Method and apparatus for charging an electric vehicle

Abstract

A method of charging an electric vehicle (3) comprising: - providing an external charging unit (5) and an external cooling unit (7); - connecting a battery power inlet (27) on the vehicle (3) to the charging unit (5) via a power cable (25); - connecting heat exchange connectors (20, 21) of a heat exchanger (22) of the vehicle (3) to the external cooling unit (7) via heat exchange conduits (15, 16); - during a peak charging time interval t pc providing cooling medium from a coolant tank (9) of the external cooling unit (7) to the vehicle (3) while providing a high level of power input via the power cable (25); and - during a subsequent charging time interval t sc after said peak charging time interval, providing cooling medium to said heat exchange connectors (20, 21) via a heat pump (10) while providing a second level of power input, lower than said first level, via said power cable (25).

Description

Technical Field

[0001] This invention relates to a method for charging an electric vehicle, comprising:

[0002] - Provides an external charging unit and an external cooling unit.

[0003] Connect the vehicle's battery power inlet to the charging unit via a power cable.

[0004] - Connect the vehicle's heat exchange connector to the external cooling unit via heat exchange pipes.

[0005] - The cooling medium is supplied to the vehicle from the coolant tank of the external cooling unit, and high-level power input is provided via power cables.

[0006] The present invention also relates to a charging station for fast charging of electric vehicles. Background Technology

[0007] Fast charging of electric vehicles at roadside charging stations is typically limited by battery temperature, which rises during charging. Often, especially in cold environments, the battery needs to be preheated at the start of a charging cycle.

[0008] Charging stations with external thermal regulation systems are known to have heat and cold sources, which are connected to an onboard heat exchanger, for example, via connectors located at the bottom of the vehicle. A power connector supplies DC power to the lithium-ion battery cells via cables. When delivering 300kW of power to an electric vehicle during a 6-12 minute charge of a 30kWh battery, it is anticipated that up to approximately 50kW of heat may be generated. The known heat and cold sources are equipped with heating and cooling units to provide a heat exchange medium contained within the heat and cold sources at the desired temperature. Summary of the Invention

[0009] One object of the present invention is to provide an efficient method for fast charging electric vehicles. Another object is to provide a charging station with an external thermal regulation system that is universal, relatively easy to install, and inexpensive.

[0010] The charging method according to the present invention includes:

[0011] -During the peak charging time interval t pc During this period, a cooling medium is supplied to the vehicle from the coolant tank of the external cooling unit, while a high-level power input is provided via power cables.

[0012] - Subsequent charging interval t after the peak charging intervalsc During this period, a cooling medium is supplied to the heat exchange connector via a heat pump, while a second-level power input, lower than that of the first level, is provided via a power cable.

[0013] By providing a cooling medium from the coolant tank during peak charging time, the battery can be charged at a high power, such as at least 300kW, while eliminating the 1-5 minute time intervals. pc The heat generated during this period is 30kW or more. This is followed by the subsequent charging time t. sc In the process, the charging power is reduced, for example to 250kW or lower, and cooling is provided by a heat pump during a period of 2-10 minutes.

[0014] The cooling power is achieved by using the coolant stored in the tank during high-power peak charging and a heat pump for cooling during subsequent lower-power charging, providing an efficient external vehicle cooling system with relatively low cooling power. The cooling system according to the invention can consist of a separate heat pump and a compact tank, which are relatively easy to install in existing charging infrastructure.

[0015] After one or more charging cycles are completed, the coolant in the coolant tank can be cooled by a heat pump to restore the coolant to its low cooling temperature. During charging, heat can be transferred to the hot storage tank to preheat the battery, especially when charging at low battery temperatures, such as in colder climates and during low-power driving.

[0016] During the peak charging time interval t pc The power supplied during this period can be at least 300kW, preferably at least 500kW, and in subsequent charging intervals t sc The power supplied during this period is less than 300kW.

[0017] The cooling medium in the coolant tank is capable of having a cooling energy of at least 2.5 kWh at a temperature of at least -10°C, preferably at least -20°C, and more preferably at least -30°C, within 1 minute. <t pc Peak charging time <5 minutes t pc This cooling is provided during the process. This charging cycle is particularly suitable for a typical 100kWh battery.

[0018] The method according to the present invention can charge a 100kWh battery to 80% SOC in 10 minutes to achieve a range of over 300km (at a power consumption of 200Wh / km).

