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 a material for a battery cover of a battery pack and a method of making the material which reduces the propagation of fire in battery packs.
BACKGROUND
[0002] The development and popularity of electric vehicles (hereinafter referred to as EV) brings in safety concerns with regard to the propensity of fire hazard in the batteries being used in the EVs. Thermal runaway in EV batteries leads to major fires which often results in loss of vehicles and loss of life. In light of common fire incidents in EVs there is a dire need for the development of improved safety mechanisms for critical parts such as EV batteries, with safety mechanisms being directed at reducing the propagation of fires from the batteries leading to confinement of the fire mishap.
[0003] Thermal runaway in batteries relates to an accelerated release of heat inside a battery cell due to uncontrolled exothermic reactions. In scenarios of uncontrolled exothermic reactions the battery cells can no longer dissipate the heat as quickly as the heat is generated in the battery cell, ultimately leading to a loss of thermal stability of the battery cell. The heat generated in the battery cells during thermal runaway can propagate to neighboring electrical or electronic components leading to catastrophic failure.
[0004] Lithium-ion batteries (hereinafter referred to as LIBs), have features such as high energy density, high power density, excellent cycle performance and environmental friendliness, and are widely used in energy storage systems for EVs and other electrical or electronic machinery. However, LIBs have great propensity of catastrophic failure in events of thermal runaway as the heat energy released from a single failing LIB cell during thermal runaway can cause a chain reaction in the neighboring LIB cells.
[0005] Further, the strengthening of the safety parameters in testing of the batteries is necessary in EVs. Subsequently in view of the improved safety for the developed battery packs for EVs, the developed battery packs are subjected to component level testing which need to adhere to pre-defined fire resistance testing safety measures.
[0006] Thus, there is a requirement of an effective fire-resistant material to adhere to the pre-defined fire resistance safety measures when an EV battery is subjected to component level testing. In adherence to component level testing of EV batteries the EV batteries should possess a higher time threshold to catch fire when subjected to direct flames. Following the EV batteries being subjected to direct flames, the EV batteries must possess self-extinguishing properties once the direct flame is removed. The self-extinguishing properties of the EV batteries prevent further thermal propagation of the heat energy manifested in the form of fire to the nearby parts of the EV or equivalent electrical components.
[0007] Conventional vehicles employ a metal casing such as steel for battery pack covers however metal casings using steel have not been found to be adequately effective against fire propagation to nearby parts and lead to catastrophic failure and safety issues. Metal casings also lack self-extinguishing properties. Further, use of metal casings in battery pack covers increases the overall weight of the battery pack and the vehicle, and subsequently adds to component cost of the vehicle.
SUMMARY OF THE INVENTION
[0008] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.
[0009] According to embodiments illustrated herein, the present invention provides a battery pack provided with a battery cover having at least a top cover, a bottom cover and a centre cover. The centre cover is composed of aluminium and the bottom cover is composed of a material being at least one of a first combination, a second combination and a third combination. The first combination of material includes polypropylene and long glass fibres. The second combination of material includes polycarbonate and acrylonitrile butadiene styrene. The third combination of material includes polyphenylene ether, polystyrene and glass fibre. The material being in at least one of the first combination, the second combination and the third combination includes a non-halogen flame retardant compound in at least 5% to 40% be weight of the material. The disclosed battery pack with a battery cover is configured to have fire resistant and self-extinguishing properties which restrict the propagation of fire generated in the battery pack to nearby parts of electrical or electronic components in avoidance of catastrophic failure.
[00010] According to embodiments illustrated herein, the present invention also provides a method for manufacturing of a battery pack, wherein said method consisting of the steps of creating a mould for the battery cover consisting of a top cover, a bottom cover and a centre cover. The method further comprises of synthesizing a material for the battery cover composed by alloying at least one of a first combination, a second combination and a third combination. In an embodiment, the first combination of material includes polypropylene and long glass fibres. In an embodiment, the second combination of material includes polycarbonate and acrylonitrile butadiene styrene. In an embodiment, the third combination of material includes polyphenylene ether, polystyrene and glass fibre. The method further comprises of allowing the material comprising of at least one of the first combination, the second combination and the third combination to include a non-halogen flame retardant compound in at least 5% to 40% be weight of the material. The method further comprises of injecting the synthesized material for the battery cover into the created mould in molten form after which the mould is cooled to allow hardening of the molten synthesized material to form the battery cover for the battery pack. The method further comprises of ejecting the the formed battery cover for the battery pack from the mould.
