Improved safety ventilation system for vehicular battery

Abstract

A battery pack (1) for a vehicle extending along longitudinal axes and comprising a casing (2) defining an internal space (V), which is isolated from the external environment, the battery pack (1) being provided with vent valves (3) configured to allow fluid communication between the internal space (V) and the external environment when the pressure in the internal space (V) reaches a predetermined value, the battery pack (3) comprising one or more coils (4) carried by the casing (2) and an emergency ventilation system (10) defining a vent space (E) configured to fluidly connect the internal space (V) to the relief valve vent (3).

Description

[0001] " IMPROVED SAFETY VENTILATION SYSTEM FOR VEHICULAR BATTERY"

[0002] Cross-Reference to Related Applications

[0003] This patent application claims priority from Italian patent application no . 102023000018363 filed on September 7 , 2023 , the entire disclosure of which is incorporated herein by reference .

[0004] Technical Sector

[0005] This invention concerns a ventilation system, in particular a safety ventilation system for electric batteries .

[0006] The preferred application of this invention, though not the only one , is in a safety ventilation system for vehicle batteries . This application will be referred to below by way of example .

[0007] Prior Art

[0008] Vehicles tend more and more to be electri fied in order to reduce emissions due to the use of internal combustion engines or to completely replace these ones .

[0009] To this end, hybrid, electric, or hydrogen vehicles are used more and more . These vehicles , as known, store electricity used for the purpose of driving / operating the vehicle operating systems or stored by generators in battery systems .

[0010] These battery systems comprise one or more battery units housed inside a casing that isolates them from the external environment and allows the neces sary wiring to be housed . Again, as known, electric batteries used in these vehicles are electrochemical storage devices that , during use , when charging, or discharging, tend to heat up .

[0011] It is possible that the internal heating within the batteries reaches such levels as to generate a phenomenon called "thermal runaway" in which the temperature triggers exothermic reactions that further raise the temperature and, thus , as a result lead to disastrous consequences such as explosions or fires .

[0012] In particular, these explosions involve the propagation of free flames and particulate that are particularly hazardous both for vehicle passengers and for the spreading of the fire to other parts of the vehicle or around it .

[0013] In order to improve the safety of such battery systems , rule EC R100 . 3 sets forth very strict criteria regarding the propagation of free flames and particulate outside the casing housing the batteries .

[0014] There is a need, therefore , to improve known battery systems in order to limit the escape of free f lames and particulate from the same , avoiding hazards connected to the prior art systems described above .

[0015] The purpose of this invention is to meet the needs outlined above in an optimal and inexpensive way .

[0016] Summary of the Invention

[0017] The above-mentioned purpose is achieved with a safety ventilation system and battery pack as claimed in the attached claims , which are an integral part of this description .

[0018] Brief Description of the Drawings

[0019] For a better understanding of this invention, a preferred embodiment is described below by way of non-limiting example and with reference to the accompanying drawings , wherein :

[0020] • Figure 1 is a simpli fied perspective view of a battery pack according to the invention;

[0021] • Figure 2 is a simpli fied perspective view with parts removed for clarity of an emergency ventilation system for a battery pack according to a first embodiment of the invention;

[0022] • Figure 3 is a perspective view of a part of the emergency ventilation system in Figure 2 ;

[0023] • Figure 4 is a simpli fied perspective view with parts removed for clarity of an emergency ventilation system for a battery pack according to a second embodiment of the invention;

[0024] • Figure 5 is a perspective view of a part of the emergency ventilation system in Figure 4 ; and

[0025] • Figures 6A - 6B correspond to Figures 3 and 5 with lines introduced to highlight the passage of fluid in the emergency ventilation system according to the respective embodiments of the invention .

[0026] Detailed Description of the Invention

[0027] In the attached figures , reference number 1 indicates a battery pack for a vehicle (not illustrated) . The battery pack 1 comprises a casing 2 delimiting an internal space V designed to house multiple batteries 4 .

[0028] In particular, the casing 2 may be made of two portions 2 ' , 2 ' ' connected to each other, in use , and which can be selectively separated, for example to enable the inspection of the space V .

