阅读说明：本技术 一种混合动力汽车的电池soc管理方法 (Battery SOC management method of hybrid electric vehicle ) 是由 尹建坤 刘建康 李川 于 2020-07-28 设计创作，主要内容包括：本发明公开了一种混合动力汽车的电池SOC管理方法,包括：采集电池的温度,根据温度确定电池当前的SOC上限值、SOC下限值以及SOC中值,根据SOC中值确定电池SOC管理限值,根据电池SOC管理限值进行整车功率分配。本发明提出的管理方法中,根据电池SOC管理限值进行整车功率分配,可以保证电池在不过充、过放的前提下,充分发挥动力电池在混动车型对主功率源的辅助调节作用的同时,提高电池的工作效率,延长电池的使用寿命,进而提高整车经济性。(The invention discloses a battery SOC management method of a hybrid electric vehicle, which comprises the following steps: the method comprises the steps of collecting the temperature of a battery, determining the current SOC upper limit value, the current SOC lower limit value and the current SOC middle value of the battery according to the temperature, determining the battery SOC management limit value according to the SOC middle value, and distributing the power of the whole vehicle according to the battery SOC management limit value. According to the management method provided by the invention, the power distribution of the whole vehicle is carried out according to the SOC management limit value of the battery, so that the auxiliary regulation effect of the power battery on the main power source of the hybrid vehicle type can be fully exerted on the premise that the battery is not charged or overdischarged, the working efficiency of the battery is improved, the service life of the battery is prolonged, and the economy of the whole vehicle is further improved.)

1. A battery SOC management method for a hybrid vehicle, comprising:

collecting the temperature of the battery, determining the current SOC upper limit value, the current SOC lower limit value and the current SOC median value of the battery according to the temperature,

and determining a battery SOC management limit value according to the SOC median value, and distributing the power of the whole vehicle according to the battery SOC management limit value.

2. The battery SOC management method of a hybrid vehicle according to claim 1, wherein the SOC management limit includes a driving power generation SOC value,

and the running power generation SOC value is used for distributing the power of the whole vehicle when the vehicle is in an engine driving mode.

3. The battery SOC management method of a hybrid vehicle of claim 1, wherein the SOC management limit includes a regenerative braking SOC value,

and the regenerative braking SOC value is used for distributing the power of the whole vehicle when the vehicle is in a shutdown and coasting mode.

4. The battery SOC management method of a hybrid vehicle of claim 1, wherein the SOC management limit includes an electric-only SOC value,

and the pure electric SOC value is used for distributing the power of the whole vehicle when the vehicle is in a battery driving mode.

5. The battery SOC management method of a hybrid vehicle of claim 1, wherein the SOC management limit includes an assist SOC value,

and the power-assisted SOC value is used for distributing the power of the whole vehicle when the vehicle is in a hybrid driving mode.

6. The battery SOC management method of a hybrid vehicle according to claim 1, wherein a temperature zone in which the battery is located is determined according to the temperature,

and determining the current SOC upper limit value, the current SOC lower limit value and the current SOC median value of the battery according to the temperature interval.

7. The method of managing battery SOC of a hybrid vehicle according to claim 2, wherein the distributing the vehicle power by the vehicle driving power generation SOC value includes:

and acquiring the current SOC value of the battery, and controlling the battery to collect the surplus power output by the engine if the SOC value is smaller than the running power generation SOC value.

8. The battery SOC management method of a hybrid vehicle of claim 3, wherein the entire vehicle power distribution via the regenerative braking SOC value includes:

and acquiring the current SOC value of the battery, and controlling the battery to prohibit collecting the inertia power of the vehicle during sliding if the SOC value is larger than the regenerative braking SOC value.

9. The battery SOC management method of a hybrid vehicle of claim 4, wherein the entire vehicle power distribution via the electric-only SOC values comprises:

and acquiring the current SOC value of the battery, and if the SOC value is smaller than the pure electric SOC value, controlling the vehicle to be forbidden to be in the battery driving mode.

10. The battery SOC management method of a hybrid vehicle of claim 5, wherein the performing the entire vehicle power distribution via the boost SOC value comprises:

and acquiring the current SOC value of the battery, and if the SOC value is smaller than the power-assisted SOC value, controlling the vehicle to be forbidden to be in the hybrid driving mode.

Technical Field

The embodiment of the invention relates to the technology of hybrid electric vehicles, in particular to a battery SOC management method of a hybrid electric vehicle.