BRIEF DESCRIPTION OF THE DRAWINGS
[00011] The present invention will become more fully understood from the detailed description given herein below and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and therein.
[00012] Figure 1 exemplarily illustrates a top perspective view of a battery pack, in accordance with some embodiments of the present disclosure.
[00013] Figure 2 exemplarily illustrates an exploded top perspective view of a battery pack, in accordance with some embodiments of the present disclosure.
[00014] Figure 3 exemplarily illustrates a top perspective view of a battery back cover as per an embodiment of the present invention.
[00015] Figure 4 exemplarily illustrates a flowchart depicting the process of manufacture of the battery pack, in accordance with some embodiment of the present disclosure.
DETAILED DESCRIPTION
[00016] The present disclosure may be best understood with reference to the detailed figures and description set forth herein. Various embodiments are discussed below with reference to the figures. However, those skilled in the art will readily appreciate that the detailed descriptions given herein with respect to the figures are simply for explanatory purposes as the methods and systems may extend beyond the described embodiments. For example, the teachings presented and the needs of a particular application may yield multiple alternative and suitable approaches to implement the functionality of any detail described herein. Therefore, any approach may extend beyond the particular implementation choices in the following embodiments described and shown.
[00017] References to “one embodiment,” “at least one embodiment,” “an embodiment,” “one example,” “an example,” “for example,” and so on indicate that the embodiment(s) or example(s) may include a particular feature, structure, characteristic, property, element, or limitation but that not every embodiment or example necessarily includes that particular feature, structure, characteristic, property, element, or limitation. Further, repeated use of the phrase “in an embodiment” does not necessarily refer to the same embodiment.
[00018] The present invention now will be described more fully hereinafter with different embodiments. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather those embodiments are provided so that this disclosure will be thorough and complete, and fully convey the scope of the invention to those skilled in the art.
[00019] The present invention is illustrated with a battery pack and explained with reference to a battery cover for the battery pack. However, a person skilled in the art would appreciate that the present invention is not limited to a battery pack and certain features, aspects and advantages of embodiments of the present invention can be extended to other forms of energy storage devices used with various types of vehicles, electric vehicle, hybrid vehicles and other forms of electrical and electronic equipment requiring an energy storage device. In an embodiment, the battery pack is configured to supply electrical energy to an external electrical load. The electrical load refers to, but is not limited to, electrical vehicles, hybrid vehicles and other electrical and electronic equipment requiring electrical energy. Additionally, the term “vehicle” used in the present disclosure shall not be narrowly construed to relate to two, three or four-wheeler vehicles but shall be extended to all forms of mobility and locomotion capable of drawing or utilising electrical energy from a battery pack or an energy storage device for its operation.
[00020] It is an object of the present subject matter to provide a fire-resistant battery pack which prevents the propagation of thermal runaways occurring in battery packs.
[00021] To this end, the present subject matter provides a battery pack with a battery cover composed of fire-resistant material to prevent the propagation of fire to neighbouring components of the battery pack when the battery pack is subjected to a direct flame. The fire-resistant material of the battery pack cover achieves a confinement of fire mishaps occurring in battery packs and further prevents the occurrence of catastrophic failures in electric vehicles and other equipment where battery packs are used. The disclosed configuration of the battery pack ensures a safe operational environment where the vicinity or surroundings of the battery pack is also protected against the impacts and effects of thermal runaway occurring in the battery pack.
[00022] It is a further object of the present subject matter to provide a battery pack having a battery cover with self-extinguishing properties in the event of fire occurrence in the battery pack.
[00023] To this end, the battery cover disclosed in the present subject matter is composed of a material having self-extinguishing properties to counter thermal runaway in the battery pack when the direct flame to which the battery pack was subjected to is removed.
[00024] In an aspect, the direct flame is an open flame operational at a temperature range of over 1200°C.
[00025] Additionally, the disclosed subject matter provides the material for the battery cover of the battery pack to be thermally conductive with achieves quicker cooling of the battery pack in addressing the self-extinguishing property of the disclosed material.
[00026] In accordance with the present subject matter, the battery pack having a battery pack cover composed of a material having fire-resistant properties is configured to have a higher time threshold until which it can catch fire, when the battery pack is being subjected to a direct flame. This configuration further ensures safe operation of the battery pack in high intensity operations with a higher temperature range of operability against conventional battery packs.
