A protection system for a vehicle

Abstract

The invention relates to a protection system for a vehicle comprising at least one vehicle power source (10) for driving the vehicle; a plurality of electrical loads (30) connected to the vehicle power source (10); at least one main power source (40) connected to the vehicle power source (10); at least one circuit breaker (20) for connecting or disconnecting the vehicle power source (10) to the electrical loads (30) and the main power source (40); a control unit (50) in communication with the circuit breaker (20);

Description

A PROTECTION SYSTEM FOR A VEHICLEFIELD OF INVENTON

[0001] The invention relates to a protection system for a vehicle & method and more particularly, it relates to an electrical protection system of associated hardware and battery in automobiles.CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This invention takes priority from an earlier filed provisional patent application no. 202421097165 filed on December 09, 2024; which is incorporated herein as reference.BACKGROUND OF THE INVENTION

[0003] Automobiles equipped with batteries and fuses are fundamental in ensuring the proper supply and management of load current to various electrical components. The battery serves as the primary energy source, while the fuse acts as a safety device to protect electrical circuits from overcurrent or short circuits. This includes starting the internal combustion engines, driving the motor for electric vehicles, operating lights, and other auxiliary functions. Modern vehicles also rely on the battery to power advanced electronics, such as sensors and control systems that control various aspects of vehicle operation.

[0004] Conventional fuses are installed in the electrical system to protect circuits from overloading. When excessive current flows through a circuit due to a fault or short circuit, the fuse's filament melts, breaking the circuit and preventing damage to components or the risk of fire. Fuses come in various types and ratings to match specific circuits, ensuring precise protection tailored to the current demands of each system.

[0005] The integration of batteries and fuses ensures seamless operation and safety. For instance, when starting the car, the battery provides a surge of current to the starter motor. Fuses safeguard against potential overcurrent caused by a malfunction in the starter circuit. Similarly, for systems like headlights or auxiliary loads, the fuse protects delicate electronics from damage due to unforeseen electrical anomalies.

[0006] Fuses are designed to break the circuit when excessive current flows through it. If a short circuit or fault occurs in a vehicle's electrical system, the battery could rapidly discharge as it tries to supply an unusually high current to the faulted circuit. This can lead to overheating, depletion of battery charge, or even permanent damage to the battery and electrical components. By interrupting the current flow during such instances, the fuse prevents unnecessary battery strain, preserving its lifespan.

[0007] In severe cases, overcurrent may lead to overheating or fire, potentially damaging the battery or other expensive components. The fuse prevents such scenarios by acting as a failsafe, ensuring the battery is not exposed to hazardous conditions that could lead to its degradation.

[0008] The vehicles are generally provided with a 12V auxiliary battery or power source, which are required to provide power to the vehicle control unit (VCU) for starting of the vehicle and also for detecting anti-theft action during vehicle off condition. The 12V auxiliary battery also provides necessary power to various auxiliary components such as headlamps, tail lamps, horn, indicators etc. In the event when excess current flows from the auxiliary battery there is a drain of the battery and the vehicle is unable to start. Hence, protection of auxiliary battery along with other electrical components is of utmost importance.

[0009] Although, Mechanical fuses, while effective at protecting circuits from overcurrent, being cost friendly upfront it comes with several disadvantages. Once a mechanical fuse blows, it cannot be reused and must be physically replaced. This can lead to inconvenience and downtime, especially if the fuse is not easily accessible or if spares are unavailable. Repeated replacement adds to increasing cost. Mechanical fuses are designed with a specific current rating and cannot be adjusted or reset. This lack of flexibility makes it necessary to stock multiple fuse types for different circuits and applications. Mechanical fuses may not provide precise protection against overcurrent conditions. They can be less reliable in distinguishing between transient surges (harmless) and sustained overcurrent conditions.

[0010] Mechanical fuses are not well-suited for applications with dynamic load requirements, such as modern vehicles, due to their fixed operational thresholds. These fuses are designed to blow when the current exceeds a predefined value, but they cannot distinguishbetween temporary surges caused by legitimate load increases and genuine fault conditions. In vehicles, where electrical loads frequently fluctuate like when lighting, or infotainment systems are activated this limitation can lead to unnecessary fuse failures, disrupting the system.

