A cable heating system for a charging gun and a DC charging system for an electric vehicle

Abstract

The present invention relates to a cable heating system for a charging gun and a DC charging system for an electric vehicle, belonging to the technical field of DC charging. The cable heating system includes a single-phase rectification module, a DC switch, a charging gun, and a charging socket. The single-phase rectification module, the DC switch, the pins of the charging gun, and the jacks of the charging socket are connected in sequence to form a low-voltage energized loop, and a connection resistor is serially provided on this loop. The two ends of the connection resistor are connected between two jacks of the charging socket. It further includes a control module, which controls the connection of the DC switch and is used to control the DC switch, thereby realizing the on-off control of the low-voltage energized loop, and realizing the heating of the cable on the charging gun through the low-voltage energized loop. In the cable heating system of the present invention, before vehicle charging, by controlling the DC switch through the control module, the low-voltage energized loop can be made to conduct, realizing the heating of the cable of the charging gun, and solving the problem of inconvenient operation caused by the stiffness of the charging gun cable before vehicle charging.

Description

Technical Field

[0001] The present invention belongs to the technical field of DC charging, and particularly relates to a cable heating system for a charging gun and a DC charging system for an electric vehicle. Background Art

[0002] In the prior art, generally, a new energy vehicle is charged through a DC charging system. The DC charging system includes a DC charging pile (i.e., a DC charger). The output end of the AC / DC module in the charging pile is connected to a charging gun, and the control module in the charging pile controls the conduction of a charging loop composed of a three-phase power supply, the AC / DC module, the charging gun, and the power battery to realize the charging of the power battery.

[0003] However, during the vehicle charging process, to achieve fast charging with large current and high voltage, the connection between the charging device and the vehicle high-voltage line is often required. This connection is generally realized by connecting the power pins in the charging gun and the power jacks in the vehicle charging socket. Currently, due to limitations in technology, process, materials, etc., the lifespan of the power pins in the charging gun is generally 10,000 times. Under some illegal operations such as hot plugging, the lifespan of the pins will be further reduced. If charging continues after the lifespan of the pins expires, the contact resistance between the pins and the socket will increase, and the heat generation during the charging process will increase sharply, resulting in a decrease in charging efficiency, ablation of the charging gun and the charging socket, and even problems such as vehicle fire.

[0004] Moreover, during the vehicle charging process, the charging current is as high as 250A, and the charging gun cable uses an 80mm 2 harness, and multiple layers of rubber protection are added, resulting in the charging gun cable being rigid in a low-temperature environment in winter, which is very inconvenient for users to operate and the charging experience is poor. Summary of the Invention

[0005] The purpose of the present invention is to provide a cable heating system for a charging gun and a DC charging system for an electric vehicle to solve the problem that the charging gun cable is rigid and inconvenient to operate in a low-temperature environment in winter.

[0006] Based on the above purpose, a technical solution for a DC charging system of an electric vehicle is as follows:

[0007] It includes a charger, as well as a control module, a three-phase rectifier charging module, a first switch, and a charging gun provided in the charger. Among them, the AC side of the three-phase rectifier charging module is used to connect to the power supply, and the DC side of the three-phase rectifier charging module, the first switch, and the charging gun are connected in sequence to form a charging loop; a charging socket is provided on the charger body, and two jacks are provided on the charging socket for correspondingly connecting two pins on the charging gun;

[0008] It also includes a single-phase rectification module and a second switch. The single-phase rectification module is connected to the second switch to form a low-voltage branch, and this low-voltage branch is connected in parallel to the high-voltage branch formed by the three-phase rectification charging module and the first switch; and a resistor is connected between the two jacks, and the low-voltage branch is connected in sequence through the pin of the charging gun, the jack of the charging socket, and the resistor to form a low-voltage energized circuit;

[0009] The control module is controllably connected to the first switch and the second switch, and is used to control the conduction of the charging circuit by using the first switch to realize vehicle charging through the charging circuit; and before vehicle charging, the second switch is used to control the conduction of the low-voltage energized circuit to heat the cable on the charging gun through the low-voltage energized circuit.

[0010] The beneficial effects of the above technical solutions are:

[0011] In the DC charging system of the present invention, before vehicle charging, the control module controls the first switch to be off and the second switch to be on, so that the low-voltage energized circuit is conducted and the charging circuit is disconnected, realizing the heating of the cable of the charging gun; then, the control module controls the first switch to be on and the second switch to be off, so that the charging circuit is conducted and the low-voltage energized circuit is disconnected, realizing the charging of the battery, and solving the problem of inconvenient operation caused by the stiffness of the charging gun cable before vehicle charging.

