Electric vehicle composite energy storage system and energy distribution method

Abstract

The invention discloses a composite energy storage system for an electric vehicle. The composite energy storage system comprises a power supply module and a charging module, the power supply module comprises a first-stage power supply unit, a second-stage power supply unit and a third-stage power supply unit; the charging module comprises a charging control panel, a first-stage charging circuit, a second-stage charging circuit and a third-stage charging circuit; the total power storage capacity ratio of the lithium iron phosphate battery pack, the lithium air battery pack and the lithium battery pack is 12: 5: 3, and the distribution method comprises the following steps: S1, when the electric vehicle is started, the lithium iron phosphate battery pack starts to discharge to supply power to a motor of the electric vehicle; s2, acceleration is carried out through a lithium air battery pack and a lithium battery pack array; and S3, the lithium air battery pack independently supplies power to electric equipment except the motor in the electric automobile. According to the lithium iron phosphate battery pack, the lithium air battery pack and the lithium battery pack array are accelerated under the condition that the power supply power is not changed, the service life of the battery is long, the electric loss is low, and the controllability is high.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicle energy storage systems, and in particular to an electric vehicle composite energy storage system and an energy distribution method. Background Art

[0002] Nowadays, compared with electric vehicles, electric vehicles have 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 lithium iron phosphate batteries have high energy density, their power density cannot meet satisfactory requirements. In order to solve this problem, the common practice is to use a composite energy storage system consisting of lithium iron phosphate batteries and supercapacitors to provide energy for electric vehicles. Supercapacitors have high power density and can meet the speed requirements of electric vehicles. The composite use of lithium iron phosphate batteries can increase the service life of the battery. When the battery is powered stably, the speed of the electric vehicle is increased by the power supply of the controller, which causes great damage to the battery, because the changed power supply causes the battery power supply to be unstable, which will cause heating or power loss, which is not conducive to the use of the battery. For a battery or a group of batteries with centralized power supply, it uses an adjustable resistor to adjust the motor voltage and current size to provide different powers. In this way, the control method circuit has large power loss and poor adjustability. Summary of the invention

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

[0004] According to the present invention, a composite energy storage system for electric vehicles includes a power supply module and a charging module; 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 super capacitor pack, a bidirectional DC / DC converter and a brake charger. The super capacitor pack is provided on the positive and negative poles of the lithium iron phosphate battery pack. A bidirectional DC / DC converter is provided on the positive and negative poles of the lithium iron phosphate battery pack on the next section of the super capacitor pack. The output end of the bidirectional DC / DC converter is electrically connected to the brake charger. The secondary power supply unit includes a lithium-air battery pack, an intermediate capacitor pack and a unidirectional DC / DC converter. The lithium-air battery pack An intermediate capacitor group is provided on the positive and negative poles of the power supply of the lithium-air battery pack, and a unidirectional DC / DC converter is provided on the positive and negative poles of the power supply of the lithium-air battery pack on the next section of the intermediate capacitor group. The three-level power supply unit includes a lithium battery pack array and a unidirectional DC / DC converter. A unidirectional DC / DC converter is provided on the positive and negative poles of the power supply of the lithium battery pack array, and an electric control switch is provided on 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. The positive pole of the output end of the bidirectional DC / DC converter and the output ends of the two unidirectional DC / DC converters are connected in parallel to supply power to the electric vehicle motor; The charging module includes a charging control board, a primary charging circuit, a secondary charging circuit and a tertiary charging circuit. The input end of the charging control board is electrically connected to the mains. The output end of the charging control board is provided with three output circuits and the three output circuits are electrically connected to the primary charging circuit, the secondary charging circuit and the tertiary charging circuit respectively. The output ends of the primary charging circuit, the secondary charging circuit and the tertiary charging circuit are electrically connected to the independent charging poles on the lithium iron phosphate battery pack, the lithium air battery pack and the lithium battery pack array respectively. The charging control board controls the primary charging circuit, the secondary charging circuit and the tertiary charging circuit at intervals to start charging the corresponding battery packs. The total storage capacity ratio of the lithium iron phosphate battery pack, the lithium air battery pack and the lithium battery pack is 12:5:3; The power supply module is controlled by an electric energy controller, and the electric energy controller is electrically connected to a speed tester.