[0011] Additionally, mechanical fuses struggle with handling transient loads, such as the brief spikes in current drawn by electric motors or other high-powered devices. They may interpret these surges as faults, blowing unnecessarily and causing interruptions even when there is no real danger. Conversely, mechanical fuses are often unable to detect gradual overloads, such as those caused by aging components or increased circuit resistance, which can lead to inefficiencies and potential damage over time. These limitations make mechanical fuses less effective for modern automotive systems that demand precise, adaptive protection for complex and variable electrical loads.

[0012] Hence, there is a need to provide a protection system involving an electric fuse that can be operated both electrically and mechanically to detect and control the flow of overcurrent or overvoltage to various loads in an automotive vehicle.OBJECT OF THE INVENTION

[0013] An object of the invention is to limit overcurrent to the load from the battery.

[0014] Another object of the invention is to provide a protection system comprising reusable fuse.

[0015] Yet another object of the invention is to stop drainage of the battery pack.

[0016] A further object is to dynamically adjust the threshold current of fuse from the battery based on the vehicle load.

[0017] Another object of the invention is to provide auxiliary battery health monitoring, energy efficiency, functionality, and reliability in the design of EV systems.

[0018] Yet another object of the invention is to avoid damage to the electric fuse leading to a longer lifespan, economic advantage and mitigating any frequent maintenance requirements.

[0019] Yet another object of the invention is to provide a cost effective & user-friendly electrical protection system for automotive vehicles.

[0020] Still another object of the invention is to overcome lacunas of existing systems explained in background section.SUMMARY OF THE INVENTION

[0021] With the above objectives in view, the present invention provides a protection system for vehicle, comprising at least a vehicle power source for driving the vehicle; a plurality of electrical loads connected to the vehicle power source; at least one main power source connected to the vehicle power source; at least one circuit breaker for connecting or disconnecting the vehicle power source to the electrical loads and the main power source; a control unit in communication with the circuit breaker; wherein the control unit is configured to detect the current or voltage supplied between the vehicle power source, the main power source and the electrical loads and actuate the circuit breaker upon detecting the current or voltage exceeding a predefined threshold limit and time in both vehicle operative and inoperative states.

[0022] The threshold limit of the current and voltage and a predetermined time for disconnection or connection of the circuit breaker is configured based on the vehicle operative and inoperative states and the direction of the current flow to or from the vehicle power source.

[0023] The control unit comprises an adjustment unit configured to dynamically regulate the threshold limit of the current or voltage in response to varying power demands for the vehicle power source and the electric loads basis vehicle operative and inoperative states.

[0024] The vehicle operative states include power and energy states, motion and drive states, location and connectivity states, user interaction states, system and diagnostic states.

[0025] The circuit breaker is in the form of a switch or a fuse or electronically operated fuse comprising semiconductor devices including MOSFET, IGBT or thyristors (SCRs).

[0026] The circuit breaker is provided with a threshold determination unit, which detects current or voltage exceeding threshold level for a predetermined time configured to operate the circuit breaker for disconnection or connection post correction of the condition.

[0027] The circuit breaker comprises a delay & latch circuit to delay and hold signal for a set time and maintains output state until reset for driving at-least one FET drive circuit operating the semiconductor switches.

[0028] The threshold determination unit and the control unit are operatively connected to the circuit breaker.

[0029] The threshold determination unit continuously monitors current and voltage providing feedback to the control unit for the control unit to assess electrical faults.

[0030] The circuit breaker is self-triggered during vehicle inoperative condition in the event that the current or voltage exceeding a predefined threshold limit and time and no signal received from the control unit.

[0031] The circuit breaker comprises of a sensing unit configured to monitor the charging current to the vehicle power source and communicates with control unit for further actions including disconnecting charging based on charging state of the vehicle power source

[0032] The circuit breaker includes a reset pin for overriding any self-trigger or triggers from the control unit.

[0033] The main power source and the vehicle power source are a traction battery and an auxiliary battery, respectively.

[0034] The control unit is a vehicle control unit configured for managing and coordinating the operation of multiple systems, including the powertrain, battery management system (BMS), braking, and thermal management.BRIEF DESCRIPTION OF DRAWINGS:

[0035] The above and other objects, features, and advantages of the present disclosure will be more apparent from the detailed description taken in conjunction with the accompanying drawings. One or more embodiments of the present invention are now described, by way of example only with reference to the accompanied drawings wherein like reference numerals represent like elements.

