Description:FIELD OF THE INVENTION
[0001] The present invention relates to the domain of a battery pack, more specifically the present application is related to the battery pack comprising at least two different Phase Change Materials (PCM).
5
BACKGROUND
[0002] Battery pack, such as Lithium-ion (Li-ion) battery pack or the like, are used to power components in applications, such as electric vehicles, hybrid vehicles, mobile phones, laptops, medical equipment’s or the like. A battery pack has a plurality of cells in electrical connection with each other. 10
[0003] The battery pack are commonly used in various fields, for example, the battery pack serve as power sources for personal electronic devices like cell mobile phones, laptops, camera, electronic devices and the like. Further, the battery pack supplies possess desirable properties such as recharging capability, 15 making them attractive as potential power sources for automobile industry such as but not limited for automobile industry.
[0004] A lithium-ion battery is usually constituted of a positive electrode, a negative electrode, an electrolyte, and a separator. As a positive electrode active 20 material to be used for the positive electrode, lithium cobaltate, manganese spinel, or the like are mainly used. Since the positive electrode active material has a high electric resistance, the electric resistance of the positive electrode is decreased by using carbon-based conductive additives. As a binder, for example, styrene-butadiene rubber, fluororubber, synthetic rubber, a polymer such as 25 polyvinylidene fluoride, an acryl resin, or the like are used.
[0005] A negative electrode active material to be used is natural graphite, artificial graphite obtained by thermally treating coal, petroleum pitch or the like at a high temperature, amorphous carbon obtained by thermally treating coal, 30 petroleum pitch coke, acetylene pitch coke or the like, a lithium alloy such as metallic lithium or AlLi, or the like. Further, carbon-based conductive additives are used for a negative electrode in some cases for the purpose of decreasing the resistance.
3
[0006] A holder used for battery adhesion-fixation structure has been usually provided with multiple holder holes. More specifically, a battery cell is inserted into each of the holder holes and is adhered or bonded with the holder via an adhesive agent onto an inner peripheral face of the holder holes. Moreover, an 5 electrode terminal located at one of the opposite ends of the battery cells is exposed at one of the axials opposite ends of the holder holes. In addition, a bus bar connects electrically between the electrode terminals exposed at the one of the axials opposite ends of the holder holes.
10
[0007] Battery pack comprises plurality of cells in electrical connection with each other. During operation, each cell generates heat which is to be dissipated from the battery pack to ensure proper operation of the battery pack without failing. More specifically, the battery pack, such as Lithium-ion (Li-ion) battery pack, have an issue of thermal runaway. For instance, when a cell or an area 15 within the cell or a plurality of cells of a Li-ion battery pack achieves an elevated temperature due to a thermal failure or a mechanical failure or internal or external short circuiting or an electro-chemical abuse a large amount of heat is generated. When the generated heat is larger than the heat dissipation, various side reactions between the components inside the battery pack are induced. This may cause 20 further heat generation and the pressure and the temperature of the battery pack may increase sharply. This may lead to inflammation and/or explosion of the battery pack. This process is referred to as thermal runaway. Accordingly, during operation of the battery pack, to avoid thermal runaway and to ensure proper operation of the battery pack without failing, heat generated by each cell is to be 25 dissipated from the battery pack.
[0008] In a battery pack at higher temperature, the cells within a battery pack experience irreversible by-reactions that result in the degradation of the material of the cells. These by-reactions, often referred to as side reactions, occur due to 30 the chemical and electrochemical processes happening within the cells. The degradation of the cell material leads to an increase in cell resistance, which subsequently affects the overall resistance of the battery pack. Therefore, the overall increase in resistance of the battery pack delays the efficient flow of
4
electrical current during both charging and discharging cycles. Accordingly, the performance and capacity of the cells are negatively impacted, leading to reduced energy storage capabilities and decreased overall battery pack efficiency.
[0009] During operation, the use of the battery pack results in the generation of 5 heat due to exothermic reactions and internal resistances. Further, prolonged exposure of lithium-ion cells to high temperatures can cause various detrimental effects, including cell degradation, decreased health, reduced charge and efficiency, and an increase in internal resistance.
