greater than the undervoltage threshold; and

a second determining module, configured to determine a target discharge power limit of the battery pack through a discharge interpolation algorithm based on the estimated discharge voltage, the static discharge power limit, the discharge voltage control threshold, the undervoltage threshold, and a minimum power limit of an integrated vehicle when the estimated discharge voltage falls between the discharge voltage control threshold of the electrical core with the minimum voltage and the undervoltage threshold of the electrical core with the minimum voltage.

12. A device for estimating a power limit of a battery pack, comprising a processor and a memory storing a plurality of modules to be executed by the processor, the plurality of modules further including:

a third obtaining module, configured to obtain an actual maximum cell voltage of an electrical core with a maximum voltage in the battery pack;

a fourth obtaining module, configured to obtain a static charge power limit of the battery pack;

a second calculation module, configured to calculate, based on the actual maximum cell voltage, an estimated charge voltage of the electrical core with the maximum voltage for use when the battery pack is charged based on the static charge power limit;

a third determining module, configured to determine whether the estimated charge voltage falls between a charge voltage control threshold of the electrical core with the maximum voltage and an overvoltage threshold of the electrical core with the maximum voltage, wherein the charge voltage control threshold is less than the overvoltage threshold; and

a fourth determining module, configured to determine a target charge power limit of the battery pack through a charge interpolation algorithm based on the estimated charge voltage, the static charge power limit, the charge voltage control threshold, the overvoltage threshold, and a minimum power limit of an integrated vehicle when the estimated charge voltage falls between the charge voltage control threshold of the electrical core with the maximum voltage and the overvoltage threshold of the electrical core with the maximum voltage.

13. A battery management system, comprising: a processor, a memory, a communications interface, and a communications bus; and the processor, the memory, and the communications interface communicate with each other through the communications bus; and

the memory stores at least one executable instruction, and the executable instruction causes the processor to perform operations of the method for estimating the power limit of the battery pack according to claim 1 .

14. A powered vehicle, wherein the powered vehicle comprises the battery management system according to claim 13 .

15. A non-transitory computer-readable storage medium storing at least one executable instruction that, when being executed on a device, causes the device to perform operations of the method for estimating the power limit of the battery pack according to claim 1 .