Rapid charger for electric vehicle with extended service life and charging method using same

Abstract

A rapid charging method for an electric vehicle, according to an embodiment of the present invention, comprises the steps of: connecting, to a charging port of an electric vehicle, a charger cable including a DC power port for rapid charging, an AC power port for slow charging, and a communication port for communicating with the electric vehicle so as to start rapid charging of an electric vehicle battery by supplying DC power through the DC power port (S1); maintaining rapid charging of the electric vehicle battery through the DC power port until the charge amount of the electric vehicle battery reaches 80% or more and the charge rate becomes lower than or equal to a first speed set in advance through information about a charge rate included in a communication signal between the charging port and the communication port (S2); stopping the supply of DC power and supplying AC power to the charging port through the AC power port when the charge amount is 80% or more and the charge rate becomes lower than or equal to the first speed (S3); and slowly charging all or part of an uncharged amount of the electric vehicle battery through the AC power port when AC power is supplied to the charging port. Accordingly, AC power is supplied instead of DC power in a section during which the charging speed drops sharply in the latter half of rapid charging, thereby reducing the usage time of a power module, such that the maintenance cost of the charger can be significantly reduced.

Description

Rapid charger for electric vehicles with extended service life and charging method using the same

[0001] The present invention relates to a rapid charger for extending the service life of an electric vehicle battery and a rapid charging method using the same.

[0002] Electric vehicles are vehicles that obtain their driving energy from electric energy rather than from the combustion of fossil fuels like conventional internal combustion engine vehicles. They have many advantages, including no exhaust fumes, very little noise, lower maintenance costs compared to conventional internal combustion engine vehicles, and improved environmental issues due to the reduction of carbon dioxide emissions.

[0003] Charging the battery for driving the motor is essential for operating these electric vehicles. Charging stations equipped with one or more chargers are being installed in various locations, including apartment complexes, large supermarkets, public institution parking lots, and even highway rest areas. When the charger cable is connected to the externally exposed charging port, the electric vehicle battery is charged by receiving AC or DC power from the charger. The electric vehicle's charging port and charger cable must be of the same standard to ensure electrical connection and battery charging. Depending on the standard, the charger cable and charging port may have ports, pins, or connectors that can receive DC power, ports, pins, or connectors that can receive AC power, or ports, pins, or connectors that can receive both DC and AC power.

[0004] For example, referring to Fig. 4a, the CCS (Combined Charging System) type 1 standard, which is widely used in Korea and North America, is configured as a combo type including 5 pins (or connectors) for slow charging at the top and 2 pins (or connectors) for rapid charging at the bottom. Of the 5 pins at the top, the upper 2 are pins or connectors for AC power supply, and the lower 2 are pins or connectors for communication including a ground line. The 2 pins at the bottom are pins or connectors for DC power supply.

[0005] Also, referring to Fig. 4b, in the case of the NACS (North American Charging Standard) type specification used in several countries including North America, it is composed of a total of 5 pins or connectors, the upper 2 pins are pins or connectors for selectively supplying DC power or AC power, and the lower 3 pins are pins or connectors for communication.

[0006] When AC power is supplied to an electric vehicle's charging port, it is converted to DC power via the onboard charger (OBC) included in the vehicle and then supplied to the battery to charge. This requires a relatively low-output OBC, resulting in slow charging. Conversely, when DC power is supplied to the electric vehicle's charging port, the battery is directly connected to the DC power supply, bypassing the OBC. This allows for relatively high-output charging and rapid charging. This requires a high-output charger, which in turn requires a high-output charger.

[0007] Chargers that supply DC power receive AC power from an external power source, convert it to DC power through an internal power module, and then supply power to the electric vehicle's charging port. Power modules utilize expensive components, such as SiC power devices, to ensure stable DC power conversion. Recently, the output of a single power module is limited to approximately 30 kW, so a charger typically requires four power modules for rapid charging, accounting for over 40% of the total cost. The lifespan of a power module is highly dependent on usage time, and as usage time accumulates, the maintenance costs associated with replacing power modules become significant.

[0008] When using DC rapid charging with a charger containing multiple power modules, the initial charging speed is very fast due to the characteristics of the battery and surrounding systems, but as the charge level increases, the later charging speed decreases rapidly. Consequently, to fully charge an electric vehicle battery, the power modules must be used for extended periods while maintaining the rapidly decreasing later charging speed. This results in an inefficient charging environment that only increases charger maintenance costs.