10
[00010] Conventional solutions available in the art for the battery pack cooling is to integrate thermal management systems into battery power supply systems, utilizing active cooling methods such as forced circulation of air, liquid, or other chosen cooling mediums. Active cooling can take different forms, including internal active cooling, where the cooling medium circulates within the battery 15 module or pack, and external active cooling, where the cooling medium circulates outside the battery module. However, the problem available with the available solutions is that incorporating internal active cooling may introduce additional weight and complexity to the design and operation of the power supply, potentially limiting the widespread adoption of such systems. Further, 20 the use of such materials causes handling problems with the battery pack.
[00011] In one of the solutions available in the art a cell can be immersed in a Phase Change Materials (PCM) that is specifically configured to absorb any heat generated by the cells. When the PCM undergoes a phase change from solid to 25 liquid, it requires a considerable amount of energy, which is provided by the heating cell in the current configuration. The key characteristic of the PCM is that, while it continues to absorb heat from the cell, there will not be a steep temperature gradient established within the PCM. This means that until the PCM fully melts, reaching its maximum phase change capacity, there will not be a 30 significant increase in the PCM's temperature. However, the existing design available in the art employs a single PCM with a narrow range of phase transition temperature (PTT). Accordingly, the cooling effect can only be observed within
5
the PTT range. At temperatures below or above the PTT range, there is no substantial cooling advantage provided by the PCM.
[00012] The above information as disclosed in this background section is only for enhancement of understanding of the background of the disclosure and therefore 5 it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.
SUMMARY
[00013] It is to be understood that both the foregoing general description and the 10 following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.
[00014] In one of the embodiments of the present application, a battery pack comprising plurality of cells, one or more cell holder and at least one cavity plate 15 which are placed inside a casing. The one or more cell holder comprising plurality of opening to accommodate at least one end of the plurality of cells. The at least one cavity plate is in contact with the one or more cell holder of the battery pack. Further, the at least one cavity plate comprising one or more cavities which are filled with at least two different Phase Change Materials 20 (PCM). Furthermore, latent heat capacity of the at least two different PCM is different from each other.
[00015] In one of the embodiments of the present application, the casing of the battery pack comprising a casing top, a casing bottom and one or more casing 25 vertical walls. Further, the casing top and the casing bottom being connected with each other to form the casing of the battery pack. Furthermore, the casing top and the casing bottom being connected with each other using one or more casing vertical walls to form the casing of the battery pack. Moreover, the casing being made of a thermally conductive material and an electrically insulating material. 30
[00016] In one of the embodiments of the present application, the plurality of cells is potted in the at least one cavity plate. Further, the at least one cavity plate is made up of thermally conductive and electrically insulated material.
6
Furthermore, the at least one cavity plate is in connection with a casing bottom of the battery pack.
[00017] In one of the embodiments of the present application, the battery pack further comprising a first layer which is made up of thermally conductive and 5 electrically insulated material. Further, the first layer is placed between the cell holder and the at least one cavity plate.
[00018] In one of the embodiments of the present application, the battery pack further comprising a second layer which is made up of thermally conductive and 10 electrically insulated material. Further, the second layer is present between second end of the plurality of cells and the casing top of the battery pack.
[00019] In one of the embodiments of the present application, the second layer is pours to allow venting of hot air gases from the plurality of cells. 15
[00020] In one of the embodiments of the present application, the at least two different PCM are mixed in a pre-defined ratio and enclosed in each cavity of the one or more cavities.
20
[00021] In one of the embodiments of the present application, the plurality of cells being enclosed in an insulative encapsulant.
[00022] In one of the embodiments of the present application, the battery pack comprises one or more sensors such as temperature sensor, pressure sensors or 25 the like.
[00023] In one of the embodiments of the present application, first cell holder of the one or more cell holder is holding positive end of the plurality of cells and second cell holder of the one or more cell holder is holding negative end of the 30 plurality of cells. Further, the first cell holder of the one or more cell holder is placed close to the casing top and the second cell holder of the one or more cell holder is placed close to the casing bottom of the battery pack.
7
[00024] In one of the embodiments of the present application, the casing comprises a plurality of heat dissipating fins. Further, the plurality of heat dissipating fins is disposed on an outer surface of the casing of the battery pack.
[00025] In one of the embodiments of the present application, one end of the one 5 or more cavities is in contact with the at least one cavity plate and second end of the one or more cavities is closed using PCM sealant. Further, the second end of the one or more cavities is facing the casing of the battery pack.
