Patent Publication Number: US-2023155231-A1

Title: Battery module and battery pack including the same

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a US national phase of international Application No. PCT/KR2021/008943 filed on Jul. 13, 2021, and claims the benefit of Korean Patent Application No. 10-2020-0102382 filed on Aug. 14, 2020 with the Korean Intellectual Property Office, the disclosures of which are incorporated herein by reference in their entirety. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to a battery module and a battery pack including the same, and more particularly, to a battery module including a structure for preventing penetration of moisture, and a battery pack including the same. 
     BACKGROUND ART 
     A secondary battery has attracted much attention as an energy source in various products such as a mobile device and an electric vehicle. The secondary battery is a potent energy resource that can replace the use of existing products that consume fossil fuels, and is in the spotlight as an environment-friendly energy source because it does not generate by-products due to energy use. 
     Recently, along with a continuous rise in demand for a large-capacity secondary battery structure, including the utilization of the secondary battery as an energy storage source, there is a growing demand for a battery pack of a multi-module structure which is an assembly of battery modules in which a plurality of secondary batteries are connected in series/parallel. 
     Meanwhile, when a plurality of battery cells are connected in series/parallel to form a battery pack, a common method of manufacturing a battery pack includes manufacturing a battery module composed of at least one battery cell and then adding other components to the at least one battery module. 
     Such a battery module may include a battery cell stack in which a plurality of battery cells are stacked, a housing for accommodating the battery cell stack, and a busbar frame for covering the front and rear surfaces of the battery cell stack and equipped with a busbar. 
       FIG.  1    is illustrates a moisture inflow route of a conventional battery module. 
     As illustrated in  FIG.  1   , a conventional battery module includes a battery cell stack  10  in which a plurality of battery cells are stacked, a housing for covering the battery cell stack  10 , a busbar frame  30  for covering the front and rear surfaces of the battery cell stack  10 , an insulating cover  70  for covering the outer side surface of the busbar frame  30 , and an end plate  80  for covering the outer side surface of the insulating cover. 
     A connector  50  coupled with a flexible flat cable (FFC)  40  can be formed on the outer side portion of the busbar frame  30 . More specifically, a busbar frame  30  is formed on the front and rear surfaces of the battery cell stack  10 , respectively, a connector  50  is formed on the outer side surface of each busbar frame  30 , and the FFC  40  is formed in the upper side space of the battery cell stack  10 , so that the connectors  50  formed on the two busbar frames  30  can be connected with each other. 
     During the assembly process of the FFC, a robot arm equipment can be used to automate the battery module assembly line. Here, the robot arm grasps the FFC and assembles it in a vertical direction toward the upper surface portion of the battery cell stack. The FFC, which has moved downward in the vertical direction, can be combined with the connector located at both ends of the battery cell stack. An upper portion of the connector coupled with the FFC moving vertically downward may have an open form. 
     When the inside of the battery module is placed in a high temperature and high humidity environment, condensed moisture may be formed on the lower side surface of the upper portion  21  of the housing, and moisture moving along the lower side surface of the upper portion  21  may flow into the inside of the connector  50  through the FFC or may directly flow into the inside of the connector  50 . 
     When moisture flows into the inside of the connector, a short circuit may occur at the connection part between the connector  50  and the FFC  40 , damaging the sensing function of the connector and the FFC, and causing an ignition phenomenon inside the battery module. 
     SUMMARY 
     It is an objective of the present disclosure to provide a battery module including a structure that allows the moisture inside the battery module to be safely discharged to the outside. 
     The objective of the present disclosure is not limited to the aforementioned objective, and other objectives which are not described herein should be clearly understood by those skilled in the art from the following detailed description. 
     In order to achieve the above objective, according to one exemplary embodiment of the present disclosure, there is provided a battery module comprising: a battery cell stack in which a plurality of battery cells are stacked; a housing for accommodating the battery cell stack; busbar frames formed at both ends of the battery cell stack; a connecting portion that connects the busbar frames arranged at both ends, and is formed of a flexible flat cable (FFC); and a connector formed on the busbar frame and coupled to the connecting portion, wherein a film portion is formed between the connector and the upper side portion of the housing. 
