Battery module with improved heat transfer prevention structure

Abstract

In one example, the disclosed battery module includes a module housing in which a plurality of battery cells are accommodated, a pair of high voltage terminals provided on a front surface of the module housing, a pair of module lifting holes provided between the high voltage terminals, a thermal barrier surrounding a portion of the front surface of the module housing including the high voltage terminals and having a fastening hole formed therethrough on an upper surface thereof, and a fastening member installed through the module lifting holes and the fastening hole to fix the thermal barrier to the module lifting holes.

Description

[Technical Field]

[0001] The present invention relates to a battery module, and more particularly to a battery module that can effectively prevent heat propagation caused by a thermal runaway phenomenon occurring in a battery cell within the battery module from spreading to other surrounding battery modules.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0124004, filed on September 29, 2022, and all contents disclosed in the documents of said Korean patent application are incorporated herein by reference. [Background technology]

[0003] Unlike primary batteries, secondary batteries are rechargeable and have the potential to be small and have large capacities, and as such, they have been the subject of much research and development in recent years. Demand for secondary batteries as an energy source is rapidly increasing due to the increasing technological development and demand for mobile devices, as well as the emergence of electric vehicles and energy storage systems in response to modern demands for environmental protection.

[0004] Secondary batteries are classified into coin-type batteries, cylindrical batteries, prismatic batteries, and pouch-type batteries depending on the shape of the battery case. The electrode assembly installed inside the battery case of a secondary battery is a power generating element that can be charged and discharged and is made up of a laminated structure of electrodes and a separator.

[0005] Since secondary batteries are required to be used continuously for long periods of time, it is necessary to effectively control the heat generated during the charging and discharging process.If secondary batteries are not cooled smoothly, a positive feedback chain reaction will occur in which a rise in temperature causes an increase in current, which in turn causes a rise in temperature again, resulting in a catastrophic state of thermal runaway.

[0006] Furthermore, when secondary batteries are grouped together in the form of a module or pack, thermal runaway in one secondary battery can cause the other surrounding secondary batteries to continuously overheat, resulting in a thermal propagation phenomenon. In other words, when thermal runaway occurs in a battery module within a battery pack, a large amount of conductive dust, gas, and flames are emitted from the high-voltage terminal of the battery module, causing dust to accumulate at the high-voltage terminals of other adjacent battery modules, and the heat transfer caused by the gas and flames triggers the thermal propagation phenomenon.

[0007] To prevent this heat transfer, a method was devised to add a flame-retardant thermal barrier to prevent the transfer of ejected material and high heat to adjacent battery modules, but there was a problem that the thermal barrier frequently came out of its original position due to the high-temperature and high-pressure material ejected from the battery module, preventing it from functioning properly. Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present invention is to provide a battery module that can more effectively block conductive dust, gas, and flames that are emitted in large quantities from high-voltage terminals by firmly maintaining the position of a thermal barrier when a thermal runaway phenomenon occurs in the battery module.

[0009] However, the technical problems that the present invention aims to solve are not limited to the above-mentioned problems, and other problems not mentioned will be clearly understood by those skilled in the art from the description of the invention described below. [Means for solving the problem]

[0010] The present invention relates to a battery module, and in one example, the battery module includes a module housing in which a plurality of battery cells are accommodated, a pair of high-voltage terminals provided on a front surface of the module housing, a pair of module lifting holes provided between the high-voltage terminals, a thermal barrier that surrounds a portion of the front surface of the module housing including the high-voltage terminals and has fastening holes formed therethrough on an upper surface thereof, and fastening members installed through the module lifting holes and the fastening holes to fix the thermal barrier to the module lifting holes.

[0011] In an embodiment of the present invention, the module lifting hole is formed on the upper surface of a module lifting rib that forms a step with respect to the upper surface of the module housing and forms a space that is open to the front surface of the module housing.

[0012] The thermal barrier may have a bent shape surrounding the upper and front surfaces of the high voltage terminal.

[0013] Additionally, the width of the thermal barrier may correspond to the width of the front surface of the module housing.

[0014] The fastening member may include a nut inserted into the interior of the module lifting rib, a washer disposed on the upper surface of the module lifting rib, and a bolt passing through the fastening hole, washer, and module lifting hole to threadably engage with the nut.

