BATTERY MODULE WITH IMPROVED HEAT PROPAGATION PREVENTION STRUCTURE

A battery module includes a module housing accommodating a plurality of battery cells; a pair of high-voltage terminals provided on the front of the module housing; a pair of module lifting holes provided between the high-voltage terminals; a thermal barrier that wraps around part of the front of the module housing including the high-voltage terminals, with fastening holes penetrating through its upper surface; and a fastening member installed by penetrating through the module lifting hole and fastening hole to secure the thermal barrier to the module lifting hole.

TECHNICAL FIELD

The present invention relates to a battery module, which is capable of effectively preventing the thermal propagation of thermal runaway occurring in a battery cell within the battery module to other surrounding battery modules.

This application claims the benefit of priority to Korean Patent Application No. 10-2022-0124004, filed on Sep. 29, 2022, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND TECHNOLOGY OF THE INVENTION

Unlike primary batteries, secondary batteries can be recharged, and they have been heavily researched and developed in recent years due to their potential for miniaturization and large capacity. The demand for secondary batteries as an energy source is increasing rapidly due to the technological development and increasing demand for mobile devices, electric vehicles, and energy storage systems, which are emerging in response to the need for environmental protection.

Secondary batteries are categorized into coin-type cells, cylindrical cells, prismatic cells, and pouch-type cells based on the shape of the cell case. In a secondary battery, an electrode assembly mounted inside the battery case is a chargeable/dischargeable power generator consisting of a laminated structure of electrodes and separators.

Since secondary batteries are required for continuous use over a long period, it is necessary to effectively control the heat generated during the charging and discharging process. If the cooling of the secondary battery is not carried out smoothly, the temperature rise can lead to an increase in current, and the increase in current causes the temperature to rise again, creating a feedback chain reaction that eventually leads to the catastrophic condition of thermal runaway.

Additionally, when secondary batteries form a group in the form of modules or packs, the occurrence of thermal runaway in one secondary battery can lead to a thermal propagation phenomenon where the surrounding batteries get successively overheated. That is, when thermal runaway occurs in a battery module within the battery pack, a large amount of conductive dust, gas, and flames are emitted from the high-voltage terminals of the battery module. As a result, dust accumulates on the high-voltage terminals of other neighboring battery modules, and heat transfer by gas and flame triggers the phenomenon of thermal propagation.

To prevent this thermal propagation, measures were taken to add a flame-retardant thermal barrier to prevent the transfer of ejecta and high heat to adjacent battery modules. However, there has been a problem in that the thermal barrier often gets dislocated from its proper position due to the high-temperature, high-pressure substances ejected from the battery module, thus failing to function effectively.

DESCRIPTION OF THE INVENTION

Technical Problem

The present invention aims to provide a battery module that can more effectively block conductive dust, gases, and flames that are emitted in large quantities from high-voltage terminals by keeping the thermal barrier firmly in place in the event of thermal runaway in the battery module.

However, the technical problems to be solved by the present invention are not limited to the above-described problem, and other problems not mentioned can be clearly understood by those skilled in the art from the following description of the present invention.

Technical Solution

The present invention relates to a battery module which, in one example, includes a module housing accommodating a plurality of battery cells; a pair of high-voltage terminals provided on the front of the module housing; a pair of module lifting holes provided between the pair of high-voltage terminals; a thermal barrier that wraps around part of a front of the module housing including the pair of high-voltage terminals, with a pair of fastening holes penetrating through an upper surface of the thermal barrier; and a pair of fastening members respectively penetrating through the pair of module lifting holes and pair of fastening holes to secure the thermal barrier to the module housing.

In an exemplary embodiment of the invention, the pair of module lifting holes are formed on an upper surface of pair of module lifting ribs that each create an open space on the front of the module housing, while forming a step relative to an upper surface of the module housing.

Additionally, the thermal barrier may form a bent shape that wraps around an upper surface and a front surface of the pair of high-voltage terminals.