[0029] At least one of the two portions 2 ' , 2 ' ' is provided with one or more vent valves 3 configured to allow fluidic communication between the internal space V and the external environment i f the pressure in the internal space V reaches a predetermined level , for example because of combustion due to thermal runaway .

[0030] In the internal space V, isolated from the external environment via the casing 2 , the batteries 4 are supported by one of the two portions 2 ' , 2 ' ’ advantageously the lower one 2 ’ ’ , and connected to each other by a fastening system 5 not further described for brevity .

[0031] For the sake of clarity, it is noted that the battery pack 1 has a basically square shape that extends along a pair of longitudinal A and transverse B axes , which are perpendicular to each other, and extends vertically along a vertical axis C perpendicular to the longitudinal A and transverse B axes .

[0032] The battery pack 1 also comprises an emergency ventilation system 10 according to the invention configured to fluidly connect the internal space V to the environment external to the battery pack 1 via vent valves 3 .

[0033] Advantageously, the emergency ventilation system 10 is housed inside the internal space V adj acent to the batteries 4 .

[0034] Speci fically, the emergency ventilation system 10 is placed vertically adj acent to the batteries 3 , in particular vertically above the batteries 4 and in particular above the fastening system 5 .

[0035] The emergency ventilation system is preferably placed adj acent to the batteries 4 , i . e . in particular above the fastening system 5 , without contact with these, i . e . defining a gap along the vertical axis C .

[0036] The emergency ventilation system 10 advantageously comprises a lid 11 and a base portion 12 connected to each other to define a vent space E fluidly connecting the internal space V to the vent valves 3 .

[0037] Speci fically, the base portion 12 is adj acent to the batteries 4 , in particular vertically facing above these along the vertical axis C and extends largely along the longitudinal axis A.

[0038] Speci fically, the vent space E comprises an inlet portion 13 fluidly connected to the internal space V, for example via an opening in the base portion 12 .

[0039] The vent space E comprises an outlet portion 14 fluidly connected to the vent valves 3 as better described below .

[0040] The inlet portion 13 and the outlet portion 14 are connected by an intermediate portion 16 extending along the longitudinal axis A.

[0041] According to the embodiment described, the inlet portion 13 is delimited by the lid 11 that extends further along the axis A than the base portion 12 thus defining an opening 13 ' extending along the transverse axis B fluidly in communication with the internal space V .

[0042] The vent space E is vertically delimited by a pair of main walls 16a, 16b facing each other along the vertical axis C and a pair of longitudinal walls 16c extending parallel along the longitudinal axis A. Advantageously, the main walls 16a, 16b are rectangular-shaped so as to define a vent space E that is basically parallelepipedal .

[0043] Speci fically, the main walls 16a, 16b are part of , respectively, the lid 11 and the base portion 12 , while the longitudinal walls 16c may extend from one of these . Speci fically, in the embodiment described, the longitudinal walls 16c extend starting from the lower main wall 16b that is part of the base portion 12 while the lid 11 comprises the sole upper main portion 16a .

[0044] According to the embodiment above , the upper main wall 16a extends longitudinally, i . e . along the axis A, further than the lower main wall 16b, thus defining the opening 13 ' .

[0045] In the embodiment illustrated, the vent valves 3 are placed vertically below the vent space E ; thus , the outlet portion 14 is shaped so as to enable the fluidic connection along this di f ference in height .

[0046] In the embodiment described, the outlet portion 14 is delimited by a pair of vertical walls 14a' , 14a' ' facing each other along the vertical axis C and vertically continuous starting from the upper and lower main walls 16a, 16b and from a pair of transverse walls 14b' , 14b' ' facing each other along the direction of the axis A, respectively connected to the vertical walls 14 a' , 14a' ' on one side , for example via a curved portion, and connected to each other by a bottom portion .

[0047] One lateral wall further connects the pair of vertical and transverse walls connected to respective lateral walls 16c delimiting the central portion 16 .

[0048] In the embodiment described, the upper vertical wall 14a' and the external transverse wall 14b' are part of the lid 11 like the bottom wall , whi le the lower vertical wall 14a' ' and the internal transverse wall 14b' ' are part of the bottom portion 12 .

[0049] Again, in the embodiment described, the vertical walls 14a' , 14a' ' extend further along the direction of the transverse axis B than the main walls 16a, 16b defining the intermediate portion 16 .