[0036] Fig. 1 illustrates a vehicle level architecture comprising an electric fuse according to one embodiment of the invention.

[0037] Fig. 2 illustrates a block diagram of an electric fuse receiving various inputs & providing outputs for effective electrical protection.

[0038] Fig. 3 illustrates internal components of an electric fuse necessary for operation.DETAILED DESCRIPTION:

[0039] The invention along with preferred embodiments will now be described in detail with reference to the accompanying drawings. The preferred embodiment does not limit the scope and ambit of the disclosure. The description provided is purely by way of example and illustration.

[0040] It will be readily understood that components of the present invention, as generally described and illustrated in figures herein, could be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description of the embodiments of the invention as represented in the figures is not intended to limit the scope of the invention but is merely representative of certain examples of presently contemplated embodiments in accordance with the invention. The presently described embodiments will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout.

[0041] Fig.l illustrates an electrical protection system for an automotive vehicle. The protection system comprises of a vehicle power source (10) preferably an auxiliary battery of 12V. There are a plurality of electrical loads (30) connected to the vehicle power source (10). A main power source (40) is connected to the vehicle power source (10). The electrical loads (30) comprise of lighting loads (30), switching inputs to a motor control unit (MCU), inputs to ignition activation, or to a telematics unit. A circuit breaker (20) preferably a fuse (20) is used for connecting or disconnecting the vehicle power source (10) to the main power source (40) and the electrical loads (30). According to an embodiment, the fuse (20) is preferably an electric operated fuse (20) comprising semiconductor devices including MOSFET, IGBT or thyristors (SCRs) performing connection or disconnection, ensuring safety during overcurrent or overvoltage condition. The circuit breaker (20) has a threshold determination unit (100) to detect overcurrent or overvoltage and autonomously performs theconnection or disconnection, ensuring safety during overcurrent or overvoltage condition. The fuse (20) communicates with at-least one control unit; wherein the fuse (20) continuously monitors a load current and charging current and provides feedback to the control unit (50) to assess the fault. According to an embodiment, the control unit (50) is a vehicle control unit (VCU) for managing and coordinating the operation of multiple systems, including the powertrain, battery management system (BMS), braking, and thermal management. The control unit (50) actuates the circuit breaker (20) upon detecting the current or voltage exceeding a predefined threshold limit and time in both vehicle operative and inoperative states. The vehicle operative states include power and energy states, motion and drive states, location and connectivity states, user interaction states, system and diagnostic states. The power and energy states define how the vehicle manages, stores, and consumes electrical power. The motion and drive states represent the vehicle’s movement status and drivetrain activity. The location and connectivity states indicate the vehicle’s position and communication with external networks. The user Interaction States captures how the driver or passengers engage with vehicle controls and interfaces. The system and diagnostic states reflect the health, faults, and internal monitoring of vehicle systems.

[0042] The control unit commands the fuse (20) to disconnect the vehicle power source (10) supply from the main power supply source and load after a predetermined time on detection that the overcurrent has crossed a predetermined threshold. According to an embodiment, the control unit (50) has an adjustment unit dynamically regulating the threshold level of current or voltage in response to varying load demands from the electric loads (30), optimizing system performance and safety.

[0043] The protection system for automobiles ensures robust health monitoring of the vehicle power source (10) during charging phases. A sensing unit of the fuse (20) is configured to monitor the charging current of the vehicle power source (10) from the main power source (40) and may communicate with control unit (50) for further actions like to disconnect charging based on charging state of the vehicle power source (10). The invention pertains to detect unintended current flow to the loads (30) and record it in the vehicle control unit (50). This leads to information of the event recorded for the service personnel to analyzethe event. Based on the vehicle state, an appropriate action to cut off the supply to the load is taken. The vehicle state includes ignition input, load current sensing, charging.

