DESC:FIELD OF INVENTION
[0001] The embodiments herein generally relate to battery systems and more particularly for providing a thermal conductive enclosure for dissipating heat generated by a plurality of cells. The present application is based on, and claims priority from an Indian Application Number 3496/CHE/2014 filed on 16th July, 2014, the disclosure of which is hereby incorporated by reference herein.
BACKGROUND OF THE INVENTION
[0001] Generally, battery power supplies have been well established and the packaging together of a plurality of cells in a parallel or series configuration to form a battery pack for using as a power supply for personal electronic devices such as cell phones, laptop computers, etc. are well-known and common. Further, desirable properties or characteristics of the battery power supplies including, for example, the capability of certain battery power supplies to be quickly recharged makes such battery power supplies an attractive power source for vehicle propulsion, i.e., electric vehicles (EV). In most cases, the battery packs need thermal management as the heat accumulates and causes aging of cells within the battery.
[0002] In the conventional systems, the electric vehicles using electric power for a portion of their motive force may derive their power from multiple individual battery cells which are packed into the battery modules. Further, the battery module contains multiple cells within housing. As the individual cells are charged and discharged, they generate heat due to joule heating caused by the current flowing through internal resistance. In addition, the individual cells are subjected to heating via exothermic chemical reactions occurring within the cells.
[0003] Further, the elevated ambient temperatures add heat to the cells via conduction, convection, or radiation. The sources of thermo-electrical, thermo-chemical, and environmental heating may cause increased localized temperatures of the cells. The increase in the temperature may be aggravated by the tight packaging of the multiple cells within confined space of the battery pack housing. The increased temperatures may increase the rate of chemical reactions thereby, causing failure modes (i.e., internal short circuits).
[0004] In another conventional battery systems relying on air cooling, additional filters or heat exchangers need to be incorporated for thermal management of the battery pack. Additionally, internal connections and the cells need to be coated with protective materials to prevent failures due to entry of the moisture and dust through the additional filters or heat exchangers.
[0005] Further, the air needs to be routed from the fans installed in the vehicle or from vents located in the vehicle. Thus, adding complexity to the battery pack design, since it increases the number of interfaces and size of the battery pack, adversely affecting assembly and regular maintenance of the battery pack.
[0006] Thus, there is a need in the art to for a simple and robust battery system to provide an effective cooling system to draw excess heat away from the battery system, thereby creating a safe and uniform temperature distribution along the cells in the battery system.
[0007] The above information is presented as background information only to help the reader to understand the present invention. Applicants have made no determination and make no assertion as to whether any of the above might be applicable as Prior Art with regard to the present application.

OBJECT OF INVENTION
[0008] The principal object of the embodiments herein is to provide a battery system including a thermal conductive enclosure, a plurality of cells disposed in the thermal conductive enclosure, a plastic body placed on the plurality of cells in the thermal conductive enclosure, and one or more fans attached to the plastic body. The thermal conductive enclosure to dissipate heat out of the air circulated around the plurality of cells disposed in the thermal conductive enclosure.
[0009] Another object of the embodiments herein is to provide a battery system including a thermal conductive enclosure which can be exposed to ambient environment to continuously dissipate the heat away from the battery system.
[0010] Another object of the embodiments herein is to provide a battery system including a thermal conductive enclosure coated with thermal conductivity material to increase thermal conductivity properties of said thermal conductive enclosure to continuously dissipate the heat away from the battery system.
[0011] Another object of the embodiments herein is to provide a battery system including an airtight thermal conductive enclosure to block the moisture and dust particles entering into the battery system.
[0012] Another object of the embodiments herein is to a mechanism for guiding air from the fans through gaps between the pluralities of cells in the thermal conductive enclosure to cool the battery system.
[0013] Another object of the embodiments herein is to a mechanism for sucking back the air around the cells due to draft created by the fans causing the air to flow turbulently along walls of the thermal conductive enclosure. The thermal conductive enclosure dissipates the heat out of the air flowing turbulently along the walls.
[0014] Another object of the embodiments herein is to provide a battery system including a mechanism for powering the various fans disposed in the thermal conductive enclosure using internal wiring system.
SUMMARY
[0015] Accordingly the embodiments herein provide a battery system. The battery system includes a thermal conductive enclosure, a plurality of cells disposed in the thermal conductive enclosure, a plastic body placed on the plurality of cells in the thermal conductive enclosure, wherein the plastic body acts as a holding structure for the plurality of cells, and at least one fan attached to the plastic body. The at least one fan for driving air onto the plurality of cells and the thermal conductive enclosure dissipates heat out of the air circulated around the plurality of cells.
