Description:TECHNICAL FIELD
[0001] The present subject matter generally relates to an energy storage device. The present application is a patent of addition with respect to the patent application number 201941024302.
BACKGROUND
[0002] Typically, lead-acid batteries are used as a cheap power source in different products e.g. vehicles, power tools, fork lifts, etc. In a vehicle, lead acid batteries are typically used for powering a starter motor of the internal combustion engine, or a motor etc. However, their low energy density, and their inability to reject heat adequately, makes them an impractical power source especially for electric vehicles. Particularly, electric vehicles using lead acid batteries have a short range. In addition, electric vehicles using lead-acid batteries have sluggish acceleration, poor tolerance to deep discharge, and low battery lifetime.
[0003] As a result of the disadvantages associated with lead acid batteries, energy storage devices containing lithium-ion batteries have become increasingly popular in many products, including in various commercial electronic devices, owing to their ability to be recharged, weightlessness and high energy density. However, storing and operating the energy storage devices containing lithium-ion batteries at an optimal operating temperature is very important to allow the device to retain charge for an extended period of time and allow faster charging rates.
[0004] Typically, an energy storage device such as a lithium-ion battery pack comprises a battery unit composed of one or more energy storage cells electrically connected with one another in either series or parallel connection, or a combination of series connections and parallel connections. Typically, the battery pack comprises of one or more holder structures for holding one or more energy storage cells.
[0005] During operative conditions of the battery pack, the current flows through the battery unit(s) to power the device or product. As current is drawn off the battery unit(s), heat is generated within the battery pack. Also, during charging of the battery pack, heat is likewise accumulated during the charging process. The heat generated during discharge of the battery unit(s) as well as charging of the battery unit(s), leads to increased temperatures causing a severe effect on the life expectancy and performance of the battery unit(s). Thus, when one or more energy storage cell goes into thermal runaway, either through violation of safe temperature limit, manufacturing process induced cell short circuit, over charge or depending on the type of material used for manufacturing the holder structure for the cells, the amount of energy released may cause adjacent energy storage cells to also go into thermal runaway, this chain reaction destroys the battery pack. This can lead to safety risk and potential fatal accident for the user of the product which is highly undesirable.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] The detailed description is described with reference to an embodiment for a two-wheeled vehicle as a product, accompanied by corresponding figures. The same numbers are used throughout the drawings to reference like features and components.
[0007] Fig.1 is a side view of a saddle-type vehicle including an energy storage device in accordance with an embodiment of the present invention.
[0008] Fig.2 is a perspective view of an energy storage device as per an embodiment of the present invention.
[0009] Fig.3 is an exploded view of the energy storage device as per an embodiment of the present invention.
[00010] Fig.4 is a cross sectional view depicting a portion of a cell assembly of the energy storage device comprising empty space as per an embodiment of the present invention.
[00011] Fig. 5 is a cross sectional view of the energy storage device depicting at least a portion of the cell assembly without empty space as per an embodiment of the present invention.
[00012] Fig. 6 is a flowchart depicting method of manufacturing the energy storage device as per an embodiment of the present invention.

DETAILED DESCRIPTION
[00013] Typically, an energy storage device such as a battery pack comprises a cell assembly comprised of at least one holder structure configured to hold a plurality of energy storage cells therein. Typically, the energy storage cells are placed in the at least one cell holder and the same is inserted into an outer casing made up of a rigid material such as a metal of high conductivity. Generally, a major portion of the at least one cell holder is placed apart from the outer casing with a minimum air gap of 5mm. In such an energy storage device, cooling structures in the form of fins are formed in at least a portion of sidewalls of the outer casing. The heat generated during charging and discharging process of the one or more the energy storage cells is effectively dissipated through the cooling structures. Often the heat generated during charging and discharging process of the energy storage cells, especially Li ion cells is so high that it leads to melting of electrical components within the holder structure, resulting in electric short circuit within the battery pack. While providing an aluminum outer casing for the energy storage cells aids in dissipating heat from the energy storage cells, however, the presence of air gap between the cell assembly comprising the energy storage cells and the aluminum outer casing hinders efficient dissipation of heat to the aluminum casing as air is a bad thermal conductor.