[0012] Further, to solve the problem of the heating time of the charging gun cable. The control module is also communicatively connected to a temperature sensor built in the pin for detecting the heating temperature after the pin and the jack are in contact, and the control module is used to control the heating time of the charging gun cable according to the temperature rise of the heating temperature.

[0013] The effect is: using the low-voltage energized circuit to realize the first function, heating the charging gun cable, and using the temperature data of the temperature sensor to judge the magnitude of the temperature rise, and timely disconnecting the low-voltage energized circuit to prevent the cable of the charging gun from overheating and the heating time from being too long.

[0014] Further, to solve the problems of reduced charging efficiency, ablation of the charging gun and the charging socket caused by continued use when the life of the pin of the charging gun in the existing charging system expires, the control module is also used to perform a life warning judgment on the charging gun according to the temperature rise of the heating temperature.

[0015] The effect is: using the low-voltage energized circuit to realize the second function, that is, when there is no need to heat the charging gun cable, a low-voltage and large-current signal can be generated in the low-voltage energized circuit. By monitoring the temperature rise after the pin and the jack are in contact, it is judged whether the temperature rise is too large, the life of the charging gun can be predicted, and a warning can be given, enabling the user to repair the charging gun in time to avoid problems such as reduced charging efficiency and ablation of the charging gun and the charging socket.

[0016] Further, in order to control the first switch and the second switch, the control module is connected to the coils of a first contactor and a second contactor. The first switch is the switch of the first contactor, and the second switch is the switch of the second contactor.

[0017] Further, to facilitate the user to preheat the cable of the charging gun as needed, the control module is also used for wireless communication connection with the user's handheld terminal or PC terminal, to receive the control instructions sent by the user, perform pre-booked charging of the vehicle, and control the low-voltage power-on circuit to conduct before the vehicle is charged, so as to realize the heating of the cable of the charging gun.

[0018] Based on the above purpose, the technical solution of a cable heating system for a charging gun is as follows:

[0019] It includes a single-phase rectification module, a DC switch, a charging gun and a charging socket. The single-phase rectification module, the DC switch, the pins of the charging gun and the jacks of the charging socket are connected in sequence to form a low-voltage power-on circuit, and a connection resistor is serially arranged on this circuit. Both ends of the connection resistor are connected between two jacks of the charging socket;

[0020] It further includes a control module, which is controllably connected to the DC switch and used to control the DC switch, and thus realize the on-off control of the low-voltage power-on circuit, and realize the heating of the cable on the charging gun through the low-voltage power-on circuit.

[0021] The beneficial effects of the above technical solution are:

[0022] In the cable heating system of the present invention, before the vehicle is charged, by controlling the DC switch through the control module, the low-voltage power-on circuit can be made to conduct, realizing the heating of the cable of the charging gun, and solving the problem of inconvenient operation caused by the stiffness of the charging gun cable before vehicle charging.

[0023] Further, to solve the problem of the heating time of the charging gun cable. The control module is also communicatively connected to a temperature sensor built in the pin, for detecting the heating temperature after the pin and the jack are in contact, and the control module is used to control the heating time of the cable of the charging gun according to the temperature rise of the heating temperature.

[0024] The effect is: using the low-voltage power-on circuit to achieve the first function, heating the charging gun cable, and using the temperature data of the temperature sensor to judge the size of the temperature rise, and timely disconnecting the low-voltage power-on circuit to prevent the cable of the charging gun from overheating and the heating time from being too long.

[0025] Further, to solve the problems of reduced charging efficiency, ablation of the charging gun and the charging socket caused by continued use of the charging pin of the charging gun when its life expires in the existing charging system, the control module is further configured to perform a life warning determination of the charging gun according to the temperature rise of the heating temperature.

[0026] The effect is as follows: The second function is realized by using the low-voltage energization loop. That is, when it is not necessary to heat the charging gun cable, a low-voltage and large-current signal can be generated in the low-voltage energization loop. By monitoring the temperature rise after the pin and the jack are in contact, it is judged whether the temperature rise is too large, so as to predict the life of the charging gun and give a warning, enabling the user to repair the charging gun in time and avoiding problems such as reduced charging efficiency, ablation of the charging gun and the charging socket.

[0027] Further, to realize the control of the DC switch, the control module is connected to the coil of the DC contactor, and the DC switch is the switch of the DC contactor.

