The present subject matter described herein, relates to an electric vehicle. More particularly, the present subject matter provides a traction battery pack and a method to detect un-authorized opening of cover of the traction battery pack when auxiliary low voltage is disconnected, for example, 12V supply source is disconnected.
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 a primary energy source for providing energy for traction of vehicle. The traction battery pack has a battery string comprising of plurality of battery modules connected either in series or in parallel or in any combination with each other. A plurality of cells combined with each other to form a battery module and a plurality of battery modules combined with each other to form a battery pack or a traction battery pack. The traction battery pack generates a high voltage (HV) for traction of an electric motor for traction of the electric vehicle. The traction battery pack can be controlled by the electronic modules, such as electronic control unit (ECU) or vehicle control unit (VCU) from outside the traction battery pack, or can be controlled by electronic module, such as battery management system (BMS) from inside the traction battery pack. The electronic module operates passive protection devices to draw current from the traction battery pack. These 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] A battery management system (BMS) is provided to communicate with a plurality of slave BMS of the plurality of battery modules to collect the cell data and optionally transmit the same to vehicle control unit (VCU) for further analysis and protection functions. Further, the protection functions are controlled by the VCU only, BMS only, or in combination by the VCU and the BMS.
[0005] The traction battery pack supplies high current for traction of vehicle. The VCU or the BMS controls the output of the traction battery pack.
[0006] Technical problem existing with traction battery pack is detection of un-authorized access of the traction battery pack.
[0007] Existing technologies detect the un-authorized access of the traction battery pack and log the same into the memory for further processing. However, the disadvantage associated with the existing technologies is that a low voltage supply is required for detection and logging. With the existing technologies, the un-authorized access can be detected only when the traction battery pack is coupled with auxiliary battery supplying low voltage for functioning of the BMS. In case of deliberate or accidental disconnection of the auxiliary battery supply, the existing technologies do not detect the un-authorized access of the traction battery pack or opening of the cover of the traction battery pack.
[0008] To change the battery modules, generally, the traction battery pack is disassembled from the vehicle by disconnecting all connections with VCU and the auxiliary battery. In this case, it becomes cumbersome to detect authorized or un¬authorized access of the traction battery pack.
[0009] Therefore, there is a need of a circuit for a traction battery pack and a method thereof that can detect un-authorized access of the traction battery pack even when the complete low voltage supply source is disconnected from BMS, VCU or traction battery pack.
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 subject matter is to provide a circuit which is coupled with BMS of the traction battery pack to detect opening of battery cover in the traction battery pack.
[0012] Another object of the present subject matter is to provide a method for detecting opening of the battery cover in an un-authorised event.
[0013] Another object of the present subject matter is to provide a system for detecting opening of battery cover by determining status of fuse present in the circuit.
[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 circuit of traction battery pack and a method to detect un-authorized opening of cover of the traction battery pack. 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 traction battery pack comprising a battery management system (BMS) and a cover open detection circuit coupled with the BMS to inform status of battery cover. The cover open detection circuit comprising a power source; a latchable switch (SI) connected with the power source; a first resistor, a second resistor, and a cover switch (S2) are connected in series with the latchable switch (SI), where one end of the cover switch is connected with ground connection; a switch (S3) connected in parallel with the first resistor where one end of the switch (S3) is connected with the latchable switch (SI); a fuse provided in between the ground connection and a terminal joining one end of the second resistor and other end of the switch (S3) to provide path towards ground when the cover switch (S2) is open.

[0017] In an aspect, the switch (S3) is MOSFET type switch, where gate-source voltage (VGS) is same as voltage drop across the second resistor. The drain terminal (D) of the MOSFET is connected with the voltage and source terminal (S) of the MOSFET is connected with the terminal of the fuse.
[0018] In an aspect, the switch (S3) conducts and establish shortest path between the power source and the ground connection.
[0019] In an aspect, the fuse blows off due to high current coming from the switch (S3).
[0020] In an aspect, the second resistor has higher resistance value than the first resistor so that current passing through the first and second resistor is lower than current value of the fuse.
[0021] In an aspect, the BMS monitors status of the fuse upon receiving low voltage supply to determine status of the battery cover.
[0022] In an aspect, the BMS is coupled with the cover open detection circuit via pull up resistor to monitor the status of the fuse.
[0023] In an aspect, the power source is at least one of a coin cell, cylindrical cell, pouch cell, prismatic cell.
[0024] In an aspect, the latchable switch (S1) is controlled by the BMS.
[0025] In an embodiment, the present subject matter relates to a method for operating a cover open detection circuit during un-authorized opening of battery cover of a traction battery pack. The method comprising opening of a cover switch (S2) when the battery cover is opened and a latchable switch (SI) is closed; closing a switch (S3) when current from a power source flows through a first resistor and a second resistor; establishing a shortest path between the power source and ground connection by closing the switch (S3); and blowing off a fuse by supplying current more than rated current value of the fuse through the established shortest path.

