Housing provided with a vent valve

Abstract

The invention relates to a housing (110) comprising: - a bottom wall (120), a cover wall (130) and a hollow side wall (140) that extends between the bottom wall and the cover wall and defines an inner cavity (111), the hollow side wall being delimited by an outer partition wall (141) and an inner partition wall (142), the inner cavity being configured to receive at least one energy storage device (150); - a vent valve (160) for venting gases from the at least one energy storage device, the vent valve being arranged in the outer partition wall of the hollow side wall; - an internal hollow wall (170) arranged in the inner cavity, the internal hollow wall being delimited by two internal partition walls (171, 172) and comprising an end (173) opening into the hollow wall (140), the internal hollow wall (170) having at least one internal opening (175) in at least one of the two internal partition walls (171, 172), the hollow walls (140, 170) defining a channel (146) for cooling the gases from the at least one internal opening to the vent valve.

Description

[0001] DESCRIPTION

[0002] Title of the invention: Housing equipped with a drain valve

[0003] The present invention relates to the field of batteries, particularly those used in electric or hybrid vehicles operating in electric mode. More specifically, the invention concerns a housing equipped with a drain valve and a battery comprising such a housing.

[0004] In an electric or hybrid vehicle, the electric motor system is powered by a high-voltage battery that propels the vehicle. More generally, the battery provides the energy needed to operate a motor or other electrical components.

[0005] As is well known, in a battery (for example, lithium-ion or sodium-ion), several electrochemical cells are electrically connected in series, parallel, or a combination of series and parallel. An electrochemical cell is a cell that produces electrical energy based on chemical reactions that release energy. It is also referred to as an energy storage device, specifically a battery cell. The energy storage devices of a battery are housed within a battery casing. The battery can be located under the vehicle it powers. Therefore, the casing is sealed to ensure the integrity of the battery's components.

[0006] Energy storage technologies for electric vehicle batteries are constantly evolving. This evolution leads to the storage of increasingly larger quantities of energy in increasingly smaller volumes, both for reasons of energy supply and to minimize size.

[0007] During battery use, and for various reasons such as a manufacturing defect, a temporary overcharge, or a short circuit caused by a contaminant within an energy storage component, thermal runaway (also known as "thermal runaway") can occur. This thermal runaway follows a series of steps: a hot spot develops within an energy storage component, and then the component begins to burn. The surrounding air heats up. Flammable gases accumulate inside the battery casing. This accumulation contributes to the increase in pressure and temperature within the casing. It is this thermal runaway that can lead to the sudden ignition of the battery.

[0008] Since thermal runaway cannot be stopped, or only with great difficulty, it is necessary to implement safety measures to delay the onset of a general fire, giving vehicle occupants time to move away and emergency services time to intervene. For example, current regulations mandate a minimum of five minutes between the detection of a fire originating from the battery and the appearance of a flame.

[0009] As mentioned above, thermal runaway is initiated under conditions of high pressure and temperature. In other words, when thermal runaway occurs, it is always accompanied by very hot air present in the battery casing. This very hot air can reach temperatures of several hundred degrees Celsius, for example, 700°C. The temperature increase creates overpressure within the casing.

[0010] A well-known preventative measure is to install a safety valve on the battery casing. This safety valve, or vent valve, allows the release of gases from the energy storage components. Therefore, in the event of a battery malfunction, the vent valve releases hot air to counteract the overpressure within the battery casing.

[0011] Such a relief valve is positioned opposite the energy storage components; that is, the relief valve is directly exposed to the energy storage components in order to release the gas flow to be discharged. However, this type of valve is usually made of plastic. And because the relief valve is positioned opposite the heat source constituted by the energy storage component, it deteriorates rapidly as soon as the temperature of the gas flow to be discharged reaches a certain point.

