Power battery heating system, heating method and vehicle

Abstract

The invention discloses a power battery heating system, a heating method and a vehicle. The heating system comprises a range extender, a heat exchange circulation loop and a controller. The heat exchange circulation loop comprises an engine cooling liquid circulation loop, a first water pump, a PTC heater, a heat exchanger, a second water pump and a power battery. And the controller is used for controlling the power battery heating system to heat the power battery. The engine cooling liquid is heated by waste heat of the engine through the engine cooling liquid circulation loop, heat exchange is carried out on the heated engine cooling liquid and the power battery cooling liquid through the heat exchanger, the power battery is heated through the heated power battery cooling liquid, and when the temperature of the power battery cannot meet the requirement, the engine cooling liquid is heated through the heat exchanger. And the heated engine cooling liquid is heated again through the PTC heater. The energy utilization efficiency of the engine and the whole vehicle can be improved, intervention of a PTC heater is reduced, the driving range of the range-extended hybrid electric vehicle is increased, and meanwhile the heating speed can be effectively increased.

Description

Technical Field

[0001] The present invention belongs to the technical field of new energy vehicles, and more specifically, relates to a power battery heating system, a heating method and a vehicle. Background Art

[0002] For extended-range hybrid vehicles, when the ambient temperature is too low, the activity of the chemical substances inside the power battery decreases, the chemical reaction rate slows down, the available capacity of the battery decreases, and the internal polarization of the battery increases, and the energy storage efficiency decreases. At the same time, if the power battery is directly charged in a low-temperature environment, it is easy to cause irreversible lithium crystallization in the battery cell, and lithium dendrites are easy to pierce the internal diaphragm, causing a short circuit between the positive and negative electrodes of the battery, affecting the safety performance of the battery. Therefore, when the external ambient temperature is low, the power battery pack needs to be heated to keep it within a suitable temperature range to ensure normal charging and discharging of the power battery.

[0003] In low temperature environments, the heat generation power of power batteries is low and cannot meet their own heating needs, so additional heating methods are required to heat them. Currently, for hybrid vehicles, when the temperature of the power battery is too low, it is generally heated by electrically heating the coolant. At present, the commonly used method for heating the power battery of hybrid vehicles is mainly hydrothermal PTC (Positive Temperature Coefficient) heater heating. The working principle of this method is to achieve temperature regulation of cooling liquid or air through the temperature control characteristics of PTC elements. By connecting a hydrothermal heater PTC in series in the thermal management coolant circulation loop, the PTC generates heat after being energized to exchange heat with the power battery coolant. The power battery coolant transfers heat to the power battery cell through heat conduction and heat convection to achieve heating of the power battery until the power battery is heated to a suitable operating temperature, ensuring that the power battery can be charged and discharged at a suitable temperature when the ambient temperature is low. The heating power and temperature of the PTC are adjusted by controlling the current flowing through the PTC. The hydrothermal PTC heating power battery pack has the characteristics of self-regulation of power and relatively mature technology, but PTC heating also has obvious disadvantages:

[0004] (1) The hydrothermal PTC heater requires a large current to generate sufficient heat, so it consumes a lot of electricity during the heating process, affecting the vehicle's driving range;

[0005] (2) Due to the positive change characteristics of the water-heated PTC heater, there may be excessive overshoot during cold start, resulting in inaccurate temperature control;

[0006] (3) The hydrothermal PTC heater takes a long time to reach the required operating temperature, and the heating time is long;

[0007] (4) The hydrothermal PTC heater is composed of multiple metal parts, and most of the parts are planar, which are easily oxidized and damaged at high temperatures, so the service life is short;

[0008] Therefore, the PTC heating method will consume a certain amount of electrical energy, resulting in a shortened vehicle range. In addition, due to the limitation of battery power, the heating rate is too slow, the user has to wait for a long time, and the driving experience is poor for a long time during the initial driving.

[0009] The information disclosed in the background technology section of the present invention is only intended to deepen the understanding of the general background technology of the present invention, and should not be regarded as acknowledging or suggesting in any form that the information constitutes the prior art already known to those skilled in the art. Summary of the invention

[0010] The purpose of the present invention is to propose a power battery heating system, a heating method and a vehicle, so as to solve the problems of large power consumption when heating the power battery pack of an extended-range hybrid vehicle in an extremely low temperature environment, affected vehicle mileage, slow heating and user complaints. The present invention provides the heat generated when the range extender engine is running to the power battery pack for heating. While ensuring that the power battery pack is heated to a suitable operating temperature, the vehicle's waste heat resources are fully and reasonably utilized to improve the energy utilization efficiency of the engine and the entire vehicle; and the intervention of the hydrothermal PTC electric heater is reduced, thereby reducing a certain amount of energy consumption, increasing the mileage of the extended-range hybrid vehicle, and at the same time being able to effectively improve the heating speed.

[0011] To achieve the above objectives, the present invention provides a power battery heating system, a heating method and a vehicle.

[0012] According to a first aspect of the present invention, a power battery heating system is provided, comprising:

[0013] Range extender, including engine and ISG motor;

[0014] A heat exchange circulation loop, comprising an engine coolant circulation loop, a first water pump, a PTC heater, a heat exchanger, a second water pump and a power battery; a water outlet of the engine coolant circulation loop is communicated with a water inlet of the first water pump through a first three-way valve, a water outlet of the first water pump is communicated with a water inlet of the PTC heater, a water outlet of the PTC heater is communicated with a hot water inlet of the heat exchanger through a second three-way valve, and a hot water outlet of the heat exchanger is communicated with a water inlet of the engine coolant circulation loop through a third three-way valve;

[0015] A first flow chamber for circulating power battery coolant is provided inside the power battery, a water inlet of the first flow chamber is communicated with a water outlet of the second water pump, a water outlet of the flow chamber is connected with a cold water inlet of the heat exchanger, and a cold water outlet of the heat exchanger is connected with a water inlet of the second water pump;

[0016] The controller is used to control the power battery heating system to heat the power battery in an engine waste heat heating mode or a combined heating mode.