[0015] Here, it is preferable that the nut is installed inside the module lifting rib so as not to rotate together with the rotation of the bolt.

[0016] Alternatively, the fastening member may be a rivet that is installed through the fastening hole and the module lifting hole.

[0017] Heat-resistant silicone may be applied to the contact surface between the thermal barrier and the module housing.

[0018] Meanwhile, according to another embodiment of the present invention, the battery module further includes bus bars and bus bar covers surrounding the bus bars, and both ends of the bus bars are mechanically fixed to high-voltage terminals of adjacent module housings and electrically connected to each other.

[0019] The bus bar cover may include a bus bar lower cover on which the bus bar is seated and which has connection holes that expose the bus bar to the high-voltage terminal, and a bus bar upper cover that is coupled to the bus bar lower cover to surround the bus bar and which has cover fastening holes that correspond to the module lifting holes.

[0020] The bus bar lower cover and the bus bar upper cover may be connected to each other by a hook structure.

[0021] It can be said that it is preferable that the thermal barrier surrounds the bus bar cover.

[0022] Here, the fastening member may pass through the fastening hole of the thermal barrier and the cover fastening hole of the bus bar cover and be fastened to the module lifting hole.

[0023] Such fastening members may be nuts inserted into the interior of the module lifting rib, and bolts threadedly connected to the nuts by passing through the fastening holes, cover fastening holes, and module lifting holes, or rivets installed by passing through the fastening holes, cover fastening holes, and module lifting holes.

[0024] A concave stepped surface may be formed around the fastening hole of the thermal barrier, corresponding to the step formed by the module lifting rib with respect to the upper surface of the module housing. [Effects of the Invention]

[0025] In the battery module of the present invention having the above-described configuration, the thermal barrier can be mechanically and firmly fixed using the module lifting holes already provided in the module housing in order to handle the heavy battery module. As a result, even if thermal runaway occurs in the battery module and a large amount of material spills out from the high-voltage terminal, the thermal barrier can firmly maintain its position, thereby effectively blocking or delaying heat transfer to other surrounding battery modules.

[0026] In addition, the battery module of the present invention can more effectively prevent heat propagation by protecting the high voltage terminals and bus bars with a flame-retardant cover.

[0027] However, the technical effects that can be obtained by the present invention are not limited to the effects described above, and other effects not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0028] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention described below, serve to further understand the technical concept of the present invention, and therefore the present invention should not be interpreted as being limited solely to the matters depicted in such drawings. [Brief explanation of the drawings]

[0029] [Figure 1] 1 is a diagram showing an example of a battery pack including a plurality of battery modules according to the present invention; [Figure 2] 1 is a diagram showing a battery module without a thermal barrier. [Figure 3] 1 is an enlarged view of the front surface of a battery housing to which a thermal barrier is attached. [Figure 4] FIG. 2 is an exploded perspective view showing the mounting structure of the thermal barrier. [Figure 5] 1 is a diagram showing a battery module equipped with a thermal barrier. [Figure 6] 10 is a view showing a bus bar cover provided in another embodiment of the present invention; [Figure 7] 1 is a view showing a structure in which a bus bar cover is attached to a battery module; [Figure 8] 1 is a diagram showing a battery module including a thermal barrier and a bus bar cover. [Figure 9] FIG. 9 is a cross-sectional view taken along line "AA" in FIG. 8. [Figure 10] 10 is a view showing another embodiment of a thermal barrier. DETAILED DESCRIPTION OF THE INVENTION

[0030] Because the present invention is susceptible to various modifications and can have various embodiments, specific embodiments will be described in detail below.

[0031] However, this is not intended to limit the invention to any particular embodiment, but rather to be understood as including all modifications, equivalents, or alternatives falling within the spirit and scope of the invention.

[0032] In the present invention, terms such as "comprise" and "have" are intended to specify the presence of features, numbers, steps, operations, components, parts or combinations thereof described in the specification, and may be understood as not precluding the presence or possibility of addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0033] Furthermore, in the present invention, when a layer, film, region, plate, or other portion is described as being "on" another portion, this includes not only the case where it is "directly on" the other portion, but also the case where there is another portion therebetween. Conversely, when a layer, film, region, plate, or other portion is described as being "under" the other portion, this includes not only the case where it is "directly under" the other portion, but also the case where there is another portion therebetween. Furthermore, in this application, being "located on" can include not only the case where it is located at the top, but also the case where it is located at the bottom.

