Description:TECHNICAL FIELD
[0001] The present subject matter relates generally to a battery pack. More particularly but not exclusively the present subject matter relates to thermal management of the battery pack.

BACKGROUND
[0002] With the advancement in technology, an electric or hybrid electric vehicle makes use of one or more power sources to drive the vehicle. The one or more powers source is a battery pack to provide power to run a motor which in turn runs one or more wheels of the vehicle. The one or more power sources in such hybrid electric vehicles are prone to damage due to increase in temperature as the usage increases.
[0003] The increase in temperature of the battery pack leads to poor performance of the vehicle and cause thermal runaway, in turn creating unsafe driving conditions for a user. Thermal runaways are caused due to an abnormal increase in temperature inside the battery pack which may lead to the melting or excessive damage to a plurality of cells of the battery pack and may even cause the plurality of cells of the battery pack to explode. In case of charged Li-ion cells with high energy density, the thermal runaway is a fast, violent, self-accelerating chemical reaction of electrodes and electrolyte which releases high amounts of heat and gas. A better cooled battery pack ensures the welfare and safety of the user and as well as leads to an increase in durability and health of the plurality of cells of the battery pack.
[0004] The battery pack includes the plurality of cells which are connected through one or more interconnectors. The one or more interconnectors provide an electrical connection between each of the one or more cells. The plurality of cells are arranged in a module consisting of a top casing and a bottom casing. The plurality of cells are welded to a metal strip known as the interconnector, forming a battery pack. The one or more interconnectors are connected to a Battery management system (BMS ). The BMS obtains individual parameters of the plurality of cells to monitor the State of Charge (SoC) and State of Health (SoH) of the battery pack. An efficient thermal management system can monitor a plurality of parameters associated with the battery pack. The plurality of parameters may comprise at least one of temperature, voltage, charging current, and the like. In an embodiment, the plurality of parameters may be monitored during at least one of a riding condition of the vehicle, a charging condition of the vehicle, or a non-riding condition.
[0005] It is imperative to obtain precise temperature parameters in order to achieve a more effectively cooled battery pack for performance and durability with good health of the plurality of cells in the battery pack. To achieve the above objective, determining the appropriate positioning of temperature sensing elements is essential.
[0006] Conventionally, temperature sensing elements are pasted onto the plurality of cells of the battery pack using a sticker or adhesive. However, an improper application of the sticker or adhesive can result in shorting of the temperature sensing elements with the plurality of cells of the battery pack. This results in detection of incorrect values of temperature by the temperature sensing element disposed in the battery pack. Which further leads to improper reading of the temperature and improper optimisation of parameters like State of Charge (SoC) and State of Health (SoH), increasing risks of thermal runaway and jeopardizing the safety of the user.
[0007] In a known art, a temperature sensor is provided with a sensor section that is inserted from an outside of a chassis and fixed to a through hole for fixing the sensor, and a front-end portion of the sensor section thermally contacts a region to be measured of the cell. A wire that is drawn from a portion, which is exposed to an outside of the chassis of the sensor section is set up inside a groove formed on an outer peripheral surface of the chassis wall. In yet another known prior art, a sensor fixing hole is formed in a top wall of a battery case, a temperature sensor unit is detachably inserted into the sensor fixing hole and fixed. A tip of a temperature detecting part of the temperature sensor unit is brought into contact with battery cells within the battery case to detect the temperature of the battery cells. Even if the temperature sensor unit malfunctioned, only the temperature sensor unit is replaceable without replacing the temperature sensor unit together with a battery. However, these means are not able to solve the problem explained above. Therefore, there is need to provide a means of attaching the temperature sensing element with the one or more cell with utmost durability. Thus, there is a need to overcome the above-mentioned problems and other problems of known art.
[0008] Moreover, conventionally, temperature sensing elements are pasted onto the plurality of cells of the battery pack in an arbitrary manner to read and obtain temperature parameters of the battery pack. This leads to an increase in the number of temperature sensing elements being used, which is responsible for an increase in weight of the battery pack. An unnecessary increase in weight of the battery pack can lead to a poor performance of the vehicle. Further, an unnecessary increase in components in the battery pack can lead to an increase in the cost of production of the battery pack.
[0009] Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of described systems with some aspects of the present disclosure, as set forth in the remainder of the present application and with reference to the drawings.