[0017] Optionally, the engine coolant circulation loop comprises:

[0018] Cylinder block water jacket, cylinder head water jacket, thermostat and third water pump;

[0019] The cylinder water jacket and the cylinder head water jacket are in communication, the water inlet of the thermostat is connected to the water outlets of the cylinder water jacket and the cylinder head water jacket respectively, the water outlet of the thermostat is connected to the water inlet of the third water pump through the first three-way valve, and the water outlet of the third water pump is connected to the water inlet of the cylinder water jacket through the third three-way valve;

[0020] The cylinder body water jacket is provided with a plurality of first water inlets and a first water outlet for communicating with the cylinder head water jacket, and the cylinder head water jacket is provided with a plurality of second water inlets and a second water outlet corresponding to the first water inlets and the first water outlet; the first water inlet is communicated with the corresponding second water outlet, and the first water outlet is communicated with the second water inlet, so as to form a second flow chamber for heating the engine coolant.

[0021] Optionally, it also includes:

[0022] The heat dissipation module, the water outlet of the PTC heater is connected to the water inlet of the heat dissipation module through a second three-way valve, and the water outlet of the heat dissipation module is connected to the water inlet of the engine coolant circulation loop.

[0023] Optionally, it also includes:

[0024] A first temperature acquisition module, used for acquiring a first temperature of the engine coolant in the engine coolant circulation loop and sending it to the controller;

[0025] The second temperature acquisition module is used to acquire the second temperature of the power battery and send it to the controller.

[0026] Optionally, the engine waste heat heating mode includes:

[0027] When the second temperature is lower than the first preset temperature threshold, the controller controls the ISG motor to start the engine with the set discharge power of the power battery, and controls the opening and closing of each channel of the first three-way valve and the third three-way valve to close the engine coolant circulation loop, and controls the third water pump to start, so that the engine coolant circulates in the engine coolant circulation loop, and heats the engine coolant in the second flow chamber by using the heat generated by the engine;

[0028] When the first temperature is higher than the second preset temperature threshold, the controller controls the opening and closing of each channel of the first three-way valve, the second three-way valve and the third three-way valve to connect the engine coolant circulation loop with the heat exchanger, and controls the start of the first water pump and the second water pump at the same time, so that the engine coolant exchanges heat with the power battery coolant in the heat exchanger, and heats the power battery in the first flow chamber by using the power battery coolant that has completed the heat exchange;

[0029] When the second temperature reaches a third set temperature threshold, the controller controls the opening and closing of each channel of the second three-way valve to disconnect the engine coolant circulation loop from the heat exchanger and connect the engine coolant circulation loop to the heat dissipation module.

[0030] Optionally, the combined heating mode includes:

[0031] When the power battery is heated by the engine waste heat heating mode for a set time and the second temperature is lower than a third set temperature threshold, the controller controls the PTC heater to heat the engine coolant flowing out of the engine coolant circulation loop until the second temperature reaches the third set temperature threshold, controls the opening and closing of each channel of the second three-way valve to disconnect the engine coolant circulation loop from the heat exchanger, connects the engine coolant circulation loop to the heat dissipation module, and controls the PTC heater to be turned off.

[0032] Optionally, after the ISG motor is started, the engine torque is calculated according to the power battery current of 0A, and when the power battery current is less than a preset first current threshold, the controller controls the main positive relay and the main negative relay of the power battery to be disconnected;

[0033] When the second temperature reaches the third set temperature threshold, the controller controls the current generated by the ISG motor to be lower than the second current threshold, and then controls the main positive relay and the main negative relay of the power battery to close.

[0034] Optionally, when the second temperature is lower than the third set temperature threshold, the controller controls the range extender to prohibit shutdown, controls the vehicle to prohibit shifting into a drive gear, and prompts the user on the dashboard that the power battery is being preheated.

[0035] According to a second aspect of the present invention, a power battery heating method is provided. Based on the power battery heating system according to any one of the first aspects, the method comprises:

[0036] collecting a first temperature of the engine coolant and a second temperature of the power battery;

[0037] When the second temperature is lower than a first preset temperature threshold, the power battery issues a heating request;

[0038] In response to the heating request, the ISG motor is started by the power battery and then the range extender is started, and the opening and closing of each channel of the first three-way valve and the third three-way valve are controlled to close the engine coolant circulation loop, and the engine coolant is heated by the heat generated by the engine;

[0039] When the first temperature is higher than a second preset temperature threshold, the first three-way valve, the second three-way valve and the third three-way valve are controlled to be on and off so that the engine coolant circulation loop is connected to the heat exchanger, and the first water pump and the second water pump are controlled to start so that the engine coolant exchanges heat with the power battery coolant in the heat exchanger;

[0040] If the second temperature reaches a third set temperature threshold within a set time, the on-off of each channel of the second three-way valve is controlled to disconnect the engine coolant circulation loop from the heat exchanger;

[0041] If the second temperature is lower than the third set temperature threshold when the set time is reached, the PTC heater is controlled to heat the engine coolant flowing out of the engine coolant circulation loop until the second temperature reaches the third set temperature threshold, the opening and closing of each channel of the second three-way valve is controlled to disconnect the engine coolant circulation loop from the heat exchanger, and the PTC heater is controlled to be turned off.

[0042] According to a third aspect of the present invention, a vehicle is provided, comprising the power battery heating system according to any one of the first aspects.

