TECHNICAL FIELD:
[001] The present subject matter described herein, relates to the battery systems, in particularly to improve safety in hybrid or electric vehicles having multiple battery system, for example, at least one 12V lead acid battery and at least one Li-ion battery. The present subject matter, in particular, relates to a system and a method to prevent serious/severe hazards in event of non-recoverable fault triggers in battery pack of the hybrid or electric vehicle.
BACKGROUND OF THE INVENTION:
[002] Background description includes information that may be useful in understanding the present invention.
[003] All the Hybrid or electric vehicles may have two types of batteries, one is primary battery and the other is secondary battery. The primary battery is basically a Lead-Acid battery that is also used in the conventional gasoline vehicles and the secondary battery is Lithium-ion (Li ion) battery. The lead-acid battery may supply power to auxiliary loads, such as head lamp, blower fan, and music system. The secondary battery, i.e., Li-ion battery may be used for traction of vehicle and/or to supply power to auxiliary loads. The Lead-acid battery supplies power to all the controllers inside the vehicle like a vehicle control unit (VCU), and/or a body control module (BCM) and usage of the secondary battery depends upon the level of hybridization in the hybrid or the electric vehicles. The primary battery and the secondary battery may of same voltage, i.e., low voltage (LV). In another scenario, the secondary battery may be of different voltage including high voltage (HV) and whereas the primary battery is of low voltage (LV).
[004] Technical problem: When a non-recoverable fault triggers in the battery pack of the hybrid or electric vehicle it causes permanent failure in battery life. The battery becomes useless due to the non-recoverable fault, for an example, if there is ingress of water in the battery, then severe hazards can occur like abnormality in battery temperature, hardware fault in the BMS, and release of flammable gases resultantly fire in the vehicle. Therefore, at the event of non-recoverable fault, it is required to discharge the Li-ion battery immediately prevent severe hazard, for example, fire hazard due to release of flammable gases, such as hydrogen and oxygen gas.
[005] Some of the existing technologies to prevent severe hazards due to battery system failure available are given below.
[006] In a prior art, US20110127945, titled “Forced discharge mechanism and safety switch device for storage battery”, a battery module is provided with the forced discharge mechanism for the storage battery. The forced discharge mechanism allows the electric resistor to come in contact with a pair of terminals from the power transport paths following ingress of the water L, thereby establishing conduction between both the power transport paths. The forced discharge mechanism is provided with a float portion that receives the buoyant force of the water, discharge paths for establishing conduction between both the power transport paths, and a guide portion that guides the float portion. This solution is applicable for outdoor storage batteries like solar farm, it is not applicable for hybrid or electric vehicles where battery is generally mounted inside the vehicle cabin. In this solution, battery can be re-used however, in hybrid or electric vehicle upon occurrence of non-recoverable fault trigger, Li-ion battery cannot be re-used.
[007] Existing solutions either not discharging the battery in non-recoverable faults or discharging it with electrolytic solutions which releases flammable gases which could trigger fire related safety hazards. Hence, carried out in controlled environment. Further, replacing the battery without discharging it again is a safety hazard as it can catch fire due to release of flammable gases from electrolytic solution.
[008] Therefore, there is a need of a system and method to discharge Li-ion battery completely when non-recoverable faults are trigged in battery and the battery is no more usable.
[009] The information disclosed in this background of the subject matter section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.
OBJECTS OF THE INVENTION:
[0010] Some of the objects of the present disclosure, which at least one embodiment herein satisfy, are listed herein below.
[0011] It is therefore an object of the present subject matter to overcome the aforementioned and other drawbacks in the solutions available in state-of-the-art.
[0012] The principal objective of the present subject matter is to provide a system and a method for safety improvement in hybrid or electric vehicles when a non-recoverable fault triggers in a secondary battery, i.e., Lithium-ion battery.
[0013] Another object of the present subject matter is to provide a system and a method to fully discharge the secondary battery in case non-recoverable fault triggers in battery to prevent fire hazard due to electrolytic process in the battery and release of flammable gases.
[0014] Another object of the present subject matter is to provide a system and a method to discharge the leftover energy of the battery to prevent further hazards.
[0015] One another object of the present subject matter is to provide a system and a method to prevent fire hazard using emergency discharge system provided in the secondary battery when battery management system is not able to establish communication with a vehicle control unit.
[0016] These and other objects and advantages of the present subject matter will be apparent to a person skilled in the art after consideration of the following detailed description taken into consideration with accompanying drawings in which preferred embodiments of the present subject matter are illustrated.

SUMMARY OF THE INVENTION:
[0017] Solution to one or more drawbacks of existing technology, and additional advantages are provided through the present subject matter. Additional features and advantages are realized through the technicalities of the present subject matter. Other embodiments and aspects of the subject matter are described in detail herein and are considered to be a part of the claimed subject matter.
