FIELD OF INVENTION

[001] The present disclosure relates generally to a power pack, particularly a power pack with an integrated active thermal management system for an electric vehicle that is configured to provide efficient and faster cooling of the battery pack of the vehicle that reduces thermal hotspots and thermal propagation inside the Battery Pack.

BACKGROUND OF THE INVENTION

[002] Electric vehicles are rapidly gaining popularity in today's automotive marketplace as they offer economical as well as environmental benefits with several desirable features, such as eliminating pollutant emissions while having lower operating costs. With the increasing commercialization of the electric vehicles, the capacity of the battery pack used in the electric vehicles has become larger and the output voltage has become higher as they contain numerous interconnected cells, operating at a relatively high voltage, and delivering power on demand, to drive the motor of the vehicle. Maximizing battery life is a key consideration in the design and operation of electric vehicles.

[003] To enable the battery pack to perform at its fullest, it is important to hold the battery temperature at their working temperature ranges. The cells of the battery build up heat due to chemical reactions (enthalpy changes & electrochemical polarization) happening at the time of discharge and/or joule heating developed due to internal resistance of the cells to the passage of current. Due to heat generation inside the cells, the internal temperature of the battery pack rises while charging & discharging. If the temperature of the battery pack goes beyond the working temperature, its capacity reduces drastically which adversely affects the performance and range of electric vehicles. Besides, operating the battery pack outside its recommended working temperature will lead to safety concerns like catching fire, explosion, and thermal run-away phenomena. [004] To secure the battery performance, the battery has to be cooled by sufficient means. Cooling of battery by the natural flow of air was sufficient for the battery of a vehicle powered by a conventional internal combustion engine, but is slow and insufficient for cooling a high voltage battery with a voltage of 120V range or higher used in EV having a high charge & discharge rate.

[005] Many manufacturers have implemented an active thermal management system that uses forced convection as a major mode of heat rejection from the battery pack using a coolant. However, extracting heat generated inside the cells of the battery pack is still the most challenging part. The majority of the prior system relied on extracting heat from the cylindrical side faces or walls of the cells. This mode of heat extraction increases the size of the battery pack while demanding the removal of insulation to reduce thermal resistance. This creates challenges in the assembly and safety of the battery pack. It is essential to keep the temperature inside the battery pack uniform everywhere. It is also required to maintain the thermal resistance between each cell and the ambient the same, otherwise it will create hotspots inside the cell.

[006] Thus, an active thermal management system is highly desirable that can efficiently extract heat from each and every cell of the battery pack without contributing to additional weight or cost and avoids thermal hotspots and thermal propagation inside the Battery Pack.

OBJECT OF THE INVENTION

[007] It is an object of the invention to provide a power pack with an integrated active thermal management system for an electric vehicle that is configured to extract heat as well as current from each and every cell in a higher voltage battery pack.

[008] Another object of the invention is to provide a compact active thermal management system for an electric vehicle that is configured to extract heat as well as current from each and every cell in the higher voltage battery pack without adding additional weight or size of the battery pack. [009] Yet another object of the invention is to provide an active thermal management system for an electric vehicle that provides faster cooling of each and every cell in a higher voltage battery pack.

[0010] Still another object of the invention is to provide an active thermal management system for an electric vehicle that avoids thermal hotspots and thermal propagation inside a higher voltage Battery Pack.

[0011 ] Other objects and advantages of the system of the present disclosure will be more apparent from the following description when read in conjunction with the accompanying figures, which are not intended to limit the scope of the present disclosure.

SUMMARY OF THE INVENTION

[0012] In one embodiment of the present invention, a power pack with an integrated active thermal management system for an electric vehicle is provided. The system comprises a plurality of battery packs, a cooling circuit, and a Battery Pack Thermal Management System. Each of the battery pack comprises a cell array comprising a plurality of single cells arranged in a closely packed configuration, a first and a second set of a plurality of heat and current collector panels in contact with the top and the bottom of the cell array respectively, a first and a second set of a plurality of heat spreaders provided at the junction of nearby heat and current collector panels at the top and the bottom of the cell array respectively, a first and a second thermal pad in contact with the first and the second set of the plurality of heat spreaders respectively, a cooling plate in contact with the first thermal pad and is comprising an inlet and an outlet for a coolant, and an L-Shaped heat spreader in contact with the second thermal pad.