[00014] In a known structure for supporting the energy storage cells of the energy storage device, the at least one holder structure is provided with a phase change material (PCM). In the known structure, enmoulded PCM blocks are used for absorbing heat from the energy storage cells. As the latent heat of fusion of the phase change material (PCM) is high, it absorbs significant amount of heat without much rise in temperature. During charging and discharging of the energy storage device, the phase change material absorbs heat generated by the energy storage cells and hence changes its state from solid to liquid. However, due to its low thermal conductivity and poor heat dissipating properties, the use of PCM alone proves to be insufficient for effective heat dissipation from the energy storage cells and there exists a need to improve cooling rate of the battery pack. Moreover, when PCM is filled completely within the outer casing and around the cell assembly it leads to a substantial increase in weight of the energy storage device, and also results in substantial increase in cost of the energy storage device which is undesirable. An increase in weight of the energy storage device/battery pack leads to significant increase in weight of the device or product. This is especially critical for portable devices and products which require mobility e.g., electric vehicles where an energy storage device comprising a huge array of Li ion cells is used to power the vehicle.
[00015] Further, with use of enmoulded PCM blocks within the battery packs, the chances for the air gap between the outer casing and the cell holder assembly to increase is higher, as it is likely that a variance in shape/profile of the outer casing with respect to the shape/profile of the previously enmoulded block of PCM exists. In such cases the conduction of heat from the enmoulded PCM block to the outer casing will be very poor. Further, use of enmoulded PCM blocks entails greater cost of manufacturing and greater complexity in manufacturing. Also, in extreme conditions, the PCM melts causing leakage of PCM from the outer casing.
[00016] The present application is a patent of addition of the patent application number 201941024302. Henceforth patent application number 201941024302 is referred as “Main application” for the purpose of brevity.
[00017] The “Main application” discloses about an energy storage device in which efficient cooling of energy storage cells is achieved while ensuring low cost of manufacturing and ease of manufacturing of the energy storage device. Further, the “Main application” discloses about the energy storage device having a cell assembly comprising a plurality of energy storage cells placed in at least one cell holder structure, and the cells are thermally connected to one another by a Phase Change Material (PCM). The cell assembly is enclosed in an outer casing, which is lined with a highly conductive thermal foam. The PCM thermally connecting the energy storage cells is maintained in thermal contact with the conductive foam material. The method of manufacturing the energy storage device involves a pre-step of lining the outer casing with the conductive thermal foam, followed by the installation of the cell assembly comprising the energy storage cells. The empty spaces between the cell assembly and the outer casing lined with the conductive thermal foam are filled with the PCM, which is heated to a temperature above 50°C, and the PCM is allowed to solidify and attain an ambient temperature of 30-35°C. Finally, the outer casing is closed with an end cover. The “Main application” provides a highly efficient energy storage device with minimal weight gain due to PCM filling significant internal volume of the outer casing.
[00018] However, there are still chances that due to ineffective heat dissipation, or failure of effective heat dissipation thermal runaway of the energy storage device may occur. Thereby, if the user is not timely alerted about the heating of the energy storage device, several problems can occur, including reduced battery lifespan, safety hazards, costly repairs of the overall energy storage device along with the vehicle, and reduced battery life span.
[00019] The overheating of the energy storage device can substantially reduce the overall lifespan of the energy storage device, leading to its premature failure. If the user is not timely alerted about the battery heating, they may continue to use the vehicle for a long period of time, which can cause further damage to the energy storage device and other neighboring components. Further overheated energy storage devices can be a safety hazard, as they can potentially explode or catch fire. If the user is not timely alerted about the overheating, they may fail to take the necessary precautions to avoid any potential safety hazards. Further, if the energy storage device and other components are damaged due to overheating, it can result in costly repairs or replacements. If the user is not alerted about the overheating, they may continue to use the vehicle, which can cause further damage and increase repair costs. Moreover, if the energy storage device overheats and fails while the user is driving, it can cause the vehicle to break down, leading to inconvenience and potential safety hazards for the user. Thereby, it is important to monitor the temperature of the energy storage device and timely alert the user to take necessary safety precautions.
[00020] The present application discloses a subject matter that has been devised in view of the above circumstances as well as solving other problems of the known art.
[00021] The present subject matter in an embodiment, discloses an energy storage device comprising a cell assembly. The cell assembly comprises at least one cell holder structure and a plurality of energy storage cells held in the holder structure and being thermally connected by a phase change material. Further, the energy storage device comprises of an outer casing containing the cell assembly. The outer casing is lined with a highly conductive thermal foam, and the phase change material fill empty spaces within the outer casing of the energy storage device. The energy storage device is configured to alert a user by using at least one alerting means, upon detection of change of state of at least one of the highly conductive thermal foam and the phase change material.