[00026] In one of the embodiments of the present application, first PCM of the at 10 least two different PCM with lower latent heat capacity is placed close to the at least one cavity plate. Further, second PCM of the at least two different PCM with higher latent heat capacity is placed close to the casing of the battery pack.
[00027] In one of the embodiments of the present application, the at least two 15 different PCM is filed inside the one or more cavities using injecting process.
[00028] In one of the embodiments of the present application, the one or more cavities of the at least one cavity plate are placed parallelly to one another.
20
[00029] 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 FIGURES: 25
[00030] The accompanying drawings, which are incorporated herein and constitute part of this specification, illustrate preferred embodiments of the invention, and together with the general description given above and the detailed description given below, serve to explain features of the invention.
30
[00031] Figure 1 illustrates a battery pack as per one of the embodiments of the present invention.
8
[00032] Figure 2 illustrates exploded view of the battery pack as per one of the embodiments of the present invention.
[00033] Figure 3 illustrates a perspective side view of the one or more cavities as per one of the embodiments of the present invention. 5
DETAILED DESCRIPTION
[00034] Exemplary embodiments detailing features of a battery pack in accordance with the present subject matter will be described hereunder with reference to the accompanying drawings. Various aspects of different 10 embodiments of the present invention will become discernible from the following description set out hereunder. Rather, the following description provides a convenient illustration for implementing exemplary embodiments of the present subject matter. Further, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be 15 regarded as limiting. Additionally, all numerical terms, such as, but not limited to, “first”, “second”, “third”, “primary”, “secondary”, “main” or any other ordinary and/or numerical terms, should also be taken only as identifiers, to assist the reader's understanding of the various elements, embodiments, variations and/or modifications of the present disclosure, and may not create any 20 limitations, particularly as to the order, or preference, of any element, embodiment, variation and/or modification relative to, or over, another element, embodiment, variation and/or modification.
[00035] The following detailed description refers to the accompanying drawings. 25 Wherever possible, the same reference numbers are used in the drawings and the following description to refer to the same or similar elements. While embodiments may be described, modifications, adaptations, and other implementations are possible. For example, substitutions, additions, or modifications may be made to the elements illustrated in the drawings, and the 30 methods described herein may be modified by substituting, reordering, or adding stages to the disclosed methods. Accordingly, the following detailed description does not limit the claimed subject matter. Instead, the proper scope of the claimed subject matter is defined by the appended claims. It should be noted that the
9
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 5 equivalents thereof.
[00036] Further, various embodiments disclosed herein are to be taken in the illustrative and explanatory sense and should in no way be construed as limiting of the present disclosure. All joinder references (e.g., attached, affixed, coupled, 10 disposed, etc.) are only used to aid the reader's understanding of the present disclosure, and may not create limitations, particularly as to the position, orientation, or use of the systems and/or methods disclosed herein. Therefore, joinder references, if any, are to be construed broadly. Moreover, such joinder references do not necessarily infer those two elements are directly connected to 15 each other.
[00037] It will also be appreciated that one or more of the elements depicted in the drawings/figures can also be implemented in a more separated or integrated manner, or even removed or rendered as inoperable in certain cases, as is useful 20 in accordance with a particular application. Additionally, any signal hatches in the drawings/figures should be considered only as exemplary, and not limiting, unless otherwise specifically specified.
[00038] With the initiation of electric vehicles and electric vehicles, there is a 25 growing interest in an automotive industry to develop electrical machines which dissipate heat properly from the cells of the battery pack, light in weight, utilize less space and are efficient in operation. Therefore, the direction of innovation in designing electrical machines is to develop electrical machines which have good heat dissipation, lighter in weight and compact size for a given power rating, or 30 for a given size, power rating should be more than the present rating. However, in general, close packaging of components in compact machines leads to greater electrical and magnetic interactions between the components and may lead to high core losses in case of electrical machines using permanent magnets.