[0012] Furthermore, for reasons of space and cost, it is preferable to have a small number of vent valves per battery. To ensure the venting of a given gas flow rate, a large passage cross-section for the vent valve is therefore required, for example, on the order of 50 cm². 2This constraint raises the issue of electromagnetic wave protection. Indeed, for safety reasons, the battery's voltage and temperature are monitored throughout its lifespan. As an illustrative example, each energy storage component can be voltage-monitored, and one in ten can be temperature-monitored. This monitoring ensures the battery's proper functioning or, conversely, detects any potential malfunctions. Given the large number of energy storage components to monitor, using wired connections to transmit the data from this monitoring would be too complex.Modern batteries are equipped with a BMS (Battery Management System), an electronic component that provides continuous monitoring and control of the entire battery, particularly its energy storage components. Batteries also include a wireless module that transmits data from the battery to a remote data processing center. For data security reasons, it is essential that the signals transmitted from the wireless module are not intercepted by third parties. Similarly, it is crucial to prevent unauthorized access to the BMS. In other words, the battery must be protected against electromagnetic interference.

[0013] It follows from this that the solutions for evacuating gases from the prior art are not entirely satisfactory.

[0014] The present invention falls within this context and aims to provide a battery housing equipped with a vent valve located away from the heat source via a gas vent channel. This solution cools the gases to be vented before they come into contact with the vent valve, thus preserving its integrity. A specific configuration of the vent channel also ensures complete protection of the battery against electromagnetic waves.

[0015] To this end, the invention relates to a housing, particularly for a motor vehicle battery, comprising: a base wall, a lid wall and a hollow side wall extending between the base wall and the lid wall defining an internal compartment, the hollow side wall being delimited by an outer partition and an inner partition, the internal compartment being configured to accommodate at least one energy storage element, in particular a battery cell, a gas vent valve from at least one energy storage element, the vent valve being disposed in the outer partition of the hollow side wall, the housing being characterized in that it further comprises at least one internal hollow wall disposed in the internal compartment, in particular forming a stiffening element of the housing and / or a separation element of the internal compartment,the internal hollow wall being delimited by two internal partitions and comprising an end opening into the hollow wall, and in that the internal hollow wall has at least one internal opening in at least one of the two internal partitions, the hollow walls defining a gas cooling channel from the at least one internal opening to the discharge valve, so as to fluidly connect the inner housing to the discharge valve.

[0016] Thanks to these features, the housing allows for the integration of a hot gas exhaust circuit within the battery casing's double-walled structure. This exhaust circuit acts as a cooling channel for the exhaust gases. The cooling channel runs from the inner chamber of the housing to the outlet at a vent valve. Extending within the hollow walls of the housing, the cooling channel can be considered as comprising three parts: the first part receives the hot gases (the openings), the second part contributes to cooling the hot gases (upon contact with the outer walls of the housing), and the third part expels the cooled gases from the housing (the vent valve).

[0017] As a result, the exhaust valve is never directly exposed to an airflow coming directly from the internal housing of the case. Before reaching the exhaust valve, the gases to be exhausted have had time to cool down in the cooling channel.

[0018] It is understood here that the gas evacuation channel and the gas evacuation valve are configured to evacuate a fluid of the gas type mainly, but also a liquid or a mixture of gas and liquid.

[0019] According to an optional feature of the invention, the hollow side wall has at least one internal opening in the inner partition. The housing thus has a plurality of openings at different locations within the internal structure. The hot gases to be exhausted are collected through multiple openings in the hollow walls, where the gases are cooled before exiting through the exhaust valve. The plurality of openings in the hollow walls of the housing allows for the exhaust of a certain flow rate of hot gases.

[0020] According to an optional feature of the invention, at least one of the at least one internal opening and the at least one internal opening is disposed at a distance from the lid wall such that said at least one opening is closer to the lid wall than to the bottom wall, said distance being preferably less than or equal to one third of the distance between the lid wall and the bottom wall.

[0021] By positioning the opening(s) as high as possible in the hollow walls, the mass of hot air inside the case is reduced. Since hot gases rise to the top of the case, this positioning of the openings ensures easier gas evacuation.

[0022] According to an optional feature of the invention, at least one of the side hollow wall and the internal hollow wall having at least one opening further comprises an intermediate partition partially dividing said hollow wall into: an upper zone disposed above the intermediate partition and into which at least one opening of said hollow wall opens, and a lower zone disposed below the intermediate partition, the intermediate partition comprising a passage between the upper zone and the lower zone of said hollow wall, the cooling channel extending through the lower zone, from at least one opening of the upper zone to the drain valve.

[0023] To reach the exhaust valve, the cooling channel can be longer, resulting in a larger cooling area. The exhaust gases thus travel back and forth within the same wall, entering through the opening in the upper zone and then flowing towards the lower zone of that same wall.