[0018] The present invention discloses a system and method to prevent the severe hazards in case of non-recoverable fault triggers in the Li ion battery of the Hybrid or electric vehicle. The present invention provides a system and a method to fully discharge the secondary battery in case non-recoverable fault triggers in battery pack (e.g. water ingresses into battery pack, it is not usable anymore due to safety concerns) to prevent the fire hazard due to release of flammable gases and improving safety. When Li ion battery used in Hybrid or electric vehicles without protection from non-recoverable faults, it may cause severe issues due to production of hydrogen and oxygen in the submerged battery (in case of water ingress) which are most likely to result into the critical safety hazards like fire etc.
[0019] In an embodiment, the present subject matter relates to a system to prevent severe hazards due to battery system failure in hybrids or electric vehicles. The system comprising a primary battery, at least one secondary battery connected to the primary battery along with vehicle control unit (VCU) and body control module (BCM). Each of the at least one secondary battery comprising a cell stack having a combination of a plurality of cells, a two level water detection sensor positioned at bottom of the cell stack to generate level one alerting signal upon detecting first water level (L1); a battery management system (BMS) configured to receive the level one alerting signal from the sensor. The vehicle control unit (VCU) is communicatively coupled with the battery management system (BMS) of the secondary battery through communication control lines to receive the level one alerting signal. The body control module (BCM) is communicatively coupled with the VCU via the communication control lines, to receive the level one alerting signal from the VCU to initiate discharge process of the secondary battery. The BCM establishes upon receipt of the level one alerting signal, connection between the secondary battery and a plurality of auxiliary loads to discharge the secondary battery.
[0020] The BCM establishes connection between the secondary battery and a plurality of auxiliary loads to discharge the secondary battery by closing switch S2.
[0021] The BCM establishes connection between the secondary battery and a plurality of auxiliary loads to discharge the secondary battery by closing switch S3.
[0022] In an aspect, the BCM opens switch (S1), upon receipt of the level alerting signal, to disconnect connection between the plurality of auxiliary loads and the primary battery.
[0023] In an aspect, the secondary battery comprises an emergency discharge circuit (EDC) is configured to receive level two alerting signal from the two level water detection sensor upon detecting second water level (L2) in the cell pack to initiate discharge process of the secondary battery. The emergency discharge circuit (EDC) closes switch (S3), upon receipt of the two level alerting signal, to establish connection between the secondary battery and a high power load from the plurality of auxiliary loads to discharge the secondary battery.
[0024] In an aspect, the emergency discharge circuit (EDC) closes switch (S3) to establish connection between the secondary battery and a high power load to discharge the secondary battery when the secondary battery is not in communication with the VCU.
[0025] In an aspect, the emergency discharge circuit (EDC) comprises a pair of diodes (D1, D2) at input voltage to pass maximum voltage either from the primary battery or from the secondary battery through one of the diode from the pair of diodes (D1, D2); a Metal–Oxide–Semiconductor Field-Effect Transistor (MOSFET) (S4) receives the maximum input voltage at drain terminal; and a latching relay (LR) (which is also switch (S3)) to get closed upon receiving input voltage at gate terminal of the MOSFET (S4) after water detection and establish connection between the secondary battery and the high power load to discharge the secondary battery.
[0026] In an aspect, the latching relay (LR) (or the switch (S3)) is communicatively coupled with the BMS. The BMS can override the switch (S3).
[0027] In an aspect, the primary battery is preferably a Lead- Acid battery and the at least one secondary battery is preferably a Li-ion battery.
[0028] In an aspect, the system further comprises a DC-DC converter provided in between the primary battery and the at least one secondary battery to maintain both the primary battery and the at least one secondary battery at optimum charge levels.
[0029] In an aspect, the high power load is preferably a heater or Air conditioner.
[0030] In another embodiment, the present subject matter discloses a method to prevent severe hazards due to battery system failure in hybrids or electric vehicles. The method comprising detecting, by a two level water sensor positioned in secondary battery, ingress of water level; determining, whether ignition system is in ON state or OFF state, when ignition system is in OFF state, sending, by battery management system of the secondary battery, water level alerting signal to wake up a vehicle control unit; sending, by the VCU, the water level alerting signal to Body Control Module to wake up the BCM; determining, by the BCM, whether all control lines communicates with a plurality of auxiliary loads; connecting, by opening switch (S1) and closing switch (S2), the secondary battery with the plurality of auxiliary loads; discharging the secondary battery through the connected the plurality of auxiliary loads to prevent hazard in the secondary battery.
[0031] In an aspect, the method step further comprise connecting, by opening switch (S1) and closing switch (S3), the secondary battery with the plurality of auxiliary loads.
[0032] In an aspect, the method step determining, further comprises when the ignition system is in ON state indicating communication between the secondary battery via the BMS with the VCU and the BCM: determining, by the BCM, whether all control lines communicates with a plurality of auxiliary loads; connecting, by opening switch (S1) and closing switch (S2) or switch (S3), the secondary battery with the plurality of auxiliary loads; discharging the secondary battery through the connected the plurality of auxiliary loads to prevent hazard in the secondary battery.