[0050] Speci fically, the external transverse wall 14b' defines multiple openings 15 configured to house part of the vent valves 3 .

[0051] Advantageously, the upper main wall 16a has a discontinuous pro file , i . e . , it de fines one or more lowered portions 16d, i . e . vertically closer than the rest of the upper main wall 16a to the lower main wall 16d .

[0052] Similarly, the external transverse wall 14b' defines one or more recessed portions 14c, i . e . longitudinally closer than the rest of the external transverse wall 14b' to the internal transverse wall 14b' ' .

[0053] Speci fically, the recessed portions 14c are provided between two openings 15 adj acent along the transverse axis B so as to facilitate the flow of fluid towards them .

[0054] Advantageously, the emergency ventilation system 10 comprises multiple deflector means 17 placed in the intermediate portion 16 and configured to change the direction of a fluid passing from the inlet portion 13 to the outlet portion 14 according to the direction along at least one of the longitudinal A, transverse B, and / or vertical C axes .

[0055] As a result , the path of the combustion gas fluid of the coils 4 , in the event of thermal runaway, is greater than the extension along the longitudinal and transverse axes A, B given that this path is deviated by the deflector means 17 and by the position of the openings 15.

[0056] In particular, the deflector means 17 comprise baf fles 18 operationally interposed between the upper and lower main walls 16a, 16b, forcing the passage of the fluid passing from the inlet portion 13 to the outlet portion 14 along a speci fic direction .

[0057] These baf fles 18 may be solid wall s and, thus , totally deflecting the fluid hitting them and / or comprise a grilled portion 19 configured to enable , " filtered" , the passage of the fluid through it .

[0058] In the first embodiment , illustrated in Figures 2 and 3 , the baf fles 18 are continuously interposed along the flow of fluid passing from the inlet portion 13 to the outlet portion 14 .

[0059] Speci fically, in this embodiment , the emergency ventilation system 10 comprises a first baf fle 18 fluidly interposed between the inlet portion 13 and the intermediate portion 16 , a second baf fle 18 fluidly interposed between the outlet portion 14 and the intermediate portion 16 and a pair of baf fles 18 fluidly interposed within the intermediate portion 16 between the first and second baf fle 18 .

[0060] Advantageously, one portion of the baf fles 18 is equipped with a grilled portion 19 configured to enable the passage of fluid through it and, thus , through the baf fle

[0061] 18 .

[0062] Speci fically, these grilled portions 19 are offset between them transversely along the direction of the longitudinal axis A so that the fluid passing through a grilled portion 19 hits a solid baf fle 18 portion turned longitudinally and is forced to change direction transversely to pass an adj acent grilled portion 19 .

[0063] As can be seen from the figures , the grilled portions

[0064] 19 may optionally have di f ferent meshes . In particular, the first two grilled portions 19 , according to the direction in which the fluid flows starting from the inlet portion 13 , are defined by vertical openings that are basically, equally spaced apart from each other, while the last two grilled portions 19 , again in the same direction in which the fluid flows, are made using inclined lines that intersect defining a kind of grid.

[0065] If present, the lowered portions 16d are preferably interposed between the first baffle 18 and the pair of intermediate baffles 18 and between the second baffle 18 and the pair of intermediate baffles 18.

[0066] In the second embodiment, illustrated in Figures 4 and 5, at least part of the baffles 18 are interposed along the flow of the fluid passing from the inlet portion 13 to the outlet portion 14 in a discontinuous way, i.e. not necessarily continuously connected between the lateral walls 16c as in the first embodiment described above.

[0067] Specifically, in this embodiment, the emergency ventilation system 10 comprises a first baffle 18 fluidly interposed between the inlet portion 13 and the intermediate portion 16, a second baffle 18 fluidly interposed between the outlet portion 14 and the intermediate portion 16 and multiple baffles 18, four in particular, fluidly interposed within the intermediate portion 16 between the first and second baffle 18.

[0068] Advantageously, the first and second baffle 17 are equipped, over the entire extension along the transverse axis B, with a grilled portion 19.

[0069] As can be seen from the figures, the grilled portions 19 may optionally have different meshes. In particular, the grill 19 of the first baffle is made of multiple openings extending parallel to the longitudinal axis B while the grill 19 of the second baf fle 18 is made using inclined lines that intersect defining a kind of grid .

