Improved safety exhaust system for vehicle battery

Abstract

Battery pack (1) for a vehicle, extending along a longitudinal axis and comprising a housing (2) defining an interior space (V) isolated from an external environment, the battery pack (1) being provided with an exhaust valve (3) configured to allow fluid communication between the interior space (V) and the external environment when a pressure in the interior space (V) reaches a predetermined value, the battery pack (3) comprises one or more coils (4) carried by the housing (2) and an emergency exhaust system (10) defining an exhaust space (E) configured to fluidly connect the interior region (V) to the relief valve exhaust (3).

Description

Improved safety venting system for vehicle batteries

[0001] Cross-references to related applications

[0002] This patent application claims priority to Italian Patent Application No. 102023000018363, filed on 7 September 2023, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] This invention relates to venting systems, and in particular to safety venting systems for batteries.

[0004] A preferred application—but not the only application—of this invention is a safety venting system for vehicle batteries. This application will be illustrated below by way of example. Background Technology

[0005] Vehicles are increasingly trending towards electrification in order to reduce emissions from or completely replace internal combustion engines.

[0006] As a result, the use of hybrid, electric, or hydrogen-powered vehicles is increasing. These vehicles, as is known, store electricity used to drive / operate the vehicle's operating system or store electricity in a battery system via a generator.

[0007] These battery systems include one or more battery cells housed within a housing that isolates these battery cells from the external environment and allows for the housing of necessary wiring.

[0008] Similarly, as is known, the batteries used in these vehicles are electrochemical storage devices, which tend to generate heat during use, when charging or discharging.

[0009] The internal heat generated within a battery can reach levels that produce a phenomenon known as "thermal runaway," in which temperature triggers an exothermic reaction that further increases the temperature and can lead to catastrophic consequences such as explosions or fires.

[0010] In particular, these explosions involve the spread of free flames and particulate matter, which is especially dangerous for vehicle passengers and for the fire to spread to other parts of the vehicle or the surrounding area.

[0011] To improve the safety of such battery systems, regulation EC R100.3 sets very strict standards for the propagation of free flames and particulate matter outside the battery casing.

[0012] Therefore, there is a need to improve known battery systems to limit the escape of free flames and particulate matter from the battery system, thereby avoiding the dangers associated with the aforementioned prior art systems.

[0013] The purpose of this invention is to meet the requirements outlined above in the best and lowest cost manner. Summary of the Invention

[0014] The above objectives are achieved by the safety venting system and battery pack claimed in the appended claims, which are integral parts of this specification. Attached Figure Description

[0015] To better understand the present invention, preferred embodiments are described below by way of non-limiting examples and with reference to the accompanying drawings, in which:

[0016] ● Figure 1 is a simplified perspective view of the battery pack according to the present invention;

[0017] ● Figure 2 is a simplified perspective view of an emergency venting system for a battery pack according to a first embodiment of the present invention, in which several components have been removed for clarity.

[0018] ● Figure 3 is a perspective view of a portion of the emergency exhaust system in Figure 2;

[0019] ● Figure 4 is a simplified perspective view of an emergency venting system for a battery pack according to a second embodiment of the present invention, in which several components have been removed for clarity.

[0020] ● Figure 5 is a perspective view of a portion of the emergency exhaust system shown in Figure 4; and

[0021] ● Figures 6A to 6B correspond to Figures 3 and 5, in which lines are introduced to highlight the fluid passages in the emergency exhaust system according to the corresponding embodiments of the invention. Detailed Implementation

[0022] In the accompanying drawings, reference numeral 1 indicates a battery pack for a vehicle (not shown). The battery pack 1 includes a housing 2 defining an internal space V, which is designed to accommodate a plurality of batteries 4.

[0023] Specifically, the housing 2 may consist of two parts 2', 2'', which are connected to each other during use and can be selectively separated, for example, to enable inspection of the space V.

[0024] At least one of the two sections 2', 2'' is provided with one or more exhaust valves 3, which are configured to allow fluid communication between the interior space V and the external environment when the pressure in the interior space V reaches a predetermined level (e.g., due to combustion caused by thermal runaway).

