Description:TECHNICAL FIELD
[0001] The present disclosure relates, in general, to the field of the design of battery modules. More particularly, embodiments of the present disclosure relate to a battery module design for stopping thermal propagation. The present disclosure focuses on enhancing safety and efficiency by addressing key issues related to thermal propagation management, venting, and contaminant prevention.
BACKGROUND
[0002] The background information herein below relates to the present disclosure but is not necessarily prior art.
[0003] In recent years, the automotive industry has undergone a transformative shift towards electrification, driven by the need for cleaner and more sustainable transportation solutions. High-voltage electric power trains, commonly found in electric vehicles (EVs) and hybrid electric vehicles (HEVs), are at the forefront of this paradigm shift. These power trains rely on advanced battery technologies to store and deliver the high amounts of energy required for efficient and powerful electric propulsion.
[0004] Battery modules play a crucial role in the functionality and performance of these advanced battery technologies. These modules, composed of individual cells, serve as the energy storage units responsible for storing electrical energy during charging and delivering it to power the vehicle's electric motor during operation. The design of battery modules significantly influences the range, charging speed, and overall efficiency of electric vehicles.
[0005] Even though most commercial EVs & HEVs mainly use nickel-metal hydride (NiMH) batteries owing to their longer life cycles, it has been discovered that Lithium-ion batteries also have great potential and can be widely used in future EVs & HEVs. In fact, because of its advantages in volume, weight, and life, it is expected that lithium-ion batteries would become the mainstream in the future.
[0006] The lithium-ion cell vents gases when subjected to high temperature, mechanical force, internal or external short circuits, etc. The cell venting is an exothermic reaction that raises the temperature of the cell & the venting gas. The high-temperature vent gas can encounter the neighboring cells in a battery module & can trigger a chain reaction of exothermic reaction leading to the phenomenon called, “thermal propagation”.
[0007] Most of the prior art shows that in the event of thermal propagation, the vent gases from the cell can escape the module from any direction. The end plates on both the sides are also designed to collect vent gases from any cell which exits the module via a common hole provided in the endplates or even the module housing. Therefore, recirculation of venting gases between cells occurs very often promoting cross-contamination and triggering venting in neighbouring cells.
[0008] Therefore, there is a need to develop a battery module design for stopping thermal propagation that can alleviate the aforementioned drawbacks.
OBJECTS
[0009] Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows.
[0010] It is an object of the present disclosure to ameliorate one or more problems of the prior art or to at least provide a useful alternative.
[0011] The main object of the present disclosure is to provide a battery module for stopping thermal propagation.
[0012] Another object of the present disclosure is to provide a battery module for high-voltage battery packs that provides isolation of battery cells during venting events.
[0013] Yet another object of the present disclosure is to provide individual venting gas passages for each cell.
[0014] Still another object of the present disclosure is to provide a battery module for bus bar frame & end plate assembly design which can direct cell venting gas to one side of the module.
[0015] Other objects and advantages 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
[0016] This summary is provided to introduce concepts related to a battery module design for stopping thermal propagation. The concepts are further described hereinbelow in the following detailed description. This summary is not intended to identify essential features of the claimed subject matter nor is it intended for use in determining or limiting the scope of the claimed subject matter.
[0017] The present disclosure envisages a battery module design for stopping thermal propagation. The battery module comprises a cell stack assembly, a bus bar frame assembly, a module housing, and a pair of end plate assemblies.
[0018] The cell stack assembly (cell module) includes a plurality of cells with thermal insulation pads therebetween to define a plurality of isolated venting pockets for each of the plurality of cells.
[0019] The bus bar frame assembly covers an upper surface along with front and rear sides of the cell stack assembly such that from the front and rear sides of the cell stack assembly, cell tabs of the cell stack assembly protrude from the bus bar frame and those cell tabs are further bent over the bus bars & welded to it.
[0020] The module housing has a top surface, a bottom surface, and side surfaces for accommodating a coupled body of the cell stack assembly and the bus bar frame assembly.
[0021] The pair of end plate assemblies is coupled to the front and rear sides of the cell stack assembly in such a manner that the pair of end plate assemblies includes a first end plate assembly through which cell venting gases escape from the cell stack assembly and a second end plate assembly configured to block the cell venting gases and diverts the cell venting gases towards the first end plate assembly.
