An electric vehicle composite energy storage system and energy distribution method

Abstract

The application discloses a kind of electric vehicle composite energy storage systems, including power supply module and charging module;The power supply module includes primary power supply unit, secondary power supply unit and tertiary power supply unit;The charging module includes charge control panel, primary charging circuit, secondary charging circuit and tertiary charging circuit;The total capacity of the lithium iron phosphate battery group, lithium air battery group and lithium battery group is 12:5:3, and the allocation method is as follows: S1: when electric automobile starts, lithium iron phosphate battery group will start discharging, and power supply is provided for electric automobile motor;S2: acceleration is carried out by lithium air battery group and lithium battery group array;S3: the lithium air battery group independently supplies power to the electric equipment in the electric automobile except motor.Specifically, the lithium iron phosphate battery group will remain unchanged under the condition of power supply power, the lithium air battery group and the lithium battery group array accelerate, the battery service life is long, the electric loss is low, and the controllability is high.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric vehicle energy storage systems, and particularly relates to an electric vehicle composite energy storage system and an energy distribution method. BACKGROUND

[0002] Now, compared with the transmission car, the electric vehicle has the problems of poor acceleration performance and short driving range, and in the case of high output power, the service life of the power battery will be shortened. Although the lithium iron phosphate battery has high energy density, the power density cannot meet the satisfactory requirements. In order to solve this problem, the common method is to use a composite energy storage system composed of lithium iron phosphate batteries and super capacitors to provide energy for electric vehicles. The super capacitor has high power density and can guarantee the speed requirement of the electric vehicle. The use of lithium iron phosphate battery and super capacitor can improve the service life of the battery. The storage battery provides power through the controller to improve the speed of the electric vehicle under stable power supply, which causes damage to the battery. The converted power supply causes the storage battery power supply to be unstable, which may cause the battery to overheat or power loss, which is not conducive to the use of the battery. For a battery or a group of batteries, an adjusting resistor is used to adjust the motor voltage division and the current size to provide different power. This control method has large power loss on the circuit and poor adjustability. SUMMARY

[0003] The present application aims to at least solve one of the technical problems in the related art. To this end, one object of the present application is to provide an electric vehicle composite energy storage system and an energy distribution method, which solves the problems of poor speed regulation effect, large battery power loss, and large impact on battery service life.

[0004] According to the electric vehicle composite energy storage system provided by the present application, the power supply module and the charging module are connected in series, and the power supply module is connected to the motor through the power supply module and the charging module.

[0005] The power supply module includes a primary power supply unit, a secondary power supply unit, and a tertiary power supply unit. The primary power supply unit includes a lithium iron phosphate battery pack, a supercapacitor pack, a bidirectional DC / DC converter, and a brake charger. The supercapacitor pack is located at the positive and negative terminals of the lithium iron phosphate battery pack. A bidirectional DC / DC converter is located on the next segment below the supercapacitor pack at the positive and negative terminals of the lithium iron phosphate battery pack. The output of the bidirectional DC / DC converter is electrically connected to the brake charger. The secondary power supply unit includes a lithium-air battery pack, a secondary capacitor pack, and a unidirectional DC / DC converter. The lithium-air battery pack… The power supply positive and negative terminals are equipped with intermediate capacitor banks. The power supply positive and negative terminals of the lithium-air battery pack are equipped with unidirectional DC / DC converters in the next segment below the intermediate capacitor banks. The three-stage power supply unit includes a lithium battery array and unidirectional DC / DC converters. The power supply positive and negative terminals of the lithium battery array are equipped with unidirectional DC / DC converters. The positive terminal of the bidirectional DC / DC converter output and the positive terminals of the two unidirectional DC / DC converter outputs are equipped with electronically controlled switches. The positive terminal of the bidirectional DC / DC converter output and the outputs of the two unidirectional DC / DC converters are connected in parallel to supply power to the electric vehicle motor.

[0006] The charging module includes a charging control board, a primary charging circuit, a secondary charging circuit, and a tertiary charging circuit. The input terminal of the charging control board is electrically connected to the mains power. The output terminal of the charging control board has three output circuits, which are respectively electrically connected to the primary, secondary, and tertiary charging circuits. The output terminals of the primary, secondary, and tertiary charging circuits are respectively electrically connected to the independent charging tabs on the lithium iron phosphate battery pack, the lithium-air battery pack, and the lithium battery pack array. The charging control board controls the primary, secondary, and tertiary charging circuits to start charging the corresponding battery packs at intervals.