[0013] In an embodiment of the invention, each of the heat and current collector panels comprises a first plate made of a first material containing a plurality of circular openings and a second plate made of a second material containing a plurality of trapezoidal projections formed thereon at a position corresponding to the circular openings of the first plate. Each opening has a first width (W1 ). [0014] Here, each of the trapezoidal projections has a top flat face having a second width, and a side wall extending downwardly from the top face toward a base of the projection having a third width.

[0015] In a preferred embodiment of the invention, the second width is smaller than the third width and the third width is equal to the first width.

[0016] The cooling circuit comprising a coolant pump configured to circulate a coolant inside the cooling plate of the battery pack.

[0017] In one embodiment of the invention, the Battery Pack Thermal Management System is configured to dynamically control cooling of the cell array based on at least one of the battery pack conditions, cooling circuit conditions, ambient conditions and driving mode of the electric vehicle. The Battery Pack Thermal Management System comprises at least one temperature sensors configured to sense the temperature of at least one of the coolant, atmosphere and, battery pack, at least one of flow rate sensors configured to sense flow rate of the coolant pump and radiator fan, and at least one sensors for sensing vehicle driving conditions and battery pack SOC/SOH.

[0018] In a one embodiment of the invention, Battery Pack Thermal Management System is configured to dynamically control cooling of the cell array by controlling the flow rate of the coolant pump.

[0019] In a preferred embodiment of the invention, each heat and current collector panels is formed by assembling the second plate on top of the first plate in a manner that base of each of the trapezoidal projection in the second plate is aligned with the opening of the first plate.

[0020] In one embodiment of the invention, the second plate further comprises a rectangular or oval cut-out on the side face of each of the trapezoidal projections for venting gases. The heat and current collector panel are arranged over cell array in such a manner that an end terminal of each cell in the cell array is in thermal and electrical connection with the top face of the trapezoidal projections.

BRIEF DESCRIPTION OF THE DRAWINGS [0021 ] FIG. 1 shows a schematic representation of a power pack with an integrated active thermal management system according to an embodiment of the present invention.

[0022] FIG. 2 shows an exploded perspective view of a battery pack of a power pack with an integrated active thermal management system according to an embodiment of the present invention.

[0023] FIG. 3 shows a perspective isometric view of the heat and current collector panel of the battery pack of FIG. 2 according to an embodiment of the present invention.

[0024] FIG. 4a shows a cross-sectional view of a power pack with an integrated active thermal management system according to an embodiment of the present invention.

[0025] FIG. 4b shows an enlarged view of a first portion of the power pack of FIG. 4a according to an embodiment of the present invention.

[0026] FIG. 4c shows an enlarged view of a second portion of the power pack of FIG. 4a according to an embodiment of the present invention.

DESCRIPTION

[0027] Detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components.

[0028] FIG. 1 shows a schematic representation of a power pack with an integrated active thermal management system 100 (referred to as system 100 hereinafter for brevity) according to an embodiment of the present invention. System 100 comprises at least one battery pack A and a cooling circuit B.

[0029] The battery pack A comprises cell array 101 , a plurality of heat and current collector panels 102, a plurality of heat spreader 103, a thermal pad 104, a cooling plate 105, and a L-Shaped heat spreader 106. [0030] The cell array 101 comprises a series of the individual cells which are electrically and mechanically connected in a row and arranged in parallel in a closely packed configuration. In a preferred embodiment of the invention, the cell array 101 comprises cylindrical or barrel shaped cells. In a more preferred embodiment of the invention, the cell array 101 comprises at least 300 upto 6000 individual cells of 3-5 V, preferably 4.2 V. In a yet preferred embodiment of the invention, the cell array 101 comprises, but is not limited thereto, 500-550 cells, more preferably 530-535 cells. In a more preferred embodiment of the invention, the battery pack A is a high voltage battery pack, more preferably, at least 100 upto 300 kWh battery.