[0025] In the internal space V isolated from the external environment by the housing 2, the battery 4 is supported by one of the two parts 2', 2'', advantageously by the lower part 2'', and connected to each other by a fastening system 5, which will not be described further for the sake of brevity.

[0026] For clarity, it should be noted that the battery pack 1 has a substantially square shape that extends along a pair of longitudinal axes A and transverse axes B that are perpendicular to each other, and extends vertically along a vertical axis C that is perpendicular to the longitudinal axes A and transverse axes B.

[0027] The battery pack 1 also includes an emergency venting system 10 according to the invention, which is configured to fluidly connect the internal space V to the external environment of the battery pack 1 via an venting valve 3.

[0028] Advantageously, the emergency exhaust system 10 is housed within the interior space V adjacent to the battery 4.

[0029] Specifically, the emergency exhaust system 10 is arranged vertically adjacent to the battery 4, particularly above the battery 4, and particularly above the fastening system 5.

[0030] The emergency venting system is preferably arranged adjacent to the battery 4, specifically above the fastening system 5, but not in contact with it, i.e., with a gap defined along the vertical axis C.

[0031] The emergency exhaust system 10 advantageously includes a cover 11 and a base 12 connected to each other to define an exhaust space E that fluidly connects the internal space V to the exhaust valve 3.

[0032] Specifically, the base 12 is adjacent to the battery 4, particularly above the battery 4 along the vertical axis C, and extends mainly along the longitudinal axis A.

[0033] Specifically, the exhaust space E includes an inlet portion 13, which is fluidly connected to the interior space V, for example, via an opening in the base 12.

[0034] The exhaust space E includes an outlet portion 14 which is fluidly connected to the exhaust valve 3, as better described below.

[0035] The inlet portion 13 and the outlet portion 14 are connected by an intermediate portion 16 extending along the longitudinal axis A.

[0036] According to the described embodiment, the inlet portion 13 is defined by a cover 11 that extends further along axis A than the base 12, thus defining an opening 13' that extends along transverse axis B and is in fluid communication with the interior space V.

[0037] The exhaust space E is vertically defined by a pair of main walls 16a and 16b facing each other along the vertical axis C and a pair of longitudinal walls 16c extending parallel to each other along the longitudinal axis A. Advantageously, the main walls 16a and 16b are rectangular to define the exhaust space E, which is essentially a parallelepiped.

[0038] Specifically, the main walls 16a and 16b are part of the cover 11 and the base 12, respectively, while the longitudinal wall 16c may extend from one of them. Specifically, in the described embodiment, the longitudinal wall 16c extends from the lower main wall 16b, which is part of the base 12, while the cover 11 includes a separate upper main portion 16a.

[0039] According to the above embodiment, the upper main wall 16a extends further longitudinally, i.e., along axis A, than the lower main wall 16b, thus defining the opening 13'.

[0040] In the illustrated embodiment, the exhaust valve 3 is arranged vertically below the exhaust space E; therefore, the outlet portion 14 is shaped to enable fluid connection along the height difference.

[0041] In the described embodiment, the outlet portion 14 is defined by a pair of vertical walls 14a', 14a'' and a pair of transverse walls 14b', 14b''. The pair of vertical walls 14a', 14a'' face each other along the vertical axis C and are vertically continuous from the upper main wall 16a and the lower main wall 16b. The pair of transverse walls 14b', 14b'' face each other along the direction of axis A and are respectively connected to the vertical walls 14a', 14a'' on one side, for example, via a curved portion and connected to each other through the bottom.

[0042] One sidewall is also connected to a pair of vertical and horizontal walls, which are connected to the respective sidewall 16c, thereby defining the central portion 16.

[0043] In the described embodiment, the upper vertical wall 14a' and the outer transverse wall 14b' are part of the cover 11, like the bottom wall, while the lower vertical wall 14a'' and the inner transverse wall 14b'' are part of the bottom 12.

[0044] Similarly, in the described embodiment, the vertical walls 14a', 14a'' extend further along the direction of the transverse axis B than the main walls 16a, 16b that define the intermediate portion 16.

