Description:Preamble to the Description

[0001] The following specification particularly describes the invention and the manner in which it is to be performed:
DESCRIPTION OF THE INVENTION
Technical field of the invention
[0002] The present invention relates to a system of thermal management of battery packs for improved performance and safety. The invention particularly relates to a system for thermal management and safety of the battery pack against thermal run-away propagation and internal short circuit by utilizing phase change material and thermal resistant sheets in electric vehicles and all other battery applications.
Background of the invention
[0003] With the rapid development of new energy vehicles, electric-powered vehicles have gradually gained a large market share. The battery is the primary energy storage structure in an electric vehicle, and its electric quantity, safety performance, and other characteristics have a significant impact on the vehicle's performance. The battery may be provided as a battery pack constructed by integrating a number of battery cells. To ensure stable and reliable operation, battery packs for electric vehicles and all other battery applications require a thermal management system to keep the temperature inside the battery pack within a reasonable range. The thermal management of the battery pack is directly related to the battery's service life and operating efficiency.
[0004] The battery pack applied to an electric vehicle and other battery applications have a structure in which a plurality of battery modules including a plurality of battery cells are connected to obtain high power. Battery pack is used as the primary power source for the operation of the pure electric vehicle and the hybrid vehicle, and the conditions that must be met by the normal operation of the battery pack are stringent, with the operating temperature of the battery pack required to be within a certain temperature range in order to operate in an equilibrium state. However, heat is generated from the battery cells when the battery pack is charged and discharged, and the performance of the battery cells continues to suffer when the generated heat is ignored, potentially shortening the battery cells' life. Furthermore, due to the high consumption rate of the battery at low temperatures, such as during the winter, the battery pack may be discharged quickly. Heat generated by the battery cells needs to be dissipated efficiently to achieve lower operating temperatures as required for better lifecycle and safety of the battery.
[0005] As a result, the battery must be thermally managed so that it operates at the appropriate temperature interval and the temperature distribution between the single battery and the module/pack is uniform. Therefore, battery thermal management technology becomes a critical technology for limiting the development of the electric vehicle as well as other battery applications.
[0006] For instance, Chinese Patent Application No. CN209843900U titled “Battery pack thermal management system” discloses a battery pack heat management system, which comprises a mounting rack for fixing a battery; the mounting frame comprises a bottom plate provided with a cooling pipe, two side plates vertically fixed on two opposite sides of the bottom plate, and two groups of baffle plates which are inserted into the two side plates and used for enclosing the two side plates into a battery mounting part; the inner wall of the side plate is provided with a heating part for heating the battery arranged in the battery installation part. The bottom plate provided with the cooling pipe, the side plate provided with the heating part and the baffle plate in the mounting frame can be mutually combined and are surrounded into a battery mounting part so as to facilitate the disassembly and assembly of the battery; the labor division is clear, and the heat dissipation function and the heating function of the mounting rack are achieved through a small mounting space. However, “CN209843900U” only a mounting frame for fixing a battery comprising a bottom plate provided with a cooling pipe and does not disclose details pertaining to metallic bus bars with leaf spring type arrangement for connecting the cells both in series and parallel.
[0007] For instance, PCT Application No. WO2016200144A1 titled “Battery pack thermal management system for electric vehicle” discloses a battery pack thermal management system for an electric vehicle. The battery pack thermal management system includes a refrigerant cycle circuit in which refrigerant is circulated through a compressor, a condenser, an expander, and an evaporator, a coolant circulation circuit in which water is circulated through a battery pack by a circulation pump, and a heat exchange module disposed to share portions of the refrigerant cycle circuit and the coolant circulation circuit, so as to exchange heat between the water and the refrigerant branched from the refrigerant cycle circuit to cool the battery pack using the water or so as to electrically heat the water and then heat the battery pack using the heated water. Consequently, it is possible to reduce costs and weight and improve the degree of design of peripheral components. However, “WO2016200144A1” only discloses a heat exchange module disposed to share portions of the refrigerant cycle circuit and the coolant circulation circuit, so as to exchange heat between the water and the refrigerant branched from the refrigerant cycle circuit to cool the battery pack and does not disclose details pertaining to thermal paste that is used in the cavity between the cells and the fireproof material tube to effectively transfer heat. .