[0043] The beneficial effects of the present invention are as follows: the present invention utilizes the waste heat of the engine to heat the engine coolant through an engine coolant circulation loop, exchanges heat between the heated engine coolant and the power battery coolant through a heat exchanger, and then heats the power battery through the heated power battery coolant, and when the temperature of the power battery cannot meet the requirements, the heated engine coolant is heated again by the PTC heater to make the temperature of the power battery meet the requirements; the present invention utilizes the heat generated by the engine to heat the power battery, and while ensuring that the power battery pack is heated to a suitable operating temperature, the waste heat resources of the vehicle are fully and reasonably utilized, thereby improving the energy utilization efficiency of the engine and the entire vehicle; and the intervention of the water-heated PTC electric heater is reduced, thereby reducing a certain amount of energy consumption, increasing the driving range of the extended-range hybrid vehicle, and at the same time being able to effectively improve the heating speed.

[0044] The system of the present invention has other characteristics and advantages, which will be apparent from the drawings incorporated herein and the following detailed description, or will be described in detail in the drawings incorporated herein and the following detailed description, which together serve to explain the specific principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, in which like reference numerals generally represent like components.

[0046] Figure 1 A schematic diagram of an engine large circulation loop of a power battery heating system according to the first embodiment of the present invention is shown.

[0047] Figure 2 A schematic diagram of an engine small circulation loop of a power battery heating system according to a first embodiment of the present invention is shown.

[0048] Figure 3 A flow chart showing the steps of a power battery heating method according to embodiment 3 of the present invention is shown. DETAILED DESCRIPTION

[0049] The present invention will be described in more detail below with reference to the accompanying drawings. Although preferred embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0050] A power battery heating system according to the present invention comprises:

[0051] Range extender, including engine and ISG motor;

[0052] A heat exchange circulation loop, comprising an engine coolant circulation loop, a first water pump, a PTC heater, a heat exchanger, a second water pump and a power battery; a water outlet of the engine coolant circulation loop is connected to a water inlet of the first water pump through a first three-way valve, a water outlet of the first water pump is connected to a water inlet of the PTC heater, a water outlet of the PTC heater is connected to a hot water inlet of the heat exchanger through a second three-way valve, and a hot water outlet of the heat exchanger is connected to a water inlet of the engine coolant circulation loop through a third three-way valve;

[0053] A first flow chamber for circulating the power battery coolant is provided inside the power battery, the water inlet of the first flow chamber is connected to the water outlet of the second water pump, the water outlet of the flow chamber is connected to the cold water inlet of the heat exchanger, and the cold water outlet of the heat exchanger is connected to the water inlet of the second water pump;

[0054] The controller is used to control the power battery heating system to heat the power battery using the engine waste heat heating mode or the combined heating mode.

[0055] Specifically, the power battery heating system of the present invention is composed of a range extender, a heat exchange circulation loop and a controller. The range extender includes an engine and an ISG motor. The heat exchange circulation loop includes an engine coolant circulation loop, a first water pump, a PTC heater, a heat exchanger, a second water pump and a power battery. The water outlet of the engine coolant circulation loop is connected to the water inlet of the first water pump through a first three-way valve, the water outlet of the first water pump is connected to the water inlet of the PTC heater, the water outlet of the PTC heater is connected to the hot water inlet of the heat exchanger through a second three-way valve, and the hot water outlet of the heat exchanger is connected to the water inlet of the engine coolant circulation loop through a third three-way valve. The power battery A first flow chamber is provided inside for circulating the power battery coolant, the water inlet of the first flow chamber is connected to the water outlet of the second water pump, the water outlet of the flow chamber is connected to the cold water inlet of the heat exchanger, and the cold water outlet of the heat exchanger is connected to the water inlet of the second water pump; it can be understood that the above-mentioned connected components are connected by pipes, for example, the first three-way valve and the water inlet of the first water pump are connected by a pipe, and the water outlet of the PTC heater is connected to the third three-way valve by a pipe; some components can also be directly connected, for example, the water outlet of the engine coolant circulation loop can be directly connected to the first three-way valve. In general, the most suitable connection method can be selected according to actual conditions.

[0056] The present invention first provides power to the ISG machine through a power battery. After the ISG motor is started, it drives the engine to start. After the engine is started, heat is generated. By controlling the on-off of each passage of the first three-way valve and the second three-way valve, that is, the passage connected to the first three-way valve and the first water pump, and the passage connected to the second three-way valve and the heat exchanger are closed, and other passages are opened, so that the engine coolant is self-circulated in the engine coolant circulation loop, and the engine coolant is heated by the heat generated by the engine. After reaching a set temperature, by controlling the on-off of each passage of the first three-way valve, the second three-way valve and the third three-way valve, the heated engine coolant flows to the heat exchanger under the action of the first water pump, and at the same time, the power battery coolant to be heat exchanged also flows to the heat exchanger under the action of the second water pump, and then the heated engine coolant and the power battery coolant to be heat exchanged perform heat exchange in the heat exchanger, and the engine coolant that completes the heat exchange returns to the engine coolant circulation loop to continue to be heated by the heat generated by the engine, and the heated power battery coolant is cooled by the heat exchanger. The power battery is heated by liquid, so as to utilize the waste heat of the engine to heat the power battery; when the power battery is heated by only the waste heat of the engine but the temperature of the power battery cannot meet the requirements, the PTC heater is controlled at this time, and the temperature-raised engine coolant is heated by the PTC heater. Since the temperature of the heated engine coolant is higher than that of the power battery coolant after heat exchange, the energy consumption of the PTC heater can be further reduced by heating the heated engine coolant by the PTC heater; finally, the power battery coolant that has been heated again is heat-exchanged with the power battery coolant to heat the power battery, so as to meet the requirements; the present invention utilizes the heat generated by the engine to heat the power battery, and while ensuring that the power battery pack is heated to a suitable operating temperature, the waste heat resources of the vehicle are fully and reasonably utilized, the energy utilization efficiency of the engine and the whole vehicle is improved, and the intervention of the water-heated PTC electric heater is reduced, thereby reducing a certain amount of energy consumption, increasing the driving range of the extended-range hybrid vehicle, and effectively improving the heating speed.

