Dual-power system for electric vehicle and its control method

Abstract

The present invention provides a dual-power supply system for an electric vehicle and a control method thereof. The dual-power supply system includes a first storage battery and a second storage battery, and the deep discharge capacity of the first storage battery is greater than that of the second storage battery. The control method includes: determining whether the ambient temperature of the first storage battery is less than a temperature threshold; if so, supplying power to the vehicle load by the second storage battery; if not, obtaining the vehicle power supply mode, and controlling the dual-power supply system to supply power to the vehicle load according to the state of charge of the first storage battery and the second storage battery and the vehicle power supply mode. The dual-power supply system and the control method provided by the present invention are applicable to a dual-power energy management scheme with different voltage levels, charge and discharge performances, and cycle service lives between storage batteries, improve the comprehensive service life of the dual-power supply system, and thus improve the user driving experience.

Description

Technical Field

[0001] The present invention belongs to the technical field of automotive battery system management, and particularly relates to a dual-power system for an electric vehicle and a control method thereof. Background Art

[0002] With the continuous development of the automotive "electrification, intelligent networking, sharing, and internationalization", automotive autonomous driving technology has become the focus of the automotive industry. Currently, the autonomous driving technology is in the transition period from L2 to L3. In the development and design of the power supply system, the biggest difference between the L3 autonomous driving system and the L2 autonomous driving system is that the power supply system is required to have redundant power supply nodes to ensure that the vehicle can keep the key functional modules running normally for more than 60 seconds in case of internal failures without the driver intervening in the vehicle control. Therefore, new energy vehicles at the L3 autonomous driving level need to be equipped with at least a dual-power system during the development process.

[0003] From the perspectives of layout space and reducing the risk of power shortage, for the dual-power system adopted by new energy vehicles at the L3 autonomous driving level, generally, there are differences in the voltage levels, charge and discharge performance, and cycle service life of the two power supplies. For example, a dual-power system composed of a lead-acid battery and a lithium iron phosphate battery is one of the preferred solutions. However, if the existing energy management strategy is adopted for this system, that is, the battery with a higher power level is preferably used as the main power supply, and the other battery is used as the auxiliary power supply, it is easy to cause uneven service life of the two power supplies. Summary of the Invention

[0004] The purpose of the present invention is to solve the problem that the existing control method for the dual-power system at the L3 autonomous driving level is easy to cause uneven service life of the two power supplies. A dual-power system for an electric vehicle and a control method thereof are provided, which are applicable to the dual-power energy management scheme with different voltage levels, charge and discharge performance, and cycle service life between the batteries, improving the comprehensive service life of the dual-power system, thereby improving the user driving experience.

[0005] To solve the above technical problems, the present invention provides a control method for a dual-power system of an electric vehicle. The dual-power system includes a first battery and a second battery, and the deep discharge capacity of the first battery is greater than that of the second battery. The control method includes the following steps.

[0006] Obtain battery information, where the battery information includes the ambient temperature of the first battery and the state of charge of the first battery and the second battery.

[0007] Determine whether the ambient temperature of the first battery is less than the temperature threshold; if so, determine that the dual-power system is in a low-temperature working condition, and the second battery supplies power to the vehicle load; if not, determine that the dual-power system is in a normal-temperature working condition, obtain the vehicle power mode, and control the dual-power system to supply power to the vehicle load according to the state of charge of the first battery and the second battery and the vehicle power mode.

[0008] Among them, when the vehicle power mode is the driving mode, the DC-DC converter supplies power to the load; and the DC-DC converter charges the first battery and the second battery.

[0009] When the vehicle power mode is the parking mode, the sleep mode, or the start mode, among them, when the state of charge of the first battery is greater than the first redundancy threshold, at least the first battery supplies power to the vehicle load; when the state of charge of the first battery is less than or equal to the first redundancy threshold and the state of charge of the second battery is greater than the second discharge deficit threshold, the second battery supplies power to the vehicle load; when the state of charge of the first battery is less than or equal to the first redundancy threshold and greater than the first discharge deficit threshold, and the state of charge of the second battery is less than or equal to the second discharge deficit threshold, the first battery supplies power to the vehicle load; when the state of charge of the first battery is less than or equal to the first discharge deficit threshold and the state of charge of the second battery is less than or equal to the second discharge deficit threshold, the first battery supplies power to the vehicle load; among them, the first redundancy threshold is greater than the first discharge deficit threshold, and the first discharge deficit threshold is less than the second discharge deficit threshold.

[0010] Adopting the above solution, the dual-power system and control method provided by the present invention can effectively avoid the problem of mutual discharge between the two power sources. The control method of the dual-power system sets a set temperature threshold according to the different discharge characteristics of the two batteries, formulates a battery low-temperature energy management strategy, takes into account the poor low-temperature performance of the first battery, ensures the driving ability of the vehicle to operate normally in a low-temperature environment, and improves driving safety.

[0011] Furthermore, a first redundancy threshold and a first discharge deficit threshold are set for the first battery with strong deep discharge ability; a second discharge deficit threshold is set according to the discharge characteristics of the second battery with weak deep discharge ability. Setting the first state-of-charge redundancy threshold can protect the first battery. When the state of charge of the first battery drops to the first redundancy threshold, the first battery can still provide a certain number of starting energies. When the power of the first battery drops to the first discharge deficit threshold and below, its deep discharge ability can still supply power to the load for a short time to ensure driving safety; at the same time, the energy distribution methods for scenarios such as sleep, parking, start, and driving are designed. Utilizing the fast charging ability and deep discharge ability of the first battery to achieve the protection of the second battery, thereby protecting the dual-power system, which is beneficial to slowing down the aging speed of the battery and improving the comprehensive service life of the dual-power system and the user driving experience.

[0012] According to another specific embodiment of the present invention, for the control method disclosed in the embodiment of the present invention, the vehicle load includes an entertainment load with entertainment functions and a safety load with safety functions.