[0044] Fig. 2 illustrates a block diagram of an electric fuse (20) receiving various inputs & providing outputs for effective electrical protection. The electric fuse (20) connects or disconnects the vehicle power source (10) to the electrical loads (30) and the main power source (40). There is a trigger input from the vehicle control unit (VCU) (50) to the electric fuse (20), which is used to cut off the supply to the loads (30) and the vehicle power supply, that the vehicle control unit (50) decides based on control strategy during overcurrent or overvoltage condition beyond a predetermined threshold value. A reset input is provided to the electric fuse (20) to proceed with the normal function of the protection system of the vehicle. This is used for closing the switch. It overrides any trigger to open the switch, whether it is internal based on the limits set inside the fuse (20) by the threshold determination unit (100) or externally from vehicle control unit (50) based on the control strategy. The electric fuse (20) status is also communicated to the VCU (50) and based on that action is taken by the VCU (50) for operation of the fuse (20). The power output is relayed through the electric fuse (20) to the vehicle load. A signal corresponding to the current flowing through the switch is communicated to the vehicle control unit (50). There is another wake up signal to the VCU (50) from the fuse (20), which activates it from sleep in vehicle OFF condition in case of overcurrent or overvoltage event.

[0045] According to Fig. 3, the internal component of an electric fuse (20) has been depicted. The electric fuse (20) comprises of delay & latch circuit (200), which receives input from the VCU (50), the delay and latch circuit (200) to delay and hold signal for a set time, and the output state respectively until reset for driving at-least one FET drive circuit (250) operating the semiconductor switches. There is further a threshold determination unit (100) paired to the delay & latch circuit (200) for detection and comparison of current and voltage values basis a threshold value & threshold time that results in triggering of the switches. The threshold determination unit (100) detects overcurrent or overvoltage for a predetermined time to operate the fuse (20) for disconnection or connection post correction of the condition. Along with the threshold determination unit (100), the control unit has an adjustment unit, which dynamically regulates the threshold level of current or voltage in response to varyingload demands from electric loads (30), power demands for the vehicle power source (10) optimizing system performance and safety. The threshold overcurrent and predetermined time for disconnection or connection is configured based on the vehicle state and the direction of the current flow. The fuse (20) has a load current sensing unit for load current sensing. The sensing circuit takes input from the resistor (a shunt resistor). The fuse (20) wakes up the control unit during vehicle off condition in an overcurrent or overvoltage condition; wherein the control unit (50) assess the reason for vehicle wakeup. The control unit (50) identifies the wake-up reason and assesses the load current and associated fault. The fuse (20) has a dynamic adjustment of over-current thresholds in response to varying user demands, optimizing system performance and safety. The protection system has a reset pin overriding any self-trigger or triggers from the control unit. This helps in rider safety so that fuse (20) doesn’t trigger in case of any event during drive.

[0046] The operation of the fuse (20) can be detailed as follows during vehicle ON & OFF condition. When vehicle is OFF, the fuse unit continuously monitors the current flowing through the switches. It wakes up the VCU (50), in case the current is above the threshold level. The VCU (50) wakes up and records the current value, post which the VCU (50) triggers the fuse (20) to switch OFF based on control strategy implemented. If VCU (50) doesn’t trigger the fuse (20) within the defined threshold time, the fuse (20) will self-trigger the switch OFF based on the threshold determination unit (100). When vehicle is ON, since start-up, the VCU (50) holds the reset pin high to avoid any interruption in the supply to the load. The VCU (50) monitors the current flowing through the switch (analog voltage input from e-Fuse (20) unit to VCU) (50). In case of any over current, the VCU (50) records this event and triggers the switch based on the control strategy.

[0047] The proposed protection system offers multiple operational and safety advantages for electric vehicle applications. It effectively limits overcurrent flowing from the battery to the load, thereby preventing damage to critical components. The inclusion of a reusable fuse mechanism not only enhances protection but also reduces maintenance costs and downtime compared to conventional single-use fuses. The system further prevents unnecessary drainage of the battery pack, improving overall energy efficiency and extending vehiclerange. By dynamically adjusting the fuse’s threshold current based on real-time vehicle load conditions, the invention ensures optimized performance under varying operating scenarios.

[0048] The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The embodiments described are to be considered in respects as illustrative and not restrictive.