[0057] In one example, an engine coolant circulation loop includes:

[0058] Cylinder block water jacket, cylinder head water jacket, thermostat and third water pump;

[0059] The cylinder water jacket and the cylinder head water jacket are connected, the water inlet of the thermostat is connected to the water outlets of the cylinder water jacket and the cylinder head water jacket respectively, the water outlet of the thermostat is connected to the water inlet of the third water pump through the first three-way valve, and the water outlet of the third water pump is connected to the water inlet of the cylinder water jacket through the third three-way valve;

[0060] The cylinder body water jacket is provided with a plurality of first water inlets and first water outlets for communicating with the cylinder head water jacket, and the cylinder head water jacket is provided with a plurality of second water inlets and second water outlets corresponding to the first water inlets and the first water outlets; the first water inlet is communicated with the corresponding second water outlet, and the first water outlet is communicated with the second water inlet, so as to form a second flow chamber for heating the engine coolant.

[0061] Specifically, the engine coolant circulation loop is composed of a cylinder water jacket, a cylinder head water jacket, a thermostat and a third water pump. The cylinder water jacket and the cylinder head water jacket are connected. The cylinder water jacket is provided with a plurality of first water inlets and a first water outlet for communicating with the cylinder head water jacket. The cylinder head water jacket is provided with a plurality of second water inlets and a second water outlet corresponding to the first water inlets and the first water outlet. The first water inlet is connected to the corresponding second water outlet, and the first water outlet is connected to the second water inlet to form a second flow cavity for heating the engine coolant. The cylinder water jacket is provided with a plurality of first cavities corresponding to the first water inlet and the first water outlet, and the cylinder head water jacket is also provided with a plurality of second water inlets and a second water outlet corresponding to the second water inlet. The second cavity, the first cavity and the second cavity are connected through the first water inlet and the corresponding second water outlet, and the first water outlet and the corresponding second water inlet, forming a second flow cavity for heating the engine coolant; the water inlet of the thermostat is respectively connected to the water outlets of the cylinder water jacket and the cylinder head water jacket, the water outlet of the thermostat is connected to the water inlet of the third water pump through the first three-way valve, and the water outlet of the third water pump is connected to the water inlet of the cylinder water jacket through the third three-way valve; the thermostat automatically adjusts the amount of water entering the heat dissipation module according to the temperature of the engine coolant, changes the circulation range of the water, so as to adjust the heat dissipation capacity of the coolant and ensure that the engine works within a suitable temperature range. After the engine is started, the engine coolant circulation loop is closed by controlling the opening and closing of each channel of the first three-way valve and the third three-way valve, and the third water pump is controlled to start, so that the engine coolant circulates in the engine coolant circulation loop, and the second flow cavity formed by the cylinder water jacket and the cylinder head water jacket uses the heat generated by the engine to heat the engine coolant, so as to achieve full and reasonable use of the vehicle's waste heat resources.

[0062] In one example, it also includes:

[0063] The water outlet of the heat dissipation module and the PTC heater are connected to the water inlet of the heat dissipation module through the second three-way valve, and the water outlet of the heat dissipation module is connected to the water inlet of the engine coolant circulation loop.

[0064] Specifically, the power battery heating system of the present invention also includes a heat dissipation module, the water outlet of the PTC heater is connected to the water inlet of the heat dissipation module through a second three-way valve, and the water outlet of the heat dissipation module is connected to the water inlet of the engine coolant circulation loop; during the heating process, the heat dissipation module is isolated by controlling the on-off of each channel of the second three-way valve to prevent the heated engine coolant from entering the heat dissipation module; when the power battery is heated, in order to prevent the engine from overheating, the on-off of each channel of the second three-way valve is controlled to connect the engine coolant circulation loop with the heat dissipation module, at which time the engine coolant circulation loop remains disconnected from the heat exchanger, and the amount of engine coolant entering the heat dissipation module is automatically adjusted according to the temperature of the engine coolant through the thermostat, and the temperature of the engine coolant is lowered through the heat dissipation module, thereby reducing the temperature of the engine.

[0065] In one example, it also includes:

[0066] A first temperature acquisition module, used to acquire a first temperature of the engine coolant in the engine coolant circulation loop and send it to the controller;

[0067] The second temperature acquisition module is used to acquire the second temperature of the power battery and send it to the controller.

[0068] Specifically, the power battery heating system of the present invention also includes a first temperature acquisition module and a second temperature acquisition module. The first temperature acquisition module is used to acquire the first temperature of the engine coolant in the engine coolant circulation loop and send it to the controller, and the second temperature acquisition module is used to acquire the second temperature of the power battery and send it to the controller. For example, the first temperature acquisition module is an engine water temperature sensor installed on the engine, and the second temperature acquisition module is a power battery temperature sensor installed on the power battery.

[0069] In one example, the engine waste heat heating mode includes:

[0070] When the second temperature is lower than the first preset temperature threshold, the controller controls the ISG motor to start the engine with the set discharge power of the power battery, and controls the opening and closing of each channel of the first three-way valve and the third three-way valve to close the engine coolant circulation loop, and controls the third water pump to start, so that the engine coolant circulates in the engine coolant circulation loop, and heats the engine coolant in the second flow chamber using the heat generated by the engine;

[0071] When the first temperature is higher than the second preset temperature threshold, the controller controls the opening and closing of each channel of the first three-way valve, the second three-way valve and the third three-way valve to connect the engine coolant circulation loop with the heat exchanger, and controls the first water pump and the second water pump to start at the same time, so that the engine coolant exchanges heat with the power battery coolant in the heat exchanger, and heats the power battery in the first flow chamber using the power battery coolant that has completed the heat exchange;

[0072] When the second temperature reaches the third set temperature threshold, the controller controls the opening and closing of each channel of the second three-way valve to disconnect the engine coolant circulation loop from the heat exchanger and connect the engine coolant circulation loop to the heat dissipation module.