[0019] The cooling tank according to the invention may include water and a cooling substance, such as ethylene glycol, in a volume between 25 liters and 500 liters, preferably between 25 liters and 100 liters, and has a relatively small size.

[0020] In an embodiment of the method according to the invention, wherein in 2 minutes <t sc <10-minute subsequent charging interval t sc During this period, the heat pump provides at least 10kW, preferably at least 20kW, of cooling power.

[0021] A 6kW heat pump with a coefficient of performance (COP) of 4 can generate 24kW of cooling power and 4kWh of energy, which can balance the charge to 60kWh at a charging rate of 500kW.

[0022] The charging station for charging electric vehicles according to the present invention may include:

[0023] - A charging unit having an electrical connector for connecting to the battery of an electric vehicle;

[0024] - A coolant connector, used to connect a cooling unit to the cooling system of an electric vehicle's battery; and

[0025] - A cooling unit, comprising a cold storage tank, a hot storage tank, and a heat pump. The hot and cold storage tanks are connected to the battery cooling system via coolant connectors. The heat pump is connected to each of the hot and cold storage tanks and is arranged to transfer heat from the cold storage tank to the hot storage tank.

[0026] Cold storage boxes can contain 10-100 liters of cooling medium.

[0027] An embodiment of the charging station according to the present invention includes two charging units, each having a cable and connector adapted to supply 250kW of power at 400V.

[0028] Another embodiment of the charging station according to the present invention includes a control unit adapted to:

[0029] -During the peak charging time interval t pc During this process, cooling medium is supplied from the cold storage tank to the vehicle's heat exchange unit, while high-level power is delivered via cables;

[0030] - Subsequent charging interval t after the peak charging interval sc The cooling medium is supplied from the heat pump to the vehicle's heat exchange unit, while simultaneously providing a second-stage power, lower than the first-stage power, via cables; and

[0031] - After one or more charging cycles are completed, the cooling medium in the cold storage tank is cooled by a heat pump.

[0032] The charging station according to the present invention may include a heat storage tank connected to a heat pump for providing a heat exchange medium from the heat storage tank to the heat exchange connector when the battery temperature is below a predetermined threshold.

[0033] Charging stations typically provide a voltage between 400V and 800V on the charging cables and connectors, or alternatively include two chargers, each with cables and connectors suitable for providing 250kW of power at 400V. These two cables can be used independently without a cooling system, and can be used together to provide fast charging when combined with a cooling system according to the present invention. Attached Figure Description

[0034] Embodiments of the charging method and charging station for fast charging of electric vehicles according to the present invention will be described in detail by way of non-limiting example with reference to the accompanying drawings. In the drawings:

[0035] Figure 1 A schematic diagram of a charging station for performing a charging method according to the present invention is shown, and

[0036] Figure 2 A graph showing the charging power, battery temperature, and total energy provided in the charging method according to the invention is shown. Detailed Implementation

[0037] Figure 1 A charging station 1 for charging the battery 2 of an electric vehicle 3 is shown. The charging station 1 includes a DC charging unit 5, a controller 6, and an external temperature control unit 7.

[0038] The temperature control unit 7 includes a hot storage tank 8, a cold storage tank 9, and a heat pump 10. The heat pump 10 is connected to the tanks 8 and 9 via thermal connections 30 and 31. These thermal connections include heat exchangers between the gas / liquid working medium in the heat pump 10 and the heat exchange liquids in the cold and hot storage tanks 8 and 9. In this configuration, the cold storage tank functions as the "evaporator" of the heat transfer system 8, 9, and 10, and the hot storage tank functions as the "condenser."

[0039] Storage tanks 8 and 9 are equipped with valves 11, 12, 13 and 14, and are connected via pipes 15 and 16 and connectors 17 and 18 to complementary connectors 20 and 21 of heat exchanger 22 on vehicle 2.

[0040] The charging unit 5 is attached to a complementary connector 27 on the vehicle 3 via a cable 25 with connectors 26 at its ends. The complementary connector 27 is attached to the battery 2 via a conductor 28. The cables 25 and connectors 26 and 27 are arranged to charge at 800V and 500kW. The charging unit 5 may have two cables 25, each with a connector 26. An electric vehicle 3 equipped with two complementary connectors 27 can use two charging cables to charge at twice the charging power of 400V and 250kW.