[0024] According to an optional feature of the invention, the housing includes an electromagnetic shielding device disposed in the cooling channel.

[0025] The shielding device can be a simple grille placed over the openings. According to an optional feature of the invention, the shielding device covers at least one of the openings in the inner or internal partition.

[0026] According to an optional feature of the invention, the shielding device comprises a plurality of orifices of predefined dimensions. For example, the shielding device may be a grid made of holes with a diameter of 3 mm and a pitch of approximately 9 mm, arranged perpendicular to the gas flow to isolate the battery casing from electromagnetic waves.

[0027] According to an optional feature of the invention, the shielding device is a metal grid extending perpendicularly to one of the partitions forming the cooling channel.

[0028] In addition to preventing the transmission of electromagnetic waves, the shielding device filters out any particles from the fire that may originate from the interior dwelling.

[0029] The invention also covers a battery comprising at least one energy storage element, in particular a battery cell, and such a casing, said storage element being disposed in the internal housing of the casing.

[0030] Other features and advantages of the invention will become apparent from the following description on the one hand, and from several illustrative and non-limiting examples of embodiments given with reference to the attached schematic drawings on the other hand, in which:

[0031] [Fig. 1] represents a semi-open view of a battery according to the invention,

[0032] [fig 2] represents a cross-sectional view of the housing of the invention along a transverse plane of the housing,

[0033] [fig 3] represents a cross-sectional view of two variants of the battery housing of the invention according to section AA of figure 2,

[0034] [fig 4] represents a cross-sectional view of two variants of the battery casing of the invention according to section BB of figure 4,

[0035] [fig 5] represents a cross-sectional view of another variant of the battery housing of the invention according to section CC, [fig 6] represents a portion of the battery housing of the invention with a shielding device.

[0036] The features, variations, and different embodiments of the invention, as described or as they will be presented in the detailed description that follows, can be combined in various ways, provided they are not incompatible or mutually exclusive. In particular, variations of the invention may be conceived comprising only a selection of features, described hereafter in isolation from the other described features, if this selection of features is sufficient to confer a technical advantage and / or to differentiate the invention from the prior art.

[0037] For the sake of clarity, the same elements are designated by the same references in the different figures.

[0038] Figure 1 shows a semi-open view of a battery 100 according to the invention. The battery 100 comprises at least one energy storage element, in particular a battery cell, and a casing 110. The storage element(s) are arranged in an internal housing 111 of the casing 110.

[0039] The invention also relates to the casing 110, particularly for an automotive battery. The casing 110 comprises a base wall 120, a lid wall 130, and a hollow side wall 140. The hollow side wall 140 extends between the base wall 120 and the lid wall 130. The hollow wall 140 extends around the perimeter of the casing 110. The base and lid walls and the hollow side wall define an internal compartment 111 of the casing. The internal compartment 111 accommodates at least one energy storage element 150, in particular a battery cell.

[0040] The hollow side wall 140 is delimited by an outer partition 141 and an inner partition 142. It is understood that the side wall 140 is not solid. In other words, the side wall 140 is at least partially hollow: the outer partition 141 is spaced apart from the inner partition 142.

[0041] The housing 110 also includes a vent valve 160 for gases emanating from at least one energy storage unit 150. The vent valve is located in the outer partition 141 of the side cavity wall. It can be positioned along the length of the housing or along its width. Such a valve, known in the prior art, moves from a closed to an open position to release gas when subjected to overpressure. It ensures the venting of hot gases as soon as they are produced and generate overpressure in the housing.

[0042] According to the invention, the housing 110 further comprises at least one internal hollow wall 170 disposed within the internal cavity 111, notably forming a stiffening element for the housing and / or a partition for the internal cavity. The internal hollow wall(s) can thus form sub-volumes within the internal cavity. These sub-volumes are preferably sealed and can be intended to house one or more energy storage components. Similar to the lateral hollow wall 140, the internal hollow wall 170 is delimited by two internal partitions 171, 172. In other words, the two internal partitions 171, 172 are spaced apart so that the internal wall 170 is not solid. The wall 170 includes an end 173 opening into the hollow wall 140. It is therefore understood that the internal space of the internal hollow wall 170 is fluidly connected to the internal space of the lateral hollow wall.In the housing of the invention, the internal hollow wall 170 has at least one internal opening 175 in at least one of the two internal partitions 171, 172. Thus, the hollow walls 140, 170 define a gas cooling channel 146 from the at least one internal opening 175 to the discharge valve 160, so as to fluidly connect the internal housing 111 to the discharge valve 160.

