Brake energy unloading device for electric vehicle

Abstract

The invention discloses a brake energy unloading device for an electric vehicle, and aims to solve the potential safety hazard of regenerative braking failure of large, medium and small electric vehicles due to saturated charging of batteries. The energy discharger comprises a vehicle-mounted special brake resistor assembly and a control module. When the control module monitors that the state of charge (SOC) of the battery reaches a preset high threshold value and the electric vehicle is in a regenerative braking working condition, the control circuit switches regenerative electric energy generated by the motor from a charging loop to the resistor assembly, the regenerative electric energy is converted into heat energy to safely dissipate redundant electric energy, and the motor continues to generate electricity and do work. The controllable and continuous auxiliary braking torque is provided through multi-stage or stepless adjustment of the resistance value, the effect similar to engine braking is given to the electric vehicle, the safety of the electric vehicle under the working conditions of long downhill and the like is remarkably improved, mechanical braking abrasion is reduced, and passive overcharge of a storage battery is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of new energy vehicles, in particular to the brake energy management technology of vehicles, and more specifically to a brake energy dissipation device specially used for electric vehicles and a control system and method thereof. BACKGROUND

[0002] With the increasing emphasis on environmental protection and energy sustainability worldwide, new energy vehicles, especially pure electric vehicles, have become an inevitable trend in the development of the automotive industry. One of the core advantages of electric vehicles over traditional internal combustion engine vehicles is their energy recovery capability. When the vehicle brakes, decelerates or descends, its drive motor can seamlessly switch to generator mode, converting the vehicle's huge kinetic energy or gravitational potential energy into electrical energy and charging the vehicle's energy storage device (usually a power battery), a process known as "regenerative braking". Regenerative braking technology not only significantly improves the vehicle's energy utilization efficiency, effectively increasing the range, but also participates in the vehicle's deceleration process, to some extent, reducing the burden on the traditional mechanical brake system.

[0003] In the field of electric passenger cars, the application of regenerative braking technology is quite mature and perfect. Passenger cars, due to their relatively small mass and rated load, can often achieve a dynamic balance between energy consumption and recovery when driving under normal urban or mixed conditions, i.e. the energy recovered by regenerative braking is far from enough to fully charge the battery. Even in some special cases, such as long downhill driving leading to battery charge close to saturation, the vehicle's battery management system (BMS) and vehicle controller (VCU) will actively take protective measures, i.e. reduce or completely shut down the regenerative braking function, at which time the vehicle's braking task will be completely taken over by the traditional hydraulic or pneumatic mechanical brake system. Since the total mass of a passenger car is controllable, relying on mechanical brakes for a short time usually does not pose a serious safety problem. However, manufacturers still advise users in the manual not to charge too full when charging, preferably to 90% to 95%, leaving 5~10% for recovered energy. However, when this mature technology is directly transplanted to commercial vehicles, especially heavy electric trucks, it exposes serious technical defects and safety hazards. The fundamental reason lies in the huge difference in operating conditions and physical characteristics between commercial vehicles and passenger cars: First, the mass difference is huge. Electric trucks, especially when fully loaded, can have a total mass of tens of tons, several times or even tens of times that of a passenger car. This means that at the same speed, its kinetic energy grows exponentially; when descending, its gravitational potential energy is also extremely large.

[0004] Second, the mismatch between battery capacity and braking energy. Although the battery capacity of a truck is usually larger than that of a passenger car, its growth rate is much lower than that of the total mass of the vehicle. Therefore, in the case of strong braking or long downhill working conditions, the instantaneous or sustained regenerative electric energy will very quickly fill the battery. If too much charging space is reserved, the endurance will be greatly reduced.

[0005] Third, the extremity of specific working conditions. Freight tasks often involve crossing mountainous areas or going back and forth in areas with significant altitude differences, such as mining areas. For example, heavy loads descending from high-altitude mining areas to low-altitude areas is a typical "net energy input" process. In such working conditions, the battery will quickly reach the upper limit of charging (state of charge SOC close to 100%) in a short time.