     The battery further includes an insulating cover for covering the outside of the busbar frame; and an end plate for covering the outside of the insulating cover, wherein the film portion may guide the moisture that flows inside to a passage formed between the end plate and the insulating cover. 
     The insulating cover may include an extension portion formed on the lower side of the film portion. 
     The extension portion may be formed to be inclined downward in a direction in which the end plate is located. 
     The tip end of the extension portion may be formed to be curved upward. 
     A crack between the upper portion of the housing and the end plate may be connected with the extension portion. 
     The passage may be connected with the outside of the housing, and moisture guided to the passage may be discharged to the outside of the housing through the passage. 
     The film portion may be formed in a size corresponding to the upper portion of the housing. 
     The film portion may be coupled with both edge portions of the upper portion of the housing by an adhesive member, respectively, and a moisture moving passage may be formed in the space formed between the adhesive members. 
     The film portion may be formed of a polycarbonate sheet. 
     According to another exemplary embodiment of the present disclosure, there is provided a battery pack comprising the above-mentioned battery module. 
     A battery module and a battery pack including the same according to one exemplary embodiment of the present disclosure can discharge moisture formed on the lower surface of the upper side portion to the outside through a moisture barrier film between the connector and the upper portion of the housing. 
     The effects of the present disclosure are not limited to the effects mentioned above and additional other effects not described above will be clearly understood from the description of the appended claims by those skilled in the art. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is an illustration of a moisture inflow route of a conventional battery module; 
         FIG.  2    is an exploded perspective view of a battery module according to one exemplary embodiment of the present disclosure; 
         FIG.  3    is an illustrated of the battery module of  FIG.  2    after it has been assembled; 
         FIG.  4    is a cross-sectional view along a section A-A′ of  FIG.  3   ; and 
         FIG.  5    is a partial view showing the direction in which moisture moves through the moisture barrier film. 
     
    
    
     DETAILED DESCRIPTION 
     It should be appreciated that the exemplary embodiments, which will be described below, are illustrative to assist in the understand the present disclosure, and the present disclosure can be variously modified to be carried out differently from the exemplary embodiments described herein. However, in the description of the present disclosure, the specific descriptions and illustrations of publicly known functions or constituent elements will be omitted when it is determined that the specific descriptions and illustrations may unnecessarily obscure the subject matter of the present disclosure. In addition, in order to help understand the present disclosure, the accompanying drawings are not illustrated based on actual scales, but parts of the constituent elements may be exaggerated in size. 
     As used herein, terms such as first, second, and the like may be used to describe various components, and the components are not limited by the terms. The terms are used only to discriminate one component from another component. 
     Further, the terms used herein are used only to describe specific exemplary embodiments, and are not intended to limit the scope of the present disclosure. A singular expression includes a plural expression unless they have definitely opposite meanings in the context. It should be understood that the terms “comprise”, “include”, and “have” as used herein are intended to designate the presence of stated features, numbers, steps, movements, constitutional elements, parts or combinations thereof, but it should be understood that they do not preclude a possibility of existence or addition of one or more other features, numbers, steps, movements, constitutional elements, parts or combinations thereof. 
     A battery module according to one exemplary embodiment of the present disclosure will be described with reference to  FIGS.  2  and  3   . 
       FIG.  2    is an exploded perspective view of a battery module according to one exemplary embodiment of the present disclosure.  FIG.  3    is an illustration of the battery module of  FIG.  2    after it has been assembled. 
     As illustrated in  FIGS.  2  and  3   , the battery module according to one exemplary embodiment of the present disclosure includes a battery cell stack  100  in which a plurality of battery cells are stacked, a housing  200  for accommodating the battery cell stack  100 ; and a busbar frame  300  formed at both ends of the battery cell stack  100 . The battery module also includes a connecting portion  400  that connects the busbar frames  300  arranged at both ends, respectively, and is formed of a flexible flat cable (FFC), and a connector  500  formed on the busbar frame  300  and coupled with the connecting portion  400 . A film portion  600  is formed between the connector  500  and the upper portion  210  of the housing  200 . 