[00022] For example, change of state of the highly conductive thermal foam may include conversion of the highly conductive thermal foam from foamy state to a liquid state, due to overheating of the energy storage device. Another example may include conversion of state of the phase change material from solid state to a liquid state, due to overheating of the energy storage device.
[00023] As per another aspect of the present embodiment, the detection of the change of state of at least one of the highly conductive thermal foam and the phase change material, being detected by using at least one of, one or more temperature sensors, one or more voltage sensors, one or more pressure sensors, and one or more colour changing material.
[00024] As per another aspect of the present embodiment, at least one of, the one or more temperature sensors, the one or more voltage sensors, the one or more pressure sensors, and the one or more colour changing material, being configured to be embedded within the energy storage device in close proximity of the at least one of the highly conductive thermal foam and the phase change material. Because of being embedded within the energy storage device and being in close proximity of the of the at least one of the highly conductive thermal foam and the phase change material; the at least one of, the one or more temperature sensors, the one or more voltage sensors, the one or more pressure sensors, and the one or more colour changing material are capable of detecting the change in state of the at least one of the highly conductive thermal foam and the phase change material; and thereby capable of relaying the information to the at least one alerting means, which can be used to alert the user about overheating of the energy storage device.
[00025] As per another aspect of the present embodiment, the alerting means through which the user can be alerted about the overheating of the energy storage device may include one of a visual alerting means, audible alerting means, mobile alerting means, on-board diagnostic alerting means.
[00026] Exemplary embodiments detailing features of the energy storage device configured for improved cooling rate of the plurality of energy storage cells contained therein in accordance with the present invention will be described hereunder. The embodiments described herein apply to a vehicle having an energy storage device such as a battery pack and powered by either a motor alone or by both internal combustion engine, and the motor. Also, although the embodiments have been exemplified for a two-wheeled saddle-type vehicle, the present invention is applicable for all types of portable devices as well as products with mobility having an energy storage device and powered by either a motor alone or by both the internal combustion engine, and the motor. The energy storage device/battery pack may be composed of Li ion cells and the like.
[00027] With reference to Fig.1 a description is made of a vehicle 100 which is a hybrid two-wheeled saddle-type vehicle in accordance with an embodiment of the present invention. FIG.1 is a side view the vehicle 100. The vehicle 100 illustrated, has a step-through type frame assembly. The step-through type frame assembly includes a steering tube 101, a main tube 102 and a pair of side tubes 103. Particularly, the main tube 102 extends downwards from a rear portion of the steering tube 101 and then extends rearwards in an inclined manner. Further, the pair of side tubes 103 extends inclinedly upwardly from the main tube 102. Thus, the frame assembly extends from a front portion to a rear portion of the vehicle.
[00028] The vehicle 100 further includes a plurality of body panels for covering the frame assembly and is mounted thereto. In the present embodiment the plurality of panels includes a front panel 104, a leg shield 105, an under-seat covers 106, and a left and a right, side panel 107. Further, a glove box may be mounted to the leg shield 105.
[00029] In a step through space formed between the leg shield 105 and the under seat cover 106, a floorboard 108 is provided. Further, a seat assembly 110 is disposed above the under-seat cover 106 and is mounted to the pair of side tubes 103. A utility box (not shown) is disposed below the seat assembly 110. A fuel tank (not shown) is positioned at one end of the utility box. A rear fender 111 for covering at least a portion of a rear wheel 112 is positioned below the utility box.
[00030] One or more suspension(s)/shock absorbers 120 are provided in a rear portion of the vehicle 100 for a comfortable ride. Further the vehicle 100 comprises of a plurality of electrical and electronic components including a headlight 115, a taillight (not shown), a transistor-controlled ignition (TCI) unit (not shown), a starter motor (not shown) and the like. A display unit (not shown) is provided on a handlebar 109 to display various operating modes, power flow pattern and warning signals or alert signals. The rear-view mirrors 113 are mounted on the right and left sides of the handlebar 109. The vehicle 100 is also provided with hazard lamps (not shown). Further the vehicle 100 also includes an arc fault detection indicator (not shown) near the display unit of the vehicle 100. In an embodiment, the indicator glows on detection of any arc fault in the vehicle 100 indicating that the vehicle 100 would be disabled shortly.
