TECHNICAL FIELD
[0001] The present subject matter described herein, relates to an electric vehicle. More particularly, the present subject matter provides a system and a method to prohibit un-authorized access and to increase safety of a traction battery pack in the electric vehicle.
BACKGROUND
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] In electric vehicles, a traction battery pack is provided which is primary energy source for providing energy for traction of vehicle. The traction battery pack has a battery string having a plurality of battery modules connected in series with each other. Generally, the traction battery pack is controlled by the external electronic modules, such as Electronic Control unit (ECU) or Vehicle control unit (VCU) from outside the traction battery pack. The external electronic module operates passive protection devices, such as contactor or relay to draw voltage from the traction battery pack. These external electronic modules are 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.
[0004] Further, Master Batter Management System (BMS) communicates with slave BMS to collect the cell data and transmit to Vehicle Control Unit (VCU) for further analysis and protection function. So, the master BMS only

monitors and communicates safety functions to the VCU but passive protection devices are controlled by the VCU only.
[0005] As shown in the fig. 1, the passive protection relays 106, 107 that are high voltage (HV) relays are directly operated by VCU (Vehicle Control Unit). Whenever there is a requirement to withdraw the voltage from the traction battery pack 100, the VCU 105 energizes relay coils 106a, 107a present in the positive relay 106 and the negative relay 107 in a particular sequence including pre-charge relay. The energized relay coils 106a, 107a of the positive relay 106 and the negative relay 107 respectively close the normally-opened (N/O) switch 106b, 107b to make an electric connection of the positive relay 106 with a positive terminal (HV+) of the traction battery pack 100 and an electric connection of the negative relay 107 with negative terminal (HV-) of the traction battery pack 100. With closing of the normally-opened switches 106b, 107b of the relays 106, 107, the system completes the connection path between the traction battery pack 100 and the High voltage connector 103 to supply voltage to operating units of the electric vehicle.
[0006] As explained above in the fig. 1, the voltage can be withdrawn from the traction battery pack 100 by making connection with external electronic control modules.
[0007] The above mentioned system has several limitations and technical disadvantages:
[0008] In the current system of the traction battery pack, by removing the auxiliary battery supply terminal (all VCUs are OFF) and using the external low voltage power supply to drive the passive protection devices, the HV of battery pack can be accessed through junction box or directly connecting to battery terminal without triggering any diagnostic trouble code (DTC) in the vehicle controllers (such as VCU, BCU, TCU etc.). After accessing the high voltage of the traction battery pack in an unauthorized way, the traction battery pack can be

misused via overcharging, over discharging, which may result into severe safety concerns such as explosion, fire, etc.
[0009] Therefore, there is a need of a system that prohibits un-authorised access to the traction battery pack by simply supplying external power. This can be achieved by removing complete dependency of traction battery pack on the external electronic control modules.
OBJECTS OF THE DISCLOSURE
[0010] Some of the objects of the present disclosure, which at least one embodiment herein satisfy, are listed herein below.
[0011] The principal object of the present invention is to provide a system for a traction battery pack to prohibit un-authorised access of the traction battery pack by supplying external voltage for activation of the passive protection devices.
[0012] Another object of the present invention is to provide a system where activation of the passive protection devices depends upon the Master Battery Management System (BMS) of the traction battery pack.
[0013] Another object of the present invention is to provide a system where the passive protection devices are activated only when the master BMS performs all safety checks on the traction battery pack and on the electric vehicle.
[0014] These and other objects and advantages will become more apparent when reference is made to the following description and accompanying drawings.
SUMMARY
[0015] This summary is provided to introduce concepts related to a system for prohibiting un-authorised access and to increase safety of a traction battery pack of an electric vehicle. The concepts are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