[0033] In an aspect, the method step the determining further comprises: when the VCU is not communicating with the BMS of the secondary battery, the method comprises: activating an Emergency Discharge Circuit (EDC); closing, upon activation of the EDC, the switch (S3) where the switch (S1 and S2) remain in default state to establish connection between the secondary battery with a high power load from the plurality of auxiliary loads; and discharging, by the high power load, the secondary battery to prevent hazards.
[0034] In an aspect, the method step activating the emergency discharge circuit (EDC) comprises: receiving maximum input voltage either from the primary battery or from the secondary battery through one of the diode from a pair of diodes (D1, D2); receiving the maximum input voltage at a Metal–Oxide–Semiconductor Field-Effect Transistor (MOSFET) (S4) at drain terminal; closing the switch (S3) (latching relay (LR))upon receiving input voltage at gate terminal of the MOSFET (S4) due to water detection; establishing connection between the secondary battery and the high power load to discharge the secondary battery.
[0035] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS:
[0036] It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments. The detailed description is described with reference to the accompanying figures. In the figures, a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system or methods or structure in accordance with embodiments of the present subject matter are now described, by way of example, and with reference to the accompanying figures, in which:
[0037] Fig. 1 illustrates a block diagram hybrid or electric vehicle having Vehicle Control Unit (VCU), Body Control Module, (BCM), primary and secondary battery along with auxiliary loads connected with the primary and secondary battery through power transmission lines and connected with the BCM through the control lines, in accordance with an embodiment of the present disclosure;
[0038] Fig. 2 illustrates a block diagram of the hybrid or electric vehicle system in case of non-recoverable fault triggers in battery pack when the secondary battery is on higher voltage as compared to the primary voltage, in accordance with an embodiment of the present disclosure;
[0039] Fig. 3 illustrates a block diagram of the secondary battery of Fig. 1 and Fig. 2, in accordance with an embodiment of the present disclosure;
[0040] Fig. 4 illustrates a circuit diagram of the emergency discharge circuit as shown in fig. 3, in accordance with an embodiment of the present disclosure;
[0041] Fig. 5 represents a flow chart of the process illustrating the various steps performed by the multiple controllers inside the vehicle to discharge leftover energy in the second battery, in accordance with an embodiment of the present disclosure.
[0042] The figures depict embodiments of the present subject matter for the purposes of illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the subject matter described herein.
DETAILED DESCRIPTION OF THE INVENTION:
[0043] The detailed description of various exemplary embodiments of the disclosure is described herein with reference to the accompanying drawings. It should be noted that the embodiments are described herein in such details as to clearly communicate the disclosure. However, the amount of details provided herein is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the present disclosure as defined by the appended claims.
[0044] It is also to be understood that various arrangements may be devised that, although not explicitly described or shown herein, embody the principles of the present disclosure. Moreover, all statements herein reciting principles, aspects, and embodiments of the present disclosure, as well as specific examples, are intended to encompass equivalents thereof.
[0045] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a",” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes” and/or “including,” when used herein, specify the presence of stated features, integers, steps, operations, elements and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or groups thereof.
[0046] It should also be noted that in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may, in fact, be executed concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved.
[0047] In addition, the descriptions of "first", "second", “third”, and the like in the present invention are used for the purpose of description only, and are not to be construed as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Thus, features defining "first" and "second" may include at least one of the features, either explicitly or implicitly.
[0048] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms, e.g., those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
[0049] The present invention discloses a system and a method to prevent severe hazards due to battery system failure in hybrids or electric vehicles. The present invention proposes to fully discharge the secondary battery in case non-recoverable fault triggers in battery pack (e.g. after water ingresses into battery pack, it is not usable anymore due to safety concerns) to prevent the fire hazard due release of flammable gases and improving safety.
[0050] In the present subject matter relates to prevention of severe hazards due to battery system failure in hybrids or electric vehicles in an event of non-recoverable fault, such as ingress of water inside the Li-ion battery. The present subject matter provides a system and a method to discharge the Li-ion battery upon detection of the non-recoverable fault in the Li-ion battery. When the non-recoverable fault is detected in the battery then it triggers alerting alarms and a vehicle control unit (VCU) takes the decision that the battery is no more usable to the vehicle and it discharges the Li ion battery through auxiliary loads like head lamp, electric heaters, etc. It does not discharge the Lead-acid battery so that when vehicle is cranked, the Lead-acid battery starts the vehicle.
[0051] Non-limiting Definitions
[0052] In the disclosure hereinafter, one or more terms are used to describe various aspects of the present disclosure. For a better understanding of the present disclosure, a few definitions are provided herein for better understanding of the present disclosure.
[0053] Battery Management System (BMS): A system which is any electronic system with electronic circuitry that manages a rechargeable battery (cell or battery pack), such as by protecting the battery from operating outside its safe operating area, monitoring its state, calculating secondary data, reporting that data, controlling its environment, authenticating it and / or balancing it. The system manages a plurality of cells in a battery module such as by detecting state of health (SOH), temperature, state of charge (SOC) condition, over-charge and over-discharge voltage conditions, and communicating the conditions of the plurality of cells. The system may be micro-controller based system.