[00031] An internal combustion engine 135, hereinafter “engine”, is arranged behind the floorboard 108 and supported between the pair of side tubes 103. Particularly, the internal combustion engine 135 is supported by a swing arm 136. The swing arm 136 is attached to a lower portion of the main tube 102 by means of a toggle link (not shown). The other end of the swing arm 136 holds the rear wheel 112. The rear wheel 112 and the swing arm 136 are connected to the pair of side tubes 103 by means of one or more shock absorbers 120 provided on either side of the vehicle 100.
[00032] The vehicle 100 further includes a traction motor 150 mounted on a hub of the rear wheel 112. The traction motor 150 is powered by an energy storage device 200 (shown in Fig.2) disposed in a rear portion of the vehicle. However, in another embodiment, the energy storage device 200 may be disposed in a front portion of the vehicle. The energy storage device 200 also powers all the electrical components of the vehicle 100. A motor control unit (MCU) (not shown) is also provided to control various vehicle operative modes.
[00033] The vehicle 100 is configured to be propelled either by the engine 135 alone or by the traction motor 150 alone or by both engine 135 and traction motor 150 simultaneously. At zero vehicle speed, a rider can select any of the following four operating drive modes with the help of a mode switch. The four operating drive modes of the vehicle 100 are: (a) a sole engine mode where engine 135 alone powers the vehicle (b) a sole motor mode where the traction motor 150 alone powers the vehicle (c) a hybrid power mode wherein the engine 135 and the traction motor 150 together power the vehicle 100 (d) a hybrid economy mode wherein only the engine 135 or only the traction motor 150 or both power the vehicle depending on the vehicle operating conditions.
[00034] In other words, the rear wheel 112 of the vehicle is driven by either the engine 135 alone or by the motor 150 alone or by both the engine 135 and the motor 150 simultaneously. Particularly, power from the engine 135 to the rear wheel 112 is transmitted by a transmission assembly including a drive system (not shown) as per an embodiment of the present invention. However, when the traction motor 150 drives, power from the motor 150 is directly transmitted to the rear wheel 112. In the present embodiment, the traction motor 150 is covered by a motor shroud (not shown) from at least one side.
[00035] Referring to Fig.2, description is made of a schematic representation of the energy storage device 200 of the vehicle 100 as per an embodiment of the present invention. Fig.2 is a perspective view of an energy storage device 200, as per an embodiment of the present invention. As per an embodiment and as may be seen in Fig.2 the energy storage device 200 configured to supply power to the traction motor 150 and other electrical components of the vehicle 100 comprises an outer casing 201 to accommodate a cell assembly 202 (shown in Fig.3) comprising a plurality of energy storage cells 202b (shown in Fig.3) therein. The outer casing 201 thus encompassing the cell assembly 202 is covered at its left and right ends by a pair of end cover members 201L 201R. In another embodiment, the energy storage device 200 is configured to power the vehicle. Particularly, multiple number of above-described energy storage devices stacked together may be used to power the vehicle. In the present embodiment too, multiple numbers of above-described energy storage device are stacked together for powering the traction motor and other electrical components of the vehicle 100.
[00036] Fig.3 is an exploded view of the energy storage device 200 as per one embodiment of the present invention. In one embodiment and as may be seen in Fig.3, the energy storage device 200 comprises the outer casing 201 for accommodating a cell assembly 202. The cell assembly comprises at least one holder structure 202a for holding the plurality of energy storage cells 202b. The energy storage cells 202b are arranged in slots formed in the at least one cell holder structure 202a. The cells 202b thus arranged are electrically connected by a plurality of interconnect members 202c disposed over each row of the cells 202b and permanently attached to at least a portion of the at least one holder structure 202a. To one portion of the cell assembly 202, a control unit 203 is provided which aids in controlling operation of the energy storage device 200. The cell assembly 202 thus comprising the plurality of energy storage cells 202b and attached to the control unit 203 is inserted into the outer casing 201 of the energy storage device 200. In an embodiment, the outer casing 201 is made of rigid highly conductive material such as metal aluminium. Further, the outer casing 201 is provided with the pair of end cover members 201L, 201R for enclosing the cell assembly 202 within the outer casing 201.