SUMMARY OF THE INVENTION

[00010] According to embodiments illustrated herein, the present invention provides a battery pack with a plurality of cells. The plurality of cells comprises at least a first cell, a second cell, a third cell, and a fourth cell. In an embodiment, the first cell, the second cell, the third cell, and the fourth cell being selected based on a total number of the plurality of cells disposed in the battery pack and one or more dimensions of the battery pack. The battery pack comprises a plurality of temperature sensing elements being connected to each of the first cell, the second cell, the third cell, and the fourth cell. In an embodiment, the plurality of temperature sensing elements comprises at least a first temperature sensing element, a second temperature sensing element, a third temperature sensing element, and a fourth temperature sensing element.
[00011] In an embodiment, the first temperature sensing element is disposed on the first cell and the first cell is disposed adjacent to a battery pack top casing. In an embodiment, the second temperature sensing element is disposed on the second cell and the second cell is disposed at a centre of the battery pack. In an embodiment, the third temperature sensing element is disposed on the third cell and the third cell is disposed on either corners of the battery pack. In an embodiment, the fourth temperature sensing element is disposed on the fourth cell and the fourth cell is identified based on one or more hotspot regions in the battery pack, where a hotspot region is identified based on a pre-defined threshold temperature to determine areas of the battery pack that dissipate maximum temperature.
[00012] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

