Low-temperature heating system and method for low-voltage battery of electric vehicle and electric vehicle

Abstract

The present invention provides a low-temperature heating system and method for low-voltage batteries in electric vehicles, as well as an electric vehicle, to address the problem of low charging efficiency of low-voltage batteries at low temperatures. The low-temperature heating method for low-voltage batteries in electric vehicles includes: acquiring vehicle status information in real time; determining whether the low-voltage battery needs to be heated during charging based on the vehicle status information; and, if heating is required, selecting whether to heat the low-voltage battery using waste heat from the electric drive or using a PTC electric heater.

Description

Technical Field

[0001] The present invention relates to the field of heating low-voltage batteries for automobiles, and in particular to a low-temperature heating system and method for a low-voltage battery for an electric vehicle, and the electric vehicle. Background Art

[0002] At low temperatures, automotive power batteries are limited by their own chemical properties, and there are problems such as reduced power battery discharge, reduced charge / discharge current, and long charging time. Like power batteries, low-voltage batteries also have the problems of reduced available power, slow charging at low temperatures, and reduced discharge current due to reduced battery voltage. Therefore, CN215299358U / "A Battery Constant Temperature Graphene Heating Device" provides a low-temperature heating technology for increasing the voltage and discharge current of low-voltage batteries to help start fuel vehicles. However, the direct reason why low-voltage batteries cannot provide sufficient discharge current is the reduction in available power caused by the difficulty of charging at low temperatures. Therefore, how to ensure the battery charging rate at low temperatures is the key to solving this problem. Summary of the Invention

[0003] The present invention provides a low-temperature heating system and method for a low-voltage battery of an electric vehicle and the electric vehicle, for solving the problem of low charging efficiency of the low-voltage battery at low temperatures.

[0004] The technical solution of the present invention is:

[0005] The present invention provides a low-temperature heating method for a low-voltage battery of an electric vehicle, comprising:

[0006] Get vehicle status information in real time;

[0007] Determining whether the low-voltage battery needs to be heated when charging the low-voltage battery based on vehicle status information;

[0008] If the low-voltage battery needs to be heated when it is charged, choose to use the waste heat of the electric drive to heat the low-voltage battery or use the electric heater PTC to heat the low-voltage battery.

[0009] Preferably, the step of selecting to use the waste heat of the motor to heat the low-voltage battery or to use the electric heater PTC to heat the low-voltage battery includes:

[0010] Based on the vehicle's high-voltage power-on status, the low-voltage battery water outlet temperature, the electric drive water outlet temperature, and the electric drive operating status, determine whether the water heating conditions for using the electric drive waste heat to heat the low-voltage battery are met;

[0011] If the water heating conditions for using the waste heat from the electric drive to heat the low-voltage battery are met, choose to use the waste heat from the electric drive to heat the low-voltage battery;

[0012] If the water heating conditions for heating the low-voltage battery using the waste heat from the electric drive are not met, the electric heating conditions for heating the low-voltage battery using the electric heater PTC are determined based on the vehicle's high-voltage power-on status, the low-voltage battery outlet water temperature, the electric drive outlet water temperature, and the electric drive operating status.

[0013] If the electric heating conditions for heating the low-voltage battery using the electric heater PTC are met, the electric heater PTC is selected to heat the low-voltage battery.

[0014] Preferably, the step of selecting to utilize electric drive waste heat to heat the low-voltage battery includes:

[0015] Control the water heating motor in the water heating circuit to turn on, control the electric heater PTC in the water heating circuit to turn off, and control the water cooling motor in the water cooling circuit to turn off;

[0016] The water heating circuit is a circuit that transports waste heat from the electric drive to the location of the low-voltage battery;

[0017] The water cooling circuit is a circuit for cooling the electric drive;

[0018] The water cooling circuit and the water heating circuit share the branch where the electric drive is located.

[0019] Preferably, the step of selecting to use an electric heater PTC to heat the low-voltage battery includes:

[0020] The water heating motor in the water heating circuit is controlled to be turned off, and the electric heater PTC in the water heating circuit is controlled to be turned on.

