WO2023128778A1 - Mobile device for charging electric vehicles - Google Patents

Abstract

The invention relates to the field of electrical engineering, and more particularly to charging devices, and can be used for charging electric vehicle batteries. A mobile device for charging electric vehicles comprises: a fuel storage tank; an engine connected thereto for powering a generator that is connected to a rechargeable battery pack equipped with a balancing means; and a means for charging electric vehicles, wherein said means for charging electric vehicles is connected to the rechargeable battery pack and to the generator via a charge balancing unit, wherein said charge balancing unit is designed to be capable of balancing a flow of electrical energy from the generator and/or from the rechargeable battery pack according to information transmitted from the means for charging electric vehicles and from the balancing means of the rechargeable battery pack, the charge balancing unit being connected to an engine control unit to allow the transmission of control commands. The technical result consists in making it possible for two sources of current to operate on a single direct current bus under continuous load balancing conditions, improving charging power, speed and duration, and improving charging efficiency as a whole.

Description

MOBILE DEVICE FOR CHARGING ELECTRIC VEHICLES

FIELD OF TECHNOLOGY

The invention relates to the field of electrical engineering, namely to chargers, and can be used to charge batteries of electric vehicles.

BACKGROUND OF THE INVENTION

The prior art mobile charging station for electric vehicles, described in the document CN206195367U, publ. 05/24/2017. A well-known mobile charging station for electric vehicles includes a mobile charger, a natural gas power generation system, a thermal energy storage system, a storage battery system, a charging system, and so on.

The disadvantage of this technical solution is the low efficiency of battery use, the complexity of the operation of two different current sources on one DC bus, one of which is a battery, which results in low speed, duration and charging power.

The claimed invention eliminates these disadvantages and allows to achieve the claimed technical result.

DISCLOSURE OF THE INVENTION

The technical problem that the proposed solution solves is the creation of a mobile device for charging electric vehicles, which has the ability to operate two current sources on one DC bus in a constant mode of balancing with respect to the load, having at the same time a high speed, duration and charging power.

The technical result consists in enabling the operation of two current sources on one DC bus in a constant mode of balancing with respect to the load, increasing the power, speed and duration of charging, and increasing the efficiency of charging in general.

To solve the problem with the achievement of the claimed technical result, a mobile device for charging electric vehicles contains a tank for storing fuel, an engine connected to it, leading to operating a generator connected to a battery pack provided with a balancing means, an electric vehicle charging means, wherein the electric vehicle charging means is connected to the battery pack and the generator through a charge balancing unit, the charge balancing unit being configured to balance the flow of electrical energy from the generator and/or a battery pack depending on the information transmitted from the electric vehicle charging means and the battery pack balancing means, wherein the charge balancing unit is connected to the engine control unit with the possibility of transmitting control commands.

In addition, the mobile device is mounted on a truck chassis.

In addition, the engine is a gas piston engine.

In addition, the generator is a DC generator.

In addition, the generator with the engine are installed on the same frame.

In addition, the fuel storage tank is a gas mixture storage tank.

In addition, the fuel storage tank is designed as two separate pressure vessels, where one is located inside the other in a stainless steel casing with a high level of insulation.

In addition, the fuel storage tank is equipped with a vent plug to safely vent excess pressure.

In addition, liquefied natural gas or a mixture of liquefied natural gas and hydrogen is used as fuel for the engine.

In addition, the mobile device further comprises a heat recovery system including a heat exchanger.

In addition, the heat exchanger is installed outside the casing of the fuel tank, connected to the engine water jacket by means of flexible hoses and configured to receive heat from the engine cooling system.

In addition, the battery pack consists of modular racks mounted on the bottom of the chassis frame that house the batteries.

In addition, the means for balancing the battery pack includes balancers, each of which is located in its own battery, and which are connected to each other through an independent galvanically isolated line to make it possible to equalize the voltage of series-connected batteries when charging them with a common voltage.

In addition, each battery in the battery pack is additionally equipped with a microprocessor-controlled Smart BMS.

In addition, the mobile device is designed to charge electric vehicles with direct current of the CCS and ChaDeMo standards. In addition, the mobile device is further configured to operate through a mobile application that provides users with the ability to reserve a time and place for charging the electric vehicle, as well as the possibility of a contactless payment method for charging the electric vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig.1 is a diagram of a mobile device for charging electric vehicles;

2 is a diagram of power distribution (balancing) of a mobile device for charging electric vehicles.