10
[00039] Battery pack comprises a plurality of cells in electrical connection with each other. During operation, each cell generates heat which is to be dissipated from the battery pack to ensure proper operation of the battery pack without failing. More specifically, battery pack, such as Lithium-ion (Li-ion) battery pack 5 or the like, have an issue of thermal runaway. For instance, when a cell, an area within the cell, or a plurality of cells of a Li-ion battery pack achieves an elevated temperature due to a thermal failure, a mechanical failure, internal or external short circuiting, or an electro-chemical abuse, a large amount of heat is generated. When the heating generated is larger than the heat dissipation, various 10 side reactions between components inside the battery pack are induced. This may cause further heat generation and the pressure and the temperature of the battery pack may increase sharply. This may lead to inflammation and/or explosion of the battery pack. This process is referred to as the thermal runaway.
15
[00040] The present subject matter relates to heat transfer in power unit assembly such as but not limited to battery pack assemblies. With the implementations of the present subject matter, heat generated by the cells of the battery pack assemblies can be efficiently dissipated from the battery pack assemblies, thereby, the thermal runaway can be eliminated. 20
[00041] With reference to figure 1, in which a battery pack (100) is shown. The battery pack (100) comprises a casing (108) to provide a cover and to protection to the components of the battery pack (100). Particularly, the casing (108) encloses the plurality of cells (214), as shown in figure 2, present inside the 25 power unit assembly (100). In addition to providing cover and protecting components of the power unit assembly (100), the casing (108) may facilitate dissipating the heat away from the power unit assembly (100) to the surroundings. The power unit assembly (100) may be a battery pack, also in the present specification the terms battery pack and power unit assembly are used 30 interchangeably. Accordingly, in an example, the casing (108) may be made of a thermally conductive and electrically insulating material. The power unit assembly (100) comprises a casing top (102) and a casing bottom (222), as shown in figure 2, are connected using means (106) available in the art. The casing top
11
(102) is placed opposite to the casing bottom (222). Further, the casing top (102) and the casing bottom (222) are connected with each other using plurality of vertical walls (104) to form the casing (108) of the power unit assembly (100).
[00042] In one of the embodiments of the present application, the battery pack 5 (100) also comprises plurality of heat dissipating fins present on the casing for dissipating heat from inside the battery pack (100) to the surroundings. The casing top (102) and the casing bottom (222) comprises an inner area which is facing inside the battery pack (100) and an outer area which is opposite to the inner area and comprises plurality of heat dissipating fins. 10
[00043] With reference to figure 2, an exploded view (200) of the battery pack (100) is shown and in figure 3 perspective side view (300) of the one or more cavities (220) of the battery pack (100) is shown. For the sake of brevity, figure 2 and figure 3 are explained in conjunction with each other. In the exploded view 15 (200), the battery pack (100) comprises the casing top (102) and the casing bottom (222). The battery pack (100) also comprises a second layer (210) which is placed underneath the casing top (102). Further, the second layer (210) is made up of thermally conductive and electrically insulated material. In one of the embodiments of the present application, the second layer (210) is pours to allow 20 venting of hot air gases from the plurality of cells (214). The ends of the casing top (102) comprise means (106) to connect the casing top (102) with the casing bottom (222) using known means available in the art such as but not limited to bold configuration, welding, or the like. In the figure1 and figure 2 bolting configuration is shown where one or more bolts (202) were used to connect the 25 casing top (102) with the casing bottom (222). More specifically, the ends of the casing top (102) comprise first opening (204) which are placed parallelly to second openings (206) of the second layer (210) and third opening (208) of the casing bottom (222). Accordingly, the one or more bolts (202) are used to connect the first opening (204) of the casing top (102), the second openings (206) 30 of the second layer (210) and the third opening (208) of the casing bottom (222) to provide a rigid structure to the casing (108) of the battery pack (100).
12
[00044] The battery pack (100) also comprises one or more cell holder (212, 216) which are required to hold the plurality of cells (214) on its position. The one or more cell holder (212, 216) is comprising plurality of opening (224) to accommodate at least one end of the plurality of cells (214). In the figure 2 and figure 3, a first cell holder (212) of the one or more cell holder (212, 216) is 5 placed close to the casing top (102) and comprising one end of the of the plurality of cells (214). Further, a second cell holder (214) of the one or more cell holder (212, 216) is placed close to the casing bottom (222) and comprising second end of the of the plurality of cells (214). The plurality of cells (214) being enclosed in an insulative encapsulant. 10
[00045] In one of the embodiments of the present application, the first cell holder (212) of the one or more cell holder (212, 216) is comprising positive end of the of the plurality of cells (214). Further, the second cell holder (214) of the one or more cell holder (212, 216) is comprising negative end of the of the plurality of 15 cells (214).
