Patent Publication Number: US-2022231355-A1

Title: Battery Module And Battery Pack Including The Same

Description:
CROSS CITATION WITH RELATED APPLICATION(S) 
     This application claims the benefit of Korean Patent Application No. 10-2020-0051167 filed on Apr. 28, 2020 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its 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 having improved cooling performance and a battery pack including the same 
     BACKGROUND ART 
     As technology development and demands for mobile devices increase, the demand for secondary batteries as energy sources is rapidly increasing. In particular, a secondary battery has attracted considerable attention as an energy source for power-driven devices, such as an electric bicycle, an electric vehicle, and a hybrid electric vehicle, as well as an energy source for mobile devices, such as a mobile phone, a digital camera, a laptop computer and a wearable device. 
     Small-sized mobile devices use one or several battery cells for each device, whereas middle or large-sized devices such as vehicles require high power and large capacity. Therefore, a middle or large-sized battery module in which a large number of battery cells are electrically connected is used. Preferably, the middle or large-sized battery module is manufactured so as to have as small a size and weight as possible. For this reason, a prismatic battery, a pouch-type battery or the like, which can be stacked with high integration and has a small weight to capacity ratio, is usually used as a battery cell of the middle or large-sized battery module. Therefore, a middle or large-sized battery module in which a large number of battery cells are electrically connected is used, and there is an increasing need to install more battery cells in the battery module gradually. 
     Further, when the temperature of the secondary battery is higher than an appropriate temperature, the performance of the secondary battery may be deteriorated, and if it is severe, there is also a risk of an explosion or ignition. In particular, a large number of secondary batteries, that is, a battery module or a battery pack having battery cells, can add up the heat generated from the large number of battery cells in a narrow space, so that the temperature can rise more quickly and severely. In the case of a battery module in which a large number of battery cells are stacked and a battery pack equipped with such a battery module, high output can be obtained, but it is not easy to remove heat generated from the battery cells in charging and discharging operations. When the heat dissipation of the battery cell is not properly performed, deterioration of the battery cells is accelerated, the lifespan is shortened, and the possibility of explosion or ignition increases. 
     Moreover, in the case of a middle or large-sized battery module included in a vehicle battery pack, it is frequently exposed to direct sunlight and can be subjected to high temperature conditions such as summer or desert areas. 
     In addition, as the necessity for battery modules to include more battery cells increases, it is considered very important to ensure stable and effective cooling performance in relation to the heat dissipation of the battery module. 
       FIG. 1  is a perspective view of a conventional battery module.  FIG. 2  is a cross-sectional view taken along the cutting line A-A′ of  FIG. 1 . In particular,  FIG. 2  additionally shows a heat transfer member and a heat sink located under the battery module. 
     Referring to  FIGS. 1 and 2 , the conventional battery module  10  is configured such that a plurality of battery cells  11  are stacked to form a battery cell stack  20 , and the battery cell stack  20  is housed in the module frame  30 . 
     As described above, since the battery module  10  includes a plurality of battery cells  11 , it generates a large amount of heat in the charging and discharging process. The battery module  10  may include, as a cooling means, a thermally conductive resin layer  40  located between the battery cell stack  20  and the bottom part  31  of the module frame  30 . Further, when the battery module  10  is mounted on a pack frame to form a battery pack, a heat transfer member  50  and a heat sink  60  may be sequentially located under the battery module  10 . The heat transfer member  50  may be a heat dissipation pad, and the heat sink  60  may have a refrigerant flow passage formed therein. 
       FIG. 3  is an enlarged view showing an area A 1  of  FIG. 2 . Referring to  FIGS. 1 to 3 , heat generated from the battery cells  11  passes through a thermally conductive resin layer  40 , a bottom part  31  of a module frame  30 , a heat transfer member  50 , and a heat sink  60  in this order along the direction D, and then is transferred to the outside of the battery module  10 . However, as described above, the conventional battery module  10  has a complicated heat transfer path and thus, it is difficult to effectively transfer heat generated from the battery cells  11  to the outside. In particular, the module frame  30  itself can reduce the heat conducting characteristics, and a fine air layer such as an air gap that may be formed between the module frame  30 , the heat transfer member  50 , and the heat sink  60  may also reduce heat conducting characteristics. 