[0006] Once the battery is full, the BMS will forcibly cut off the charging circuit to protect the battery from overcharging damage, resulting in the complete failure of the regenerative braking function. At this time, the only means of deceleration left for the driver is the mechanical brake system (such as oil brakes or air brakes). If a truck weighing several dozen tons relies solely on mechanical brakes during long downhill driving, a large amount of heat energy will be generated between the brake shoes / pads and the brake drums / pads due to long-term and intense friction, and the temperature can rise sharply to several hundred degrees Celsius. This can easily lead to "thermal recession" of brake performance, i.e., a significant decrease in braking force, and in severe cases, even complete failure, thereby causing catastrophic traffic accidents. Currently, some manufacturers try to install brake water cooling devices to cool the brake system, but this is a passive and symptomatic remedy that not only consumes water resources but also faces the risk of icing in winter, and cannot fundamentally solve the problem of dissipation of braking energy.

[0007] Therefore, there is an urgent need to solve the gap in existing electric vehicle technology: when regenerative braking fails due to battery saturation, how to provide a safe, reliable, simple, and continuous auxiliary braking method for the vehicle to avoid excessive reliance on mechanical brakes. This problem is particularly deadly for heavy trucks, but it also poses a safety hazard for medium and light electric trucks and medium and large electric passenger cars that perform high-frequency logistics or transport on hilly roads. SUMMARY

[0008] The purpose of the present application is to overcome the above-mentioned defects of the prior art and provide an electric vehicle brake de-energizer and its control system and method, which aims to provide a continuous electric braking function equivalent to the "engine braking" or "hydrodynamic retarder" of traditional fuel vehicles for large, medium, and small electric vehicles after the battery is full, thereby fundamentally solving the safety hazard during long downhill or heavy load braking.

[0009] To achieve the above object, the application provides an electric vehicle brake de-energizer, comprising: a brake resistance assembly, the brake resistance assembly comprising at least two groups of independently controllable power resistance units and a box for isolating resistance heat and orderly heat dissipation; a control module, the control module being in communication connection with a vehicle controller and / or a battery management system of the vehicle; wherein the control module is used for acquiring real-time state of charge information of a vehicle storage battery (6) and brake demand information of the vehicle; when the control module judges that the state of charge information of the storage battery (6) reaches or exceeds a preset first threshold value, and the electric vehicle (5) is in a regenerative braking power generation state, the control module controls a switching circuit, according to the brake demand information, by selectively combining the multiple groups of power resistance units in series, in parallel or independently, to form multiple different equivalent total resistance values, so as to guide the electric energy generated by the driving motor to the brake resistance assembly, and realize multi-stage adjustable brake energy dissipation.

[0010] Further, each group of power resistance units in the brake resistance assembly comprises at least one large-power U-shaped resistance (12) with fins; the pipe body (20) of the large-power U-shaped resistance (12) with fins is provided with a resistor helical fin (19) to increase the heat dissipation surface area and strengthen the convective heat exchange; the tail end of the large-power U-shaped resistance (12) with fins is fixed in the box through a resistance U-shaped pipe tail fixing plate (15) or a resistance U-shaped pipe tail fixing ring (26).

[0011] Further, the switching circuit comprises a large-power relay or contactor; and the multi-stage adjustable brake energy dissipation is realized by controlling the relay or contactor to selectively switch the multiple groups of power resistance units (12) into one of a delta connection, a double star connection, a two-series star connection, a delta / star hybrid connection, a three-series star connection or a three-parallel star connection.

[0012] The electric vehicle brake de-energizer provided by the application can further comprise: a vehicle-mounted special brake resistance assembly comprising at least one power resistance unit (12) and a box for heat dissipation; a switching circuit comprising power electronic switching devices; a control module; wherein when the control module judges that the SOC of the storage battery (6) reaches a preset threshold value and the electric vehicle (5) is in a regenerative braking state, the control module controls the on-duty ratio of the power electronic switching devices by generating a pulse width modulation (PWM) signal, so as to continuously and smoothly adjust the average current flowing into the brake resistance assembly, thereby realizing stepless adjustment of the brake torque.