[0070] The multiple baf fles 18 between the first and second baf fle 18 extend starting from the lateral walls 16c towards the opposite lateral wall 16c on part of this di stance or along the transverse axis B between these lateral walls 16c without j oining these at any terminal edge .

[0071] In particular, a third baf fle 18 comprises two portions extending from the lateral walls 16c, the one towards the other, leaving a free space in the space between them comprised along the axis B and a fourth baf fle 18 comprises a single portion extending along the axis B between the lateral walls 16c, leaving respective free spaces adj acent to the lateral walls 16c, i . e . without j oining up . In addition, this fourth baf fle 18 is placed in the free space defined by the third baf fle 18 .

[0072] A fi fth and sixth baf fle 18 are made similarly to what is described above so that the free spaces that enable the passage of fluid alternate with baf fles 18 along the longitudinal axis A.

[0073] I f present , the lowered portions 16d are preferably interposed between the first baf fle 18 and multiple intermediate baf fles 18 and between the second baf fle 18 and multiple intermediate baf fles 18 .

[0074] The operation of the embodiment of the safety ventilation system according to the invention described above is the following . As illustrated in Figures 6A and 6B, in the event of over-heating and thermal runaway, the combustion gases of the batteries 4 would accumulate in the internal space V and would tend to occupy the vent space E towards the valves 3 . Once a predetermined pressure was reached, the valves 3 would tend to open, enabling the exit of these combustion gases .

[0075] In the event of serious thermal runaway, the quantity of combustion gases provided and potentially of free f lames is considerable and is channelled into the vent space E thanks to the deflector means 17 , thus reducing the speed of combusted gases and the propagation of free flames .

[0076] In the operation of the first embodiment ( Figure 6A) , the combustion gases and any flames entering the opening 13 ' pass through the grill 19 of the first baf fle 18 and continuously change direction along the transverse axis B to cross the succession of grills 18 provided along the longitudinal direction A until exiting from the second baf fle

[0077] 18 and passing from the openings 15 via the vent valves 3 towards the external environment .

[0078] In the operation of the second embodiment ( Figure 6B ) , the combustion gases and any flames entering from the opening 13 ' pass through the grill 19 of the first baf fle 18 and, from there , are centrally channelled from the third baf fle to hit the fourth and change direction transversely, repeating this path twice before passing through the grill

[0079] 19 of the second baf fle 18 towards the openings 15 .

[0080] In both embodiments , since the openings 15 are at a lower level than the path of the intermediate portion 16 , the combustion gases change path again along the vertical axis C .

[0081] I f the lowered portions 16d and the recessed portions 14c are included, these contribute to deviating the flow of the combustion gases , encouraging the continuity of this combustion gas flow rate .

[0082] From the above , the advantages of a safety ventilation system and battery pack according to the invention are clear .

[0083] Thanks to the emergency ventilation system proposed, it is possible to direct the flow of combustion gases , thus of related particulate and free flames , along a predetermined path towards the vent valves .

[0084] In particular, thanks to the fact that this path is much greater than the extension of the battery pack thanks to the presence of the deflector means , the particulates and free flames tend to remain trapped in the vent space , thus reducing potential damage to things or people near the battery pack . In particular, the escape of particulate or free flames is largely prevented .

[0085] In particular, the configurations proposed are optimised for various types and si zes of batteries .

[0086] Speci fically, the second embodiment of fers greater turbulence and a smaller probability of obstruction of the grills provided in the baf fles and, thus , a lesser risk of mal functioning in the event of serious thermal runaway compared to the first embodiment . Finally, it is clear that changes may be made to the safety ventilation system and battery pack, and variations produced thereto, according to this invention that, in any case, do not depart from the scope of protection defined by the claims.

[0087] For example, the shape of the emergency ventilation system may vary, like the shape of the battery pack or the path provided by the deflector means.

[0088] In fact, although not described in detail but clear from the structure of the description and the claims, the emergency ventilation system could be housed outside the internal space V.

[0089] In particular, other configurations of the deflector means in the vent space E may be envisaged, as the grills described may be envisaged with a different shape. Like, for example, inclined baffles or grills and baffles in portions alternating between them.