[00046] The plurality of cells (214) in the battery pack (100) is potted in the at least one cavity plate (218). Further, the at least one cavity plate (218) is made up of thermally conductive and electrically insulated material. Furthermore, the 20 at least one cavity plate (218) is facing the casing (108) of the battery pack (100). More specifically, the at least one cavity plate (218) is facing either one or more casing vertical walls (104), casing bottom (222) or the casing top (102) based on the configuration and requirement of the battery pack (100).
25
[00047] The at least one cavity plate (218) is comprising one or more cavities (220) which are filled with at least two different Phase Change Material (PCM), wherein latent heat capacity of the at least two different PCM is different. The at least two different PCM are mixed in a pre-defined ratio and enclosed in each cavity of the one or more cavities (220). This mixture of the at least two different 30 PCM is then placed and sealed within each individual cavity of the one or more cavities (220). The one or more cavities (220) are placed parallelly to one another. The pre-defined ratio refers to the specific proportion in which the at
13
least two different PCM are blended together. This ratio is determined based on factors such as but not limited to the desired cooling performance, the specific temperature range requirements, and the characteristics of the PCMs being used. The ratio can be adjusted and optimized to achieve the desired cooling effect and stage-wise melting behaviour. Further, once the at least two different PCM are 5 mixed in the predetermined ratio, the resulting PCM mixture is filled into each individual cavity of the one or more cavities (220). The one or more cavities (220) are designed to contain a significant amount of the resulting PCM mixture, ensuring sufficient thermal mass and heat absorption capacity. Furthermore, the resulting PCM mixture within each individual cavity of the one or more cavities 10 (220) is then securely sealed to prevent any leakage or mixing between different cavities. This encapsulation ensures that each individual cavity of the one or more cavities (220) contains the resulting PCM mixture, maintaining the intended stage-wise melting behaviour and providing efficient thermal management throughout the battery pack (100). 15
[00048] In one of the embodiments of the present application, the at least one cavity plate (218) is made up of a potting material. The potting material is good thermal conductivity with electrical insulation. It serves as a thermal interface material and provides structural integrity to the plurality of cells (214) thereby 20 functioning as one or more cell holder (212, 216) for the bottom portion. The potting material composition is polyurethane or an epoxy with additives to improve electrical insulation. The potting materials can be made from various types of polymers, such as but not limited to epoxy resins, polyurethanes, silicone rubbers, or other thermosetting or thermoplastic compounds. These materials are 25 selected based on their specific properties, including adhesion, thermal conductivity, flexibility, chemical resistance, and compatibility with the enclosed plurality of the cells (214) or the at least two different PCM.
[00049] Phase change materials (PCMs) are available in the art and offer a 30 captivating alternative for passive thermal management in the battery pack (100), specially, the battery pack (100) which are used in automobile industry. The PCMs possess the ability to store thermal energy in both latent and sensible forms, which can then be released in the opposite direction. More specifically,
14
as the temperature of the battery pack (100) increases, the PCM absorbs and stores energy initially as sensible heat and subsequently as latent heat when it reaches the phase transition temperature. Further, the stored energy is then released as the temperature decreases below the phase transition temperature, restoring the PCM to its original state. Furthermore, the selection of PCM for the 5 battery pack (100) is based on its melting point, which is crucial for achieving an isothermal phase change process. The at least two different PCM which can be used in the battery pack (100) are Paraffin Wax, Salt Hydrates, Eutectic Mixtures, Metal Alloys, Polymeric PCMs, Inorganic PCMs, Bio-based PCMs, or the like. The choice of PCM can be selected on the basis of the specific 10 application requirements of the battery pack (100), such as the desired phase transition temperature range, latent heat capacity, thermal conductivity, environmental considerations, or the like.
[00050] The one or more cavities (220) comprises at least two ends such that the 15 one end is in connection with the at least one cavity plate (218) and the second end is facing towards the casing (108) of the battery pack (100). Further, the second end of the one or more cavities (220) is closed using PCM sealant such that the at least two different PCM will not come out from the one or more cavities (220). Furthermore, the at least two different PCM is filed inside the one 20 or more cavities (220) using injecting process.