IMPLEMENTATION OF THE INVENTION

The mobile electric vehicle charging device comprises a fuel storage tank 1 connected to the tank 1, an engine 7 driving a generator 8 connected to a battery pack 9 provided with a balancing means, an electric vehicle charging means.

The means for charging electric vehicles is connected to the battery pack 9 and the generator 8 through the charge balancing unit, and the charge balancing unit is configured to balance the flow of electrical energy from the generator 8 and/or the battery pack 9 depending on the information transmitted from the electric vehicle charging means. means and means for balancing the battery pack, wherein the charge balancing unit is connected to the engine control unit with the possibility of transmitting control commands.

The engine may be a gas piston engine.

The control unit 5 of the charger ensures the coordination of the parameters of the charging session with the electric vehicle, for example, according to the CCS protocol, the coordination of the parameters of the charging process of the internal batteries, and the balancing of the system during the operation of the device itself.

The fuel storage tank may be a cryogenic tank (cylinder) for storing a gas mixture or another, for example, LNG and/or hydrogen. The tank can be made in the form of two separate pressure vessels, where one is located inside the other in a stainless steel casing with a high level of insulation. The working pressure in the tank is 10 bar. The internal capacity of the cryogenic fuel tank is used to store cryogenic LNG and is wrapped with multiple layers of thermal insulation material (over-insulation). In the event of an internal leak into an external vessel, the discharge the plug will open and release excess pressure in a safe way. In the event of an external depressurization of the space between the vessels and loss of vacuum, uncharacteristic moisture or frost will appear on the external vessel (the presence of frost or condensate at the sealed end of the tank is normal). The volume of the cryogenic tank allows you to store up to 500 liters of liquefied natural gas, providing 20 hours of continuous operation of the generator or 20 discharge-charge cycles, 20 charging sessions of 20-30 minutes each.

The engine control system 4 can ensure stable starting and operation of the engine over the entire range of operating temperatures. Also, this system can control the composition of the flue gases, adjusting the dosage, to achieve optimal performance. The engine control system 4 is interconnected with the engine 7, the fuel tank and the control unit 5 of the mobile charger.

The means for charging electric vehicles includes DC-DC converters 10 and a charging gun 11.

The generator can be a three-phase synchronous generator, with or without a controlled rectifier, or a DC generator. The generator can be mounted on the same frame as the engine.

Also, the device may additionally contain a standard reducer 3, a heat recovery system (gas heater 2, radiator 6), including a heat exchanger (evaporator) designed to evaporate liquid cryogenic fuel and supply it to the engine in the form of heated gas. The heat exchanger can be installed outside the fuel tank casing, connected to the engine water jacket with flexible hoses, and thus can receive heat from the engine cooling system.

The battery pack may consist of modular racks, in which batteries are placed, the charge in them is controlled using a charge balancing tool (special devices - balancers). Each balancer is placed in its own battery. The balancer allows equalization of the charge inside the battery module. All balancers are connected to each other through an independent galvanically isolated line for the possibility of equalizing the voltage of series-connected batteries when charging them with a common voltage (current).

In addition, each battery (battery module) of the battery pack can be equipped with a microprocessor-controlled Smart BMS. Smart BMS counts the incoming and outgoing energy, measures the temperature of the battery cells, the power current of the entire system, the voltage, as well as the voltage on each individual cell.

The mobile device combines the functions of generating, storing and distributing energy at different stages of charging electric vehicles. The device can be mounted on the chassis of a truck with gas, electric or any other drive.

This design is driven by the need to generate enough power so that the charging process of an electric vehicle takes as little time as possible. In addition, this design gives an advantage in terms of noise level, and also allows the engine to operate in the most optimal modes.

This solution allows you to charge electric vehicles with DC power up to 250 kW and output voltage from 400 to 800 V. During the movement of the mobile charger from client to client, charge is accumulated in the energy storage system (internal battery). The controllers determine at what point additional power is required and it is advisable to start the electrical installation.

The mobile charger is designed to charge electric vehicles with direct current of the CCS and ChaDeMo standard, the battery of an electric vehicle can be charged in 5 minutes per 100 km of run. A mobile charger can be a unit with a total capacity of 120 kW (250 kW), operate continuously for up to 20 hours, generating up to 1200 kWh (without refueling), which is equivalent to 7500 km of run, CO2 emission per 100 km is no more than 7 kg. (a diesel car emits 2.6 kg/liter which, with an urban consumption of 7-8 liters of fuel, is 20 kg of carbon dioxide (CO2) per 100 km).