[00037] Fig.4 illustrates a cross sectional view of a portion of the cell assembly 202 taken along a line A-A in Fig.3. The cell assembly 202 as may be seen includes a number of empty spaces including a first set of empty spaces 202d and a second set of empty spaces 202e between the plurality of energy storage cells 202b and between the plurality of cells 202b and at least a portion of the holder structure 202a respectively. In other words, typically air gap exists between each of the cells of the plurality of energy storage cells 202b and between the cells 202b and at least a portion of the cell holder structure 201a. Further empty space/air gap is also present between the cell assembly 202 and an inner surface of the outer casing 201, in an assembled condition of the cell assembly 202 inside the outer casing 201.
[00038] During operative conditions of the energy storage device 200, the current flows through the cells 202b to power the vehicle 100 or to power different components of the vehicle 100. As current is drawn off the cells 202b, the heat is generated within the cell assembly 202. Presence of air gap/ empty spaces (202d,202e) between the cells 202b and between the cells 202b and at least a portion of the cell holder structure 201a affects the dissipation of heat from the cells 202b to the outer casing 201 (shown in Fig.3), thereby leading to heat buildup within the cell assembly 202 and within the outer casing 201. Heat buildup within the cell assembly 202 can lead to thermal runaway of cells, and finally lead to destruction of the energy storage device 200. In order to prevent thermal runaway of the cells 202b and to improve rate of cooling of the cells 202b, the present subject matter provides the energy storage device 200 as per one embodiment.
[00039] Fig.5 illustrates a flowchart 300 depicting steps involved in method of manufacturing the energy storage device 200. A first step of the method depicted at block 301 involves lining the outer casing with a highly conductive thermal foam 204 (shown in Fig.6) for example silicon foam. Lining the outer casing 201 with a highly conductive thermal foam 204 in a same profile as that of the cell assembly 202 ensures that empty space/air gap between the outer casing 201 and the cell assembly 202 is minimized. As per one embodiment, a highly conductive adhesive thermal foam having specific gravity <0.25 is used to line the inner surface of the outer casing 201.
[00040] For example, in an embodiment the thermal foam 204 lining the inner surface of the outer casing 201 has a thickness in the range of 2mm-5mm. Further, a second step depicted at block 302 involves installing/inserting the cell assembly 202 within the outer casing 201 previously lined with the thermal foam 204 and closing one end of the outer casing 201 with one end cover member 201R of the pair of end cover members. A third step of the method depicted at block 303 involves pouring a Phase Change Material 205 (shown in Fig.6) having phase transition temperature in the range of 50-55℃ and having specific gravity > 1 into the outer casing 201 lined with the thermal foam 204 and containing the cell assembly 202 therein. In other words, a phase change material previously heated to 50-55℃ is poured into the outer casing previously lined with the thermal foam. As per an embodiment, the volume of PCM 205 to be poured into the outer casing to fill empty spaces in the cell assembly 202 is determined based on pre-calculated volume of empty spaces i.e. first set of empty spaces 202d (shown in Fig.4) and second set of empty spaces 202e (shown in Fig.4) in the cell assembly 202.
[00041] A fourth step of the method involves allowing a predetermined curing time for the PCM 205 filled between the cells 202b of the cell assembly 202 and between the cells 202b and at least one holder structure 202a of the cell assembly 202 to solidify and attain an ambient temperature of 30-35°C (see block 304). Typically, as per an embodiment a curing time of 1.5-2 hours is allowed for the PCM 205 to solidify. Further, a fifth step of the method and as depicted in block 305 involves placing an end cover 201L of the pair of end cover members to enclose the cell assembly 202 filled with PCM 205 within the outer casing 201 lined with the thermal foam 204.
[00042] The provision of the thermal foam 204 also helps in preventing leakage of PCM 205 from the outer casing 201 in cases when PCM 205 melts. As per an embodiment of the present subject matter, upon detection of change of state of at least one of the highly conductive thermal foam 204 and the phase change material 205, the energy storage device 200 is configured to alert a user by at least one alerting means 401 (shown in Fig. 6). For example the user is alerted upon melting of PCM 205 after getting overheating due to the excess heat produced by the energy storage device 200. Herein the detection of change of state of at least one of the highly conductive thermal foam 204 and the phase change material 205, is carried by at least one detecting means 400. The at least one detecting means 400 include at least one of one or more temperature sensors, one or more voltage sensors, one or more pressure sensors, and one or more colour changing material.