[00013] The details are described with reference to an embodiment of a battery pack along with the accompanying diagrams. The same numbers are used throughout the drawings to reference similar features and components.
[00014] Fig. 1 exemplarily illustrates an exploded perspective top view of a battery pack, in accordance with an embodiment of the present disclosure.
[00015] Fig. 2 exemplarily illustrates an exploded perspective side view of the battery pack, in accordance with an embodiment of the present disclosure.
[00016] Fig. 3(a) illustrates an exploded view of a battery module of the battery pack, in accordance with an embodiment of the present disclosure.
[00017] Fig. 3(b) illustrates a top view of the battery module within the battery pack, in accordance with an embodiment of the present disclosure
[00018] Fig. 3(c) illustrates a perspective side view of the battery pack, in accordance with an embodiment of the present disclosure.
[00019] Fig. 4(a) illustrates a temperature sensing element being disposed on a cell from the plurality of cells of the battery pack, in accordance with an embodiment of the present disclosure.
[00020] Fig. 4(b) illustrates an exploded view explaining the disposition of the temperature sensing element being disposed on a cell from the plurality of cells of the battery pack, in accordance with an embodiment of the present disclosure.
[00021] Fig. 4(c) illustrates various components comprising the temperature sensing element, in accordance with an embodiment of the present disclosure.
[00022] Fig. 5 illustrates a method performed by a BMS of the battery pack, in accordance with an embodiment of the present disclosure.
DETAILED DESCRIPTION
[00023] Exemplary embodiments are described with reference to the accompanying drawings. Wherever convenient, the same reference numbers are used throughout the drawings to refer to the same or like parts. While examples and features of disclosed principles are described herein, modifications, adaptations, and other implementations are possible without departing from the spirit and scope of the disclosed embodiments. It is intended that the following detailed description be considered as exemplary only, with the true scope and spirit being indicated by the following claims.
[00024] An objective of the present subject matter is to provide a battery pack comprising of a plurality of cells, with strategically placed temperature sensing elements on to a plurality of cells to obtain accurate temperature parameters of the battery pack and sense abnormal increase in the plurality of cells temperatures to prevent thermal runaway ensuring safety of a user of a vehicle having such a battery pack.
[00025] The optimum positioning of temperature sensing elements will aid in capturing an increase in the battery pack temperature due to internal reactions of the battery pack during at least one of a riding condition of the vehicle, a charging condition of the vehicle, or a non-riding condition, further aiding to achieve an effective cooling system to avoid thermal runaway ensuring safety of user. An optimum positioning of temperature sensing elements will sense temperature distribution in the battery pack which is critical to enable monitoring of the limits of the battery pack operating window, based on which an intelligent charging strategy is deduced. A minimal range of 3-5°C is permissible between the hottest cell and the coldest cell in the battery pack, otherwise this may lead to deterioration in life of the battery pack. Also, low temperature sensing can be crucial during charging process. Thus, the optimum positioning of temperature sensing elements to identify the accurate temperature of the battery pack is strategically important.
[00026] Further, another objective of the present invention is placing an optimal count of temperature sensing elements which is essential to address the unnecessary increase in components in the battery pack, reduce complexity, and reduce cost of production of the battery pack.
[00027] As per an aspect of the present subject matter, the optimal count of temperature sensing elements will be dependent on the number of plurality of cells present in the battery pack, as well as the dimensions of the battery pack. Additional temperature sensing elements will be disposed on several plurality of cells, to accurately capture the temperature of the plurality of cells in the battery pack. As per an embodiment, where plurality of battery packs are placed adjacent to each other, one or more additional temperature sensing elements apart from the six temperature sensing elements disclosed herein may be disposed on the plurality of cells that are present in the vicinity of newly created thermal hotspots or any other strategically identified location. These newly created thermal hotspots will be created due to parameters such as reduced air flow and ventilation between adjacent sides of the first casing of the battery pack, leading to an increase in temperature of the battery pack.
[00028] The location of the plurality of cells for placing the temperature sensing elements is selected by considering multiple parameters including but not limited to thermal hotspot of the battery pack, coldest region in the battery pack, median temperature of the battery pack. A hotspot region is identified based on a pre-defined threshold temperature to determine areas of the battery pack that dissipate maximum temperature. Therefore, such optimum location of disposing the temperature sensing elements and an optimum count of the temperature sensing elements increases safety of a user of a vehicle having such a battery pack. The locations of the plurality of cells are determined and positioned such that in case of a hazardous event, the nearest temperature sensing element will be able to capture the parameter of highest temperature around the vicinity of the plurality of cells at the earliest, and thus, a Battery Module Management System can take necessary action for change of mode or shut down of the battery pack to warn user. Such accurate temperature monitoring plays a crucial role in optimisation of the battery pack parameters like State of Charge (SoC) which is linked to performance of the battery pack, State of Health (SoH) which is linked to battery lifetime and to user safety aspects. The selection of the plurality of cells ensures that measurement of temperature parameter is distributed evenly in the battery pack, such a strategy also included performing an optimal cost study.
[00029] It is another objective of the present invention to provide a durable means of attaching the temperature sensing element on to the plurality of cells and at appropriate place to detect the correct and accurate temperature of the battery pack. The present subject matter aims to provide a simple attachment means of temperature sensing element which is durable, easy to assemble, easy to handle, and safe to operate for the entire life cycle of the battery pack.
[00030] As per an aspect of the present subject matter, the plurality of cells are selected to connect the plurality of temperature sensing element. The plurality of temperature sensing elements are disposed on the plurality of cells and are attached to the plurality of cells using one or more adhesive agents, where a first adhesive agent is to be pasted along a length of an exterior portion of the plurality of cells, and the temperature sensing element is mounted sandwichedly between the first adhesive agent and a second adhesive agent. The second adhesive agent is pasted such that it can hold the plurality of temperature sensing element on the exterior portion of the plurality of cells.. One adhesive agent is to ensure insulation between the plurality of cells and temperature sensing element to avoid shorting and another adhesive agent is to hold the temperature sensing element to the plurality of cells to make sure that it is securely positioned to avoid loss of contact. Such an arrangement with the first adhesive agent along with the second adhesive agent is used to ensure insulation on the plurality of cells and therefore, avoid shorting of the temperature sensing element with the plurality of cells.
[00031] As per another aspect of the present subject matter, the plurality of temperature sensing elements is attached to a centre position along the length of the plurality of cells of the battery pack. The maximum temperature is recorded at a centre of the cell at any testing condition as illustrated by the test data, therefore, concluding that the centre of the cell is the most appropriate position to place the temperature sensing element.
[00032] As per an aspect of the present subject matter, the plurality of temperature sensing elements comprises of one or more temperature sensor, and a cord set. The one or more temperature sensor is disposed on the one or more cell. The one end of the cord set having the temperature sensor is connected to at one end and another end of the cord set is connected to a base member.