[0021] Preferably, if the vehicle high voltage is powered on, the electric drive is in operation, and the low voltage battery outlet water temperature is less than or equal to the electric drive outlet water temperature, it is determined that the water heating conditions for utilizing the electric drive waste heat to heat the low voltage battery are met;

[0022] If the vehicle is powered on at high voltage and the electric drive is turned off, it is determined that the electric heating conditions for heating the low-voltage battery using the electric heater PTC are met.

[0023] Preferably, the method further comprises:

[0024] When the heating temperature of the low-voltage battery using the waste heat of the electric drive or the electric heater PTC reaches a preset temperature, heating of the low-voltage battery is stopped.

[0025] Preferably, when the outlet water temperature of the low-voltage battery is lower than a preset temperature, it is determined that the low-voltage battery needs to be heated when charging the low-voltage battery.

[0026] The present invention also provides a low-temperature heating system for a low-voltage battery of an electric vehicle for implementing the above-mentioned low-temperature heating method for a low-voltage battery of an electric vehicle, the system comprising:

[0027] A thermal management controller, a low-voltage battery, an electric drive, a water heating circuit connecting the low-voltage battery and the electric drive in series, and a water cooling circuit for cooling the electric drive, wherein the water cooling circuit and the water heating circuit share a branch circuit where the electric drive is located;

[0028] The water heating circuit also includes an electric heater PTC that relies on power from the power battery to heat the low-voltage battery;

[0029] The thermal management controller determines whether the low-voltage battery needs to be heated when charging the low-voltage battery based on the vehicle status information;

[0030] When it is determined that the low-voltage battery needs to be heated when charging, the thermal management controller controls the water cooling circuit and the water heating circuit to heat the low-voltage battery using the waste heat of the electric drive or using the electric heater PTC to heat the low-voltage battery.

[0031] Preferably, the water heating circuit comprises:

[0032] An electric drive, a water heating motor, and a water tank wrapped around a low-voltage battery are connected in series; the electric heater PTC is arranged in the water tank; the water heating motor and the electric heater PTC are both electrically connected to the thermal management controller;

[0033] The water cooling circuit comprises:

[0034] An electric drive, a water-cooled motor and a kettle are sequentially connected in series, wherein the water-cooled motor is electrically connected to the thermal management controller;

[0035] The thermal management controller controls the water heating motor to be turned on, the electric heater PTC to be turned off, and the water cooling motor to be turned off, so as to utilize the waste heat of the electric drive to heat the low-voltage battery;

[0036] The thermal management controller controls the water heating motor to be turned off and the electric heater PTC to be turned on, thereby utilizing the electric heater PTC to heat the low-voltage battery.

[0037] The present invention also provides an electric vehicle, comprising the above-mentioned electric vehicle low-voltage battery low-temperature heating system.

[0038] The beneficial effects of the present invention are:

[0039] If the low-voltage battery requires heating during charging, the system will choose to utilize either the electric drive's waste heat or a PTC heater, depending on actual needs and system status. Using the electric drive's waste heat to heat the low-voltage battery fully utilizes the heat without wasting vehicle power. While using the PTC to heat the low-voltage battery, the running electric drive can also be cooled. Heating the low-voltage battery improves charging efficiency by utilizing the vehicle's power battery's energy, reducing charging time. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a schematic diagram of the system in this embodiment;

[0041] Figure 2 Schematic diagram of the method in this embodiment. DETAILED DESCRIPTION

[0042] like Figure 1 In this embodiment, to improve the charging efficiency of the electric vehicle's low-voltage battery 2, the low-voltage battery 2 is heated before charging in a low-temperature environment. To this end, this embodiment provides an electric vehicle low-voltage battery low-temperature heating system. The system comprises a thermal management controller, a low-voltage battery 2, an electric drive 1, and a water heating circuit and a water cooling circuit for heat transfer.