[0045] Specifically, the outer transverse wall 14b' defines a plurality of openings 15, which are configured to accommodate part of the exhaust valve 3.

[0046] Advantageously, the upper main wall 16a has a discontinuous profile, that is, it defines one or more lower portions 16d, that is, vertically closer to the lower main wall 16d than the rest of the upper main wall 16a.

[0047] Similarly, the outer transverse wall 14b' defines one or more recessed portions 14c, which are longitudinally closer to the inner transverse wall 14b'' than the rest of the outer transverse wall 14b'.

[0048] Specifically, the recessed portion 14c is disposed between two adjacent openings 15 along the transverse axis B to facilitate fluid flow to them.

[0049] Advantageously, the emergency exhaust system 10 includes a plurality of deflector devices 17 arranged in the intermediate portion 16 and configured to change the direction of fluid flowing from the inlet portion 13 to the outlet portion 14 according to the direction of at least one of the longitudinal axis A, the transverse axis B and / or the vertical axis C.

[0050] Therefore, in the event of thermal runaway, the path of the combustion gas fluid in coil 4 is greater than the extension along the longitudinal axis A and the transverse axis B, because the path is deflected by the position of the deflector device 17 and the opening 15.

[0051] Specifically, the deflector device 17 includes a baffle 18 operably inserted between the upper main wall 16a and the lower main wall 16b, thereby forcing fluid to flow in a specific direction from the inlet portion 13 to the outlet portion 14.

[0052] These baffles 18 may be solid walls, thus completely deflecting the fluid impacting them, and / or include grid portions 19 configured to allow the fluid to be “filtered” through.

[0053] In the first embodiment shown in Figures 2 and 3, the baffle 18 is continuously inserted along the fluid flow from the inlet portion 13 to the outlet portion 14.

[0054] Specifically, in this embodiment, the emergency exhaust system 10 includes a first baffle 18 fluidly inserted between the inlet portion 13 and the intermediate portion 16, a second baffle 18 fluidly inserted between the outlet portion 14 and the intermediate portion 16, and a pair of baffles 18 fluidly inserted between the first baffle 18 and the second baffle 18 within the intermediate portion 16.

[0055] Advantageously, a portion of the baffle 18 is equipped with a grille portion 19, which is configured to allow fluid to pass through it and thus through the baffle 18.

[0056] Specifically, these grid portions 19 are laterally offset between them along the direction of the longitudinal axis A, such that fluid passing through the grid portions 19 impacts the longitudinally rotating solid baffle portion 18 and is forced to change direction laterally to pass through the adjacent grid portions 19.

[0057] As can be seen from the figure, the grid sections 19 may optionally have different grids. In particular, the first two grid sections 19 are defined by vertical openings that are substantially equidistant from each other, depending on the direction in which the fluid flows from the inlet section 13, while the latter two grid sections 19 are similarly formed in the same direction of fluid flow using intersecting diagonal lines that define a certain grid.

[0058] If present, the lower portion 16d is preferably inserted 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.

[0059] In the second embodiment shown in Figures 4 and 5, at least a portion of the baffle 18 is inserted discontinuously along the fluid flow from the inlet portion 13 to the outlet portion 14, i.e., it does not need to be continuously connected between the sidewalls 16c as in the first embodiment described above.

[0060] Specifically, in this embodiment, the emergency exhaust system 10 includes a first baffle 18 fluidly inserted between the inlet portion 13 and the intermediate portion 16, a second baffle 18 fluidly inserted between the outlet portion 14 and the intermediate portion 16, and a plurality of baffles 18 fluidly inserted between the first baffle 18 and the second baffle 18 within the intermediate portion 16, particularly four baffles.

[0061] Advantageously, the first and second baffles 17 are equipped with grille portions 19 along the entire extension of the transverse axis B.

[0062] As can be seen from the figure, the grille portion 19 may optionally have different grids. In particular, the grille 19 of the first baffle is formed by a plurality of openings extending parallel to the longitudinal axis B, while the grille 19 of the second baffle 18 is formed using intersecting diagonal lines that define a certain grid.