[0005] In some embodiments of the present invention, the lithium iron phosphate battery pack includes a 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 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, and an electric control switch is provided 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-air battery pack comprises 2-3 lithium-air batteries connected in parallel; The lithium battery array comprises 3-5 small lithium battery blocks, and the plurality of small lithium battery blocks are provided with electric control switches on the positive electrodes of the output ends, and the plurality of small lithium battery blocks are connected in parallel for output.

[0006] In other embodiments of the present invention, the No. 1 lithium iron phosphate battery, the two No. 2 lithium iron phosphate batteries, the lithium-air battery pack and each small lithium battery block are independently provided with a power monitor, and all of the power monitors are electrically connected to the power controller.

[0007] In other embodiments of the present invention, the energy storage capacity of the supercapacitor group is equivalent to the power supply capacity of the lithium iron phosphate battery group for 5-6 seconds; the energy storage capacity of the intermediate capacitor group is equivalent to the power supply capacity of the lithium air battery group for 2-3 seconds.

[0008] An energy distribution method of an electric vehicle composite energy storage system, using the electric vehicle composite energy storage system to distribute energy, the specific distribution method is as follows: S1: When the electric vehicle starts, the electric energy controller controls the electric control switch at the output end of the bidirectional DC / DC converter to turn off the power supply. At the moment of starting, the supercapacitor group releases electric energy instantly. After 2-3 seconds of release, there is a voltage difference between the lithium iron phosphate battery group and the supercapacitor group. The lithium iron phosphate battery group will start to discharge and charge the supercapacitor group, and then supply power to the electric vehicle motor at the same time; S2: When the electric vehicle is rapidly accelerated without shifting gears, 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 pack to turn off the power supply. At the moment of starting, the intermediate capacitor group instantly releases electric energy. After 1-2 seconds of release, there is a voltage difference between the lithium-air battery pack and the intermediate capacitor group. The lithium-air battery pack will start to discharge and charge the intermediate capacitor group, and then supply power to the electric vehicle motor at the same time. After the lithium-air battery pack is connected in parallel with the lithium iron phosphate battery pack, the current is increased, so that the motor power supply power is increased to perform rapid acceleration; S3: When the electric vehicle is performing slow acceleration without shifting gears, the electric energy controller controls the electric control switch at the output end of the lithium battery array to turn off the power supply, and the lithium battery array is connected in parallel with the lithium iron phosphate battery pack to increase the current so that the motor power supply is increased to perform slow acceleration; S4: The lithium-air battery pack independently supplies power to electrical equipment other than the motor in the electric vehicle.

[0009] In some other embodiments of the present invention, the lithium iron phosphate battery pack includes a No. 1 lithium iron phosphate battery and two No. 2 lithium iron phosphate batteries, and an electric control switch is provided on the positive poles of the output ends of the No. 1 lithium iron phosphate battery and the two No. 2 lithium iron phosphate batteries. The lithium iron phosphate battery pack sets three gears for starting the electric vehicle. Starting only the No. 1 lithium iron phosphate battery for power supply is the first gear, starting the No. 1 lithium iron phosphate battery and a No. 2 lithium iron phosphate battery for power supply at the same time is the second gear, and starting the No. 1 lithium iron phosphate battery and two No. 2 lithium iron phosphate batteries for power supply at the same time is the third gear.

[0010] In some other embodiments of the present invention, the No. 1 lithium iron phosphate battery and the two No. 2 lithium iron phosphate batteries are all provided with a power monitor. When the power monitor detects that the power difference between the two No. 2 lithium iron phosphate batteries exceeds 20%, the larger No. 2 lithium iron phosphate battery is preferentially started to operate in the second gear. After operating in the second gear for a period of time, if the power in the used No. 2 lithium iron phosphate battery is lower than 20% of the power of the other unused No. 2 lithium iron phosphate battery, the other unused No. 2 lithium iron phosphate battery will be switched to operate in the second gear.