[0008] For instance, Chinese Patent Application No. CN113581013A titled “Thermal management control system and control method for battery pack of hybrid electric vehicle” discloses a hybrid electric vehicle battery pack heat management control system and a control method, wherein the control system comprises an engine cooling and air conditioning refrigerant and a battery pack heat management control module, and the engine cooling control module comprises an engine waterway assembly, an engine water temperature sensor, a one-way valve and a heat exchanger which are sequentially connected in series; the air-conditioning refrigerant control module comprises an air-conditioning system assembly, an electronic expansion valve and a refrigerant plate exchanger which are sequentially connected in series; the battery pack heat management control module comprises a battery pack internal water path assembly, an electronic water pump, a two-position three-way electromagnetic valve, a refrigerant plate exchanger and a heat exchanger which are sequentially connected in series. The control system of the invention designs four heat management control modes of pre-cooling at medium and low temperature, high-efficiency heat exchange cooling at high temperature, heating at extremely low temperature and energy balance of the battery core, so that the battery pack can be freely switched between an energy-saving mode and a high-efficiency mode along with the change of external environment, the load of the whole vehicle and the temperature of the battery core, and the ineffective energy consumption of the battery pack is reduced. . However, “CN113581013A” only discloses an input end of the battery pack thermal management controller electrically connected with the ambient temperature sensor and does not disclose details pertaining to plurality of fins with different orientation protruding out on the outside surfaces of the battery module. battery pack including the same, and a vehicle capable of improving the cooling efficiency of the edge portion and the sealing portion of the battery cell.
[0009] Hence, there exists a need for a system that regulates the flow of thermal energy and hot gas generated by a battery cell of a battery pack of the vehicle.
Summary of the invention:
[0010] The present invention overcomes the drawbacks of the prior art by disclosing a system for thermal management of battery packs for improved performance and safety. The system comprises a battery pack comprising a plurality of battery cells and cavities encased within a battery case, wherein every alternate battery cell is separated from the others by a thermal conductive fireproof material tube to conduct and transfer the heat in case of thermal runaway event and in normal battery operation. Further, the system comprises at least one thermal resistant material sheet disposed in thermal contact with the plurality of battery cells and phase change material. Furthermore, the system comprises a plurality of fins with different orientation protruding out on the outside surface of the battery pack to expel the heat generated inside the battery pack to the surrounding.
[0011] The present invention discloses a system for thermal management of battery packs for improved lifecycle and thermal efficiency with better safety against thermal run-away propagation . The system helps in removing the heat from both axial and radial sides of the battery cells by introducing phase change material on radial side and by conduction through bus bars and heat sinks from axial side. The system provides barrier for thermal runaway propagation by introducing thermal insulation sheet between every cell. Further, the system helps in minimizing the high temperature hotspots between two battery modules/packs by providing conductive path for the contaminated heat. Further, the system helps in reducing the maintenance time by using non-permanent electrical connections supported by leaf springs arrangement with fuse structure to separate any cell if gets short circuited. Further, the system incorporates plurality of fins with unique orientation for improving the convective heat transfer and for creating turbulence. Further, the system helps in achieving modularity without compromising the thermal management and structural integrity of the battery pack. Further, the system provides accessibility for battery swapping. Furthermore, the system provides better ingress protection from moisture, water and dust, which may damage the battery cells.
Brief Description of drawings
[0012] Figure 1 illustrates a schematic diagram of a battery pack thermal management system, in accordance with one embodiment of the present invention.
[0013] Figure 2 illustrates an exploded perspective view of a thermal resistant material sheet, in accordance with one embodiment of the present invention.
[0014] Figure 3 illustrates a schematic structural diagram of one battery pack in a battery module, in accordance with one embodiment of the present invention.