[0054] Non-recoverable fault: Ingress of water in the battery pack or cell pack.
[0055] Low voltage: Less than 60V
[0056] High voltage: 60V or more
[0057] MOSFET: A metal–oxide–semiconductor field-effect transistor is a field-effect transistor (FET with an insulated gate) where the voltage determines the conductivity of the device. It is used for switching or amplifying signals. The ability to change conductivity with the amount of applied voltage can be used for amplifying or switching electronic signals. The MOSFET has four terminals, source (S), gate (G), drain (D) and body (B) terminals.
[0058] Vehicle Control Unit: It is electronic control circuitry based on micro-controller to control operations and health of the Li-ion battery.
[0059] Body Control Module: It is electronic control circuitry based on micro-controller to control operations, such as control of auxiliary loads like blower, headlamp, heater, Air Conditioner, central locking, vehicle cabin lamp, wipers and other electrical loads on body of the vehicle.
[0060] The all modules and control unit are well known to a person skilled in the art. Therefore, only brief introduction has been provided to define function of the modules and component.
[0061] In the present invention there are described two scenarios on the basis of the working condition of all the controllers inside the vehicle. Both the scenarios are explained below.
[0062] Structure and layout of the system
[0063] Referring to Figure 1, illustrating block diagram of hybrid or electrical vehicle having a system 100 to prevent severe hazards due to battery system failure. As shown, the system 100 comprises a primary battery 104 and at least one secondary battery 109. There can be a plurality of secondary battery in the system 100 however, to explain the present subject matter single secondary battery 109 is considered. The present subject matter can be applicable to any system having a plurality of primary battery and a plurality of secondary battery. The system 100 further comprises a vehicle control unit (VCU) 105 that is provided to monitor all the controllers, such as Body control module (BCM) 103 inside the vehicle to supply electric power. The body control module (BCM) 103 is provided to control a plurality of auxiliary loads, such as head lamp load 101, blower fan load 102, and high power load, i.e., heater load 108 of the vehicle. The BCM 103 may also control central locking, Air conditioner, vehicle cabin lamp, and infotainment system of the vehicle by supplying required power load. A power electronic module (PEM) 106 consists of a combination of motor and inverter that is used to convert DC voltage of the secondary battery 109 into AC voltage to operate the motor. The plurality of auxiliary loads may take electric energy from the primary battery 104 and/or from the secondary battery 109. The primary battery 104 is Lead Acid battery and the secondary battery 109 is Lithium-ion battery.
[0064] A switch S1 is being provided to isolate the Lead acid battery 104 with the auxiliary loads 101, 102, and 108. Another switch S2 is being provided on main electric supply line 110 in between the auxiliary load, such as head lamp load 101 and blower fan load 102, and the secondary battery 109. The switch S2 isolates the secondary battery 109 from the auxiliary load, such as head lamp load 101 and blower fan load 102 in default state which is open. Yet another switch S3 is provided on the electrical lines in between the high power load 108 and the main electric supply line 110. The switch S3 isolates the high power load 108 with the primary battery 104 and/or with the secondary battery 109 supplying electric power through the main electric supply line 110 in default state which is open. All three switch S1, S2, and S3 are Normally open switches, however, the present inventive concept can be implemented by replacing the normally open switch with normally close switch or any other switch that provides open/close or connection/disconnection mechanism on the electric supply lines.
[0065] The primary battery 104 and the secondary battery 109 are of low voltage. Generally, the primary battery 104 is 12V Lead Acid Battery and the secondary battery 109 is 12VLi-ion battery. Both the primary battery 104 and the secondary battery 109 are low voltage (LV) battery system, however, the present inventive concept can be implemented on the battery system having High voltage (HV) where voltage is >60V.
[0066] Referring to Figure 2, illustrating a block diagram of the system 100 to prevent severe hazards due to battery system failure in hybrid or electric vehicles where the primary battery 104 and the secondary battery are not at the same voltage. To make the system operating with different levels of primary battery and secondary battery voltage, a DC-DC converter 201 is connected in series with the primary battery 104 and the secondary battery 109 to convert the higher voltage (LV or HV, i.e., more than 12V) into the low voltage (LV, i.e., 12V) to maintain sufficient energy in both the batteries 104, 109. Apart from positioning of the DC-DC converter 201 in the system 100, rest of the structure is same as of Fig. 1.
[0067] Referring to Fig. 3 illustrating structure of the secondary battery 109 of Fig. 1 and Fig. 2. The secondary battery 109 is having a cell stack 304 that is basically a series combination of a plurality of Li-ion cell assemblies. The secondary battery 109 further comprises a two level water sensor 303, a battery management system 301, and an emergency discharge circuit (EDC) 302. The battery management system 301 is communicatively coupled with the plurality of Li-ion cells to manage and control health of the plurality of cells. The BMS 301 is also responsible for implementing various battery state estimations, such as state of charge (SOC), state of health (SOH), state of function (SOF), state of power (SOP), etc. The BMS 301 is communicatively coupled with the Vehicle Control unit 105 of the vehicle which controls and manage the requirement of vehicle and the secondary battery 109 vice versa.
