Control method and system for maximum allowable power of power battery and extended-range hybrid vehicle

Abstract

The present invention discloses a control method, system and range-extended hybrid vehicle for the maximum allowable power of a power battery. The control method includes: according to the current power battery SOC value SOC0, the current power battery minimum available SOC value SOC min and the current maximum discharge power of the power battery P max , calculate the first allowable power P1 of the power battery; if the vehicle is in the starting condition or transient acceleration condition, then according to the current vehicle speed and the current accelerator pedal opening, the second allowable power P2 of the power battery is obtained, so that the current maximum allowable power P of the power battery is en =min(max(P2,P1),P max Otherwise, the maximum allowable power of the current power battery is P en =P1. The present invention can slow down the rate of power battery charge loss in low-power situations, improve the vehicle's ability to maintain power, and avoid the problem of severe slowdown in power response during vehicle starting or transient acceleration.

Description

Technical Field

[0001] The present invention belongs to the field of power batteries, and in particular relates to a method and system for controlling the maximum allowable power of a power battery and an extended-range hybrid vehicle. Background Art

[0002] Currently, extended-range hybrid vehicles (i.e., extended-range hybrid new energy vehicles) are powered by a power battery and an engine. While the vehicle is in motion, the power battery supplies power to the drive motor, while the engine's output power is generated by the generator and then supplied to the drive motor and power battery. Generally, the maximum discharge power of the power battery is much greater than the maximum output power of the engine, and there is a certain lag in engine power output. During rapid acceleration, the vehicle's power demand is high, and the vehicle's drive motor will first utilize the available discharge power of the power battery. Therefore, under certain operating conditions, particularly during long uphill descents and frequent rapid acceleration, the power battery charge will gradually decrease until it reaches zero, even if the engine is running.

[0003] To prevent the vehicle from stalling due to the battery's charge dropping to zero, the battery management system in extended-range hybrid vehicles typically limits the (permitted) discharge power of the power battery when the battery charge drops below a certain level. When the power battery's discharge power is limited to a lower value, the power required to drive the motor during acceleration is generated by the engine's output power, which is then passed through the generator. However, since the engine's output power is low and its response is slow at low speeds, the vehicle's dynamic response is slow, and it may even be unable to start on a slope or under certain road conditions.

[0004] When the power battery is low, how to control the maximum allowable power of the power battery and use the discharge power of the power battery within the maximum allowable power range of the power battery (corresponding to the discharge power of the power battery that can be used being less than or equal to the maximum allowable power of the power battery) to avoid further rapid reduction of power while avoiding a major impact on the vehicle's starting and acceleration power response is an urgent problem that needs to be solved. Summary of the Invention

[0005] The purpose of the present invention is to provide a method and system for controlling the maximum allowable power of a power battery, and an extended-range hybrid vehicle, so as to slow down the rate of decrease of the power battery power under low-power conditions, improve the vehicle's power maintenance capability, and avoid the problem of severe slowdown of the vehicle's power response during starting or transient acceleration.

[0006] In a first aspect, the method for controlling the maximum allowable power of a power battery according to the present invention includes:

[0007] According to the current power battery SOC value SOC0, the current power battery minimum available SOC value SOC minand the current maximum discharge power of the power battery P max , calculate the first allowable power P1 of the power battery.

[0008] If the vehicle is in the starting condition or transient acceleration condition, the preset second allowable power table of the power battery is queried according to the current vehicle speed and the current accelerator pedal opening, and the second allowable power of the power battery P2 is obtained, so that the current maximum allowable power of the power battery P en = min(max(P2, P1) , P max ), that is, min(max(P2, P1), P max ) is assigned to P en Otherwise (i.e. the vehicle is neither in the starting condition nor in the transient acceleration condition; it also means the vehicle is in other conditions except starting and transient acceleration), the current maximum allowable power of the power battery is P en = P1, that is, the first allowable power of the power battery P1 is assigned to P en .

[0009] Among them, max(P2, P1) means taking the maximum value of P2 and P1, min(max(P2, P1) , P max ) means taking max(P2, P1) and P max The preset second allowable power table of the power battery is a correspondence table of vehicle speed, accelerator pedal opening and the second allowable power of the power battery obtained through calibration.