[0007] The total energy storage capacity ratio of the lithium iron phosphate battery pack, the lithium-air battery pack, and the lithium battery pack is 12:5:3.

[0008] The power supply module is controlled by an energy controller, which is electrically connected to a speed tester.

[0009] In some embodiments of the present invention, the lithium iron phosphate battery pack includes one No. 1 lithium iron phosphate battery and two No. 2 lithium iron phosphate batteries. The energy storage capacity ratio of the No. 1 lithium iron phosphate battery to the two No. 2 lithium iron phosphate batteries is 4:1:1. The No. 1 lithium iron phosphate battery and the two No. 2 lithium iron phosphate batteries are connected in parallel. An electronic control switch is provided on the positive terminal of the output terminal of the No. 1 lithium iron phosphate battery and the two No. 2 lithium iron phosphate batteries.

[0010] The lithium-air battery pack includes 2-3 lithium-air batteries connected in parallel;

[0011] The lithium battery array comprises 3-5 small lithium battery blocks, and the small lithium battery blocks are provided with electric control switches on the output positive poles and are connected in parallel.

[0012] In some other embodiments of the present application, the No. 1 lithium iron phosphate battery, the two No. 2 lithium iron phosphate batteries, the lithium air battery and each small lithium battery block are independently provided with an electric quantity monitor, and all the electric quantity monitors are electrically connected with the electric energy controller.

[0013] In some other embodiments of the present application, the super capacitor group stores energy equivalent to the power supply of the lithium iron phosphate battery group for 5-6 seconds, and the intermediate capacitor group stores energy equivalent to the power supply of the lithium air battery for 2-3 seconds.

[0014] An energy distribution method of the electric vehicle composite energy storage system, which adopts the above electric vehicle composite energy storage system for energy distribution, and the specific distribution method is as follows:

[0015] S1: when the electric vehicle starts, the electric energy controller controls the electric control switch on the output end of the bidirectional DC / DC converter to supply power, at the starting moment, the super capacitor group instantaneously releases electric energy, when the release time is 2-3 seconds, the lithium iron phosphate battery group starts to discharge and charges the super capacitor group after the voltage difference between the lithium iron phosphate battery group and the super capacitor group, and then the electric vehicle motor is supplied with power at the same time;

[0016] S2: when the electric vehicle accelerates rapidly without gear shifting, the electric energy controller controls the electric control switch on the output end of the corresponding unidirectional DC / DC converter of the lithium air battery to supply power, at the starting moment, the intermediate capacitor group instantaneously releases electric energy, after the release time is 1-2 seconds, the lithium air battery starts to discharge and charges the intermediate capacitor group after the voltage difference between the lithium air battery and the intermediate capacitor group, and then the electric vehicle motor is supplied with power at the same time, and the lithium air battery and the lithium iron phosphate battery are connected in parallel to increase the current and increase the motor power to accelerate rapidly;

[0017] S3: when the electric vehicle accelerates slowly without gear shifting, the electric energy controller controls the electric control switch on the output end of the lithium battery array to supply power, the lithium battery array and the lithium iron phosphate battery are connected in parallel to increase the current and increase the motor power to accelerate slowly;

[0018] S4: the lithium air battery independently supplies power to the electric equipment in the electric vehicle except the motor.

[0019] In some other embodiments of the present application, the lithium phosphate battery pack comprises one lithium phosphate battery No. 1 and two lithium phosphate batteries No. 2, and each of the positive poles of the output ends of the two lithium phosphate batteries No. 2 is provided with an electrically controlled switch, and the lithium phosphate battery pack has three gears for starting the electric vehicle, the first gear is started by the one lithium phosphate battery No. 1, the second gear is started by the one lithium phosphate battery No. 1 and one lithium phosphate battery No. 2, and the third gear is started by the one lithium phosphate battery No. 1 and the two lithium phosphate batteries No. 2.

[0020] In some other embodiments of the present application, each of the one lithium phosphate battery No. 1 and the two lithium phosphate batteries No. 2 is provided with an electric quantity monitor, when the electric quantity monitor detects that the electric quantity difference between the two lithium phosphate batteries No. 2 exceeds 20%, the larger one of the two lithium phosphate batteries No. 2 is preferentially started for the second gear operation, and when the electric quantity of the used lithium phosphate battery No. 2 is lower than 20% of the electric quantity of the unused lithium phosphate battery No. 2 after the second gear operation for a period of time, the other unused lithium phosphate battery No. 2 is switched for the second gear operation.