     Therefore, in response to the trend that demands for increasing the capacity for a battery module is continuing, it is practically necessary to develop a battery module that can satisfy these various requirements together while improving cooling performance. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Technical Problem 
     It is an object of the present disclosure to provide a battery module with a simplified cooling structure and improved cooling performance, and a battery pack including the same. 
     The objects of the present disclosure are not limited to the aforementioned objects, and other objects which are not described herein should be clearly understood by those skilled in the art from the following detailed description and the accompanying drawings. 
     Technical Solution 
     According to one 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 module frame for housing the battery cell stack; and a first heat sink located at the upper part of the module frame, wherein the first heat sink comprises an upper plate and a lower plate, wherein a lower plate of the first heat sink constitutes an upper cover of the module frame, and wherein the first heat sink forms a cooling flow passage as at least one partition wall is formed between the upper plate and the upper cover of the module frame. 
     Heat generated in the battery cell stack may be transferred in a first direction, with the first direction corresponding to each direction toward the first heat sink with reference to the center of the battery cell. 
     A refrigerant flowing through the cooling flow passage of the first heat sink may make contact with the upper cover of the module frame. 
     The partition wall may be protruded from the upper plate in a direction opposite to a direction toward the upper part of the module frame. 
     The partition wall may be extended from the upper plate to an upper part of the module frame. 
     The partition wall may have a thickness narrower than the width of the cooling flow passage. 
     The first cooling flow passage may have the same width, and an injection port and a discharge port of the first cooling flow passage may be located on the same side of the upper part of the module frame. 
     The first heat sink includes a first protrusion and a second protrusion that are located separately from each other on one side of the upper plate, and an auxiliary plate extending from end parts of the first protrusion and the second protrusion toward the module frame may be located at the lower part of the first protrusion and the second protrusion. 
     A first through part penetrating toward the upper plate is located on an auxiliary plate located at the lower part of the first protrusion, and a second through part penetrating toward the upper plate may be located on an auxiliary plate located at the lower part of the second protrusion. 
     One of the first through part and the second through part is an inflow port for injecting a refrigerant into the inside of the first heat sink, and the other one may be a discharge port for discharging the refrigerant from the inside of the first heat sink. 
     At least one of the inflow port and the discharge port may include a sealing member that wraps the outer periphery thereof. 
     A thermally conductive resin layer is formed between the lower part of the module frame and the battery cell stack, a heat transfer member and a second heat sink are sequentially formed in the lower part of the module frame, and a refrigerant flow passage is formed in the inside of the second heat sink. 
     Heat generated in the battery cell stack may be transferred in a second direction, with the second direction corresponding to each direction toward the second heat sink with reference to the center of the battery cell, and heat transferred in the first direction may be greater than heat transferred in the second direction. 
     In addition, a battery module can be provided in which the heat transfer member is a heat dissipation pad. 
     According to another embodiment of the present disclosure, there can be provided a battery pack including the above-mentioned battery module. 
     Advantageous Effects 
     According to the embodiments of the present disclosure, a battery module that improves the cooling performance while simplifying a cooling structure can be provided due to a structure in which a module frame and a heat sink are integrated. 
     In addition, the heat transfer path through which heat generated from the battery cells is transferred to the outside is simplified, thereby increasing the cooling efficiency of the battery module. 
     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 a perspective view of a conventional battery module. 
         FIG. 2  is a cross-sectional view taken along the cutting line A-A′ of  FIG. 1 . 
         FIG. 3  is an enlarged view showing an area A 1  of  FIG. 2 . 
         FIG. 4  is an exploded perspective view showing a battery module according to an embodiment of the present disclosure. 
         FIG. 5  is a perspective view showing a state in which components constituting the battery module of  FIG. 4  are coupled together. 