[0011] In other embodiments of the present invention, the lithium battery array includes 3-5 small lithium battery blocks, and the full acceleration speed is determined by the number of small lithium battery blocks started. If starting the lithium-air battery pack for acceleration does not meet the acceleration requirements, the number of small lithium battery blocks in the lithium battery array can also be started at the same time to assist in accelerating to the required speed.

[0012] In some other embodiments of the present invention, a power monitor is provided on each small lithium battery block in the lithium battery array. When slow acceleration or assisted acceleration is started, the small lithium battery block is started to accelerate and the acceleration is coordinated from high to low according to the power. After the small lithium battery block accelerates for a period of time, when the power of the used small lithium battery block is lower than 20% of the power of the unused small lithium battery block, the acceleration will be switched.

[0013] In the present invention, when the electric vehicle is started, the lithium iron phosphate battery pack is used for basic operation. When acceleration is required, the secondary power supply unit and the tertiary power supply unit are added to provide additional power for acceleration. The original lithium iron phosphate battery pack will continue to supply power without changing the power supply, so that the lithium iron phosphate battery pack provides stable power supply, less damage to the battery, longer service life, and more convenient and faster acceleration. When decelerating, the power supply of the secondary power supply unit and / or the tertiary power supply unit is canceled, or the lithium iron phosphate battery pack is used to shift gears. The power supply power of each lithium iron phosphate battery does not change, the battery has a long service life, low power loss, and high controllability. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings: Figure 1 This is a schematic diagram of the principle of a composite energy storage system for electric vehicles proposed by the present invention.

[0015] Figure 2 This is a schematic diagram of the battery distribution and circuit in the power supply module proposed by the present invention. DETAILED DESCRIPTION

[0016] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0017] like Figure 1-2 As shown, the present invention proposes an electric vehicle composite energy storage system, including a power supply module and a charging module; 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 super capacitor pack, a bidirectional DC / DC converter and a brake charger. The super capacitor pack is provided on the positive and negative poles of the lithium iron phosphate battery pack. A bidirectional DC / DC converter is provided on the positive and negative poles of the lithium iron phosphate battery pack on the next section of the super capacitor pack. The output end of the bidirectional DC / DC converter is electrically connected to the brake charger. The secondary power supply unit includes a lithium-air battery pack, an intermediate capacitor pack and a unidirectional DC / DC converter. The lithium-air battery pack An intermediate capacitor group is provided on the positive and negative poles of the power supply of the lithium-air battery pack, and a unidirectional DC / DC converter is provided on the positive and negative poles of the power supply of the lithium-air battery pack on the next section of the intermediate capacitor group. The three-level power supply unit includes a lithium battery pack array and a unidirectional DC / DC converter. A unidirectional DC / DC converter is provided on the positive and negative poles of the power supply of the lithium battery pack array, and an electric control switch is provided on 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. The positive pole of the output end of the bidirectional DC / DC converter and the output ends of the two unidirectional DC / DC converters are connected in parallel to supply power to the electric vehicle motor; The charging module includes a charging control board, a primary charging circuit, a secondary charging circuit and a tertiary charging circuit. The input end of the charging control board is electrically connected to the mains. The output end of the charging control board is provided with three output circuits and the three output circuits are electrically connected to the primary charging circuit, the secondary charging circuit and the tertiary charging circuit respectively. The output ends of the primary charging circuit, the secondary charging circuit and the tertiary charging circuit are electrically connected to the independent charging poles on the lithium iron phosphate battery pack, the lithium air battery pack and the lithium battery pack array respectively. The charging control board controls the primary charging circuit, the secondary charging circuit and the tertiary charging circuit at intervals to start charging the corresponding battery packs. The total storage capacity ratio of the lithium iron phosphate battery pack, the lithium air battery pack and the lithium battery pack is 12:5:3; The power supply module is controlled by an electric energy controller, and the electric energy controller is electrically connected to a speed tester.