[0034] The present invention relates to a battery module, and in one example, the battery module includes a module housing in which a plurality of battery cells are accommodated, a pair of high-voltage terminals provided on a front surface of the module housing, a pair of module lifting holes provided between the high-voltage terminals, a thermal barrier that surrounds a portion of the front surface of the module housing including the high-voltage terminals and has fastening holes formed therethrough on an upper surface thereof, and fastening members installed through the module lifting holes and the fastening holes to fix the thermal barrier to the module lifting holes.

[0035] In the battery module of the present invention having such a configuration, the thermal barrier can be mechanically and firmly fixed using the module lifting holes already provided in the module housing in order to handle the heavy battery module. As a result, even if thermal runaway occurs in the battery module and a large amount of material spills out from the high-voltage terminal, the thermal barrier can firmly maintain its position, thereby effectively blocking or delaying heat transfer to other surrounding battery modules.

[0036] Hereinafter, specific embodiments of a battery module according to the present invention will be described in detail with reference to the accompanying drawings. For reference, directions such as front-back, up-down, left-right, and right-left used in the following description are intended to facilitate understanding of the invention, and unless otherwise specified, are based on directions shown in the drawings.

[0037] (First embodiment) FIG. 1 is a diagram showing an example of a battery pack 10 equipped with a plurality of battery modules 100 according to the present invention. The battery pack 10 includes a pack case 12 having a frame structure that forms a space for accommodating a plurality of battery modules 100, protects the installed battery modules 100, and ensures the structural rigidity of the battery pack 10. The battery pack 10 illustrated in FIG. 1 includes a total of eight battery modules 100, which are arranged with their front faces facing a center frame 14 that crosses the center of the pack case 12. A high-voltage terminal 120 for connecting a bus bar 500 is disposed on the front of the battery module 100, and a thermal barrier 200 for protecting the high-voltage terminal 120 is attached to the battery module 100.

[0038] 2 shows one of the battery modules 100 installed in the battery pack 10 of FIG. 1, with the thermal barrier 200 shown in FIG. 1 omitted. The battery module 100 contains a plurality of battery cells (internal battery cells are not shown in the drawing), which are connected to each other in series and / or parallel circuits so that charging and discharging occur at a specified voltage and current. A high-voltage terminal 120 is provided on the outside of the battery module 100 as an input / output terminal for the electrically connected battery cells.

[0039] 3 is an enlarged view of the front surface of the module housing 110 to which the thermal barrier 200 is attached. The module housing 110 is a part that forms the main body of the battery module 100 that houses a plurality of battery cells, and a pair of high-voltage terminals 120 are provided on the front surface of the module housing 110.

[0040] A pair of module lifting holes 132 are provided between the pair of high-voltage terminals 120 consisting of a positive electrode and a negative electrode. Because the battery module 100 equipped with a plurality of battery cells is quite heavy, a lifting device is used to insert or remove the battery module 100 into or from the battery pack 10. The module lifting holes 132 are provided in the module housing 110 to facilitate handling of the battery module 100, and a pair of module lifting holes 132 are provided on each of the front and rear surfaces of the module housing 110 for balance.

[0041] The thermal barrier 200 is a partition member for blocking a large amount of conductive dust, gas, and flames that are discharged at high temperature and pressure toward the high-voltage terminal 120 when thermal runaway occurs inside the battery module 100. For this purpose, the thermal barrier 200 surrounds a portion of the front surface of the module housing 110 and is made of a flame-retardant material that can withstand high temperatures, such as mica. The thermal barrier 200 has fastening holes 210 formed through its upper surface for fastening to the module housing 110.

[0042] The thermal barrier 200 is fixed to the module housing 110 by a fastening member 300. Conventionally, the thermal barrier 200 has been fixed to the module housing 110 by attaching it with imide tape or heat-resistant silicone. However, while this attachment method is simple, it has the disadvantage of not providing sufficient fixing strength for the thermal barrier 200. In particular, high-temperature, high-pressure ejected material can cause the thermal barrier 200 to move out of position, making it difficult to trust its reliable blocking function. In contrast, in the present invention, the fastening member 300 is installed by passing through the module lifting hole 132 and the fastening hole 210, thereby greatly improving the mechanical fixation of the thermal barrier 200.