[0043] In this embodiment, when the outlet water temperature of the low-voltage battery is lower than a preset temperature (eg, 20° C.), it is determined that the low-voltage battery 2 needs to be heated when charging the low-voltage battery 2 .

[0044] The electric drive 1 mentioned above refers to a circuit including a motor controller and a motor. When the motor is running, a large amount of heat is generated. Most of the waste heat of the electric drive described in this embodiment comes from the heat dissipated during the operation of the motor.

[0045] The water heating and water cooling circuits share the same branch as the electric drive 1. The low-voltage battery 2 is located in the water heating circuit. The electric drive 1 is located in both the water heating and water cooling circuits. The water heating circuit transfers waste heat from the electric drive to the low-voltage battery 2, while the water cooling circuit cools the electric drive 1.

[0046] An electric heater PTC5 for electrically heating the low-voltage battery 2 is also arranged in the water heating circuit. The electric heater PTC5 is powered by the power battery of the vehicle.

[0047] At this point, the thermal management controller controls the relevant electrical components in the water heating circuit, the electric heater PTC5, and the relevant electrical components in the water cooling circuit, enabling the system to form a circuit that uses waste heat from the electric drive to heat the low-voltage battery 2, a circuit that uses the electric heater PTC5 to heat the low-voltage battery 2, and a circuit that cools the electric drive 1. The specific formation of these circuits is explained below.

[0048] like Figure 1 In this embodiment, the water heating circuit specifically includes: a water-cooled motor 6 connected in series, a water tank 4 that wraps the low-voltage battery 2, and an electric drive 1. The electric heater PTC 5 is arranged in the water tank 4. Therefore, when it is necessary to use the waste heat of the electric drive to heat the low-voltage battery 2, the thermal management controller controls the water heating motor 3 to turn on and the electric heater PTC5 to turn off. Then, the waste heat of the electric drive is transferred to the water tank 4 through the water heating motor 3, and the heat entering the water tank 4 starts to heat the wrapped low-voltage battery 2. At the same time, in this process, the temperature of the liquid after the high-temperature medium pumped in by the water heating motor 3 and the low-temperature medium in the water tank 4 are mixed is lower than the water outlet temperature of the electric drive. The temperature of the liquid that heats the low-voltage battery 2 becomes even lower, and then flows back to the electric drive 1 to achieve the heat dissipation effect of the electric drive 1. When the electric heater PTC5 is needed to heat the low-voltage battery 2, the thermal management controller controls the water heating motor 3 to turn off and controls the electric heater PTC5 to turn on. At this time, the water heating circuit cannot form a through circuit. The water tank 4 serves as a closed container for storing the medium. The medium in the water tank 4 is heated by the electric heater PTC5 inside it to achieve heating of the low-voltage battery 2. At this time, whether the electric drive 1 is running or not will not affect the heating effect of the low-voltage battery 2.

[0049] like Figure 1 In this embodiment, the water cooling circuit specifically includes: an electric drive 1, a water-cooled motor 6, and a kettle 7 connected in series. In this embodiment, how should the thermal management controller select which heating method to use to heat the low-voltage battery 2? This selection depends on the low-voltage battery water outlet temperature and the electric drive water outlet temperature. Specifically, in this embodiment, when it is determined that the low-voltage battery 2 needs to be heated during charging, if:

[0050] 1) The whole vehicle is powered on with high voltage;

[0051] 2) Electric drive 1 is in operation;

[0052] 3) The outlet water temperature of the low-voltage battery is less than or equal to the outlet water temperature of the electric drive;

[0053] When the low-voltage battery outlet water temperature is lower than the electric drive outlet water temperature, it indicates that the electric drive has a large amount of waste heat, which is sufficient to heat the low-voltage battery 2. In this state, the thermal management controller selects to use the electric drive waste heat to heat the low-voltage battery 2. When the low-voltage battery outlet water temperature is equal to the electric drive outlet water temperature, water heating is still used for heating because the temperature of the electric drive rises rapidly during operation. However, the heating efficiency is low for a short period of time during the initial heating process. After the electric drive temperature rises rapidly, the heating rate of the low-voltage battery will increase rapidly.