[0018] The speed control of electric vehicles is generally carried out by controlling the battery power supply through the control panel. When the battery is accelerated or reduced, the change of power supply damages the battery, shortens its life and gradually reduces its storage capacity. The primary power supply unit is used as the main power supply, so that electric vehicles run on the road mainly relying on the main power supply module of the lithium iron phosphate battery pack. When accelerating (accelerating at normal speed), the lithium-air battery pack provides additional power for acceleration, but the acceleration range is within a certain range and must meet the required acceleration requirements before starting, otherwise it will exceed the acceleration requirements. Therefore, a lithium battery pack array with more refined acceleration can also be used for acceleration control.

[0019] The bidirectional DC / DC converter can be used to briefly charge the lithium iron phosphate battery pack when braking (the power supply is disconnected at this time), while the brake charger is a conventional brake energy collection device, which can at least reduce the waste of vehicle kinetic energy.

[0020] Supercapacitors and intermediate capacitors can protect batteries from damage caused by instantaneous power supply or the impact of lithium batteries when voltage changes, and can provide short-term power supply buffering and protection.

[0021] The battery will get hot when charging, and the energy in the battery is changing. When the battery is overheated, it will cause energy loss. Since there are multiple battery packs now, fast charging can be fully charged in a short time, but it has high requirements for the battery and causes great damage to the battery. Sometimes, when the car is not in a hurry, slow charging is generally used. If the slow charging time is long, the battery will always be in a charging state, and it is relatively difficult to stabilize the internal power. It is relatively beneficial for large batteries to charge for a period of time and then rest for a period of time, waiting for the battery to stabilize for a period of time after charging, but if the interval charging takes a long time, at this time, since the three groups of primary power supply units, secondary power supply units and tertiary power supply units are charged at intervals, for example, the primary power supply unit is charged for 30 minutes, and then the secondary power supply unit is charged for 20 minutes, and the tertiary power supply unit is charged for 10 minutes. Such a cycle charging (but no battery power supply is used in the middle) is more conducive to charging and prevents serious battery heating problems during continuous charging.

[0022] The lithium iron phosphate battery pack accounts for about 60% of the total power, which is mainly used for the operation of electric vehicles in different gears, while the lithium air battery pack accounts for about 25%, which is used for acceleration and independent power supply of system power equipment. The lithium battery pack is used for slow acceleration.

[0023] The lithium iron phosphate battery pack includes a 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 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, and an electric control switch is provided on the positive electrodes of the output ends of the No. 1 lithium iron phosphate battery and the two No. 2 lithium iron phosphate batteries; The lithium-air battery pack comprises 2-3 lithium-air batteries connected in parallel; The lithium battery array comprises 3-5 small lithium battery blocks, and the plurality of small lithium battery blocks are provided with electric control switches on the positive electrodes of the output ends, and the plurality of small lithium battery blocks are connected in parallel for output.

[0024] Two No. 2 lithium iron phosphate batteries are set up for gear adjustment. Connecting several gears in parallel will increase the number of gears. The battery capacity ratio can also be adjusted as needed, or the number of No. 2 lithium iron phosphate batteries can be increased.

[0025] The No. 1 lithium iron phosphate battery, two No. 2 lithium iron phosphate batteries, the lithium-air battery pack, and each small lithium battery block are independently provided with a power monitor, and all the power monitors are electrically connected to the power controller, so that the power supply battery can be monitored and switched in real time.

[0026] The energy storage capacity of the supercapacitor group is equivalent to the power supply capacity of the lithium iron phosphate battery group for 5-6 seconds; the energy storage capacity of the intermediate capacitor group is equivalent to the power supply capacity of the lithium air battery group for 2-3 seconds.

[0027] At the moment of starting, direct battery power supply is very unstable, and battery power supply cannot provide enough voltage at the moment of starting. Compared with capacitors, they release quickly and can provide enough voltage to start instantly, but the disadvantage is that the voltage will gradually become lower.