         FIG. 6  is an enlarged view showing an area B 1  of  FIG. 5 . 
         FIG. 7  is a cross-sectional view taken along the cutting line C-C′ of  FIG. 6 . 
         FIG. 8  is a cross-sectional view of a battery module according to another embodiment of the present disclosure, taken along the cutting line B-B′ of  FIG. 5 . 
         FIG. 9  is an enlarged view showing an area B 2  of  FIG. 8 . 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Hereinafter, various embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out them. The present disclosure may be modified in various different ways, and is not limited to the embodiments set forth herein. 
     Portions that are irrelevant to the description will be omitted to clearly describe the present disclosure, and like reference numerals designate like elements throughout the specification. 
     Further, in the figures, the size and thickness of each element are arbitrarily illustrated for convenience of description, and the present disclosure is not necessarily limited to those illustrated in the figures. In the figures, the thickness of layers, areas, etc. are exaggerated for clarity. In the figures, for convenience of description, the thicknesses of some layers and areas are shown to be exaggerated. 
     Further, throughout the specification, when a portion is referred to as “including” a certain component, it means that the portion can further include other components, without excluding the other components, unless otherwise stated. 
     Further, throughout the specification, when referred to as “planar”, it means when a target portion is viewed from the upper side, and when referred to as “cross-sectional”, it means when a target portion is viewed from the side of a cross section cut vertically. 
     In the following, the battery pack for a secondary battery according to an embodiment of the present disclosure will be described. However, the description herein is made based on the front surface of the front and rear surfaces of the battery pack, but is not necessarily limited thereto, and even in the case of the rear surface, the same or similar contents may be described. 
     In the following, the battery module according to an embodiment of the present disclosure will be described. However, the description herein is made based on the front surface of the front and rear surfaces of the battery module, without being limited thereto, and even in the case of the rear surface, the same or similar contents may be described. 
       FIG. 4  is an exploded perspective view showing a battery module according to an embodiment of the present disclosure.  FIG. 5  is a perspective view showing a state in which components constituting the battery module of  FIG. 4  are coupled together. 
     Referring to  FIGS. 4 and 5 , the battery module  100  according to an embodiment of the present disclosure includes a battery cell stack  200  in which a plurality of battery cells  110  are stacked, a module frame  300  in which the battery cell stack  200  is disposed, a first heat sink  700  located at the upper part of the module frame  300 , and end plates  800  that cover the front and rear surfaces of the battery cell stack  200 . 
     As an example, the module frame  300  includes a U-shaped frame of which an upper surface, a front surface and a rear surface are opened, and an upper plate  400  that covers the upper part of the battery cell stack  120 . The U-shaped frame  320  includes a bottom part  321  located in the direction in which the battery cell stack  200  is inserted, and side parts  322  that wrap both side surfaces of the battery cell stack  200  at both sides of the bottom part  321 . However, the module frame  300  is not limited thereto, and can be replaced with a frame having another shape such as a mono frame surrounding the battery cell stack  200 , except for the L-shaped frame or the front and rear surfaces. 
     The first heat sink  700  according to the present embodiment includes an upper plate  710  on which a recessed part  715  is formed, and a lower plate  310  coupled to the upper plate  710 . In this case, the lower plate  310  of the first heat sink  700  may constitute the upper cover  310  of the module frame  300 . In the following, the lower plate  310  of the first heat sink  700  and the upper cover  310  of the module frame  300  will be described as the same configuration. 
     As the first heat sink  700  forms at least one partition wall  720  between the upper plate  710  and the lower plate  310 , it may form a cooling flow passage through which refrigerant flows. The partition wall  720  corresponds to a structure that is formed by the recessed part  715  formed in the upper plate  710 , and the recessed part  715  may be formed in the upper plate  710  in a direction away from the lower plate  310 . 
     The module frame  300  includes a U-shaped frame  320  of which an upper surface, a front surface and a rear surface are opened, and an upper cover  310  that covers the upper part of the battery cell stack  200 . However, the module frame  300  is not limited thereto, and can be replaced with a frame having another shape such as a mono frame surrounding the battery cell stack  200 , except for the L-shaped frame or the front and rear surfaces. 
