Patent Publication Number: US-2022231367-A1

Title: Battery Module and Battery Pack Including the Same

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a national phase entry under 35 U.S.C. § 371 of International Application No. PCT/KR2021/002927, filed on Mar. 9, 2021, published in Korean, which claims the benefit of Korean Patent Application No. 10-2020-0052262 filed on Apr. 29, 2020 with the Korean Intellectual Property Office, the disclosures of which are incorporated herein by reference in their entireties. 
     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 a partition wall structure, and a battery pack including the same. 
     BACKGROUND ART 
     As technology development and demands for mobile devices increase, the demand for 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. The middle or large-sized battery module is preferably manufactured so as to have as small a size and weight as possible. Consequently, a prismatic battery, a pouch-shaped battery or the like, which can be stacked with high integration and has a small weight relative to capacity, 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, a cell event may occur. As an example, there is also a risk of occurrence of a thermal event such as an explosion or ignition. In particular, a large number of secondary batteries, that is, a battery module or a battery pack having a battery cell, 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 as the number of battery cells increases, the possibility of explosion or ignition also 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. Consequently, when explosion or ignition occurs in the battery module, it is necessary to prevent the ignition from being transferred to another battery cell in a specific battery cell and so prevent further ignition from proceeding. 
       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 a view showing a cross-section of the battery module of  FIG. 2  in which a cell event has occurred. 
     Referring to  FIGS. 1 and 2 , the conventional battery module  10  includes a battery cell stack  12  formed by stacking a plurality of battery cells  11 , a lower frame  20  on which the battery cell stack  12  is disposed, and an upper plate  30  for covering the upper portion of the battery cell stack  12 . In addition, for the insulation of the battery cell stack  12 , the battery module  10  further includes an insulating layer  40  formed between the upper plate  30  and the battery cell stack  12 . 
     In this case, the battery module  10  may further comprise a compression pad  50  located between battery cells adjacent to each other among the plurality of battery cells  11  and between the outermost battery cells of the battery cell stack  12  and the side surface portion of the lower frame  20 . Accordingly, the compression pad  50  and the plurality of battery cells  11  may form one stack structure, and the compression pad  50  may also absorb the swelling of the battery cells  11 . However, the conventional compression pad  50  cannot block ignition or induce a direction of ignition when a cell event such as ignition occurs. 
     As an example, referring to  FIGS. 2 and 3 , the conventional battery module  10  may be partially partitioned by the compression pad  50  in the battery cell stack  12 . However, when a first cell event (cel) such as ignition occurs in a part of the plurality of battery cells, the compression pad  50  cannot block the ignition or induce the direction of ignition, so that even for some battery cells in which the first cell event (cel) has not occurred, a second cell event (ce 2 ) to which the first cell event (cel) has propagated occurs. 
     Thereby, in the conventional battery module  10 , when a cell event such as ignition occurs in some battery cells of the battery cell stack  12 , an ignition phenomenon may propagate to other battery cells included in the battery module  10 , and thus, there is a problem in that the cell event may become more serious. 
     Therefore, in the trend that a demand such as an increase in capacity for a battery module continues, 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 is to provide a battery module having a partition wall structure, 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 can be 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 partition wall portion located between the battery cell stack and the module frame, wherein the partition wall portion comprises a first partition wall member located between an upper portion of the battery cell stack and the module frame, and wherein the partition wall portion further comprises at least one second partition wall member extending in a perpendicular direction from the first partition wall member. 
     The at least one second partition wall member may extend up to a lower portion of the module frame, and the battery cell stack may be located partitioned into a first stack and a second stack by the partition wall portion. 
     The partition wall portion may block a cell event generated in the first stack from being diffused to the second stack. 
     The at least one second partition wall member may include at least two second partition wall members that may be located separately from each other so as to have equal intervals in a stacking direction of the battery cell stack. 
     The at least one second partition wall member may include at least two second partition wall members that may be located symmetrically with reference to a center of the battery cell stack. 
     The at least one second partition wall member may be located between an outermost battery cell of the plurality of battery cells and a side portion of the module frame, or may be located between battery cells adjacent to each other among the plurality of battery cells. 
     Two of the at least one second partition wall member are respectively located between outermost battery cells of the plurality of battery cells and side portions of the module frame, and one of the at least one second partition wall member is located between battery cells adjacent to each other among the plurality of battery cells. 
     The partition wall portion may be composed of a functional material having flame retardancy and insulating properties. 
     The module frame may include a U-shaped frame that houses the battery cell stack and has an opened upper portion, and an upper plate that covers the battery cell stack in the opened upper portion of the U-shaped frame. 
     The first partition wall member is located between the upper plate and the battery cell stack, and two of the at least one second partition wall member may be respectively located between outermost battery cells of the plurality of battery cells and side portions of the U-shaped frame, and one of the at least one second partition wall member may be located between battery cells adjacent to each other among the plurality of battery cells. 
     In addition, there can be provided a battery pack comprising the battery module according to one embodiment of the present disclosure. 
     Advantageous Effects 
     According to the embodiments of the present disclosure, a battery module can be provided in which the battery module includes a partition wall structure to thereby block cell events occurring in some battery cells or induce a propagation direction. 
     Effects of the present disclosure may not be limited to the above-mentioned effects, and other effects of the present disclosure will be clearly understandable to those having ordinary skill in the art from the disclosures provided below together with accompanying drawings. 
    