Background

The hybrid electric vehicle comprises a motor driving system and an engine driving system, the driving power of the hybrid electric vehicle is independently provided by a single driving system or provided by two driving systems together according to the actual vehicle driving state, and the functions of idle stop, auxiliary driving, regenerative braking energy recovery and the like can be realized by the hybrid electric vehicle with the motor driving system.

The battery is an important component of the motor driving system, the battery can be used as an energy source of the motor driving system to output electric energy outwards, and can also be used for storing electric energy generated when the motor is in a charging mode, and how to perform SOC management on the battery in the whole vehicle system is a key point of whole vehicle hybrid control.

Disclosure of Invention

The invention provides a battery SOC management method of a hybrid electric vehicle, which aims to improve the working efficiency of a battery, prolong the service life of the battery and improve the economy of the whole vehicle.

The embodiment of the invention provides a battery SOC management method of a hybrid electric vehicle, which comprises the following steps:

collecting the temperature of the battery, determining the current SOC upper limit value, the current SOC lower limit value and the current SOC median value of the battery according to the temperature,

and determining a battery SOC management limit value according to the SOC median value, and distributing the power of the whole vehicle according to the battery SOC management limit value.

Further, the SOC management limit includes a driving power generation SOC value, and the driving power generation SOC value is used for distributing the vehicle power when the vehicle is in the engine driving mode.

Further, the SOC management limit includes a regenerative braking SOC value, and the regenerative braking SOC value is used for distributing the vehicle power when the vehicle is in the stop coasting mode.

Further, the SOC management limit includes a pure electric SOC value, and the pure electric SOC value is used for distributing the vehicle power when the vehicle is in the battery driving mode.

Further, the SOC management limit includes an assist SOC value, and the assist SOC value is used for distributing the vehicle power when the vehicle is in the hybrid driving mode.

Further, a temperature interval where the battery is located is determined according to the temperature, and a current SOC upper limit value, a current SOC lower limit value and a current SOC median value of the battery are determined according to the temperature interval.

Further, the power distribution of the whole vehicle through the driving power generation SOC value comprises the following steps: and acquiring the current SOC value of the battery, and controlling the battery to collect the surplus power output by the engine if the SOC value is smaller than the running power generation SOC value.

Further, the power distribution of the whole vehicle through the regenerative braking SOC value comprises: and acquiring the current SOC value of the battery, and controlling the battery to prohibit collecting the inertia power of the vehicle during sliding if the SOC value is larger than the regenerative braking SOC value.

Further, the whole vehicle power distribution through the pure electric SOC value comprises the following steps: and acquiring the current SOC value of the battery, and if the SOC value is smaller than the pure electric SOC value, controlling the vehicle to be forbidden to be in the battery driving mode.

Further, the power distribution of the whole vehicle through the power assisting SOC value comprises the following steps: and acquiring the current SOC value of the battery, and if the SOC value is smaller than the power-assisted SOC value, controlling the vehicle to be forbidden to be in the hybrid driving mode.

Compared with the prior art, the invention has the beneficial effects that: according to the management method provided by the invention, the battery SOC management limit value is adopted, the power distribution of the whole vehicle is carried out according to the battery SOC management limit value, the auxiliary regulation effect of the hybrid vehicle type on the main power source of the power battery can be fully exerted on the premise that the battery is not overcharged or overdischarged (the main power source is supplemented to meet the requirement of the whole vehicle when the main power source is insufficient, and the redundant power of the main power source is absorbed when the main power source is redundant to recover the braking energy of the vehicle), the working efficiency of the battery is improved, the service life of the battery is prolonged, and the economy of the whole vehicle is further improved.

Drawings

FIG. 1 is a flow chart of a management method in an embodiment;

FIG. 2 is a block diagram of a parallel hybrid configuration in an embodiment;

FIG. 3 is a block diagram of a power coupling configuration in an embodiment;

FIG. 4 is a diagram illustrating battery SOC management limits in an embodiment;

fig. 5 is a graph of engine characteristics in the embodiment.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.

Fig. 1 is a flowchart of a management method in an embodiment, and referring to fig. 1, a battery SOC management method for a hybrid vehicle includes:

s1, collecting the temperature of a battery, and determining the current SOC upper limit value, the current SOC lower limit value and the current SOC median value of the battery according to the temperature.

In this step, the temperature of the battery may be collected by a Vehicle Control Unit (VCU), for example, the temperature of the battery may be collected once in each period according to a set time interval, and the SOC upper limit value, the SOC lower limit value, and the SOC median value may be determined according to the battery temperature collected in each period; the temperature of the battery can be acquired in real time, the temperature range is judged, and the SOC upper limit value, the SOC lower limit value and the SOC median value are determined according to the temperature range, so that unnecessary judgment calculation is avoided, the VCU can generate an effective control strategy, and meanwhile, the workload of the VCU can be reduced.