[0015] Figure 4 illustrates an exploded view of the metallic bus bars connecting battery cells, according to an embodiment of the present invention.
[0016] Figure 5 illustrates a structural view of fins according to an embodiment of the present invention.
Detailed description of the invention
[0017] In order to more clearly and concisely describe and point out the subject matter of the claimed invention, the following definitions are provided for specific terms, which are used in the following written description.
[0018] The present invention provides a system for thermal management of battery packs for improved performance with better safety against thermal run-away propagation. By introducing phase change material on the radial side and conduction through bus bars and heat sinks on the axial side, the present invention assists in removing heat from both the axial and radial sides of the battery cells. The present invention creates a barrier against thermal runaway propagation. Furthermore, by providing a conductive path for the contaminated heat, the present invention aids in the reduction of high temperature hotspots between two battery modules/packs and thermal balance in single module as well. Further, the present invention reduces maintenance time by utilizing non-permanent electrical connections supported by a leaf spring arrangement. Further, the present invention incorporates a plurality of fins with distinct orientations for improving convective heat transfer and creating turbulence. Further, the current invention aids in achieving modularity without adversely affecting the thermal management and structural integrity of the battery pack. Further, the current invention allows for battery swapping. Furthermore, the present invention provides improved ingress protection from moisture, water, and dust, which can damage battery cells.
[0019] Figure 1 illustrates a schematic diagram of a battery pack thermal management system, wherein the system (100) comprises a battery pack (101) comprising a plurality of battery cells (102) and cavities (103) encased within a battery case (104), wherein every alternate battery cell (102) is separated from the others by a thermal conductive fireproof material tube (105) to spread heat in case of thermal runaway event. Further, the system (100) comprises at least one thermal resistant material sheet (106) disposed in thermal contact with the plurality of battery cells (102) and phase change material (109). Furthermore, the system (100) comprises a plurality of fins (107) with different orientation protruding out on the outside surface of the battery pack (101) to expel the heat generated inside the battery pack (101) to the surrounding.
[0020] In an embodiment, the battery case/casing (104) is filled with a phase changing material (109) for absorbing the heat generated by the battery pack (101). The battery cells (102) are structurally bounded with the aid of one or more holders (108) which may be made of materials such as plastic or other material with high insulation properties known in the present state of the art. The battery cells (102) are electrically connected to each other by one or more metallic bus bars (110) with a leaf spring type arrangement (111) for saving the time consumed in assembling the battery cells (102) within the battery pack (101). In an embodiment, the phase changing material (109) has the property to absorb heat from the battery cells (102) without rising self-temperatures, because of its high latent heat capacity.
[0021] In an embodiment, during a thermal runaway event, a huge amount of thermal energy is rapidly released, increasing the temperature of the entire battery cell (102). The temperature of adjacent cells (102) within the battery pack (101) will rise as a result of the increased temperature of the cell (102) undergoing thermal runaway. If the temperature of these adjacent cells (102) is permitted to increase unabated, they may also enter a state of thermal runaway, resulting in a cascading effect in which the initiation of thermal runaway within a single cell (102) propagates throughout the entire battery pack (101). As a result, power from the battery pack (101) is interrupted, and the system (100) employing the battery pack (101) is more likely to sustain exhaustive collateral damage due to the magnitude of thermal runaway.
[0022] In an embodiment, the heat generated by the battery cells (102) must be dissipated efficiently in order to achieve lower operating temperatures required for improved lifecycle and safety. The heat generated in the radial direction is absorbed by the phase changing material (109) into which the batteries are dipped/immersed. More particularly, the battery packs (101) are dipped/immersed in the phase changing material (109), thereby absorbing the heat generated by the battery cells (102) assembled in the battery packs (101). Because of the high latent heat capacity of the phase changing material (109), the phase changing material (109) absorbs the heat without increasing its own temperature. On the contrary, axial heat or the heat generated in the axial side/ surface of the battery cells (102) is dissipated by the conduction process from the battery cells (102) to the metallic bus bars (110), and further, from the metallic bus bars (110) to the battery casing (104) and subsequently by the convection process from the fins (107) to atmospheric air.