[0090] Again, the two embodiments described may be combined, thus providing different configurations or grills with different forms of opening compared to what is illustrated.

Claims

CLAIMS1.- A battery pack (1) for a vehicle, said battery pack (1) extending along respective longitudinal (A) and transverse (B) axes and comprising a casing (2) defining an internal space (V) , which is isolated from the external environment , said battery pack (1) comprising vent valves(3) configured to allow fluid communication between said internal space (V) and said external environment when the pressure in said internal space (V) reaches a predetermined value, said battery pack (1) comprising one or more coils(4) carried by said casing (2) and an emergency ventilation system (10) defining a vent space (E) configured to fluidly connect said internal space (V) to said relief valve vent (3) wherein said emergency ventilation system (10) comprises a base portion (12) and a lid (11) defining said vent space (E) , said vent space (E) comprising at least an inlet portion (13) equipped with an opening (13' ) fluidly connected to said internal space (V) , an outlet portion (14) fluidly connected to said vent valves (3) and an intermediate portion (16) connecting said inlet (13) and outlet (14) portions, wherein said intermediate portion (16) is delimited by an upper main wall (16a) , a lower main wall (16b) and a pair of lateral walls (16c) , which form the walls of one of said lid (11) and said base portion (12) , said pair of side portions (16c) connecting said upper and lower main walls (16a, 16b) , wherein said inlet portion (13) is delimited by said upper main wall (16a) extending further along saidlongitudinal axis (A) than said lower main wall (16b) , thus defining said opening (13' ) .2.- The battery pack according to claim 1, wherein said emergency ventilation system (10) is housed within said internal space (V) and adjacent to said one or more batteries (4) .3.- The battery pack according to claim 2, wherein said emergency ventilation system (10) is placed above, along a vertical axis (C) perpendicular to said longitudinal and transversal axes (A, B) with respect to said one or more batteries ( 4 ) .4.- The battery pack according to claim 1 or 2, wherein said emergency ventilation system (10) is adjacent to said one or more batteries (4) at a distance from the latter.5.- The battery pack according to one of the previous claims, wherein said outlet portion (14) is delimited by a pair of vertical walls (14a', 14a' ' ) facing each other along said vertical axis (C) and each connected to a respective one of said upper and lower main walls (16a, 16b) and by a pair of transverse walls (14b', 14b' ' ) facing each other along the direction of said longitudinal axis (A) and respectively connected to a respective one of said vertical walls (14a' , 14a' ' ) .6.- The battery pack according to claim 5, wherein said transverse walls (14b', 14b' ' ) define openings (15) configured to house said vent valves (3) .7 The battery pack according to claim 6, wherein saidopenings (15) are placed vertically lower down along the vertical axis (C) than said lower main wall (16b) .8.- The battery pack according to one of the previous claims, wherein said emergency ventilation system (10) comprises deflector means (17) , which are housed in said vent space (E) and are carried by at least one of said lids (11) and said base portion (12) and are configured to vary the direction of the flow of gases flowing from said inlet portion (13) towards said outlet portion (14) along at least one of said longitudinal, transversal and vertical axes (A,B,C) .9.- The battery pack according to claim 8, wherein said baffle means (17) comprise baffles (18) extending along said transversal axis (B) .10.- The battery pack according to claim 9 when dependent on 6, wherein said baffles (18) extend over at least part of the extension of said upper and lower main walls (16a, 16b) .11.- The battery pack according to one of claims 8 or 9, wherein said baffles (17) comprise a grilled portion (19) .12.- The battery pack according to claim 11, wherein said grilled portion (19) has lattice openings or openings arranged parallel along one of said longitudinal, transversal, or vertical axes (A, B, C) .13.- The battery pack according to one of claims from 9 to 12, wherein said baffles (17) are arranged transversely staggered with respect to each other along the direction ofsaid longitudinal axis (A) .14.- The battery pack according to one of the preceding claims, in which one of said upper and lower main walls (16a, 16b) defines a lowered portion (16d) along said vertical axis (C) .

15. The battery pack according to one of the preceding claims, wherein one of said transverse walls (14b', 14b' ' ) defines a recessed portion (14c) along said longitudinal axis (A) .

Images