[00027] Traditionally manufactured or available battery packs have a low time threshold of catching fire when subjected to a direct flame with a high propensity of propagation of the flame to adjacent or neighbouring components leading to catastrophic failures.
[00028] In contrast, owing to the configuration of the present subject matter disclosing a battery pack with a battery pack cover composed of fire-resistant material having a higher time threshold until it can catch fire upon being subjected to a direct flame, the present subject matter further reduces the probability of thermal runaway occurring in the battery pack. To this regard, the durability, optimal functionality and the life cycle of the battery pack is substantially improved which would subsequently reduce the maintenance and service cost associated with the battery pack.
[00029] The present subject matter additionally discloses the battery pack provided with a battery cover to be configured to absorb mechanical shocks which in turn protects the battery pack against collision, impact and vibrational loads which the battery pack may be subjected to during its operation. The disclosed configuration of the present subject matter further improves the durability and life cycle of the battery pack.
[00030] Further, conventional battery packs have battery covers made of metal casings which lead to excess weight of the entire battery pack and increase in associated material and component costs. The present subject matter discloses a battery pack with a battery cover made of a composed material configured to possess adequate mechanical strength to absorb mechanical shocks and also provide the advantage of being light weighted.
[00031] Owing to the above-mentioned configuration of the disclosed invention, the battery pack provides a safe operational environment by possessing fire-resistant and self-extinguishing properties with mechanical strength.
[00032] Further, the present subject matter disclosing a fire-resistant battery pack and method for manufacture of the battery pack can be implemented in existing battery packs without the requirement of additional components.
[00033] In accordance with this configuration, the additional advantage of the present subject matter is the flexibility of manufacture variants in forms of size, capacity of the battery pack and ease of manufacturability. The present invention enables modified versions of the existing battery packs with minimal changes in the battery pack design, the battery cover design and even manufacturing set-up without major revamping of the core processes.
[00034] 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.
[00035] Figure 1 exemplarily illustrates a top perspective view of a battery pack, in accordance with some embodiment of the present disclosure.
[00036] With reference to Figure 1, 100 denotes a battery pack in an assembled version.
[00037] In an embodiment, the battery pack (100) consists of an electrical assembly of plurality of battery cells with a battery cover.
[00038] In an embodiment, the term battery pack (100) used in the present disclosure shall be construed to include any electrical equipment configured to store electrical energy and may include a plurality of battery cells, a plurality of battery modules or other forms of electrical energy storage equipment. The battery pack (100) is an energy storage device or an energy storage pack which is configured to store electrical energy and supply the stored electrical energy to an external electrical load as and when required.
[00039] In an aspect, the battery pack (100) may be rechargeable or non-rechargeable dependent on the application for which the battery pack (100) is used. The battery pack (100) has a charged and a discharged state.
[00040] In an aspect, the battery pack (100) is a rechargeable energy storage device being implemented in electric vehicles.
[00041] In an aspect, the battery pack (100) consists of a plurality of battery modules connected in series, with each battery module having a plurality of battery cells connected in parallel. In an aspect, the plurality of battery cells are disposed in one or more holders which hold the battery cells in the required position to maintain cell arrangement and cell spacing. The battery pack (100) includes one or more interconnectors which establish an electrical connection between the plurality of battery cells disposed in a battery module. The plurality of battery cells is welded to the interconnector to form the battery module of the battery pack.
[00042] In an embodiment, the battery pack (100) includes a battery management system (BMS) and other suitable circuitry interfaces, and/or code that is configured to work in cooperation with the battery pack (100). In an aspect the battery pack (100) includes a plurality of temperature sensors.
[00043] In an aspect, the battery pack may be configured to include a memory which may be implemented based on a Random Access Memory (RAM), a Read-Only Memory (ROM), a Hard Disk Drive (HDD), a storage server, and/or a Secure Digital (SD) card for storing battery pack related parameters.
[00044] Figure 2 exemplarily illustrates an exploded top perspective view of a battery pack, in accordance with some embodiments of the present disclosure.
[00045] With reference to figure 2, 202 denotes a right half of a centre cover for the battery pack (100), 204 denotes a top cover for the battery pack (100), 206 denotes an electrical assembly of a plurality of battery cells forming the battery pack, 208 denotes a left half of a centre cover for the battery pack (100) and 210 denotes a bottom cover for the battery pack (100).
[00046] In an embodiment, the electrical assembly (206) made of the plurality of battery cells forming the battery pack (100) is provided with a battery cover.