[00043] In an embodiment of the present subject matter, the at least one detecting means 400 is configured to be embedded within the energy storage device 200 in close proximity of at least one of the highly conductive thermal foam 204 and the PCM 205.
[00044] In an embodiment, the at least one detecting means 400 detects the change of state of at least one of the highly conductive thermal foam 204 and the phase change material 205, and conveys the information to the control unit 203. The control unit 203 conveys the information to the user by one or more alerting means 401.
[00045] Fig.6 illustrates a cross sectional view of an energy storage device prepared/manufactured as per the steps described in Fig.5. As may be seen the PCM 205 fills the first set of empty spaces 202d between the cells 202b and fills the second set of empty spaces 202e between the cells 202b and at least a portion of the cell holder structure 202a. Thus, the PCM 205 thermally connects the plurality of energy storage cells 202b in the cell assembly 202. Particularly, as per an embodiment, a ratio of filling of empty spaces within the outer casing 201 by the PCM 205 and the thermal foam 204 is in range of 85% to 15% to achieve best thermal dissipation efficiency. In other words, while majority of air gap within the cell assembly is filled by the PCM 205, air gap between outer casing 201 and the cell assembly 202 is filled by the thermal foam 204. Thus, as PCM 205 does not completely fill the volume of empty space in the cell assembly 202 and between the cell assembly 202 and the outer casing 201, it is ensured that weight of the energy storage device 200 does not go up significantly. Moreover, since the highly conductive thermal foam 204 is used to line the outer casing 201, it is ensured that heat absorbed by the PCM 205 is effectively conducted to the outer casing 201 by the foam 204, thereby ensuring improved cooling rate of the plurality of energy storage cells 202b. Also, since PCM 205 is poured in liquid form over the cell assembly 202 and is allowed to subsequently get solidified, ease of manufacturing of the energy storage device 200 is ensured in comparison to devices where enmoulded/machined PCM blocks are used in the cell assembly. Thus, cost of moulding/machining of PCM blocks is avoided and low cost of manufacturing of the energy storage device 200 is ensured. Moreover, since PCM 205 is poured into the outer casing 201 rather inserting cell assembly 202 comprising pre-moulded/pre-machined into the outer casing 201, it is ensured that problem of variance in profiles of the outer casing and the pre-moulded/machined PCM blocks is avoided. This, in turn aids in ensuring that there is minimal air gap between the cell assembly 202 and the outer casing 201, thereby ensuring effective heat transfer/conductivity from the PCM 205 to the outer casing of the energy storage device 200. Thus, a hybrid heat dissipation system is configured for an energy storage device 200 to improve its thermal dissipation efficiency thereby enhancing performance as well as durability of the energy storage device 200.
[00046] As per an embodiment of the present subject matter, upon detection of change of state of at least one of the highly conductive thermal foam 204 and the phase change material 205, the energy storage device 200 is configured to alert a user by at least one alerting means 401 (shown in Fig. 6). For example, the user is alerted upon melting of PCM 205 after getting overheating due to the excess heat produced by the energy storage device 200. Herein the detection of change of change of state of at least one of the highly conductive thermal foam 204 and the phase change material 205, is carried by at least one detecting means 400. The at least one detecting means 400 include at least one of one or more temperature sensors, one or more voltage sensors, one or more pressure sensors, and one or more colour changing material.
[00047] In an embodiment of the present subject matter, the at least one detecting means 400 is configured to be embedded within the energy storage device 200 in close proximity of at least one of the highly conductive thermal foam 204 and the PCM 205. In another embodiment, the at least one detecting means 400 is embedded within at least one outer casing 201 of the energy storage device 200, such that at any point of time, the at least one detecting means 400 is in thermal contact with at least one of the highly conductive thermal foam 204 and the PCM 205.
[00048] In one embodiment, at least one detecting means 400 includes at least one temperature sensor. The at least one temperature sensor can be embedded within the energy storage device 200 to detect changes in temperature. When the temperature of the phase change material 205 reaches a certain threshold, it can trigger an alert to the user. Similarly, at least one detecting means 400 includes at least one voltage sensors. The at least one voltage sensors can be used to monitor the voltage of the energy storage device 200. When the state of the phase change material 205 changes, it can affect the voltage of the energy storage device 200. If the voltage drops or rises beyond a certain threshold, it can trigger an alert to the user.
