Battery pack and matching vehicle

Abstract

Battery assembly and corresponding vehicle The present invention relates to a battery assembly (10), comprising a battery housing (12) and a safety vent (16). The safety vent comprises a connection end piece (30) and a safety means (34). The safety means has a blocking state, in which the safety means fluidly separates an interior space of the battery housing from the connection end piece, and a connecting state. The safety means changes from the blocking state to the connecting state when a determined pressure difference between the interior space of the battery housing (12) and the connection end piece (30) is exceeded. The safety vent comprises pressure equalization means (40) fluidly connecting the interior space of the battery housing and the connection end piece when the safety means is in the blocking state. Figure for abstract: Figure 1

Description

Title of the invention: Battery assembly and corresponding vehicle

[0001] The present invention relates to a battery assembly, of the type comprising a battery casing adapted to contain at least one battery cell, and a safety vent adapted to vent gas from the battery casing, the safety vent comprising a connection end piece, a safety vent body connected to the connection end piece, and a safety means, the safety means having a blocking state in which the safety means fluidly separates an interior space of the battery casing from the connection end piece, and a connecting state in which the safety means fluidly connects the interior space of the battery casing and the connection end piece, and the safety means being adapted to selectively switch from the blocking state to the connecting state upon exceeding a determined pressure difference between the interior space of the battery casing and the connection end piece.

[0002] Battery assemblies are known comprising a battery housing containing a battery cell and a rupture membrane assembly adapted to vent gas from the battery housing. Such an assembly is known from WO2022029380A1 (corresponding to EP4014277).

[0003] The rupture membrane assembly comprises a membrane retainer, a rupture membrane and a fixing flange. The rupture membrane is adapted to rupture when a pressure difference between the two sides of the membrane exceeds a threshold pressure difference.

[0004] A battery assembly is also known from WO2014131063A2 (corresponding to EP2959522). In this document, the membrane retaining element and a fixing flange comprise pressure equalizing openings that connect the battery housing to an environment surrounding the battery housing.

[0005] Other battery assemblies are known from WO2013072468A2 (corresponding to EP2780962) and WO2014131875A1 (corresponding to EP2962340).

[0006] The aim of the invention is to propose a battery assembly which has significant reliability while being economical.

[0007] To this end, the invention relates to a battery assembly as indicated above, characterized in that the safety vent comprises pressure balancing means fluidly connecting the interior space of the battery casing and the connection end piece when the safety means is in the blocking state.

[0008] According to particular embodiments of the battery assembly, the latter may comprise one or more of the following characteristics:

[0009] - the safety means comprises a shutter element and in which the means pressure balancing includes a pressure balancing opening;

[0010] - the shutter element comprises a rupture disc or a rupture membrane, adapted to break under the effect of a determined difference in pressure between the interior space of the battery housing and the connection end;

[0011] - the safety means comprises a valve, in particular a non-return valve, in wherein the valve is provided with a valve body and a valve closure member, and wherein the closure member is the valve closure member;

[0012] - the pressure balancing opening is provided in the shutter element;

[0013] - the safety means is arranged in the safety vent body, and the opening pressure balancing includes a bypass channel provided in the safety vent body;

[0014] - the pressure balancing opening comprises one or more openings between the shutter element and the safety vent body; and

[0015] - the battery assembly includes a gas discharge pipe connected to the end of connection and the gas exhaust pipe is connected to a gas exhaust port.

[0016] The invention also relates to a vehicle, comprising an outer wall delimiting an interior of the vehicle and an exterior of the vehicle, the vehicle further comprising a battery assembly arranged inside the vehicle, characterized in that the battery assembly is a battery assembly as defined above and in that the connection end piece is connected to the outer wall of the vehicle for the purpose of evacuating the gas to the exterior of the vehicle.

[0017] The invention will be better understood on reading the following description, given solely by way of example and with reference to the appended drawings, in which:

[0018] [Fig-1] [Fig.l] schematically shows a vehicle comprising a set of battery according to a first embodiment of the invention;

[0019] [Fig.2] [Fig.2] schematically shows an enlarged part of the battery assembly according to the first embodiment of the invention, the safety means being in its blocking state;

[0020] [Fig.3] [Fig.3] corresponds to [Fig.2], the safety means being in its connected state;

[0021] [Fig.4] [Fig.4] schematically shows part of a battery assembly according to a second embodiment of the invention;

[0022] [Fig.5] [Fig.5] schematically shows part of a battery assembly according to a third embodiment of the invention; and

[0023] [Fig.6] [Fig.6] schematically shows part of a battery assembly according to a fourth embodiment of the invention.