[0021] In some other embodiments of the present application, the lithium battery pack array comprises 3-5 small lithium battery blocks, and the speed of full acceleration is determined according to the number of the small lithium battery blocks started, and if the acceleration of the lithium air battery pack does not reach the acceleration requirement, the number of the small lithium battery blocks in the lithium battery pack array can be simultaneously started to assist the acceleration to the required speed.

[0022] In some other embodiments of the present application, each of the small lithium battery blocks in the lithium battery pack array is provided with an electric quantity monitor, when the slow acceleration or the assisted acceleration is started, the small lithium battery blocks are started for the acceleration according to the electric quantity from high to low, and when the electric quantity of the used small lithium battery block is lower than 20% of the electric quantity of the unused small lithium battery block after the small lithium battery block is accelerated for a period of time, the acceleration is switched.

[0023] In the present application, the lithium phosphate battery pack is used for basic operation when the electric vehicle is started, when acceleration is required, the additional electric quantity is provided by increasing the power supply of the secondary power supply unit and the tertiary power supply unit, the original lithium phosphate battery pack continues to supply power without changing the power supply, the power supply of the lithium phosphate battery pack is stable, the damage to the battery is low, the service life is long, the acceleration is more convenient and fast, and when deceleration is required, the power supply of the secondary power supply unit and / or the tertiary power supply unit is cancelled, or the gear is shifted by the lithium phosphate battery pack, and each lithium phosphate battery does not change the power supply, the service life of the battery is long, the electric loss is low, and the controllability is high. BRIEF DESCRIPTION OF DRAWINGS

[0024] The accompanying drawings are included to provide a further understanding of the application, and are incorporated in and constitute a part of this specification, illustrate embodiments of the application, and together with the description serve to explain the principles of the application, and should not be taken as limiting the application. In the drawings:

[0025] Fig. 1 A schematic diagram of a principle of a composite energy storage system for an electric vehicle is provided.

[0026] Fig. 2 A schematic diagram of battery distribution and circuit in a power supply module is provided. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application.

[0028] As Figs. 1-2 shown, the composite energy storage system for an electric vehicle provided by the application comprises a power supply module and a charging module;

[0029] The power supply module comprises a first power supply unit, a second power supply unit and a third power supply unit. The first power supply unit comprises a lithium iron phosphate battery pack, a super capacitor pack, a bidirectional DC / DC converter and a brake energy charger. The super capacitor pack is arranged on the positive and negative poles of the lithium iron phosphate battery pack. The bidirectional DC / DC converter is arranged on the next segment below the super capacitor pack on the positive and negative poles of the lithium iron phosphate battery pack. The output end of the bidirectional DC / DC converter is electrically connected with the brake energy charger. The second power supply unit comprises a lithium air battery pack, an intermediate capacitor pack and a unidirectional DC / DC converter. The intermediate capacitor pack is arranged on the positive and negative poles of the lithium air battery pack. The unidirectional DC / DC converter is arranged on the next segment below the intermediate capacitor pack on the positive and negative poles of the lithium air battery pack. The third power supply unit comprises a lithium battery pack array and a unidirectional DC / DC converter. The unidirectional DC / DC converter is arranged on the positive and negative poles of the lithium battery pack array. The positive pole of the output end of the bidirectional DC / DC converter and the positive poles of the output ends of the two unidirectional DC / DC converters are all provided with electrically controlled switches. The positive pole of the output end of the bidirectional DC / DC converter and the positive poles of the output ends of the two unidirectional DC / DC converters are connected in parallel to supply power to the motor of the electric vehicle.

[0030] The charging module comprises a charging control panel, a first-stage charging circuit, a second-stage charging circuit and a third-stage charging circuit, an input end of the charging control panel is electrically connected with commercial power, an output end of the charging control panel is provided with three-way output circuits and the three-way output circuits are electrically connected with the first-stage charging circuit, the second-stage charging circuit and the third-stage charging circuit respectively, output ends of the first-stage charging circuit, the second-stage charging circuit and the third-stage charging circuit are electrically connected with independent charging tabs on the lithium iron phosphate battery pack, the lithium air battery pack and the lithium battery pack array respectively, the charging control panel controls the start of the first-stage charging circuit, the second-stage charging circuit and the third-stage charging circuit to charge the corresponding battery pack respectively;

[0031] The total capacity ratio of the lithium iron phosphate battery pack, the lithium air battery pack and the lithium battery pack is 12:5:3;

[0032] The power supply module is controlled by an electric energy controller, and the electric energy controller is electrically connected with a speed tester.