[0043] 3, the module lifting hole 132 is formed on the upper surface of the module lifting rib 130, forming a step with respect to the upper surface of the module housing 110 and forming an open space toward the front surface of the module housing 110. The thermal barrier 200 has a bent shape that surrounds the upper and front surfaces of the high-voltage terminal 120. Both sides of the thermal barrier 200 are open to allow the bus bar 500 to be pulled out, i.e., to connect the bus bar 500 to another adjacent battery module 100, but by surrounding the upper and front surfaces of the high-voltage terminal 120, the discharge and diffusion of ejected materials are minimized. In addition, it is preferable that the width of the thermal barrier 200 has a length that corresponds to the front width of the module housing 110, thereby ensuring the maximum coverage area.

[0044] Fig. 4 is an exploded perspective view showing the mounting structure of the thermal barrier 200, and Fig. 5 is a view showing the battery module 100 mounted with the thermal barrier 200. The module lifting rib 130, in which the module lifting hole 132 is formed, forms an open space toward the front surface of the module housing 110, and by using this space, the fastening member 300 can be easily installed even if the front and top surfaces are blocked by the bent thermal barrier 200.

[0045] Referring to FIG. 4, the fastening member 300 includes a nut 310 inserted into the interior of the module lifting rib 130, a washer 312 placed on the upper surface of the module lifting rib 130, and a bolt 314 that passes through the fastening hole 210 and washer 312 of the thermal barrier 200 and the module lifting hole 132 and threads into the nut 310.

[0046] Here, the nut 310 is preferably configured so as not to rotate with the rotation of the bolt 314 and is installed inside the module lifting rib 130. For example, the nut 310 may be a square nut, and since the nut 310 is installed semi-fixedly inside the module lifting rib 130, the torque of the bolt 314 is completely transmitted to the screw tightening of the nut 310. This fastening structure allows the fastening member 300 to be easily installed even when the module lifting hole 132 is blocked by the thermal barrier 200. For reference, as shown in FIG. 4, the nut 310 may also be a square nut.

[0047] Alternatively, in order to reduce the number of components of the fastening member 300, thereby reducing costs and improving processes, the fastening member 300 may be configured with a rivet 320 that is installed by passing through the fastening hole 210 and the module lifting hole 132 (see FIG. 10). For example, after the nail-shaped rivet 320 is inserted into the fastening hole 210 and the module lifting hole 132, the riveting can be completed using a rivet gun. However, unlike the bolt 314 and nut 310, the rivet fastening has the disadvantage that it cannot be repeatedly fastened and disassembled. Therefore, it is preferable to select a suitable fastening member 300 taking into consideration the need for disassembly, etc.

[0048] To ensure additional assembly rigidity of the thermal barrier 200, heat-resistant silicone 330 may be applied to the contact surface between the thermal barrier 200 and the module housing 110, and then the fastening member 300 may be fastened (see FIG. 10). The adhesive strength of the heat-resistant silicone 330 combined with the fastening strength of the fastening member 300 allows the thermal barrier 200 to be very firmly fixed to the module housing 110.

[0049] (Second embodiment) The second embodiment of the present invention includes a bus bar cover 400 for protecting the bus bar 500. Referring to Fig. 1, eight battery modules 100 are arranged with their front faces facing the center frame 14 that crosses the center of the pack case 12, and thus the thermal barriers 200 are arranged side by side adjacent to the center frame 14.

[0050] As described above, since both sides of the thermal barrier 200 are open to allow connection of the bus bars 500, ejected material from a battery module 100 experiencing thermal runaway is effectively blocked for the battery modules 100 across the center frame 14, but the blocking effect is poor for battery modules 100 connected in a row with thermal barriers 200. The high-temperature ejected material is likely to damage the high-voltage terminals 120 and bus bars 500 of adjacent battery modules 100, and there is also concern about heat propagation due to the accumulation of ejected material.