[0073] Specifically, the engine waste heat heating mode of the present invention is to heat the power battery only by using the engine waste heat. When the second temperature is lower than the first preset temperature threshold, the controller controls the ISG motor to start the engine with the set discharge power of the power battery. For example, the 5S discharge power of the power battery is used to control the ISG motor to start the engine, the battery stops discharging, and the engine is used to drive the ISG motor to generate electricity and then supply power to the whole vehicle; and the opening and closing of each channel of the first three-way valve and the third three-way valve are controlled to close the engine coolant circulation loop, and the third water pump is controlled to start at the same time, so that the engine coolant circulates in the engine coolant circulation loop, and the heat generated by the engine is used in the second flow chamber to continuously heat the engine coolant. When the temperature of the engine coolant, that is, the first temperature When the temperature of the power battery, i.e., the second temperature, reaches the third set temperature threshold, the controller controls the opening and closing of each channel of the second three-way valve to disconnect the engine coolant circulation loop from the heat exchanger, and connects the engine coolant circulation loop to the heat exchanger, and controls the first water pump and the second water pump to start at the same time, so that the engine coolant exchanges heat with the power battery coolant in the heat exchanger, and heats the power battery in the first flow chamber using the power battery coolant that has completed the heat exchange. When the temperature of the power battery, i.e., the second temperature, reaches the third set temperature threshold, the controller controls the opening and closing of each channel of the second three-way valve to disconnect the engine coolant circulation loop from the heat exchanger, and connects the engine coolant circulation loop to the heat dissipation module, and cools the engine coolant through the heat dissipation module, thereby cooling the engine to avoid engine overheating.

[0074] In one example, the combined heating mode includes:

[0075] When the power battery is heated by the engine waste heat heating mode for a set time and the second temperature is lower than the third set temperature threshold, the controller controls the PTC heater to heat the engine coolant flowing out of the engine coolant circulation loop until the second temperature reaches the third set temperature threshold, controls the opening and closing of each channel of the second three-way valve to disconnect the engine coolant circulation loop from the heat exchanger, connects the engine coolant circulation loop to the heat dissipation module, and controls the PTC heater to turn off.

[0076] Specifically, the combined heating mode of the present invention is: when the power battery is heated by the engine waste heat heating mode for a set time, and the temperature of the power battery, that is, the second temperature, is still lower than the third set temperature threshold, the controller controls the PTC heater to heat the engine coolant flowing out of the engine coolant circulation loop, and the controller performs table lookup calculation based on the power battery temperature collected by the second temperature collection module to obtain the target temperature requirement of the power battery for the hydrothermal heater PTC, and calculates the heater PTC power and the heater PTC gear according to the target temperature requirement of the heater PTC and the actual heater PTC outlet water temperature, so as to control the heater PTC to adjust to the corresponding gear to heat the engine coolant flowing out of the engine coolant circulation loop; until the second temperature reaches the third set temperature threshold, the opening and closing of each channel of the second three-way valve is controlled to disconnect the engine coolant circulation loop from the heat exchanger, connect the engine coolant circulation loop to the heat dissipation module, and control the PTC heater to be turned off. The present invention can reduce the intervention of the heater PTC, thereby reducing the energy consumption of the heater PTC and increasing the driving range of the extended-range hybrid vehicle. At the same time, the speed of heating the power battery using the engine waste heat is higher than the speed of heating the power battery using the heater PTC. The present invention can effectively increase the heating speed of the power battery.

[0077] In one example, after the ISG motor is started, the engine torque is calculated according to the power battery current of 0A. When the power battery current is less than a preset first current threshold, the controller controls the main positive relay and the main negative relay of the power battery to be disconnected;

[0078] When the second temperature reaches the third set temperature threshold, the controller controls the current generated by the ISG motor to be lower than the second current threshold, and then controls the main positive relay and the main negative relay of the power battery to close.

[0079] Specifically, after the ISG motor is started, the engine torque is calculated based on the power battery current of 0A. When the power battery current is less than the preset first current threshold, the controller controls the main positive relay and the main negative relay of the power battery to be disconnected to prevent a continuous small current from entering the power battery during the range extender startup heating and powering the vehicle's PTC and other accessories, causing battery crystallization. This can avoid the safety risks brought by battery crystallization accumulation. When the second temperature reaches the third set temperature threshold, the controller controls the current generated by the ISG motor to be lower than the second current threshold, and controls the main positive relay and the main negative relay of the power battery to be closed, so that the power battery can work normally and the vehicle can drive normally.

[0080] In one example, when the second temperature is lower than the third set temperature threshold, the controller controls the range extender to prohibit shutdown, controls the vehicle to prohibit shifting into the drive gear, and prompts the user on the dashboard that the power battery is being preheated.

[0081] Specifically, when the second temperature is lower than the third set temperature threshold, the main positive relay and the main negative relay of the power battery are disconnected, and the entire vehicle cannot be powered. The controller prohibits the range extender from shutting down and the vehicle from shifting into drive gear, that is, prohibits the vehicle from driving, and prompts the user on the dashboard that the power battery is preheating.

[0082] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments, but is not intended to be limiting of the present invention. It should be noted that the embodiments and features in the embodiments of the present invention may be combined with each other without conflict.