[00033] As per an aspect of the present subject matter, the base member is configured to have one or more temperature sensing element coupler, the one or more temperature sensing element coupler is configured to be connected with a Battery Module Management System to receive one or more inputs from the battery pack.
[00034] As per an aspect of the present subject matter, the one or more temperature sensing element senses abnormal increase in cell temperature. This temperature is obtained by the Battery Module Management System, and the temperature captured is then compared with a first pre-determined temperature threshold value and a second pre-determined temperature threshold value by the Battery Module Management System. Based on such comparison, the Battery Module Management System will perform a plurality of functions that include a change of mode from power mode to an eco-mode or initiate shut down of the battery pack. A change of mode from power mode to an eco-mode will be performed when the obtained cell temperature is greater than the first pre-determined threshold. During the power mode, a significantly great amount of current is being drawn from the battery pack which may increase the temperature of the battery pack. Therefore, a switch to the eco-mode will limit the current being drawn from the battery pack, thereby limiting the increase in temperature of the battery pack. The Battery Module Management System will initiate shut down of the battery pack to prevent the thermal runaway, in case if the obtained temperature parameter is greater than the second pre-determined temperature threshold value. Additionally, during fast charging, if the temperature of the battery pack increases beyond a pre-determined temperature threshold value, the charging rate can be slowed down to avoid rise in temperature. Therefore, detecting accurate temperature of the battery pack aids in devising and implementing intelligent charging strategy. It is an aspect of the present invention to aid in ensuring a safer battery pack with longer life, eliminating thermal runaway, optimizing parameters like SoC and SoH. Many other improvements and modifications may be incorporated herein without deviating from the scope of the invention.
[00035] As per an aspect of the present subject matter, a battery pack includes a plurality of cells configured to form one or more battery module.
[00036] The embodiments of the present invention will now be described in detail with reference to a battery pack along with the accompanying drawings. However, the present invention is not limited to the present embodiments. The present subject matter is further described with reference to accompanying figures. It should be noted that the description and figures merely illustrate principles of the present subject matter. Various arrangements may be devised that, although not explicitly described or shown herein, encompass the principles of the present subject matter. Moreover, all statements herein reciting principles, aspects, and examples of the present subject matter, as well as specific examples thereof, are intended to encompass equivalents thereof.
[00037] Fig.1 exemplarily illustrates an exploded top perspective view of a battery pack 100. Fig. 2 exemplarily illustrates an exploded perspective side view of the battery pack, in accordance with an embodiment of the present disclosure. For the sake of brevity, Fig. 1 and Fig. 2 are explained together.
[00038] A battery pack casing 102 protects one or more battery modules 100a (shown in fig.3a) from outside environment and prevents it from getting damaged. The battery module 100a includes plurality of cells 104a (shown in fig.3a) disposed in one or more holder 104 to hold it still in its required position, during the operation of the vehicle (not shown) and also to maintain the required cell arrangement and cell spacing. The battery module 100a includes the plurality of cells 104a, one or more cell holder 104, and one or more interconnectors 106. The plurality of cells 104a provides the electric energy to drive a vehicle (not shown). The one or more cell holder 104 is provided with one or more voltage sensing points 112 for one or more interconnectors 106 to be placed. The one or more interconnectors 106 are used to make electrical connection between the plurality of cells 104a. The plurality of cells 104a are welded to the interconnector 106 to form the battery module 100a. The one or more interconnectors 106 are placed above the one or more battery module 100a and one or more sensing points 112 are provided on the module 100a to hold the one or more interconnectors 106 in place. In the present embodiment, the battery module casing 102 includes a first casing 102a, a top casing 102b, and a bottom casing 102c. The first casing 102a accommodates the cell holder 104 along with the plurality of cells 104a and supports the one or more sides of the battery module 100a. The top casing 102b covers the battery module 100a from a top portion of the battery module 100a. The bottom casing 102c provides a support to the one or more battery modules 100a. In an embodiment, the one or more casing 102 can be one of the aluminum casing. An output port 118 and a socket 120 are provided in the top casing 102b to bring out the connection to the outside of the battery pack 100.
[00039] Fig. 3(a) illustrates an exploded view of a battery module 100a of the battery pack, in accordance with an embodiment of the present disclosure.
[00040] Fig.3(b) exemplarily illustrates a top view of the battery module 100a showing the routing of one or more cord set 301 of a temperature sensing element 201 inside the battery pack 100. Fig.3(c) exemplarily illustrates a side view of the battery module 100a showing the routing of one or more cord set 301 of a temperature sensing element 201 outside of the battery pack 100. For the sake of understanding brevity, Fig.3(a), fig.3(b) and Fig.3(c) shall be discussed together. Fig.3(a) shows an exploded view of the of the battery module 100a. In the present embodiment, the plurality of cells 104a are held by the one or more cell holders 104. The cell holder 104 includes a bottom holder 104aa and a top holder 104ab. The bottom holder 104aa accommodates the plurality of cells 104a from a bottom portion of the plurality of cells 104a and have partitions provided between two horizontal rows. The top holder 104ab supports the plurality of cells 104a from a top portion of the plurality of cells 104a. The top holder 104ab also accommodates the one or more interconnectors 106 so as to form connections between the plurality of cells 104a with the one or more interconnectors 106. A base member 124 is attached at a side portion of the battery module 100a to provide as a connection interface between the one or more battery module 100a and a Battery Module Management System 125 (show in Fig. 2). However, the base member 124 can be positioned at any one of the sides of the battery module 100a, depending on the requirement and configuration of the battery pack 100. In the present embodiment, the base member 124 includes one or more electrical components (not shown) connected and placed on a portion of the base member 124. The base member 124 is sandwichedly disposed between the one or more interconnectors 106 and the Battery Module Management System 125 (shown in Fig. 2). In the present embodiment, the base member 124 can be a multilayer printed circuit board (PCB) acting as an insulation member between the one or more battery module 100a and the Battery Module Management System 125. However, any other material can be used exhibiting similar properties than the PCB. One side of the base member 124 is non conducting, and the non-conducting side of the base member 124 is faced towards the battery module 100a, acting as an insulator between the battery module 100a and the Battery Module Management System 125. The other side of the base member 124 is faced towards the Battery Module Management System 125 and accommodates one or more electrical connections.