Furthermore, a width of the thermal barrier may correspond to a front width of the module housing.

Furthermore, each fastening member may include a nut inserted inside the module lifting rib, a washer placed on the upper surface of the module lifting rib, and a bolt that screws into the nut through the fastening hole, the washer, and the module lifting hole.

Here, it may be preferable that the nut is installed inside the module lifting rib in a manner that prevents it from rotating together with the rotation of the bolt.

Alternatively, each fastening member may be a rivet installed through a respective fastening hole and a respective module lifting hole.

Additionally, a heat-resistant silicone may be applied to a contact surface between the thermal barrier and the module housing.

In another exemplary embodiment of the invention, the battery module further includes a busbar, and a busbar cover that wraps around the busbar, wherein ends of the busbar are mechanically fixed to the pair of high-voltage terminals of adjacent module housing, respectively.

The busbar cover may include a lower busbar cover in which the busbar is seated, and is provided with a connection hole exposing the busbar to the pair of high-voltage terminals; and an upper busbar cover for wrapping around the busbar in combination with the lower busbar cover, and is provided with a pair of cover fastening holes corresponding to the module lifting holes.

Furthermore, the lower busbar cover and the upper busbar cover may be mutually coupled by a hook structure.

Additionally, it may be preferable for the thermal barrier to wrap around the busbar cover.

Here, each fastening member may be fastened to a respective module lifting hole through a respective fastening hole in the thermal barrier and through a respective cover fastening hole in the busbar cover.

Such a fastening member may be a nut inserted into the interior of the module lifting rib, and a bolt threaded to the nut through the respective fastening hole in the thermal barrier, through the respective cover fastening hole, and through the respective module lifting hole, or a rivet installed through the respective fastening hole in the thermal barrier, through the respective cover fastening hole, and through the respective module lifting hole.

Additionally, around each of the pair of fastening holes in the thermal barrier, a concave stepped surface may be formed corresponding to the step formed by a respective one of the pair of module lifting ribs relative to the upper surface of the module housing.

Advantageous Effects

The battery module of the present invention with the above configuration can mechanically secure the thermal barrier by utilizing the module lifting holes already provided in the module housing for handling heavy battery modules. Thus, even if a thermal runaway occurs in the battery module and a large amount of spillage from the high-voltage terminals occurs, the thermal barrier may remain firmly in place, effectively blocking or delaying heat propagation to other battery modules in the vicinity.

Furthermore, by protecting the high-voltage terminals and busbar with a flame-retardant cover, the battery module of the present invention enables even more effective prevention of heat propagation.

However, the technical effects that can be obtained through the present invention are not limited to those described above, and other effects not mentioned will be apparent to one of ordinary skill in the art from the following description of the invention.

BEST MODE FOR INVENTION

The present invention may have various modifications and various examples, and specific examples are illustrated in the drawings and described in detail in the description.

However, it should be understood that the present invention is not limited to specific embodiments, and includes all modifications, equivalents or alternatives within the spirit and technical scope of the present invention.

The terms “comprise,” “include” and “have” are used herein to designate the presence of characteristics, numbers, steps, actions, components or members described in the specification or a combination thereof, and it should be understood that the possibility of the presence or addition of one or more other characteristics, numbers, steps, actions, components, members or a combination thereof is not excluded in advance.

In addition, when a part of a layer, a film, a region or a plate is disposed “on” another part, this includes not only a case in which one part is disposed “directly on” another part, but a case in which a third part is interposed there between. In contrast, when a part of a layer, a film, a region or a plate is disposed “under” another part, this includes not only a case in which one part is disposed “directly under” another part, but a case in which a third part is interposed there between. In addition, in this application, “on” may include not only a case of disposed on an upper part but also a case of disposed on a lower part.