[0009] An embodiment of the present invention provides a rapid charging method and charger for an electric vehicle, which reduces the usage time of a power module and significantly reduces the maintenance cost of the charger by allowing rapid charging using a charger cable configured to separately include a DC power port and an AC power port or share the same port, to initially charge rapidly using a DC power source, and switching to slow charging using an AC power source when the amount of charge exceeds a certain level and the charging speed drops below a certain level, thereby reducing the usage time of a power module.

[0010] The problems to be solved by the present invention are not limited to the problem(s) mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

[0011] A rapid charging method for an electric vehicle according to an embodiment of the present invention may include a step (S1) of connecting a charger cable including a DC power port for rapid charging, an AC power port for slow charging, and a communication port for communicating with the electric vehicle to a charging port of the electric vehicle, and starting rapid charging of the electric vehicle battery by supplying DC power through the DC power port; a step (S2) of maintaining rapid charging of the electric vehicle battery through the DC power port until the charge amount of the electric vehicle battery is 80% or more and the charge rate becomes lower than or equal to a first preset rate through information about the charge rate included in a communication signal between the charging port and the communication port; a step (S3) of stopping the supply of DC power and supplying AC power to the charging port through the AC power port when the charge amount is 80% or more and the charge rate becomes lower than or equal to the first rate; and a step (S4) of slowly charging all or part of an uncharged amount of the electric vehicle battery through the AC power port when AC power is supplied to the charging port.

[0012] In the above embodiment, if AC power is not supplied to the charging port after the step S3, the step (S31) of stopping the application of AC power through the AC power port and re-maintaining rapid charging of the electric vehicle battery by supplying DC power through the DC power port until the charging speed becomes lower than or equal to a preset second speed; and the step (S32) of stopping the supply of DC power and re-applying AC power to the charging port through the AC power port when the charging speed becomes lower than or equal to the preset second speed.

[0013] In the above embodiment, the second speed may be less than the first speed.

[0014] In the above embodiment, the first speed may be 11 kW and the second speed may be 7 kW.

[0015] In the above embodiment, the DC power port and the AC power port can share a connector formed of two metals.

[0016] An electric vehicle rapid charger according to an embodiment of the present invention comprises: a charger cable including a DC power port for rapid charging, an AC power port for slow charging, and a communication port for communication with the electric vehicle; And a control unit for charging the electric vehicle battery through the charger cable by mutually switching between a DC power supply mode through the DC power port and an AC power supply mode through the AC power port, and when the charger cable is connected to the charging port of the electric vehicle battery, the control unit switches to the DC power supply mode, and the charger cable supplies DC power to the charging port through the DC power port to start rapid charging, and the control unit maintains the DC power supply mode until the charge amount of the electric vehicle battery becomes 80% or more and the charging speed becomes lower than or equal to a first preset speed through information about the charging speed included in a communication signal between the charging port and the communication port, and when the charge amount is 80% or more and the charging speed becomes lower than or equal to the first speed, the control unit switches to the AC power supply mode, and the charger cable supplies AC power to the charging port through the AC power port, and when AC power is supplied to the charging port, the charger cable supplies all or part of the uncharged amount of the electric vehicle battery through the AC power port. Some can be slow charged.

[0017] In the above embodiment, when the charger cable supplies AC power to the charging port through the AC power port, and AC power is not supplied to the charging port, the control unit switches to a DC power supply mode, and the charger cable charges the electric vehicle battery by supplying DC power through the DC power port until the charging speed becomes lower than or equal to a preset second speed, and when the charging speed becomes lower than or equal to the second speed, the control unit switches to an AC power supply mode, and the charging cable supplies AC power to the charging port through the AC power port, and when AC power is supplied to the charging port, all or part of the uncharged amount of the electric vehicle battery can be slowly charged through the AC power port.

[0018] In the above embodiment, the second speed may be less than the first speed.

[0019] In the above embodiment, the first speed may be 11 kW and the second speed may be 7 kW.

[0020] In the above embodiment, the DC power port and the AC power port can share a connector formed of two metals.

[0021] According to an embodiment of the present invention, when a rapid charger and charging method for an electric vehicle are used to rapidly charge an electric vehicle using a charger cable that includes a DC power port and an AC power port as separate, independent pins or connectors, or a charger cable that can selectively supply DC power or AC power through the same pin or connector, the initial charging is performed as rapid charging using DC power, and when the amount of charge exceeds a certain level and the charging speed drops below a certain level, the charging is switched to slow charging using AC power, thereby reducing the usage time of the power module and significantly reducing the maintenance cost of the charger.

[0022] FIG. 1 and FIG. 2 are flowcharts illustrating each step of a rapid charging method for an electric vehicle according to embodiments of the present invention.