[00047] In an aspect, the battery cover comprises of a top cover (204), a bottom cover (210) and a centre cover (202, 208) formed by joining of the left half (208) centre cover with the right half (202) centre cover.
[00048] In an embodiment, the electrical assembly (206) of the plurality of battery cells are made to form the battery pack (100). The electrical assembly (100) is then provided with a right half (202) of a centre cover and a left half (208) of a centre cover which upon sealing from the sides form the centre cover (202, 208). The electrical assembly (100) is then provided with a top cover (204) and a bottom cover (210).
[00049] In an embodiment, the electrical assembly (206) comprises of a plurality of battery cells or a plurality of battery modules which are configured to store electrical energy. The stored electrical energy is then supplied to a connected electrical load on demand.
[00050] In an embodiment, the top cover (204), the bottom cover (210) and the centre cover (202, 208) are sealed along the edges to form a battery cover for the battery pack.
[00051] In an aspect, the battery cover consisting of a top cover (204), a bottom cover (210) and a centre cover (202, 208) protects the battery pack (100) from the external environment which includes protecting the battery pack against external impact forces during the operation of the battery pack (100).
[00052] In an aspect, the centre cover (202, 208) of the battery pack is composed of aluminum.
[00053] In an aspect, the bottom cover (210) of the batter pack is composed of a material which has fire-resistance and self-extinguishing properties. The material used for the bottom cover (210) is at least one of a first combination, a second combination and a third combination.
[00054] In an aspect, the material used for bottom cover (210) additionally includes a non-halogen flame retardant compound in conjunction with at least one of the first combination, the second combination and the third combination used to compose the material.
[00055] In an aspect, the non-halogen frame retardant compound added to the material shall ascribe for at least 5% to 40% by weight of the material being used for bottom cover (210).
[00056] In an aspect, the first combination of material used for the bottom cover (210) of the battery pack (100) is of polypropylene and long glass fibre.
[00057] In an aspect, the first combination of material comprises of at least 60% of polypropylene by weight of said material and at least 30% long glass fibre by weight of the material. Additionally, 10% of non-halogen flame retardant compound by weight of the material is added to the first combination.
[00058] In an aspect, the first combination includes at least 60% of polypropylene by weight of the material used for composing the bottom cover (210) of the battery pack (100). Polypropylene is a thermoplastic polymer formed from polymerization process from a monomer propylene. Polypropylene is configured to possess good mechanical strength and heat-resistance properties.
[00059] In an aspect, the first combination includes at least 30% of long glass fibre by weight of the material used to compose the bottom cover (210) of the batter pack (100). The long glass fibre is added to the polypropylene in the first combination as reinforcement to the polypropylene which improves the mechanical strength of the first combination.
[00060] In an aspect, the long glass fibre includes any glass fibre added to the first combination of material for the bottom cover (210) which has a designated length in the range of 10mm to 12mm and a designated diameter in the range of 2 micron to 25 micron.
[00061] In an aspect, the first combination of polypropylene and long glass fibre with non-halogen flame retardant compound has ease of processing, self-extinguishing and fire resistance properties.
[00062] In an aspect, the second combination of material used for the bottom cover (210) of the battery pack (100) comprises of polycarbonate and acrylonitrile butadiene styrene.
[00063] In an aspect, the second combination of material comprises of at least 50% to 90% polycarbonate by weight of the material, at least 10% to 50% acrylonitrile butadiene styrene by weight of the material; and at least 5% said non-halogen flame retardant compound by weight of the material.
[00064] In an aspect, the second combination comprises a higher percentage of polycarbonate by weight of material than acrylonitrile butadiene styrene to achieve a cost-effective material for the bottom cover (210) of the battery pack.
[00065] In an aspect, polycarbonate used in the second combination is an amorphous plastic having material properties such as toughness and heat-resistance.
[00066] In an aspect, acrylonitrile butadiene styrene used in the second combination is an amorphous plastic which provides material properties such as ductility and processibility.
[00067] In an aspect, polycarbonate and acrylonitrile butadiene styrene are amorphous plastic which are alloyed to enhanced processability. The blend of polycarbonate and acrylonitrile butadiene styrene are additionally provided with non-halogen flame retardant compound to increase flame retardancy of the material formed by the second combination.
[00068] In an aspect, the second combination of polycarbonate and acrylonitrile butadiene styrene have demonstrated through test results for possessing high tensile yield strength, higher elongation at break percentage and high Izod impact strength.