[00041] In the present embodiment, the plurality of temperature sensing elements 201 are placed at six different locations in the battery pack 100. The plurality of temperature sensing elements 201 is disposed on the plurality of cells 104a. However, the number of cells 104a and the location/position of the plurality of temperature sensing elements 201 can be increased or decreased depending upon different factors. The different factors may include the total number of cells in the battery pack 100, configuration of the battery pack 100, dimension of the battery pack 100, no of drive cycle of the battery pack 100, maximum and minimum temperature of the battery pack 100, requirement of high or low currents from the pack 100, and the like. In the present embodiment, the temperature sensing element 201 is placed at six locations, namely, the first cell 302a is positioned adjacent to a top casing 102b of the battery pack, the second cell 302b is positioned at a centre of the battery pack, the third cell 302c is positioned on at least one corner of the battery pack, the fourth cell 302d is positioned alongside a first casing 102a of the battery pack 100 in a hotspot region of the battery pack 100, the fifth cell 302e positioned to sense a median temperature of the battery pack positioned in the centre of a quadrant (X’Y) disposed leftwards of YY’ Axis and upwards of XX’ Axis and the sixth cell 302f positioned in the centre of a quadrant (X’Y’) disposed leftwards of YY’ Axis and downwards of XX’ Axis when viewed from a top portion of the battery module 100a as shown in fig.3(b). However, the positions of the plurality of temperature sensing elements 201 can be changed based on the above-mentioned factors. In an embodiment, the first cell is located in a quadrant (XY) disposed rightwards of the YY’ Axis and upwards of the XX’ Axis. The third cell is configured to sense temperature of a coldest region of the battery pack. The fourth cell is located in the centre of a quadrant (XY) disposed rightwards of the YY’ Axis and upwards of the XX’ Axis.
[00042] The position of the plurality of temperature sensing element 201 ensures that the measurement of temperature is distributed evenly in the battery pack 100. The position/location of the plurality of temperature sensing elements 201 ensures the following: a) capturing of increase in battery pack 100 temperature due to internal reactions during riding of the vehicle, b) capturing of temperature efficiently will aid in designing an effective cooling system by which thermal runaway can be avoided, ensuring the safety of the rider of the vehicle, c) sensing temperature distribution in the battery pack 100 which helps to keep a check on battery operating window limits. Sensing abnormal increase in cell temperatures helps Battery Module Management System 125 to shut down or change the mode of working of the battery pack to prevent thermal runaway for safety of the user. High temperature sensing in the battery pack 100 can help us in designing optimised cooling system in order to get uniform distribution of temperature in pack thus avoiding hotspots. Temperature monitoring play’s crucial role in optimisation of parameters like state of charge (SOC) linked to performance, state of health (SOH) linked to battery lifetime and also linked to rider safety aspects. In the present embodiment, as shown in fig.3(b) and 3(c), the one or more cord set 301 with their respective wiring is shown. The wires are routed from the plurality of cells 502 out of the battery pack 100 from six positions.
[00043] Fig.3b exemplarily illustrates a top perspective view of the battery module 100a as per an embodiment of the present invention with the base member 124. The temperature sensing element 201 includes a one or more temperature sensor 601 (shown in fig.4b), and the one or more cord set 301. The base member 124 provides connection for the cord 301 of the temperature sensing element 201, so as to be connected with the Battery Module Management System 125 by means of plurality of temperature sensing elements coupler 401, provided on the sides of the base member 124. The one or more interconnectors 106 are connected to Battery Module Management System 125 by means of the base member 124. The base member 124 also includes the one or more voltage sensing points 112, where each of the one or more interconnectors 106 are getting attached. The one or more cord sets 301 from the battery pack 100 gets connected with the one or more temperature sensing couplers 401 provided on the base member 124. The base member 124 collects the signal from each interconnector 106 and the one or more temperature sensors 601 and transfers to the Battery Module Management System 125 by means of the cord set 301 and the plurality of temperature sensing couplers 401 provided on the base member 124. The Battery Module Management System 125 consists of a temperature sensing circuit (not shown) that gets electrically connected to the plurality of temperature sensing couplers 401 internally that monitors and measures the cell temperatures to control the battery module 100a operations.
[00044] Fig. 4(a) illustrates a temperature sensing element being disposed on a cell from the plurality of cells of the battery pack, in accordance with an embodiment of the present disclosure. In an embodiment, a plurality of temperature sensing elements is attached to the plurality of cells using one or more adhesive agents. Fig. 4 (a) illustrates the one or more cord set 301 and the temperature sensor 601 being connected to a cell of the plurality of cells within the battery pack. The plurality of temperature sensing elements comprises one or more temperature sensor 601, and a one or more cord set. In an embodiment, the one or more temperature sensor 601 is disposed on the plurality of cells. In an embodiment, the one or more temperature sensor 601 is connected to at one end of the one or more cord set and another end of the one or more cord set being connected to a base member.
[00045] Further, one or more adhesive agents being configured such that a first adhesive agent is configured to be pasted along a length of an exterior portion of the plurality of cells. The plurality of temperature sensing elements being sandwichedly mounted between the first adhesive agent (202a) and the second adhesive agent (202b). The second adhesive agent is configured to hold the plurality of temperature sensing elements on the exterior portion of the plurality of cells. The plurality of temperature sensing elements is attached to a centre position along the length of the plurality of cells of the battery pack.
[00046] Fig. 4(b) illustrates an exploded view explaining the disposition of the temperature sensing element being disposed on a cell from the plurality of cells of the battery pack, in accordance with an embodiment of the present disclosure. Fig. 4(b) exemplarily illustrates the side perspective of the plurality of cells 502 and the arrangement of attaching the temperature sensing element on to the plurality of cells 502, Fig. 4(c) shows an exploded view of the plurality of cells 502. The plurality of temperature sensing elements 201 are configured to be connected to the plurality of cells 502 such that the plurality of temperature sensing elements 201 are attached to the plurality of cells 502 using one or more adhesive agents 202. The one or more adhesive agents 202 are attached such that a first adhesive agent 202a is to be between the plurality of cells 502 and the plurality of temperature sensing element 201, and a second adhesive agent 202b configured to hold the plurality of temperature sensing elements 201 on outer side of the plurality of cells 502. The plurality of temperature sensing elements 201 are attached to a center position of the plurality of cells 502 of the battery pack 100. Such an arrangement is made to ensure that shorting is avoided and to hold the temperature sensing element 201 to the plurality of cells 502 securely positioned to avoid loss of contact. Such an arrangement with the first adhesive agent 202a along with the second adhesive agent 202b is used to ensure insulation on the plurality of cells 502 and therefore, avoid shorting of the plurality of temperature sensing element 201 with the plurality of cells 502.
[00047] In the present embodiment, a middle of the cell records high temperatures and is thus selected for the placement of one or more temperature sensors 601. Operating the battery pack 100 at different C rates (charging rate of the battery) and temperatures makes the pack 100 behave differently depending on the parameters like number of cells, design of the battery pack 100, test ambient, drive cycles, and the like. For example, operating at higher C rates and higher temperatures leads cell to reach high temperatures hence optimum number of one or more temperature sensors 601 and positioning and placement helps to achieve the aforementioned benefits. Selecting multiple cells ensures capturing of temperature evenly in the pack.
[00048] Fig. 4(c) illustrates various components comprising at least the temperature sensing element, the cord, the coupler, in accordance with an embodiment of the present disclosure. Fig 4(c) exemplarily illustrates the one or more cord set 301. One end of the cord set 301 is connected to the plurality of temperature sensing couplers 401, provided at the base member 124 using a coupler 602 provided at one end of the one or more cord set 301. In an embodiment, the plurality of temperature sensing couplers 401 may have a male connector and the coupler provided onto the one end may be a female connector. Another end of the one or more cord set 301 has the one or more temperature sensor 601 which is attached to the individual cell 104a. In the best embodiment, the optimum position for placing the second end with the one or more temperature sensor 601 of the one or more cord set 301 is at the centre of the individual cell 104a. In another embodiment the position for placing the second end of the one or more cord set 301 can be one of a top or a bottom portion of the cell 104a. The second end placed at the centre of the cell 104a provides the maximum temperature.