[0023] In an embodiment, due to the battery casing (104) design, each battery cell (102) dissipates heat at the same rate through the tab. As a result, each battery cell (102) has access to the same quantity of the phase changing material (109), resulting in homogeneous heat dissipation from the battery cells (102), thereby lowering down the temperature gradient across the battery pack (101).
[0024] In an embodiment, at least one thermal resistant material sheet (106) is inserted between each battery cell (102) and phase change material (109), thereby preventing the heat from flowing from one battery cell (102) to another. The cavities (103) between the battery cells (102) and the fireproof material tube (104) are filled with a thermal paste to effectively transfer heat by increasing the overall heat transfer coefficient.
[0025] Figure 2 illustrates an exploded perspective view of a thermal resistant material sheet, in accordance with one embodiment of the present invention. In an embodiment, at least one thermal resistant material sheet (106) is disposed in thermal contact with the plurality of battery cells (102) and phase change material (109). More particularly, at least one thermal resistant material sheet (106) is inserted between each battery cell (102) and phase change material (109), to prevent the heat from flowing from one battery cell (102) to another.
[0026] In an embodiment, the thermal resistant material sheets (106) placed between plurality of battery cells (102) avoids thermal propagation. The thermal resistant material sheets (106) does not allow heat to pass through it, resulting in damage to only one cell that has gone into runaway due to any means of failure.
[0027] In an embodiment, the battery cells (102) preferably Lithium-ion battery cells (102) of cylindrical shape are electrically connected to each other by the one or more metallic bus bars (110) and are structurally bounded with the aid of one or more holders (108).
[0028] FIGURE 3 illustrates a schematic structural diagram of one battery pack in a battery module. In an embodiment, the battery pack (101) used in an electric vehicle has a structure that connects a number of battery modules, each of which contains the plurality of battery cells (102), to obtain high power. Furthermore, each battery cell (102) is an electrode assembly that can be charged and discharged repeatedly through an electrochemical reaction involving components such as a positive electrode and a negative electrode current collector, an electrolyte, and the like.
[0029] FIGURE 4 illustrates an exploded view of the metallic bus bars connecting battery cells, according to an embodiment of the present invention. The metallic bus bars (110) with the leaf spring type arrangement (111) ensures electrical continuity between the battery cells (102), saves assembly time and also aids in thermal management by conducting heat from the battery cell (102) tabs to the battery casing (104) through a thermal tape. In an embodiment, the thermal tape may be applied to the flat side of the metallic bus bars (110) to conduct heat from the metallic bus bars (110) to the battery casing (104). The thermal tape may preferably be both electrically insulating and thermally conductive.
[0030] In an embodiment, the battery casing (104) for assembling the battery pack (101) is manufactured from casting process with one solo part and one electronics box tightened by nut and bolts to provide ingress protection to the battery pack (101). More particularly, the battery casing (104) and the electronics box is connected to each other using gasket/end cover and studs/nuts for providing ingress protection (from moisture, water and dust) to the battery pack (101). which may otherwise damage the battery cells (102). A specific amount of torque may be applied on nuts and bolts to achieve tightness required to provide ingress protection to the battery pack (101).
[0031] FIGURE 5, illustrates a structural view of fins according to an embodiment of the present invention. The orientation of the fins (107) is designed in accordance with the airflow to improve the contact of air and fins (107), and thereby improving the convection rate. The fins (107) preferably horizontal side are provided to increase the amount of heat transfer area in contact with the air flow, resulting in better heat transfer results.
[0032] In an embodiment, the system (100) may include a battery swapping feature because all of the components required for thermal management are housed within the battery pack (101). The entire battery pack (101) may be simply removed from the vehicle to be charged elsewhere.