[00069] In an aspect, the second combination of polycarbonate and acrylonitrile butadiene styrene with non-halogen flame retardant compound additionally possess fire resistance properties and self-extinguishing properties.
[00070] In an aspect, the third combination of material used for the bottom cover (210) of the battery pack (100) comprises of polyphenylene ether, polystyrene and glass fibre.
[00071] In an aspect, the third combination of material for the battery cover comprises of at least 60% to 95% polyphenylene ether by weight of the material; at least 5% to 40% polystyrene by weight of the material; at most 10% glass fibre by weight of the material; and at least 5% said non-halogen flame retardant compound by weight of the material.
[00072] In an aspect, polyphenylene ether is a polymer formed from a reaction of an alkali-metal phenate with a halogenated benzene, the reaction being catalyzed by copper.
[00073] In an aspect, the third combination comprises of polyphenylene ether which is an amorphous thermoplastic. Polyphenylene ether has a high glass transition temperature of 215°C and possesses thermal and oxidative stability properties. However, polyphenylene ether has poor molten flowability and associated processing difficulties
[00074] In an aspect, the polystyrene used in the third combination is a high impact polystyrene. Polystyrene is formed by subjecting the monomer styrene to a polymerization process. Polystyrene is a thermoplastic.
[00075] In an aspect, polystyrene is added to the third combination comprising of polyphenylene ether, polystyrene and glass fibre to improve the processability and workability of the polyphenylene ether added in the third combination.
[00076] In an aspect, glass fibre is added to the third combination of polyphenylene ether, polystyrene and glass fibre to improve the tensile strength and dimensional stability of the material.
[00077] In an aspect, the third combination of of polyphenylene ether, polystyrene and glass fibre demonstrates material properties such as good surface appearance, high ductility and good impact resistance properties.
[00078] In an aspect, the third combination of of polyphenylene ether, polystyrene and glass fibre additionally possess material properties such as low moisture absorption, creep resistance, dimensional stability and hydrolytic stability.
[00079] In an aspect, the third combination of polyphenylene ether, polystyrene and glass fibre with non-halogen flame retardant compound additionally possess fire resistance properties and self-extinguishing properties.
[00080] In an aspect, the material used for bottom cover (210) additionally includes a non-halogen flame retardant compound in conjunction with at least one of the first combination, the second combination and the third combination used to compose the material.
[00081] In an aspect, the non-halogen flame retardant compound added to the material shall ascribe for at least 5% to 40% by weight of the material being used for bottom cover (210).
[00082] In an aspect, non-halogen flame retardant compound is added to the material comprising of at least one of the first combination, the second combination and the third combination to improve flame resistance properties of the material used in the battery cover. Non-halogen flame retardant compound is configured to be non-toxic and do not release any toxic gases during its combustion.
[00083] In an aspect, the non-halogen flame retardant is at least one of an inorganic flame retardant, a nitrogen-based flame retardant and a phosphorous-based flame retardant.
[00084] In an aspect, inorganic flame retardant includes at least aluminium hydroxide and antimony trioxide.
[00085] In an aspect, nitrogen-based flame retardants include melamine cyanurate.
[00086] In an aspect, phosphorous-based flame retardants includes at least red phosphorus and triphenyl phosphate.
[00087] In an aspect, the bottom cover (210) of the battery pack (100) of the present subject matter is composed of aluminium.
[00088] In an aspect, the bottom cover (210) being composed of a material disclosed in the present subject matter has fire-resistant properties along with self-extinguishing properties.
[00089] In operation, the battery cover composed of a material comprising of at least the first combination, the second combination and the third combination with non-halogen flame retardant compound possess exceptional fire resistance and self-extinguishing properties. The battery cover composed of the material as disclosed in the present subject matter further is in adherence with the fire resistance test.
[00090] The fire resistance test is developed as per component level testing for safety of battery packs operational in EVs. The fire resistance test involves 60 seconds of pre-heating of the battery pack followed by 70 seconds of direct exposure of the battery pack to a flame and is concluded with the battery pack being subjected to 60 seconds of indirect exposure to flame. Such a test verifies the resistance of the Rechargeable Electrical Energy Storage System (REESS) against exposure to fire from outside of the vehicle to allow the driver and passengers enough time for evacuation.
[00091] Figure 3 exemplarily illustrates a top perspective view of a battery back cover as per an embodiment of the present invention.