The mobile device can be called through a mobile application that allows users to reserve a time and place to charge an electric vehicle, as well as use a contactless payment method.

The principle of operation of the charger is as follows. As the charger moves around the city, the generator set generates energy by consuming fuel, such as liquefied natural gas. Energy is stored in batteries. It takes about 30 minutes to fully charge its own batteries. Upon arrival at the site, the installation is connected to the electric vehicle, the charging process begins. The flow of energy from the generator is redirected to the electric vehicle. Upon reaching the maximum power, the unit begins to discharge its own batteries, while providing additional power accumulated before.

At the end of the charging session, the cycle repeats, the generator switches to the mode of charging the internal batteries.

One of the advantages and differences from the solutions known from the prior art is the possibility of distributing (balancing) the power of a mobile charger from a generator and / or a battery pack, depending on the information transmitted from the electric vehicle charging means and the balancing means of the battery pack, where the balancing unit charge is connected to the engine control unit with the possibility of transmitting control commands. The problem of the operation of two current sources, one of which is a battery, on one DC bus is in the constant mode of balancing the two sources with respect to the load. In this case, the load is a charging car that draws power limited by our generator and battery sources. If the generator has a relatively constant power, then for the battery this characteristic is variable and varies depending on the state of charge, temperature, and the level of degradation of the battery. The whole system is in constant process of current regulation according to input parameters.

The essence of balancing comes down to calculating the allowable power of the charging station based on the available power sources, taking into account the limitations for each of them.

For example, in a simple case, when charging one battery 9 with a DC generator 8 (Fig. 2), the generator regulator needs to set the maximum charging current setting for this battery, at the same time it is necessary to take into account the temperature of the battery and its current voltage. If the maximum battery voltage is exceeded, the generator regulator has a voltage limiting function. In case of low battery temperature, system 5 can also limit the current and turn on the battery heating.

The case of battery discharge can also be attributed to a simple one, in which restrictions are imposed on the discharge current based on the degree of battery discharge and is monitored by its voltage under load, that is, the system monitors the battery voltage and, in case of a drawdown below the minimum, reduces the load, limiting the available power for charging 10 electric car.

At the time of peak power, when both the battery 9 and the generator set 8 are involved, all the above restrictions are imposed. When starting with the generator stopped, battery power is available, the generator starts based on the calculated maximum power, remaining battery capacity or bus voltage sag. When starting, the system increases the generator voltage until the current stabilizes with the setting. The current setting for the generator in such cases should be calculated based on the power to charge the battery and the load to charge the electric vehicle being charged. In the process of reaching maximum power, the system constantly monitors the voltage on the bus, limiting the power of the generator in case of excess. At the same time, the system increases the load power - the voltage drops, the generator power increases again. The process continues until reaching full capacity. With a sufficiently large load, the restrictions on the upper voltage limit become irrelevant due to the drop in battery voltage to the midpoint within the upper and lower limits, voltage fluctuations are insignificant. At the end of the battery discharge, the output voltage drops quite sharply, which provokes an increase in the load on the generator, the system constantly monitors this drop and limits the generator current at the level of the maximum generator power, the charging station, synchronously with this, reduces the allowable load to charge an electric vehicle. By this time, the charging session of the electric vehicle should be coming to an end, in connection with this, the electric vehicle requests less power, as soon as this power becomes less than the maximum power of the generator, part of the energy will be available to charge the internal batteries in this case, the generator current setting is kept at the same level. At the end of the charging session, the system switches to the mode of operation according to the case when charging a single battery with a DC generator.

Below is an example of the operation of a 120 kW device with a 60 kW generator and batteries 100A * h, 54 kW * h 538V 1C discharge.

After connecting the charging station to the electric vehicle, the initialization process takes place according to standard CCS protocols or another. During the interaction, the charging station announces the available power. Based on this data, the electric car sends back the voltage and current values that it would like to receive. The charging process starts with a minimum power of 1-5 kW from the battery of the installation or generator, depending on the case described above. The charging station gradually increases the available power by loading the battery, when the available power is reached, for example, 30kW, the generator is turned on, the generator is controlled by a current feedback regulator, the output of which is applied to the excitation winding. The regulator setpoint for the generator is calculated as follows:

1gen = (Rzar device + Rakb) / gen, but not more than Rgen max, where,

1gen - generator current;

Rzar devices - charger power;

Rakb - power per battery charge;

11gen - generator voltage;

Rgen max - the maximum power of the generator.