[0013] Further, the power electronic switching device is an insulated gate bipolar transistor (IGBT); the power resistor unit in the brake resistor assembly comprises at least one finned high-power U-shaped resistor (12).

[0014] Further, the brake resistor assembly has one of the following structural features: (a) the box body is provided with a longitudinal energy discharger air inlet shunt cover (17) and a longitudinal air collecting cavity (18); the air inlet shunt cover (17) is used for guiding external airflow into the air collecting cavity (18), and the air collecting cavity (18) is used for forming stable airflow in front of the power resistor unit (12) to concentrate and efficiently dissipate heat; or (b) the energy discharger is a vertical torch-shaped energy discharger (3), and the torch-shaped energy discharger box body (27) is vertically arranged, and the outer cylindrical surface of the box body (27) is covered with ventilation holes (29) to form direct convection heat dissipation by using airflow in different directions when the resistor (12) generates heat.

[0015] Further, the brake resistor assembly has one of the following structural features: (a) the energy discharger is a water tank position energy discharger (1), and the water tank position energy discharger box body (34) is arranged on the windward surface of the electric vehicle (5), and the box body (34) is provided with a water tank position energy discharger ventilation hole (33) to forcibly dissipate heat by using vehicle driving wind; or (b) the energy discharger is a vehicle bottom longitudinal energy discharger (7), and a forced heat dissipation fan is arranged at the air inlet (25) of the longitudinal energy discharger to provide sufficient heat dissipation capacity when the vehicle is running at low speed.

[0016] Further, the electrical connection of the power resistor unit (12) is led out through the resistor terminal post (13) and is accommodated in the terminal box composed of the energy discharger terminal box cover (36) and the energy discharger terminal port (37); the brake demand information at least includes one or more of the speed control pedal zero return, brake pedal opening degree, vehicle deceleration or slope sensor signal; the rated dissipation power of the energy discharger is between 40% and 120% of the rated power of the driving motor of the electric vehicle (5).

[0017] The application also provides a brake braking control system applied to an electric vehicle, characterized in that the brake braking control system comprises the above brake braking energy discharger.

[0018] The application also provides a brake braking control method of an electric vehicle, comprising the following steps: Step S1: Real-time monitoring of the state of charge information of the vehicle battery (6) and the brake demand level of the vehicle; Step S2: Determining whether the state of charge information is greater than or equal to a preset saturation threshold; Step S3: If the judgment is yes, when the electric vehicle (5) generates regenerative braking energy, according to the braking demand level, a switching circuit is controlled to guide the energy to the brake resistance assembly for dissipation; the dissipation control mode is one of the following two modes: (a) by selectively connecting, connecting in parallel or independently connecting a plurality of power resistance units (12) in the brake resistance assembly to form a plurality of different equivalent total resistance values (such as delta connection, star connection or mixed connection), to realize multi-level adjustable braking energy dissipation; or (b) by generating a pulse width modulation (PWM) signal to control the on-duty ratio of the power electronic switching device in the switching circuit, to continuously and smoothly adjust the average current flowing into the brake resistance assembly, to realize stepless adjustment of the braking torque.

[0019] Compared with the prior art, the present application has the following remarkable beneficial effects: 1) The safety is fundamentally improved: the present application provides an electric vehicle with a powerful auxiliary electric braking system that is still effective after the battery is fully charged. It solves the problem from the source of energy conversion, avoids excessive dependence on mechanical brakes due to the failure of regenerative braking, thereby eliminating the risk of mechanical brake heat recession, especially in high-risk working conditions such as mountainous areas and heavy loads, providing a decisive guarantee for driving safety.