[00092] A person with ordinary skills in the art will appreciate that the systems, modules, and sub-modules have been illustrated and explained to serve as examples and should not be considered limiting in any manner. It will be further appreciated that the variants of the above disclosed system elements, modules, and other features and functions, or alternatives thereof, may be combined to create other different systems or applications.
[00093] Figure 4 exemplarily illustrates a flowchart depicting the process of manufacture of the battery pack, in accordance with some embodiments of the present disclosure.
[00094] The method 400 is being implemented in foundry unit having suitable machinery and equipment for manufacture of the battery cover for the battery pack as disclosed in the present subject matter. The method starts at step 402 and proceeds to step 404 where a mould is created for the battery cover of a battery pack. The mould is created for each of the parts of the battery cover which is the top cover, the bottom cover and the centre cover of the battery pack. In an embodiment, the mould for the battery pack covers are constructed from hardened steel, or pre-hardened steel, beryllium-copper alloy or other forms of metal alloys found suitable for the present application. The construction material for the mould is chosen from the category of metal alloys which have a good resistance to high temperature, less wear resistance and high hardness to overcome the economic cost associated with the creation of the mould. In an embodiment, the mould created in step 404 consists of two parts – one being an injection plate having a channel through which molten material is capable of flowing and a second part being an ejection palate having allocated ejector pins for smooth removal of the part formed. In an aspect, the injection plate and the ejector plate in an assembly form the contour of the battery pack cover.
[00095] At step 406, a material for forming the battery cover of the battery pack is synthesized by alloying at least one of a first combination, a second combination and a third combination of material in conjunction with a non-halogen flame retardant. In an aspect, the non-halogen flame retardant ascribes for at least 5% to 40% by weight of the material being used for forming the battery cover of the battery pack.
[00096] In an aspect, the first combination of material used for battery cover is synthesized by alloying polypropylene and long glass fibre. In an aspect, the first combination of material comprises of at least 60% of polypropylene by weight of said material alloyed with at least 30% long glass fibre by weight of the material. Additionally, 10% of non-halogen flame retardant compound by weight of the material is added to the first combination.
[00097] In an aspect, the second combination of material used for the battery cover is synthesized by alloying polycarbonate and acrylonitrile butadiene styrene. In an aspect, the second combination is synthesized by alloying at least 50% to 90% polycarbonate by weight of the material with at least 10% to 50% acrylonitrile butadiene styrene by weight of the material. Additionally, at least 5% of the non-halogen flame retardant compound by weight of the material is added to the second combination of material.
[00098] In an aspect, the third combination of material used for the battery cover of a battery pack is synthesized by alloying a combination of polyphenylene ether, polystyrene and glass fibre. In an aspect, the third combination of material comprises of at least 60% to 95% polyphenylene ether by weight of the material being alloyed with at least 5% to 40% polystyrene by weight of the material and at most 10% glass fibre by weight of the material. Additionally, at least 5% said non-halogen flame retardant compound by weight of the material is added to the third combination to synthesize the material for the battery cover of the battery pack.
[00099] In an aspect, the first combination, the second combination and the third combination of material synthesized for the battery cover of a battery pack kas fire resistance and self-extinguishing properties.
[000100] At step, 408 a molten form of the synthesized material is injected into the mould created in step 404. The mould is in an assembly with a channel inserted in the injection plate of the mould to allow the molten form of the synthesized material to flow into the mould cavity. The material synthesized by alloying of at least one of the first combination, the second combination and the third combination with non-halogen flame retardant compound is transferred to a heating unit. The heating unit is configured to heat the synthesized material such that a molten form of the synthesized material is achieved.
[000101] In an aspect, the first combination of synthesized material comprising of polypropylene and long glass fibre with non-halogen flame retardant compound is procured in molten form by heating the first combination at a temperature range of 220°C to 280°C.
[000102] In an aspect, the second combination of synthesized material comprising of polycarbonate and acrylonitrile butadiene styrene with non-halogen flame retardant compound is procured in molten form by heating the second combination at a temperature range of 120°C to 270 °C.
[000103] In an aspect, the third combination of synthesized material comprising of polyphenylene ether, polystyrene and glass fibre with non-halogen flame retardant compound is procured in molten form by heating the third combination at a temperature range of 320 °C to 400°C.
[000104] In an aspect, at step 408 the molten form of the synthesized material is injected under high pressures to the created mould through a nozzle. In an embodiment, the molten form of the synthesized material stored in the heating unit is transferred to the created mould through a ram or screw type plunger which forces the molten form of the synthesized material at high pressures into the mould.