[0031 ] In a preferred embodiment of the invention, the plurality of heat and current collector panels 102 are arranged in a side-by-side configuration on both, a top and a bottom side of the cell array 101 over an entire length of the battery pack A. In this way, the heat and current collector panels 102 are arranged to be in contact with any one of the positive end terminal or the negative end terminal of the cells in the cell array 101 . In other words, the cell array 101 is sandwiched between two layers of the plurality of heat and current collector panels 102. Each layer of heat and current collector panels 102 comprising plurality of heat and current collector panels 102 arranged side by side to each other. Each of the heat and current collector panel 102 is adapted to transfers the heat as well as current to the heat spreader 103 to prevent an individual cell from overheating and spread the heat across the array.

[0032] A plurality of heat spreaders 103 are provided at the junction of two nearby heat and current collector panels 102 arranged in a side-by-side configuration to collect heat received from the end terminals therefrom. This arrangement maintains a uniform temperature across the length and width of the cell array 101 . In a thermal run-away scenario, this arrangement ensures the spreading of the sudden burst of heat inside the affected cell, which otherwise adversely affects all the cells.

[0033] In a preferred embodiment of the present invention, the heat spreader 103 is made from a very high in-plane thermal conductive material.

[0034] Battery pack A further comprises a first thermal pad 104a mounted on the plurality of heat spreader 103 at the top side of the battery pack. Battery pack A further comprises a second thermal pad 104b mounted on the plurality of heat spreader 103 at the bottom side of the battery pack. In a preferred embodiment of the present invention, the first thermal pad 104a and the second thermal pad 104b are structurally and materially the same. In a more preferred embodiment of the invention, the first thermal pad 104a and the second thermal pad 104b are silicon thermal pads.

[0035] The battery pack A further comprises a cooling plate 105 provided on the thermal pad 104a. The cooling plate 105 has a passage for circulating a coolant to withdraw heat from the first thermal pad 104a. The cooling plate has an inlet 105a and an outlet 105b. The cooling plate 105 comprises a spiral passage throughout its length for circulating the coolant received from the inlet 105a towards outlet 105b.

[0036] The battery pack A further comprises an L-shaped heat spreader 106 arranged on the second thermal pad 104b. In simple words, the cell array 101 comprises a cooling plate 105 at one side and comprises an L-shaped heat spreader 106 at the opposite end of the cell array 101. The L-shaped heat spreader 106 is configured to arrange in a way that longer part of the “L” is used to provide mechanical and structural strength to the battery pack A, while shorter end is used to transfer the heat collected from the second thermal pad 104b to the cooling plate 105 provided at the opposite side of the battery pack A. This arrangement ensures a uniform and faster heat extraction from both end terminals of each and every cell of the cell array 101 in a battery pack A.

[0037] FIG. 2 shows a more detailed and exploded perspective view of battery pack A of the system 100 according to an embodiment of the present invention. The cell array 101 is sandwiched between the heat and current collector panel 102, the heat spreader 103, the first thermal pad 104a, the second thermal pad 104b, cooling plate 105, and L-Shaped heat spreader 106 in a predefined arrangement as aforementioned, and as such, duplication of description is therefore avoided.

[0038] FIG. 3 shows a perspective isometric view of the heat and current collector panel 102 of the battery pack of FIG. 2 according to a preferred embodiment of the present invention.

[0039] The heat and current collector panel 102 is formed by combining the first plate 102a and the second plate 102b. The first plate is 102a comprises multiple circular openings 10 formed therein. Each of the circular openings 10 has a first width W1 . The second plate 102b comprises a plurality of trapezoidal projections 20 formed thereon. The position of trapezoidal projections 20 on the second plate 102b is correspondent to the position of the circular openings provided on the first plate 102a.

[0040] The trapezoidal projections 20 has a top flat face 20a having a second width W2, and a side wall 20b extending downwardly from the top toward a base 20c of the projection 20. The base 20c of the projection has a third width W3. In a preferred embodiment of the invention, the second width W2 is lesser than the third width W3 and the third width W3 is equal to the first width W1 . In other words, the width W3 of the base of the projection 20 and the width W1 of the opening 10 is the same; the width W2 of the top flat face of the projection 20 is smaller than the base W3 of the projection 20. The top flat face 20a is configured to form an electrical and thermal contact with the terminal of each cell in the cell array 101 when arranged on the cell array 101 for transfer of heat and current generated therein.