[0020] 2) Reduce operating and maintenance costs: since the energy unloader of the present application bears a large amount of braking energy dissipation task, it greatly reduces the burden of the mechanical brake system. This directly translates into a significant reduction in the wear and tear of vulnerable parts such as brake pads and brake discs, extending their service life and reducing the frequency of replacement and related maintenance costs.

[0021] 3) Expand the application range of electric trucks: the present application solves the core shortcoming of electric vehicles in complex geographical environments, enabling them to safely and efficiently serve in fields such as mountainous area freight transportation and mine transportation, which were previously considered "no-go areas", greatly expanding their market application scenarios.

[0022] 4) Simple structure and high reliability: the core part of the entire energy unloader has no mechanical moving parts, mainly composed of mature resistance elements, heat dissipation structures and electronic control units, with high reliability, long service life and low maintenance requirements, easy to integrate and install.

[0023] 5) Improve battery utilization: it can make all kinds of electric vehicles leave the charging space without emphasizing the need to reserve the charging space, and increase the total endurance capacity when leaving with a full battery.

[0024] 6) The invention is mainly designed for the safety defects of heavy electric trucks, but also applies to small and medium-sized electric trucks, small passenger cars, and large and medium-sized long-distance electric passenger cars under development, giving a controllable release channel for regenerative electric energy, protecting the battery, and perfecting the brake technology closed loop of electric vehicles. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0026] Figure 1 is an application diagram of the electric vehicle brake de-energizer in the embodiment of the present application; Figure 2 is a multi-angle application diagram of the electric vehicle brake de-energizer in the embodiment of the present application; Figure 3 is a structure schematic diagram of a roof box de-energizer in the embodiment of the present application; Figure 4 is a structure schematic diagram of a longitudinal flat box de-energizer in the embodiment of the present application; Figure 5 is a structure schematic diagram of a torch-shaped de-energizer in the embodiment of the present application; Figure 6 is a structure schematic diagram of a water tank de-energizer in the embodiment of the present application; Figure 7 is a structure schematic diagram of a longitudinal de-energizer in the embodiment of the present application; Figure 8 is a three-phase star / delta connection variable resistance circuit diagram of the de-energizer in the embodiment of the present application; Figure 9 is a three-phase delta / star hybrid connection circuit diagram of the de-energizer in the embodiment of the present application.

[0027] Figure: 1, water tank position energy discharger; 2, roof position energy discharger; 3, vertical torch-shaped energy discharger; 4, vehicle tank bottom position vertically placed flat-shaped energy discharger; 5, electric vehicle; 6, battery box; 7, vehicle tank bottom position vertically placed energy discharger; 8, roof position energy discharger outlet; 9, roof position energy discharger protective cover; 10, roof position energy discharger air inlet; 11, roof position energy discharger heat dissipation air outlet (surface); 12, large power U-shaped resistor with fins; 13, resistor terminal post; 14, roof tank body; 15, resistor U-shaped tube tail fixing plate; 16, vertically placed energy discharger inlet pipe flange plate; 17, vertically placed energy discharger air inlet shunt cover; 18, vertically placed gas collecting cavity; 19, resistor helical fin circular cross section; 20, resistor tube body cross section; 21, vehicle bottom flat tank body; 22, vertically placed energy discharger heat dissipation air outlet; 23, vehicle bottom position energy discharger tank cover; 24, vertically placed energy discharger mounting surface; 25, vertically placed energy discharger air inlet; 26, resistor U-shaped tube tail fixing ring; 27, torch-shaped energy discharger tank body; 28, torch-shaped energy discharger tank cover; 29, torch-shaped energy discharger air vent; 30, torch-shaped energy discharger inlet pipe stand; 31, torch-shaped energy discharger mounting flange plate; 32, water tank position resistor mounting flower plate; 33, water tank position energy discharger air vent; 34, water tank position energy discharger tank body; 35, water tank position mounting plate; 36, energy discharger terminal box cover; 37, energy discharger terminal port; 38, vertically placed energy discharger tank rear cover; 39, vertically placed energy discharger tank body DETAILED DESCRIPTION The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0028] Embodiment one: application and installation layout of energy discharger system Please refer to Figure 1 and Figure 2 , which show various installation application examples of the electric vehicle brake discharger of the present application on the electric vehicle (5). The core purpose of the present application is to provide an energy dissipation path independent of the battery when the state of charge (SOC) of the battery in the vehicle battery box (6) reaches saturation (such as more than 95%), so as to continue the regenerative braking function and avoid overheating of the mechanical brake.