[000105] In an aspect, the ram or screw type plunger includes a checking unit that is configured to ensure that the molten form of the synthesized material flows into the mould at a constant flow rate. The checking unit further ensures that the molten form of the synthesized material flowing into the mould is not supplied beyond the designated capacity of the mould to prevent any over spill in the vicinity of the mould. In an aspect, the checking unit ensures no amount of the synthesized material is wasted.
[000106] In an embodiment, the checking unit may contain suitable logical, arithmetic and electrical or electronic circuitry interfaces and/or code in configuring the appropriate volume of the molten synthesized material which is to be supplied to the mould. The checking unit may also contain a control unit with a memory chip being configured to effectively execute the function of the checking unit.
[000107] In an aspect, the checking unit may be configured to include a memory which may be implemented based on a Random Access Memory (RAM), a Read-Only Memory (ROM), a Hard Disk Drive (HDD), a storage server, and/or a Secure Digital (SD) card.
[000108] At step 410, the molten form of the synthesized material poured into the created mould is allowed to cool and harden. In an aspect, the cooling of the synthesized material in the created mould alloys the synthesized material to conform to the contours of the mould.
[000109] In an aspect, a clamping unit is provided to the created mould to ensure that the injection plate and ejection plate of the created mould are tightly held in place allowing minimal dimensional inaccuracies in the manufactured battery cover for the battery pack.
[000110] At step 412, the manufactured battery cover formed after hardening of the synthesized material inside the mould is ejected from the created mould using ejector pins or other equivalent mechanisms installed in the ejection plate of the created mould for securely removing the manufactured battery cover of the battery pack from the mould. The method 400 ends at step 414.
[000111] 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.
[000112] The disclosed claimed limitations and the disclosure provided herein provides a fire resistant battery pack and a method of manufacture of the battery pack. The claimed invention in an aspect provides enhanced environmental safety by ascribing self-extinguishing and fire resistance properties to the battery pack disclosed in the present subject matter.
[000113] In an aspect, the material synthesized for the battery cover of a battery pack prevents the propagation of fire occurring in battery pack to neighbouring components. In an aspect, the fire resistant battery pack has longer time threshold in catching fire when the battery pack is exposed to a direct flame having a temperature of over 1200°C. The fire resistant battery pack in restricting the propagation of fire leads to confinement of fire mishaps which often lead to catastrophic failures in systems employing battery packs. Thus, the disclosed subject matter promotes a safer environment for operation of systems employing battery packs.
[000114] Conventional battery packs carry a disclosure where they are strictly prohibited to be subjected to direct flames, which tremendously reduces the scope of application of conventional battery packs in high temperature operations.
[000115] In an aspect, the battery pack having a battery cover made of the synthesized material has a longer time threshold in catching fire when subjected to a direct flame of over 1200°C, this allows the battery pack to be deemed to be suitable in applications involving higher temperature ranges of operation.
[000116] In an aspect, the occurrence of thermal runaway in batteries is an inevitable phenomenon and conventional battery packs are not equipped with mechanisms to counter thermal runaway. The present subject matter discloses a battery pack with self-extinguishing properties which effectively alleviate the issues arising from occurrence of thermal runaways. Consequently, the durability and life cycle of the battery pack is improved.
[000117] In an aspect, the synthesized material for the battery cover adheres to the Rechargeable Electrical Energy Storage System (REESS) against exposure to fire from outside of the vehicle, warranting passengers of the vehicle enough time for evacuation from the vehicle in the event of fire. In an aspect, the REESS is a component level testing of the battery pack where the battery pack is first subjected to 60 seconds of pre-heating followed by 70 seconds of direct exposure to a flame. After 70 seconds of exposure to direct flame, the battery pack is subjected to 60 seconds of indirect exposure to the flame.
[000118] In an aspect, the disclosed battery pack with a battery cover made of the synthesized material possesses high mechanical strength to absorb mechanical shocks when the battery pack is subjected to impact or vibrational loads. In an aspect, high mechanical strength of the battery configures the battery pack to be durable against operational wear and tear.
[000119] In an aspect, the disclosed subject matter provides a battery cover for a battery pack composed of a synthesized material configured to have a light weight, thereby reducing the overall weight of the battery pack. Conventional battery packs with metal casings as battery covers have a redundant weight and component cost associated with the overall battery pack assembly.