[0024] In [Fig. 1] a vehicle according to the invention is schematically represented, designated by the general reference 2. The vehicle 2 can be chosen from the list consisting of an aircraft, a means of rail transport, a means of road transport, a means of maritime or river transport. The vehicle 2 comprises an outer wall 4 delimiting an interior of the vehicle IV and an exterior of the vehicle EV. The interior of the vehicle IV forms, for example, a battery compartment.

[0025] The vehicle 2 comprises a battery assembly 10 generally arranged inside the vehicle IV, and preferably inside the battery compartment.

[0026] When it is mounted in a vehicle, the battery assembly 10 is configured to provide electrical power. The electrical power is for example sufficient for the propulsion of the vehicle, via an electric or hybrid motor (not shown). Alternatively or in addition, the electrical power is used to power the navigation instruments and / or to power the comfort elements mounted in the vehicle.

[0027] According to the embodiments shown, the battery assembly 10 is arranged in the vehicle 2. Alternatively, according to embodiments not shown, the battery assembly is arranged in an electrical storage bay, for example formed by a stationary container.

[0028] The battery assembly 10 is advantageously arranged in a dedicated space.

[0029] The battery assembly 10 includes a battery housing 12 adapted to contain at least minus one 14 battery cell.

[0030] In this instance, the battery assembly 10 comprises two battery cells 14. The battery assembly 10 may comprise more than two of these battery cells 14.

[0031] Each battery cell 14 or electrochemical element is for example a battery cell of the Lithium-Ion type.

[0032] In the present embodiment, two battery cells 14 are housed in the battery housing 12. Alternatively, the battery housing 12 houses more than two battery cells 14, for example four battery cells 14. As a further alternative, the battery housing 12 houses a single battery cell 14.

[0033] The battery casing 12 is adapted to contain the flames and gases generated in the event of thermal runaway of a battery cell 14. The battery casing 12 is for example made of aluminum.

[0034] The battery assembly 10 is provided with a safety vent 16 adapted to evacuate gas from the battery housing 12. In the event of thermal runaway of one or more battery cells 14, the safety vent 16 evacuates the generated gases from the battery housing 12.

[0035] The battery casing 12 comprises a casing wall 18, which is an outer wall of this battery casing, and which is provided with a through opening 20 in which the safety vent 16 is arranged (see [Fig.2]).

[0036] Referring again to [Fig.l], the battery assembly 10 includes a gas vent pipe 22 connected to the safety vent 16, for venting from the battery housing 12 the gases generated during a failure of the battery cell(s) 14.

[0037] The vehicle 2 also comprises a gas discharge port 24 disposed in the outer wall 4. The gas discharge pipe 22 is connected to this gas discharge port 24 in order to convey the gases generated during a failure of the battery cells 14, through the gas discharge pipe 22, out of the vehicle.

[0038] The gas pipe 22 is advantageously gas-tight over its entire length and therefore comprises as only inlet and outlet locations the safety vent 16 and the gas discharge port 24. Thus, pollution of the interior of the vehicle IV or the battery compartment with gases from the battery is avoided. Furthermore, pollution of the interior of the battery casing with moisture or other pollutants from the interior of the vehicle IV or the battery compartment surrounding the battery casing is avoided.

[0039] [Fig. 2] shows a portion of the battery assembly 10 of [Fig. 1] on an enlarged scale and in cross-section. More specifically, [Fig. 2] shows a portion of the housing wall 18 and the safety vent 16. The outer wall 4, the gas vent pipe 22 and the gas vent port 24 are only shown schematically in broken lines.

[0040] The safety vent 16 comprises a connection end piece 30, in this case tubular, a safety vent body 32, fixed to the connection end piece 30, and a safety means 34. The safety vent 16 also comprises a fixing member 36, for example a nut.

[0041] The connection end piece 30 and / or the safety vent body 32 is / are for example made of metal. In this case, the connection end piece 30 and the safety vent body 32 are in one piece, preferably in one piece.

[0042] The safety vent body 32 extends through the through opening 20. The safety vent body 32 is fixed by the fixing member 36 to the housing wall 18. The safety vent body 32 is connected to the housing wall 18 in a gas-tight manner, for example by a seal, not shown.

[0043] The safety vent body 32 is also provided with a fixing flange 38 which extends on the side of the casing wall 18 opposite the fixing member 36.