[0043] Hollow walls, whether side or internal, provide structural rigidity to the casing. They help absorb shock energy to prevent deformation of the energy storage components within the casing.

[0044] At the initiation of thermal packaging, hot gases are generated in the internal compartment 111 of the casing 110. They create overpressure within the casing. The combined conditions of high pressure and high temperature are conducive to the development of thermal packaging. To mitigate the propagation of thermal packaging, the hot gases must be vented. As explained previously, these hot gases must be cooled before reaching the vent valve to prevent damage. The casing of the invention utilizes the volume within the hollow walls to form a cooling channel for the gases to be vented. The gases to be vented pass through this cooling channel. During their transit through this channel, heat exchange occurs with the casing walls, which are generally made of aluminum.The housing structure is heated by the exhaust gases, which gradually cool as they travel through the cooling channel until they reach the exhaust valve. It should be noted that the exhaust gases retain some thermal energy, which generates an overpressure that triggers the opening of the exhaust valve.

[0045] The cooling channel formed within the hollow walls, extending from an internal opening 175 in an internal hollow wall 170 located in the internal housing 111 to the exhaust valve, provides the exhaust gases with the longest possible path to allow them to cool. Thus, the exhaust gases are channeled through the hollow walls. The internal opening 175 serves as the entry point for hot gases into the cooling channel 146, and the valve 160 serves as the exit point for the cooled gases along the cooling channel. The exhaust valve 160 is therefore not directly exposed to the hot gases. The construction of the cooling channel 146 from the internal and lateral hollow walls 170, 140 is particularly advantageous. The internal opening 175 allows direct access of hot gases from the internal housing 111 to the cooling channel 146.The cooling channel 146 extends at least partially through the internal housing 111 of the casing 110. A path for the hot gases is formed without the addition of any extra elements. The invention utilizes hollow walls. Thanks to the cooling channel in the hollow walls, the gases to be exhausted have the opportunity to release some of their thermal energy before coming into contact with the exhaust valve 160.

[0046] Figure 2 shows a cross-sectional view of the housing of the invention along a transverse plane of the housing. In this view, the internal hollow wall 170 extends through the internal cavity 111 across the entire width of the housing. However, the invention remains within the scope of the invention even if the internal hollow wall 170 extends only partially inside the housing. The internal opening 175 is located in the internal partition 171, at the center of the housing 110. This is a non-limiting example. The invention also covers the case of an internal opening 175 located at another point on the internal partition 171, or of several internal openings 175 along the internal hollow wall 170. The internal opening 175 (or openings) may also be located on the internal partition 172.The invention also applies to the case of a plurality of internal hollow walls 170, at least one of the plurality of internal hollow walls having at least one internal opening 175, on one or both of its partition(s).

[0047] Figure 2 illustrates, with a shaded area, the path of the gases to be evacuated in the cooling channel 146 through the internal hollow wall 170 and the lateral hollow wall 140. The hot gases initially in the inner housing 111 pass through the internal opening 175. At this point, the pressure in the internal housing 111 of the casing 110 is higher than the pressure outside the casing 110. Due to this pressure differential, the hot gases are directed into the cooling channel 146 to reach the evacuation valve 160. The hot gases first pass through the internal hollow wall 170, then join the lateral hollow wall 140 via the end 173 of the internal hollow wall 170, and finally pass through the lateral hollow wall 140 to the evacuation valve.The length of the cooling channel 146 between the opening 175 and the exhaust valve 160 ensures a sufficiently long transport time for the exhaust gases to allow them to lose heat through the outer partition 141 of the lateral hollow wall 140. The hot gas collection point at the level of the inner hollow wall 170 offers two advantages: firstly, the exhaust gases must travel through the cooling channel 146 in the inner wall 170 and then in the lateral wall 140 before reaching the exhaust valve, thus promoting gas cooling; and secondly, the inner opening 175 is not directly opposite the exhaust valve 160, preventing any direct contact between the hot gases and the exhaust valve. The cooling channel therefore fulfills the dual role of cooling the hot exhaust gases and protecting the exhaust valve.