     The battery cell is a secondary battery and can be configured into a pouch-type secondary battery. Such a battery cell may include a plurality of cells, and the plurality of battery cells may be stacked together to be electrically connected with each other, thereby forming the battery cell stack  100 . Each of the plurality of battery cells may include an electrode assembly, a cell case, and an electrode lead protruding from the electrode assembly. 
     The housing  200  accommodates the battery cell stack  100 . The housing  200  can be formed of a U-shaped frame  200  and an upper portion  210  as shown in  FIG.  2   . The U-shaped frame  200  may include a bottom portion and both side portions. Although not illustrated in  FIG.  2   , the housing  200  can be formed of upper, lower, left and right portions to cover the upper, lower, left and right surfaces, respectively, of the battery cell stack  100 . The battery cell stack  100  accommodated inside the housing  200  can be physically protected through the housing  200 . 
     The busbar frame  300  is formed to cover the front and rear surfaces of the battery cell stack  100 , is located on the front and rear surfaces of the battery cell stack  100 , and can be connected with electrode leads that extend from the plurality of battery cells. In more detail, electrode leads extending through the busbar frame  300  are coupled to the plurality of busbars mounted on the busbar frame  300 , to electrically connect the battery cells and the busbar. 
     End plate  800  is formed on the outside of the busbar frame  300  of the battery cell stack  100 , so that it can cover the battery cell stack  100  and the busbar frame  300 . 
     The end plate  800  can protect the busbar frame  300 , the battery cell stack  100 , and various electrical equipment connected thereto from external impacts, and at the same time, guide the electrical connection between the battery cell stack  100  and an external power. An insulating cover  700  can be inserted between the end plate  800  and the busbar frame  300 . The insulating cover  700  may cut off the electrical connection between the busbar frame  300  and the outside to ensure the insulation performance of the battery module. 
     A thermal conductive resin layer  900  can be formed on the bottom surface  200  of the housing bottom. The battery cell stack  100  is located on the upper side of the thermal conductive resin layer  900 , and heat generated from the battery cell stack  100  can be transferred to the outside of the battery module. According to this exemplary embodiment, the thermal conductive resin layer  900  may be formed of a thermal resin. 
     According to the embodiment of the present disclosure, the battery module includes a connecting portion  400  that connects the busbar frames  300  arranged at both ends, respectively, and is formed of a flexible flat cable (FFC). The connecting portion  400  may be parallel to the longitudinal direction of any one of the plurality of battery cells constituting the battery cell stack  100 . 
     Since the connecting portion  400  can be formed of a soft cable to be curved, the circuit for electrical connection between the busbar frames is inserted in the inside of the cable, thereby making it easy to cope with external impacts. 
     The connector  500  is formed on the busbar frame  300  and coupled with the connecting portion  400 . The connector  500  can sense information such as voltage and temperature of a plurality of battery cells constituting the battery cell stack  100 . The connecting portion  400  may transmit information sensed from the rear surface of the battery cell stack  100  to the connector  500  located on the front surface of the battery cell stack  100 . 
     According to the embodiment of the present disclosure, a film portion  600  is formed between the connector  500  and the upper portion  210  of the housing  200 . The film portion  600  may guide moisture formed on the lower surface of the upper portion  210  of the housing  200  to a passage formed between the insulating cover  700  and the end plate  800 . The film portion  600  may include a polycarbonate sheet. 
     Conventionally, moisture formed on the lower side of the upper portion of the housing flows into a connector having an open upper side, and may cause a short circuit inside the connector. Therefore, according to the embodiment of the present disclosure, the film portion  600  is installed between the connector  500  and the upper side portion  210  of the housing  200 , and moisture formed on the lower side of the upper portion  210  moves along the upper surface of the film portion  600 , without falling on the portion where the connector  500  is located, and immediately passes through the upper surface of the insulating cover  700 , through the passage P between the insulating cover  700  and the end plate  800 , and falls to the outside of the battery module. 