[0022] In an aspect, the first end plate assembly consists of an end plate housing having multiple venting ports through which cell venting gases escape from the cell stack assembly, an isolation cover coupled to the end plate housing to guide the cell venting gases toward the multiple venting ports, an isolation foil provided between the end plate housing that prevents the entry of any contaminants into the battery module.
[0023] In an aspect, the isolation foil is made up of Polyethylene terephthalate (PET).
[0024] In an aspect, the second end plate assembly consists of an end plate housing having an isolation cover coupled to the end plate housing, a resin pouring hole formed on the top side of an intermediate assembly of the end plate housing and the isolation cover so as to pour epoxy resin in the intermediate assembly for blocking escape of the cell venting gases via second end plate assembly & redirecting the cell venting towards the first end plate assembly and a resin stopper assembled to the intermediate assembly to seal the second end plate assembly with the cell stack assembly.
[0025] In an aspect, the end plate housing is a metal housing.
[0026] In an aspect, the resin stopper is a flexible polyurethane / silicone foam.
[0027] In an aspect, the first end plate assembly is coupled to a low voltage side of the bus bar frame assembly, and the second end plate assembly is coupled to a high voltage side of the bus bar frame assembly.
[0028] In an aspect, the plurality of cells are connected in a combination of series and parallel connections through multiple bus bars of the bus bar frame assembly.
[0029] In an aspect, the plurality of thermal insulation pads is arranged between two adjacent cells to thermally isolate each one of the plurality of cells from other cells.
[0030] In an aspect, the venting ports include angular venting passages at extreme ends of the cell stack assembly.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
[0031] FIG. 1 illustrates two perspective views, a front view, and two top views of either side of the battery module design for stopping thermal propagation, in accordance with an embodiment of the present disclosure;
[0032] FIG. 2 illustrates a perspective view of a cell stack assembly, in accordance with an embodiment of the present disclosure;
[0033] FIG. 3A illustrates a cell stack assembly with multitude of cells enclosed within a metallic foil, preferably made of aluminium, in accordance with an embodiment of the present disclosure;
[0034] FIG. 3B illustrates the cell stack assembly with potential region of cell venting through pockets provided therein, in accordance with an embodiment of the present disclosure;
[0035] FIG. 4 illustrates a top view of the cell stack assembly with thermal insulation pads 104, in accordance with an embodiment of the present disclosure;
[0036] FIG. 5 illustrates different components of the second end plate assembly in an exploded view, in accordance with an embodiment of the present disclosure;
[0037] FIG. 6 illustrates the resin stopper interface, in accordance with an embodiment of the present disclosure;
[0038] FIG. 7 illustrates the high voltage side of the bus bar frame assembly alongwith provision for epoxy resin pouring highlighted in dark, in accordance with an embodiment of the present disclosure;
[0039] FIG. 8 illustrates the cross-sectional view of the high voltage side of the bus bar frame assembly to show the cavity meant for epoxy resin, in accordance with an embodiment of the present disclosure;
[0040] FIG. 9 illustrates a side and a magnified view of the cross-section of the high voltage side of the bus bar frame assembly to further depict how epoxy resin blocks the cell venting on one side of the module, in accordance with an embodiment of the present disclosure;
[0041] FIG. 10 illustrates a side and a magnified view of the cross-section of the low voltage side of the bus bar frame assembly alongwith a top view of pockets for cell gas venting and extended thermal insulation pads for cell isolation provided therein, in accordance with an embodiment of the present disclosure;
[0042] FIG. 11A illustrates an enlarged cross-section view of the high voltage side of the bus bar frame assembly, in accordance with an embodiment of the present disclosure; and
[0043] FIG. 11B illustrates an extended window on the low voltage (LV) side of the bus bar frame assembly for cell gas venting purpose, in accordance with an embodiment of the present disclosure.
LIST OF REFERENCE NUMERALS USED IN THE DESCRIPTION AND DRAWING:
100 Battery module
102 Cell stack assembly
102A Cells
104 Thermal pads
105 Extended Thermal pads
106 Bus bar frame assembly
108 Module housing
108A Top surface of module housing
108B Bottom surface of module housing
108C Side surfaces of module housing
110 First End Plate Assembly
112 Second End Plate Assembly
112A End plate housing of Second End Plate Assembly
112B Isolation cover (Second End Plate Assembly)
112C Resin pouring hole
112D Resin Stopper
113 Epoxy Resin
114 Venting pockets
114A Extended Window

DETAILED DESCRIPTION
[0044] Embodiments, of the present disclosure, will now be described with reference to the accompanying drawing.