The present invention relates to a battery module which, in one example, includes a module housing accommodating a plurality of battery cells; a pair of high-voltage terminals provided on the front of the module housing; a pair of module lifting holes provided between the high-voltage terminals; a thermal barrier that wraps around part of the front of the module housing including the high-voltage terminals, with fastening holes penetrating through its upper surface; and a fastening member installed by penetrating through the module lifting hole and fastening hole to secure the thermal barrier to the module lifting hole.

With this configuration, the battery module of the present invention can mechanically fix the thermal barrier by utilizing the module lifting holes already provided in the module housing for handling heavy battery modules. Thus, even if a thermal runaway occurs in the battery module and a large amount of spillage is generated from the high-voltage terminals, the thermal barrier can remain firmly in place, effectively blocking or delaying heat propagation to other battery modules in the vicinity.

MODE FOR INVENTION

Hereinafter, specific embodiments of a pack case according to the present invention will be described in detail with reference to the accompanying drawings. For reference, the directions of front, back, up, down, left and right designating relative positions used in the following description are for the purpose of understanding the invention, and refer to the directions shown in the drawings unless otherwise specified.

First Embodiment

FIG.1is a drawing illustrating an example of a battery pack10in which a plurality of battery modules100of the present invention is mounted. The battery pack10includes a pack case12made into a framed structure that forms a space for accommodating the plurality of battery modules100while protecting the mounted battery modules100and ensuring structural rigidity of the battery pack10. The battery pack10, exemplarily shown inFIG.1, has a total of eight battery modules100mounted on it, with the fronts of the battery modules100arranged to face toward a center frame14that runs across the center of the pack case12. A high-voltage terminal120for connecting a busbar500is arranged on the front of the battery module100, and a thermal barrier200for protecting it is mounted on the battery module100.

FIG.2illustrates one battery module100mounted on the battery pack10ofFIG.1, with the thermal barrier200shown inFIG.1omitted. The battery module100contains a plurality of battery cells (the battery cells inside are not shown in the drawing), and the plurality of battery cells are connected to each other in a series and/or parallel circuit such that charging and discharging occurs at a prescribed voltage and current. High-voltage terminals120are provided on the exterior of the battery module100as input and output terminals for the plurality of electrically connected battery cells.

FIG.3is an enlarged view of the front of a module housing110in which a thermal barrier200is mounted. The module housing110is a portion of the body of the battery module100that accommodates a plurality of battery cells, and is provided with a pair of high-voltage terminals120on the front of the module housing110.

Further, a pair of module lifting holes132are provided between the high-voltage terminals120consisting of positive electrode and negative electrode as a pair. Since the battery module100mounted with a plurality of battery cells can be quite heavy, a lifting device is utilized to perform storage or removal operations for the battery pack10. For handling such a battery module100, module lifting holes132are provided in the module housing110, and for balance, a pair of module lifting holes132are provided at the front and rear of the module housing110.

The thermal barrier200is a bulkhead member for blocking a large amount of conductive dust, gas, and flame that is emitted at high temperature and pressure toward the high-voltage terminal120in the event of a thermal runaway within the battery module100. For this purpose, the thermal barrier200is shaped to wrap around a front portion of the module housing110and is made of a flame-retardant material that can withstand high temperatures, for example, a mica material. Furthermore, the upper surface of the thermal barrier200has a fastening hole210formed through it for fixing to the module housing110.

The fixation of the thermal barrier200to the module housing110is accomplished by the fastening member300, and conventionally, the thermal barrier200is fixed to the module housing110by attaching the thermal barrier200with an adhesive tape or heat-resistant silicone. Although the attachment method is simple, it has the disadvantage of insufficient fixing force of the thermal barrier200, especially when the thermal barrier200is moved out of its position by a high-temperature/pressure spillage, thus it is difficult to trust the reliable blocking function. In comparison, in the present invention, the mechanical fixity of the thermal barrier200is greatly improved by the fastening member300being installed through the module lifting hole132and the fastening hole210.