     When the battery module to which the FFC vertical assembly is applied through this moisture discharge structure is placed in environmental conditions with high temperature and high humidity, it is possible to prevent the inflow of moisture into the connector  500  and thus, protect the sensing function of the battery module. 
     A battery module in which a film portion is formed in accordance with one exemplary embodiment of the present disclosure will be described with reference to  FIGS.  2 ,  4  and  5   . 
       FIG.  4    is a cross-sectional view of a section A-A′ of  FIG.  3   .  FIG.  5    is a partial view showing the direction in which moisture moves through the moisture barrier film. 
     According to the embodiment of the present disclosure, the insulating cover  700  may include an extension portion  710  that protrudes from the lower side of the film portion  600 . Therefore, moisture flowing along the upper surface of the film portion  600  may fall to the upper surface of the insulating cover  700  without falling to the portion where the connector  500  is located. The extension portion  710  may be formed to be inclined in a direction in which the end plate  800  is located. The tip end of the extension portion  710  is formed to be curved upward, and the upper surface of the extension portion  710  may be formed in an inclined manner. Therefore, it is possible to prevent moisture from falling on the upper surface of the insulating cover  700  from flowing in a reverse direction toward the tip end of the extension portion  710  and falling on the connector  500 . 
     Moisture that has fallen on the upper side of the insulating cover  700  can move in the direction in which the end plate  800  is located along the inclined upper surface of the insulating cover  700 . A passage P may be formed between the end plate  800  and the insulating cover  700 . Moisture guided in the direction in which the end plate  800  is located can be discharged to the outside of the housing  200  through the passage P formed between the end plate  800  and the insulating cover  700 . 
     Further, according to the embodiment of the present disclosure, a crack C may be formed between the upper side portion  210  of the housing  200  and the end plate  800 . The crack C may be connected with the upper surface of the insulating cover  700  and the upper surface of the extension portion  710 . In some cases, moisture may flow in from the outside of the battery module. In such a case, moisture may flow into the crack C between the end plate  800  and the housing  200  at the upper side of the battery module. Even in this case, the moisture flowing into the device is guided to the upper surface of the insulating cover  700 , and the moisture thus guided may be discharged to the outside of the housing  200  through the passage P formed between the end plate  800  and the insulating cover  700 . 
     The film portion  600  may have a size corresponding to the upper portion  210  of the housing. In this case, both edge portions  210   a  and  210   b  of the upper portion  210  of the housing and the film portion  600  may be coupled to each other by an adhesive member  610 . Further, as illustrated in  FIG.  5   , a moisture moving passage may be formed in a space formed between the adhesive members  610 . According to this embodiment, the adhesive member  610  may be formed of a double-sided tape. 
     The film portion  600  formed of a thin film is attached to the edge portions on a lower surface of the upper portion  210  of the housing through an adhesive member  610  formed of a double-sided tape, thereby minimizing a space occupancy in the battery module due to the film portion  600  and the adhesive member  610 . 
     The above-mentioned battery module can be included in a battery pack. The battery pack may have a structure in which one or more of the battery modules according to the embodiment of the present disclosure are gathered, and packed together with a battery management system (BMS) and a cooling device that controls and manages the battery&#39;s temperature, voltage, etc. 
     The battery pack can be applied to various devices. Such a device may be applied to a vehicle means such as an electric bicycle, an electric vehicle, or a hybrid vehicle, but the present disclosure is not limited thereto, and is applicable to various devices that can use a battery module, which also falls under the scope of the present disclosure. 
     Although the invention has been shown and described with reference to the preferred embodiments, the scope of the present disclosure is not limited thereto, and numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of the invention described in the appended claims. Further, these modified embodiments should not be understood individually from the technical spirit or perspective of the present disclosure.