[0028] Further, to facilitate the user to preheat the cable of the charging gun as needed, the control module is further configured to perform wireless communication connection with the user's handheld terminal or PC terminal, receive the control instruction sent by the user, perform reserved charging of the vehicle, and control the low-voltage energization loop to conduct before the vehicle is charged, so as to realize the heating of the cable of the charging gun. Description of the Drawings

[0029] Figure 1 is a schematic diagram of the DC charging system in the embodiment of the charging system of the present invention;

[0030] Figure 2 is a schematic diagram of the connection between the control module and other components in the embodiment of the charging system of the present invention. Detailed Embodiment

[0031] The following further describes the detailed embodiment of the present invention with reference to the drawings.

[0032] Embodiment of the charging system:

[0033] This embodiment provides a DC charging system for an electric vehicle, as Figure 1 shown, including a charger, and a control module, a three-phase rectifier charging module (AC / DC charging module), a first contactor switch K1, and a charging gun arranged in the charger. Among them, the AC side of the three-phase rectifier charging module is connected to a three-phase power supply, and the DC side of the three-phase rectifier charging module, the first contactor switch K1, and the charging gun are connected in sequence to form a charging loop. Moreover, a charging socket CZ is arranged on the charger body, and two jacks C2 are arranged on the charging socket for correspondingly connecting two pins C1 on the charging gun to charge the power battery of the electric vehicle. And, Figure 1As shown, a resistor R is connected between two jacks C2 of the socket CZ, and the two power jacks C2 are short-circuited through this resistor R.

[0034] Figure 1 In this system, it further includes a single-phase rectification module (i.e., single-phase AC / DC) and a second contactor switch. The single-phase rectification module is connected to the second contactor switch K2 to form a low-voltage branch, and this low-voltage branch is connected in parallel to a high-voltage branch formed by a three-phase rectification charging module (AC / DC charging module) and a first contactor switch K1.

[0035] In this system, the control module controls the first contactor switch K1 connected to the high-voltage branch and the second contactor switch K2 connected to the low-voltage branch; the specific control method is as Figure 2 shown. The control module is connected to the coil of the first contactor and the coil of the second contactor, and is used to control the first contactor switch K1 and the second contactor switch K2 respectively, so as to achieve the purpose of controlling the on and off of the high-voltage branch and the low-voltage branch.

[0036] In this system, the control module is also communicatively connected to a temperature sensor, which is built into the power pin C1 of the charging gun and is used to collect the temperature of the power pin C1, that is, the heating temperature after the pin and the jack are in contact.

[0037] The working principle of this charging system is as follows:

[0038] (1) Before the vehicle is charged, the charging gun is placed in the charging socket CZ of the charger. The power pin C1 of the charging gun contacts the power jack C2 of the socket. The control module controls the first contactor switch K1 to be disconnected and the second contactor switch K2 to be closed. A low-voltage energized circuit is formed through the low-voltage branch, the cable of the charging gun, the power pin C1, the power jack C2, and the resistor R, so that the low-voltage energized circuit is conducted and the charging circuit is disconnected, realizing the heating of the cable of the charging gun.

[0039] The heating time of the cable can be determined according to the temperature rise of the heating temperature after the pin and the jack are in contact. Specifically, through the communication connection between the control module and the temperature sensor, the heating temperature after the pin and the jack are in contact is obtained, and the temperature rise is judged, so as to control the heating time of the cable of the charging gun. As other embodiments, a time threshold can also be set for heating timing, and the cable heating stops when the time is up.

[0040] (2) After the cable is heated, the vehicle is charged normally. The control module controls the first contactor switch K1 to be closed and the second contactor switch K2 to be disconnected. This charging system is connected to the power battery of the vehicle through the high-voltage branch and the charging gun to form a power supply circuit to charge the power battery.

[0041] In the DC charging system of the present invention, before vehicle charging, the control module controls the first switch to open and the second switch to close, so that the low-voltage power-on circuit is turned on and the charging circuit is turned off, realizing the heating of the cable of the charging gun; then, the control module controls the first switch to close and the second switch to open, so that the charging circuit is turned on and the low-voltage power-on circuit is turned off, realizing the charging of the battery, and solving the problem of inconvenient operation caused by the stiffness of the charging gun cable before vehicle charging.

[0042] To facilitate users to preheat the cable of the charging gun as needed, in this system, the control module is also used to wirelessly communicate with the user's handheld terminal or PC terminal, receive the control instructions sent by the user, and control the on / off of the low-voltage power-on circuit according to the instructions to realize the heating of the cable of the charging gun.