[0016] In an embodiment, the present subject matter relates to a system to prohibit un-authorized access and to increase safety of a traction battery pack of an electric vehicle. The system comprising a vehicle control unit (VCU) that is coupled to an auxiliary battery and the traction battery pack of the electric vehicle. The traction battery pack comprising a master battery management system (BMS) that is coupled with a plurality of slave BMS that are coupled to a plurality of battery modules. The traction battery pack further includes a positive side relay and a negative side relay that are connected with the VCU to receive operating input voltage to energize relay coils such as positive side relay and the negative side relay to make an electric connection between positive terminal and negative terminal of the traction battery pack and high voltage connector by closing normally opened (N/O) switches available in the relays. Further, a positive side sub relay is provided in between the positive side relay and the VCU. The positive side sub relay receives operating input voltage from the master BMS. A negative side sub relay provided in between the negative side relay and the VCU. The negative side sub relay receives operating input voltage from the master BMS. At an event of starting of the electric vehicle, the master BMS which is in communication with the VCU of the electric vehicle, verifies all safety parameters with the VCU via CAN bus communication mode, upon affirmation from the VCU over the safety parameters, the positive side sub relay and the negative side sub relay receives operating input voltage from the master BMS so as to energize relay coils to close normally opened (N/O) switches to connect the positive side relay and the negative side relay with the VCU to receive operating input voltage and to make electric connection between the positive and negative terminal of the traction battery pack and the high voltage connector. The safety parameters can be related to high voltage inter-lock (HVIL) monitoring, theft, crash, unique identification number (UIN), amongst various others.
[0017] In an aspect, the VCU is coupled with the auxiliary battery to supply operating input voltage to the positive side relay and the negative side relay.

[0018] In an aspect, the master BMS is coupled with the VCU via CAN network.
[0019] Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The illustrated embodiments of the subject matter will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. The following description is intended only by way of example, and simply illustrates certain selected embodiments of devices, systems, and methods that are consistent with the subject matter as claimed herein, wherein:
[0021] Fig. 1 illustrates conventional architecture of traction battery pack; and
[0022] Fig. 2 illustrates architecture of traction battery pack with low voltage relays in connection with high voltage relays, in accordance with an embodiment of the present subject matter.
[0023] 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 disclosure described herein.
DETAILED DESCRIPTION
[0024] 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.
[0025] 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.
[0026] 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.
[0027] 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.
[0028] 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.

[0029] 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.
[0030] Non-limiting Definitions
[0031] 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 understating of the present disclosure.
[0032] Master Battery Management System: A system which is any electronic system 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.
[0033] These and other advantages of the present subject matter would be described in greater detail with reference to the following figures. It should be noted that the description merely illustrates the principles of the present subject matter. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described herein, embody the principles of the present subject matter and are included within its scope.
[0034] Main objective of the present invention is to provide a system to prohibit un-authorised access and to increase safety of a traction battery pack of an electric vehicle.
[0035] The present invention can be implemented in any electric vehicle having traction battery pack. Further, the present invention overcomes all the

technical problems as mentioned in the background section by providing a pair of sub relays that are connected with input voltage supply of main relays. Further, the pair of sub relays are controlled by the master BMS.
[0036] Exemplary Implementations
[0037] To this, as shown in fig. 2, a system for a traction battery pack 200 for an electric vehicle is explained. The system comprises a traction battery pack 200 and a Vehicle Control Unit (VCU) 205. The output of the traction battery pack 200 is connected with High Voltage (HV) connector 204 to operate the electric vehicle. The vehicle control unit (VCU) 205 is coupled to an auxiliary battery and the traction battery pack 200. The traction battery pack 200 comprises a master battery management system (BMS) 201 that is coupled with a plurality of slave BMS 202 to check safety functions a plurality of battery modules. Further, the master BMS 201 is coupled with the VCU 205 via a CAN network or CAN bus. The VCU 205 is coupled with the low voltage connector 203 which is coupled with auxiliary battery to supply low voltage, i.e., 12V to the traction battery pack 200 to make a connection between the HV connector 204 and the traction battery pack 200.
[0038] The traction battery pack 200 further includes a positive side relay 206 and a negative side relay 207 that are provided in between positive terminals (HV+) of the traction battery pack 200 and the HV connector 204 and negative terminals (HV-) of the traction battery pack 200 and the HV connector 204, respectively. The positive side relay 206 and the negative side relay 207 include a relay coil 206a, 207a and a normally opened (N/O) switch 206b, 207b to make connections between the traction battery pack 200 and the HV connector 204. The positive side relay 206 and the negative side relay 207 are connected with the VCU 205 via Low voltage connector 203 to receive operating input voltage from the auxiliary batter to energize the relay coils 206a, 207a present in the positive side relay 206 and the negative side relay 207. Upon receiving the operating input voltage from the VCU 205, the relay coils 206a, 207a are energized, resulting into