[0013] In the parking mode, when the state of charge of the first battery is greater than the first full threshold, the first battery supplies power to the vehicle load; when the state of charge of the first battery is greater than the first redundancy threshold and less than the first full threshold, and the state of charge of the second battery is greater than the second discharge threshold, the first battery supplies power to the safety load, and the second battery supplies power to the entertainment load; when the state of charge of the first battery is greater than the first redundancy threshold and less than the first full threshold, and the state of charge of the second battery is less than or equal to the second discharge threshold, the first battery supplies power to the vehicle load; when the state of charge of the first battery is less than or equal to the first discharge threshold, and the state of charge of the second battery is less than or equal to the second discharge threshold, the first battery supplies power to the safety load, and the entertainment load is disconnected.

[0014] In the sleep mode or the start mode, when the state of charge of the first battery is greater than the first redundancy threshold, the first battery supplies power to the vehicle load; when the state of charge of the first battery is less than or equal to the first discharge threshold, and the state of charge of the second battery is less than or equal to the second discharge threshold, the first battery supplies power to the safety load, and the entertainment load is disconnected; wherein, the first full threshold is greater than the first redundancy threshold.

[0015] By adopting the above solution, the vehicle electrical appliance loads are divided into two parts: an entertainment load and a safety load. The power supply methods for the two types of loads are determined according to the vehicle power supply mode and the battery power conditions of the dual batteries. Priority is given to ensuring power supply to the safety load. On the premise of ensuring driving safety, the energy output of the dual power sources is reasonably allocated to improve the driving experience.

[0016] According to another specific embodiment of the present invention, for the control method disclosed in the embodiment of the present invention, the battery information further includes the battery health of the first battery and the second battery; the control method further includes, before judging whether the ambient temperature is less than the temperature threshold, judging whether the first battery and the second battery are in a failure state according to the battery information; if it is judged that the first battery is in a failure state, the power supply circuit of the first battery is disconnected; if it is judged that the second battery is in a failure state, the power supply circuit of the second battery is disconnected.

[0017] By adopting the above solution, a redundant power supply system is designed. When one battery fails in the dual power supply system, the other battery can perform redundant power supply to ensure driving safety.

[0018] According to another specific embodiment of the present invention, the control method disclosed in the embodiment of the present invention further includes: in a low-temperature working condition, when the state of charge of the second battery is less than or equal to the second full threshold and greater than the second discharge threshold, a prompt message is sent through the prompt device to prompt to start the vehicle as soon as possible; when the state of charge of the second battery is less than or equal to the second discharge threshold, a prompt message is sent through the prompt device to prompt to implement pump power rescue as soon as possible.

[0019] In a normal-temperature working condition, when the state of charge of the first battery is less than or equal to the first redundancy threshold and greater than the first discharge threshold, and the state of charge of the second battery is less than or equal to the second discharge threshold, a prompt message is sent through the prompt device to prompt to start the vehicle as soon as possible; when the state of charge of the first battery is less than or equal to the first discharge threshold, and the state of charge of the second battery is less than or equal to the second discharge threshold, a prompt message is sent through the prompt device to prompt to implement pump power rescue as soon as possible.

[0020] Wherein, the second full threshold is greater than the second discharge threshold.

[0021] Adopting the above scheme, a reasonable human-computer interaction scheme is proposed for the low battery power scenario of the battery, reminding the user to start the vehicle in time and reducing the risk of battery discharge.

[0022] According to another specific embodiment of the present invention, the control method disclosed in the embodiment of the present invention, the prompt device includes a mobile terminal and an instrument panel; wherein, in the sleep mode, a prompt message is sent through the mobile terminal; in the parking mode or the start mode, a prompt message is sent through the instrument panel.

[0023] According to another specific embodiment of the present invention, the control method disclosed in the embodiment of the present invention further includes: in the start mode, the start control module connected in parallel with the safety load turns on the start circuit, so that the first battery or the second battery supplies power to the start circuit.

[0024] According to another specific embodiment of the present invention, the control method disclosed in the embodiment of the present invention, the first battery is a lithium iron phosphate battery, and the second battery is a lead-acid battery.

[0025] The present invention also provides a dual-power system for an electric vehicle, which is used to execute the control method of the dual-power system for an electric vehicle provided by the present invention; the dual-power system includes a control module, a first battery, a second battery, a battery information acquisition module, and a DC-DC converter.

[0026] The control module, the control module obtains the vehicle power supply mode and is connected to the vehicle load through the load node.

[0027] A first battery and a second battery, wherein the deep discharge capacity of the first battery is greater than that of the second battery; and the first battery is connected to the control module through a first node, and the second battery is connected to the control module through a second node.

[0028] A battery information acquisition module, which is connected to the first battery and the second battery and is used to obtain battery information. The battery information includes the ambient temperature of the first battery, and the state of charge of the first battery and the second battery; the battery information acquisition module is also communicatively connected to the control module to transmit the battery information to the control module.

[0029] A DC-DC converter, which is connected to the control module through a third node.

[0030] Wherein, the control module controls the conduction state of the dual-power supply system according to the vehicle power supply mode and the battery information to control the dual-power supply system to supply power to the vehicle load; when the control module makes the first node conduct with the load node and both the second node and the third node are disconnected, the first battery supplies power to the vehicle load; when the control module makes the second node conduct with the load node and both the first node and the third node are disconnected, the second battery supplies power to the vehicle load; when the control module makes the first node, the second node, the third node and the load node conduct, the DC-DC converter supplies power to the vehicle load, and the DC-DC converter charges the first battery and the second battery.

[0031] According to another specific embodiment of the present invention, for the dual-power supply system disclosed in the embodiment of the present invention, the vehicle load includes an entertainment load with entertainment functions and a safety load with safety functions, and the load node includes a fourth node and a fifth node; the entertainment load is connected to the control module through the fourth node, and the safety load is connected to the control module through the fifth node.