[0044] The safety means 34 has a blocking state in which the safety means 34 fluidly separates the interior space of the battery casing 12 from the end piece connection 30, and a connection state in which the safety means 34 fluidly connects the interior space of the battery housing 12 and the connection tip 30.

[0045] The tubular connection end piece 30 is connected to the outer wall 4 of the vehicle for the purpose of evacuating the gas to the outside of the vehicle, in this case via the evacuation pipe 22.

[0046] In [Fig. 2], the safety means 34 is shown in its blocked state. In this blocked state, gases from the battery cells 14 are prevented by the safety means 34 from flowing into the connection end piece 30 and therefore towards the gas discharge pipe 22.

[0047] The safety means 34 is adapted to selectively switch from the blocking state to the connection state when a determined pressure difference AP=Pcarter-Ptuyau is exceeded between the interior space of the battery casing 12 and the connection end piece 30, more precisely the interior of this connection end piece 30. The safety means 34 is thus adapted to yield when a pressure difference equal to or greater than the determined pressure difference AP.

[0048] The determined pressure difference AP is for example between 1.5 bar and 3 bar.

[0049] The safety vent 16 further comprises pressure balancing means 40 fluidly connecting the interior space of the battery casing 12 and the connection end piece 30 when the safety means 34 is in the blocked state, and particularly permanently.

[0050] The pressure balancing means 40 have, for a given pressure difference between the interior space of the battery housing 12 and the connection end piece 30, a gas flow rate lower than the gas flow rate of the safety means 34 in the connected state. The pressure balancing means 40 fluidly connect the interior space of the battery housing 12 and the connection end piece 30 in such a way that a pressure difference between the interior space of the battery housing 12 and the interior of the connection end piece 30 is equalized in a few seconds, for example in less than 2 seconds.

[0051] The pressure balancing means 40 are adapted to allow the establishment of the determined pressure difference during a failure of a battery cell 14. Thus, the pressure balancing means 40 fluidly connect the interior space of the battery casing 12 and the connection end piece 30 in such a way that, when the determined pressure difference AP is established or exceeded, this pressure difference is equalized in a time greater than the time necessary to trigger the passage of the safety means 34 from the blocking state to the connection state.

[0052] For example, for a given pressure difference, the gas flow rate of the pressure balancing means 40 is less than 1 / 10 of the gas flow rate of the safety means 34 in the connected state.

[0053] The pressure balancing means 40 comprise, for example, a pressure balancing opening 42. The pressure balancing opening 42 comprises in this case a bypass channel 44 formed in the safety vent body 32. The bypass channel 44 is in this case bent, but it can also be straight over its entire extent.

[0054] In this case, the safety means 34 comprises a closure element 46. This closure element 46 comprises or consists of a rupture disk or a rupture membrane 48 which is adapted to rupture under the effect of a determined difference in pressure between the interior space of the battery casing and the connection end piece. The rupture disk or the rupture membrane 48 are for example made of a metal or a metal alloy. The closure element 46 is fixed to the safety vent body 32, for example by gluing or welding or by complementary shapes. As an exemplary embodiment, the rupture disk 48 may comprise the characteristics of the disk 400 disclosed in document US9412985B2, column 7, lines 34 and following, and having one or more thinned zone(s).

[0055] In this case, the safety means 34 is arranged in the safety vent body 32.

[0056] [Fig. 3] corresponds to [Fig. 2] and shows the safety means 34 in its connected state. In its connected state, the safety means 34 allows gases from the battery cells 14 to flow freely through the connection tip 30 and to the gas discharge pipe 22.

[0057] As can be seen, the rupture disc 48 is in the ruptured state and therefore establishes a fluid connection allowing gases from the battery cells 14 to circulate freely in the connection end piece 30 and therefore towards and into the interior of the gas evacuation pipe 22.

[0058] Referring again to [Fig. 1], the battery casing 12 is in this case provided with a breathing port 60, which connects the interior of the battery casing 12 to the interior of the vehicle IV. The function of the breathing port 60 is to balance the pressures between the interior of the battery casing and the environment around the battery casing, i.e. the interior of the vehicle IV. This makes it possible to reduce the mechanical stresses acting on the battery casing 12 and on the safety means 34, in particular on the rupture disc or on the rupture membrane 48. This breathing port 60 is however optional.

[0059] The battery assembly operates as follows.

[0060] All battery cells 14 are in the normal operating state. The safety means 34 is in the blocking state.