[0033] The speed control of the electric vehicle is generally controlled by a control panel to control the power supply of the battery. Since the power supply of the battery changes when accelerating or decelerating, the battery is damaged, the service life is shortened, and the storage capacity is gradually reduced. The first-stage power supply unit is used as the main power supply, so that the electric vehicle mainly relies on the lithium iron phosphate battery pack for power supply on the road. When accelerating (at a normal speed), the lithium air battery pack provides additional power for acceleration, but the acceleration range is limited. The lithium battery pack array can be used for acceleration control.

[0034] The bidirectional DC / DC converter can be realized when braking (at this time the power supply is disconnected), and the brake energy collector is a conventional brake energy collection device. The lithium iron phosphate battery pack is temporarily charged, and the waste of automobile kinetic energy is reduced.

[0035] The super capacitor pack and the intermediate capacitor pack can protect the battery from damage caused by instantaneous power supply or voltage changes, and can provide temporary power supply buffer and protection.

[0036] The battery will be hot when charging, the energy in the battery changes, when the battery overheats, the energy loss will occur, because now the battery pack is multi-block, using fast charging, it can be full in a short time, but it requires high battery and causes great damage to the battery, sometimes, when the car is not in urgent use, slow charging is generally used, if the slow charging time is long, the battery will be in the charging state all the time, and it is relatively difficult for the internal energy to be stable. Using charging for a period of time and then resting for a period of time, waiting for the battery to charge and then stabilize for a period of time, is relatively beneficial to large-scale batteries, but if the interval charging time is long, at this time, the first, second and third power supply units are charged in intervals, for example, the first power supply unit is charged for 30 minutes, then the second power supply unit is charged for 20 minutes, and the third power supply unit is charged for 10 minutes, and the cycle charging is carried out (but the battery is not used for power supply in between), which is more beneficial to charging and prevents the battery from overheating when continuously charging.

[0037] The lithium iron phosphate battery group accounts for about 60% of the total power, mainly used for different gear electric vehicle operation, and the lithium air battery group accounts for about 25%, used for acceleration and system power equipment independent power supply. The lithium battery group is used for slow acceleration.

[0038] The lithium iron phosphate battery group includes one No. 1 lithium iron phosphate battery and two No. 2 lithium iron phosphate batteries, the storage capacity ratio of the No. 1 lithium iron phosphate battery and the two No. 2 lithium iron phosphate batteries is 4:1:1, the No. 1 lithium iron phosphate battery and the two No. 2 lithium iron phosphate batteries are connected in parallel, and an electric control switch is arranged on the positive electrode of the output end of the No. 1 lithium iron phosphate battery and the two No. 2 lithium iron phosphate batteries;

[0039] The lithium air battery group includes 2-3 lithium air batteries connected in parallel;

[0040] The lithium battery group array includes 3-5 small lithium battery blocks, and the small lithium battery blocks are provided with electric control switches on the positive electrodes of the output ends and output in parallel.

[0041] Two No. 2 lithium iron phosphate batteries are arranged for gear adjustment. Parallel connection of several gears increases several gears. The battery capacity ratio can also be adjusted or the number of No. 2 lithium iron phosphate batteries can be increased according to needs.

[0042] An electric quantity monitor is independently arranged on the No. 1 lithium iron phosphate battery, the two No. 2 lithium iron phosphate batteries, the lithium air battery group and each small lithium battery block, and all the electric quantity monitors are electrically connected with the electric energy controller. The battery can be monitored and switched in real time.

[0043] The super capacitor group stores energy equivalent to 5-6 seconds of power supply of the lithium iron phosphate battery group when supplying power; and the intermediate capacitor group stores energy equivalent to 2-3 seconds of power supply of the lithium air battery group when supplying power.

[0044] The battery directly powers at the starting moment, which is very unstable, and the battery power cannot provide enough voltage at the starting moment. Compared with the capacitor, the capacitor can provide enough voltage to start, but the voltage will gradually decrease.