[0023] FIG. 3 is a block diagram schematically illustrating each component of an electric vehicle charger according to an embodiment of the present invention.

[0024] Figure 4 is a drawing schematically illustrating the types of standards applied to electric vehicle chargers.

[0025]

[0026] *Explanation of major symbols in the drawing

[0027] 11: Charger cable

[0028] 13: Control unit

[0029] The advantages and / or features of the present invention, and the methods for achieving them, will become clearer with reference to the embodiments described in detail below together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms. These embodiments are provided only to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

[0030]

[0031] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.

[0032] FIG. 1 and FIG. 2 are flowcharts illustrating each step of a rapid charging method for an electric vehicle according to embodiments of the present invention.

[0033] Referring to Fig. 1, a rapid charging method for an electric vehicle according to an embodiment of the present invention is performed by connecting a charger cable included in an electric vehicle charger to a charging port attached to the electric vehicle. The charger cable includes a DC power port for rapid charging, an AC power port for slow charging, and a communication port for communication with the electric vehicle. The DC power port and the AC power port may be configured as separate pins or connectors, as in the CCS1 standard of Fig. 4a. Alternatively, the DC power port and the AC power port may be configured to share a pair of pins or connectors formed of two metals, as in the NACS standard of Fig. 4b. The communication port transmits and receives communication signals containing information regarding the charging of the electric vehicle battery, such as charge amount, charge speed, voltage, elapsed charging time, or estimated charging time, to and from the charging port of the electric vehicle. The communication signals may be signals in the form of Power Line Communication (PLC), Pulse Width Modulation (PWM), or Controller Area Network (CAN).

[0034] In step S1, the charger cable is connected to the charging port of the electric vehicle, and DC power is first supplied to the charging port of the electric vehicle through the DC power port, thereby starting rapid charging of the electric vehicle battery.

[0035] In stage S2, rapid charging via the DC power port continues until the electric vehicle battery reaches 80% or more and the charging speed drops below a preset first rate. This preset first rate can be approximately 10 kW or more and 15 kW or less, but can also be set to a specific value, such as 11 kW.

[0036] In stage S3, when the charge level exceeds 80% and the charging speed falls below the first speed, the DC power supply is cut off and AC power is supplied to the EV's charging port through the AC power port. When AC power is supplied, the EV's charging port may accept AC power and supply it to the battery or internal systems through current flow. However, if the AC power is not accepted, AC power may not be supplied to the EV. The AC power supply is a preliminary test step for AC power supply, and whether AC power is supplied to the charging port after AC power supply is applied is related to the current charging speed, i.e., the output supplied by the charger. The charging speed is determined by factors such as the battery's charge level, electrochemical characteristics, and the tolerance of the power supplied from that charge level, and therefore cannot be unilaterally changed by the charger. Slow charging via AC power is set to occur only below a certain charging speed, depending on the tolerance of related systems such as the EV's OBC. For example, the specific charging speed may be set to 11 kW or 7 kW. If AC power exceeding the set charging speed is applied, the charging port blocks the AC power supply. Since the charger does not have information regarding the specific charging speed of the EV being charged, it sequentially applies the specific charging speeds of commercially available EVs to ensure slow charging via AC power. If AC power below the set charging speed is applied, the charging port allows AC power supply.

[0037] At stage S4, if AC power is supplied to the charging port, the remaining battery capacity of the electric vehicle is charged via the AC power port. This charging can be all or part of the remaining capacity, and slow charging is achieved via AC power.

[0038] After step S3, if AC power is not supplied to the charging port, steps S31 and S32 are passed through to step S4. If AC power is not supplied to the charging port, that is, if the charging speed (output) of the AC power supplied from the AC power port is greater than the slow charging speed set for the electric vehicle, the AC power supply through the AC power port is stopped, and rapid charging of the electric vehicle battery is re-maintained by supplying DC power through the DC power port until the charging speed becomes lower than a preset second speed (S31). Re-maintaining rapid charging by supplying DC power means resuming charging by DC power, and although it is a lower speed than the initial charging speed, it is an expression to distinguish it from charging by AC power. The second speed is a value lower than the first speed, and can be, for example, 5 kW or more and less than 10 kW, or a specific value such as 7 kW.

[0039] At step S32, if the charging speed falls below the second speed, the DC power supply is cut off and AC power is re-applied to the charging port through the AC power port. Thereafter, if AC power is supplied to the charging port, all or part of the uncharged amount of the electric vehicle battery is slowly charged through the AC power port according to step S4. If AC power is not supplied to the charging port, the process returns to step S31, and steps S31 through S4 are performed.