[0054] In addition, in this embodiment, when it is determined that the low-voltage battery 2 needs to be heated during charging, if:

[0055] 1) The whole vehicle is powered on with high voltage;

[0056] 2) Electric drive 1 is in the off state;

[0057] At this time, since the electric drive 1 is not started and cannot generate heat, the only option is to use the electric heater PTC5 to heat the low-voltage battery 2.

[0058] Therefore, based on the above description, in this embodiment, a scenario is provided for heating the low-voltage battery 2 by utilizing waste heat from the electric drive; and a scenario is provided for heating the low-voltage battery 2 by utilizing the electric heater PTC5.

[0059] After heating the low-voltage battery 2 in the above manner, the temperature of the low-voltage battery 2 continues to rise, which can improve the charging efficiency of the low-voltage battery 2. In this embodiment, when the heating temperature of the low-voltage battery 2 using the waste heat of the electric drive or the electric heater PTC5 reaches the preset temperature, the heating of the low-voltage battery 2 is stopped (stopping heating specifically means turning off the electric heater PTC5 or turning off the water heating motor 3, so that the circuit for heating the low-voltage battery 2 cannot form a path). In this embodiment, the preset temperature range can be set to between 20°C and 30°C, and the optimal value of the preset temperature can be set to 25°C.

[0060] The embodiment of the present invention utilizes the above-mentioned system. When it is determined that the low-voltage battery 2 needs to be heated during charging, it will choose to use the waste heat of the electric drive to heat the low-voltage battery 2 or use the electric heater PTC5 to heat the low-voltage battery 2 according to actual needs and system status, thereby improving the charging efficiency of the low-voltage battery 2 and reducing the charging time of the low-voltage battery 2. When using the waste heat of the electric drive to heat the low-voltage battery 2, the waste heat of the electric drive can be fully utilized without wasting the power of the entire vehicle; while using the PTC to heat the low-voltage battery 2, the electric drive 1 in operation can be cooled. After heating the low-voltage battery 2, the charging efficiency when using the energy of the vehicle's power battery to charge the low-voltage battery 2 will be improved, reducing the charging time of the low-voltage battery 2.

[0061] like Figure 2 In this embodiment, the above system is used to form a low-temperature heating method for the low-voltage battery 2 of an electric vehicle, and the method includes:

[0062] Step S1, obtaining vehicle status information in real time.

[0063] The vehicle status information includes: the high-voltage power-on status of the vehicle received from the vehicle system, the low-voltage battery water outlet temperature detected by the temperature sensor set at the low-voltage battery water outlet, the electric drive water outlet temperature detected by the temperature sensor set at the electric drive water outlet, and the electric drive working status.

[0064] Step S2: determining whether the low-voltage battery 2 needs to be heated when charging the low-voltage battery 2 according to the vehicle state information.

[0065] In this embodiment, when the outlet water temperature of the low-voltage battery is lower than a preset temperature (eg, 20° C.), it is determined that the low-voltage battery 2 needs to be heated when charging the low-voltage battery 2 .

[0066] Step S3: If the low-voltage battery 2 needs to be heated when charging, the low-voltage battery 2 is heated by utilizing the waste heat of the electric drive or by utilizing the electric heater PTC5.

[0067] Step S3 specifically includes: judging whether the water heating condition for heating the low-voltage battery 2 by utilizing the waste heat of the electric drive is met based on the high-voltage power-on state of the vehicle, the water outlet temperature of the low-voltage battery, the water outlet temperature of the electric drive, and the working state of the electric drive;

[0068] Step S301: If the water heating conditions for using the waste heat of the electric drive to heat the low-voltage battery 2 are met, then the waste heat of the electric drive is selected to heat the low-voltage battery 2; the control steps for selecting the waste heat of the electric drive to heat the low-voltage battery 2 are: control the water heating motor 3 in the water heating circuit to turn on, control the electric heater PTC5 in the water heating circuit to turn off, and control the water cooling motor 6 in the water cooling circuit to turn off.