[0045] An energy distribution method of an electric vehicle composite energy storage system, which adopts the above-mentioned electric vehicle composite energy storage system for energy distribution, and the specific distribution method is as follows:

[0046] S1: when the electric vehicle starts, the electric energy controller controls the electric control switch on the output end of the bidirectional DC / DC converter to supply power, at the starting moment, the super capacitor group releases electric energy instantaneously, after 2-3 seconds of release, the lithium iron phosphate battery group and the super capacitor group have a voltage difference, the lithium iron phosphate battery group will start to discharge and charge the super capacitor group, and then supply power to the electric vehicle motor at the same time;

[0047] S2: when the electric vehicle accelerates rapidly without shifting, the electric energy controller controls the electric control switch on the output end of the one-way DC / DC converter corresponding to the lithium air battery group to supply power, at the starting moment, the intermediate capacitor group releases electric energy instantaneously, after 1-2 seconds of release, the lithium air battery group and the intermediate capacitor group have a voltage difference, the lithium air battery group will start to discharge and charge the intermediate capacitor group, and then supply power to the electric vehicle motor, and the parallel connection of the lithium air battery group and the lithium iron phosphate battery group increases the current and increases the motor power to accelerate rapidly;

[0048] S3: when the electric vehicle accelerates slowly without shifting, the electric energy controller controls the electric control switch on the output end of the lithium battery group array to supply power, and the parallel connection of the lithium battery group array and the lithium iron phosphate battery group increases the current and increases the motor power to accelerate slowly;

[0049] S4: the lithium air battery group independently supplies power to the electric equipment in the electric vehicle except the motor.

[0050] The voltage after the conversion of the bidirectional DC / DC converter and the one-way DC / DC converter is the same, and the appropriate voltage can be provided according to the needs, and the control speed is controlled by the number of parallel connected batteries and the controller controls the resistance (not shown in the figure, but the resistance control reduces its function, mainly relying on the number of batteries to accelerate), after the battery is connected, the current increases, and the motor will increase the power to meet the speed requirement.

[0051] The super capacitor group and the intermediate capacitor group are set according to the corresponding battery capacity, and the battery is protected according to the needs.

[0052] When not running on the road, such as reversing into the garage, only start the lithium air battery or lithium battery array to power, to achieve low speed running reverse, or low speed forward.

[0053] The lithium iron phosphate battery includes one No. 1 lithium iron phosphate battery and two No. 2 lithium iron phosphate batteries, and an electric control switch is arranged on the positive electrode of the output end of the No. 1 lithium iron phosphate battery and the two No. 2 lithium iron phosphate batteries. The lithium iron phosphate battery group sets three gears for starting the electric vehicle, and only the No. 1 lithium iron phosphate battery is started to power as the first gear, the No. 1 lithium iron phosphate battery and a No. 2 lithium iron phosphate battery are started to power as the second gear, and the No. 1 lithium iron phosphate battery and the two No. 2 lithium iron phosphate batteries are started to power as the third gear.

[0054] The gears are mainly set by the lithium iron phosphate battery group, and the battery capacity and quantity can be increased as needed.

[0055] The No. 1 lithium iron phosphate battery and the two No. 2 lithium iron phosphate batteries are each provided with an electric quantity monitor. When the electric quantity monitor detects that the electric quantity difference between the two No. 2 lithium iron phosphate batteries exceeds 20%, the larger No. 2 lithium iron phosphate battery is preferentially started for the second gear operation. When the second gear operation is performed for a period of time, and the electric quantity of the used No. 2 lithium iron phosphate battery is lower than 20% of the electric quantity of the unused No. 2 lithium iron phosphate battery, the other unused No. 2 lithium iron phosphate battery is switched for the second gear operation.

[0056] In order to reduce the electric quantity difference between the two No. 2 lithium iron phosphate batteries and the remaining electric quantity control with the No. 1 lithium iron phosphate battery, the switching is controlled by the electric quantity monitor, and the switching is intelligent or manual.

[0057] The lithium battery array includes 3-5 small lithium battery blocks, and the full acceleration speed is determined according to the number of small lithium battery blocks started. If the lithium air battery is started for acceleration and the acceleration requirement is not reached, the number of small lithium battery blocks in the lithium battery array can be started to assist acceleration to the required speed.