[0010] Preferably, taking the road slope into consideration, after obtaining the second allowable power P2 of the power battery, the following steps are performed:

[0011] Use the formula: P'2=k* P2 to correct P2 and obtain the corrected second allowable power P'2 of the power battery.

[0012] The maximum allowable power of the current power battery is P en = min(max(P'2, P1) , P max ). max(P'2, P1) means taking the maximum value of P'2 and P1, min(max(P'2, P1) , P max ) means taking max(P'2, P1) and P max The minimum value in .

[0013] Among them, k represents the current power correction coefficient, k≥1, k is obtained by querying the preset power correction coefficient table according to the current road slope and the current vehicle speed. The preset power correction coefficient table is a correspondence table of road slope, vehicle speed and power correction coefficient obtained through calibration.

[0014] Preferably, the first allowable power P1 of the power battery is calculated as follows:

[0015] Get the current power battery SOC value SOC0 and the current power battery maximum discharge power P max .

[0016] According to the current power battery temperature, query the preset power battery temperature and the power battery minimum available SOC value corresponding relationship table to obtain the current power battery minimum available SOC value SOC min .

[0017] Use the formula: ΔSOC= SOC0-SOC min , calculate the current SOC difference ΔSOC.

[0018] According to the current SOC difference ΔSOC, a preset correspondence table between SOC differences and power limit coefficients is searched to obtain the current power limit coefficient η; wherein 0≤η≤1.

[0019] Using the formula: P1= η*P max , calculate and obtain the first allowable power P1 of the power battery.

[0020] Preferably, in the correspondence table between the preset SOC difference and the power limit coefficient, when the SOC difference is greater than or equal to the first preset SOC threshold, the power limit coefficient is 1; when the SOC difference is greater than 0 and less than the first preset SOC threshold, the power limit coefficient decreases as the SOC difference decreases; when the SOC difference is equal to 0, the power limit coefficient is 0.

[0021] Preferably, if conditions 1a to 1d are met at the same time, the vehicle is determined to be in a starting condition; among them, condition 1a: the vehicle gear is D gear or R gear; condition 1b: the current vehicle speed is less than the preset vehicle speed threshold; condition 1c: the driver's original required torque T is greater than the first preset torque threshold; condition 1d: the starting flag changes from 0 to 1.

[0022] Preferably, if conditions 2a to 2e are met at the same time, the vehicle is determined to be in a transient acceleration condition; wherein, condition 2a: the vehicle gear is D gear; condition 2b: the current vehicle speed is greater than the preset vehicle speed threshold; condition 2c: the driver's original required torque T is greater than the first preset torque threshold; condition 2d: the difference between the driver's original required torque T and the filtered driver's required torque T' is greater than x*T; condition 2e: the transient acceleration flag changes from 0 to 1.

[0023] The current accelerator pedal opening is used to query a preset correspondence table between the accelerator pedal opening and the driver's original torque demand to obtain the driver's original torque demand T. The driver's original torque demand T is first-order filtered to obtain the filtered driver's torque demand T'; x represents a preset torque coefficient, where 0 < x < 0.5.

[0024] Preferably, the first preset torque threshold is the vehicle creep torque, and the preset torque coefficient x=0.1.

[0025] Preferably, if both conditions 3a and 3b are met, the vehicle is determined to have completed its launch. Condition 3a: The current vehicle speed is greater than a preset speed threshold; Condition 3b: The launch flag changes from 1 to 0. If both conditions 4a and 4b are met, the vehicle is determined to have completed transient acceleration. Condition 4a: The difference between the driver's original requested torque T and the filtered driver's requested torque T' is less than x*T; Condition 4b: The transient acceleration flag changes from 1 to 0.

[0026] Preferably, after the vehicle completes starting or after the vehicle completes transient acceleration, a first-order filtering method is used to make the current maximum allowable power of the power battery P en By min(max(P2, P1) , P max ) or min(max(P'2, P1) , P max ) gradually transition to P1.