[0069] If the vehicle high voltage is powered on, the electric drive 1 is in operation, and the low-voltage battery outlet water temperature is less than or equal to the electric drive outlet water temperature, it is determined that the water heating conditions for using the electric drive waste heat to heat the low-voltage battery 2 are met.

[0070] In step S302, if the water heating conditions for heating the low-voltage battery 2 using the waste heat of the electric drive are not met, then based on the high-voltage power-on status of the vehicle, the low-voltage battery water outlet temperature, the electric drive water outlet temperature, and the working status of the electric drive 1, it is determined whether the electric heating conditions for heating the low-voltage battery 2 using the electric heater PTC5 are met.

[0071] If the high voltage of the vehicle is powered on and the electric drive 1 is turned off, it is determined that the electric heating condition for heating the low-voltage battery 2 by using the electric heater PTC 5 is met.

[0072] Step S303, if the electric heating conditions for using the electric heater PTC5 to heat the low-voltage battery 2 are met, then the electric heater PTC5 is selected to heat the low-voltage battery 2; the control steps for selecting the electric heater PTC5 to heat the low-voltage battery 2 are specifically: controlling the water heating motor 3 in the water heating circuit to turn off, and controlling the electric heater PTC5 in the water heating circuit to turn on.

[0073] Step S4: When the heating temperature of the low-voltage battery 2 using the electric drive waste heat or the electric heater PTC 5 reaches a preset temperature, the heating of the low-voltage battery 2 is stopped.

[0074] The above method of this embodiment, when determining that the low-voltage battery 2 needs to be heated during charging, will choose to use the waste heat of the electric drive to heat the low-voltage battery 2 or use the electric heater PTC5 to heat the low-voltage battery 2 according to actual needs and system status, thereby improving the charging efficiency of the low-voltage battery 2 and reducing the charging time of the low-voltage battery 2. When using the waste heat of the electric drive to heat the low-voltage battery 2, the waste heat of the electric drive can be fully utilized without wasting the power of the entire vehicle; while using the electric heater PTC5 to heat the low-voltage battery 2, the electric drive 1 in operation can be cooled. After heating the low-voltage battery 2, the charging efficiency when using the energy of the power battery of the entire vehicle to charge the low-voltage battery 2 will be improved, reducing the charging time of the low-voltage battery 2.

[0075] Although explained in detail with reference to a limited number of embodiments, the present invention is not limited to the applications set forth in the specification and embodiments, but is fully applicable to a wide variety of fields suitable for the present invention. Further modifications, additions, and substitutions will readily occur to those skilled in the art, and the present invention should not be construed as being limited by the foregoing description without departing from the general concept defined by the claims and their equivalents.

Claims

1. A low-temperature heating method for a low-voltage battery of an electric vehicle, characterized in that: include: Get vehicle status information in real time; Determining whether the low-voltage battery needs to be heated when charging the low-voltage battery based on vehicle status information; When the outlet water temperature of the low-voltage battery is lower than a preset temperature, it is determined that the low-voltage battery needs to be heated when charging the low-voltage battery; If the low-voltage battery needs to be heated when it is charged, choose to use the waste heat of the electric drive or use the electric heater PTC to heat the low-voltage battery; The steps for selecting whether to use the motor waste heat or the electric heater PTC to heat the low-voltage battery include: Based on the vehicle's high-voltage power-on status, the low-voltage battery water outlet temperature, the electric drive water outlet temperature, and the electric drive operating status, determine whether the water heating conditions for using the electric drive waste heat to heat the low-voltage battery are met; If the water heating conditions for using the waste heat from the electric drive to heat the low-voltage battery are met, choose to use the waste heat from the electric drive to heat the low-voltage battery; If the water heating conditions for heating the low-voltage battery using the waste heat from the electric drive are not met, the electric heating conditions for heating the low-voltage battery using the electric heater PTC are determined based on the vehicle's high-voltage power-on status, the low-voltage battery outlet water temperature, the electric drive outlet water temperature, and the electric drive operating status. If the electric heating conditions for heating the low-voltage battery by using the electric heater PTC are met, the electric heater PTC is selected to heat the low-voltage battery; After heating the low-voltage battery, the energy of the vehicle's power battery is used to charge the low-voltage battery; The steps for using waste heat from the electric drive to heat the low-voltage battery include: Control the water heating motor in the water heating circuit to turn on, control the electric heater PTC in the water heating circuit to turn off, and control the water cooling motor in the water cooling circuit to turn off; The water heating circuit is a circuit that transports waste heat from the electric drive to the location of the low-voltage battery; The water cooling circuit is a circuit for cooling the electric drive; The water cooling circuit and the water heating circuit share the branch where the electric drive is located.