[0058] The small lithium battery block has small current and can be used for micro-acceleration to achieve smooth acceleration, and the number of small lithium battery blocks can be increased to adjust the acceleration size.

[0059] Each small lithium battery block in the lithium battery array is provided with an electric quantity monitor. When slow acceleration or assistance acceleration is started, the small lithium battery blocks are started for acceleration according to the electric quantity from high to low for cooperation acceleration. When the small lithium battery blocks are accelerated for a period of time, and the electric quantity of the used small lithium battery block is lower than 20% of the electric quantity of the unused small lithium battery block, the switching for acceleration is performed.

[0060] Since the small lithium battery block has several blocks, using does not start the block according to the needs, which will cause some batteries to run out of power, and others to be in high power. The monitoring and intelligent adjustment control is used to balance the power supply.

[0061] The above merely describes the preferred embodiments of the present application, but the protection scope of the present application is not limited thereto, and any skilled person in the art can make equivalent replacements or changes within the technical range disclosed by the present application according to the technical solution and the inventive concept of the present application, which should be covered within the protection scope of the present application.

Claims

1. An electric vehicle hybrid energy storage system, characterized by: The power supply module and the charging module are included; The power supply module includes a first power supply unit, a second power supply unit and a third power supply unit, the first power supply unit includes a lithium iron phosphate battery group, a super capacitor group, a bidirectional DC / DC converter and a brake energy charger, the super capacitor group is arranged on the positive and negative power supply poles of the lithium iron phosphate battery group, the bidirectional DC / DC converter is arranged on the next segment of the super capacitor group on the positive and negative power supply poles of the lithium iron phosphate battery group, the output end of the bidirectional DC / DC converter is electrically connected with the brake energy charger, the second power supply unit includes a lithium air battery group, an intermediate capacitor group and a unidirectional DC / DC converter, the intermediate capacitor group is arranged on the positive and negative power supply poles of the lithium air battery group, the unidirectional DC / DC converter is arranged on the next segment of the intermediate capacitor group on the positive and negative power supply poles of the lithium air battery group, the third power supply unit includes a lithium battery group array and a unidirectional DC / DC converter, the unidirectional DC / DC converter is arranged on the positive and negative power supply poles of the lithium battery group array, the positive pole of the output end of the bidirectional DC / DC converter and the positive poles of the output ends of the two unidirectional DC / DC converters are all provided with electrically controlled switches, and the positive pole of the output end of the bidirectional DC / DC converter and the positive poles of the output ends of the two unidirectional DC / DC converters are connected in parallel to supply power to an electric vehicle motor; The charging module includes a charging control panel, a first charging circuit, a second charging circuit and a third charging circuit, the input end of the charging control panel is electrically connected with commercial power, the output end of the charging control panel is provided with three output circuits, and the three output circuits are respectively electrically connected with the first charging circuit, the second charging circuit and the third charging circuit, the output ends of the first charging circuit, the second charging circuit and the third charging circuit are respectively electrically connected with independent charging tabs of the lithium iron phosphate battery group, the lithium air battery group and the lithium battery group array, and the charging control panel controls the start of the first charging circuit, the second charging circuit and the third charging circuit to charge the corresponding battery group. The total storage capacity ratio of the lithium iron phosphate battery group, the lithium air battery group and the lithium battery group is 12:5:

3. The power supply module is controlled by an electric energy controller, and the electric energy controller is electrically connected with a speed tester.

2. The hybrid energy storage system of claim 1, wherein: The lithium iron phosphate battery group includes one No. 1 lithium iron phosphate battery and two No. 2 lithium iron phosphate batteries, the storage capacity ratio of the No. 1 lithium iron phosphate battery and the two No. 2 lithium iron phosphate batteries is 4:1:1, the No. 1 lithium iron phosphate battery and the two No. 2 lithium iron phosphate batteries are connected in parallel, and the positive poles of the output ends of the No. 1 lithium iron phosphate battery and the two No. 2 lithium iron phosphate batteries are all provided with an electrically controlled switch. The lithium air battery group includes 2-3 lithium air batteries connected in parallel. The lithium battery group array includes 3-5 small lithium batteries, and the positive poles of the output ends of the small lithium batteries are all provided with an electrically controlled switch and the small lithium batteries are connected in parallel.