    
     
       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 a view showing a cross-section of the battery module of  FIG. 2  in which a cell event has occurred. 
         FIG. 4  is an exploded perspective view showing a battery module according to an embodiment of the present disclosure. 
         FIG. 5  is a partial perspective view showing a state in which the components of the battery module of  FIG. 4  are combined. 
         FIG. 6  is a perspective view showing a state in which the components constituting the battery module of  FIG. 4  are combined. 
         FIG. 7  is a cross-sectional view showing a partial area of the cross-section taken along the cutting line B-B′ of  FIG. 6 . 
         FIG. 8  is a cross-sectional view showing the battery module of  FIG. 7  in which a cell event has occurred. 
     
    
    
     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, regions, etc. are exaggerated for clarity. In the figures, for convenience of description, the thicknesses of some layers and regions 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 electrode 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 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 partial perspective view showing a state in which the components of the battery module of  FIG. 4  are combined. The partial perspective view of  FIG. 5  shows a state in which the upper plate is removed from the battery module of  FIG. 4 . 
     Referring to  FIGS. 4 and 5 , a 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  that houses the battery cell stack  200 , a partition wall portion  500  located between the battery cell stack  200  and the module frame  500 , and end plates  600  located on the front and rear surfaces of the battery cell stack  200 . 
     The module frame  300  includes a U-shaped frame  320  including a bottom portion  321  and a side portion  321 , of which an upper surface, a front surface and a rear surface are opened, and an upper plate  310  that covers an upper portion 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 portion 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. Therefore, the battery module  100  needs to prevent an additional cell event from being occurred as a cell event, that is generated in a specific battery cell among the plurality of battery cells  110 , propagates to other battery cells. 
     Here, the cell event is an emergency situation that occurs in at least one battery cell among the plurality of battery cells  110  contained in the battery module  10 , which involves leakage of a battery cell or a battery module, mechanical damage to battery cells, and occurrence of a thermal event that is ignited in response to a temperature rise, and the like. In particular, the thermal event includes the occurrence of a flame and/or a venting gas by the ignition of the battery cell. The thermal event can be particularly diffused in the inside of the battery pack including the battery module  100  and the battery module  100 . Thus, there is a risk of raising the temperature of the surrounding battery module or the battery cells  110  in the battery module  100 , thereby causing a chain of additional cell events. 
     Referring to  FIGS. 4 and 5 , the partition wall portion  500  according to an embodiment of the present disclosure includes a first partition wall member  510  located between the upper portion of the battery cell stack  200  and the module frame  300 , and includes at least one second partition wall member  520  extending in a vertical direction from the first partition wall member  510 . Here, the partition wall portion  500  may be composed of a functional material having flame retardancy and insulating properties. Consequently, the partition wall portion is excellent in insulation property and flame retardancy when a cell event occurs, and so it can prevent the cell event from becoming severe and inhibit the diffusion of cell events and induce a direction of progression. 
     The first partition wall member  510  may have a shape corresponding to the upper plate  310  of the module frame  300 . Preferably, the first partition wall member  510  has a shape corresponding to the flat plate, but may have a size corresponding to the upper portion of the battery cell stack  200 . 
     The second partition wall member  520  can be extended from the first partition wall member  510  to the lower portion  321  of the module frame  300 . Accordingly, a part of the plurality of battery cells  110  contained in the battery cell stack  200  may be spatially closed by the first partition wall member  510  and the second partition wall member  520 . 
     Further, the second partition wall member  520  may have a shape corresponding to the side portion  322  of the module frame  300 . Further, the second partition wall member  520  may have a shape corresponding to the battery cell  110  of the battery cell stack  200 . Preferably, the second partition wall member  520  has a shape corresponding to the flat plate, but may have a size corresponding to an upper surface or a lower surface of the battery cell  110 . 
     The partition wall portion  500  may include at least two second partition wall members  520 , and the second partition wall members  520  may be located separately from each other so as to have a predetermined interval in the stacking direction of the battery cell stack. As an example, the second partition wall members  520  may be located separately from each other so as to have equal intervals in the stacking direction of the battery cell stack. As an example, the second partition wall members  520  may be located symmetrically with reference to the center of the battery cell stack  200 . 