[0029] In order to adapt to the chassis and body structure of different electric vehicles (5), the present application provides energy discharger assemblies in various installation forms: 1) water tank position energy discharger (1): installed at the position of the traditional water tank radiator of the vehicle head, which can fully utilize the Ram-Air during vehicle driving for high-efficiency forced heat dissipation.

[0030] 2) Roof-mounted heat dissipation device (2): Installed on the top of the cab, it utilizes the open space at a high position for heat dissipation and does not occupy chassis space.

[0031] 3) Vertical torch-shaped energy release device (3): For example, it is installed at the rear of the cab or on the side of the car body, and uses the vertical structure to promote natural air convection in different directions.

[0032] 4) The longitudinally placed flat energy dissipator at the bottom of the vehicle body (4): is installed under the chassis between the frame beams where the chassis space is limited (it can also be used for small passenger cars) to dissipate heat by utilizing the airflow under the vehicle body.

[0033] 5) Longitudinal energy unloader at the bottom of the vehicle body (7): It is also installed on the chassis and is another type of longitudinal installation structure.

[0034] All of these de-energizers are connected via circuitry to the vehicle's motor controller (MCU) and vehicle control unit (VCU).

[0035] Example 2: Specific Structure of the Energy Discharger Assembly Figures 3 to 7 The specific structures of the above-mentioned installation methods are shown. The core component they share is a finned high-power U-shaped resistor (12), which is the main element for converting electrical energy into heat energy.

[0036] 1. Rooftop energy unloader ( Figure 3 ):correspond Figure 1 The roof-mounted energy release device (2) is located in the vehicle. Its structure includes a roof box (14), on which a roof-mounted energy release device air inlet (10) and a roof-mounted energy release device heat dissipation outlet (face) (11) are provided, forming a through airflow channel. A U-shaped resistor (12) is horizontally installed inside the box (14), and its tail end is reliably fixed by a resistor U-shaped tube tail fixing plate (15) to resist vehicle vibration. The electrical connection is led out through the resistor terminal (13) and protected by the roof-mounted energy release device outlet (8) and the roof-mounted energy release device protective cover (9) to ensure high-voltage safety and waterproof performance.

[0037] 2. Undercarriage longitudinally mounted flat box energy unloader ( Figure 4 ):correspond Figure 1 , 2The vehicle body is equipped with a longitudinally mounted flat energy discharger (4) at the bottom. This is a highly efficient design that utilizes airflow under the vehicle. It includes a flat box body (21) at the bottom, with the top closed by a cover (23) for the energy discharger. Its key feature is its airflow management system: airflow under the vehicle enters through the air inlet (25) of the longitudinally mounted energy discharger, first passing through the air inlet shroud (17) of the longitudinally mounted energy discharger, which guides the airflow evenly to the longitudinally mounted air-gathering chamber (18). The function of the air-gathering chamber (18) is to create a stable pressure for the airflow before it enters the resistance zone, and then flow at high speed and in a concentrated manner through the fins of multiple finned high-power U-shaped resistors (12), and finally exit from the heat dissipation outlet (22) of the longitudinally mounted energy discharger. This design greatly improves the heat dissipation efficiency. Furthermore, as shown in the figure, the resistor tube section (20) of the finned high-power U-shaped resistor (12) can be equipped with resistor spiral fins (19). The spiral structure can generate turbulence when the airflow passes through, further destroying the thermal boundary layer and enhancing the heat transfer effect. The finned high-power U-shaped resistor (12) is fixed by the resistor U-shaped tube tail fixing plate (15), and the electrical connection is led out through the resistor terminal (13), and a firm and sealed connection with the external cable is achieved through the longitudinal energy releaser inlet pipe flange (16). The longitudinal energy releaser mounting surface (24) is used to fix it on the frame.