     The battery cell  110  is preferably a pouch-type battery cell. The battery cell can be manufactured by housing the electrode assembly in a pouch case of a laminate sheet including a resin layer and a metal layer, and then heat-sealing the sealing part of the pouch case. Such a battery cell  110  may be composed of a plurality of cells, and the plurality of battery cells  110  form a battery cell stack  200  that is stacked so as to be electrically connected to each other. In particular, as shown in  FIG. 4 , a plurality of battery cells  110  may be stacked along a direction parallel to the x-axis. 
     However, the battery module  100  according to an embodiment of the present disclosure may be a large area module in which the battery cell stack  120  includes a relatively larger number of battery cells than the conventional battery module. In the case of a large area module, the length of the battery module in the horizontal direction becomes relatively long. Here, the length of the battery module in the horizontal direction may mean the length in the direction in which the battery cells are stacked. Therefore, when the battery module  100  corresponds to a large area module, as the number of battery cells  100  contained in the battery cell stack  200  increases, the heat generated may also increase. To this end, the battery module  100  needs to be more improved in the cooling performance. 
     The first heat sink  700  included in the battery module  100  according to the present embodiment is located at the upper part of the module frame  300 . As the upper cover  310  of the module frame  300  constitutes the lower plate of the first heat sink  700 , the refrigerant flowing through the cooling flow passage of the first heat sink  700  may make contact with the upper cover  310  of the module frame  300 . Thereby, heat generated in the battery cell  110  is rapidly cooled by the refrigerant in contact with the upper part of the module frame  300  and thus, the cooling efficiency can be improved. In addition, unlike the conventional battery module  10 , unnecessary cooling structures can be eliminated and thus, the height of the battery module  100  is reduced, thereby reducing costs and increasing space utilization. 
     In particular, when a sealing part (not shown) of the battery cell  110  is located at the upper end part of the battery cell stack  200 , there is a possibility that flames or the like may be discharged from the sealing part. Thereby, heat generation may be relatively severe at the upper end part of the battery cell stack  200 . However, according to the present embodiment, as the first heat sink  700  is disposed adjacent to the upper end part of the battery cell stack  200 , the cooling efficiency can be further increased 
     The first heat sink  700  may be connected to at least a partial area of the upper cover  310  of the module frame  300  through a process such as heat fusion or welding. In particular, the upper plate  710  of the first heat sink  700  may be directly coupled to the area in contact with the upper cover  310  of the module frame  300  through a process such as thermal welding or welding. 
     Accordingly, the refrigerant flowing through the recessed part  715  formed in the inside of the first heat sink  700  can flow without leaking to the outside. 
     The recessed part  715  formed in the first heat sink  700  is a part in which the upper plate  710  is formed so as to be protruded upward, and the recessed part  715  may form a meandering cooling flow passage in the upper plate  710 . Therefore, a partition wall  720  may be formed between the adjacent recessed parts  715 . The recessed part  715  may be a U-shaped tube having a cross-section cut in the yz plane perpendicular to the direction in which the refrigerant flows, and the upper cover  310  of the module frame  300  may be located at the opened lower side of the U-shaped tube. 
     As the first heat sink  700  is formed with at least one partition wall  720  between the upper plate  710  and the upper cover  310  of the module frame, a cooling flow passage corresponding to the recessed part  715  may be formed. Here, the partition wall  720  may have a shape protruding from the upper plate  710  toward the upper cover  310  of the module frame  300 . The partition wall  720  may be directly coupled to the upper cover  310  of the module frame  300 . In particular, one area of the partition wall  720  that is directly coupled to the upper cover  310  of the module frame  300  can be connected to at least a partial area of the upper cover  310  of the module frame  300  through a process such as heat fusion or welding. Accordingly, the refrigerant may flow through a cooling flow passage formed along the partition wall  720  in the inside of the first heat sink  700 . 