[00049] Fig. 5 illustrates a method performed by a Battery Module Management System of the battery pack, in accordance with an embodiment of the present disclosure.
[00050] The method starts at step 501 and proceeds to step 502. At step 502, the Battery Module Management System 125 is configured to obtain the temperature of the cell which is read by the temperature sensing element 201.
[00051] At step 503, the Battery Module Management System 125 configured to compare the received cell temperature with a first pre-determined temperature threshold value and a second pre-determined threshold value. These threshold values are determined through test data and experiments to arrive at the optimal threshold values.
[00052] At step 504, the Battery Module Management System 125 is configured to determine whether the received cell temperature is greater than the first pre-determined threshold value. If the received cell temperature is less than the first pre-determined threshold value, then the method returns to step 502 and obtains the cell temperature captured by the plurality of temperature sensing elements 201. If the received cell temperature is greater than the first pre-determined threshold value, then the method proceeds to step 505.
[00053] At step 505, the Battery Module Management System 125 is configured to determine whether the received cell temperature is greater than the second pre-determined threshold value. If the received cell temperature is less than the second pre-determined threshold value, the method proceeds to step 506. If the received cell temperature is greater than the second pre-determined threshold value, the method proceeds to step 507.
[00054] At step 506, the Battery Module Management System 125 is configured to initiate a switch from a power mode to an eco-mode of the Battery Pack 100. During the power mode, a significantly great amount of current is being drawn from the battery pack which may increase the temperature of the battery pack. Therefore, a switch to the eco-mode will limit the current being drawn from the battery pack, thereby limiting the increase in temperature of the battery pack.
[00055] At step 507, the Battery Module Management System 125 is configured to initiate a shutdown of the battery pack 100 to regulate the temperature of the battery pack 100 and to let the battery pack 100 cooldown ensuring that thermal runaway is avoided. Control passes to end step 508.
[00056] The present invention is advantageous to monitor overheating of the plurality of cells and prevent thermal runaway of the battery pack. Overheating of the plurality of cells in a battery pack leads to decrease in cell life and the performance efficiency of the battery pack. Temperature monitoring of the plurality of cells in a battery pack plays a crucial role in optimisation of parameters like state of charge (SoC) linked to performance, state of health (SoH) linked to battery lifetime. Moreover, such monitoring is beneficial to a user safety aspect.
[00057] The present invention will aid in increasing the performance of the battery pack, along with durability of the battery pack and safety of the user. The use of fewer components reduces the weight of the battery pack which promotes the performance of the vehicle and increases the serviceability of the battery pack and the vehicle. The serviceability of the battery pack is also increased as shorting of the plurality of cells in the battery pack is avoided due to the adhesive stickers.
[00058] The performance of the battery pack is also improved due to an efficient switch between power mode to eco-mode of the battery pack, and due to the shutdown of the battery pack in case the temperature of the plurality of cells exceeds a pre-determined threshold value. Additionally, the ease of assembly and handling of such battery pack is made easier and the cost of production of the battery pack is reduced considerably due to simple adhesives used to dispose temperature sensing elements on the plurality of cells of the battery pack.
[00059] The present invention optimizes the positioning of temperature sensing elements. Such optimum positioning of temperature sensing elements will sense temperature distribution in the battery pack which is critical to enable monitoring of the limits of the battery pack operating window, based on which an intelligent charging strategy is deduced. The present invention identifies the accurate temperature of the battery pack and strategically performs functions that will ensure the safety of the user.
[00060] The present invention in an embodiment has employed the use of six temperature sensing elements based on the dimensions of the battery pack. These temperature sensing elements have been disposed on plurality of cells selected strategically in the battery pack by considering aspects such as the areas of thermal hotspot, the coldest cells in the battery pack, and results of the safety tests conducted. A hotspot region is identified based on a pre-defined threshold temperature to determine areas of the battery pack that dissipate maximum temperature. Such strategic distribution of temperature sensing elements of the battery pack ensures that a median temperature of the battery pack is recorded while also reducing the number of components used for such operation. The positions of the cells are selected such that in any event of a nearest temperature sensing element is able to capture the hottest temperature in the vicinity of the plurality of cells, thus enabling the Battery Module Management System to take necessary actions for shutdown and warn the user.
[00061] The present invention employs the use of simple adhesives that can be applied along a length of an exterior portion of the plurality of cells, such that the plurality of temperature sensing elements is sandwichedly mounted between the first adhesive agent and the second adhesive agent. The second adhesive agent holds the plurality of temperature sensing elements on the exterior portion of the plurality of cells. The two simple adhesives not only eliminate the use of bulkier and costly adhesive techniques, but also these adhesives ensure insulation on of the plurality of cells, thus, avoiding the shorting of the temperature sensing elements with the plurality of cells.
[00062] The present invention strategically places the temperature sensing element to a centre position along the length of the plurality of cells of the battery pack, which was determined as a result of several experiments that were carried out by placing the temperature sensing elements at top (positive terminal), at bottom (negative terminal) and at centre. It was concluded that the maximum temperature of the cell is recorded at the centre, and therefore, the temperature sensing element is strategically placed at the centre to record an accurate and maximum temperature of the plurality of cells. Such accurate records will ensure that the increase in the battery pack temperature is captured at the earliest, ensuring that thermal runaway is avoided by taking prompt actions.
[00063] The present invention may be used in any multi wheeled Electric or Hybrid vehicles in which a lithium-ion cell battery pack is used.
[00064] The present invention makes use of the Battery Module Management System which optimises the performance of the battery pack by taking appropriate decisions based on the data received by the Battery Module Management System. The first pre-determined temperature threshold and the second pre-determined temperature threshold are advantageously calculated and selected based on test and experiments conducted.
[00065] In view of the above, the claimed limitations as discussed above are not routine, conventional, or well understood in the art, as the claimed limitations enable the above solutions to the existing problems in conventional technologies.
[00066] The present subject matter is described using an exemplary battery pack which is used in the vehicle, whereas the claimed subject matter can be used in any other type of application employing above-mentioned battery pack, with required changes and without deviating from the scope of invention. Further, it is intended that the disclosure and examples given herein be considered as exemplary only.
[00067] The terms “an embodiment”, “embodiment”, “embodiments”, “the embodiment”, “the embodiments”, “one or more embodiments”, “some embodiments”, and “one embodiment” mean “one or more (but not all) embodiments of the invention(s)” unless expressly specified otherwise. The terms “including”, “comprising”, “having” and variations thereof mean “including but not limited to”, unless expressly specified otherwise. The terms “a”, “an” and “the” mean “one or more”, unless expressly specified otherwise.
 