[0040]

[0041] FIG. 3 is a block diagram schematically illustrating each component of an electric vehicle charger according to an embodiment of the present invention.

[0042] Referring to FIG. 3, an electric vehicle rapid charger includes a charger cable that is connected to a charging port of an electric vehicle to supply power and a control unit that switches between a supply mode using direct current power or alternating current power.

[0043] The charger cable includes a DC power port for rapid charging, an AC power port for slow charging, and a communication port for communication with the electric vehicle. As previously described, the DC and AC power ports may be configured with separate pins or connectors, or they may share the same pins or connectors. The pins or connectors may be formed by two pieces of metal, i.e., a pair of metals.

[0044] The control unit switches between DC power supply mode via the DC power port and AC power supply mode via the AC power port. Switching between modes means selectively applying either mode.

[0045] When the charger cable is connected to the charging port of the electric vehicle battery, the control unit switches to the DC power supply mode, i.e., sets it, and the charger cable supplies DC power to the charging port through the DC power port to initiate rapid charging.

[0046] The control unit maintains the DC power supply mode until the electric vehicle battery reaches 80% or more charge and the charging speed falls below a preset first rate, as determined by charging speed information contained in the communication signal between the charging port and the communication port. The preset first rate may be approximately 10 kW or more and 15 kW or less, or may be set to a specific value, such as 11 kW.

[0047] When the charge level is 80% or more and the charging speed is lower than the first speed, the control unit switches to AC power supply mode, and the charger cable supplies AC power to the charging port through the AC power port.

[0048] When AC power is supplied to the charging port, the charger cable slowly charges all or part of the uncharged battery of the electric vehicle through the AC power port.

[0049] If AC power is not supplied to the charging port, the control unit switches to DC power supply mode, and the charger cable charges the electric vehicle battery by supplying DC power through the DC power port until the charging speed falls below a preset second speed. The second speed is a value lower than the first speed, and can be, for example, 5 kW or more and less than 10 kW, or a specific value such as 7 kW.

[0050] When the charging speed becomes lower than the second speed, the control unit switches to the AC power supply mode, the charging cable supplies AC power to the charging port through the AC power port, and when AC power is supplied to the charging port, all or part of the uncharged amount of the electric vehicle battery is slowly charged through the AC power port. When AC power is not supplied to the charging port, charging is resumed through the DC power port, and when it becomes lower than a certain speed, the application of AC power and slow charging through the supply of AC power can be appropriately repeated. Since the technical features described above with respect to FIGS. 1 and 2 are applicable, overlapping content will be omitted for the sake of brevity of the following description.

[0051]

[0052] According to the electric vehicle rapid charging method and rapid charger, which are embodiments of the present invention, charging is performed by supplying AC power instead of DC power for the low-speed charging section that occurs in the latter half of rapid charging, thereby significantly reducing the usage time of the power module included in the charger, and thus significantly reducing the maintenance cost of the charger.

[0053] Current 100kW rapid chargers incorporate four 30kW or five 20kW power modules. While the output of each power module is trending higher, their price remains high. The integrated power modules may be fully utilized throughout the entire charging process, or they may be fully utilized during the initial fast charging phase and only partially utilized during the later, slower charging phase.

[0054] Looking at the current rapid charging landscape, as previously explained, the charging speed decreases sharply towards the end of the charge cycle. As an example, let's consider a 100-kWh electric vehicle battery being charged with a 100-kW rapid charger. The charging speed reaches its maximum when the battery's charge level is between 0 and 60%. As the charge level increases, the charging speed decreases sharply, dropping to approximately 7 to 11 kW above 90%.

[0055] Looking at the measured output and charging time of the charger by section based on the currently installed charger, it takes 36 minutes with 100 kW to charge up to 60% (60 kWh), 15 minutes with 50 kW to charge from 60 to 80% (20 kWh), 15 minutes with 25 kW to charge from 80 to 90% (10 kWh), and 85 minutes with 7 kW to charge from 90 to 100% (10 kWh). In other words, it takes 66 minutes to charge from 0 to 90% of the charge, but a whopping 85 minutes to charge to 100%. Although it is called rapid charging, in reality, slow charging is performed due to the slow charging speed in the latter half to fully charge 100%. If the power module built into the rapid charger is continuously used during this long charging section in the latter half, the life of the power module will be inefficiently reduced.