[0045] Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth, relating to specific components and methods to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known apparatus structures, and well-known techniques are not described in detail.
[0046] The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms “a”, “an”, and “the” may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms, “comprises”, “comprising”, “including” and “having” are open-ended transitional phrases and therefore, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not forbid the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
[0047] When an element is referred to as being “embodied thereon”, “engaged to”, “coupled to” or “communicatively coupled to” another element, it may be directly on, engaged, connected or coupled to the other element. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed elements.
[0048] In recent years, the automotive industry has undergone a transformative shift towards electrification, driven by the need for cleaner and more sustainable transportation solutions. High-electric power trains, commonly found in electric vehicles (EVs) and hybrid electric vehicles (HEVs), are at the forefront of this paradigm shift. These power trains rely on advanced battery technologies to store and deliver the high amounts of energy required for efficient and powerful electric propulsion.
[0049] Battery modules play a crucial role in the functionality and performance of these advanced battery technologies. These modules, composed of individual cells, serve as the energy storage units responsible for storing electrical energy during charging and delivering it to power the vehicle's electric motor during operation. The design of battery modules significantly influences the range, charging speed, and overall efficiency of electric vehicles.
[0050] Even though most commercial HEVs mainly use nickel-metal hydride (NiMH) batteries owing to their longer life cycles, it has been discovered that Lithium-ion batteries also have great potential and can be widely used in future HEVs. In fact, because of its advantages in volume, weight, and life, it is expected that lithium-ion batteries would become the mainstream in the future.
[0051] The lithium-ion cell will vent gases when subjected to high temperature, mechanical force, internal or external short circuits, etc. The cell venting is an exothermic reaction that raises the temperature of the cell & the venting gas. The high-temperature vent gas can encounter the neighboring cells in a battery module & can trigger a chain reaction of exothermic reaction leading to the phenomenon called, ‘thermal propagation’.
[0052] Most of the prior art shows that in the event of thermal propagation, the vent gases from the cell can escape the module from any direction. The end plates on both the sides are also designed to collect vent gases from any cell & exits the module via a common hole provided in the endplates or even the module housing. Therefore, recirculation of venting gases between cells occurs very often promoting cross-contamination and triggering venting in neighboring cells.
[0053] Therefore, there is a need to develop a battery module design for stopping thermal propagation that can alleviate the aforementioned drawbacks.
[0054] The present disclosure relates, in general, to the field of the design of battery modules. More particularly, embodiments of the present disclosure relate to a battery module design for stopping thermal propagation. The present disclosure focuses on enhancing safety and efficiency by addressing key issues related to thermal propagation management, venting, and contaminant prevention.
[0055] The present invention is about designing of a cell module in such a way that thermal propagation can be stopped at the cell level when a cell is venting.
[0056] The battery module 100 is designed such that the individual cells are always isolated using a thermal insulation pad 104. The battery module 100 also uses an epoxy resin 113 that blocks the cell venting on one side of the module & diverts the venting gas only to the other side of the module. The venting side of the module is designed to prevent the recirculation of the vent gas from one cell to another thereby stopping the thermal propagation.
[0057] The battery module 100 is classified into high voltage side & low voltage side. In the high voltage side of the module 100, a small volume is package protected for the epoxy resin pouring. The resin pouring region is formed between the bus bar frame assembly 106 & the isolation cover 112B of the high-voltage side end plate assembly.
[0058] A resin stopper 112D made of flexible polyurethane/silicone foam is assembled to the isolation cover 112B on this side of the second end plate assembly 112 to seal the epoxy resin 113 therein. The epoxy resin 113 closes the cell surface on this side of the module.
[0059] The design of battery module 100 for stopping thermal propagation of the present disclosure will now be described herein with reference to FIG.S 1 to 10.
[0060] FIG. 1 illustrates two perspective views, a front view, and two top views of either side of the battery module design for stopping thermal propagation and FIG. 2 illustrates a perspective view of a cell stack assembly 102 alongwith the first end plate assembly 110 and second end plate assembly 112 of the battery module 100 and the module housing 108 with a top surface 108A, a bottom surface 108B, and a side surfaces 108C in exploded view, in accordance with an embodiment of the present disclosure. The bus bar frame assembly 106 covers an upper surface along with front and rear sides of the cell stack assembly 102 such that from the front and rear sides of the cell stack assembly, cell tabs 102A of the cell stack assembly protrude from the bus bar frame 106. The module housing 108 has a top surface 108A, a bottom surface 108B, and side surfaces 108C for accommodating a coupled body of the cell stack assembly 102 and the bus bar frame aseembly 106.