[0068] Upon occurrence of any fault in the secondary battery 109, the BMS 301 communicates the same to the VCU 105 for necessary action, such as discharge action. The two level water detection sensor 303 detects water in two levels in the cell stack 304 of the secondary battery 109. Upon detection of level one water ingress in the cell stack, the two level water detection sensor 303 sends level one alerting signal to the BMS 301 and the BMS 301 sends the level one alerting signal 111 to the VCU 105. The BMS 301 senses the two level water detection sensor 303 to ensure the battery operation in safe zone.
[0069] The emergency discharge circuit (EDC) 302 (as shown in Fig. 4) is electrical-electronic circuit to drive a latching relay 408 to close the normally open switch S3 or to open the normally close switch S3. The emergency discharge circuit (EDC) 302 is communicatively coupled with the BMS 301 and the two level water detection sensor 303.
[0070] The emergency discharge circuit (EDC) 302 helps in two condition firstly when level two alerting signal is being generated by the two level water detection sensor 303 and secondly when there is no communication in between the VCU 105 and the BMS 301. Alternatively, in any condition, when the BMS 301 is unable to wake-up the VCU 105.
[0071] The emergency discharge circuit 302 comprises a latching relay 408 which closes the switch S3 to connect the secondary battery 109 with the high power load 108. The Switch S3 is also controlled by the BMS 301 that can open and close the switch using the latching relay 408. The latching relay 408 is a two-position electrically-actuated switch. It is controlled by two momentary-acting switches or sensors, one that 'sets' the relay, and the other 'resets' the relay. The emergency discharge circuit 302 can only set the latching relay 408. It sets (ON) or resets (OFF) by the input of a pulse voltage. The emergency discharge circuit 302 comprises two diodes D1 and D2 that are connected to Lead-Acid battery 104 power supply line and the secondary battery 109 power supply line, respectively. In this circuit, D1 become forward bias if Lead-Acid battery 104 power supply is more than the secondary battery 109 supply and D2 become forward bias if the secondary battery 109 power supply is more than the Lead- Acid battery 104 power supply. When the water reaches to level 2, a pseudo resistance is generated between sensor 303 GND, level 1 and level 2 terminal by electrolytic water which contains salts. The value of resistance depends on spacing between the terminals and electrical conductivity of water. The pseudo resistance between level 1 and level 2 terminal of the two level water detection sensor 303 lies in parallel with resistance R1 of EDC circuit in such a way that equivalent resistance (lets say R1eq) is always less than R1. Similarly, the pseudo resistance between GND and level 2 terminal of the two level water detection sensor 303 lies in parallel with zener diode ZD2 (lets say RZD2 eq). So, once the current start flowing from D1 or D2 to R1eq and RZD2 eq through C1 (C1 is a storage type capacitor), voltage drop across RZD2 eq is sufficient to drive the switch S4 which further drive the latching relay 408. ZD1 and ZD2 are used to regulate the input drive voltage of latching relay 408 and switch S4 respectively. After sometime, current stop flowing as C1 is fully charged and having same voltage as input voltage. Then, S4 is open state. The purpose of C1 and C2 is to drive the latching relay 408 for couple of seconds to position it in set (ON) or reset (OFF) to close the switch S3. In this way EDC is activates and consumes power from either supply for short duration to avoid the discharge of lead acid battery which is required to crank the vehicle. The components in circuit are reduced to minimize the complexity of circuit and to easily convey the functionality.
Condition 1: when the control boards, such as VCU, BCM are in communication with the BMS of the secondary battery
[0072] When the two level water detection sensor 303 detects ingress of water at level one ‘L1’ in the cell stack 304, the two level water detection sensor 303 generates level one alerting signal 111 and sends the generated level one alerting signal 111 to communicatively coupled the BMS 301 of the secondary battery 109. The BMS 301 receives the level one alerting signal 111 from the two level water detection sensor 303 and transmit the level one alerting signal 111 to the vehicle control unit (VCU) 105 through control lines 112. The BCM 103, communicatively coupled with the VCU 105 via control lines 112,113, receives the level one alerting signal 111 from the VCU 105 to initiate discharge process of the secondary battery 109. Upon receipt of the level one alerting signal 111, the BCM 103 closes switch ‘S2’ or switch ‘S3’, to establish connection between the secondary battery 109 and a plurality of auxiliary loads 101, 102, 108 to discharge the secondary battery 109. The BCM 103 either closes the switch ‘S2’ or switch ‘S3’ at a time to establish connection between the secondary battery 109 and a plurality of auxiliary loads 101, 102, 108 to discharge the secondary battery 109. In an aspect, the BCM 103 may close the switch ‘S2’ and switch ‘S3’ at a time to establish connection between the secondary battery 109 and a plurality of auxiliary loads 101, 102, 108 to discharge the secondary battery 109.