[0061] When a gas pressure difference is established between the gas discharge pipe 22 and the inside of the battery casing 12, this pressure difference being lower than the determined pressure difference, the pressure balancing means 40 lead to the equalization of the pressure between the interior of the battery housing 12 and the gas discharge pipe 22. Thus the gas pressure upstream and downstream of the safety means 34 is equalized and the safety means 34 is only subjected to low mechanical stresses.

[0062] When one of the battery cells 14 fails, for example during thermal runaway, gas is generated, which causes the gas pressure inside the battery casing 12 to increase rapidly since the pressure balancing means 40 only allow a very low flow rate.

[0063] When the pressure difference between the inside of the battery housing 12 and the inside of the gas discharge pipe 22 reaches or exceeds the determined pressure difference AP, the safety means 34 yields and passes from the blocking state to the connecting state. In this case, the transition from the blocking state to the connecting state is the rupture of the rupture disc or the rupture membrane 48.

[0064] Thus, the gases generated by the failure of the battery cells 14 are evacuated from the battery casing 12.

[0065] Once the gas pressure in the exhaust pipe 22 is high enough, the gas exhaust port 24 opens and the gases are exhausted from the vehicle 2.

[0066] [Fig.4] shows a second embodiment of the invention. [Fig.4] corresponds to [Fig.2]. Only the differences from the first embodiment will be described. Similar elements have the same references.

[0067] The pressure balancing opening 42 is not provided in the safety vent body 32, but in the closure element 46, in particular in the rupture disc or in the rupture membrane. The safety vent body 32 is therefore without a pressure balancing opening 42.

[0068] In this case, the pressure balancing opening 42 is a through-orifice 44, and not a bypass channel. The dimensions of the through-orifice 44 are chosen such that the function of the through-orifice 44 is identical to the function of the bypass channel of the first embodiment.

[0069] In this case, a through orifice 44 is provided in the center of the shutter element 46.

[0070] In [Fig.5] is shown schematically a part of a battery assembly according to a third embodiment of the invention. The view corresponds to the view of [Fig. 2], the outer wall 4, the gas discharge pipe 22 and the gas discharge port 24 being omitted. Only the differences from the first embodiment will be described. Similar elements bear the same references.

[0071] The pressure balancing opening 40 comprises one or more pressure balancing openings 42 which are in this case one or more openings through(s) formed between the shutter element 46 and the safety vent body 32.

[0072] The shutter element 46 is attached to the safety vent body 32 by a material connection, such as by welding, brazing or gluing.

[0073] In the present case, this / these through opening(s) is / are formed by one or more locations in the absence of sealing. In this case, each through opening is formed by a gap between material connection points fixing the shutter element 46 to the safety vent body 32.

[0074] [Fig. 6] schematically represents a part of a battery assembly according to a fourth embodiment of the invention. [Fig. 6] corresponds to [Fig. 2], the outer wall 4, the gas discharge pipe 22 and the gas discharge port 24 being omitted. Only the differences from the first embodiment will be described. Similar elements bear the same references.

[0075] According to this fourth embodiment, the safety means 34 comprises a valve 70, in particular a non-return valve. The valve 70 is provided with a valve body 72, which forms the safety vent body 32, and a valve shutter element 74, which forms the shutter element 46. The valve shutter element 74 is shown in solid lines in its position corresponding to the blocking state and in broken lines in its position corresponding to the connection state.

[0076] In the case shown, each pressure balancing opening 42 is formed by a recess arranged between the valve body 72 and the valve closing element 74 and remaining in the closed state of the valve 70. More precisely, each pressure balancing opening 42 is formed by a groove provided in the valve body 72.

[0077] Alternatively or additionally (not shown), the pressure balancing opening is provided in the valve closure element 74 and is for example a conduit passing through the valve closure element 74.

[0078] In a variant not shown, the vehicle 2 comprises a first battery assembly, which is the aforementioned battery assembly 10, and an additional battery assembly, which also comprises the features of the aforementioned battery assembly 10. In this case, the gas discharge pipe 22 of each of the battery assemblies 10 is connected to a gas discharge collector pipe which is in turn connected to the gas discharge port 24.

[0079] As a further variant, the invention does not relate to a vehicle, but to a stationary storage bay. In this case, the vehicle 2 is replaced by a stationary storage bay. This stationary storage bay comprises an outer wall, which corresponds to the outer wall 4. The outer wall delimits a storage bay interior, which corresponds to the interior of the vehicle IV, and a storage bay exterior storage, which corresponds to the exterior of the EV vehicle. The storage bay includes a battery assembly that is identical to the battery assembly 10 described above in connection with the vehicle 2.