[0083] Embodiment 1

[0084] This embodiment provides a power battery heating system, including:

[0085] An engine small cycle loop, an engine large cycle loop, a range extender and a thermal management controller, the range extender includes an engine and an ISG motor; such as Figure 1 As shown, the engine large circulation loop includes a water pump 1, a water pump 2, a water thermal heater PTC, a three-way valve 1, a three-way valve 2, a three-way valve 3, a plate heat exchanger Chiller, a heater core and a power battery; the first channel of the three-way valve 1 is connected to the water inlet of the water pump 1 through a pipeline, the water outlet of the water pump 1 is connected to the water inlet of the water thermal heater PTC through a pipeline, the water outlet of the water thermal heater PTC is connected to the first channel of the three-way valve 3 through a pipeline, the second channel of the three-way valve 3 is connected to the first water inlet of the plate heat exchanger Chiller through a pipeline, the third channel of the three-way valve 3 is connected to the water inlet of the heater core through a pipeline, the plate heat exchanger Chiller The first water outlet of the chiller is respectively connected with the water outlet of the heater core and the first channel of the three-way valve 2 through a pipeline, the water outlet of the heater core is connected with the first channel of the three-way valve 2 through a pipeline, the first water outlet of the plate heat exchanger Chiller is connected with the first water inlet; the second water outlet of the plate heat exchanger Chiller is connected with the water inlet of the water pump 2 through a pipeline, the water outlet of the water pump 2 is connected with the water inlet of the cooling water channel in the power battery through a pipeline, the water outlet of the cooling water channel in the power battery is connected with the second water inlet of the plate heat exchanger Chiller through a pipeline, and the second water outlet and the second water inlet of the plate heat exchanger Chiller are connected;

[0086] like Figure 2As shown, the engine small circulation loop includes the engine's cylinder water jacket, cylinder head water jacket, three-way valve 1, three-way valve 2, thermostat and water pump 3, the second channel of the three-way valve 2 is connected to the water inlet of the cylinder water jacket through a pipeline, the third channel of the three-way valve 2 is connected to the water outlet of the water pump 3 through a pipeline, the water inlet of the water pump 3 is connected to the third channel of the three-way valve 1, the second channel of the three-way valve 1 is connected to the water outlet of the thermostat and the water outlet of the cylinder water jacket through a pipeline, the water outlet of the cylinder head water jacket is connected to the water inlet of the thermostat through a pipeline, a plurality of connected channels are provided between the cylinder water jacket and the cylinder head water jacket, the plurality of channels are connected end to end to form a flow cavity for heating the engine coolant, the engine coolant enters the flow cavity through the water inlet of the cylinder water jacket to be heated, and the heated engine coolant flows out through the water outlets of the cylinder water jacket and the cylinder head water jacket;

[0087] The power battery heating system of this embodiment further includes an engine water temperature sensor and a power battery temperature sensor. The engine water temperature sensor is installed at the water outlet of the thermostat, and the power battery temperature sensor is installed inside the power battery.

[0088] The power battery heating system of this embodiment includes an engine waste heat heating mode and a combined heating mode; the engine waste heat heating mode includes: the power battery temperature sensor collects the power battery temperature, and when the power battery temperature is lower than the preset temperature threshold T1 (-30°C, calibrable), the power battery issues a heating request; because the power battery temperature is too low, the range extender can only be started with the power battery's 5s discharge power, and the engine speed control is entered. The ISG calculates the torque based on the battery current of 0, and when the power battery current is less than the preset current threshold I1 (1A, calibrable), the power battery main positive relay and main negative relay are disconnected to prevent a continuous small current from entering the power battery during the range extender starting heating and supplying power to accessories such as the vehicle's PTC, thereby avoiding the safety risks caused by the accumulation of battery crystals. When the range extender engine is just started, its coolant temperature is low. At this time, the engine coolant is controlled to circulate in the engine's small circulation loop, that is, the second channel and the third channel of the three-way valve 2 and the three-way valve 1 are controlled to be opened, and the first channel of the three-way valve 2 and the three-way valve 1 are closed, and the water pump 3 is controlled to start. Under the action of the water pump 3, the engine coolant circulates in the engine's small circulation loop. During the circulation process, the engine coolant continuously exchanges heat with the engine cylinder block and the cylinder head, and the temperature continues to rise; the engine water temperature sensor collects the engine coolant temperature. When the coolant temperature is higher than the preset temperature threshold T2 (60°C, calibrable), it is considered that the heat of the engine coolant can be utilized. At this time, the first channel of the three-way valve 2 and the three-way valve 1 is controlled to be opened, and the third channel of the three-way valve 2 and the three-way valve 1 is closed. The three-way valve 2 and the three-way valve 1 remain open, the first channel and the second channel of the three-way valve 3 are opened, and the three-way valve 1 remains open. The third channel of the valve 3 is closed, the water pump 3 is controlled to stop, and the water pumps 1 and 2 are controlled to start. Under the action of the stone pump 1, the heated engine coolant is introduced into the plate heat exchanger Chiller through the three-way valve 1 and the three-way valve 2, and heat exchange is performed with the power battery coolant entering the plate heat exchanger Chiller under the action of the water pump 2. The engine coolant that has completed the heat exchange flows into the engine cylinder block water jacket and the cylinder head water jacket through the three-way valve 2 to continue to be heated; the power battery coolant that has completed the heat exchange flows into the power battery cooling water channel to exchange heat with the power battery and heat the power battery. After flowing out of the power battery cooling water channel, the power battery coolant continues to flow into the plate heat exchanger Chiller to exchange heat with the engine coolant; the power battery temperature sensor collects the power battery temperature again to detect whether the power battery temperature reaches the preset temperature threshold T3 (-25°C, calibrable). When the power battery temperature is lower than the preset temperature threshold T3, the range extender is prohibited from shutting down and the vehicle is prohibited from driving. At this time, the D and R gears cannot be engaged, and the instrument prompts the user that the battery is preheating; if the power battery temperature can reach the preset temperature threshold T3 within a certain time t1, it indicates that the heating demand of the power battery can be met by using only the heat provided by the engine coolant, and there is no need to turn on the water heater PTC.At the same time, the connection between the engine coolant circulation loop and the power battery coolant circulation loop can be disconnected, and the power battery can work normally.