[0051] The second embodiment of the present invention can more effectively prevent heat propagation by protecting the high-voltage terminals 120 and bus bars 500 of the battery module 100 with a flame-retardant cover. Fig. 6 is a view showing a bus bar cover 400 provided in the second embodiment of the present invention, and Fig. 7 is a view showing a structure in which the bus bar cover 400 is attached to the battery module 100.

[0052] Referring to the drawings, the battery module 100 includes a bus bar 500 and a bus bar cover 400 that entirely surrounds the bus bar 500, and both ends of the bus bar 500 protected by the bus bar cover 400 are mechanically fixed to the high voltage terminals 120 of the adjacent module housing 110, respectively, and are electrically connected to each other.

[0053] Here, bus bar cover 400 is made up of two pieces: bus bar lower cover 410 and bus bar upper cover 420. Bus bar lower cover 410 is a lower structure that supports and seats the bottom of bus bar 500, and has connection holes 412 that expose bus bar 500 to high voltage terminals 120 of module housing 110. Bus bar upper cover 420 is an upper structure that is combined with bus bar lower cover 410 to surround bus bar 500, and has cover fastening holes 422 that correspond to module lifting holes 132.

[0054] Since the bus bar cover 400 is configured to surround the entire bus bar 500, the bus bar 500 is assembled to the module housing 110 in the following order: the bus bar 500 is seated on the bus bar lower cover 410, the bus bar 500 is fixed to the high-voltage terminal 120 through the connection holes 412 of the bus bar lower cover 410, and then the bus bar upper cover 420 is coupled. In this regard, it is preferable from the perspective of ease of assembly to configure the bus bar lower cover 410 and the bus bar upper cover 420 so that they can be coupled to each other in a one-touch manner using the hook 414 structure.

[0055] Fig. 8 is a view showing a battery module 100 including a thermal barrier 200 and a bus bar cover 400, and Fig. 9 is a cross-sectional view taken along line AA in Fig. 8. The bus bar covers 400 are coupled to a pair of high-voltage terminals 120, one for each, and are extended to a length that allows them to be connected to the high-voltage terminals 120 of an adjacent battery module 100. The thermal barrier 200 is coupled to the bus bar cover 400 so as to surround it. This double covering of the high-voltage terminals 120 further prevents ejected material from being discharged to the outside in a battery module 100 that has experienced thermal runaway, and further suppresses the inflow of ejected material into other adjacent battery modules 100.

[0056] In the second embodiment, the bus bar cover 400 and the thermal barrier 200 are fixed simultaneously. In other words, both the bus bar cover 400 and the thermal barrier 200 are fixed to the same module lifting hole 132 of the module housing 110. Referring to Fig. 9, the fastening member 300 passes through the fastening hole 210 of the thermal barrier 200 and the cover fastening hole 422 of the bus bar cover 400, and is fastened to the module lifting hole 132. Because the bus bar cover 400 and the thermal barrier 200 can be fixed at the same time with one fastening member 300, the assembly process is improved and the number of parts is reduced, which helps to improve costs.

[0057] In addition, the bus bar cover 400 has a space for accommodating the bus bar 500 and a fixing portion of the bus bar cover 400 separated from each other. That is, the cover fastening hole 422 of the bus bar upper cover 420 does not communicate with the space for accommodating the bus bar 500, thereby ensuring the hermeticity of the high voltage terminal 120.

[0058] Similar to the first embodiment, the fastening member 300 in the second embodiment may be a nut 310 inserted into the module lifting rib 130, a bolt 314 passing through the fastening hole 210, the cover fastening hole 422, and the module lifting hole 132 to threadably engage with the nut 310, or a rivet 320 passing through the fastening hole 210, the cover fastening hole 422, and the module lifting hole 132. However, because the bus bar upper cover 420 is interposed between the thermal barrier 200 and the module lifting hole 132, there is little need to provide an additional washer 312 to prevent loosening. Similarly, heat-resistant silicone 330 may be applied to the contact surface between the thermal barrier 200 and the module housing 110 to ensure additional assembly rigidity of the thermal barrier 200.