[0026] In an aspect, the conducting the switch (S3) by voltage drop across the second resistor.
[0027] In an aspect, the switch (S3) is MOSFET type switch, where gate-source voltage (VGS) is same as voltage drop across the second resistor. The drain terminal (D) of the MOSFET is connected with the latchable switch (SI), and source terminal (S) connected with the terminal of the fuse.
[0028] In another embodiment of the present subject matter relates to method for determining un-authorized opening of battery cover of a traction battery pack. The method comprising monitoring, by a BMS, status of fuse in cover open detection circuit; and determining, by the BMS, un-authorized opening of the battery cover of the traction battery pack when the status of the fuse is blown.
[0029] 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
[0030] 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:
[0031] Fig. 1 illustrates architecture of traction battery pack with cover open detection circuit, in accordance with an embodiment of the present subject matter;
[0032] Fig. 2 illustrates a method of working of cover open detection circuit at an event of un-authorized cover opening of the traction battery pack, in accordance with an embodiment of the present subject matter; and

[0033] Fig. 3 illustrates a method for detecting traction battery cover status by monitoring status of cover open detection circuit, in accordance with an embodiment of the present subject matter.
[0034] 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
[0035] 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.
[0036] 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.
[0037] 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.
[0038] 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.
[0039] 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.
[0040] 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.
Non-limiting Definitions
[0041] 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.
[0042] 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.
[0043] Low voltage: Less than 60V
[0044] High voltage: 60V or more
[0045] MOSFET: A metal oxide semiconductor field-effect transistor (MOSFET) is a field-effect transistor 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.
[0046] 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.
[0047] Technical objective of the present subject matter is to detect un¬authorised cover opening of the traction battery pack when there is no supply of current from outside.
[0048] The present subject matter can be implemented in any vehicle having a battery pack. Further, the present subject matter overcomes all the technical problems as mentioned in the background section by providing a cover open detection circuit having a low voltage power source, such as battery cell or coin cell to supply low voltage for working of the cover open detection circuit to detect the opening of cover and blowing off a fuse that tells BMS about the opening status of battery cover.
Exemplary Implementations
[0049] To this, as shown in fig. 1, an architecture of a traction battery pack 300 for an electric vehicle is explained. The architecture of traction battery pack 300 comprises a battery management system (BMS) 100 coupled with a cover open detection circuit 200. The BMS 100 is coupled with the cover open detection

circuit 200 via pull up resistor (Rup) circuit. The Pull up resistor (Rup) changes default high state value of the BMS to low state value to indicate changes at the cover open detection circuit 200. Further, working of pull up resistor with micro-controller is well known to a person skilled in the art. Therefore, to avoid ambiguity in the present subject matter, the present complete specification discloses only subject matter related invention. Pull up resistor is placed to ensure high state at controller input in case fuse is blown. If fuse is intact, controller input stays in low state.
[0050] The cover open detection circuit 200 comprising a power source 201 and a latchable switch (SI) 202 connected with the power source 201. The cover open detection circuit 200 further comprises a first resistor (Rl) 203, a second resistor (R2) 204, and a cover switch (S2) 205 connected in series with the latchable switch (SI) 202. Further, one end of the cover switch (S2) 205 is connected with the resistor (Rl) 203 and other end is connected with a ground connection 208. A switch (S3) 207 is connected in parallel with the first resistor (Rl) 203 where one end of the switch (S3) 207 is connected with the latchable switch (SI) 202 and other end connected with a terminal 209 joining one end of the second resistor (R2) 204. A fuse 206 is provided in between the ground connection 208 and the terminal 209 joining one end of the second resistor (R2) 204 and other end of the switch (S3) 207 to provide a path towards ground when the cover switch (S2) 205 is opened.
[0051] The switch (S3) 207 is MOSFET type switch, specifically, NMOS type switch. In the NMOS type MOSFET switch source voltage terminal (VG) is connected with junction point 'X' joining the first resistor (Rl) 203, the second resistor (R2) 204, and the cover switch (S2) 204. The junction point 'X' has same voltage as it is across the second resistor (R2) 204 or voltage after the first resistor (Rl) 203 or at positive terminal of the second resistor (R2) 204. The drain terminal (D) is connected with the latchable switch (SI) 202 and source terminal (S) connected with the terminal 209 of the fuse 206.