[0089] If the power battery temperature has not reached the preset temperature threshold T3 within a certain period of time t1, it indicates that in this case, the power battery cannot be heated only by the heat provided by the engine coolant when the engine is running. At this time, the combined heating mode is adopted to control the water-heated heater PTC to turn on to assist in heating the power battery pack. Specifically, the thermal management system performs a table lookup calculation based on the power battery temperature collected by the temperature sensor to obtain the target temperature requirement of the power battery for the water-heated heater PTC, and then calculates the PTC power and PTC gear according to the PTC target temperature and the actual PTC outlet water temperature, so as to control the PTC to adjust to the corresponding gear; the power battery coolant and the engine coolant heated by the PTC and the engine exchange heat in the plate heat exchanger Chiller, and the heated power battery coolant heats the battery pack cells until the power battery is heated to the preset temperature threshold T3.

[0090] When it is detected that the power battery temperature reaches the preset temperature threshold T3, the third channel of the three-way valve 3 is controlled to open, the second channel is closed, and the first channel remains open, disconnecting the engine coolant circulation loop from the power battery coolant circulation loop, and turning off the water heater PTC at the same time; the engine coolant is controlled to enter the heater core, and the excess heat generated by the engine is dissipated through the heater core, and the current current of the ISG motor is controlled to be lower than a certain value I2, closing the power battery relay, so that the power battery can work normally and the vehicle can drive normally.

[0091] Embodiment 2

[0092] like Figure 3 As shown, this embodiment provides a power battery heating method, based on the power battery heating system described in Embodiment 1, comprising:

[0093] The power battery temperature is collected by the power battery temperature sensor to determine whether the power battery temperature is lower than a preset temperature threshold T1 (-30°C, calibrable). If so, the power battery issues a heating request.

[0094] Since the power battery temperature is too low, the range extender can only be started with the battery's 5s discharge power, and the engine speed control is entered. The ISG calculates the torque based on the battery current being 0. When the power battery current is less than the preset current threshold I1 (1A, calibrable), the main positive relay and main negative relay of the power battery are disconnected to prevent a continuous small current from entering the power battery during the process of the range extender starting to heat and supply power to accessories such as the vehicle's PTC, thereby avoiding the safety risks caused by the accumulation of battery crystals.

[0095] When the range extender engine is just started, its coolant temperature is relatively low. At this time, the range extender engine cooling system is controlled to perform a small cycle: the engine water pump drives the coolant to flow in the engine coolant circulation loop. After the engine coolant flows out of the water pump 3, it flows through the engine cylinder water jacket and the cylinder head water jacket, and finally flows back to the water pump 3. That is, the engine coolant circulates only between the engine cooling water jacket and the water pump. During the circulation process, the engine coolant continuously exchanges heat with the engine cylinder block and cylinder head, and the temperature continues to rise.

[0096] The engine water temperature sensor collects the engine coolant temperature and determines whether the coolant temperature is higher than the preset temperature threshold value T2 (60°C, calibrable). If so, it is considered that the heat of the engine coolant can be utilized, and the first channels of three-way valve 2 and three-way valve 1 are controlled to be opened, and the third channels of three-way valve 2 and three-way valve 1 are closed. Three-way valve 2 and three-way valve 1 remain open, the first channel and the second channel of three-way valve 3 are opened, and the third channel of three-way valve 3 is closed. Water pump 3 is controlled to stop, and water pump 1 and water pump 2 are controlled to start. Under the action of stone pump 1, the heated engine coolant is transferred through the three channels. The three-way valve 1 and the three-way valve 2 are introduced into the plate heat exchanger Chiller, and heat exchange is performed with the power battery coolant entering the plate heat exchanger Chiller under the action of the water pump 2. The engine coolant that has completed the heat exchange flows into the engine cylinder block water jacket and the cylinder head water jacket through the three-way valve 2 to continue to be heated; the power battery coolant that has completed the heat exchange flows into the power battery cooling water channel to perform heat exchange with the power battery to heat the power battery. After flowing out of the power battery cooling water channel, the power battery coolant continues to flow into the plate heat exchanger Chiller to exchange heat with the engine coolant.

[0097] The power battery temperature sensor collects the power battery temperature again and determines whether the power battery temperature can reach the preset temperature threshold T3 within a certain time t1. If so, the third channel of the three-way valve 3 is controlled to be opened, the second channel is closed, and the first channel remains open, disconnecting the engine coolant circulation loop from the power battery coolant circulation loop, and turning off the water heater PTC at the same time; controlling the engine coolant to enter the heater core, and the excess heat generated by the engine is dissipated through the heater core, and controlling the current current of the ISG motor to be lower than a certain value I2, closing the power battery relay, and the power battery can work normally and the vehicle can drive normally.

[0098] If the power battery temperature has not reached the preset temperature threshold T3 within a certain period of time t1, it indicates that in this case, the power battery cannot be heated only by the heat provided by the engine coolant when the engine is running. At this time, the combined heating mode is adopted to control the water-heated heater PTC to turn on to assist in heating the power battery pack. Specifically, the thermal management system performs a table lookup calculation based on the power battery temperature collected by the temperature sensor to obtain the target temperature requirement of the power battery for the water-heated heater PTC, and then calculates the PTC power and PTC gear according to the PTC target temperature and the actual PTC outlet water temperature, so as to control the PTC to adjust to the corresponding gear; the power battery coolant and the engine coolant heated by the PTC and the engine exchange heat in the plate heat exchanger Chiller, and the heated power battery coolant heats the battery pack cells until the power battery is heated to the preset temperature threshold T3.

[0099] Embodiment 3

[0100] This embodiment provides a vehicle, which includes the power battery heating system described in Embodiment 1.