3. The hybrid energy storage system of claim 2, wherein: An electric quantity monitor is independently arranged on the No. 1 lithium iron phosphate battery, the two No. 2 lithium iron phosphate batteries, the lithium air battery group and each small lithium battery, and all the electric quantity monitors are electrically connected with the electric energy controller.

4. The hybrid energy storage system of claim 1, wherein: The super capacitor group stores energy equivalent to 5-6 seconds of power supply of the lithium iron phosphate battery group; the intermediate capacitor group stores energy equivalent to 2-3 seconds of power supply of the lithium air battery group.

5. An energy distribution method for an electric vehicle hybrid energy storage system, characterized by: The energy distribution method of the electric vehicle composite energy storage system of any one of claims 1-4 is as follows: S1: when the electric vehicle starts, the electric energy controller controls the electric control switch on the output end of the bidirectional DC / DC converter to supply power, at the starting moment, the super capacitor group releases electric energy instantaneously, when the release time is 2-3 seconds, there is a voltage difference between the lithium iron phosphate battery group and the super capacitor group, the lithium iron phosphate battery group starts to discharge and charge the super capacitor group, and then supplies power to the electric motor of the electric vehicle at the same time; S2: when the electric vehicle accelerates rapidly without gear shifting, the electric energy controller controls the electric control switch on the output end of the unidirectional DC / DC converter corresponding to the lithium air battery group to supply power, at the starting moment, the intermediate capacitor group releases electric energy instantaneously, after 1-2 seconds, there is a voltage difference between the lithium air battery group and the intermediate capacitor group, the lithium air battery group starts to discharge and charge the intermediate capacitor group, and then supplies power to the electric motor of the electric vehicle, and the parallel connection of the lithium air battery group and the lithium iron phosphate battery group increases the current and the power supply power of the electric motor to accelerate rapidly; S3: when the electric vehicle accelerates slowly without gear shifting, the electric energy controller controls the electric control switch on the output end of the lithium battery group array to supply power, the parallel connection of the lithium battery group array and the lithium iron phosphate battery group increases the current and the power supply power of the electric motor to accelerate slowly; S4: the lithium air battery group independently supplies power to the electric devices in the electric vehicle except the electric motor.

6. The energy distribution method of claim 5, wherein: The lithium iron phosphate battery group includes one No. 1 lithium iron phosphate battery and two No. 2 lithium iron phosphate batteries, an electric control switch is arranged on the positive electrode of the output end of the No. 1 lithium iron phosphate battery and the two No. 2 lithium iron phosphate batteries, the lithium iron phosphate battery group has three gears for starting the electric vehicle, only the No. 1 lithium iron phosphate battery is started to supply power for the first gear, the No. 1 lithium iron phosphate battery and one No. 2 lithium iron phosphate battery are started to supply power for the second gear, and the No. 1 lithium iron phosphate battery and the two No. 2 lithium iron phosphate batteries are started to supply power for the third gear.

7. The energy distribution method of claim 6, wherein: The No. 1 lithium iron phosphate battery and the two No. 2 lithium iron phosphate batteries are each provided with an electric quantity monitor, when the electric quantity monitor detects that the electric quantity difference between the two No. 2 lithium iron phosphate batteries exceeds 20%, the larger No. 2 lithium iron phosphate battery is preferentially started to run in the second gear, when the No. 2 lithium iron phosphate battery runs in the second gear for a period of time, and the electric quantity of the used No. 2 lithium iron phosphate battery is lower than 20% of the electric quantity of the other unused No. 2 lithium iron phosphate battery, the other unused No. 2 lithium iron phosphate battery is switched to run in the second gear.

8. The energy distribution method of claim 5, wherein: The lithium battery group array includes 3-5 small lithium batteries, the full acceleration speed is determined according to the number of started small lithium batteries, if the lithium air battery group does not reach the acceleration requirement, the number of small lithium batteries in the lithium battery group array can be started to assist acceleration to the required speed.

9. The energy distribution method of claim 8, wherein: The small lithium battery block in the lithium battery array is provided with an electric quantity monitor, when slow acceleration or assisted acceleration is started, the small lithium battery block is started to accelerate and cooperate with acceleration according to the electric quantity from high to low, when the small lithium battery block is accelerated for a period of time, and the electric quantity of the used small lithium battery block is lower than 20% of the electric quantity of the unused small lithium battery block, switching acceleration will be carried out.

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