Referring toFIG.3, module lifting holes132are formed in the upper surface of module lifting ribs130, which forms an open space for the front of module housing110while forming a step relative to the upper surface of module housing110. And, thermal barrier200has a bent shape that wraps around the upper surface and front surface of the high-voltage terminal120. Both sides of the thermal barrier200are open for the withdrawal of the busbar500, i.e., for the connection of the busbar500to other adjacent battery modules100, but by wrapping around the upper surface and front surface of the high-voltage terminal120, the emission and spread of spillage is prevented as much as possible. Further, it may be desirable for the width of the thermal barrier200to have a length corresponding to the front width of the module housing110to ensure maximum coverage area.

FIG.4is an exploded perspective view illustrating the mounting structure of the thermal barrier200, andFIG.5is a drawing illustrating the battery module100with the thermal barrier200mounted. The module lifting ribs130, in which the module lifting holes132are formed, form an open space relative to the front of the module housing110, which allows for easy installation of a fastening member300even when the front and upper surface are blocked by the bent thermal barrier200.

Referring toFIG.4, the fastening member300includes a nut310that is inserted into the interior of the module lifting rib130, a washer312disposed on the upper surface of the module lifting rib130, a bolt314that threads through the fastening hole210and the washer312of the thermal barrier200and through the module lifting hole132to be screwed into the nut310.

Here, the nut310is preferably installed on the interior of the module lifting rib130with a structure that does not rotate with the rotation of the bolt314. For example, the nut310may be a square nut, and as the nut310is semi-fixedly installed on the interior of the module lifting rib130, the torque of the bolt314is solely connected to the nut310by screw fastening. With this fastening structure, the fastening member300can be easily installed even when the module lifting hole132is blocked by the thermal barrier200. Note that the nut310can also be a square nut, as shown inFIG.4.

Alternatively, to reduce costs and improve processes by reducing the number of parts in the fastening member300, the fastening member300may be configured with rivets320that are installed through the fastening holes210and module lifting holes132(seeFIG.10). For example, a nail-like rivet320may be driven through the fastening hole210and the module lifting hole132, and then a rivet gun may be used to complete the rivet fastening. However, unlike the bolts314and nuts310, the rivet fastening has the disadvantage that it cannot be repeatedly fastened and disassembled, so it may be desirable to select the appropriate fastening member300in consideration of the need for disassembly.

And, to provide additional assembly rigidity of the thermal barrier200, the fastening member300may be engaged after the heat-resistant silicone330is applied to the contact surface of the thermal barrier200and the module housing110(seeFIG.10). The combination of the adhesion of the heat-resistant silicone330and the fastening force of the fastening member300ensures that the thermal barrier200is very firmly secured to the module housing110.

Second Embodiment

A second embodiment of the present invention includes a busbar cover400to protect the busbar500. Referring toFIG.1, eight battery modules100are arranged with the faces of the eight battery modules facing toward a center frame14that runs across the center of the pack case12, whereby the thermal barrier200is disposed side-by-side adjacent to the center frame14.

As described above, both sides of the thermal barrier200are open for connection to the busbar500, so that ejecta from a thermally runaway battery module100is effectively blocked for battery modules100beyond the center frame14, but is less effective for battery modules100connected in series with the thermal barrier200. The high-voltage terminals120and busbar500of adjacent battery modules100are susceptible to damage by a high-temperature ejecta, and thermal propagation by deposition of ejecta is also a concern.

By protecting the high-voltage terminals120and the busbar500of the battery module100with a flame-retardant cover, the second embodiment of the present invention enables more effective thermal propagation prevention to be realized.FIG.6is a drawing of a busbar cover400provided in a second embodiment of the present invention, andFIG.7is a drawing of a structure in which the busbar cover400is mounted to the battery module100.

Referring to the drawings, the battery module100includes a busbar500and a busbar cover400that encloses the entirety of the busbar500, with both ends of the busbar500protected by the busbar cover400being electrically coupled to each other by being mechanically fixed to high-voltage terminals120of an adjacent module housing110.