[0041] When the battery 2 of vehicle 3 needs to be recharged, the vehicle is driven to charging station 1 and connector 26 of charging unit 5 is connected to complementary connector 27 on vehicle 3. Connectors 17 and 18 of temperature control unit 7 are connected to connectors 20 and 21 of heat exchanger 22 on vehicle 3, allowing heat exchange fluid to circulate from heat storage tank 8 or cold storage tank 9 through heat exchanger 22. In one embodiment, connectors 20 and 21 may be located at the bottom of vehicle 3, and connectors 17 and 18 may be provided with an actuation mechanism that automatically engages with connectors 20 and 21 at the bottom when the vehicle is driven into the charging position.

[0042] During charging, controller 6 controls the power supplied by charging unit 5 and the supply of coolant from cold storage tank 9 or heat exchange fluid from hot storage tank 8. Controller 6 measures the battery and ambient temperature, and at temperatures below a predetermined threshold, controls valves 11-14 to supply heating medium from hot storage tank 8, so that battery 2 is preheated at the start of the charging cycle.

[0043] The cold storage unit 9 may include 50 liters of water / glycol as the heat exchange fluid, which is cooled to -30°C by the heat pump 10. The heat pump 10 is a 6kW heat pump with a COP of 4, enabling it to provide 24kW of cooling power.

[0044] The first peak charging time is typically 3 minutes. pc During this period, controller 6 controls charging unit 5 to supply 500kW of power to battery 2. At this charging power, approximately 10% of the power supplied to battery 2 is lost as heat, reaching 2.5kWh (9MJ) in a 3-minute charging time. This heat is cooled by coolant from cold storage tank 9. Cold storage tank 9 has a 50-liter volume of 50% ethylene glycol aqueous solution with a heat capacity Cp of 3.4kJ / kgK, which heats up to 20°C, removing 9MJ (2.5kWh) of heat.

[0045] After 3 minutes of fast charging, controller 6 switches charging unit 5 to a subsequent charging time t, which is typically 7 minutes. scDuring this period, it is charged at a power of 250kW. At this power, approximately 5% is lost as heat, and cooling of 12.5kW (1.4kWh) is required during the 7-minute period. Controller 6 activates heat pump 10 to cool the coolant in cold storage tank 9, and heat is removed from the battery through the operation of heat pump 10.

[0046] In a total charging time of 10 minutes t pc +t sc Battery 2 charges at approximately 60 kWh and requires 4 kWh of cooling.

[0047] By using a 6kW heat pump 10 with a COP of 4 and a power output of 24kW, 4kWh of energy can be removed for cooling. This is sufficient to remove 2.5kWh of heat during peak charging time and 1.4kWh during subsequent charging time. A cold buffer, such as a cold storage tank 9, is required to provide adequate cooling under all ambient temperature conditions and to transition gently to warmer climates.

[0048] When the total charging time is 10 minutes t pc +t sc Upon completion of charging, vehicle 3 is separated from charging unit 5 and temperature control unit 7. Controller 6 controls heat pump 10 and cold storage tank 9, causing heat pump 10 to remove heat from the coolant in cold storage tank 9 and transfer it to hot storage tank 8 and / or the environment, until the coolant in cold storage tank 9 returns to its operating temperature, for example -30°C.

[0049] Figure 2 The peak charging time t is shown to be 180s. pc The simulation included a charging power of 500kW during the initial phase and a subsequent charging power of 275kW for up to 600 seconds. A total power of 500kW was supplied while the battery core temperature remained at approximately 55°C. The coolant temperature was -10°C, the maximum cooling power was 32kW, and the battery was charged to 90% SOC.

[0050] If the temperature of battery 2 is low at the start of a charging cycle, controller 6 activates the thermal storage tank 8 to heat battery 2 at the start of the charging cycle or, if possible, before it begins. Up to 2 kWh is required to heat the battery from 0°C to 10°C before charging. A heat exchange medium (which may include water) is supplied from the 60°C thermal storage tank 8 at a flow rate of 30 liters / minute, resulting in the battery heating very rapidly at a rate of up to 10°C / minute.

Claims

1. A method for charging an electric vehicle (3), comprising: - Provides an external charging unit (5) and an external cooling unit (7); - Connect the battery power inlet (27) on the vehicle (3) to the charging unit (5) via a power cable (25); - Connect the heat exchange connectors (20, 21) of the heat exchanger (22) of the vehicle (3) to the external cooling unit (7) via heat exchange pipes (15, 16); -During the peak charging time interval t pc During this period, cooling medium is supplied from the cold storage tank (9) of the external cooling unit (7) to the vehicle (3), while high-level power input is provided via the power cable (25); and -The subsequent charging time interval t after the peak charging time interval sc During this period, cooling medium is supplied to the heat exchange connectors (20, 21) via a heat pump (10), while a second-level power input lower than the higher level is provided via the power cable (25).