[0063] The plurality of baffles 18 between the first baffle 18 and the second baffle 18 extend from the sidewall 16c toward the opposite sidewall 16c at a portion of the distance from the sidewall 16c to the opposite sidewall 16c, or extend along the transverse axis B between these sidewalls 16c without connecting these sidewalls at any end edge.

[0064] Specifically, the third baffle 18 comprises two portions extending from the sidewall 16c, one facing the other, leaving free space along axis B in the space between them, and the fourth baffle 18 comprises a single portion extending along axis B between the sidewalls 16c, leaving a corresponding free space adjacent to the sidewall 16c, i.e., not connecting to the sidewall 16c. Furthermore, the fourth baffle 18 is arranged within the free space defined by the third baffle 18.

[0065] The fifth baffle 18 and the sixth baffle 18 are formed similarly to those described above, such that the free space through which the fluid can pass alternates with the baffle 18 along the longitudinal axis A.

[0066] If present, the lowering portion 16d is preferably inserted between the first baffle 18 and the plurality of intermediate baffles 18 and between the second baffle 18 and the plurality of intermediate baffles 18.

[0067] The operation of the safety exhaust system according to the present invention described above is as follows.

[0068] As shown in Figures 6A and 6B, under conditions of overheating and thermal runaway, combustion gases from battery 4 will accumulate in the internal space V and tend to occupy the exhaust space E facing valve 3. Once a predetermined pressure is reached, valve 3 will tend to open, allowing these combustion gases to escape.

[0069] In the event of severe thermal runaway, the amount of combustion gases and potential free flames supplied is considerable and is directed into the exhaust space E by the deflector device 17, thereby reducing the velocity of the combustion gases and the propagation of the free flames.

[0070] In the operation of the first embodiment (Fig. 6A), the combustion gas and any flame entering the opening 13' pass through the grille 19 of the first baffle 18 and continuously change direction along the transverse axis B to pass through a series of grilles 18 arranged along the longitudinal direction A until it leaves the second baffle 18 and goes to the external environment from the opening 15 via the exhaust valve 3.

[0071] In the operation of the second embodiment (Fig. 6B), the combustion gas and any flame entering from the opening 13' pass through the grille 19 of the first baffle 18 and are guided centrally from there from the third baffle to impact the fourth baffle and change direction laterally. This path is repeated twice before passing through the grille 19 of the second baffle 18 toward the opening 15.

[0072] In both embodiments, since the opening 15 is at a level below the path of the middle portion 16, the combustion gas changes its path again along the vertical axis C.

[0073] If the reduced portion 16d and the recessed portion 14c are included, these portions help to deflect the flow of combustion gases, thereby promoting the continuity of the combustion gas flow rate.

[0074] In summary, the advantages of the safety venting system and battery pack according to the present invention are obvious.

[0075] The proposed emergency exhaust system can guide the flow of combustion gases, including the associated particulate matter and free flame, along a predetermined path toward the exhaust valve.

[0076] In particular, because the path is much larger than the battery pack's extension due to the presence of the deflector device, particulate matter and free flames are tended to be trapped in the exhaust space, thus reducing potential harm to objects or people near the battery pack. Specifically, the escape of particulate matter or free flames is largely prevented.

[0077] In particular, the proposed configuration has been optimized for use with batteries of various types and sizes.

[0078] Specifically, compared to the first embodiment, the second embodiment provides greater turbulence and a lower likelihood of grid blockage in the baffle, and therefore a lower risk of failure in the event of severe thermal runaway.

[0079] Finally, it is clear that, according to the present invention, modifications can be made to the safety venting system and the battery pack, as well as the variations thereof, without exceeding the scope of protection defined by the claims in any event.

[0080] For example, the shape of an emergency exhaust system can vary, such as the shape of a battery pack or the path provided by a deflector device.

[0081] In fact, although not described in detail, it is clear from the structure of the specification and claims that the emergency exhaust system can be housed outside the internal space V.

[0082] In particular, other configurations of the deflector device in the exhaust space E can be envisioned, since the described grille can be conceived as having different shapes. For example, inclined baffles or grilles and baffles partially alternating between them.