For example, the SOC upper limit value refers to an SOC limit value at which charging cannot be continued any more at the current temperature, and the SOC lower limit value refers to an SOC limit value at which discharging cannot be continued any more at the current temperature. The SOC median may be an average value calculated from the SOC upper limit value and the SOC lower limit value, or an SOC value adapted to the current SOC upper limit value and SOC lower limit value and located between the SOC upper limit value and the SOC lower limit value.

For example, in this step, the SOC upper limit value, the SOC lower limit value, and the SOC median value may be determined according to the collected battery temperature by a fuzzy control method, or according to a preset temperature-SOC value curve (e.g., MAP).

And S2, determining a battery SOC management limit value according to the SOC median value.

For example, in this embodiment, the SOC management limit includes several SOC values, where different SOC management limits may be obtained according to a set rule, for example, by shifting the SOC median up and down.

In different driving modes, for example, an engine driving mode, a battery driving mode or a hybrid power mode, the vehicle controller may generate a battery control strategy for the driving mode according to the SOC value corresponding to the driving mode, and further perform power distribution of the vehicle.

And S3, distributing the power of the whole vehicle according to the SOC management limit value of the battery.

In this step, the vehicle controller allocates power to the vehicle in the specific driving mode according to a predetermined battery control strategy.

In the embodiment, the management method adopts the battery SOC management limit value, and the power distribution of the whole vehicle is carried out according to the battery SOC management limit value, so that the auxiliary regulation effect of the hybrid vehicle on the main power source of the power battery can be fully exerted on the premise that the battery is not charged or discharged excessively (the main power source is supplemented to meet the requirement of the whole vehicle when the main power source is insufficient, and the redundant power of the main power source is absorbed when the main power source is redundant to recover the braking energy of the vehicle), the working efficiency of the battery is improved, the service life of the battery is prolonged, and the economy of the whole vehicle is further improved.

In this embodiment, the battery SOC management method for a hybrid vehicle may be applied to a parallel hybrid configuration, a power coupling configuration, and other hybrid vehicle types.

Fig. 2 is a block diagram of a parallel hybrid configuration in an embodiment, and referring to fig. 2, for a typical parallel hybrid configuration, which includes a motor 300 having an electric/power generating function, the motor 300 is connected to an engine 200 through a torque coupler 400. The engine 200 is a main power source, the motor-battery system is a secondary power source, and the torque coupler 400 can couple and output the torques of the engine 200 and the motor 300.

Fig. 3 is a block diagram of a power coupling configuration in an embodiment, and referring to fig. 3, for a typical power coupling configuration, the power coupling configuration includes a second electric machine E2 with an electric/power generation function, the second electric machine E2 is mechanically connected with an engine 200 to form an engine-generator system, and is a main power source, a battery 100 is a secondary power source, and a first electric machine E1 receives power input of the main power source and the secondary power source at the same time and outputs torque.

In the hybrid electric vehicle, the whole vehicle can be driven by an engine alone, a battery alone or an engine-battery hybrid, and correspondingly, the vehicle has an engine driving mode, a battery driving mode and a hybrid driving mode.

Fig. 4 is a schematic diagram of a battery SOC management limit in an embodiment, and referring to fig. 4, specifically, the SOC management limit in the embodiment includes a driving power generation SOC value, and the driving power generation SOC value is used for distributing vehicle-finished power when the vehicle is in an engine driving mode. Illustratively, the driving power generation SOC value is obtained by upward shifting the SOC median value by Th 3.

As an implementation scheme, the whole vehicle power distribution through the driving power generation SOC value comprises the following steps: and acquiring the current SOC value of the battery, and controlling the battery to collect the surplus power output by the engine if the SOC value is smaller than the running power generation SOC value.

Fig. 5 is a characteristic diagram of an engine in an embodiment, and in combination with fig. 4 and 5, for example, when the vehicle is in an engine driving mode, if the driver's required torque is in an engine economy optimal curve and the current SOC value of the battery is lower than the driving power generation SOC value, the vehicle control unit controls the engine to operate on the optimal operation curve, and the portion of the engine generated by the engine, which exceeds the driver's required torque, is used for driving the motor to be in a charging mode, so as to charge the battery through the motor. Illustratively, the driving power generation SOC value indicates a maximum SOC value that the battery can absorb excess power from the main power source through the motor, except for the power required by the driver, and when the SOC of the battery is higher than the driving power generation SOC threshold, the excess power of the main power source is prohibited from being charged into the battery during the driving of the entire vehicle, and when the SOC of the battery gradually approaches the driving power generation SOC value, the excess power receivable by the battery is reduced, and the entire vehicle controller performs the distribution of the excess power according to the difference between the current SOC value of the battery and the driving power generation SOC value.