     Further, the partition wall  720  may have a thickness narrower than the width of the recessed part  715 . In order to expand the recessed part  715 , which is a space in which a cooling flow passage is formed, to the maximum, the partition wall  720  may have a thickness minimized enough to be directly coupled to the upper cover  310  of the module frame  300 . Accordingly, the amount of the refrigerant contained in the first heat sink  700  can be maximized and thus, the cooling efficiency for heat generated from the battery cells  110  can be improved. 
     It is more preferable that the recessed part  715  has a shape in which the cooling flow passage is bent several times in the first heat sink  700  in order to reduce the temperature deviation between the widths of the refrigerant flow passages. 
     Hereinafter, the configuration of the first heat sink  700  according to an embodiment of the present disclosure will be described in more detail. 
       FIG. 6  is an enlarged view showing an area B 1  of  FIG. 5 .  FIG. 7  is a cross-sectional view taken along the cutting line C-C′ of  FIG. 6 . 
     Referring to  FIGS. 6 and 7 , a first heat sink  700  contained in the battery module  100  according to an embodiment of the present disclosure may include not only an upper plate  710 , a partition wall  720  formed to be extended from the upper plate  710 , and a recessed part  715  partitioned by the partition wall  720 , but also a first protrusion  740  and a second protrusion  745  formed on one side of the first heat sink  700 . In particular, the first protrusion  740  and the second protrusion  745  may be located on one side adjacent to the upper cover  310  of the module frame  300 . 
     The first protrusion  740  and the second protrusion  745  are the areas formed by extending the upper plate  710  and extending in the y-axis direction beyond the upper cover  310  of the module frame  300 . As an example, an auxiliary plate  730  can be directly coupled to the lower part of each of the first protrusion  740  and the second protrusion  745  through a process such as heat fusion or welding. 
     The auxiliary plate  730  may include a through part  730 P in at least a partial area. The through part  730 P is an area that is passed through the auxiliary plate  730  so as to face the upper plate  710 . That is, the through part  730 P may be a hole that allows a partial region of the recessed part  715  to be opened. The through part  730 P may include a first through part  740 P and a second through part  745 P. A first through part  740 P is formed in the first protrusion  740 , and a second through part may be formed in the second through part  745 P. The through part  740 P may be an inflow port that supplies the refrigerant from the outside to the inside of the first heat sink  700  or a discharge port for allowing the refrigerant flowing inside the first heat sink  700  to be discharged to the outside of the first heat sink  700 . As an example, when the first through part  740 P formed in the first protrusion  740  is an inflow port, the second through part  745 P formed in the second protrusion  745  may be a discharge portion, and vice versa. 
     Further, as shown in  FIG. 7 , the through part  730 P may include a sealing member  750  surrounding the outer periphery thereof. As the sealing member  750  is formed on the outer periphery of the through part  730 P, leakage of the refrigerant at the time of inflow and discharge of the refrigerant can be prevented. Further, the structure of the sealing member  750  according to the present embodiment is not limited, but a gasket-shaped member or a valve port member may be applied. 
     In addition, the through part  730 P can be connected to a separate cooling port (not shown) through which refrigerant is supplied and discharged to the heat sink. Here, the cooling port (not shown) may include a refrigerant injection port and a refrigerant discharge port. As an example, when the first through part  740 P is an inflow port, the refrigerant injection port is connected, and when the second through part  745 P is a discharge port, a refrigerant discharge port may be connected. 
       FIG. 8  is a cross-sectional view of a battery module according to another embodiment of the present disclosure, taken along the cutting line B-B′ of  FIG. 5 .  FIG. 9  is an enlarged view showing an area B 2  of  FIG. 8 . In particular, the battery module  100  according to the embodiment of  FIGS. 8 and 9  may further include a heat transfer member  500  and a second heat sink  600  located under the battery module  100 . 
     As described above, since the battery module  100  includes a plurality of battery cells  110 , a large amount of heat is generated in the charging and discharging process. In particular, in order to form a large-area module, by mounting a battery cell stack including more battery cells in one battery module compared to the existing battery module, the battery module  100  can generate a greater amount of heat compared to the conventional battery module  10 . The battery module  100  may include, as a cooling means, a first heat sink  700  located on the upper part  310  of the module frame  300 . 