[0033] In an embodiment, the system (100) includes a group of fans that can enhance air flow velocity, causing more turbulence and speeding up the rate of heat transfer. The heat transfer coefficient in low velocity air flow may be further improved as a result.
[0034] In an embodiment, the system (100) may remove heat from the axial surface/side and cylindrical surface/side of cells by incorporating the phase changing material (109) on the radial surface of the battery cells (102) and further by conduction process through the metallic bus bars (110) and battery casing (104) on the axial surface. Further, the system (100) incorporates plurality of fins (107), more particularly horizontal fins providing more area for air to pass over it, thereby removing the heat by convection process to the surrounding environment, and further, lowering the temperatures inside the battery pack (101) by efficiently dissipating heat.
[0035] The present invention provides a system for thermal management of battery packs (101) for improved performance and safety. The system (100) assists in removing heat from both the axial and radial sides of the battery cells by introducing phase change material (109) on the radial side and conduction through metallic bus bars (110) and heat sinks on the axial side. The system (100) provides barrier for thermal runaway propagation by introducing resistant material sheet (106) between every cell. Further, the system (100) aids in the reduction of high temperature hotspots between two battery modules/packs (101) by providing a conductive path for the contaminated heat. Further, the system (100) reduces maintenance time by utilizing non-permanent electrical connections supported by the leaf spring arrangement (111). Further, the system (100) incorporates a plurality of fins (107) with distinct orientations for improving convective heat transfer and creating turbulence. Further, the system (100) aids in achieving modularity without jeopardizing the thermal management and structural integrity of the battery pack (101). Further, the current invention allows for battery swapping. Furthermore, the system (100) provides improved ingress protection from moisture, water, and dust, which can damage the battery cells (102).
Reference numbers:
Components Reference Numbers
System 100
Battery packs 101
Battery cells 102
Cavities 103
Battery Case 104
Thermal conductive fireproof material tube 105
Thermal resistant material sheet 106
Plurality of fins 107
Holders 108
Phase changing material 109
Metallic bus bars 110
Leaf spring type arrangement 111
, Claims:Claims
We claim:
1. A system for thermal management of battery packs for improved performance and safety, the system (100) comprising:
a. a battery pack (101) comprising a plurality of battery cells (102) and cavities (103) encased within a battery case (104), wherein every alternate battery cell (102) is separated from the others by a thermal conductive fireproof material tube (105) to spread heat in case of thermal runaway event and normal battery operation;
b. at least one thermal resistant material sheet (106) disposed in thermal contact with the plurality of battery cells (102) and a phase change material (109); and
c. a plurality of fins (107) with different orientation protruding out on the outside surface of the battery pack (101) to expel the heat generated inside the battery pack (101) to the surrounding.

2. The system (100) as claimed in claim 1 wherein the battery cells (102) are structurally bounded with the aid of one or more holders (108).

3. The system (100) as claimed in claim 1 wherein the battery casing (104) is filled with a phase changing material (109) for absorbing the heat generated by the battery pack (101).

4. The system (100) as claimed in claim 1, wherein the battery cells (102) are electrically connected to each other by one or more metallic bus bars (110) with a leaf spring type arrangement (111) for saving the time consumed in assembling the battery cells (102).

5. The system (100) as claimed in claim 1, wherein at least one thermal resistant material sheet (106) is inserted between each battery cell (102), thereby preventing the heat from flowing from one battery cell (102) to another.

6. The system (100) as claimed in claim 1, wherein the cavities (103) between the battery cells (102) and the fireproof material tube (104) are filled with a thermal paste to effectively transfer heat by increasing the overall heat transfer coefficient.

7. The system (100) as claimed in claim 1, wherein the plurality of fins (107) expel the heat generated inside the battery pack (101) to the surrounding by convective heat transfer.

8. The system (100) as claimed in claim 1, wherein the battery casing (104) for assembling the battery pack (101) is manufactured from casting process with one solo part and one electronics box tightened by nut bolts to provide ingress protection to the battery pack (101).