[0073] Simultaneously, the BCM 103 opens switch ‘S1’, upon receipt of the alerting signal 111, to disconnect connection between the plurality of auxiliary loads 101, 102, 108 and the primary battery 104 to avoid discharging of the primary battery 104.
[0074] The emergency discharge circuit (EDC) 302 of the secondary battery 109 is configured to receive level two alerting signal 111 from the two level water detection sensor 303 upon detecting second water level ‘L2’ in the cell pack 304 to initiate discharge process of the secondary battery 109. The emergency discharge circuit (EDC) 302 closes switch ‘S3’, upon receipt of the two level alerting signal 111, to establish connection between the secondary battery 109 and a high power load 108 from the plurality of auxiliary loads 101, 102, 108 to discharge the secondary battery 109. The emergency discharge circuit (EDC) 302 does not have any control on the switch ‘S1’ and the switch ‘S2’, therefore, the switch ‘S1’ and the switch 'S2’ remain in default state that may be open state. Therefore, only the high power load 108 is taking power from the secondary battery 109 to discharge the secondary battery 109.
Condition 2: when the control boards, such as VCU, BCM are not communicating with the BMS of the secondary battery
[0075] When the BMS 301 is not in communication with the VCU 105 due to lower voltage of lead acid battery which may not be able to power up the controllers or damage in any of wire harness assembly due to flow of flood water. When there is no communication between the BMS 301 and the VCU 105, the BMS 301 is not able to send the level one alerting signal 111 to the VCU 105 for closing the switch ‘S2’ and/or the switch ‘S3’. In the present condition, the two level water detection sensor 303 activates the emergency discharge circuit (EDC) 302 which closes switch ‘S3’ to establish connection between the secondary battery 109 and a high power load 108 to discharge the secondary battery 109 when the secondary battery 109.
[0076] In an embodiment, water sensor is a part of EDC or physically connected to EDC, it does not need to communicate to the EDC. The alerting signal is based on level 1 is generated for the BMS and the VCU, so that VCU can take necessary action.
[0077] The emergency discharge circuit (EDC) 302 comprises a pair of diodes (D1, D2) at input voltage to receives maximum voltage either from the primary battery 104 or from the secondary battery 109 through one of the diode from the pair of diodes D1, D2. Further the received input voltage is given to a Metal–Oxide–Semiconductor Field-Effect Transistor (MOSFET) ‘S4’ for conducting the latching relay 408 which closes the switch ‘S3’. The latching relay (LR) 408 to close the switch ‘S3 upon receiving input voltage from the MOSFET ‘S4’ and establish connection between the secondary battery 109 and the high power load 108 to discharge the secondary battery 109.
[0078] The EDC 302 draws current from source, i.e., the primary battery 104 or the secondary battery 109 which is having maximum input voltage which is managed by diode D1 and D2. Initially, the voltage at input drive of MOSFET ‘S4’ is sufficient to drive the MOSFET ‘S4’ which would close the Latching Relay 408. After couple of seconds, the capacitor C1 will be charged hence reducing the voltage at input drive of the MOSFET S4 which would open the latching relay 408. Even if the MOSFET S4 is close for long time, the second capacitor C2 will be charged equal to source voltage, hence no power consumption from source as the input drive of latching relay 408 will be OFF.
[0079] In an embodiment, the BMS 301 is communicatively coupled with latching relay (LR) 408 to control operation of the switch S3. The BMS 301 may open or close the switch ‘S3’ depending on the battery state of charge (SOC) however, the EDC 302 can only close the switch S3.
[0080] In an embodiment, a DC-DC converter 201 provided in between the primary battery 104 and the secondary battery 109 to transfer power between both the primary battery 104 and the secondary battery 109.
[0081] In an embodiment, the high power load 108 is preferably a heater or Air conditioner.
[0082] Fig. 5 illustrates a method 500 for prevent severe hazard due to battery system failure in hybrid or electrical vehicles. The method comprising:
[0083] At step 501, the method 500 includes detecting ingress of water level in the secondary battery by a two level water sensor 303 which is positioned in the secondary battery 109. Based on the water level inside the cell stack of the secondary battery, the two level water sensor 303 generates two alerting signal one indicating the ingress of water upto level one ‘L1’ and another signal indicates ingress of water upto level two ‘L2’. The two level water sensor 303 sends the generated signal to the BMS 301 and the VCU 109. Once both the signals are detected, EDC will activate.
[0084] At step 502, the method includes determining whether ignition system is in ON state or OFF state. When ignition system is in OFF state, the method proceeds to step 503. When the ignition system is in ON state, the method proceeds to step 505.
[0085] At step 503, when the ignition system is OFF, the method includes sending, by battery management system 301 of the secondary battery 104, generated water level alerting signal 111 to a vehicle control unit 105 to wake up the VCU 105 to take necessary action.
[0086] At step 504, the method includes sending, by the VCU 105, the water level alerting signal to Body Control Module 103 to wake up the BCM 103 to take necessary action.