[0038] 3. Torch-shaped energy discharger ( Figure 5 ):correspond Figure 1 The vertical torch-shaped energy releaser (3) is characterized by a vertical cylindrical housing (27) with a torch-shaped energy releaser cover (28) on top. The housing (27) is covered with ventilation holes (29). A finned high-power U-shaped resistor (12) is vertically installed inside the housing and fixed by a resistor U-shaped tube end fixing ring (26). Its beneficial effect is that when the finned high-power U-shaped resistor (12) heats up, the internal air is heated, and air from different directions enters through the corresponding ventilation holes, carries away the heat through the resistor and fins, and is then discharged through the ventilation holes (29) on the opposite side; this design has excellent heat dissipation capacity even when the vehicle is stationary. The electrical connection is led out through the resistor terminal (13) and the torch-shaped energy releaser inlet pipe column (30), and the torch-shaped energy releaser mounting flange (31) is used to securely install it on any side of the vehicle body.

[0039] 4. Water tank level unloader ( Figure 6 ):correspond Figure 1 , 2The water tank position unloader (1) is included. It includes a water tank position unloader housing (34), with dense ventilation holes (33) on the front of the housing, and is fixed to the windward position of the front of the vehicle by a water tank position mounting plate (35). A finned high-power U-shaped resistor (12) (which may also have spiral fins 19 on its tube cross-section 20) is precisely positioned in the housing (34) by a water tank position resistor mounting plate (32) (a perforated fixing plate) and a resistor U-shaped tube tail fixing plate (15). The wiring is led out through the resistor terminal (13) and is sealed and protected by the unloader junction box cover (36) and the unloader wiring port (37).

[0040] 5. Undercarriage longitudinal energy unloader ( Figure 7 ):correspond Figure 2 The longitudinally positioned energy unloader (7) is located at the bottom of the vehicle body. This is a cylindrical structure comprising a longitudinally positioned energy unloader housing (39) and a rear cover (38) for the housing. Its airflow path is similar to... Figure 4 Similar to the longitudinally mounted energy depletor, this includes the inlet flange (16), the inlet diffuser (17), and the air-gathering chamber (18). The finned high-power U-shaped resistor (12) is secured by a resistor U-shaped tube end retaining ring (26). A key feature is that the internal structure of its longitudinally mounted energy depletor inlet (25) resembles a fan blade, indicating that this embodiment can (but is not limited to) integrate an active cooling fan to provide forced air cooling at low speeds or in stationary conditions, ensuring all-weather heat dissipation. The airflow is ultimately exhausted through the longitudinally mounted energy depletor heat dissipation outlet (22).

[0041] Example 3: Multi-level adjustment control (circuit implementation) This invention can achieve multi-level adjustable braking torque by changing the equivalent total value of the resistance. Figure 8 and Figure 9 The circuit principle for achieving this function is demonstrated. The control module (VCU) controls the switching circuit (such as a high-power relay or contactor) to combine the resistor terminals (13) (for three-phase variable resistor wiring) of the de-energizer assembly (e.g., containing three or six sets of resistor units internally) in different ways. Figure 8 As shown, it can be switched to: Delta connection: lower equivalent resistance, larger braking torque.

[0042] Double star connection: equivalent resistance is moderate.

[0043] Two star-shaped connections: high equivalent resistance, low braking torque. For example... Figure 9 As shown, more complex combinations can also be achieved, such as a delta / star hybrid connection, a three-series star connection, or a three-parallel star connection. Its advantages are: the VCU can select different connections (gears) according to the brake pedal opening or vehicle deceleration requirements, achieving effects similar to the 1st, 2nd, and 3rd gears of "engine braking" in a gasoline vehicle, with a simple and reliable structure.