[0016] In an embodiment, the plastic body guides the air from the at least one fan through gaps between the plurality of cells in thermal conductive enclosure.
[0017] In an embodiment, the air is guided along at least one of a longest face and a widest face of each the cell to attain maximum contact area.
[0018] In an embodiment, the air is sucked back due to draft created by the at least one fan causing the air to flow turbulently along walls of thermal conductive enclosure, the thermal conductive enclosure dissipates the heat out of the air flowing turbulently along the walls.
[0019] In an embodiment, the thermal conductive enclosure is exposed to ambient environment to continuously dissipate the heat.
[0020] In an embodiment, the thermal conductive enclosure is coated with thermal conductivity material to increase thermal conductivity properties of thermal conductive enclosure.
[0021] In an embodiment, the at least one fan are powered by the plurality of cells with internally contained wiring.
[0022] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.
BRIEF DESCRIPTION OF FIGURES
[0023] This invention is illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:
[0024] FIG. 1 shows a battery system with a transparent view of a thermal conductive enclosure for dissipating heat out of air circulated around a plurality of cells, according to embodiments as disclosed herein;
[0025] FIG. 2 shows a basic arrangement inside the thermal conductive enclosure for dissipating heat out of air circulated around the plurality of cells, according to embodiments as disclosed herein;
[0026] FIG. 3 shows an example top view of the battery pack for dissipating heat out of air circulated around a plurality of cells, according to embodiments as disclosed herein; and
[0027] FIG. 4 shows another example side view of the battery pack for dissipating heat out of air circulated around a plurality of cells, according to embodiments as disclosed herein.

DETAILED DESCRIPTION OF INVENTION
[0028] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. Also, the various embodiments described herein are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments. The term “or” as used herein, refers to a non-exclusive or, unless otherwise indicated. The examples used herein are intended merely to facilitate understanding of ways in which the embodiments herein can be practiced and to further enable those skilled in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0029] The embodiments herein disclose a battery system. The battery system includes a thermal conductive enclosure, a plurality of cells disposed in the thermal conductive enclosure, a plastic body placed on the plurality of cells in the thermal conductive enclosure, wherein the plastic body acts as a holding structure for the plurality of cells, and at least one fan attached to the plastic body. The at least one fan for driving air onto the plurality of cells and the thermal conductive enclosure dissipates heat out of the air circulated around the plurality of cells.
[0030] Further, the plastic body guides the air from the at least one fan through gaps between the plurality of cells in the thermal conductive enclosure. The air is guided along a longest face or a widest face of each cell to attain maximum contact area.
[0031] In an embodiment, the air is sucked back due to draft created by the at least one fan causing the air to flow turbulently along walls of the thermal conductive enclosure, wherein the thermal conductive enclosure dissipates heat the heat out of the air flowing turbulently along the walls.
[0032] In an embodiment, the thermal conductive enclosure is exposed to ambient environment to continuously dissipate the heat.
[0033] In an embodiment, the thermal conductive enclosure is coated with thermal conductivity material to increase thermal conductivity properties of the thermal conductive enclosure.
[0034] In an embodiment, the at least one fan are powered by the plurality of cells with internally contained wiring.
[0035] In the conventional systems, electrochemical batteries generate heat due to electrical resistance and internal electrochemical processes. In most cases, battery system need thermal management as the heat accumulates and causes aging of the cells within the battery.
[0036] In the conventional systems, air is utilized as the coolant within the cooling system. Typical thermal management or cooling systems may use additional elements such as coolants, filter, heat exchanges or the like to dissipate heat away from the battery system. The usage of such components may result in increased weight, complexity, installation space, cost, or the like parameters of the overall battery system.
[0037] Unlike the conventional systems, the proposed battery system include a thermal conductive enclosure used for multiple functions. The thermal conductive enclosure serves as a housing for the lithium ion cells, Battery Management System and some other parts. It also acts the heat exchanger which draws heat out of the air that is circulated around the cells. Unlike the most forced air convention systems, where they have a separate air tight housing and another metal structure for the heat exchanger, the proposed battery system integrates functionalities in the thermal conductive enclosure thereby reducing overall battery system assembly complexity, installation space, weight, and costs.
[0038] Unlike the conventional systems, the plastic body has two functions. First, its acts as a guide for routing the air from the fans through the gaps between the cells, for cooling. Second, it acts as a holding structure for the lithium ion cells inside the thermal conductive enclosure. Further, the proposed battery system for thermal management provide an effective cooling mechanism with minimal wastage of space and without using additional the elements. Furthermore, the proposed battery system can be implemented using existing infrastructure and may not require exhaustive set up and instrumentations.