[0080] Such a battery assembly is intended to be used within an electrical power storage system, in particular when the storage system is on board a vehicle such as an aircraft, a rail transport vehicle, a road transport vehicle or a maritime or river transport vehicle. Alternatively, the battery assembly is intended for the static storage of electrical energy, for example in the form of at least one electrical storage bay in which several battery modules are stacked.

[0081] The present invention therefore generally proposes to provide a static pressure balancing device on the safety vent or on the safety valve device, between the battery and the gas evacuation system, in order to balance the pressure of the gas evacuation pipe with the battery.

[0082] The static pressure balancing device must obviously not allow gas flows contrary to the hermeticity function but is just sufficient to balance the pressure in the medium term.

[0083] The arrangement of the pressure balancing openings at the locations disclosed in the present description provides, as the case may be, among other things, the following advantages: no need for openings in the battery housing, no need to provide aligned orifices in different components, no need to provide openings in the gas discharge pipe.

[0084] Furthermore, the assembly according to the invention makes it possible to limit the pressure difference between the upstream and downstream of the shutter element. The arrangement described also makes it possible to make the triggering of the rupture disc or rupture membrane more reliable and to have it triggered at a relatively low pressure difference. The invention makes it possible to eliminate or omit a pressure balancing device at the outlet of the evacuation pipe. The assembly according to the invention makes it possible to balance the pressures without risk of contaminating the battery room in the event of evacuation.

[0085] The assembly according to the invention is therefore economical to manufacture and leads to significant reliability.

[0086] The foregoing description contains technical features of the invention. These technical features, although presented in a technical context and possibly in combination with other technical features, can be used individually each time, without the other technical features, as far as this is technically possible.

Claims

Claims

1. Battery assembly (10), of the type comprising a battery housing (12) adapted to contain at least one battery cell (14), and a safety vent (16) adapted to vent gas from the battery housing, the safety vent comprising a connection end piece (30), a safety vent body (32) connected to the connection end piece, and a safety means (34), the safety means having a blocking state in which the safety means fluidly separates an interior space of the battery housing from the connection end piece, and a connecting state in which the safety means fluidly connects the interior space of the battery housing and the connection end piece, and the safety means being adapted to selectively switch from the blocking state to the connecting state upon exceeding a determined pressure difference (AP) between the interior space of the battery housing (12) and the connection end piece (30),characterized in that the safety vent comprises pressure balancing means (40) fluidly connecting the interior space of the battery housing and the connection tip when the safety means is in the blocking state.,

2. A battery assembly according to claim 1, wherein the safety means (34) comprises a shutter member (46) and wherein the pressure equalization means comprises a pressure equalization opening (42).

3. Battery assembly according to claim 2, in which the closure element (46) comprises a rupture disc or a rupture membrane (48), adapted to rupture under the effect of a determined difference in pressure between the interior space of the battery casing and the connection end piece.

4. A battery assembly according to claim 2 or 3, wherein the safety means (34) comprises a valve (70), in particular a non-return valve, wherein the valve is provided with a valve body (72) and a valve shutter element (74), and wherein the shutter element (46) is the valve shutter element (74).

5. A battery assembly according to any one of claims 2 to 4, wherein the pressure equalization opening is provided in the closure member.

6. A battery assembly according to any one of claims 2 to 5, wherein the safety means (34) is disposed in the safety vent body (32), and wherein the pressure equalization opening comprises a bypass channel (44) provided in the safety vent body (32).

7. A battery assembly according to any one of claims 2 to 6, wherein the pressure equalization opening comprises one or more openings between the shutter member (46) and the safety vent body (32).

8. A battery assembly according to any one of claims 1 to 7, wherein the battery assembly comprises a gas discharge pipe (22) connected to the connection tip and wherein the gas discharge pipe (22) is connected to a gas discharge port (24).

9. Vehicle (2), in particular aircraft, of the type comprising an outer wall (4) delimiting an interior of the vehicle and an exterior of the vehicle, the vehicle further comprising a battery assembly arranged inside the vehicle, characterized in that the battery assembly is a battery assembly (10) according to any one of claims 1 to 8 and in that the connection end piece (30) is connected to the outer wall of the vehicle for the purpose of evacuating the gas to the exterior of the vehicle.

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