[0028] An energy distribution method of an electric vehicle composite energy storage system, using the electric vehicle composite energy storage system to distribute energy, the specific distribution method is as follows: S1: When the electric vehicle starts, the electric energy controller controls the electric control switch at the output end of the bidirectional DC / DC converter to turn off the power supply. At the moment of starting, the supercapacitor group releases electric energy instantly. After 2-3 seconds of release, there is a voltage difference between the lithium iron phosphate battery group and the supercapacitor group. The lithium iron phosphate battery group will start to discharge and charge the supercapacitor group, and then supply power to the electric vehicle motor at the same time; S2: When the electric vehicle is rapidly accelerated without shifting gears, 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 pack to turn off the power supply. At the moment of starting, the intermediate capacitor group instantly releases electric energy. After 1-2 seconds of release, there is a voltage difference between the lithium-air battery pack and the intermediate capacitor group. The lithium-air battery pack will start to discharge and charge the intermediate capacitor group, and then supply power to the electric vehicle motor at the same time. After the lithium-air battery pack is connected in parallel with the lithium iron phosphate battery pack, the current is increased, so that the motor power supply power is increased to perform rapid acceleration; S3: When the electric vehicle is performing slow acceleration without shifting gears, the electric energy controller controls the electric control switch at the output end of the lithium battery array to turn off the power supply, and the lithium battery array is connected in parallel with the lithium iron phosphate battery pack to increase the current so that the motor power supply is increased to perform slow acceleration; S4: The lithium-air battery pack independently supplies power to electrical equipment other than the motor in the electric vehicle.

[0029] The voltage after conversion by the bidirectional DC / DC converter is the same as that by the unidirectional DC / DC converter, and the appropriate voltage can be provided as required. The speed is controlled by the number of batteries in parallel and the resistance controlled by the controller (not shown in the figure, but the resistance control reduces its function, and the acceleration is mainly achieved by the number of batteries connected). After the batteries are connected, the current increases, and the motor will increase its power to meet the speed increase requirements.

[0030] The size of the supercapacitor group and the intermediate capacitor group is set according to the corresponding battery capacity to protect the battery as needed.

[0031] When not operating on the road, such as reversing into a garage, only the lithium-air battery pack or the lithium battery array can be started for power supply to achieve low-speed reversing or low-speed forward driving.

[0032] The lithium iron phosphate battery pack includes a No. 1 lithium iron phosphate battery and two No. 2 lithium iron phosphate batteries. An electric control switch is provided on the positive poles of the output ends of the No. 1 lithium iron phosphate battery and the two No. 2 lithium iron phosphate batteries. The lithium iron phosphate battery pack sets three gears for starting the electric vehicle. Starting only the No. 1 lithium iron phosphate battery for power supply is the first gear, starting the No. 1 lithium iron phosphate battery and a No. 2 lithium iron phosphate battery for power supply at the same time is the second gear, and starting the No. 1 lithium iron phosphate battery and two No. 2 lithium iron phosphate batteries for power supply at the same time is the third gear.

[0033] The gear setting mainly relies on the lithium iron phosphate battery pack, and the battery capacity and quantity can be increased as needed.

[0034] The No. 1 lithium iron phosphate battery and the two No. 2 lithium iron phosphate batteries are all equipped with a power monitor. When the power monitor detects that the power difference between the two No. 2 lithium iron phosphate batteries exceeds 20%, the larger No. 2 lithium iron phosphate battery is started first to operate in the second gear. After running in the second gear for a period of time, if the power in the used No. 2 lithium iron phosphate battery is lower than 20% of the power of the other unused No. 2 lithium iron phosphate battery, the other unused No. 2 lithium iron phosphate battery will be switched to operate in the second gear.

[0035] In order to reduce the power difference between the two No. 2 lithium iron phosphate batteries and control the remaining power of the No. 1 lithium iron phosphate battery, the power monitor is used to control the required switching, intelligent switching or manual switching.

[0036] The lithium battery array includes 3-5 small lithium battery blocks. The full acceleration speed is determined by the number of small lithium battery blocks started. If starting the lithium-air battery pack for acceleration does not meet the acceleration requirements, the number of small lithium battery blocks in the lithium battery array can also be started at the same time to assist in accelerating to the required speed.