[0087] At step 505, the method includes determining, by the BCM 103, whether all control lines or communication lines or command lines 112, 113, 114 which can be of Controller Area Network (CAN) bus communication to communicate with a plurality of auxiliary loads 101, 102 and 108 and corresponding switches S1, S2, S3.
[0088] At step 506, the method includes connecting, by opening switch ‘S1’ and closing either switch ‘S2’ or switch ‘S3’, the secondary battery 109 with the plurality of auxiliary loads 101, 102 and 108.
[0089] At step 507, the method includes discharging 507 the secondary battery 109 through the connected the plurality of auxiliary loads 101, 102 and 108 to prevent hazard in the secondary battery 109 due to ingress of water which makes the secondary battery non-usable.
[0090] When the ignition system is in ON state indicating communication between the secondary battery 109 via the BMS 301 with the VCU 105 and the BCM 103 and there is no need to send the wakeup signals to the VCU 105, and the BCM 103, the method proceeds with the steps 505 to 507.
[0091] At the step 505 which determines whether the VCU 105 is not communication with the BMS 301 of the secondary battery 109 which could be due to lower voltage of lead acid battery or damage to wire assembly due to flow of flood water
[0092] At step 508, the method includes activating 508 an Emergency Discharge Circuit (EDC) 302 by receiving both alerting signal from the two level water sensor 303.
[0093] At step 509, the method includes closing 509, upon activation of the EDC 302, the switch ‘S3’ where the switch ‘S1’ and ‘S2’ remain in default state to establish connection between the secondary battery 109 with a high power load 108 from the plurality of auxiliary loads 101, 102 and 108.
[0094] At step 510, the method includes discharging, by the high power load 108, the secondary battery 109 to prevent severe hazards due to water ingress in the secondary battery 109 and electrolytic process due to energy left in the secondary battery.
[0095] The step 508 of the method describing activating the emergency discharge circuit (EDC) 302 further comprises receiving maximum input voltage either from the primary battery 104 or from the secondary battery 109 through one of the diode from a pair of diodes (D1, D2). A Metal–Oxide–Semiconductor Field-Effect Transistor (MOSFET) S4 receives the maximum input voltage to drive the MOSFET S4. The MOSFET S4 drives or conducts a latching relay (LR) 408 to close the switch ‘S3’. Upon closing the switch ‘S3’, the switch ‘S3’ establishes a connection between the secondary battery 109 and the high power load 108 to discharge the secondary battery 109.
[0096] The advantages of the present invention are given below.
1. The present invention does not discharge primary battery so that when cranked it starts the vehicle.
2. The present invention prevents fire hazard using emergency discharge system when all the controllers inside the vehicle are not in working condition.
3. The present invention provides a cost effective method to prevent severe hazards in case of battery system failure.
[0097] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.”
[0098] It will be further appreciated that functions or structures of a plurality of components or steps may be combined into a single component or step, or the functions or structures of one-step or component may be split among plural steps or components. The present invention contemplates all of these combinations. Unless stated otherwise, dimensions and geometries of the various structures depicted herein are not intended to be restrictive of the invention, and other dimensions or geometries are possible. In addition, while a feature of the present invention may have been described in the context of only one of the illustrated embodiments, such feature may be combined with one or more other features of other embodiments, for any given application. It will also be appreciated from the above that the fabrication of the unique structures herein and the operation thereof also constitute methods in accordance with the present invention. The present invention also encompasses intermediate and end products resulting from the practice of the methods herein. The use of “comprising” or “including” also contemplates embodiments that “consist essentially of” or “consist of” the recited feature.

We claim:

1. A system (100) to prevent severe hazards due to battery system failure in hybrids or electric vehicles, the system comprising:
a primary battery (104);
at least one secondary battery (109) connected to the primary battery (104), each of the at least one secondary battery (109) comprising:
a cell stack (304) having a combination of a plurality of cells;
a two level water detection sensor (303) positioned at bottom of the cell stack (304) to generate level one alerting signal (111) upon detecting first water level (L1);
a body management system (BMS) (301) configured to receive the level one alerting signal (111) from the two level water detection sensor (303);
a vehicle control unit (VCU) (105) communicatively coupled with the body management system (BMS) (301) of the secondary battery (109) through control lines (112) to receive the level one alerting signal (111);
a body control module (BCM) (103), communicatively coupled with the VCU (105) via control lines (113), to receive the level one alerting signal (111) from the VCU (105) to initiate discharge process of the secondary battery (109), the BCM (103):
establishes, upon receipt of the level one alerting signal (111), connection between the secondary battery (109) and a plurality of auxiliary loads (101, 102, 108) to discharge the secondary battery (109).

2. The system (100) as claimed in claim 1, wherein the BCM (103) established the connection between the secondary battery (109) and the plurality of auxiliary loads (101, 102) by closing switch (S2).
3. The system (100) as claimed in claim 1, wherein the BCM (103) established the connection between the secondary battery (109) and the plurality of auxiliary loads (101, 102, 108) by closing switch (S2) and Switch (S3).