2. The low-temperature heating method for a low-voltage battery of an electric vehicle according to claim 1, characterized in that: The steps for selecting an electric heater PTC to heat the low-voltage battery include: Control the water heating motor in the water heating circuit to turn off, and control the electric heater PTC in the water heating circuit to turn on; The water heating circuit is a circuit that transports waste heat from the electric drive to the location of the low-voltage battery.

3. The low-temperature heating method for a low-voltage battery of an electric vehicle according to claim 1, characterized in that: If the vehicle's high voltage is powered on, the electric drive is in operation, and the low-voltage battery outlet water temperature is less than or equal to the electric drive outlet water temperature, then the water heating conditions for utilizing the electric drive waste heat to heat the low-voltage battery are met; If the vehicle is powered on at high voltage and the electric drive is turned off, it is determined that the electric heating conditions for heating the low-voltage battery using the electric heater PTC are met.

4. The low-temperature heating method for a low-voltage battery of an electric vehicle according to claim 1, characterized in that: The method further comprises: When the heating temperature of the low-voltage battery using the waste heat of the electric drive or the electric heater PTC reaches a preset temperature, heating of the low-voltage battery is stopped.

5. A low-temperature heating system for a low-voltage battery of an electric vehicle for implementing the low-temperature heating method for a low-voltage battery of an electric vehicle according to any one of claims 1 to 4, characterized in that: The system comprises: A thermal management controller, a low-voltage battery, an electric drive, a water heating circuit connecting the low-voltage battery and the electric drive in series, and a water cooling circuit for cooling the electric drive, wherein the water cooling circuit and the water heating circuit share a branch circuit where the electric drive is located; The water heating circuit also includes an electric heater PTC that relies on power from the power battery to heat the low-voltage battery; The thermal management controller determines whether the low-voltage battery needs to be heated when charging the low-voltage battery based on the vehicle status information; When it is determined that the low-voltage battery needs to be heated when charging, the thermal management controller controls the water cooling circuit and the water heating circuit to heat the low-voltage battery using the waste heat of the electric drive or using the electric heater PTC to heat the low-voltage battery.

6. The low-temperature heating system for low-voltage batteries of electric vehicles according to claim 5, characterized in that: The water heating circuit includes: An electric drive, a water heating motor, and a water tank wrapped around a low-voltage battery are connected in series; the electric heater PTC is arranged in the water tank; the water heating motor and the electric heater PTC are both electrically connected to the thermal management controller; The water cooling circuit comprises: An electric drive, a water-cooled motor and a kettle are sequentially connected in series, wherein the water-cooled motor is electrically connected to the thermal management controller; The thermal management controller controls the water heating motor to be turned on, the electric heater PTC to be turned off, and the water cooling motor to be turned off, so as to utilize the waste heat of the electric drive to heat the low-voltage battery; The thermal management controller controls the water heating motor to be turned off and the electric heater PTC to be turned on, thereby utilizing the electric heater PTC to heat the low-voltage battery.

7. An electric vehicle, characterized in that: It includes the low-temperature heating system for a low-voltage battery of an electric vehicle as described in claim 5 or 6.

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