[0052] In an embodiment, resistance value of the second resistor (R2) 204 is higher than resistance value of the first resistor (Rl) 203.
[0053] In an embodiment, the fuse 206 having low current rating value.
[0054] In an embodiment, the latchable switch (SI) is controlled by the BMS 100. Control means open and close of the switch SI is done by the controller. In the present disclosure, the latchable switch (SI) is normally closed type switch. This switch is provided to enable authorized personal to open the battery pack without blowing the fuse 206. This latchable switch (SI) 202 can only be operated by authorized person and cannot be operated by anyone other than the authorized ones. Once the latchable switch (SI) 202 is opened, the fuse 206 doesn't blow, as no power supply is available.
[0055] In an embodiment, the power source 201 is at least one of a coin cell, cylindrical cell, pouch cell, prismatic cell. The power source 201 is low voltage power source, for example, 1.7V, 3.3V, 5V, 10V, or 12V.
[0056] In operation, when battery cover is closed, the cover switch (S2) 205 remain closed. The cover switch (S2) 205 is provided inside the battery cover and it can be plunger type switch or any spring based switch which is in closed state when pack cover is closed. When cover switch (S2) 205 is closed, the current from the power source 201 flows through the first resistor (Rl) 203. As current takes shortest path, the current which is very low current passes through the cover switch (S2) 205 and reaches to ground connection 208.
[0057] When the battery cover is opened, the cover switch (S2) 205 opens and breaks the shortest path for flow of current from the power source 201. The current now flows through the first resistor (Rl) 203, the second resistor (R2) 204 and the fuse 206 and reaches the ground connection 208.
[0058] For example, the power source 201 is of 3.3V. The current passed through the fuse 206 is 3mA when the first resistor (Rl) 203 is IkQ and the second resistor (R2) 204 is 10 kQ:
I = V/R

I = 3.3/(lk+10k)
I = 3mA
[0059] For example, the fuse 206 has current value of 5mA. The current, i.e., 3mA easily pass through the fuse 206 without blowing off the same.
[0060] To avoid blowing off the fuse 206, the current is passed through first resistor (Rl) 203 and second resistor (R2) 204. Because of high equivalent resistance of the path, the amount of current passing through first resistor (Rl) 203, second resistor (R2) 204 and fuse 206 is very less, which doesn't blow up the fuse 206.
[0061] The voltage drop across the second resistor (R2) 204 or in between the first resistor (Rl) 203 and the second resistor (R2) 204 or at junction point 'X' is sufficient to drive the switch (S3) 207. The voltage source connection from the junction point 'X' closes the switch (S3) 207 and establishes a shortest path between the power source 201 and the ground connection 208 via terminal 209 and the fuse 206. The current passing through the switch (S3) 207 blows off the fuse 206 as the current is very high as compared to rated current value of the fuse 206.
[0062] For example, the power source 201 has voltage 3.3 V and the switch (S3) 207 has very low resistance, for example, lOmQ.
I=V/R
I = 3.3/10mQ
I = 330A
[0063] The current value of the fuse 206 is 5mA. When current of 330A passes through the fuse 206 by choosing shortest path from the power source 201 to the ground connection 208, the fuse 206 blows off.
[0064] Once the fuse is blown and the traction battery pack 300 is connected with the low voltage supply, such as auxiliary battery, the BMS 100 receives status of the fuse 206 through Pull up resistor circuit and update the status of

cover in the memory or changes the pin state. For example, when pin of the micro-controller (which is BMS) connected with the cover open detection circuit is high it means, the cover was opened and when the pin is low it means cover was closed.
[0065] The traction battery pack (300) as claimed in claim 1, wherein the BMS (100) monitors status of the fuse (206) upon receiving low voltage supply to determine status of the battery cover.
[0066] Fig. 3 illustrates a method 400 for operating cover open detection circuit at an event of un-authorized cover opening of the traction battery pack. The method comprising:
[0067] At step 401, the method 400 includes closing the latchable switch (SI) 202 at the end of assembly of the traction battery pack 300.
[0068] At step 403, the method 400 includes determining whether battery cover is opened or not. When the battery cover is not opened, the method proceeds to end. When the battery cover is opened, the method proceeds to step 405.
[0069] At step 405, the method 400 includes establishing that the cover switch
(52) 205 is opened.
[0070] At step 407, the method 400 includes flowing current through the first resistor (Rl) and the second resistor (R2) to conduct the switch (S3). The switch
(53) 207 is conducted when current from a power source 201 flows through a first
resistor 203 and a second resistor 204. As value of second resistor (R2) 204 is
high, voltage drop across it is also high. As the switch (S3) 207 is parallel to
second resistor (R2) 204, the voltage drop across switch (S3) 207 also becomes
high, which is above a specific threshold. This causes switch (S3) 207 to become
conductive. Further, the switch (S3) 207 establishes a shortest path between the
power source 201 and ground connection 208 through the fuse 206.