Here, the busbar cover400is a two-piece consisting of a lower busbar cover410and upper busbar cover420. The lower busbar cover410is a substructure that supports and seats the bottom surface of the busbar500, and includes a connection hole412that exposes the busbar500to the high-voltage terminals120of the module housing110. The upper busbar cover420is a superstructure coupled to the lower busbar cover410to enclose the busbar500, and includes cover fastening holes422corresponding to the module lifting holes132.

Since the busbar cover400is configured to wrap around the entire busbar500, the busbar500) is assembled to the module housing110in the order of seating the busbar500on the lower busbar cover410, fixing the busbar500to the high-voltage terminal120through the connection hole412of the lower busbar cover410, and then coupling the upper busbar cover420. In this regard, it may be desirable from an assembly standpoint to configure the lower busbar cover410and the upper busbar cover420to be coupled to each other in a one-touch manner by means of a hook414structure.

FIG.8is a drawing illustrating a battery module100including a thermal barrier200and a busbar cover400, andFIG.9is a cross-sectional view cut through line “A-A” inFIG.8. The busbar cover400is coupled to a pair of high-voltage terminals120one by one, and extends to a length that can be connected to the high-voltage terminals120of an adjacent battery module100. In addition, the thermal barrier200then couples over the busbar cover400to wrap around it. By this double covering of the high-voltage terminals120, the outward discharge of the ejecta is further prevented for the battery module100experiencing thermal runaway, and the inflow of the ejecta is further inhibited for other neighboring battery modules100.

And, in the second embodiment, the fixation of the busbar cover400and the thermal barrier200is done simultaneously. In other words, both the busbar cover400and the thermal barrier200are fixed together for the same module lifting hole132of the module housing110. Referring toFIG.9, the fastening member300is fastened to the module lifting hole132through the fastening hole210of the thermal barrier200and the cover fastening hole422of the busbar cover400. Since the busbar cover400and the thermal barrier200can be fixed at once with a single fastening member300, the assembly process is improved and the number of parts is reduced, which helps to improve cost.

Furthermore, in the busbar cover400, the storing space of the busbar500and the fixing position of the busbar cover400are separated from each other. That is, the cover fastening hole422of the upper busbar cover420is not connected to the storing space of the busbar500, thereby ensuring sealing of the high-voltage terminal120.

The fastening member300in the second embodiment, as in the first embodiment, may be a nut310inserted into the interior of the module lifting rib130, a bolt314screwed into the nut310through the fastening hole210, the cover fastening hole422, and the module lifting hole132, or a rivet320installed through the fastening hole210, the cover fastening hole422, and the module lifting hole132. However, with the upper busbar cover420interposed between the thermal barrier200and the module lifting holes132, there is less need for additional washers312to prevent loosening of the screws. It is also possible to apply heat-resistant silicone330to the contact surface of the thermal barrier200and the module housing110for additional assembly rigidity of the thermal barrier200.

FIG.10is a drawing illustrating another exemplary embodiment of the thermal barrier200. Referring toFIG.10, rivet320as a fastening member300and heat-resistant silicone330for additional assembly rigidity are shown. Further, the thermal barrier200shown inFIGS.7through10has a concave stepped surface220formed around the fastening hole210. The stepped surface220of the thermal barrier200may be sized to correspond to the step that the module lifting ribs130make with respect to the upper surface of the module housing110. Such a stepped surface220of the thermal barrier200may reduce the gap between the thermal barrier200and the high-voltage terminal120, which may improve the protection around the high-voltage terminal120.

The present invention has been described in more detail above with reference to the drawings and embodiments. However, it is to be understood that the configurations shown in the drawings or embodiments described herein are only one embodiment of the invention and do not represent all of the technical ideas of the invention, and that there may be various equivalents and modifications that may replace them at the time of filing the present application.

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