[00051] The PCM sealant refers to a sealant or adhesive material which is required to seal the second end of the one or more cavities (220). Further, the PCM sealants are designed to provide both sealing and thermal management properties 25 in various applications. When exposed to elevated temperatures in the battery pack (100), the PCM sealant absorbs and stores thermal energy as it undergoes a phase change and helps to regulate the temperature and prevent overheating in the surrounding area.
30
[00052] In one of the embodiments of the present application, first PCM of the at least two different PCM with lower latent heat capacity is placed close to the at least one cavity plate (218). Further, second PCM of the at least two different PCM with higher latent heat capacity is placed close to the casing (108) of the
15
battery pack (100). The latent heat is the heat or energy that is absorbed or released during a phase change of a substance.
[00053] In the event of a temperature increase inside the battery pack (100), the PCM of the at least two different PCM with the lowest Phase Transition 5 Temperature (PTT) will reach its phase transition temperature first and begin to melt. As it undergoes a phase change, it absorbs a significant amount of thermal energy from inside the battery pack (100). This energy absorption prevents the temperature from rising inside the battery pack (100) further until the PCM with the lowest PTT has completely melted. As the temperature continues to increase 10 inside the battery pack (100), the PCM of the at least two different PCM with the next highest PTT in the mixture will reach its phase transition temperature. This PCM will then undergo its own stage-wise melting process, absorbing additional thermal energy and contributing to the cooling effect. Accordingly, as the temperature further rises inside the battery pack (100), the PCMs with higher 15 PTTs in the mixture will sequentially melt, continuing the stage-wise melting process. The stage-wise melting of the at least two different PCM mixture over a range of temperature allows for a controlled and gradual release of thermal energy from the battery pack (100), thereby providing an extended time window of cooling. This staged melting process helps to regulate and stabilize the 20 temperature within the battery pack (100), mitigating the rapid temperature increase that could lead to overheating or thermal damage.
[00054] The use of at least two different PCM with different PTTs in a mixture enables a cooling effect through stage-wise melting. By sequentially melting at 25 specific temperature thresholds, the PCMs effectively absorb and dissipate thermal energy, preventing a sudden temperature rise and providing a sustained cooling effect over an extended period. Accordingly, using the at least two different PCM will provide plurality of cells (214) an opportunity to operate optimally by controlling temperature levels. Further, effective thermal 30 management of the plurality of cells (214) during operation is ensured. The occurrence of thermal runaway is delayed, providing users with ample time to escape safely in case of an emergency. This delay in the onset of thermal runaway is further achieved by venting gases and smoke from the battery pack (100) and
16
providing users with ample time to safely evacuate from the vicinity of the battery pack (100), in case of any unwanted event.
[00055] In one of the embodiments of the present application, the battery pack (100) comprises one or more sensors such as temperature sensor, pressure sensor 5 of the like which are used to monitor various parameters of the battery pack (100).
[00056] In one of the embodiments of the present application, the battery pack (100) comprises a first layer is made up of thermally conductive and electrically 10 insulated material. Further, the first layer is placed between the one or more cell holder (212, 216) and the at least one cavity plate (218).
[00057] In one of the embodiments of the present application, the battery pack (100) also comprises one or more interconnectors to connect the two ends of the 15 plurality of cells (214) in parallel, series or a combination of parallel and series connection based on requisite power output of the battery pack (100).
[00058] In one of the embodiments of the present application, the plurality of cells (214) of the battery pack (100) are encapsulated in a potting encapsulant. The 20 potting encapsulant is a good conductor of heat but bad conductor of electricity accordingly, chances of short circuiting will be eliminated from the battery pack (100).
[00059] The present application is also used for maintaining an optimal 25 temperature range for the efficient operation of the battery pack (100). The identified optimal temperature range falls between 30 and 60 degrees Celsius. Unlike conventional thermal management systems that primarily address overheating, exothermic reactions, or thermal runaway once the temperature exceeds around 60 degrees Celsius, the battery pack (100) of the present 30 application takes action at approximately 35 degrees Celsius. At this temperature, one of the at least two different PCM within the battery pack (100) begins absorbing energy to initiate a phase change within itself, thereby ensuring optimal temperature maintenance rather than solely focusing on risk mitigation.