[0041 ] In a preferred embodiment of the invention, the width of the top face 20a of the projection 20 is similar to the width of the end terminal of the cell in the cell array 101 of the battery pack A. In an alternative embodiment of the invention, the width of the top face 20a of the projection 20 is slightly greater than the width of the end terminal of the cell in the cell array 101 of the battery pack A.

[0042] In a preferred embodiment of the invention, the heat and current collector panel 102 is formed by mounting the second plate 102b on the first plate in a manner that base 20c of the each of projection 20 is aligned with its corresponding opening 10. In a preferred embodiment of the invention, the first plate 102a and the second plate 102b of the heat and current collector panel 102 are made of different materials. The first plate 102a is made of aluminium, while the second plate 102b is made of nickel. Use of aluminium imparts mechanical strength to the heat and current collector panel 102.

[0043] The second plate further comprises a cut-out or opening 20c formed in the side face of each of the projection 20 for venting the gases. In a preferred embodiment, the cut-out or opening 20c has a shape, but is not limited thereto, rectangular, oval, square shape. It may be any shape as long as serving the purpose for venting gases. This reduces the chances of an explosion happening in individual cells and/or overall battery pack A.

[0044] In a preferred embodiment of the invention, the cell array further comprises a holder 122 to hold each individual cell of the cell array 101 in a predefined configuration. The predefined configuration of cells in the cell array 101 is correspondent with the position of the trapezoidal projection 20 of the plurality of the heat and current collector panels 102.

[0045] Referring again to FIG. 1 , system 100 further comprises a cooling circuit B which extracts heat from the cooling plate 105 of the battery pack A. The cooling circuit B includes coolant pump 107 configured to circulate a coolant inside the cooling plate 105. The cooling circuit further comprises a plurality of heat ejectors which includes radiator (108) and/or radiator Fan (109). In a preferred embodiment of the invention, the flow of the coolant in the cooling plate 105 can be controlled by controlling coolant pump 107.

[0046] In a preferred embodiment of the invention, the coolant is at least one selected from the group comprising water, ethylene glycol, oil, and air. In a more preferred embodiment of the invention, the coolant is ethylene glycol. In another erred embodiment of the invention, the coolant is a mixture of water and glycol.

[0047] System 100 further comprises a battery pack thermal management system C which dynamically control the cooling of the cell array based on the one or more of battery pack A conditions, cooling circuit B conditions, ambient conditions and driving mode or conditions of the electric vehicle.

[0048] The cooling of the battery pack is affected by the current status of the battery pack, ambiance, the efficiency of the cooling circuit and driving condition of the vehicle. To avoid the formation of thermal propagation and thermal hotspot inside the battery pack, it is essential to match the temperature of the battery pack with the temperature of ambience. For example, if the vehicle is driven at high speed in a cold atmosphere, the cooling of the battery pack requires a high flow of cold coolant compared to an alternative driving condition, i.e. driving at low speed in a warm atmosphere. In a second scenario, the battery pack thermal management system C of system 100 need to control the cooling parameters to maintain temperature of the battery pack to match with that of the ambience. The battery pack thermal management system C preferably regulates the performance of the cooling circuit in real time as per the driving conditions of the vehicle and ambient conditions to maximise the efficiency of the cooling system.

[0049] In a preferred embodiment of the invention, the battery pack thermal management system C comprises a plurality of temperature sensors configured to sense the temperature of at least one of coolant, atmosphere and the battery pack, a plurality of flow rate sensors configured to sense flow rate of the coolant pump 107 and radiator fan 109, and a plurality of sensor for sensing vehicle driving conditions and battery pack SOC/SOH.

[0050] To achieve an optimum operating condition of the battery pack A, the battery pack thermal management system C takes input from the sensors to manage cooling circuit B by controlling the flow rate of the coolant pump 107 in accordance with the desired temperature to be maintained. This is particularly, important to avoid thermal hotspot and propagation inside the battery pack and to maximise the efficiency of the cooling circuit and battery pack.