[0049] Within this patent specification, it is crucial to acknowledge the versatility and potential variations of the invention. Other embodiments may incorporate a variety of component units, logical units, and switching units to achieve similar or modified functionalities. These embodiments may involve different arrangements, configurations, or combinations of these units, depending on specific application requirements or design preferences. The scope of the invention encompasses such alternative embodiments, wherein the essential features and principles remain applicable, albeit with potential modifications to suit particular contexts or objectives. Thus, while the embodiments described herein serve as examples, it is understood that numerous other configurations and arrangements are feasible and fall within the scope of the invention as defined by the claims.Reference Numerals:-10 - vehicle power source20 - circuit breaker / Fuse30 - loads40- main power source50 - VCU / vehicle control unit100 - Threshold determination unit200 - delay & latch circuit250 - FET drive circuit

Claims

We Claim: -1. A protection system for vehicle, comprising: at least one vehicle power source (10) for driving the vehicle; a plurality of electrical loads (30) connected to the vehicle power source (10); at least one main power source (40) connected to the vehicle power source (10); at least one circuit breaker (20) for connecting or disconnecting the vehicle power source (10) to the electrical loads (30) and the main power source (40); a control unit (50) in communication with the circuit breaker (20); wherein the control unit (50) is configured to detect the current or voltage supplied between the vehicle power source (10), main power source (40) and the electrical loads (30) and actuate the circuit breaker (20) upon detecting the current or voltage exceeding a predefined threshold limit and time in both vehicle operative and inoperative states.

2. The protection system for vehicle, as claimed in claim 1 , wherein the threshold limit of the current and voltage, and a predetermined time for disconnection or connection of the circuit breaker (20) is configured based on the vehicle operative and inoperative states and the direction of the current flow to or from the vehicle power source (10).

3. The protection system for vehicle, as claimed in claim 1, wherein the control unit (50) comprises an adjustment unit configured to dynamically regulate the threshold limit of the current or voltage in response to varying power demands for the vehicle power source (10) and the electric loads (30) based on vehicle operative and inoperative states.

4. The protection system for vehicle, as claimed in claim 1, wherein the vehicle operative states include power and energy states, motion and drive states, location and connectivity states, user interaction states, system and diagnostic states.

5. The protection system for vehicle, as claimed in claim 1, wherein the circuit breaker (20) is in the form of a switch, a fuse, or an electronically operated fuse comprising semiconductor devices including MOSFETs, IGBTs or thyristors (SCRs).

6. The protection system for vehicle, as claimed in claim 1 , wherein the circuit breaker (20) is provided with a threshold determination unit (100), which detects current or voltage exceeding the threshold level for a predetermined time and is configured to operate the circuit breaker (20) for disconnection or connection post correction of the condition.

7. The protection system for vehicle, as claimed in claim 6, wherein the circuit breaker (20) comprises a delay & latch circuit (200) configured to delay and hold signal for a set time and maintains output state until reset for driving at-least one FET drive circuit (250) operating the semiconductor switches.

8. The protection system for vehicle, as claimed in claim 7, wherein the threshold determination unit (100) and the control unit (50) are operatively connected to the circuit breaker (20).

9. The protection system for vehicle, as claimed in claim 6, wherein the threshold determination unit (100) continuously monitors current and voltage and provides feedback to the control unit (50) for the control unit (50) to assess electrical fault.

10. The protection system for vehicle, as claimed in claim 1 , wherein the circuit breaker (20) is self-triggered during the vehicle inoperative condition in the event that the current or voltage exceeding a predefined threshold limit and time and no signal is received from the control unit (50).

11. The protection system for vehicle, as claimed in claim 1 , wherein the circuit breaker (20) comprises a sensing unit configured to monitor the charging current to the vehicle power source (10) and to communicate with the control unit (50) for further actions including disconnecting charging based on charging state of the vehicle power source (10).

12. The protection system for vehicle, as claimed in claim 1, wherein the circuit breaker (20) includes a reset pin for overriding any self-trigger or triggers from the control unit (50).

13. The protection system for vehicle, as claimed in claim 1, wherein the main power source (40) and the vehicle power source (10) are a traction battery and an auxiliary battery, respectively.

4. The protection system for vehicle, as claimed in claim 1, wherein the control unit (50) is a vehicle control unit (VCU) configured for managing and coordinating the operation of multiple systems, including the powertrain, battery management system (BMS), braking, and thermal management.

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