[0061] FIG. 3A illustrates a cell stack assembly 102 with multitude of cells 102A enclosed within a metallic foil 102B, preferably made of aluminium and FIG. 3B depicts the cell stack assembly with potential region of cell venting through pockets 114 provided therein. The venting pockets 114 include angular venting passages at extreme ends of the cell stack assembly 102.
[0062] The pair of end plate assemblies 110, 112 is coupled to the front and rear sides of the cell stack assembly 102 in such a manner that the pair of end plate assemblies includes a first end plate assembly 110 through which cell venting gases escape from the cell stack assembly 102 and a second end plate assembly 112 configured to block the cell venting gases and divert the cell venting gases towards the first end plate assembly 110.
[0063] FIG. 4 illustrates a top view of the cell stack assembly 102 with thermal insulation pads 104, in accordance with an embodiment of the present disclosure.
[0064] In an aspect, the first end plate assembly 110 consists of an end plate housing 110 having multiple venting ports 114 through which cell venting gases escape from the cell stack assembly 102, an isolation cover coupled to the end plate housing to guide the cell venting gases toward the multiple venting ports 114, an isolation foil provided between the end plate housing that prevents the entry of any contaminants into the battery module, and a resin stopper assembled to the isolation cover to seal the first end plate assembly 110 with the cell stack assembly 102.
[0065] FIG. 5 illustrates different components of the second end plate assembly 112 in an exploded view in accordance with an embodiment of the present disclosure. In an aspect, the second end plate assembly 112 consists of an end plate housing 112A, an isolation cover 112B coupled to the end plate housing 112A, a resin pouring hole 112C formed on the top side of an intermediate assembly of said end plate housing 112A and the isolation cover 112B so as to pour epoxy resin in the intermediate assembly for blocking escape of the cell venting gases and a resin stopper 112D assembled to the intermediate assembly to seal the second end plate assembly 112 with the cell stack assembly 102.
[0066] In an aspect, the end plate housing 112A is a metal housing.
[0067] FIG. 6 illustrates the resin stopper interface 112D and FIG. 7 illustrates the high voltage (HV) side of the bus bar frame assembly alongwith the hole for resin pouring, in accordance with an embodiment of the present disclosure. In the HV side of the module, a small volume is package protected for the epoxy resin pouring. The resin pouring region is formed between the bus bar frame assembly 106 & the isolation cover 112B of the HV side end plate assembly.
[0068] A resin stopper (PU/silicon foam) is assembled to the HV side isolation cover to seal the epoxy resin 113 on the HV side of the module. In an aspect, the resin stopper 112C is made of a flexible polyurethane foam.
[0069] The epoxy resin 113 closes the cell surface on the HV side of the cell stack assembly.
[0070] FIG. 8 illustrates the cross-sectional view of the high voltage side of the bus bar frame assembly 102 to show the cavity meant for epoxy resin 113 and FIG. 9 illustrates a side and a magnified view of the cross-section of the high voltage side of the bus bar frame assembly to further depict how epoxy resin 113 blocks the cell venting on one side of the module, in accordance with an embodiment of the present disclosure.
[0071] FIG. 10 illustrates a side and a magnified view of the cross-section of the low voltage side of the bus bar frame assembly alongwith a top view of pockets 114 for cell gas venting and extended thermal insulation pads 105 for cell isolation provided therein, in accordance with an embodiment of the present disclosure.
[0072] FIG. 11A illustrates an enlarged cross-section view of the high voltage side of the bus bar frame assembly 106 and FIG. 11B illustrates an extended window 114A on the low voltage (LV) side of the bus bar frame assembly 106 for cell gas venting, in accordance with an embodiment of the present disclosure.
[0073] The foregoing description of the embodiments has been provided for purposes of illustration and is not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment but, are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
TECHNICAL ADVANCEMENTS AND ECONOMIC SIGNIFICANCE
[0074] The present disclosure described herein above has several technical advantages including, but not limited to, a battery module 100 for stopping thermal propagation, which:
• provides a battery module with a high-voltage end plate assembly design for epoxy resin pouring;
• provides the user(s) with a bus bar frame & end plate assembly design with a resin stopper to contain the epoxy resin;
• provides the user(s) with a thermal insulation pad between each cell of the battery module for cell isolation during venting;
• provides the user(s) with an extended window on the bus bar frame low-voltage side for cell gas venting;
• provides the user(s) with a battery module 100 preventing the entry of any contaminants into the battery module 100.