List of Reference numerals

100: Battery pack
100(a): Battery module
102: Battery pack casing
102(a): First casing
102(b): Top casing
102(c): Bottom casing
104: One or more cell holder
104(aa): Bottom holder
104(ab): Top holder
104(a): Plurality of cells
106: One or more interconnectors
108: One or more base member
112: One or more voltage sensing points
118: Output port
120: Socket
124: Base Member
125: Battery Module Management System
201: Plurality of temperature sensing element
202: One or more adhesive agents
202a: first adhesive agent
202b: second adhesive agent
301: One or more Cord set
302a: first cell
302b: second cell
302c: third cell
302d: fourth cell
302e: fifth cell
302f: sixth cell
302aa: First Temperature sensing element
302bb: Second Temperature sensing element
302cc: Third Temperature sensing element
302dd: Fourth Temperature sensing element
302ee: Fifth Temperature sensing element
302ff: Sixth Temperature sensing element
401: plurality of temperature sensing elements coupler on the base member
601: One or more temperature sensors
602: coupler of the cord set
, Claims:We claim:
1. A battery pack (100), the battery pack (100) comprising:
a plurality of cells (104a) comprising at least a first cell (302a), a second cell (302b), a third cell (302c), and a fourth cell (302d), wherein the first cell (302a), the second cell (302b), the third cell (302c), and the fourth cell (302d) being selected based on a total number of the plurality of cells disposed in the battery pack and one or more dimensions of the battery pack (100);
a plurality of temperature sensing elements (201) being connected to each of the first cell (302a), the second cell (302b), the third cell (302c), and the fourth cell (302d),
wherein the plurality of temperature sensing elements (201) comprises at least a first temperature sensing element (302aa), a second temperature sensing element (302bb), a third temperature sensing element (302cc), and a fourth temperature sensing element (302dd),
wherein the first temperature sensing element (302aa) being disposed on the first cell (302a), wherein the first cell (302a) being disposed adjacent to a battery pack top casing (102b),