[0027] In a second aspect, the control system for the maximum allowable power usage of a power battery according to the present invention includes a controller configured to execute the above-mentioned method for controlling the maximum allowable power usage of a power battery.

[0028] In a third aspect, the extended-range hybrid vehicle described in the present invention includes the above-mentioned control system for the maximum allowable power usage of the power battery.

[0029] The present invention has the following effects:

[0030] (1) According to SOC0, SOC min and P max , calculate the first allowable power P1 of the power battery. When the vehicle is neither in the starting condition nor in the transient acceleration condition, the discharge power of the power battery (i.e., low-battery time-limited power) is used within the first allowable power range of the power battery (i.e., less than or equal to the P1 range). This reduces the discharge power of the power battery during low-battery uniform acceleration and uniform speed driving, slows down the rate of power battery charge decline, and improves the vehicle's ability to maintain power.

[0031] (2) Determine the second allowable power P2 of the power battery according to the current vehicle speed and the current accelerator pedal opening. When the vehicle is in the starting condition or transient acceleration condition, the second allowable power P2 of the power battery is determined in the range of min(max(P2, P1) , P max ) range (i.e. less than or equal to min(max(P2, P1) , P max ) range), which uses the discharge power of the power battery to slow down the rate of power battery power decline and avoid the problem of severe slowdown in power response when the vehicle starts or during transient acceleration. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a flow chart of a method for controlling the maximum allowable power of a power battery in an embodiment of the present invention.

[0033] Figure 2 This is a flow chart of another method for controlling the maximum allowable power of a power battery in an embodiment of the present invention.

[0034] Figure 3 Flowchart for calculating the first allowable power P1 of the power battery in an embodiment of the present invention. DETAILED DESCRIPTION

[0035] In order to enable a more detailed understanding of the features and technical contents of the embodiments of the present invention, the implementation of the embodiments of the present invention is described in detail below with reference to the accompanying drawings. The accompanying drawings are for reference only and are not intended to limit the embodiments of the present invention.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention pertains. The terms used herein are for the purpose of describing embodiments of the present invention only and are not intended to limit the present invention.

[0037] In the following description, reference is made to “some embodiments”, which describes a subset of all possible embodiments, but it will be understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0038] Signals involved in the embodiment of the present invention: current power battery temperature, current power battery SOC value SOC0 and current power battery maximum discharge power P max The current vehicle speed, accelerator pedal position, and road slope are obtained from the battery management system. These acquisition methods are all based on existing technologies.

[0039] like Figure 1 As shown, a method for controlling the maximum allowable power of a power battery in an embodiment of the present invention includes:

[0040] Step 1: Based on the current power battery SOC value SOC0 and the current power battery minimum available SOC value SOC min and the current maximum discharge power of the power battery P max , calculate the first allowable power P1 of the power battery, and then execute step 2.

[0041] Step 2: Determine whether the vehicle is in the starting condition. If so, proceed to step 5; otherwise, proceed to step 3.

[0042] Step 3: Determine whether the vehicle is in a transient acceleration state. If yes, proceed to step 7; otherwise, proceed to step 4.

[0043] Step 4: Set the current maximum allowable power of the power battery to P en = P1, that is, the first allowable power of the power battery P1 is assigned to P en , then return to step 1.

[0044] Step 5: According to the current vehicle speed and the current accelerator pedal opening, query the preset second allowable power table of the power battery to obtain the second allowable power P2 of the power battery, so that the current maximum allowable power P of the power battery is en = min(max(P2, P1) , P max ), that is, min(max(P2, P1), P max ) is assigned to P en , then execute step 6. Among them, max(P2, P1) means taking the maximum value of P2 and P1, min(max(P2, P1) , P max ) means taking max(P2, P1) and P max The preset second allowable power table of the power battery is a correspondence table of vehicle speed, accelerator pedal opening and the second allowable power of the power battery obtained through calibration.