[0048] Figure 3 shows a cross-sectional view of two variants of the battery casing 110 of the invention according to section AA of Figure 2. In these two variants, the lateral hollow wall 140 has at least one internal opening 145 in the internal partition 142. This opening 145 is in addition to the internal opening 175 in the internal hollow wall 170. This additional opening 145 allows for a greater flow of hot gases through the cooling channel.

[0049] Every internal opening 145 is associated with an internal partition 142 of the lateral hollow wall 140. In axial projection onto said internal partition 142, the opening 145 and the vent valve 160 are separated by a non-zero distance. In other words, the vent valve 160 is never directly opposite an internal opening 145. Thus, it is ensured that the vent valve is not directly exposed to the hot gases to be vented.

[0050] As shown for the internal opening 145 (but applicable to all openings), the internal opening 145 is positioned at a distance dl from the lid wall 130 such that at least one opening is closer to the lid wall 130 than to the bottom wall 120. The distance dl is preferably less than or equal to one-third of the distance between the lid wall 130 and the bottom wall 120. Since hot air rises, positioning the opening(s) on the upper part of the hollow wall(s) facilitates the passage of hot gases from the internal housing 111 to the cooling channel 146. This reduces the volume of hot gases in the internal housing 111 of the casing 110.

[0051] The variant of the housing 110 shown on the right of Figure 3 is identical to the variant of the housing 110 shown on the left of Figure 3. This variant further includes an intermediate partition 147 partially dividing the hollow wall 140 into an upper zone 148 located above the intermediate partition 147, into which the opening 145 of the hollow wall opens, and a lower zone 149 located below the intermediate partition 147. The cooling channel 146 is divided into two zones 148 and 149. In this configuration, the hot gases enter the cooling channel 146 through the upper zone 148, without necessarily passing through the lower zone 149. The insertion of the intermediate partition in the hollow walls allows the path followed by the gases in the cooling channel 146 to be modulated. An example embodiment will be detailed below based on Figure 5.

[0052] Figure 4 shows a cross-sectional view of two variants of the battery housing of the invention according to section BB of Figure 2, and more specifically the cross-sectional plane which here contains two internal openings 175. On the variant on the left, it is understood that the gases to be evacuated leave the housing through the two openings 175 to enter the internal hollow wall 170. Then, they enter the side wall 140 through the end 173 of the internal wall 170 which opens into the side wall 140. Subsequently, as explained previously, the gases are expelled from the housing by the evacuation valve.

[0053] The variant of the housing 110 shown on the right of Figure 4 is identical to the variant of the housing 110 shown on the left of Figure 4. It further includes an intermediate partition 147, shown above. Figure 5 shows a cross-sectional view of another variant of the battery housing of the invention according to section CC. This is a cross-section of the side wall 140 containing two openings 145. In this configuration, the side wall includes an intermediate partition 147 partially separating the hollow wall 140 into an upper zone 148 and a lower zone 149, as detailed previously. The intermediate partition 147 here includes a passage 1471 between the upper zone 148 and the lower zone 149 of the hollow wall 140. The cooling channel 146 extends through the lower zone 149, from the two openings 145 of the upper zone 148 to the drain valve 160.It is thus understood that hot gases leave the inner compartment 111 through the two openings 145 and arrive in the upper zone 148 of the side wall 140. At the end of the upper zone 148 of the side wall 140, the hot gases reach the lower zone 149 by passing through the passage 1471. At another end of the side wall, particularly positioned in the lower part, the gases to be exhausted reach the exhaust valve 160 directly, or indirectly via another portion of the side wall. The use of an intermediate partition coupled with a passage between the upper and lower zones of the hollow wall allows the cooling channel to be lengthened. As a result, the hot gases have a longer path to travel to the exhaust valve, which optimizes heat exchange with the external walls of the housing.

[0054] Figure 6 shows a portion of the battery casing of the invention with a shielding device. In this embodiment, the casing of the invention includes an electromagnetic shielding device 190 disposed in the cooling channel 146. The electromagnetic shielding device 190 ensures the casing is sealed against electromagnetic waves. It prevents any interception of waves transmitted to or from the casing.