[0056] According to embodiments of the present invention, by switching the charging mode to supply AC power instead of DC power in the latter half of rapid charging, there is an advantage in that the power module is prevented from being used inefficiently, thereby reducing the maintenance costs of the charger. Since the time required to charge the second half of the 10% charge amount is actually longer than the time required to charge the first half of the 90% charge amount, applying the rapid charging method and rapid charger according to the present invention can increase the lifespan of the power module by at least two times.

[0057]

[0058] While specific embodiments of the present invention have been described so far, it is clear that various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the scope of the claims set forth below, but also by equivalents thereof.

[0059] Although the present invention has been described with reference to limited embodiments and drawings, it is not limited to the above-described embodiments. Those skilled in the art will appreciate that various modifications and variations are possible based on this disclosure. Therefore, the scope of the present invention should be understood solely by the scope of the claims set forth below, and all equivalent or equivalent modifications thereof are deemed to fall within the scope of the present invention.

Claims

1. In a rapid charging method for an electric vehicle, A step (S1) in which a charger cable including a DC power port for rapid charging, an AC power port for slow charging, and a communication port for communication with the electric vehicle is connected to a charging port of the electric vehicle, thereby starting rapid charging of the electric vehicle battery by supplying DC power through the DC power port; A step (S2) of maintaining rapid charging of the electric vehicle battery through the DC power port until the charge amount of the electric vehicle battery is 80% or more and the charging speed becomes lower than or equal to a preset first speed through information about the charging speed included in a communication signal between the charging port and the communication port; When the charge amount is 80% or more and the charging speed is lower than the first speed, the step (S3) of stopping the supply of DC power and supplying AC power to the charging port through the AC power port; and A rapid charging method for an electric vehicle, characterized in that it comprises a step (S4) of slowly charging all or part of the uncharged amount of the electric vehicle battery through the AC power port when AC power is supplied to the charging port.

2. In paragraph 1, If AC power is not supplied to the charging port after the S3 step, the AC power supply through the AC power port is stopped, and the rapid charging of the electric vehicle battery is maintained by supplying DC power through the DC power port until the charging speed becomes lower than the preset second speed (S31); and A rapid charging method for an electric vehicle, characterized in that it includes a step (S32) of stopping the supply of direct current power and reapplying alternating current power to the charging port through the alternating current power port when the charging speed becomes lower than a preset second speed.

3. In paragraph 2, A rapid charging method for an electric vehicle, characterized in that the second speed is less than the first speed.

4. In paragraph 2, A rapid charging method for an electric vehicle, characterized in that the first speed is 11 kW and the second speed is 7 kW.

5. In paragraph 1, A rapid charging method for an electric vehicle, characterized in that the DC power port and the AC power port share a connector formed of two metals.

6. In electric vehicle rapid chargers, A charger cable including a DC power port for rapid charging, an AC power port for slow charging, and a communication port for communication with the electric vehicle; and A control unit for charging the electric vehicle battery through the charger cable by switching between a DC power supply mode through the DC power port and an AC power supply mode through the AC power port; When the charger cable is connected to the charging port of the electric vehicle battery, the control unit switches to the DC power supply mode, and the charger cable supplies DC power to the charging port through the DC power port to initiate rapid charging. The control unit maintains the DC power supply mode until the charge amount of the electric vehicle battery is 80% or more and the charging speed becomes lower than or equal to a preset first speed through information about the charging speed included in the communication signal between the charging port and the communication port. When the above charge amount is 80% or more and the above charging speed is lower than the first speed, the control unit switches to the AC power supply mode, and the charger cable supplies AC power to the charging port through the AC power port. An electric vehicle rapid charger, characterized in that when AC power is supplied to the charging port, the charger cable slowly charges all or part of the uncharged amount of the electric vehicle battery through the AC power port.

7. In paragraph 6, If the above charger cable supplies AC power to the charging port through the AC power port, and AC power is not supplied to the charging port, The control unit switches to a DC power supply mode, and the charger cable charges the electric vehicle battery by supplying DC power through the DC power port until the charging speed becomes lower than a preset second speed. An electric vehicle rapid charger characterized in that when the charging speed becomes lower than the second speed, the control unit switches to an AC power supply mode, the charging cable supplies AC power to the charging port through the AC power port, and when AC power is supplied to the charging port, all or part of the uncharged amount of the electric vehicle battery is slowly charged through the AC power port.

8. In paragraph 7, An electric vehicle rapid charger, characterized in that the second speed is lower than the first speed.

9. In paragraph 7, An electric vehicle rapid charger characterized in that the first speed is 11 kW and the second speed is 7 kW.

10. In paragraph 6, An electric vehicle rapid charger characterized in that the DC power port and the AC power port share a connector formed of two metals.

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