[0045] The second allowable power P2 of the power battery satisfies the discharge power required for transient acceleration and starting of the vehicle. First, take the larger of P2 and P1, and then add P2 to the power max The smaller of the two values ​​is taken as the maximum allowable power of the power battery under the starting condition or transient acceleration condition, which avoids the unreasonable situation that the maximum allowable power of the power battery under the starting condition or transient acceleration condition is smaller than the maximum allowable power of the power battery under other conditions, and also ensures that the maximum allowable power of the power battery under any condition will be less than or equal to P max .

[0046] Step 6: Determine whether the start is completed. If so, proceed to step 9; otherwise, continue to step 6.

[0047] Step 7: According to the current vehicle speed and the current accelerator pedal opening, query the preset power battery second allowable power table to obtain the power battery second allowable power P2, so that the current power battery maximum allowable power P en = min(max(P2, P1) , P max ), that is, min(max(P2, P1), P max ) is assigned to P en , then proceed to step eight.

[0048] Step 8: Determine whether transient acceleration is completed. If yes, proceed to step 9; otherwise, continue to step 8.

[0049] Step 9: Use the first-order filtering method to make the current maximum allowable power of the power battery P en By min(max(P2,P1) , P max ) gradually transitions to P1, and then returns to step 1. The filter coefficient of the first-order filter is a preset value calibrated according to the drivability of the vehicle, and the first-order filtering method belongs to the existing conventional technology.

[0050] like Figure 2 As shown, another method for controlling the maximum allowable power of a power battery in an embodiment of the present invention includes:

[0051] Step 1: Based on the current power battery SOC value SOC0 and the current power battery minimum available SOC value SOC min and the current maximum discharge power of the power battery P max , calculate the first allowable power P1 of the power battery, and then execute step 2.

[0052] Step 2: Determine whether the vehicle is in the starting condition. If so, proceed to step 5; otherwise, proceed to step 3.

[0053] Step 3: Determine whether the vehicle is in a transient acceleration state. If yes, proceed to step 9; otherwise, proceed to step 4.

[0054] Step 4: Set the current maximum allowable power of the power battery to P en = P1, that is, the first allowable power of the power battery P1 is assigned to P en , then return to step 1.

[0055] Step 5: According to the current vehicle speed and the current accelerator pedal opening, query the preset power battery second allowable power table to obtain the power battery second allowable power P2, and then execute step 6.

[0056] Step 6. Use the formula: P'2 = k * P2 to correct P2 to obtain the corrected second allowable power of the power battery, P'2, and then proceed to Step 7. Here, k represents the current power correction factor, k ≥ 1. k is obtained by querying a preset power correction factor table based on the current road slope and current vehicle speed. The preset power correction factor table is a table of correspondences between road slope, vehicle speed, and power correction factors obtained through calibration. In the preset power correction factor table, at the same vehicle speed, the greater the road slope, the greater the power correction factor.

[0057] Step 7: Set the current maximum allowable power of the power battery to P en = min(max(P'2, P1) , P max ), then execute step 8. Wherein, max(P'2, P1) means taking the maximum value of P'2 and P1, min(max(P'2, P1) , P max ) means taking max(P'2, P1) and P max The preset second allowable power table of the power battery is a correspondence table of vehicle speed, accelerator pedal opening and the second allowable power of the power battery obtained through calibration.

[0058] Step 8: Determine whether the start is completed. If so, proceed to step 13; otherwise, continue to step 8.

[0059] Step 9: According to the current vehicle speed and the current accelerator pedal opening, query the preset second allowable power table of the power battery to obtain the second allowable power P2 of the power battery, and then execute step 10.

[0060] Step 10: Use the formula: P'2=k*P2 to correct P2 to obtain the corrected second allowable power of the power battery P'2, and then execute step 11.

[0061] Step 11: Set the current maximum allowable power of the power battery to P en = min(max(P'2, P1) , P max ), then proceed to step 12.

[0062] Step 12: Determine whether transient acceleration is completed. If so, proceed to step 13; otherwise, continue to step 12.

[0063] Step 13: Use the first-order filtering method to make the current maximum allowable power of the power battery P en By min(max(P'2, P1) , P max) gradually transitions to P1, and then returns to step 1. The filter coefficient of the first-order filter is a preset value calibrated according to the drivability of the vehicle, and the first-order filtering method belongs to the existing conventional technology.