[0032] When the control module makes the first node conduct with the fifth node, the second node conduct with the fourth node, and the third node is disconnected, the first battery supplies power to the safety load, and the second battery supplies power to the entertainment load; when the control module makes the first node conduct with the fifth node, and both the second node, the fourth node and the third node are disconnected, the first battery supplies power to the safety load, and the entertainment load is disconnected.

[0033] According to another specific embodiment of the present invention, for the dual-power supply system disclosed in the embodiment of the present invention, the battery information further includes the battery health of the first battery and the second battery; the battery information acquisition module includes a battery management system and a battery current sensor; the battery management system is connected to the first battery and is used to obtain the ambient temperature, state of charge and battery health of the first battery; the battery current sensor is connected to the second battery and is used to obtain the state of charge and battery health of the second battery.

[0034] The dual-power supply system further includes a first electrical center and a second electrical center. The first electrical center is connected to the first storage battery, and the second electrical center is connected to the second storage battery. When the first electrical center is controlled to be disconnected, the power supply circuit of the first storage battery is disconnected. When the second electrical center is controlled to be disconnected, the power supply circuit of the second storage battery is disconnected.

[0035] According to another specific embodiment of the present invention, the dual-power supply system disclosed in the embodiment of the present invention is further connected to a prompting device and a starting control module. Among them, the prompting device is connected to the control device and is used to receive and display the prompting information transmitted by the control device. The prompting device includes a mobile terminal and a dashboard. The starting control module is connected in parallel with the safety load and is used to connect the starting circuit when the vehicle power supply mode is in the starting mode.

[0036] The beneficial effects of the present invention are:

[0037] The dual-power supply system and control method provided by the present invention can effectively avoid the problem of mutual discharge between the dual power supplies, and formulate a battery low-temperature energy management strategy for the different voltage levels, charge and discharge performance, and cycle service life of the two storage batteries, ensuring the driving ability of the vehicle to operate normally in a low-temperature environment and improving driving safety. Further, a first redundancy threshold and a first power shortage threshold are set for the first storage battery with strong deep discharge ability; a second power shortage threshold is set for the discharge characteristics of the lithium iron phosphate storage battery with weak deep discharge ability, and at the same time, the energy distribution methods for scenarios such as dormancy, parking, starting, and driving are designed. By using the fast charging ability and deep discharge ability of the first storage battery, the protection of the second storage battery and the dual-power supply system is realized, which is beneficial to slowing down the aging speed of the storage battery, improving the comprehensive service life of the dual-power supply system and the user driving experience. Description of the Drawings

[0038] Figure 1 It is a circuit structure schematic diagram of the dual-power supply system of the electric vehicle and the vehicle load of the present invention;

[0039] Figure 2 It is a flowchart of the control method of the dual-power supply system of the electric vehicle in Embodiment 1 of the present invention;

[0040] Figure 3 It is a flowchart of the control method of the dual-power supply system of the electric vehicle in Embodiment 3 of the present invention.

[0041] Description of the Reference Numerals:

[0042] 100: Control module;

[0043] 110: First node; 120: Second node; 130: Third node; 140: Load node; 141: Fourth node; 142: Fifth node;

[0044] 200: First storage battery;

[0045] 300: Second storage battery;

[0046] 400: Battery information acquisition module;

[0047] 410: Battery management system; 420: Battery current sensor;

[0048] 500: DC - DC converter;

[0049] 600: Vehicle load;

[0050] 610: Entertainment load; 620: Safety load;

[0051] 700: Starting control module;

[0052] 800: First electrical center;

[0053] 900: Second electrical center. Detailed implementation mode

[0054] The following specific embodiments illustrate the implementation modes of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Although the description of the present invention will be introduced in conjunction with preferred embodiments, this does not mean that the features of this invention are limited to this implementation mode. On the contrary, the purpose of introducing the invention in conjunction with the implementation mode is to cover other alternatives or modifications that may be extended based on the claims of the present invention. In order to provide a deep understanding of the present invention, many specific details will be included in the following description. The present invention can also be implemented without using these details. In addition, in order to avoid confusion or obscuring the key points of the present invention, some specific details will be omitted in the description. It should be noted that, without conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0055] It should be noted that in this specification, similar reference numerals and letters indicate similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0056] The terms "first", "second", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0057] In the description of this embodiment, it should also be noted that, unless otherwise clearly specified and limited, the terms "set", "connected", and "connected" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in this embodiment can be understood according to specific situations.

[0058] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0059] Embodiment 1

[0060] The present invention provides a dual-power system for an electric vehicle, as Figure 1 shown, which includes a control module 100, a first battery 200, a second battery 300, a battery information acquisition module 400, and a DC-DC converter (HVDCDC) 500.

[0061] The control module 100 is used to control the power supply of the dual-power system as a whole. The control module 100 is also connected to other relevant control or acquisition modules of the vehicle through an automotive bus such as a CAN bus to obtain vehicle-related information. Specifically, it can obtain the vehicle power supply mode; and the control module 100 has multiple circuit connection nodes, and different circuits can be controlled to be connected by turning on or off different nodes. Among them, the control module 100 is connected to the vehicle load 600 through the load node 140.

[0062] In the system, the specific types of the first battery 200 and the second battery 300 can be selected according to the vehicle needs. However, the deep discharge capacity of the first battery 200 is greater than that of the second battery 300. In one specific embodiment of the present invention, the first battery 200 is a lithium iron phosphate battery (Bat Li ), and the second battery 300 is a lead-acid battery (Bat pb ). And the first battery 200 is connected to the control module 100 through the first node 110, and the second battery 300 is connected to the control module 100 through the second node 120.

[0063] The battery information acquisition module 400 is connected to the first storage battery 200 and the second storage battery 300, and is used to acquire battery information. The battery information includes the ambient temperature of the first storage battery 200, and the state of charge (SOC) of the first storage battery 200 and the second storage battery 300. Specifically, the battery information acquisition module 400 can be a device such as a sensor for acquiring battery-related information. It can be one, connected to the first storage battery 200 and the second storage battery 300 simultaneously to acquire battery information; or it can be two, respectively connected to the first storage battery 200 and the second storage battery 300 to acquire the information of the two storage batteries respectively.