[0083] Similarly, the two described embodiments can be combined to provide different configurations or grilles with different opening forms compared to those shown.

Claims

1. A battery pack (1) for a vehicle, the battery pack (1) extending along respective longitudinal axes (A) and transverse axes (B), and including a housing (2) defining an internal space (V) isolated from an external environment, the battery pack (1) including an exhaust valve (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 (1) including one or more coils (4) carried by the housing (2) and an emergency exhaust system (10) defining an exhaust space (E) configured to fluidly connect the internal region (V) to the pressure relief valve exhaust element (3), wherein, The emergency exhaust system (10) includes a base (12) and a cover (11) defining the exhaust space (E), the exhaust space (E) including at least an inlet portion (13) equipped with an opening (13') fluidly connected to the interior space (V), an outlet portion (14) fluidly connected to the exhaust valve (3), and an intermediate portion (16) connecting the inlet portion (13) and the outlet portion (14), wherein the intermediate portion (16) is formed by an upper main wall (16a). The upper main wall (16a) and the lower main wall (16b) are defined by a pair of side walls (16c), which form the walls of one of the cover (11) and the base (12). The pair of side portions (16c) connect the upper main wall (16a) and the lower main wall (16b). The entrance portion (13) is defined by the upper main wall (16a), which extends further along the longitudinal axis (A) than the lower main wall (16b), thereby defining the opening (13').

2. The battery pack according to claim 1, wherein, The emergency venting system (10) is housed within the interior space (V) and adjacent to the one or more batteries (4).

3. The battery pack according to claim 2, wherein, The emergency exhaust system (10) is arranged above the one or more batteries (4) along a vertical axis (C) that is perpendicular to the longitudinal axis (A) and the transverse axis (B).

4. The battery pack according to claim 1 or 2, wherein, The emergency venting system (10) is located at a certain distance from the one or more batteries (4).

5. The battery pack according to any one of the preceding claims, wherein, The outlet portion (14) is defined by a pair of vertical walls (14a', 14a'') and a pair of transverse walls (14b', 14b''), the pair of vertical walls (14a', 14a'') facing each other along the vertical axis (C) and each connected to a corresponding one of the upper main wall (16a) and the lower main wall (16b), and the pair of transverse walls (14b', 14b'') facing each other along the longitudinal axis (A) and each connected to a corresponding one of the vertical walls (14a', 14a'').

6. The battery pack according to claim 5, wherein, The transverse walls (14b', 14b'') define an opening (15) configured to accommodate the exhaust valve (3).

7. The battery pack according to claim 6, wherein, The opening (15) is arranged vertically along the vertical axis (C) and is lower than the lower main wall (16b).

8. The battery pack according to any one of the preceding claims, wherein, The emergency exhaust system (10) includes a deflector device (17) housed in the exhaust space (E) and carried by at least one of the cover (11) and the base (12), and the deflector device (17) is configured to change the direction of gas flow from the inlet portion (13) toward the outlet portion (14) along at least one of the longitudinal axis (A), the transverse axis (B) and the vertical axis (C).

9. The battery pack according to claim 8, wherein, The baffle device (17) includes a baffle (18) extending along the transverse axis (B).

10. The battery pack according to claim 9 when claim 6 is referenced, wherein, The baffle (18) extends over at least a portion of the extensions of the upper main wall (16a) and the lower main wall (16b).

11. The battery pack according to any one of claims 8 or 9, wherein, The baffle (17) includes a grille portion (19).

12. The battery pack according to claim 11, wherein, The grid portion (19) has a grid-like opening or an opening arranged parallel to one of the longitudinal axis (A), the transverse axis (B), or the vertical axis (C).

13. The battery pack according to any one of claims 9 to 12, wherein, The baffles (17) are arranged laterally and alternately with each other along the direction of the longitudinal axis (A).

14. The battery pack according to any one of the preceding claims, wherein, One of the upper main wall (16a) and the lower main wall (16b) defines a lower portion (16d) along the vertical axis (C).

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

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