[0039] Referring now to the drawings, and more particularly to FIGS. 1 through 4, where similar reference characters denote corresponding features consistently throughout the figures, there are shown preferred embodiments.
[0040] FIG. 1 shows a battery system 100 with a transparent view of a thermal conductive enclosure 102 for dissipating heat out of air circulated around a plurality of cells 108, according to embodiments as disclosed herein. In an embodiment, the thermal conductive enclosure 102 includes the plurality of cells 108, one or more fans 108 mounted in the thermal conductive enclosure 102, and a plastic body 106 that act as a guide to route air in a right direction and is placed just below the one or more fans 108. In an embodiment, the one or more fans 108 can be, for example but not limited to, centrifugal fans, axial fans, and Direct current (DC) fans, and Alternating current (AC) fans. Unlike conventional systems, the fans do not need external power and are powered by the plurality of cells 108 with internally contained wiring. This reduces another typical interface that the battery system 100 would have had with the vehicle. A lower number of interfaces improve the assembly, maintenance and safety of the battery system 100.
[0041] Further, in the thermal conductive enclosure 102, the fans 108 are placed vertically above the plurality of cells 108 to force the air onto the surface of the plurality of cells 108. The thermal conductive enclosure 102 is exposed to ambient environment which will continuously dissipate the heat generated by the plurality of cells 108. In an embodiment, the thermal conductive enclosure 102 can be coated, painted, or treated with appropriate materials ensuring that the thermal conductive enclosure 102 body does not have significant electrical conductivity but has high thermal conductivity. Thus, allowing for easier packaging of all components within the thermal conductive enclosure 102 while still ensuring a low failure rate due to electrical shorts.
[0042] Unlike conventional systems, where they have a separate air tight housing and another metal structure for the heat exchanger, the properties of the thermal conductive enclosure enable it to act as the heat exchanger which draws heat out of the air that is circulated around the cells. In an embodiment, the thermal conductive enclosure 102 is an airtight thermal conductive enclosure. As the thermal conductive enclosure 102 is airtight, it does not let the ambient air to enter inside the thermal conductive enclosure 102 thereby blocking the entry of moisture or foreign particles leading to catastrophic events such as electrical shorts and battery fires. Additionally, internal connections and the cells need not be coated with protective materials for prevent of failures as there is no additions elements such as filter, heat exchanges, coolants used to draw the heat away from the battery system.
[0043] FIG. 2 shows a basic arrangement inside the thermal conductive enclosure 102, according to embodiments as disclosed herein. In an embodiment, if the battery system 100 is being charged or discharged then there will be continuous heating of the plurality of cells 108 and other components inside the thermal conductive enclosure 102 due to electrical resistance. The plurality of cells 108 generates heat continuously when in operation. The generated heat may cause series problems, such as reduction in the life of the cells, overheating and thermal runaways that occur due to uncontrolled heating, and can cause damage to the cells and also to various electronic components in the battery system 100, if the heat is not dissipated into the environment. The life of each cell depends on its operating conditions.
[0044] In an embodiment, the coolant used is air, which is quite literally free and is effective under the right conditions. It offers good thermal properties and obviates unwanted complications in operation, such as leakage and performance degradation. The heat transfer between a solid body and a fluid occurs through convection. The amount of heat transfer is mainly based on a convection property called the heat transfer coefficient. The battery system 100 can be designed to utilize heat transfer coefficient at its maximum value by designing the air flow across the surfaces of the plurality of cells 108. The one or more fans 104 can be used to create the air flow that is turbulent throughout, causing forced convection. The air is guided along the longest and widest faces of the plurality of cells 108 to attain maximum contact area. Further, the air is then sucked back up due to the draft created by the one or more fans 104. This causes the air to flow back up turbulently along the walls of the thermal conductive enclosure 102, causing a high rate of heat transfer to the thermal conductive enclosure 102.
[0045] Further, the turbulent air flow created by the one or more fans 104 can ensure the high rate of heat transfer between the components of the battery system 100 and the air. Further, the air from the one or more fans 104 can be guided to the gaps provided between the cells 108 using the plastic body 106. The gaps are between the largest surfaces of the plurality of cells 108 thereby, providing maximum contact area for the heat transfer. The plastic body 106 is provided with curtains at the four ends to prevent the air from escaping from the sides as shown in the FIG. 2. The hot air from the bottom is sucked back to the top due to the low pressure point created at the fan inlets above. The hot air from the bottom flows upwards along the side walls of the thermal conductive enclosure 102. During this flow, the air will lose the generated heat to the thermal conductive enclosure 102, which has the high thermal conductivity. Further, the thermal conductive enclosure 102 is exposed to the ambient environment. The heat generated by the plurality of cells 108 is released to the ambient environment continuously, thereby preventing any heat accumulation inside the thermal conductive enclosure 102.