[0037] Small lithium battery blocks have a small current and can perform micro-acceleration to achieve smooth acceleration. The acceleration can be adjusted by adding more blocks as needed.

[0038] A power monitor is provided on each small lithium battery block in the lithium battery array. When slow acceleration or assisted acceleration is started, the small lithium battery block is started to accelerate and the acceleration is coordinated from high to low power. After the small lithium battery block accelerates for a period of time, when the power of the used small lithium battery block is 20% lower than the power of the unused small lithium battery block, the acceleration will be switched.

[0039] Since there are several small lithium battery packs, if you don't start one according to the need, some batteries will run out of power while others are still at high power. Use monitoring and intelligent adjustment control to balance the power supply.

[0040] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A composite energy storage system for electric vehicles, characterized in that: Including power supply module and charging module; 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 super capacitor pack, a bidirectional DC / DC converter and a brake charger. The super capacitor pack is provided on the positive and negative poles of the lithium iron phosphate battery pack. A bidirectional DC / DC converter is provided on the positive and negative poles of the lithium iron phosphate battery pack on the next section of the super capacitor pack. The output end of the bidirectional DC / DC converter is electrically connected to the brake charger. The secondary power supply unit includes a lithium-air battery pack, an intermediate capacitor pack and a unidirectional DC / DC converter. The lithium-air battery pack An intermediate capacitor group is provided on the positive and negative poles of the power supply of the lithium-air battery pack, and a unidirectional DC / DC converter is provided on the positive and negative poles of the power supply of the lithium-air battery pack on the next section of the intermediate capacitor group. The three-level power supply unit includes a lithium battery pack array and a unidirectional DC / DC converter. A unidirectional DC / DC converter is provided on the positive and negative poles of the power supply of the lithium battery pack array, and an electric control switch is provided on 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. The positive pole of the output end of the bidirectional DC / DC converter and the output ends of the two unidirectional DC / DC converters are connected in parallel to supply power to the electric vehicle motor; The charging module includes a charging control board, a primary charging circuit, a secondary charging circuit and a tertiary charging circuit. The input end of the charging control board is electrically connected to the mains. The output end of the charging control board is provided with three output circuits and the three output circuits are electrically connected to the primary charging circuit, the secondary charging circuit and the tertiary charging circuit respectively. The output ends of the primary charging circuit, the secondary charging circuit and the tertiary charging circuit are electrically connected to the independent charging poles on the lithium iron phosphate battery pack, the lithium air battery pack and the lithium battery pack array respectively. The charging control board controls the primary charging circuit, the secondary charging circuit and the tertiary charging circuit at intervals to start charging the corresponding battery packs. The total storage capacity ratio of the lithium iron phosphate battery pack, the lithium air battery pack and the lithium battery pack is 12:5:3; The power supply module is controlled by an electric energy controller, and the electric energy controller is electrically connected to a speed tester.

2. The electric vehicle composite energy storage system according to claim 1, characterized in that: The lithium iron phosphate battery pack includes a 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 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, and an electric control switch is provided on the positive electrodes of the output ends of the No. 1 lithium iron phosphate battery and the two No. 2 lithium iron phosphate batteries; The lithium-air battery pack comprises 2-3 lithium-air batteries connected in parallel; The lithium battery array comprises 3-5 small lithium battery blocks, and the plurality of small lithium battery blocks are provided with electric control switches on the positive electrodes of the output ends, and the plurality of small lithium battery blocks are connected in parallel for output.

3. The electric vehicle composite energy storage system according to claim 2, characterized in that: The No. 1 lithium iron phosphate battery, the two No. 2 lithium iron phosphate batteries, the lithium-air battery pack and each small lithium battery block are independently provided with a power monitor, and all of the power monitors are electrically connected to the power controller.

4. The electric vehicle composite energy storage system according to claim 1, characterized in that: The energy storage capacity of the supercapacitor group is equivalent to the power supply capacity of the lithium iron phosphate battery group for 5-6 seconds; the energy storage capacity of the intermediate capacitor group is equivalent to the power supply capacity of the lithium air battery group for 2-3 seconds.