[0059] FIG. 10 is a view showing another embodiment of a thermal barrier 200. For reference, FIG. 10 shows a rivet 320, which is a fastening member 300, and heat-resistant silicone 330 for ensuring additional assembly rigidity. The thermal barrier 200 shown in FIGS. 7 to 10 has a recessed stepped surface 220 formed around the fastening hole 210. The stepped surface 220 of the thermal barrier 200 may be formed to a size corresponding to the step formed by the module lifting rib 130 relative to the upper surface of the module housing 110. The stepped surface 220 of the thermal barrier 200 reduces the gap between the thermal barrier 200 and the high-voltage terminal 120, thereby improving the protection effect around the high-voltage terminal 120.

[0060] The present invention has been described in more detail above with reference to the drawings and embodiments, etc. However, the configurations shown in the drawings or embodiments in this specification are merely one embodiment of the present invention and do not represent all of the technical ideas of the present invention, and therefore, there may be various equivalents and modifications that can replace them at the time of filing this application. [Explanation of symbols]

[0061] 10: Battery pack 12: Pack case 14: Center frame 100: Battery module 110: Module housing 120: High voltage terminal 130:Module lifting rib 132: Module lifting hole 200: Thermal Barrier 210: Concluding hole 220: Step surface 300: Fastening member 310: Nut 312: Washer 314: Bolt 320: Rivet 330: Heat-resistant silicone 400: Busbar cover 410: Busbar bottom cover 412: Connection hole 414: Hook 420: Busbar upper cover 422: Cover fastening hole 500: Busbar

Claims

1. a module housing containing a plurality of battery cells; a pair of high voltage terminals provided on the front surface of the module housing; a pair of module lifting holes provided between the high voltage terminals; a thermal barrier surrounding a portion of the front surface of the module housing including the high-voltage terminal, the thermal barrier having a fastening hole formed through an upper surface thereof; a fastening member installed through the module lifting hole and the fastening hole to fix the thermal barrier to the module lifting hole, The module lifting hole is The battery module is formed on the upper surface of a module lifting rib that forms a step with respect to the upper surface of the module housing and forms a space that is open to the front surface of the module housing.

2. The thermal barrier is The battery module according to claim 1 , wherein the high-voltage terminal has a folded shape surrounding an upper surface and a front surface of the high-voltage terminal.

3. The battery module according to claim 2 , wherein the width of the thermal barrier is equal to the width of the front surface of the module housing.

4. The fastening member is a nut inserted into the interior of the module lifting rib; a washer disposed on an upper surface of the module lifting rib; The battery module according to claim 1 , further comprising: a bolt passing through the fastening hole, a washer, and the module lifting hole and threadedly coupled to the nut.

5. The battery module according to claim 4 , wherein the nut is installed inside the module lifting rib so as not to rotate together with the rotation of the bolt.

6. The fastening member is The battery module according to claim 1 , wherein the rivet is installed through the fastening hole and the module lifting hole.

7. The battery module according to claim 1 , wherein a heat-resistant silicone is applied to a contact surface between the thermal barrier and the module housing.

8. further comprising a bus bar and a bus bar cover surrounding the bus bar; The battery module according to claim 2 , wherein both ends of the bus bar are mechanically fixed to high-voltage terminals of adjacent module housings and electrically connected to each other.

9. The bus bar cover is a bus bar lower cover having a connection hole on which the bus bar is seated and through which the bus bar is exposed to the high voltage terminal; a bus bar upper cover coupled to the bus bar lower cover to surround the bus bar, the bus bar upper cover having cover fastening holes corresponding to the module lifting holes.

10. The battery module of claim 9 , wherein the bus bar lower cover and the bus bar upper cover are connected to each other by a hook structure.

11. The battery module according to claim 9 , wherein the thermal barrier surrounds the bus bar cover.

12. The fastening member is The battery module according to claim 11 , wherein the battery module is fastened to the module lifting hole through the fastening hole of the thermal barrier and the cover fastening hole of the bus bar cover.

13. The fastening member is a nut inserted into the module lifting rib, and a bolt passing through the fastening hole, the cover fastening hole, and the module lifting hole to be screwed to the nut; The battery module according to claim 12 , wherein the fastening hole, the cover fastening hole, and the module lifting hole are rivets installed through the fastening hole, the cover fastening hole, and the module lifting hole.

14. The battery module according to claim 2 , wherein a concave stepped surface is formed around the fastening hole of the thermal barrier, the concave stepped surface corresponding to a step formed between the module lifting rib and the upper surface of the module housing.

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