[0044] Example 4: Stepless Adjustment Control (Circuit Implementation) This invention enables continuous and smooth stepless adjustment. In this manner, the energy discharger assembly (such as...) Figures 3-7 A finned high-power U-shaped resistor (12) shown in any of the above can be used as a set of fixed loads (e.g., always kept at a constant load). Figure 8 (The delta connection method). The control module (VCU) controls a high-power power electronic switching device (such as an IGBT module) by generating a pulse width modulation (PWM) signal. By adjusting the duty cycle (0%-100%) of the PWM signal, the VCU can continuously and smoothly control the average current flowing into the finned high-power U-shaped resistor (12), thereby achieving stepless adjustment of the braking torque from 0 to its maximum value. Its beneficial effects are: extremely fast response speed (microsecond level), extremely smooth control, no shift shock, and deep collaboration with ABS, ESP and other systems to achieve more advanced vehicle dynamics management.

[0045] Example 5: Braking Control Method In conjunction with the aforementioned hardware, the control method of the present invention is executed by the VCU and includes: 1) Real-time monitoring of the SOC status of the battery box (6) and the vehicle's braking requirements (such as pedal opening, vehicle speed, and gradient).

[0046] 2) Determine whether the SOC is greater than or equal to the preset saturation threshold (e.g., 95%).

[0047] 3) If the judgment is "yes" and the vehicle needs to brake (such as releasing the accelerator or pressing the brake), the VCU immediately activates the energy dissipation system.

[0048] 4) The VCU switches the regenerative electrical energy generated by the motor to the energy discharger assembly (such as any one of 1, 2, 3, 4, or 7) according to the braking demand level.

[0049] 5) At the same time, the VCU, according to requirements: (Multi-level mode): Controls the relay to select one such level. Figure 8 or Figure 9 The resistor connection settings are shown.

[0050] (Stepless Mode): Outputs a PWM signal with a specific duty cycle to the IGBT.

[0051] 6) Electrical energy is introduced into a finned high-power U-shaped resistor (12) and quickly converted into heat energy.

[0052] 7) Heat energy is efficiently dissipated into the atmosphere through specific structures of the energy release assembly (such as air intake splitter (17), air collection chamber (18), ventilation hole (29) or ventilation hole (33)) to complete the auxiliary braking process.

[0053] The above merely provides the preferred embodiments of the present application, but not intended to limit the present application. The present application can be variously changed and modified by those skilled in the art. Any modification, equivalent replacement, improvement, etc. (such as changing the resistance shape and resistance material) made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An electric vehicle brake de-energizer characterized by, Comprise: A brake resistance assembly, the brake resistance assembly contains at least two groups of independently controllable power resistance units and a box for isolating resistance heat and orderly heat dissipation; A control module, the control module is connected with the vehicle controller and / or battery management system of the vehicle; Wherein, the control module is used for real-time acquisition of the state of charge information of the vehicle storage battery (6) and the braking demand information of the vehicle; When the control module judges that the state of charge information of the storage battery (6) reaches or exceeds the preset first threshold value, and the electric vehicle (5) is in the regenerative braking power generation state, the control module controls a switching circuit, according to the braking demand information, by selectively connecting, parallel or independent access combination of the multiple groups of power resistance units, to form multiple different equivalent total resistance values, so as to guide the electric energy generated by the driving motor to the brake resistance assembly, and realize multi-stage adjustable brake energy dissipation.

2. The energy offloader of claim 1, wherein, Each group of power resistance units in the brake resistance assembly comprises at least one finned high-power U-shaped resistance (12); The pipe body (20) of the finned high-power U-shaped resistance (12) is provided with a resistor spiral fin (19) to increase the heat dissipation surface area and strengthen the convective heat transfer; The tail end of the finned high-power U-shaped resistance (12) is fixed in the box through the resistance U-shaped pipe tail fixing plate (15) or the resistance U-shaped pipe tail fixing ring (26).