[0064] In a specific embodiment of the present invention, the battery information acquisition module 400 includes a battery management system (BMS) 410 and a battery current sensor (EBS) 420; the battery management system 410 is connected to the first storage battery 200 to detect performance parameters such as the voltage, current, and ambient temperature of the first storage battery 200, and obtain the state of charge of the first storage battery 200 according to these parameters. The battery current sensor 420 is connected to the second storage battery 300 to detect performance parameters such as the voltage, current, and ambient temperature of the second storage battery 300, and obtain the state of charge of the second storage battery 300 according to these parameters.

[0065] The battery information acquisition module 400 is also communicatively connected to the control module 100. Specifically, it can be communicatively connected to the control module 100 through an automotive bus, and transmit the acquired battery information including the ambient temperature and state of charge of the first storage battery 200, and the state of charge of the second storage battery 300 to the control module 100 through a LIN bus or the like. For the embodiment in which the battery management system (BMS) 410 and the battery current sensor (EBS) 420 are respectively provided, the battery current sensor 420 and the battery management system 410 are respectively communicatively connected to the control module 100 to transmit data.

[0066] The DC-DC converter 500 is connected to the control module 100 through the third node 130. The DC-DC converter 500 is used to convert the high-voltage direct current of the power battery into low-voltage direct current to charge the dual storage batteries during vehicle driving.

[0067] Among them, the control module 100 controls the conduction states of different circuit connection nodes including the first node 110, the second node 120, the third node 130, and the load node 140 according to the vehicle power supply mode and battery information, so as to control the power supply of the dual power supply system to the vehicle load 600, and realize reasonable energy output distribution on the basis of avoiding mutual charging and discharging between the first storage battery 200 and the second storage battery 300.

[0068] Among them, when the conduction between the first node 110 and the load node 140 is controlled and both the second node 120 and the third node 130 are disconnected, the first storage battery 200 supplies power to the vehicle load 600; when the conduction between the second node 120 and the load node 140 is controlled and both the first node 110 and the third node 130 are disconnected, the second storage battery 300 supplies power to the vehicle load 600; when the conduction among the first node 110, the second node 120, the third node 130 and the load node 140 is controlled, the DC-DC converter 500 supplies power to the vehicle load 600, and the DC-DC converter 500 charges the first storage battery 200 and the second storage battery 300.

[0069] Furthermore, the present invention also provides a control method for the above-mentioned dual-power supply system of an electric vehicle. The control method is mainly executed by a control module, as Figure 2 shown. The control method includes the following steps:

[0070] The battery information acquisition module acquires the storage battery information. The storage battery information includes the ambient temperature of the first storage battery and the state of charge of the first storage battery and the second storage battery. The battery information acquisition module transmits the storage battery information to the control module.

[0071] After the control module acquires the storage battery information, it judges whether the ambient temperature of the first storage battery is less than the temperature threshold; if so, it judges that the dual-power supply system is in a low-temperature working condition. When the control module controls both the second node and the load node to be conductive and both the first node and the third node to be disconnected, the second storage battery supplies power to the vehicle load; if not, it judges that the dual-power supply system is in a normal-temperature working condition. The control module acquires the vehicle power supply mode and controls the dual-power supply system to supply power to the vehicle load according to the state of charge of the first storage battery and the second storage battery and the vehicle power supply mode.

[0072] Among them, the vehicle power supply mode includes a sleep mode (OFF gear), a parking mode (ACC gear), a starting mode (CRANK gear) and a driving mode (RUN gear); when the vehicle power supply mode is the driving mode, the first node, the second node, the third node and the load node are conducted with each other, and the DC-DC converter supplies power to the vehicle load, and the DC-DC converter charges the first storage battery and the second storage battery.

[0073] Further, considering the charging efficiency, a first charging termination threshold and a second charging termination threshold can be respectively set for the first storage battery and the second storage battery. When the charge of the first storage battery reaches the first charging termination threshold, the second node is controlled to disconnect, and the HVDCDC supplies power to the vehicle load and only charges the second storage battery; when the charge of the second storage battery reaches the second charging termination threshold, the first node is controlled to disconnect, and the HVDCDC only supplies power to the vehicle load. It should be noted that the first charging termination threshold and the second charging termination threshold are respectively calibrated according to the charging characteristics of the first dual storage battery and the second storage battery and the ambient temperature.

[0074] When the vehicle power supply mode is the parking mode, the sleep mode or the start mode, the first storage battery preferentially supplies power to the vehicle load. Among them, when the state of charge of the first storage battery is greater than the first redundancy threshold, at least the first storage battery supplies power to the vehicle load; it should be noted that in the present invention, at least the first storage battery supplies power to the vehicle load, which means that according to the demand, the vehicle load can be completely supplied with power by the first storage battery, that is, the first node is controlled to conduct with the load node, and the second node and the third node are both disconnected; or on the basis that the charge (state of charge) of the second storage battery is sufficient, the first storage battery can also supply power to some vehicle loads, and the second storage battery supplies power to other vehicle loads, that is, the first node is controlled to conduct with some vehicle loads, the second node is controlled to conduct with other vehicle loads, and the third node is disconnected.

[0075] When the state of charge of the first storage battery is less than or equal to the first redundancy threshold and the state of charge of the second storage battery is greater than the second discharge deficit threshold, the second node is controlled to conduct with the load node, and the first node and the third node are both disconnected, and the second storage battery supplies power to the vehicle load.

[0076] When the state of charge of the first storage battery is less than or equal to the first redundancy threshold and greater than the first discharge deficit threshold, and the state of charge of the second storage battery is less than or equal to the second discharge deficit threshold, the first node is controlled to conduct with the load node, and the second node and the third node are both disconnected, and the first storage battery supplies power to the vehicle load.