2. The method according to claim 1, wherein after one or more charging cycles are completed, the cooling medium in the cold storage tank (9) is cooled by the heat pump (10).

3. The method according to claim 1 or 2, wherein during the peak charging time interval t pc The power supplied during this period is at least 300kW, and during the subsequent charging time interval t sc The power supplied during this period is less than 300kW.

4. The method of claim 3, wherein during the peak charging time interval t pc The power supplied during this period is at least 500kW, and during the subsequent charging time interval t sc The power supplied during this period is less than 300kW.

5. The method according to claim 1, wherein the cooling medium in the cold storage tank (9) comprises at least 2.5 kWh of cooling energy at a temperature of at least -10°C, within 1 minute. <t pc Peak charging time <5 minutes t pc Cooling is provided during this period.

6. The method according to claim 5, wherein the cooling medium in the cold storage tank (9) comprises at least 2.5 kWh of cooling energy at a temperature of at least -20°C, within 1 minute. <t pc Peak charging time <5 minutes t pc Cooling is provided during this period.

7. The method according to claim 6, wherein the cooling medium in the cold storage tank (9) comprises at least 2.5 kWh of cooling energy at a temperature of at least -30°C, within 1 minute. <t pc Peak charging time <5 minutes t pc Cooling is provided during this period.

8. The method according to claim 5, wherein the cold storage tank (9) comprises between 25 liters and 500 liters of water and cooling substance.

9. The method according to claim 8, wherein the cold storage tank (9) comprises between 25 liters and 100 liters of water and cooling substance.

10. The method according to claim 8 or 9, wherein the cooling substance is ethylene glycol.

11. The method according to claim 1 or 2, wherein within 2 minutes <t sc <10-minute subsequent charging interval t sc During this period, the heat pump (10) provides at least 10 kW of cooling power.

12. The method of claim 11, wherein within 2 minutes <t sc <10-minute subsequent charging interval t sc During this period, the heat pump (10) provides at least 20 kW of cooling power.

13. The method according to claim 1 or 2, further comprising the following step: A heat storage tank (8) is provided for heat exchange connection with the heat pump (10), and when the battery temperature is below a predetermined threshold, the heat exchange medium is supplied from the heat storage tank (8) to the heat exchange connector (20, 21).

14. A charging station for charging an electric vehicle (3), comprising: - Charging unit (5), which has an electrical connector (26) for connecting to the battery (2) of the electric vehicle (3); - Coolant connectors (17, 18) for connecting the cooling unit (7) to the cooling system of the battery (2) of the electric vehicle (3); - A cooling unit (7) comprising a cold storage tank (9), a hot storage tank (8) and a heat pump (10), wherein the hot storage tank (8) and the cold storage tank (9) are connectable to the cooling system of the battery (2) via the coolant connectors (17, 18), and the heat pump (10) is connected to each of the hot storage tank (8) and the cold storage tank (9) and is arranged to transfer heat from the cold storage tank (9) to the hot storage tank (8); - Control unit (6), which is adapted to: -During the peak charging time interval t pc During this period, the cooling medium is transferred from the cold storage tank (9). The heat exchanger (22) supplied to the vehicle (3) also provides high-level power via power cable (25); -The subsequent charging time interval t after the peak charging time interval sc During this period, cooling medium is supplied from the heat pump (10) to the heat exchanger (22) of the vehicle (3), while a second-level power lower than the high-level power is provided via the power cable (25); and - After one or more charging cycles are completed, the cooling medium in the cold storage tank (9) is cooled by the heat pump (10).

15. The charging station according to claim 14, wherein the cold storage box (9) comprises 10-100 liters of cooling medium.

16. The charging station according to claim 14 or 15, comprising two charging units (5), each of the charging units having a power cable (25) and an electrical connector (26) adapted to supply 250kW of power at 400V.

17. The charging station according to claim 14 or 15, comprising a heat storage tank (8) heat exchanged with the heat pump (10) for providing a heat exchange medium from the heat storage tank (8) to a heat exchange connector (20, 21) when the battery temperature is below a predetermined threshold.

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