[0043] In this system, the purpose of setting a single-phase rectification module (single-phase AC / DC) is to generate a constant large current (such as 250A) in the circuit. Since the impedance in the circuit is small, a single-phase AC / DC is required to generate a small voltage to generate a constant large current (250A). The original three-phase AC / DC cannot achieve this function, so an additional single-phase AC / DC that can output a small voltage and a large current is added.

[0044] The reason for the small impedance (total impedance) in the circuit is as follows: in order for the temperature rise of the contact resistance between the power pin of the charging gun and the power socket of the charging socket to reach a certain value in a short time, the set resistor R must be small, and at the same time, the contact resistance between the pin and the socket is also small. Then, the total resistance of the circuit is small.

[0045] For example, for the output terminal of the single-phase AC / DC, I = U / R. Here, to generate a constant large current of 250A, that is, 250A = U / R0. Here, R0 is the sum of the resistance of the gun line, the contact resistance of C1 and C2, and the set resistor R. R is in the milliohm level. If R0 is 100 milliohms at this time, then the single-phase AC / DC needs to generate a voltage U = 250A * 0.1Ω = 25V, that is, this single-phase AC / DC needs to achieve the ability to output 25V and 250A.

[0046] In addition to realizing the heating function of the charging gun cable, the above-mentioned low-voltage power-on circuit can also realize another function, that is, the charging gun life prediction function. When the cable does not need to be heated, for example, in summer when it will not cause the cable to be stiff, or during winter when the temperature is greater than the set threshold (such as 10°C), the low-voltage and large-current signals generated in the low-voltage power-on circuit can be used to monitor the temperature rise after the pin and the socket are in contact, and determine whether the temperature rise is too large, so as to predict the life of the charging gun.

[0047] For example, make the low-voltage power-on circuit conductive and the charging circuit disconnected, control the single-phase rectifier module to output a current of 250 A, and maintain the duration t = 60 S or 30 S (seconds). The control module obtains the temperature data collected by the temperature sensor in real time, and judges the temperature rise of the power pin within the time period t based on the real-time collected temperature. If the temperature rise of the power pin of the charging gun within this time period is greater than the set heat value, such as 40 K, it is determined that the life of the charging gun has expired, and a warning prompt is given to remind the customer to repair and replace the charging gun.

[0048] In the DC charging system of the present invention, the reason why it can relatively reliably predict the expiration life of the charging gun is that in the low-voltage power-on circuit, after the power pin C1 and the power socket C2 are connected, a contact resistance (i.e., equivalent resistance) is formed. When current passes through this contact resistance, heat will be generated, and the greater the contact resistance, the more heat is generated, and the worse the matching effect of the charging pin and the socket. Therefore, this system determines the integrity of the charging pin and the socket by judging the generated heat, makes a preliminary judgment on the life of the charging gun, and enables the user to timely repair the charging gun to avoid problems such as reduced charging efficiency and ablation of the charging gun and the charging socket.

[0049] In this embodiment, the control module's on-off control of the low-voltage power-on circuit can be time-controlled triggering, that is, when the charger is idle, according to the system timing, it is automatically triggered at regular intervals to close the second contactor and open the first contactor for a life detection of the charging gun; as another implementation, it can also perform a life detection of the charging gun before and after vehicle charging respectively.

[0050] Embodiment of the cable heating system:

[0051] This embodiment proposes a cable heating system for a charging gun, as Figure 1 shown, mainly including a low-voltage power-on circuit formed by sequentially connecting a single-phase rectifier module, the switch K2 of a DC contactor, a charging gun, and a charging socket, and a connection resistor R is provided on this circuit, and both ends of this connection resistor are connected between the two sockets C2 of the charging socket.

[0052] Furthermore, this cable heating system also includes a control module, which controls the coil of the above-mentioned DC contactor, and is also communicatively connected to a temperature sensor built in the power pin C1 of the charging gun for real-time monitoring of the heating temperature after the pin and the socket are in contact, sending the temperature data to the control module, and the control module judges whether the duration Δt of the temperature rise at this temperature being greater than a certain set value is greater than the set duration. If it is greater, stop heating the cable and control the switch K2 of the DC contactor to open.

[0053] The control module is also used for wireless communication connection with the user's handheld terminal or PC terminal, to receive the control instructions sent by the user, and control the on / off of the low-voltage power-on circuit according to the instructions, so as to realize the scheduled heating of the cable of the charging gun.