[0075] The present disclosure described herein above has several economic advantages including, but not limited to:
• cost-effectiveness, compared to the state-of-the-art equipment used for battery modules; and
• low-maintenance, compared to the state-of-the-art equipment used for battery modules.
[0076] The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0077] The foregoing description of the specific embodiments so fully reveals 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.
[0078] The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.
[0079] Any discussion of documents, acts, materials, devices, articles, or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
[0080] The numerical values mentioned for the various physical parameters, dimensions, or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary.
[0081] While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation. , Claims:WE CLAIM:
1. A battery module (100) for stopping thermal propagation, said battery module (100) comprises:
a cell stack assembly (102) including a plurality of cells (102A) with thermal insulation pads (104) therebetween to define a plurality of isolated venting pockets (114) for each of said plurality of cells (102A);
a bus bar frame assembly (106) covering an upper surface of said cell stack assembly (102) along with front and rear sides of said cell stack assembly (102), wherein from said front and rear sides, cell tabs (102A) of said cell stack assembly (102) protrude from said bus bar frame assembly (106);
a module housing (108) having a top surface (108A), a bottom surface (108B), and side surfaces (108C) for accommodating a coupled body of said cell stack assembly (102) and said bus bar frame assembly (106); and
a pair of end plate assemblies (110, 112) coupled to said front and rear sides of said cell stack assembly (102) where said cell tabs (102A) of said cell stack assembly (102) are disposed, wherein said pair of end plate assemblies (110, 112) includes a first end plate assembly (110) through which cell venting gases escape from the cell stack assembly (102) and a second end plate assembly (112) configured to block the cell venting gases and diverts the cell venting gases towards the first end plate assembly (110).
2. The battery module (100) as claimed in claim 1, wherein said first end plate assembly (110) consists of:
an end plate housing having multiple venting ports (114) through which cell venting gases escape from the cell stack assembly (102);
an isolation cover coupled to said end plate housing (110A) to guide the cell venting gases towards the multiple venting ports (114); and
an isolation foil provided between said end plate housing (110A) that prevents the entry of any contaminants into the battery module (100).
3. The battery module (100) as claimed in claim 2, wherein said isolation foil (110C) is made up of Polyethylene terephthalate (PET).
4. The battery module (100) as claimed in claim 1, wherein said second end plate assembly (112) consists of:
an end plate housing (112A);
an isolation cover (112B) coupled to said end plate housing (112A);
a resin pouring hole (112C) formed on the top side of an intermediate assembly of said end plate housing (112A) and said isolation cover (112B) so as to pour epoxy resin in said intermediate assembly for blocking escape of the cell venting gases; and
a resin stopper (112D) assembled to said intermediate assembly to seal said second end plate assembly (112) with said cell stack assembly (102).
5. The battery module (100) as claimed in claims 2 and 4, wherein said end plate housing (112A) is a metal housing.
6. The battery module (100) as claimed in claims 2 and 4, wherein said resin stopper (112D) is a flexible polyurethane foam.
7. The battery module (100) as claimed in claim 4, wherein said first end plate assembly (110) is coupled to a low voltage (LV) side of said bus bar frame assembly (102) and said second end plate assembly (112) is coupled to a high voltage (HV) side of said bus bar frame assembly (102).
8. The battery module (100) as claimed in claim 1, wherein said plurality of cells (102A) is connected in a combination of series and parallel connections through multiple bus bars of said bus bar frame assembly (106).
9. The battery module (100) as claimed in claim 1, wherein said plurality of thermal insulation pads (104) is arranged between two adjacent cells (102A) to thermally isolate each one of said plurality of cells (102A) from other cells.
10. The battery module (100) as claimed in claim 2, wherein said venting ports (114) include angular venting passages at extreme ends of the cell stack assembly (102).
11. The battery module (100) as claimed in claim 7, wherein the low voltage side of said bus bar frame assembly (106) is formed with an extended window (114A) for cell gas venting.

Dated this 06th day of December, 2023

_______________________________
MOHAN RAJKUMAR DEWAN, IN/PA – 25
of R.K.DEWAN & CO.
Authorized Agent of Applicant

TO,
THE CONTROLLER OF PATENTS
THE PATENT OFFICE, AT MUMBAI