4. The system (100) as claimed in claim 1, wherein the BCM (103) opens switch (S1), upon receipt of the alerting signal (111), to disconnect connection between the plurality of auxiliary loads (101, 102, 108) and the primary battery (104).
5. The system (100) as claimed in claim 1, wherein the secondary battery (109) comprises an emergency discharge circuit (EDC) (302) configured to receive level two alerting signal (111) from the two level water detection sensor (303) upon detecting second water level (L2) in the cell stack (304) to initiate discharge process of the secondary battery (109), the emergency discharge circuit (EDC) (302):
closes switch (S3), upon detection of two level of water sensor (303), to establish connection between the secondary battery (109) and a high power load (108) from the plurality of auxiliary loads (101, 102, 108) to discharge the secondary battery (109).

6. The system (100) as claimed in claim 5, wherein the emergency discharge circuit (EDC) (302) closes switch (S3) to establish connection between the secondary battery (109) and a high power load (108) to discharge the secondary battery (109) when the secondary battery (109) is not in communication with the VCU (105).

7. The system (100) as claimed in claim 5, wherein the emergency discharge circuit (EDC) (302) comprises:
a pair of diodes (D1, D2) at input voltage to receives maximum voltage either from the primary battery (104) or from the secondary battery (105) through one of the diode from the pair of diodes (D1, D2);
a Metal–Oxide–Semiconductor Field-Effect Transistor (MOSFET) (S4) receives the maximum input voltage at gate terminal; and
a latching relay (LR) (408) to close the switch (S3) upon conduction of MOSFET (S4) and establish connection between the secondary battery (109) and the high power load (108) to discharge the secondary battery (109).

8. The system (100) as claimed in claim 7, wherein the BMS (301) is communicatively coupled with the latching relay (LR) (408) to control operation of the switch (S3).
9. The system (100) as claimed in claim 1, wherein the primary battery (104) is preferably a Lead- Acid battery and the at least one secondary battery (109) is preferably a Li-ion battery.

10. The system (100) as claimed in claim 1, wherein the system (100) further comprises a DC-DC converter (201) provided in between the primary battery (104) and the at least one secondary battery (109) to maintain the charge balance or transfer the power between both the primary battery (104) and the at least one secondary battery (109).

11. The system as claimed in claim 7, wherein the high power load (108) is preferably a heater or Air conditioner.

12. A method (500) to prevent severe hazards due to battery system failure in hybrids or electric vehicles, the method comprising:
detecting (501), by a two level water sensor (303) positioned in secondary battery (109), ingress of water level;
determining (502), whether ignition system is in ON state or OFF state, when ignition system is in OFF state,
sending (503), by battery management system (301) of the secondary battery (109), water level alerting signal (111) to a vehicle control unit (105) wake up;
sending (504), by the VCU (105), the water level alerting signal to Body Control Module (103) to wake up the BCM (103);
determining (505), by the BCM (103), whether all control lines (112, 113, 114) communicates with a plurality of auxiliary loads (101, 102 and 108);
connecting (506), by opening switch (S1) and closing switch (S2) or switch (S3), the secondary battery (109) with the plurality of auxiliary loads (101, 102 and 108);
discharging (507) the secondary battery (109) through the connected the plurality of auxiliary loads (101, 102 and 108) to prevent hazard in the secondary battery (109).

13. The method (500) as claimed in claim 12, wherein the determining (502), further comprises:
when the ignition system is in ON state indicating communication between the secondary battery (109) via the BMS (301) with the VCU (105) and the BCM (103):
determining (505), by the BCM (103), whether all control lines (112, 113, 114) communicates with a plurality of auxiliary loads (101, 102 and 108);
connecting (506), by opening switch (S1) and closing switch (S2) and switch (S3), the secondary battery (109) with the plurality of auxiliary loads (101, 102 and 108);
discharging (507) the secondary battery (109) through the connected the plurality of auxiliary loads (101, 102 and 108) to prevent hazard in the secondary battery (109).

14. The method as claimed in claim 12, wherein the determining (505) further comprises:
when the VCU (105) is not communicating with the BMS (301) of the secondary battery (109), the method comprises:
activating (508) an Emergency Discharge Circuit (EDC) (302);
closing (509), upon activation of the EDC (302), the switch (S3) where the switch (S1 and S2) remain in default state to establish connection between the secondary battery (109) with a high power load (108) from the plurality of auxiliary loads (101, 102 and 108); and
discharging (510), by the high power load (108), the secondary battery (109) to prevent hazards.
15. The method (500) as claimed in claim 14, wherein the activating (508) the emergency discharge circuit (EDC) (302) comprises:
receiving maximum input voltage either from the primary battery (104) or from the secondary battery (109) through one of the diode from a pair of diodes (D1, D2);
receiving the maximum input voltage at a Metal–Oxide–Semiconductor Field-Effect Transistor (MOSFET) (S4) gate terminal;
closing the switch (S3) by a latching relay (LR) (408) upon receiving input voltage from the MOSFET (S4);
establishing connection between the secondary battery (109) and the high power load (108) to discharge the secondary battery (109).