[00049] Similarly, in another embodiment, at least one detecting means 400 includes at least one pressure sensor. The at least one pressure sensor can be used to detect changes in pressure within the energy storage device 200. When the phase change material 205 changes state, it can cause a change in pressure. If the pressure goes beyond a certain threshold, it can trigger an alert to the user. Similarly, at least one detecting means 400 includes at least one color-changing materials. The at least one color-changing materials can be used to detect changes in the state of the phase change material 205. For example, a material that changes color when it melts could be placed within the energy storage device 200. When the phase change material 205 melts, it can trigger a change in color, which can then be detected by the user. Once the change in state of the phase change material 205 has been detected through any of the above means, the information can be conveyed to the user through various means, such as visual indicators, audible alarms, or notifications on a connected device.
[00050] In another embodiment, the at least one alerting means include at least one of a visual alerting means, an audible alerting means, a mobile alerting means, and an on-board diagnostic alerting means. In one embodiment, the visual alerting means includes a display device of the vehicle 100. As per an aspect, the vehicle’s 100 display device or the dashboard can display a warning light or message to alert the user upon the energy storage device 200 starts getting overheated. As per another embodiment, the audible alerting means includes an audible alarm or chime that can also be used to alert the driver when the energy storage device 200 upon the energy storage device 200 starts getting overheated. This is useful when the user is not looking at the dashboard or the display system of the vehicle 100.
[00051] Further, in another embodiment, the user can be alerted by using mobile alerting means. In today’s era many modern vehicles 100 are equipped with a mobile application that allows the user to monitor the energy storage device 200 remotely. The mobile applications can send alerts to the user's smartphone whenever the energy storage device’s 200 temperature reaches a certain threshold, as detected by the detecting means 400.
[00052] In another embodiment, the on-board diagnostic alerting means can be configured to monitor the energy storage device’s 200 temperature and send alerts to the user or a service center on need basis.
[00053] Upon getting notified about the overheating of the energy storage device 200, the user can take some safeguard measures. Some of the safeguarding measures may include stopping the vehicle 100 in a safe location and switch off the engine of the vehicle 100. This will help to prevent further damage to the energy storage device 200 and neighboring other components.
[00054] Another safeguarding measures may include allowing the energy storage device 200 to cool down, after stopping the vehicle 100. The user should allow the energy storage device 200 to cool down before attempting to use the vehicle 100 again. This can take anywhere from a few minutes to several hours, depending on how hot the energy storage device 200 is.
[00055] Another safeguarding measures may include checking the energy storage device 200 connections. The user should also check the energy storage device 200 connections to ensure they are tight and secure. Loose connections can cause the energy storage device 200 to overheat, so tightening them can help to prevent further problems.
[00056] Another safeguarding measures may include avoiding overusing of electronic devices in the vehicle 100, as this can cause the energy storage device 200 to overheat. Thereby upon being alerted turning off of the unnecessary devices or reducing their usage can help to prevent overheating of the energy storage device 200.
[00057] In worst case scenario, as a safeguarding measure, post being alerted about overheating of the energy storage device 200, the user can seek professional assistance from a qualified mechanic or service center.
[00058] The present subject matter described herein thus advantageously provides an economical energy storage device 200 with improved rate of cooling of energy storage cells along with an alerting means which would enable alerting the user upon the energy storage device 200 getting overheated, thereby ensuring improved performance of the energy storage device. Improvements and modifications may be incorporated herein without deviating from the scope of the invention.

LIST OF REFERENCE NUMERALS

100: Vehicle
101: Steering tube
102: Main tube
103: Side tubes
104: Front panel
105: Leg shield
106: Under-seat cover
107: Side panel
108: Floorboard
109: Handlebar
110: Seat assembly
111: Rear fender
112: Rear wheel
113: Rear-view mirrors
115: Headlight
120: Shock absorbers
135: Internal combustion engine
136: Swing arm
150: Traction motor
200: Energy storage device
201: Outer casing
201L: End cover
201R: End cover member
202: Cell assembly
202a: Holder structure
202b: Energy storage cells
202c: Interconnect members
202d: A first set of empty spaces.