17
[00060] The use of the at least two different PCM with different PTT allows for precise temperature regulation. As the temperature rises inside the battery pack (100), the PCM with the lowest phase transition temperature melts first, preventing further temperature increase until it is completely melted. This stage-5 wise melting of the PCM mixture over a range of temperatures provides efficient and controlled cooling, maintaining the temperature within desired limits inside the battery pack (100).
[00061] The stage-wise melting of the at least two different PCM mixture results 10 in an extended time window of cooling inside the battery pack (100). Further, the at least two different PCM in the mixture melts sequentially as the temperature rises, absorbing thermal energy and releasing it gradually. This prolonged cooling effect helps prevent rapid temperature spikes and ensures stable operating conditions for the battery pack (100). 15
[00062] The use of the at least two different PCM in the battery pack (100) contributes to risk mitigation by preventing thermal runaway. Further, by delaying the occurrence of thermal runaway through the controlled melting of the at least two different PCM, the present application provides crucial time for 20 users to evacuate the area safely, reducing the risk of accidents and improving overall safety.
[00063] The implementation of the one or more cavities (220) filled with at least two different PCM in the battery pack (100) helps maintain the plurality of cells 25 (214) within the optimal temperature range. By preventing excessive heat buildup and minimizing temperature fluctuations, the present application helps preserve the battery pack (100) capacity and extend its service life. Further, the same will results in better heat management and helps keep the plurality of cells (214) within the desired temperature range and accordingly optimizing their 30 performance.
[00064] The present application can be adapted to various battery types and sizes, making it suitable for a wide range of applications. The composition of the at
18
least two different PCM can be tailored to match the specific temperature requirements and characteristics of different battery chemistries, allowing for customization and optimization of the thermal management system.
[00065] The present application offers a cost-effective thermal management 5 solution compared to complex active cooling systems. The at least two different PCM-based cooling systems typically require less maintenance, have lower energy consumption, and involve fewer moving parts compared to traditional cooling methods, resulting in reduced operational costs over the battery pack (100) lifespan. 10
[00066] With the implementations of the present subject matter, the heat generated by the plurality of cells (214) of the battery pack (100) can be efficiently dissipated from the battery pack, thereby (100), the thermal runaway can be eliminated. Accordingly, the plurality of cells (214) is thermally efficient 15 and electrically safe.
[00067] In view of the above, the present invention as discussed above are not routine, conventional, or well understood in the art, as the claimed steps enable the following solutions to the existing problems in conventional technologies. 20
[00068] The above-described embodiments, and particularly any “preferred” embodiments, are possible examples of implementations and merely set forth for a clear understanding of the principles of the invention. It will be apparent to those skilled in the art that changes in form, connection, and detail may be made 25 therein without departing from the spirit and scope of the invention.
[00069] Non-limiting and non-exhaustive embodiments of the invention are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise 30 specified. It should be appreciated that the following figures may not be drawn to scale.
19
[00070] The foregoing disclosure is not intended to limit the present disclosure to the precise forms or particular fields of use disclosed. As such, it is contemplated that various alternate embodiments and/or modifications to the present disclosure, whether explicitly described or implied herein, are possible in light of the disclosure. Having thus described embodiments of the present disclosure, 5 a person of ordinary skill in the art will recognize that changes may be made in form and detail without departing from the scope of the present disclosure. Therefore, it is intended that the present invention not be limited to the particular embodiment disclosed, but that the present invention will include all embodiments falling within the scope of the appended claims. 10
[00071] In the foregoing specification, the disclosure has been described with reference to specific embodiments. However, as one skilled in the art will appreciate, various embodiments disclosed herein can be modified or otherwise implemented in various other ways without departing from scope of the 15 disclosure. Accordingly, this description is to be considered as illustrative and is for the purpose of teaching those skilled in the art the manner of making and using various embodiments of the disclosure. It is to be understood that the forms of disclosure herein shown and described are to be taken as representative embodiments. Equivalent elements, materials, processes or steps may be 20 substituted for those representatively illustrated and described herein. Moreover, certain features of the disclosure may be utilized independently of the use of other features, all as would be apparent to one skilled in the art after having the benefit of this description of the disclosure. Expressions such as “including”, “comprising”, “incorporating”, “consisting of”, “have”, “is” used to describe and 25 claim the present disclosure are intended to be construed in a non-exclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural. , Claims:We Claim:
1. A battery pack (100) comprising:
a casing (108);
plurality of cells (214), the plurality of cells (214) is placed inside the 5 casing (108);
one or more cell holder (212, 216), the one or more cell holder (212, 216) is comprising plurality of opening (224) to accommodate at least one end of the plurality of cells (214); and
at least one cavity plate (218), the at least one cavity plate (218) is in 10 contact with the one or more cell holder (212, 216);
wherein the at least one cavity plate (218) comprising:
one or more cavities (220), the one or more cavities (220) are filled with at least two different Phase Change Material (PCM), wherein latent heat capacity of the at least two different PCM is different. 15
2. The battery pack (100) as claimed in claim 1, wherein the casing (108) of the battery pack (100) comprises:
a casing top (102);
a casing bottom (222); and 20
one or more casing vertical walls (104);
wherein the casing top (102) and the casing bottom (222) being placed opposite to each other;
wherein the casing top (102) and the casing bottom (222) being connected with each other using the one or more casing vertical walls (104); and 25
wherein the casing (108) being made of a thermally conductive material and an electrically insulating material.