wherein the second temperature sensing element (302bb) being disposed on the second cell (302b), wherein the second cell (302b) being disposed at a centre of the battery pack,

wherein the third temperature sensing element (302cc) being disposed on the third cell (302c), wherein the third cell (302c) being disposed on either corners of the battery pack (100) and,

wherein the fourth temperature sensing element (302dd) being disposed on the fourth cell (302d), wherein the fourth cell (302d) being identified based on one or more hotspot regions in the battery pack.

2. The battery pack (100) as claimed in claim 1, wherein the one or more hotspot regions being identified based on a pre-defined threshold temperature.

3. The battery pack (100) as claimed in claim 1,wherein the plurality of temperature sensing elements (201) being attached to the plurality of cells (104a) using one or more adhesive agents (202),

wherein the one or more adhesive agents (202) being configured such that,

a first adhesive agent (202a) configured to be pasted along a length of an exterior portion of the plurality of cells, wherein the plurality of temperature sensing elements (201) being sandwichedly mounted between the first adhesive agent (202a) and a second adhesive agent (202b), wherein the second adhesive agent (202b) being configured to hold the plurality of temperature sensing elements (201) on the exterior portion of the plurality of cells

wherein, the plurality of temperature sensing elements (201) being attached to a centre position along the length of the plurality of cells of the battery pack (100).

4. The battery pack (100) as claimed in claim 1, wherein the plurality of temperature sensing elements (201) comprises one or more temperature sensor (601), and a one or more cord set (301),
wherein the one or more temperature sensor (601) being disposed on the plurality of cells;

wherein the one or more temperature sensor (601) being connected to at one end of the one or more cord set and another end of the one or more cord set (301) being connected to a base member (124).

5. The battery pack (100) as claimed in claim 4, wherein the base member (124) being configured to have plurality of temperature sensing elements coupler (401), wherein the plurality of temperature sensing elements coupler (401) being configured to be connected with a Battery Module Management System (125) to receive one or more inputs from the battery pack (100).

6. The battery pack (100) as claimed in claim 5, wherein the Battery Module Management System (125) being configured to:

Obtain temperature captured by the plurality of temperature sensing elements (201);
Compare the received temperature with a first pre-determined temperature threshold value and a second pre-determined temperature threshold value; and
Initiate at least one of switch between a power mode to an eco-mode of the battery pack (100) and shut down of the battery pack (100) based on the comparison.
7. The battery pack (100) as claimed in claim 6, wherein when the temperature of the battery pack (100) is beyond the first pre-determined temperature threshold value then initiate switch between the power mode to the eco-mode of the battery pack (100), and when the temperature of the battery pack (100) goes beyond the second pre-determined temperature threshold value then initiate shut down of the battery pack (100).

8. The battery pack (100) as claimed in claim 1, wherein the plurality of cells being disposed in at least one of the quadrants formed by a YY’ Axis and a XX’ Axis.

9. The battery pack (100) as claimed in claim 8, wherein the first cell (302a) being located in a quadrant (XY) disposed rightwards of a YY’ Axis and upwards of a XX’ Axis.

10. The battery pack (100) as claimed in claim 8, wherein the third cell (302c) being configured to sense temperature of a coldest region of the battery pack (100).

11. The battery pack (100) as claimed in claim 8, wherein the fourth cell (302d) being located in the centre of a quadrant (XY) disposed rightwards of the YY’ Axis and upwards of the XX’ Axis.

12. The battery pack (100) as claimed in claim 8, wherein the plurality of cells (104a) comprises a fifth cell (302e), wherein the plurality of temperature sensing elements (201) comprises a fifth temperature sensing element (302ee) being disposed on the fifth cell (302e),
wherein the fifth cell (302e) being positioned in a centre of a quadrant (X’Y) and disposed leftwards of the YY’ Axis and upwards of the XX’ Axis,
wherein the fifth cell (302e) being configured to sense a median temperature of the battery pack (100).

13. The battery pack (100) as claimed in claim 8, wherein the plurality of cells (104a) comprises a sixth cell (302f), wherein the plurality of temperature sensing elements (201) comprises a sixth temperature sensing element (302ff) being disposed on the sixth cell (302f),
wherein the sixth cell (302f) being positioned in the centre of a quadrant (X’Y’) disposed leftwards of the YY’ Axis and downwards of the XX’ Axis.