[0064] Typically, the maximum discharge power of a range-extended hybrid vehicle's power battery is significantly greater than the engine's maximum power. Therefore, under certain operating conditions (such as during continuous hill climbing), the battery's charge level will continue to decrease. To prevent the battery's charge from rapidly decreasing, or even reaching zero, as the charge level decreases, the battery's discharge power must be limited. Furthermore, a portion of the battery's charge must be reserved and not used. This reserved charge is the battery's minimum available SOC value. The battery's minimum available SOC value is related to the battery's temperature.

[0065] In some embodiments, as Figure 3 As shown, the method for calculating the first allowable power P1 of the power battery is:

[0066] The first step is to obtain the current power battery SOC value SOC0 and the current power battery maximum discharge power P max .

[0067] Step 2: According to the current power battery temperature, query the preset power battery temperature and the power battery minimum available SOC value corresponding relationship table to obtain the current power battery minimum available SOC value SOC min In the preset corresponding relationship table between power battery temperature and power battery minimum available SOC value (obtained through calibration), the higher the power battery temperature, the smaller the power battery minimum available SOC value, and the lower the power battery temperature, the larger the power battery minimum available SOC value. As an example, the minimum available SOC value of the power battery is usually in the range of 3% to 5%. For example, when the power battery temperature is 20°C, the SOC min =3%, when the power battery temperature is -20℃, SOC min =5%. When the power battery temperature is between -20℃ and 20℃, the minimum available SOC value of the power battery is between 3% and 5% based on the corresponding relationship between the power battery temperature and the minimum available SOC value of the power battery.

[0068] Step 3: Use the formula: ΔSOC = SOC0-SOC min , calculate the current SOC difference ΔSOC.

[0069] Step 4: Based on the current SOC difference ΔSOC, query a preset table of correspondences between SOC differences and power limit coefficients to obtain the current power limit coefficient η, where 0 ≤ η ≤ 1. In the preset table of correspondences between SOC differences and power limit coefficients (obtained through calibration), when the SOC difference is greater than or equal to a first preset SOC threshold, the power limit coefficient is 1. When the SOC difference is greater than 0 and less than the first preset SOC threshold (indicating a low battery), the power limit coefficient decreases as the SOC difference decreases. When the SOC difference is equal to 0, the power limit coefficient is 0. As an example, the first preset SOC threshold is 20%.

[0070] Step 5: Use the formula: P1= η*P max , calculate and obtain the first allowable power P1 of the power battery.

[0071] In some embodiments, if conditions 1a to 1d are simultaneously met, the vehicle is determined to be in a starting state, and if conditions 3a and 3b are simultaneously met, the vehicle is determined to have completed the start. Condition 1a: The vehicle gear is in D or R; Condition 1b: The current vehicle speed is less than a preset speed threshold; Condition 1c: The driver's original requested torque T is greater than a first preset torque threshold; Condition 1d: The start flag changes from 0 to 1; Condition 3a: The current vehicle speed is greater than the preset speed threshold; Condition 3b: The start flag changes from 1 to 0.

[0072] In some embodiments, if conditions 2a to 2e are simultaneously met, the vehicle is determined to be in a transient acceleration state. If conditions 4a and 4b are simultaneously met, the vehicle is determined to have completed transient acceleration. Condition 2a includes: the vehicle is in gear D; condition 2b includes: the current vehicle speed is greater than a preset speed threshold; condition 2c includes: the driver's original requested torque T is greater than a first preset torque threshold; condition 2d includes: the difference between the driver's original requested torque T and the filtered driver's requested torque T' is greater than x*T; condition 2e includes: the transient acceleration flag changes from 0 to 1; condition 4a includes: the difference between the driver's original requested torque T and the filtered driver's requested torque T' is less than x*T; and condition 4b includes: the transient acceleration flag changes from 1 to 0.