202e: A second set of empty spaces
203: Control unit
204: Thermal foam
205: Phase change material
300: Flowchart
301: Block involving lining the outer casing with a highly conductive thermal foam
302: Block involving installing/inserting the cell assembly within the outer casing
303: Block involving pouring a Phase Change Material into the outer casing
304: Block involving allowing a predetermined curing time for the PCM to solidify
305: Block involving placing an end cover of the pair of end cover members
400: Detecting means
401: Alerting means

, Claims:We Claim:
1. An energy storage device (200) comprising:
a cell assembly (202) comprising at least one cell holder structure (202a) and a plurality of energy storage cells (202b) held in said holder structure (202a) and being thermally connected by a phase change material (205),
an outer casing (201) containing said cell assembly (202);
wherein said outer casing (201) being lined with a highly conductive thermal foam (204), and said phase change material (205) fill empty spaces within said outer casing (201) of said energy storage device (200), and
wherein said energy storage device (200) being configured to alert a user by at least one alerting means, upon detection of change of state of at least one of said highly conductive thermal foam (204) and said phase change material (205).
2. The energy storage device (200) as claimed in claim 1, wherein said detection of change of state of at least one of said highly conductive thermal foam (204) and said phase change material (205), being detected by using at least one detecting means (400).
3. The energy storage device (200) as claimed in claim 1, wherein said at least one detecting means (400) include at least one of one or more temperature sensors, one or more voltage sensors, one or more pressure sensors, and one or more colour changing material.
4. The energy storage device (200) as claimed in claim 2, wherein said detecting means (400), being configured to be embedded within said energy storage device (200) in close proximity of at least one of said highly conductive thermal foam (204) and said phase change material (205).
5. The energy storage device (200) as claimed in claim 2, wherein said at least one detecting means (400), being configured to be embedded within at least one outer casing (201) of said energy storage device (200), wherein said at least one detecting means (400) being in thermal contact with at least one of said highly conductive thermal foam (204) and said phase change material (205).
6. The energy storage device (200) as claimed in claim 1, wherein said at least one alerting means include at least one of a visual alerting means, an audible alerting means, a mobile alerting means, and an on-board diagnostic alerting means.
7. The energy storage device (200) as claimed in claim 4, wherein said at least one of a visual alerting means includes a display device of a vehicle (100).
8. The energy storage device (200) as claimed in claim 1, wherein the change in state of said phase change material (205) occurs upon said phase change material (205) being heated more than an ambient temperature of 30-35°C.
9. The energy storage device (200) as claimed in claim 1, wherein said highly conductive thermal foam (204) having a specific gravity less than specific gravity of said phase change material (205).
10. The energy storage device (200) as claimed in claim 1, wherein said thermal foam having a specific gravity less than 0.25.
11. The energy storage device (200) as claimed in claim 1, wherein said highly conductive thermal foam (204) and said phase change material (205) fill empty spaces within said outer casing (201) in a ratio of 15% to 85%.
12. The energy storage device (200) as claimed in claim 1, wherein said highly conductive thermal foam (204) being designed to be pasted on an inner surface of said outer casing (201) lining of said cell assembly (202).
13. The energy storage device (200) as claimed in claim 1, wherein said phase change material (205) having at least one of a phase change temperature in the range of 50-55℃ and specific gravity greater than 1.
14. The energy storage device (200) as claimed in claim 1, wherein said highly conductive foam (204) being elastically biased against said outer casing (201) and at least one of said plurality of energy storage cells (202b), by means of a press fit configuration.
15. The energy storage device (200) as claimed in claim 13, wherein said press fit configuration being achieved in the volumetric range up to maximum 10% of the volume of said highly conductive foam (204).
16. The energy storage device (200) as claimed in claim 1, wherein said highly conductive thermal foam (204) having a thickness in the range of 2mm-5mm.
17. The energy storage device (200) as claimed in claim 1, wherein said user being alerted upon melting of said phase change material (205), wherein said phase change material (205) being melted upon said phase change material (205) getting overheating due to excess heat produced by said energy storage device (200).
18. The energy storage device (200) as claimed in claim 1, wherein said user being alerted upon temperature of said phase change material (205) reaches a pre-determined threshold.
19. The energy storage device (200) as claimed in claim 1, wherein said user being alerted upon one of a dropping of voltage and rising of said voltage of said energy storage device (200) being beyond a pre-determined threshold.
The energy storage device (200) as claimed in claim 1, wherein said user being alerted upon pressure of said energy storage device (200) being beyond a a pre-determined threshold.