[0046] Further, the battery system 100 can be integrated into the thermal conductive enclosure 102, which is a hermetically sealed enclosure. In conventional air cooled battery packs, the ambient air flows in and out of the battery. Unlike the conventional systems, the ambient air is not allowed inside the battery system 100 thereby preventing entry of elements such as moisture and dust that can cause serious damage to the battery system 100. Electrical shorting of batteries due to the moisture condensation is a common event among exposed battery packs, unless conditioned air is being used. The simplicity of the design makes handling and examination of the battery system convenient. Complicated battery systems that use components such as radiators, are difficult to assemble and cumbersome to handle.
[0047] In an embodiment, on using a highly conductive material for the thermal conductive enclosure 102 instead of metal would improve cooling of the battery system 100 significantly.
[0048] In an embodiment, the thermal conductive enclosure 102 can be covered with material that changes phase at low temperatures. This kind of material (also known as a ‘Phase Change Material’) absorbs heat from the thermal conductive enclosure 102, without rise in temperature.
[0049] FIG. 3 shows an example top view of the battery pack 300 for dissipating heat out of air circulated around the plurality of cells, according to embodiments as disclosed herein. In an embodiment, the battery pack 300 includes a centrifugal fan, Battery management system (BMS) circuit board, BMS Metal oxide semiconductor field effect transistor (MOSFET), BMS cooling fan, inlet plenum, outlet plenum, and outlet enclosure.
[0050] Further, the centrifugal fan can be used in place of axial fans. The centrifugal fans can offer higher flow rates but are heavy and noisy. The positioning of the centrifugal fan is different from the arrangement of the fans as shown in the FIG. 2. The FIG. 3 shows the top view of the battery pack 300 which has one centrifugal fan, moving air along the length of the battery pack 300. The blower is fitted with a plenum at the inlet and outlet to guide the air along the top and bottom of the battery pack 300. The movement of the air along the top and bottom (i.e. dotted arrows) of the battery pack 300 cools the cells (i.e., Lithium ion cells) at the terminal ends and also cools the battery metal interconnects, which are heated up during operation of the cells. Since the air flow does not cover the BMS MOSFET which requires significant cooling, there is a dedicated fan for cooling the BMS MOSFET (as shown in the FIG. 3 ‘BMS cooling fan’). Separate and sufficient cooling of both systems ensures efficient operation of the battery pack 300.
[0051] FIG. 4 shows a side view of the battery pack 300 for dissipating heat out of air circulated around a plurality of cells, according to embodiments as disclosed herein. In an embodiment, the battery pack 300 includes centrifugal fan, outlet plenum, inlet plenum, and cells (for example, lithium ion cells). The air flow generated by the centrifugal fan will flow across the outer surface of the cells as shown in the FIG. 4.
[0052] The embodiments disclosed herein can be implemented through at least one software program running on at least one hardware device and performing network management functions to control the elements. The elements shown in the FIGS. 1 through 4 include blocks which can be at least one of a hardware device, or a combination of hardware device and software module.
[0053] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
,CLAIMS:What is claimed is:
1. A battery system comprising:
a thermal conductive enclosure;
a plurality of cells disposed in said thermal conductive enclosure;
a plastic body placed on said plurality of cells in said thermal conductive enclosure, wherein said plastic body act as a holding structure for said plurality of cells; and
at least one fan attached to said plastic body;
wherein said at least one fan for driving air onto said plurality of cells; and
wherein said thermal conductive enclosure dissipates heat out of said air circulated around said plurality of cells.
2. The battery system of claim 1, wherein said plastic body guides said air from said at least one fan through gaps between said plurality of cells in said thermal conductive enclosure.
3. The battery system of claim 2, wherein said air is guided along at least one of a longest face and a widest face of each said cell to attain maximum contact area.
4. The battery system of claim 2, wherein said air is sucked back due to draft created by said at least one fan causing said air to flow turbulently along walls of said thermal conductive enclosure, wherein said thermal conductive enclosure dissipates said heat out of said air flowing turbulently along said walls.
5. The battery system of claim 4, wherein said thermal conductive enclosure is exposed to ambient environment to continuously dissipate said heat.
6. The battery system of claim 1, wherein said thermal conductive enclosure is coated with thermal conductivity material to increase thermal conductivity properties of said thermal conductive enclosure.
7. The battery system of claim 1, wherein said at least one fan are powered by said plurality of cells with internally contained wiring.
Dated: 16th Day of June, 2015 Signature
Arun Kishore Narasani Patent Agent