3. The energy offloader of claim 1, wherein, The switching elements in the switching circuit are high-power relays or contactors; And, the multi-stage adjustable brake energy dissipation is realized by controlling the relays or contactors to selectively switch the multiple groups of power resistance units (12) to one of delta connection, double star connection, two series star connection, delta / star mixed connection, three series star connection or three parallel star connection.

4. An electric vehicle brake de-energizer characterized by, Comprise: A vehicle-mounted special brake resistance assembly, which contains at least one power resistance unit (12) and a box for heat dissipation; A switching circuit containing power electronic switching devices; A control module; Wherein, when the control module judges that the SOC of the storage battery (6) reaches the preset threshold value and the electric vehicle (5) is in the regenerative braking state, the control module controls the on-duty ratio of the power electronic switching devices by generating a pulse width modulation signal to continuously and smoothly adjust the average current flowing into the brake resistance assembly, thereby realizing stepless adjustment of the braking torque.

5. The energy absorber of claim 4, wherein, The power electronic switching device is an insulated gate bipolar transistor; The power resistance unit in the brake resistance assembly comprises at least one finned high-power U-shaped resistance (12).

6. The energy dump of claim 1 or 4, wherein, The brake resistance assembly has one of the following structural features: (a) a longitudinal discharging device air inlet shunt cover (17) and a longitudinal gas gathering cavity (18) are arranged on the box, the air inlet shunt cover (17) is used for guiding external airflow into the gas gathering cavity (18), and the gas gathering cavity (18) is used for forming stable airflow in front of the power resistance unit (12) to concentrate and efficiently dissipate heat; or (b) the discharging device is a vertical torch-shaped discharging device (3), the torch-shaped discharging device box (27) is vertically arranged, and the outer cylindrical surface of the box (27) is covered with ventilation holes (29) to form direct convection heat dissipation by using airflow in different directions when the resistance (12) generates heat.

7. The energy dump of claim 1 or 4, wherein, The brake resistance assembly has one of the following structural features: (a) the discharging device is a water tank position discharging device (1), the water tank position discharging device box (34) is arranged on the windward surface of the electric vehicle (5), and the box (34) is provided with a water tank position discharging device ventilation hole (33) to forcibly dissipate heat by using vehicle driving wind; or (b) the discharging device is a vehicle bottom longitudinal discharging device (7), a forced heat dissipation fan is arranged at the air inlet (25) of the longitudinal discharging device to provide sufficient heat dissipation capacity when the vehicle is low-speed or stationary.

8. The energy dump of claim 1 or 4, wherein, The electrical connection of the power resistance unit (12) is led out through the resistor terminal post (13) and is accommodated in the terminal box composed of the discharging device terminal box cover (36) and the discharging device terminal port (37); the brake demand information at least includes one or more of the speed control pedal zero return, brake pedal opening, vehicle deceleration or slope sensor signal; the rated dissipation power of the discharging device is between 40% and 120% of the rated power of the electric vehicle (5) driving motor.

9. A brake control system for an electric vehicle, characterized by comprising: The brake discharging device comprises the brake discharging device according to any one of claims 1 to 8.

10. A brake braking control method of an electric vehicle, characterized by, The method comprises the following steps: Step S1: real-time monitoring of the state of charge information of the vehicle battery (6) and the brake demand level of the vehicle; Step S2: determining whether the state of charge information is greater than or equal to a preset saturation threshold; Step S3: if the determination is yes, when the electric vehicle (5) generates regenerative braking energy, according to the brake demand level, a switching circuit is controlled to guide the energy to the brake resistance assembly for dissipation; the dissipation control mode is one of the following two modes: (a) a plurality of power resistance units (12) in the brake resistance assembly are selectively connected in series, parallel or independently combined to form a plurality of different equivalent total resistance values, so as to realize multi-level adjustable brake energy dissipation; or (b) the on-duty ratio of the power electronic switching device in the switching circuit is controlled by generating a pulse width modulation signal to continuously and smoothly adjust the average current flowing into the brake resistance assembly, so as to realize stepless adjustment of the brake torque.

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