The SOC management limit value also comprises a regenerative braking SOC value, and the regenerative braking SOC value is used for distributing the power of the whole vehicle when the vehicle is in a shutdown sliding mode.

As an implementation scheme, the whole vehicle power distribution through the regenerative braking SOC value comprises the following steps: and acquiring the current SOC value of the battery, and controlling the battery to prohibit collecting the inertia power of the vehicle during sliding if the SOC value is larger than the regenerative braking SOC value. Referring to fig. 4, the regenerative braking SOC value is obtained by shifting the SOC median value up to Th 4.

For example, the regenerative braking SOC value represents a maximum SOC value that the battery can reach to absorb the inertia power generated by the motor during the braking coasting of the vehicle, when the SOC of the battery is higher than the regenerative braking SOC value, the battery is prohibited from energy recovery during the braking, when the SOC of the battery gradually approaches the regenerative braking SOC value, the inertia power that the battery can receive is reduced, and the vehicle controller performs the distribution of the inertia power according to the difference between the current SOC value of the battery and the regenerative braking SOC value.

The SOC management limit value further comprises a pure electric SOC value, and the pure electric SOC value is used for distributing the power of the whole vehicle when the vehicle is in a battery driving mode.

As an implementation scheme, the whole vehicle power distribution through the pure electric SOC value comprises the following steps: and acquiring the current SOC value of the battery, and controlling the vehicle to be forbidden to be in a battery driving mode if the SOC value is smaller than the pure electric SOC value. For example, referring to fig. 4, the electric-only SOC value is obtained by shifting the SOC median value down to Th 2. For example, the electric-only SOC value indicates a lowest limit value when the battery maintains the vehicle in the battery driving mode, and when the current SOC value of the battery is lower than the electric-only SOC value, the vehicle controller controls the vehicle to be in the engine driving mode or the hybrid driving mode.

The SOC management limit value also comprises an assistance SOC value, and the assistance SOC value is used for distributing the power of the whole vehicle when the vehicle is in a hybrid driving mode.

As an implementation scheme, the whole vehicle power distribution through the power assisting SOC value comprises the following steps: and acquiring the current SOC value of the battery, and controlling the vehicle to be forbidden to be in a hybrid driving mode if the SOC value is smaller than the power-assisted SOC value. Illustratively, referring to fig. 4, the boost SOC value is obtained by shifting the SOC median value up to Th 5.

Referring to fig. 4 and 5, for example, the assist SOC value represents a lowest battery SOC value when the battery can be used as the secondary power source, if the current SOC value of the battery is greater than the assist SOC value and the driver's required torque is above the maximum external characteristic curve of the engine, the vehicle controller controls the battery and the motor to provide torque that the engine cannot provide to meet the driving requirement, and when the current SOC value of the battery is lower than the assist SOC value, the vehicle controller prohibits the battery-motor from being used as the secondary power source. When the SOC of the battery gradually approaches to the power assisting SOC value, the auxiliary power provided by the battery is reduced, and the vehicle control unit distributes the auxiliary power according to the difference value between the current SOC value and the power assisting SOC value of the battery.

In this embodiment, the offsets Th2, Th3, Th4 and Th5 are obtained by a calibration test, and when the calibration test is performed, one battery temperature corresponds to a set of SOC upper limit value, SOC lower limit value, SOC median value, Th2, Th3, Th4 and Th 5. For example, when the battery temperature is determined, the SOC upper limit value and the SOC lower limit value may be determined based on the battery service life, an average value of the SOC upper limit value and the SOC lower limit value is used as an SOC median value, the depth of discharge DOD is determined according to the battery service life at the current temperature, and then the offset is calculated according to the depth of discharge, using the following formula:

Th2＝DOD*K1；Th3＝DOD*K2；Th4＝DOD*K3；Th5＝DOD*K4

in the formula, K1, K2, K3 and K4 are bias coefficients, wherein K1, K2, K3 and K4 are fixed values configured during calibration tests, and the value of the bias coefficient is smaller than 1.

In this embodiment, the battery SOC management limit includes a driving power generation SOC value, a regenerative braking SOC value, a pure electric SOC value, and a power assisting SOC value, and the vehicle control unit may perform vehicle power distribution according to the SOC values, so that the working curve of the engine may be as close as possible to the optimal economic curve of the engine on the premise that the battery is not overcharged or overdischarged, so as to improve the vehicle economy.

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.