[0077] When the state of charge of the first storage battery is less than or equal to the first discharge deficit threshold and the state of charge of the second storage battery is less than or equal to the second discharge deficit threshold, the first storage battery supplies power to the vehicle load. However, at this time, the charges of both the first storage battery and the second storage battery are relatively low, and the power supply time for the vehicle load is short, and it may only be used to complete safety operations such as steering and braking.

[0078] Among them, the first redundancy threshold is greater than the first discharge deficit threshold, and since the first storage battery has a stronger deep discharge capacity than the second storage battery, the first discharge deficit threshold is less than the second discharge deficit threshold.

[0079] It should be noted that the temperature threshold is calibrated according to the influence of temperature on battery performance. For example, specifically, according to the relationship curve between temperature and battery performance, when at a certain temperature, the curve shows that the battery performance significantly decreases, then this temperature is taken as the temperature threshold. Different battery types have different temperature thresholds. Taking the first storage battery as a lithium iron phosphate storage battery as an example, the temperature threshold can be -5, -10°C, -15°C, etc.

[0080] The first redundancy threshold, the first undercharge threshold, and the second undercharge threshold are obtained through calibration and determined according to the relationship between the battery charge and battery performance. Different battery types obtain different specific thresholds. In the present invention, two thresholds are set for the first storage battery with strong deep discharge ability: the first redundancy threshold indicates that above the first storage battery protection charge value, discharging above this charge (i.e., state of charge) does not affect the battery performance. Taking the first storage battery as a lithium iron phosphate storage battery as an example, the first redundancy threshold can be set to a certain value between 30% and 50%, specifically 40%; the first undercharge threshold indicates that when the first storage battery discharges below this charge, it will affect the battery performance and may cause battery damage. Taking the first storage battery as a lithium iron phosphate storage battery as an example, the first undercharge threshold can be set to 10%. The present invention sets one threshold, the second undercharge threshold, for the second storage battery with weak deep discharge ability. Since the second storage battery has weak discharge ability when the charge is low, the second undercharge threshold is greater than the first undercharge threshold. Taking the second storage battery as a lead-acid storage battery as an example, the second undercharge threshold can be set to a certain value between 30% and 40%.

[0081] Adopting the above solution, the dual-power system and control method provided by the present invention can effectively avoid the problem of mutual discharge between the dual power supplies, and set temperature thresholds and formulate a battery low-temperature energy management strategy according to the different voltage levels, charge and discharge performance, and cycle service life of the two storage batteries. Considering that the first storage battery has poor low-temperature performance, it ensures the driving ability of the vehicle to operate normally in a low-temperature environment and improves driving safety.

[0082] Furthermore, a first redundancy threshold and a first undercharge threshold are set for the first storage battery with strong deep discharge ability; a second undercharge threshold is set according to the discharge characteristics of the lithium iron phosphate storage battery with weak deep discharge ability. Setting the first charge redundancy threshold can protect the first storage battery. When the state of charge of the first storage battery drops to the first redundancy threshold, the first storage battery can still provide a certain number of starting energies. When the charge of the first storage battery drops to the undercharge threshold, it can still provide short-term power supply for the load using its deep discharge ability to ensure driving safety; at the same time, the energy distribution methods for scenarios such as dormancy, parking, starting, and driving are designed, and the fast charging ability and deep discharge ability of the first storage battery are utilized to protect the second storage battery, thereby protecting the dual-power system, which is beneficial to slowing down the aging speed of the storage battery and improving the comprehensive service life of the dual-power system and the user driving experience.

[0083] Embodiment 2

[0084] Based on Embodiment 1, as Figure 1 shown, in the dual-power supply system, the vehicle load 600 includes an entertainment load 610 with entertainment functions or comfort functions and a safety load 620 with safety functions. The entertainment load 610 specifically includes an air conditioner, lights, an entertainment screen, etc. The safety load 620 specifically includes a body controller, an electric power steering system (EPS), an electronic stability program system (ESP), and autonomous driving safety components including an advanced driver assistance system (ADAS), a radar, a camera, etc. The load node 140 includes a fourth node 141 and a fifth node 142; the entertainment load 610 is connected to the control module 100 through the fourth node 141, and the safety load 620 is connected to the control module 100 through the fifth node 142.

[0085] Among them, when the first node 110 and the fifth node 142 are controlled to conduct with each other, the second node 120 and the fourth node 141 conduct with each other, and the third node 130 is disconnected, the first battery 200 supplies power to the safety load 620, and the second battery 300 supplies power to the entertainment load 610; when the first node 110 and the fifth node 142 are controlled to conduct with each other, and the second node 120, the third node 130, and the fourth node 141 are all disconnected, the first battery 200 supplies power to the safety load 620, and the entertainment load 610 is disconnected. Specifically, the control module 100 controls the conduction states of different circuit connection nodes in the dual-power supply system (the circuit connection methods in Table 1) to control the power supply of the dual-power supply system to the vehicle load 600. The control modes of the dual-power supply system for supplying power to the vehicle load 600 are shown in Table 1.

[0086] Table 1 Control Modes of the Control Module

[0087]

[0088] In the above table, 1, 2, 3, 4, and 5 represent the first node 110, the second node 120, the third node 130, the fourth node 141, and the fifth node 142 in sequence.