[0051 ] In an alternative embodiment of the invention, the battery pack thermal management system C manages cooling circuit B by controlling the flow rate of the radiator fan 109 along with coolant pump 107 to obtain cooling of the battery pack at a desired temperature.

[0052] In another embodiment of the invention, the battery pack thermal management system C may configure to monitor the functioning of the Battery Pack A to prevent thermal failure in the vehicle. In case of detection of thermal failure, the battery pack thermal management system C will cut off the power output from the battery pack to prevent any further heat generation inside the system due to current flow. The battery pack thermal management system C is further capable of reducing draining of Low voltage battery/power drawn from Low voltage system thus increasing the overall range of the vehicle.

[0053] System 100 provides a compact cooling system for battery pack A as it is adapted to extract heat from both end terminals of the cells, eliminating the need to surround each cell with a cooling means. This reduces the weight and size of the power pack of the vehicle 100. This also increased the power Density (Wh/Kg) of the Powerpack.

[0054] The novel architecture of the system 100 makes sure that the Battery pack A is operating in recommended temperature range during charging/ discharging thus increasing the life of the battery pack. This also increases the overall range of the vehicle.

[0055] FIG. 4a shows a cross-sectional view of the power pack with an integrated active thermal management system according to a preferred embodiment of the present invention. System 100 comprises two battery packs A1 , A2 arranged in parallel within an electric vehicle. The battery packs A1 , A2 are combined and mounted by side-by-side arrangement of the L-shaped heat spreader 106 of both the battery packs A1 , A2 such that cooling plates 105 of both the battery pack A1 , A2 remains at the outer side of the combined battery pack. The same cooling circuit B and the battery pack thermal management system C is used to cool both the battery packs A1 , A2 in a manner as explained aforementioned, and as such, duplicate description is avoided. In an alternative embodiment of the invention, the system 100 may comprises more than two battery pack. A depending upon the power requirement. Here, cooling of each of the battery pack A1 , A2 is controlled by the single battery pack thermal management system C and cooling circuit B as discussed above.

[0056] FIG. 4b and 4c shows an enlarged view of the portion indicated by circle 100a and 100b respectively. FIG. 4b shows a cell array 101 a of battery pack A1 , which at its terminal end in contact with the projection 20 of the heat and current collector panel 102, which in turn in contact with the plurality of heat spreader 103, a thermal pad 104, a cooling plate 105, and an L-Shaped heat spreader 106 in manner as discussed above. FIG. 4c shows implementation of power pack 100 containing two number of battery packs, that is battery pack A1 containing cell array 101 a and battery pack A2 containing cell array 101 b according to a preferred embodiment of the invention.

[0057] In a preferred embodiment of the invention, the system 100 is capable of implemented within an electric vehicle, more particularly the electric vehicle having at least two wheels, more preferably, but is not limited thereto, within vehicles having three or four wheels. In an alternative embodiment of the invention, the system 100 can be efficiently incorporated in any application using a high-voltage battery as a source of power in any other industries without departing from spirit and scope of the invention.

[0058] In the description of the present invention, it should be noted that the terms "side", “top”, “bottom”, and the like indicate the directions or positional relationships based on the directions or positional relationships shown in the drawings, or the directions or positional relationships that the products of the present invention are conventionally placed when used, and are only for the convenience of describing the present invention and simplifying the description, but do not indicate or imply that the device or element to be referred to must have a specific direction, be constructed and operated in a specific direction, and thus, should not be construed as limiting the present invention.

[0059] Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art. Any minor modification, equivalent replacement and improvement made to the above embodiments according to the technical essence of present invention should all be included within the scope of protection of the technical solution of the present invention.

ABSTRACT

A power pack with an integrated active thermal management system for an electric vehicle is provided. The power pack comprises at least one battery pack A, a cooling circuit B, and a battery pack thermal management system C. Each of the battery packs comprises a cell array 101 , a plurality of heat and current collector panels 102, a plurality of heat spreader 103, a thermal pad 104, a cooling plate 105, and an L- Shaped heat spreader 106. The plurality of heat and current collector panels 102 arranged in a side by side arrangement on top as well as bottom side of the battery pack for faster and efficient heat extraction from each cell of the cell array.