[0054] In addition to realizing the heating function of the charging gun cable, the above-mentioned low-voltage power-on circuit can also realize the prediction function of the charging gun life. Since the working principle of the cable heating system and both functions have been clearly and completely introduced in the DC charging system embodiment, they will not be elaborated in this embodiment.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications or equivalent replacements can still be made to the specific embodiments of the present invention, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention should be covered by the protection scope of the claims of the present invention.

Claims

1. A DC charging system for an electric vehicle, characterized in that, It includes a charger, as well as a control module, a three-phase rectifier charging module, a first switch, and a charging gun arranged in the charger. Among them, the AC side of the three-phase rectifier charging module is used to connect to the power supply, and the DC side of the three-phase rectifier charging module, the first switch, and the charging gun are connected in sequence to form a charging circuit; on the charger body, there is a charging socket, and there are two jacks on the charging socket for correspondingly connecting two pins on the charging gun. Temperature sensors are built in the pins to detect the heating temperature after the pins and jacks are in contact. It further includes a single-phase rectifier module and a second switch. The single-phase rectifier module is connected to the second switch to form a low-voltage branch, and this low-voltage branch is connected in parallel to the high-voltage branch formed by the connection of the three-phase rectifier charging module and the first switch; and a resistor is connected between the two jacks, and the low-voltage branch is connected in sequence through the pins of the charging gun, the jacks of the charging socket, and the resistor to form a low-voltage energized circuit. The control module is controllably connected to the first switch and the second switch, and is used to control the conduction of the charging circuit by using the first switch to realize vehicle charging through the charging circuit; and before vehicle charging, it controls the conduction of the low-voltage energized circuit by using the second switch to realize the heating of the cable on the charging gun through the low-voltage energized circuit. The control module is communicatively connected to the temperature sensor, and is used to, when the charger is idle, control the conduction of the low-voltage energized circuit by using the second switch, and judge the temperature rise of the pin within a set time period according to the temperature collected by the temperature sensor in real time. If the temperature rise of the charging gun pin within the set time period is greater than the set heat value, it is determined that the life of the charging gun has expired.

2. The DC charging system for an electric vehicle according to claim 1, wherein, The control module is used to control the cable heating time of the charging gun according to the temperature rise of the heating temperature.

3. The DC charging system of the electric vehicle according to claim 1, characterized in that, The control module is connected to the coil of the first contactor and the coil of the second contactor. The first switch is the switch of the first contactor, and the second switch is the switch of the second contactor.

4. The DC charging system for an electric vehicle according to claim 1, wherein The control module is also used to be wirelessly communicatively connected to the user's handheld terminal or PC terminal, and is used to receive the control instructions sent by the user to perform reserved charging of the vehicle, and control the conduction of the low-voltage energized circuit before vehicle charging to realize the heating of the cable of the charging gun.

5. A cable heating system for a charging gun, characterized in that, It includes a single-phase rectifier module, a DC switch, a charging gun and a charging socket. The single-phase rectifier module, the DC switch, the pins of the charging gun and the jacks of the charging socket are connected in sequence to form a low-voltage energized circuit, and a connecting resistor is connected in series on this circuit. The two ends of the connecting resistor are connected between the two jacks of the charging socket; temperature sensors are built in the pins to detect the heating temperature after the pins and jacks are in contact. It further includes a control module. The control module is controllably connected to the DC switch and is used to control the DC switch, thereby realizing the on-off control of the low-voltage energized circuit and realizing the heating of the cable on the charging gun through the low-voltage energized circuit. The described control module is communicatively connected to the temperature sensor and is used to control the conduction of the low-voltage power-on circuit by means of a DC switch when the charger is idle, and to judge the temperature rise of the pin within a set time period according to the temperature collected by the temperature sensor in real time. If the temperature rise of the charging gun pin within the set time period is greater than the set heat value, it is determined that the life of the charging gun has expired.

6. The cable heating system of the charging gun according to claim 5, characterized in that, The described control module is used to control the cable heating time of the charging gun according to the temperature rise of the heating temperature.

7. The cable heating system of the charging gun according to claim 5, wherein, The control module is connected to the coil of a DC contactor, and the DC switch is the switch of the DC contactor.

8. The cable heating system of the charging gun according to claim 5, characterized in that, The control module is also used to be wirelessly communicatively connected to the user's handheld terminal or PC terminal, receive the control instructions sent by the user, perform reserved charging of the vehicle, and control the conduction of the low-voltage power-on circuit before vehicle charging to achieve cable heating of the charging gun.

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