[0073] Here, the current accelerator pedal opening is used to query a preset correspondence table between accelerator pedal opening and the driver's original torque demand to obtain the driver's original torque demand T. A first-order filter (filtering rate is a preset value) is performed on the driver's original torque demand T to obtain the filtered driver's torque demand T'. x represents a preset torque coefficient, where 0 < x < 0.5. For example, the first preset torque threshold is the vehicle creep torque (e.g., 10 Nm), and the preset torque coefficient x = 0.1. For example, the preset vehicle speed threshold is 5 km / h.

[0074] In the above-mentioned transient acceleration identification method, judgment is made by the difference between the driver's original required torque T and the filtered driver required torque T'. On the one hand, it avoids the problem of frequent changes in the judgment state caused by frequent changes in the accelerator pedal opening when judging by the accelerator pedal opening, and the problem of misjudgment caused by small changes in the accelerator pedal opening; on the other hand, it realizes accurate identification of transient acceleration through the judgment of torque changes, and avoids frequent changes in transient acceleration state. That is, the problem of frequent changes in judgment state caused by torque fluctuations is solved by filtering, and at the same time, the difference between T and T' is required to be less than x*T, thereby realizing accurate identification of transient acceleration.

[0075] Furthermore, the vehicle is considered to have completed transient acceleration when the filtered driver demand torque T' reaches 90% of the original driver demand torque. This precise determination of the moment of completion of transient acceleration is achieved by using the difference between the original driver demand torque and the filtered driver demand torque, avoiding the inaccurate identification of the moment of completion of transient acceleration caused by determining the accelerator pedal position or the duration of the accelerator pedal depression.

[0076] The embodiment of the present invention accurately identifies the starting and transient acceleration conditions of the vehicle. In the case of low battery, on the one hand, within the precise transient acceleration and starting time, the maximum allowable power of the power battery is equal to min(max(P2, P1), P max ) or min(max(P'2, P1) , P max ), which reduces the duration and power of high-power battery discharge during transient acceleration and starting, slows the rate of power battery charge decline, improves the vehicle's ability to maintain charge, and avoids the problem of a severe slowdown in the vehicle's power response during starting or transient acceleration. Furthermore, after the vehicle completes starting or transient acceleration, it returns to the power battery's first allowable power range and uses the power battery's discharge power, reducing the power battery's available power. The engine provides the majority of the power required for uniform acceleration and constant speed driving, further reducing the power battery's discharge power during uniform acceleration and constant speed driving, further reducing the rate of power battery charge decline and improving the vehicle's ability to maintain charge.

[0077] In addition, an embodiment of the present invention further provides a control system for the maximum allowable power usage of a power battery, which includes a controller configured to execute the above-mentioned control method for the maximum allowable power usage of a power battery.

[0078] In addition, an embodiment of the present invention further provides an extended-range hybrid vehicle, which includes the above-mentioned control system for the maximum allowable power of the power battery.

[0079] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with this technical field within the technical scope disclosed in the present invention should be covered by the scope of protection of the present invention.

Claims

1. A method for controlling the maximum allowable power of a power battery, characterized in that: include: According to the current power battery SOC value SOC0, the current power battery minimum available SOC value SOC min and the current maximum discharge power of the power battery P max , calculate the first allowable power P1 of the power battery; If the vehicle is in the starting condition or transient acceleration condition, the preset second allowable power table of the power battery is queried according to the current vehicle speed and the current accelerator pedal opening, and the second allowable power of the power battery P2 is obtained, so that the current maximum allowable power of the power battery P en = min(max(P2 , P1) , P max Otherwise, the maximum allowable power of the current power battery is P en = P1; The method for calculating the first allowable power P1 of the power battery is: Get the current power battery SOC value SOC0 and the current power battery maximum discharge power P max ; According to the current power battery temperature, query the preset power battery temperature and the power battery minimum available SOC value corresponding relationship table to obtain the current power battery minimum available SOC value SOC min ; Use the formula: ΔSOC= SOC0-SOC min , calculate the current SOC difference ΔSOC; According to the current SOC difference ΔSOC, query the preset correspondence table between the SOC difference and the power limit coefficient to obtain the current power limit coefficient η, 0≤η≤1; Using the formula: P1= η*P max , calculate and obtain the first allowable power P1 of the power battery; Among them, max(P2, P1) means taking the maximum value of P2 and P1, min(max(P2, P1) , P max ) means taking max(P2, P1) and P max The preset second allowable power table of the power battery is a correspondence table of vehicle speed, accelerator pedal opening and the second allowable power of the power battery obtained through calibration.