5. An energy distribution method for a composite energy storage system of an electric vehicle, characterized in that: The electric vehicle composite energy storage system according to any one of claims 1 to 4 is used for energy distribution, and the specific distribution method is as follows: S1: When the electric vehicle starts, the electric energy controller controls the electric control switch at the output end of the bidirectional DC / DC converter to turn off the power supply. At the moment of starting, the supercapacitor group releases electric energy instantly. After 2-3 seconds of release, there is a voltage difference between the lithium iron phosphate battery group and the supercapacitor group. The lithium iron phosphate battery group will start to discharge and charge the supercapacitor group, and then supply power to the electric vehicle motor at the same time; S2: When the electric vehicle is rapidly accelerated without shifting gears, 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 pack to turn off the power supply. At the moment of starting, the intermediate capacitor group instantly releases electric energy. After 1-2 seconds of release, there is a voltage difference between the lithium-air battery pack and the intermediate capacitor group. The lithium-air battery pack will start to discharge and charge the intermediate capacitor group, and then supply power to the electric vehicle motor at the same time. After the lithium-air battery pack is connected in parallel with the lithium iron phosphate battery pack, the current is increased, so that the motor power supply power is increased to perform rapid acceleration; S3: When the electric vehicle is performing slow acceleration without shifting gears, the electric energy controller controls the electric control switch at the output end of the lithium battery array to turn off the power supply, and the lithium battery array is connected in parallel with the lithium iron phosphate battery pack to increase the current so that the motor power supply is increased to perform slow acceleration; S4: The lithium-air battery pack independently supplies power to electrical equipment other than the motor in the electric vehicle.

6. The energy distribution method of the electric vehicle composite energy storage system according to claim 5, characterized in that: The lithium iron phosphate battery pack includes a No. 1 lithium iron phosphate battery and two No. 2 lithium iron phosphate batteries. An electric control switch is provided on the positive poles of the output ends of the No. 1 lithium iron phosphate battery and the two No. 2 lithium iron phosphate batteries. The lithium iron phosphate battery pack sets three gears for starting the electric vehicle. Starting only the No. 1 lithium iron phosphate battery for power supply is the first gear, starting the No. 1 lithium iron phosphate battery and a No. 2 lithium iron phosphate battery for power supply at the same time is the second gear, and starting the No. 1 lithium iron phosphate battery and two No. 2 lithium iron phosphate batteries for power supply at the same time is the third gear.

7. The energy distribution method of the electric vehicle composite energy storage system according to claim 6, characterized in that: The No. 1 lithium iron phosphate battery and the two No. 2 lithium iron phosphate batteries are all equipped with a power monitor. When the power monitor detects that the power difference between the two No. 2 lithium iron phosphate batteries exceeds 20%, the larger No. 2 lithium iron phosphate battery is started first to operate in the second gear. After running in the second gear for a period of time, if the power in the used No. 2 lithium iron phosphate battery is lower than 20% of the power of the other unused No. 2 lithium iron phosphate battery, the other unused No. 2 lithium iron phosphate battery will be switched to operate in the second gear.

8. The energy distribution method of the electric vehicle composite energy storage system according to claim 5, characterized in that: The lithium battery array includes 3-5 small lithium battery blocks. The full acceleration speed is determined by the number of small lithium battery blocks started. If starting the lithium-air battery pack for acceleration does not meet the acceleration requirements, the number of small lithium battery blocks in the lithium battery array can also be started at the same time to assist in accelerating to the required speed.

9. The energy distribution method of the electric vehicle composite energy storage system according to claim 8, characterized in that: A power monitor is provided on each small lithium battery block in the lithium battery array. When slow acceleration or assisted acceleration is started, the small lithium battery block is started to accelerate and the acceleration is coordinated from high to low power. After the small lithium battery block accelerates for a period of time, when the power of the used small lithium battery block is 20% lower than the power of the unused small lithium battery block, the acceleration will be switched.

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