     Referring to  FIGS. 8 and 9 , heat generated from the battery cell  110  passes through the upper part  310  of the module frame  300  and the refrigerant included in the first heat sink  700  in this order along the first direction D 1 , and can be transferred to the outside of the battery module  100 . Here, the first direction D 1  may be a direction corresponding to a direction toward the first heat sink  700  with reference to the center of the battery cell  110 . Therefore, a conventional unnecessary cooling structure is eliminated, the heat transfer path is simplified, and an air gap between layers may be reduced, so that cooling efficiency or performance can be increased. In particular, when compared to the conventional heat sink  60  of  FIGS. 1 and 2 , the refrigerant contained in the first heat sink  700  makes contact with the upper part  310  of the module frame  300 , thereby capable of performing more direct cooling. 
     Further, the lower part  310  of the module frame  300  is required to have a separate layer for fixing the battery cell stack or securing the insulation performance, whereas the upper part  310  of the module frame  300  is in direct contact with the upper part of the battery cell stack  200 . Therefore, when the first heat sink  700  is located on the upper part  310  of the module frame  300  rather than the first heat sink  700  is located on the lower part  321  of the module frame  300 , it may be more effective in carrying out direct cooling with the refrigerant. 
     According to another embodiment of the present disclosure, the battery module  100  may include, as an auxiliary cooling means together with the first heat sink  700 , a thermally conductive resin layer  400  located between the battery cell stack  200  and the bottom part  321  of the module frame  300 . Further, when the battery module  100  is mounted on the pack frame to form a battery pack, a heat transfer member  500  and a heat sink  600  may be sequentially located under the battery module  100 . The heat transfer member  500  may be a heat dissipation pad, and a refrigerant flow passage may be formed in the heat sink  600 . 
     Referring to  FIGS. 8 and 9 , at least a part of the heat generated from the battery cells  110  passes through the thermally conductive resin layer  400 , the bottom part  321  of the module frame  300 , the heat transfer member  500 , and the second heat sink  600  in this order along the second direction D 2 , and can be transferred to the outside of the battery module  100 . Here, the second direction D 2  may be a direction corresponding to a direction toward the second heat sink  600  with reference to the center of the battery cell  110 . The heat transfer passage through the second heat sink  600  is more complicated than that of the first heat sink  700 , but cooling may be supplementally performed on heat generated as the battery module  100  forms a large-area module. That is, heat transferred in the first direction D 1  may be greater than heat transferred in the second direction D 2 . 
     Accordingly, in the battery module  100 , heat generated from the battery cells  110  is mainly transferred in the first direction D 1  toward the first heat sink  700 , directly cooled, and supplementarily transferred in the second direction (D 2 ) and cooled through the second heat sink  600 , so that the cooling performance can be further improved and the problem of heat generation can be controlled in detail. In addition, as heat generated from the battery cell  110  is dispersed and cooled in the first direction (D 1 ) and the second direction (D 2 ), the temperature deviation of the battery cell stack  200  may be reduced compared to the conventional one. 
     The one or more battery modules according to the present embodiment described above can be mounted together with various control and protection systems such as a battery management system (BMS) and a cooling system to form a battery pack. 
     The above-mentioned battery module or the battery pack can be applied to various devices. These devices may be applied to transportation means such as an electric bicycle, an electric vehicle, a hybrid vehicle, but the present disclosure is not limited thereto and can be applied to various devices that can use the battery module or the battery pack including the same. 
     Although the preferred embodiments of the present disclosure have been described in detail above, the scope of the present disclosure is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present disclosure defined in the following claims also belong to the scope of rights. 
     DESCRIPTION OF REFERENCE NUMERALS 
     
         
         
           
               100 : battery module 
               110 : battery cell 
               120 : battery cell stack 
               130 : busbar frame 
               140 : protective frame 
               200 : module frame