[0089] Further, the control method of the dual-power supply system further includes: in the parking mode, when the state of charge of the first battery is greater than the first full threshold, it indicates that the state of charge of the first battery is in the high battery charge range, and the control mode of the control module is Mode 1, and the first battery supplies power to the vehicle load; when the state of charge of the first battery is greater than the first redundancy threshold and less than or equal to the first full threshold, it indicates that the state of charge of the first battery is in the medium battery charge range, and when the state of charge of the second battery is greater than the second discharge threshold, the control mode of the control module is Mode 3, the first battery supplies power to the safety load, and the second battery supplies power to the entertainment load; when the state of charge of the first battery is greater than the first redundancy threshold and less than or equal to the first full threshold, and the state of charge of the second battery is less than or equal to the second discharge threshold, the control mode of the control module is Mode 1, and the first battery supplies power to the vehicle load; when the state of charge of the first battery is less than or equal to the first redundancy threshold, and the state of charge of the second battery is greater than the second full threshold, the control mode of the control module is Mode 2, and the second battery supplies power to the vehicle load; when the state of charge of the first battery is less than or equal to the first redundancy threshold, and the state of charge of the second battery is less than or equal to the second full threshold and greater than the second redundancy threshold, the control mode of the control module is Mode 2, the first battery supplies power to the vehicle load, and the high-power entertainment load function is restricted; when the state of charge of the first battery is less than or equal to the first redundancy threshold and greater than the first discharge threshold, and the state of charge of the second battery is less than or equal to the second discharge threshold, the control mode of the control module is Mode 1, the first battery supplies power to the vehicle load, and the high-power entertainment load function is turned off; when the state of charge of the first battery is less than or equal to the first discharge threshold, and the state of charge of the second battery is less than or equal to the second discharge threshold, the control mode of the control module is Mode 5, the first battery supplies power to the safety load, and the entertainment load is disconnected.

[0090] In the sleep mode or the start mode, when the state of charge of the first battery is greater than the first redundancy threshold, the control mode of the control module is Mode 1, and the first battery supplies power to the vehicle load; when the state of charge of the first battery is less than or equal to the first discharge threshold, and the state of charge of the second battery is less than or equal to the second discharge threshold, the control mode of the control module is Mode 5, the first battery supplies power to the safety load, and the entertainment load is disconnected. When the state of charge of the first battery and the state of charge of the second battery are in other ranges, the control method is the same as that in Embodiment 1.

[0091] Among them, the first full threshold is greater than the first redundancy threshold; the second full threshold is greater than the second redundancy threshold.

[0092] It should be noted that the sufficient threshold represents that the battery power is relatively sufficient, which is the threshold in the high power region and is obtained through calibration and determined according to the relationship between the power and the battery performance. The specific thresholds obtained for different battery types are different. Taking the first battery as a lithium iron phosphate battery as an example, the first sufficient threshold can be set to a certain value within 60-70%; taking the second battery as a lead-acid battery as an example, the second sufficient threshold can be set to a certain value within 60-70%.

[0093] In a specific embodiment of the present invention, as Figure 1 shown, the dual power supply system is also connected to the start control module 700. The start control module 700 is connected in parallel with the safety load 620 and is used to turn on the start circuit when the vehicle power supply mode is in the start mode. The control method further includes that when in the start mode, the start control module connected in parallel with the safety load turns on the start circuit so that the first battery or the second battery supplies power to the start circuit.

[0094] By adopting the above solution, the present invention divides the vehicle electrical appliance loads into two parts: entertainment loads and safety loads. The power supply methods of the two types of loads are determined according to the vehicle power supply mode and the battery power conditions of the dual batteries. Priority is given to ensuring power supply to the safety loads. On the premise of ensuring driving safety, the energy output of the dual power supplies is reasonably distributed to improve the driving experience.

[0095] Embodiment 3

[0096] Based on the above Embodiment 1 or 2, the battery information further includes the state of health (SOH) of the first battery 200 and the second battery 300; in the dual power supply system, as Figure 1 shown, the battery information acquisition module 400 includes a battery management system 410 and a battery current sensor 420; the battery management system 410 is connected to the first battery 200 to detect performance parameters such as the voltage, current, and ambient temperature of the first battery 200, and obtain the state of charge (SOC) and the state of health (SOH) of the first battery 200 according to these parameters. The battery current sensor 420 is connected to the second battery 300 to detect performance parameters such as the voltage, current, and ambient temperature of the second battery 300, and obtain the state of charge and the state of health of the second battery 300 according to these parameters.

[0097] As Figure 1As shown, the dual-power supply system further includes a first electrical center (EC1) 800 and a second electrical center (EC2) 900. The first electrical center 800 is connected to the first battery 200, and the second electrical center 900 is connected to the second battery 300. The function of the electrical center is that when a certain battery fails due to aging, collision or other reasons, the fuse in the electrical center corresponding to that battery will blow to protect the vehicle's entire circuit. Specifically, when the first electrical center 800 is controlled to disconnect, the power supply circuit of the first battery 200 is disconnected. When the second electrical center 900 is controlled to disconnect, the power supply circuit of the second battery 300 is disconnected.

[0098] Furthermore, the control method further includes, as Figure 3 shown, before determining whether the ambient temperature is less than the temperature threshold, it is determined whether the first battery and the second battery are in a failure state according to the battery information. If the deviation of the battery performance parameter from its normal value exceeds the set deviation range, it indicates that the battery has failed, and the reasons may be battery aging, vehicle collision or short column detachment, etc.

[0099] If it is determined that the first battery is in a failure state, the power supply circuit of the first battery is disconnected by controlling the first electrical center to disconnect. If it is determined that the second battery is in a failure state, the power supply circuit of the second battery is disconnected by controlling the second electrical center to disconnect. At the same time, the control module makes a control response accordingly. If both batteries fail, both are disconnected. If one of the batteries fails, the power supply to the vehicle load is borne by the other battery. When the first battery fails, the control mode of the control module switches to the Mode 2 state. When the second battery fails, the control mode of the control module switches to the Mode1 state.

[0100] Adopting the above solution, a redundant power supply system is designed. When one battery fails in the dual-power supply system, the other battery can perform redundant power supply to ensure driving safety.