[0101] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A power battery heating system, characterized in that: include: Range extender, including engine and ISG motor; A heat exchange circulation loop, comprising an engine coolant circulation loop, a first water pump, a PTC heater, a heat exchanger, a second water pump and a power battery; a water outlet of the engine coolant circulation loop is communicated with a water inlet of the first water pump through a first three-way valve, a water outlet of the first water pump is communicated with a water inlet of the PTC heater, a water outlet of the PTC heater is communicated with a hot water inlet of the heat exchanger through a second three-way valve, and a hot water outlet of the heat exchanger is communicated with a water inlet of the engine coolant circulation loop through a third three-way valve; A first flow chamber for circulating power battery coolant is provided inside the power battery, a water inlet of the first flow chamber is communicated with a water outlet of the second water pump, a water outlet of the flow chamber is connected with a cold water inlet of the heat exchanger, and a cold water outlet of the heat exchanger is connected with a water inlet of the second water pump; The controller is used to control the power battery heating system to heat the power battery in an engine waste heat heating mode or a combined heating mode.

2. The power battery heating system according to claim 1, characterized in that: The engine coolant circulation loop comprises: Cylinder block water jacket, cylinder head water jacket, thermostat and third water pump; The cylinder water jacket and the cylinder head water jacket are in communication, the water inlet of the thermostat is connected to the water outlets of the cylinder water jacket and the cylinder head water jacket respectively, the water outlet of the thermostat is connected to the water inlet of the third water pump through the first three-way valve, and the water outlet of the third water pump is connected to the water inlet of the cylinder water jacket through the third three-way valve; The cylinder body water jacket is provided with a plurality of first water inlets and a first water outlet for communicating with the cylinder head water jacket, and the cylinder head water jacket is provided with a plurality of second water inlets and a second water outlet corresponding to the first water inlets and the first water outlet; the first water inlet is communicated with the corresponding second water outlet, and the first water outlet is communicated with the second water inlet, so as to form a second flow chamber for heating the engine coolant.

3. The power battery heating system according to claim 2, characterized in that: Also includes: The heat dissipation module, the water outlet of the PTC heater is connected to the water inlet of the heat dissipation module through a second three-way valve, and the water outlet of the heat dissipation module is connected to the water inlet of the engine coolant circulation loop.

4. The power battery heating system according to claim 3, characterized in that: Also includes: A first temperature acquisition module, used for acquiring a first temperature of the engine coolant in the engine coolant circulation loop and sending it to the controller; The second temperature acquisition module is used to acquire the second temperature of the power battery and send it to the controller.

5. The power battery heating system according to claim 4, characterized in that: The engine waste heat heating mode includes: When the second temperature is lower than the first preset temperature threshold, the controller controls the ISG motor to start the engine with the set discharge power of the power battery, and controls the opening and closing of each channel of the first three-way valve and the third three-way valve to close the engine coolant circulation loop, and controls the third water pump to start, so that the engine coolant circulates in the engine coolant circulation loop, and heats the engine coolant in the second flow chamber by using the heat generated by the engine; When the first temperature is higher than the second preset temperature threshold, the controller controls the opening and closing of each channel of the first three-way valve, the second three-way valve and the third three-way valve to connect the engine coolant circulation loop with the heat exchanger, and controls the start of the first water pump and the second water pump at the same time, so that the engine coolant exchanges heat with the power battery coolant in the heat exchanger, and heats the power battery in the first flow chamber by using the power battery coolant that has completed the heat exchange; When the second temperature reaches a third set temperature threshold, the controller controls the opening and closing of each channel of the second three-way valve to disconnect the engine coolant circulation loop from the heat exchanger and connect the engine coolant circulation loop to the heat dissipation module.

6. The power battery heating system according to claim 5, characterized in that: The combined heating mode includes: When the power battery is heated by the engine waste heat heating mode for a set time and the second temperature is lower than a third set temperature threshold, the controller controls the PTC heater to heat the engine coolant flowing out of the engine coolant circulation loop until the second temperature reaches the third set temperature threshold, controls the opening and closing of each channel of the second three-way valve to disconnect the engine coolant circulation loop from the heat exchanger, connects the engine coolant circulation loop to the heat dissipation module, and controls the PTC heater to be turned off.

7. The power battery heating system according to claim 5, characterized in that: After the ISG motor is started, the engine torque is calculated according to the power battery current of 0A. When the power battery current is less than a preset first current threshold, the controller controls the main positive relay and the main negative relay of the power battery to be disconnected; When the second temperature reaches the third set temperature threshold, the controller controls the current generated by the ISG motor to be lower than the second current threshold, and then controls the main positive relay and the main negative relay of the power battery to close.

8. The power battery heating system according to claim 6, characterized in that: When the second temperature is lower than the third set temperature threshold, the controller controls the range extender to prohibit shutdown, controls the vehicle to prohibit shifting into a drive gear, and prompts the user on the instrument panel that the power battery is being preheated.

9. A power battery heating method, based on the power battery heating system according to any one of claims 1 to 8, characterized in that: include: collecting a first temperature of the engine coolant and a second temperature of the power battery; When the second temperature is lower than a first preset temperature threshold, the power battery issues a heating request; In response to the heating request, the ISG motor is started by the power battery and then the range extender is started, and the opening and closing of each channel of the first three-way valve and the third three-way valve are controlled to close the engine coolant circulation loop, and the engine coolant is heated by the heat generated by the engine; When the first temperature is higher than a second preset temperature threshold, the first three-way valve, the second three-way valve and the third three-way valve are controlled to be on and off so that the engine coolant circulation loop is connected to the heat exchanger, and the first water pump and the second water pump are controlled to start so that the engine coolant exchanges heat with the power battery coolant in the heat exchanger; If the second temperature reaches a third set temperature threshold within a set time, the on-off of each channel of the second three-way valve is controlled to disconnect the engine coolant circulation loop from the heat exchanger; If the second temperature is lower than the third set temperature threshold when the set time is reached, the PTC heater is controlled to heat the engine coolant flowing out of the engine coolant circulation loop until the second temperature reaches the third set temperature threshold, the opening and closing of each channel of the second three-way valve is controlled to disconnect the engine coolant circulation loop from the heat exchanger, and the PTC heater is controlled to be turned off.

10. A vehicle, characterized in that: The vehicle comprises the power battery heating system according to any one of claims 1-8.

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