2. The method for controlling the maximum allowable power of a power battery according to claim 1, characterized in that: After obtaining the second allowable power P2 of the power battery, perform the following steps: Use the formula: P'2=k* P2 to correct P2 and obtain the corrected second allowable power of the power battery P'2; The maximum allowable power of the current power battery is P en = min(max(P'2 , P1) , P max ); Among them, k represents the current power correction coefficient, k≥1, k is obtained by querying the preset power correction coefficient table according to the current road slope and the current vehicle speed. The preset power correction coefficient table is a correspondence table of road slope, vehicle speed and power correction coefficient obtained through calibration.

3. The method for controlling the maximum allowable power of a power battery according to claim 2, characterized in that: In the preset correspondence table between the SOC difference and the power limit coefficient, when the SOC difference is greater than or equal to the first preset SOC threshold, the power limit coefficient is 1; when the SOC difference is greater than 0 and less than the first preset SOC threshold, the power limit coefficient decreases as the SOC difference decreases; when the SOC difference is equal to 0, the power limit coefficient is 0.

4. The method for controlling the maximum allowable power of a power battery according to claim 1 or 2, characterized in that: If conditions 1a to 1d are met simultaneously, the vehicle is determined to be in the starting state; wherein condition 1a: the vehicle gear is in D or R; condition 1b: the current vehicle speed is less than a preset speed threshold; condition 1c: the driver's original required torque T is greater than a first preset torque threshold; condition 1d: the starting flag changes from 0 to 1; If conditions 2a to 2e are simultaneously met, the vehicle is determined to be in a transient acceleration state; wherein condition 2a: the vehicle gear is in D gear; condition 2b: the current vehicle speed is greater than a preset vehicle speed threshold; condition 2c: the driver's original requested torque T is greater than a first preset torque threshold; condition 2d: the difference between the driver's original requested torque T and the filtered driver's requested torque T' is greater than x*T; condition 2e: the transient acceleration flag changes from 0 to 1; Among them, according to the current accelerator pedal opening, a preset correspondence table between the accelerator pedal opening and the driver's original required torque is queried to obtain the driver's original required torque T; the driver's original required torque T is first-order filtered to obtain the filtered driver's required torque T'; x represents a preset torque coefficient, 0<x<0.

5.

5. The method for controlling the maximum allowable power of a power battery according to claim 4, characterized in that: The first preset torque threshold is the vehicle creep torque, and the preset torque coefficient x=0.

1.

6. The method for controlling the maximum allowable power of a power battery according to claim 4, characterized in that: If both conditions 3a and 3b are met, the vehicle is determined to have completed starting; condition 3a: the current vehicle speed is greater than the preset vehicle speed threshold; condition 3b: the starting flag changes from 1 to 0; If both conditions 4a and 4b are met, the vehicle is determined to have completed transient acceleration; condition 4a: the difference between the driver's original required torque T and the filtered driver's required torque T' is less than x*T; condition 4b: the transient acceleration flag changes from 1 to 0.

7. The method for controlling the maximum allowable power of a power battery according to claim 6, characterized in that: After the vehicle completes starting or transient acceleration, the first-order filtering method is used to make the current maximum allowable power of the power battery P en By min(max(P2, P1), P max ) or min(max(P'2 , P1) , P max ) gradually transition to P1.

8. A control system for the maximum allowable power of a power battery, comprising a controller, characterized in that: The controller is configured to execute the method for controlling the maximum allowable power of a power battery according to any one of claims 1 to 7.

9. An extended-range hybrid vehicle, characterized in that: The invention comprises a control system for the maximum allowable power usage of a power battery as claimed in claim 8.

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