[000120] In light of the above-mentioned advantages and the technical advancements provided by the disclosed method of manufacture of the battery pack and the fire-resistant battery pack, the claimed steps 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. Further, the claimed steps clearly bring an improvement in the functioning of the battery pack itself as the claimed steps provide a technical solution to a technical problem.
[000121] A description of an embodiment with several components in communication with another does not imply that all such components are required, On the contrary, a variety of optional components are described to illustrate the wide variety of possible embodiments of the invention,
[000122] Finally, the language used in the specification has been principally selected for readability and instructional purposes, and it may not have been selected to delineate or circumscribe the inventive subject matter and is therefore intended that the scope of the invention be limited not by this detailed description, but rather by any claims that issue on an application based here on. Accordingly, the embodiments of the present invention are intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the following claims.
[000123] While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.
[000124] A person with ordinary skills in the art will appreciate that the systems, modules, and sub-modules have been illustrated and explained to serve as examples and should not be considered limiting in any manner. It will be further appreciated that the variants of the above disclosed system elements, modules, and other features and functions, or alternatives thereof, may be combined to create other different systems or applications.
[000125] While the present disclosure has been described with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the present disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from its scope. Therefore, it is intended that the present disclosure not be limited to the particular embodiment disclosed, but that the present disclosure will include all embodiments falling within the scope of the appended claims.
 

List of Reference numerals
100: Battery pack
202: Battery right side cover
204: Battery top cover
206: Electrical assembly of plurality of battery cells
208: Battery left side cover
210: Battery bottom cover

, Claims:We claim:
1. A battery pack, said battery pack comprising:
a battery cover, said battery cover comprising of at least a top cover, a bottom cover and a centre cover, wherein said top cover and said centre cover being made of aluminium and bottom cover being composed of a material, said material being at least one of:
a first combination of polypropylene and long glass fibre; or
a second combination of polycarbonate and acrylonitrile butadiene styrene; or
a third combination of polyphenylene ether, polystyrene and glass fibre; and
wherein said material comprises a non-halogen flame retardant compound, wherein said non-halogen flame retardant compound being at least 5% to 40% by weight of said material.
2. The battery pack as claimed in claim 1, wherein said bottom cover being made of Aluminium.
3. The battery pack as claimed in claim 1, wherein said material being a fire-resistant material.
4. The battery pack as claimed in claim 1, wherein said material comprising of said first combination comprising of
at least 60% polypropylene by weight of said material;
at least 30% long glass fibre by weight of said material; and
10% said non-halogen flame retardant compound by weight of said material.
5. The battery pack as claimed in claim 1, wherein said long glass fibre being of length of 10mm to 12mm.
6. The battery pack as claimed in claim 1, wherein said material comprising of said second combination comprising of:
at least 50% to 90% polycarbonate by weight of said material;
at least 10% to 50% acrylonitrile butadiene styrene by weight of said material; and
at least 5% said non-halogen flame retardant compound by weight of said material.
7. The battery pack as claimed in claim 1, wherein said material comprising of said third combination comprising of
at least 60% to 95% polyphenylene ether by weight of said material;
at least 5% to 40% polystyrene by weight of said material;
at most 10% glass fibre by weight of said material; and
at least 5% said non-halogen flame retardant compound by weight of said material.
8. The battery pack as claimed in claim 1, wherein said third combination includes a high impact polystyrene.
9. The battery pack as claimed in claim 1, wherein said non-halogen flame retardant being at least one of
an inorganic flame retardant;
a nitrogen-based flame retardant; and
a phosphorous-based flame retardant.
10. A method for manufacturing a battery pack, said method comprising steps of:
creating, a mould for each of a top cover, a bottom cover and a centre cover, wherein said top cover, said bottom cover and said centre cover together form a battery cover for said battery pack;
synthesizing, a material for said battery cover, said material being composed by alloying at least one of:
a first combination of polypropylene and long glass fiber,
a second combination of polycarbonate and acrylonitrile butadiene styrene, and
a third combination of polyphenylene ether, polystyrene and glass fibre,
wherein said material comprises a non-halogen flame retardant compound, wherein said non-halogen flame retardant compound being at least 10% to 40% by weight of said material;
injecting, a molten form of said synthesized material into said mould for forming said battery cover;
cooling, said mould of said battery cover to allow hardening of said molten form of said material; and
ejecting, said battery cover from said mould.
11. The method for manufacture of said battery pack as claimed in claim 10, wherein said synthesized material of said first combination, said second combination and said third combination being subjected to a temperature range of 120-320 degree Celsius to form said molten form of said synthesized material.