[0055] In one variant, the shielding device 190 covers at least one of the openings 145, 175 in the inner partition 142 or internal partition 171, 172. This may be a grille affixed against said opening. For example, a metal grille 192 extending perpendicularly to one of the partitions 142, 171, 172 forming the cooling channel 146 may be used.

[0056] The shielding device 190 comprises a plurality of orifices 191 of predefined dimensions. For example, the orifices 191 may have a diameter 193 of approximately 3 mm (millimeters) and be spaced at a distance 194, for example, of 9 mm. Alternatively, the shielding device 190 located in the cooling channel 146 may be a foam, for example, a nickel foam.

[0057] The shielding device 190 in the cooling channel 146 has the advantage of allowing the gases to be evacuated to pass through while blocking any electromagnetic field to which the housing is exposed.

[0058] The invention effectively solves the problem it set for itself, namely to allow the evacuation of hot gases without damage to the evacuation valve on the one hand, and to guarantee the sealing of the housing against electromagnetic waves on the other.

[0059] Of course, the invention is not limited to the examples just described, and many modifications can be made to these examples without departing from the scope of the invention. In particular, the features of different embodiments of the invention can be combined to carry out the invention, provided that these embodiments are not incompatible with each other.

Claims

DEMANDS 1- Housing (110), particularly for a motor vehicle battery, comprising: a bottom wall (120), a lid wall (130) and a hollow side wall (140) extending between the bottom wall (120) and the lid wall (130) defining an internal housing (111), the hollow side wall (140) being delimited by an outer partition (141) and an inner partition (142), the internal housing (111) being configured to accommodate at least one energy storage unit (150), in particular a battery cell, and a vent valve (160) for gases from at least one energy storage unit (150), the vent valve being disposed in the outer partition (141) of the side hollow wall, the housing being characterized in that it further comprises at least one internal hollow wall (170) disposed in the inner housing (111), in particular forming a stiffening element of the housing and / or of separation of the inner housing (111), the internal hollow wall (170) being delimited by two internal partitions (171, 172) and comprising an end (173) opening into the hollow wall (140), and in that the internal hollow wall (170) has at least one internal opening (175) in at least one of the two internal partitions (171, 172), the hollow walls (140, 170) defining a gas cooling channel (146) from the at least one internal opening (175) to the discharge valve (160), so as to fluidly connect the inner housing (111) to the discharge valve (160). 2- Housing (110) according to claim 1, in which the hollow side wall (140) has at least one internal opening (145) in the internal partition (142). 3- Housing (110) according to claim 1 or 2, in which at least one of the at least one internal opening (175) and the at least one internal opening (145) is disposed at a distance (dl) from the lid wall (130) such that said at least one opening is closer to the lid wall (130) than to the bottom wall (120), said distance (dl) being preferably less than or equal to one third of the distance between the lid wall (130) and the bottom wall (120). 4- Housing (110) according to any one of claims 1 to 3, wherein at least one of the side hollow wall (140) and the internal hollow wall (170) having at least one opening (145, 175) further comprises an intermediate partition (147) partially dividing said hollow wall (140, 170) into: an upper zone (148) disposed above the intermediate partition (147) and into which at least one opening (145, 175) of said hollow wall opens, and a lower zone (149) disposed below the intermediate partition (147), the intermediate partition (147) comprising a passage (147) between the upper zone (148) and the lower zone (149) of said hollow wall, the cooling channel (146) extending through the lower zone (149) from at least one opening (145, 175) of the upper zone (148) up to the discharge valve (160). 5- Housing (110) according to any one of claims 1 to 4, comprising an electromagnetic shielding device (190) disposed in the cooling channel (146). 6- Housing (110) according to claim 5, in which the shielding device (190) covers at least one of the openings (145, 175) in the inner (142) or internal (171, 172) partition. 7- Housing (110) according to claim 5 or 6, in which the shielding device (190) comprises a plurality of orifices (191) of predefined dimensions. 8- Housing (110) according to any one of claims 5 to 7, in which the shielding device (190) is a metal grid (192) extending perpendicularly to one of the partitions (142, 171, 172) forming the cooling channel (146). 9- Battery (100) comprising at least one energy storage element, in particular a battery cell, and a housing (110) according to any one of claims 1 to 8, said storage element being disposed in the internal housing (111) of the housing (110).

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