[0071] At step 409, the method 400 includes blowing off of the fuse 206 by flow of current more than the rated current value of the fuse 206 through the established shortest path.
[0072] Once the fuse is blown off, the path to ground is open circuit. The BMS 100 monitors the status of fuse 206 when low voltage is supplied to the BMS 100.
[0073] The method 500 illustrates how the BMS receives input from the cover open detection circuit about fuse status to detect opening of the battery cover.
[0074] At step 501, the method 500 includes monitoring the status of fuse by the BMS 100 when low voltage is supplied. The cover open detection circuit 200 is connected to the BMS 100 through a pull up resistor circuit to monitor the status of the fuse.
[0075] At step 503, the method 500 includes determine status of battery cover based on the status of the fuse. For example, when fuse is not blown, the fuse keeps state of the micro-controller pin as low. When the fuse is blown, the pull up resistor circuit changes the pin to high state to indicate status of the fuse.
[0076] With the present subject matter, it becomes possible to determine cover opening action by the BMS. Further, this action can be accessed by any computing device, for example, computer to check un-authorized access of the traction battery pack.
[0077] In an implementation, the BMS may not allow supply of high voltage for traction of vehicle when the traction battery pack is accessed in an un¬authorised manner.
[0078] 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."
[0079] 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:

A traction battery pack (300) comprising:
a battery management system (BMS) (100);
characterized in that:
a cover open detection circuit (200) coupled with the BMS (100) to inform status of battery cover, the cover open detection circuit (200) comprising:
a power source (201);
a latchable switch (SI) (202) connected with the power source (201);
a first resistor (203), a second resistor (204), and a cover switch (S2) (205) are connected in series with the latchable switch (SI) (202), where one end of the cover switch (205) is connected with ground connection (208);
a switch (S3) (207) connected in parallel with the first resistor (203) where one end of the switch (S3) (207) is connected with the latchable switch (SI) (202);
a fuse (206) provided in between the ground connection (208) and a terminal (209), joining one end of the second resistor (204) and other end of the switch (S3) (207) to provide path towards ground when the cover switch (S2) (205) is opened.
The traction battery pack (300) as claimed in claim 1, wherein the switch (S3) (207) is MOSFET type switch, where gate-source voltage (VGS) is same as voltage drop across the second resistor (204), drain terminal (D) is connected with the voltage source (201) and source terminal (S) is connected with the terminal (209) of the fuse (206).
The traction battery pack (300) as claimed in claim 1, wherein the switch (S3) (207) conducts and establishes shortest path between the power source (201) and the ground connection (208), when the cover switch (S2) (205) is opened.

4. The traction battery pack (300) as claimed in claim 3, wherein the fuse (206) blows off due to higher than rated current coming from the switch (S3) (207).
5. The traction battery pack (300) as claimed in claim 1, wherein the second resistor (204) has high resistance value than the first resistor (203) so that current passing through the second resistor (204) is lower than rated current value of the fuse (206).
6. The traction battery pack (300) as claimed in claim 1, wherein the BMS (100) monitors status of the fuse (206) upon receiving low voltage supply to determine status of the battery cover.
7. The traction battery pack (300) as claimed in claim 6, wherein the BMS (100) is coupled with the cover open detection circuit (200) via pull up resistor to monitor the status of the fuse (206).
8. The traction battery pack (300) as claimed in claim 1, wherein the power source (201) is at least one of a coin cell, cylindrical cell, pouch cell, prismatic cell.
9. The traction battery pack (300) as claimed in claim 1, wherein the latchable switch (SI) (202) is controlled by the BMS (100).
10. A method (400) for operating a cover open detection circuit (200) during un-authorized opening of battery cover of a traction battery pack (300), the method comprising:
opening (405) of a cover switch (S2) (205) when the battery cover is opened and a latchable switch (SI) (202) is closed;
closing (407) a switch (S3) (207) when current from a power source (201) flows through a first resistor (203) and a second resistor (204);
establishing a shortest path between the power source (201) and ground connection (208) by conducting the switch (S3) (207); and
blowing off (409) a fuse (206) by supplying current more than rated current value of the fuse (206) through the established shortest path.
11. The method (400) as claimed in claim 10, wherein the conducting (407) the
switch (S3) (207) by voltage drop across the second resistor (204).

12. The method (400) as claimed in claim 10, wherein the switch (S3) (207) is MOSFET type switch, where gate-source voltage (VGS) terminal is same as voltage drop across the second resistor (204), wherein the drain terminal (D) is connected with the latchable switch (SI) (202), and source terminal (S) is connected with the terminal (209) of the fuse (206).
13. A method (500) for determining un-authorized opening of battery cover of a traction battery pack (300), the method (500) comprising:
monitoring (501), by a BMS (100), status of fuse (206) in cover open detection circuit (200); and
determining (502), by the BMS (100), un-authorized opening of the battery cover of the traction battery pack (300) when the status of the fuse (206) is blown.