3. The battery pack (100) as claimed in claim 1, wherein the plurality of cells (214) is potted in the at least one cavity plate (218); the at least one cavity plate (218) 30 is made up of thermally conductive and electrically insulated material and the at least one cavity plate (218) is facing the casing (108) of the battery pack (100).
21
4. The battery pack (100) as claimed in claim 1, further comprising a first layer, the first layer is made up of thermally conductive and electrically insulated material is placed between the one or more cell holder (212, 216) and the at least one cavity plate (218).
5
5. The battery pack (100) as claimed in claim 2, further comprising a second layer (210), the second layer (210) is made up of thermally conductive and electrically insulated material; the second layer (210) is present between second end of the plurality of cells (214) and the casing top (102) of the battery pack (100).
10
6. The battery pack (100) as claimed in claim 5, wherein the second layer (210) is pours to allow venting of hot air gases from the plurality of cells (214).
7. The battery pack (100) as claimed in claim 1, wherein the at least two different PCM are mixed in a pre-defined ratio and enclosed in each cavity of the one or 15 more cavities (220).
8. The battery pack (100) as claimed in claim 1, wherein the plurality of cells (214) being enclosed in an insulative encapsulant.
20
9. The battery pack (100) as claimed in claim 1, wherein the battery pack (100) comprises one or more sensors and the one or more sensors comprises temperature sensor.
10. The battery pack (100) as claimed in claim 2, wherein first cell holder (212) of 25 the one or more cell holder (212, 216) is holding positive end of the plurality of cells (214) and second cell holder (216) of the one or more cell holder (212, 216) is holding negative end of the plurality of cells (214); wherein the first cell holder (212) of the one or more cell holder (212, 216) is placed close to the casing top (102) and the second cell holder (216) of the one or more cell holder (212, 216) 30 is placed close to the casing bottom (222) of the battery pack (100).
11. The battery pack (100) as claimed in claim 2, wherein the casing (108) comprises a plurality of heat dissipating fins; and wherein the plurality of heat dissipating
22
fins being disposed on an outer surface of the casing (108) of the battery pack (100).
12.The battery pack (100) as claimed in claim 1, wherein one end of the one or morecavities (220) is in contact with the at least one cavity plate (218) and second end5 of the one or more cavities (220) is closed using PCM sealant and wherein thesecond end of the one or more cavities (220) is facing the casing (108) of thebattery pack (100).
13.The battery pack (100) as claimed in claim 1, wherein first PCM of the at least10 two different PCM with lower latent heat capacity is placed close to the at leastone cavity plate (218) and wherein second PCM of the at least two different PCMwith higher latent heat capacity is placed close to the casing (108) of the batterypack (100).
15
14.The battery pack (100) as claimed in claim 2, wherein the at least two differentPCM is filed inside the one or more cavities (220) using injecting process.
15.The battery pack (100) as claimed in claim 1, wherein the one or more cavities(220)of the at least one cavity plate (218) is placed parallelly to one another.20
Dated this 27th day of July 2023.