closing of normally opened (N/O) switches 206b, 207b to make an electric connection between the positive terminals and negative terminals of the traction battery pack 200 with the HV connector 204.
[0039] To break direct connection between the VCU 205 and the positive side relay 206, a positive side sub relay 208 is provided in between the positive side relay 206 and the VCU 205. The positive side sub relay 208 receives operating input voltage from the master BMS 201. The positive side sub relay 208 has a relay coil 208a and a normally opened (N/O) switch 208b to make connection upon receiving energized input voltage.
[0040] Similarly, a negative side sub relay 209 is provided in between the negative side relay 207 and the VCU 205 to break the direction connection. The negative side sub relay 209 receives operating input voltage from the master BMS 201. The negative side sub relay 209 has a relay coil 209a and a normally opened (N/O) switch 209b to make connection upon receiving energized input voltage.
[0041] In an aspect, the positive side relay 206 and the negative side relay 207 are high voltage operated relays. The positive side sub relay 208 and the negative side sub relay 209 are low voltage operated relays.
[0042] At an event of starting of the electric vehicle, the master BMS 201 checks all safety checks, such as High Voltage Interlock (HVIL), crash, and other safety checks of the vehicle. The master BMS 201 verifies all the safety checks with the VCU 205 via CAN bus. Upon affirmation from the VCU 205 over the safety parameters, the positive side sub relay 208 receives operating input voltage from the master BMS 201 so as to energizes relay coil 208a of the positive side sub relay 208 to close normally opened (N/O) switches 208b to connect the positive side relay 206 with the VCU 205 to receive operating input voltage. Similarly, the negative side sub relay 209 receives operating input voltage from the master BMS 201 so as to energize relay coil 209a of the negative side sub relay 209 to close normally opened (N/O) switches 209b to connect the negative side relay 207 with the VCU 205 to receive operating input voltage.

[0043] Upon receiving the operating input voltage from the VCU 205 from the low voltage connector 203, the relay coil 206a energize to close normally opened (N/O) switch 206b to connect the positive terminal (HV+) of the traction battery pack 200 with the positive terminal of the HV connector. Similarly, the negative side relay 207 receives operating input voltage from the VCU 205 to energizes the relay coil 207a to close normally opened (N/O) switch 207b to connect the negative terminal (HV-) of the traction battery pack 200 with the negative terminal of the HV connector 204.
[0044] 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."
[0045] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.

We claim

1. A system to prohibit un-authorized access of a traction battery pack (200) of an electric vehicle, the system comprising:
a vehicle control unit (VCU) (205) coupled to an auxiliary battery and the traction battery pack (200), the traction battery pack (200) comprising:
a master battery management system (BMS) (201) coupled with a plurality of slave BMS (202) that are coupled to a plurality of battery modules;
a positive side relay (206) and a negative side relay (207) connected with the VCU (205) to receive operating input voltage to energize relay coils (206a, 207a) present in the positive side relay (206) and the negative side relay (207) to make an electric connection with positive terminal and negative terminal of the traction battery pack (200) by closing normally opened (N/O) switches;
a positive side sub relay (208) provided in between the positive side relay (206) and the VCU (205), where the positive side sub relay
(208) receives operating input voltage from the master BMS (201);
a negative side sub relay (209) provided in between the negative side relay (207) and the VCU (205), where the negative side sub relay
(209) receives operating input voltage from the master BMS (201);
at an event of starting of the electric vehicle, the master BMS (201) verifies all safety parameters with the VCU (201) via CAN bus, upon affirmation from the VCU (201) over the safety parameters, the positive side sub relay (208) and the negative side sub relay (209) receive operating input voltage from the master BMS (201) to energize relay coils (208a, 209a) to close normally opened (N/O) switches (208b, 209b) to connect the positive side relay (206) and the negative side relay (207) with the VCU (205) to receive operating input voltage.

2. The system as claimed in claim 1, wherein the safety parameters are related to high voltage inter-lock (HVIL) monitoring, theft, crash, or unique identification number (UIN).
3. The system as claimed in claim 1, wherein the master BMS (201) supplies low voltage to power up the sub-relays.
4. The system as claimed in claim 1, wherein the VCU (205) is coupled to the auxiliary battery to supply operating input voltage to the positive side relay (206) and the negative side relay (207).
5. The system as claimed in claim 1, wherein the master BMS (201) is coupled to the VCU (205) via CAN network.