The process of gaining power by the charger continues, the voltage on the tires of the generator and the battery is constantly changing depending on the load of the battery from 580V to 530V. When the Charger's Available Power approaches the maximum generator power of 60kW, power will begin to be drawn from the battery. At this point in time, the voltage on the tires will be approximately 560V. In the process of loading the battery, the voltage begins to drop to 538v and below. The generator regulator at this moment reduces the generator excitation current, compensating for the excess load created as a result of the voltage drop, the current setting for this regulator is also adjusted to take into account this drop. The increase in available power for an electric vehicle will continue until the system reaches the maximum available battery power of 60 kW, limiting its current to 111A. When reaching maximum power output the parameters will be as follows: bus voltage 538V, generator current 111 A, battery current 111A. As the battery is discharged, the voltage will continue to drop slightly and at the time of the residual capacity of about 20%, the drop accelerates, the control system sees this and begins to reduce the available power for charging from 120 kW until the battery voltage stabilizes at the permissible minimum level, eventually at full discharge The battery, its component will become equal to zero, the available power of the charging station in this case will be equal to the power of the generator 60kW. If the electric car does not request all the available power of 120 kW, and for example only 80, the setting for the generator remains unchanged at 111 A, loading it to the maximum, while the remaining power is taken from the battery. With a further drop in the power requested by the electric vehicle to 60 kW and below, the released power is redirected to the battery charge. If the battery is already sufficiently charged or has insufficient temperature, the bus voltage will increase. The system is set to limit the voltage at the level of 582V, upon reaching this level, a slower regulator with voltage feedback comes into operation, acting on the generator current setting, it ensures voltage stabilization at the level of 582V.

Claims

CLAIM 1. A mobile electric vehicle charging device, comprising a fuel storage tank, an engine connected to it, driving a generator connected to a battery pack provided with a balancing means, an electric vehicle charging means, characterized in that the electric vehicle charging means means connected to the battery pack and the generator through the charge balancing unit, and the charge balancing unit is configured to balance the flow of electrical energy from the generator and / or battery pack depending on the information transmitted from the electric vehicle charging means and the balancing means of the battery pack, at the same time, the charge balancing unit is connected to the engine control unit with the possibility of transmitting control commands. 2. The mobile device according to claim 1, characterized in that it is installed on a truck chassis. 3. The mobile device according to claim 1, characterized in that the engine is a gas piston engine. 4. The mobile device according to claim 1, characterized in that the generator is a DC generator. 5. Mobile device according to claim 1, characterized in that the generator with the engine are installed on the same frame. 6. The mobile device according to claim 1, characterized in that the fuel storage tank is a gas mixture storage tank. 7. Mobile device according to claim 6, characterized in that the fuel storage tank is made in the form of two separate pressure vessels, where one is located inside the other in a stainless steel case with a high level of insulation. 8. The mobile device according to claim 7, characterized in that the fuel storage tank is provided with an outlet plug for safely venting excess pressure. 9. The mobile device according to claim 1, characterized in that liquefied natural gas or a mixture of liquefied natural gas and hydrogen is used as fuel for the engine. 10. The mobile device according to claim 1, characterized in that it additionally contains a heat recovery system, including a heat exchanger. 11. The mobile device according to claim 10, characterized in that the heat exchanger is installed outside the casing of the fuel tank, is connected to the engine water jacket using flexible hoses and is configured to receive heat from the engine cooling system. 12. The mobile device according to claim 1, characterized in that the battery pack consists of modular racks installed at the bottom of the chassis frame, in which batteries are placed. 13. The mobile device according to claim 1, characterized in that the means for balancing the battery pack includes balancers, each of which is located in its own battery, and which are connected to each other through an independent galvanically isolated line to be able to equalize the voltage of series-connected batteries batteries when charged at their common voltage. 14. Mobile device according to claim. 1, characterized in that each battery of the battery pack is additionally equipped with a Smart BMS system with microprocessor control. 15. The mobile device according to claim 1, characterized in that it is capable of charging electric vehicles with direct current of the CCS and ChaDeMo standard. 16. The mobile device according to claim 1, characterized in that it is additionally configured to work through a mobile application that provides users with the opportunity to reserve time and place for charging an electric vehicle, as well as the possibility of a contactless payment method for charging an electric vehicle.