[0101] Embodiment 4

[0102] Based on the above Embodiment 1, 2 or 3, the dual-power supply system is also communicatively connected to a prompting device, and the prompting device is used to receive and display the prompting information transmitted by the control device. Specifically, the prompting device may include a mobile terminal (such as a mobile phone) and the vehicle's instrument panel. The control device can transmit the prompting information to the corresponding application APP on the mobile terminal through T-BOX, and transmit the prompting information to the instrument panel human-machine interface (HMI) through the vehicle bus to remind the user.

[0103] Further, the control method further includes: in a low-temperature working condition, if the state of charge of the second storage battery is sufficient and in a high state-of-charge range, normal power supply is provided; when the state of charge of the second storage battery is less than or equal to the second sufficient threshold and greater than the second discharged threshold, it indicates that the state of charge is in a medium state-of-charge range, and a prompt message is sent through a prompt device on the basis of normal power supply to prompt to start the vehicle as soon as possible; when the state of charge of the second storage battery is less than or equal to the second discharged threshold, a prompt message is sent through the prompt device to prompt the driver to contact the 4S store to perform pump power rescue as soon as possible.

[0104] In a normal-temperature working condition, when the power of the dual storage batteries is insufficient, that is, when the state of charge of the first storage battery is less than or equal to the first redundancy threshold and greater than the first discharged threshold, and the state of charge of the second storage battery is less than or equal to the second discharged threshold, a prompt message is sent through the prompt device to prompt to start the vehicle as soon as possible; or, when the state of charge of the first storage battery is less than or equal to the first discharged threshold, and the state of charge of the second storage battery is less than or equal to the second discharged threshold, a prompt message is sent through the prompt device to prompt to perform pump power rescue as soon as possible.

[0105] More specifically, regardless of the normal-temperature working condition or the low-temperature working condition, in the sleep mode, a prompt message is sent through the mobile terminal; in the parking mode or the start mode, a prompt message is sent through the instrument panel.

[0106] Based on the solution of Embodiment 2, in this embodiment, taking the first storage battery as a lithium iron phosphate storage battery (Bat Li ) and the second storage battery as a lead-acid storage battery (Bat Pb ) as an example, the first sufficient threshold is SOC e_Li , the first redundancy threshold is SOC r_Li , the first discharged threshold is SOC f_Li , the second sufficient threshold is SOC e_Pb , the second discharged threshold is SOC f_Pb , when, the specific control method (including sending a prompt message, that is, the human-computer interaction method) under different power supply modes is specifically shown in Table 2-4. Among them, SOC_BatLi in the table represents the state of charge of the lithium iron phosphate storage battery, SOC_BatPb represents the state of charge of the lead-acid storage battery, and the smaller the number of the energy distribution priority level in the table, the higher the priority level.

[0107] Table 2 Dual-power energy distribution method in sleep mode

[0108]

[0109] It should be noted that in this mode, the dual-power system mainly supplies power to the controllers of the vehicle loads.

[0110] Table 3 Dual-power energy distribution method in parking mode

[0111]

[0112]

[0113] Table 4. Dual-power energy distribution method for startup mode

[0114]

[0115] It should be noted that in this mode, the dual-power system mainly supplies power to the startup circuit through the startup control module.

[0116] With the above solution, a reasonable human-computer interaction solution is proposed for the scenario of low battery power of the battery, reminding the user to start the vehicle in time and reducing the risk of battery discharge.

[0117] Although the present invention has been illustrated and described by referring to some preferred embodiments of the present invention, those of ordinary skill in the art should understand that the above content is a further detailed description of the present invention in combination with specific embodiments, and it cannot be determined that the specific implementation of the present invention is only limited to these descriptions. Those skilled in the art can make various changes in form and details, including making several simple deductions or substitutions, without departing from the spirit and scope of the present invention.

Claims

1. A control method for a dual - power system of an electric vehicle, the dual - power system including a first storage battery and a second storage battery, characterized in that, The deep discharge capacity of the first storage battery is greater than that of the second storage battery; the control method includes: Obtain storage battery information, where the storage battery information includes the ambient temperature of the first storage battery and the state of charge of the first storage battery and the second storage battery; Judge whether the ambient temperature of the first storage battery is less than the temperature threshold; If so, it is determined that the dual-power supply system is in a low-temperature working condition, and the second storage battery supplies power to the vehicle load; If not, it is determined that the dual-power supply system is in a normal-temperature working condition, and the vehicle power supply mode is obtained, and the dual-power supply system is controlled to supply power to the vehicle load according to the state of charge of the first storage battery and the second storage battery and the vehicle power supply mode. Among them, When the vehicle power supply mode is the driving mode, the direct current-direct current converter supplies power to the vehicle load; and the direct current-direct current converter charges the first storage battery and the second storage battery; When the vehicle power supply mode is the parking mode, the sleep mode or the start mode, where When the state of charge of the first storage battery is greater than the first redundancy threshold, at least the first storage battery supplies power to the vehicle load; When the state of charge of the first storage battery is less than or equal to the first redundancy threshold and the state of charge of the second storage battery is greater than the second discharge threshold, the second storage battery supplies power to the vehicle load; When the state of charge of the first storage battery is less than or equal to the first redundancy threshold and greater than the first discharge threshold, and the state of charge of the second storage battery is less than or equal to the second discharge threshold, the first storage battery supplies power to the vehicle load; When the state of charge of the first storage battery is less than or equal to the first discharge threshold and the state of charge of the second storage battery is less than or equal to the second discharge threshold, the first storage battery supplies power to the vehicle load; where The first redundancy threshold is greater than the first discharge threshold, and the first discharge threshold is less than the second discharge threshold.

2. The control method according to claim 1, characterized in that, The vehicle load includes an entertainment load with entertainment functions and a safety load with safety functions; where In the parking mode, When the state of charge of the first storage battery is greater than the first full charge threshold, the first storage battery supplies power to the vehicle load; When the state of charge of the first storage battery is greater than the first redundancy threshold and less than the first full charge threshold, and the state of charge of the second storage battery is greater than the second discharge threshold, the first storage battery supplies power to the safety load, and the second storage battery supplies power to the entertainment load; When the state of charge of the first storage battery is greater than the first redundancy threshold and less than the first full charge threshold, and the state of charge of the second storage battery is less than or equal to the second discharge threshold, the first storage battery supplies power to the vehicle load; When the state of charge of the first storage battery is less than or equal to the first discharge threshold and the state of charge of the second storage battery is less than or equal to the second discharge threshold, the first storage battery supplies power to the safety load, and the entertainment load is disconnected; In the sleep mode or the start mode, when the state of charge of the first battery is greater than the first redundancy threshold, the first battery supplies power to the vehicle load; when the state of charge of the first battery is less than or equal to the first discharged threshold and the state of charge of the second battery is less than or equal to the second discharged threshold, the first battery supplies power to the safety load and the entertainment load is disconnected; wherein, the first full threshold is greater than the first redundancy threshold.

3. The control method according to claim 1, characterized in that, The battery information further includes the battery health of the first battery and the second battery; the control method further includes, before determining whether the ambient temperature is less than the temperature threshold, determining whether the first battery and the second battery are in a failed state according to the battery information; if it is determined that the first battery is in a failed state, disconnect the power supply circuit of the first battery; if it is determined that the second battery is in a failed state, disconnect the power supply circuit of the second battery.

4. The control method according to claim 1, characterized in that, The control method further includes: in the low temperature condition, when the state of charge of the second battery is less than or equal to the second full threshold and greater than the second discharged threshold, a prompt message is sent through the prompt device to prompt to start the vehicle as soon as possible; when the state of charge of the second battery is less than or equal to the second discharged threshold, a prompt message is sent through the prompt device to prompt to perform pump power rescue as soon as possible; in the normal temperature condition, when the state of charge of the first battery is less than or equal to the first redundancy threshold and greater than the first discharged threshold, and the state of charge of the second battery is less than or equal to the second discharged threshold, a prompt message is sent through the prompt device to prompt to start the vehicle as soon as possible; when the state of charge of the first battery is less than or equal to the first discharged threshold and the state of charge of the second battery is less than or equal to the second discharged threshold, a prompt message is sent through the prompt device to prompt to perform pump power rescue as soon as possible; wherein, the second full threshold is greater than the second discharged threshold.

5. The control method according to claim 4, characterized in that,The prompt device includes a mobile terminal and a dashboard; wherein, in the sleep mode, a prompt message is sent through the mobile terminal; in the parking mode or the start mode, a prompt message is sent through the dashboard.

6. The control method according to claim 2, characterized in that, The control method further includes: in the start mode, the start control module connected in parallel with the safety load turns on the start circuit so that the first battery or the second battery supplies power to the start circuit.

7. The control method according to any one of claims 1-6, characterized in that, The first battery is a lithium iron phosphate battery, and the second battery is a lead-acid battery.

8. A dual-power system for an electric vehicle, characterized in that, Execute the control method of the dual power supply system of the electric vehicle according to any one of claims 1-7; the dual power supply system includes: a control module, the control module obtains the vehicle power mode and is connected to the vehicle load through a load node; a first battery and a second battery, the deep discharge capacity of the first battery is greater than that of the second battery; and the first battery is connected to the control module through a first node, and the second battery is connected to the control module through a second node; A battery information acquisition module, which is connected to the first storage battery and the second storage battery, and is used to acquire battery information. The battery information includes the ambient temperature of the first storage battery, and the state of charge of the first storage battery and the second storage battery. The battery information acquisition module is also communicatively connected to the control module to transmit the battery information to the control module; A DC-DC converter, which is connected to the control module through a third node; wherein, The control module controls the conduction state of the dual power supply system according to the vehicle power supply mode and the battery information to control the dual power supply system to supply power to the vehicle load. Among them, When controlling the first node to conduct with the load node and the second node and the third node to be disconnected, the first storage battery supplies power to the vehicle load; When controlling the second node to conduct with the load node and the first node and the third node to be disconnected, the second storage battery supplies power to the vehicle load; When controlling the first node, the second node, the third node and the load node to conduct, the DC-DC converter supplies power to the vehicle load, and the DC-DC converter charges the first storage battery and the second storage battery.

9. The dual-power system according to claim 8, characterized in that, The vehicle load includes an entertainment load with entertainment functions and a safety load with safety functions. The load node includes a fourth node and a fifth node; the entertainment load is connected to the control module through the fourth node, and the safety load is connected to the control module through the fifth node; wherein, When controlling the first node to conduct with the fifth node, the second node to conduct with the fourth node, and the third node to be disconnected, the first storage battery supplies power to the safety load, and the second storage battery supplies power to the entertainment load; When controlling the first node to conduct with the fifth node, and the second node, the fourth node and the third node to be disconnected, the first storage battery supplies power to the safety load, and the entertainment load is disconnected.

10. The dual-power system according to claim 8, characterized in that, The battery information further includes the battery health of the first storage battery and the second storage battery. The battery information acquisition module includes a battery management system and a battery current sensor; wherein, The battery management system is connected to the first storage battery and is used to acquire the ambient temperature, state of charge and battery health of the first storage battery; the battery current sensor is connected to the second storage battery and is used to acquire the state of charge and battery health of the second storage battery; The dual power supply system further includes a first electrical center and a second electrical center. The first electrical center is connected to the first storage battery, and the second electrical center is connected to the second storage battery; when controlling the first electrical center to be disconnected, the power supply circuit of the first storage battery is disconnected; when controlling the second electrical center to be disconnected, the power supply circuit of the second storage battery is disconnected.

11. The dual-power system according to any one of claims 8-10, characterized in that, The dual power supply system is also connected to a prompt device and a start control module; wherein, The prompt device is connected to the control device and is used to receive and display the prompt information transmitted by the control device; the prompt device includes a mobile terminal and an instrument panel; The start control module is connected in parallel with the safety load and is used to turn on the start circuit when the vehicle power supply mode is in the start mode.

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