     As an example, the second partition wall members  520  are spaced apart in the stacking direction of the battery cell stack, but a region, where the battery cells  110  in the central region are located, may be located so that the second partition wall members  520  are spaced apart by a narrower interval than the battery cells  110  in the outer region. As the heat generated from the battery cell  110  is relatively less cooled in the battery cell  110  in the central region than in the battery cell  110  in the outer region, the probability of occurrence of a thermal event is high, so that the battery module  100  may more effectively control cell events. 
     In addition, the partition wall portion  500  may be configured such that at least one second partition wall member  520  is located between the outermost battery cell of the battery cell stack  200  and the module frame side portion  322 , or is located between the battery cells adjacent to each other among the plurality of battery cells  110 . 
     As an example, the partition wall portion  500  may be configured such that two second partition wall members  520  are respectively located between the outermost battery cells of the battery cell stack  200  and the module frame side  322 , and at least one second partition wall member  520  is located between the battery cells adjacent to each other among the plurality of battery cells. 
     As an example, the module frame  300  of the battery module  100  may include a U-shaped frame  320  that houses the battery cell stack  200  and has an opened upper portion, and an upper plate  310  that covers the battery cell stack  200  in the opened upper portion of the U-shaped frame. At this time, the first partition wall member  510  is located between the upper plate  310  and the battery cell stack  200 , two second partition wall members  520  are respectively located between the outermost battery cells of the battery cell stack  200  and the module frame side portion  322 , and at least one second partition wall member  520  may be located between the battery cells adjacent to each other among the plurality of battery cells  110 . 
     Thereby, the partition wall portion  500  can protect the outermost battery cells vulnerable to external impact in the battery cell stack  200 , and also can more effectively control cell events of the battery cell stack  200 . 
       FIG. 6  is a perspective view showing a state in which the components constituting the battery module of  FIG. 4  are combined.  FIG. 7  is a cross-sectional view showing a partial area of the cross-section taken along the cutting line B-B′ of  FIG. 6 . In particular,  FIG. 7  is an enlarged view showing a partial area of the battery cell stack  200  contained in a cross section taken along the cutting line B-B′ of  FIG. 6 . 
     Referring to  FIGS. 4, 5, and 7 , the battery module  100  according to an embodiment of the present disclosure includes a partition wall portion  500 , so that a plurality of battery cells  110  in the battery module  100  can be partitioned. As an example, the battery cell stack  200  may be partitioned into a first stack  111  and a second stack  113  by the partition wall portion  500 . At this time, the first stack  111  and the second stack  113  are electrically connected, but can be spatially separated. Preferably, the first stack  111  and the second stack  113  are spatially separated from each other, but each space can be closed. 
       FIG. 8  is a cross-sectional view showing the battery module of  FIG. 7  in which a cell event (CE) has occurred. Referring to  FIGS. 7 and 8 , when a cell event (CE) is occurred in the first stack  111 , the partition wall portion  500  may block the cell event (CE) from being diffused to the outside of the partition wall portion  500 . As an example, even if a cell event (CE) is occurred in the first stack  111 , the partition wall portion  500  may block the cell event (CE) from being diffused to the outside of the module frame  300  or the partition in which the second stack  113  is located. Thus, the partition wall portion  500  can have resistance to flames and venting gases generated in the cell event (CE), thereby preventing the cell event (CE) from being diffused to the outside. 
     Consequently, even if a cell event occurs in a specific battery cell  110 , it can prevent diffusion to other battery cells  110  and thus reduce the risk of occurrence of an additional cell event. Further, when a cell event occurs in a specific battery cell  110 , it is possible to induce the progression direction of the cell event only for the compartment in which the specific battery cell  110  is included, and thus prevent cell events from becoming severe. In addition, for the compartment including the specific battery cell  110  in which the cell event has occurred, the source in which the cell event has occurred can be quickly tracked and thus, product maintenance can be facilitated. 
     If necessary, the battery module  100  of the present disclosure may further include a thermally conductive resin layer (not shown) between the battery cell stack  200  and the partition wall portion  500  as a cooling means. Alternatively, a thermally conductive resin layer (not shown) may be further included between the partition wall portion  500  and the module frame  300 . Alternatively, a thermally conductive resin layer (not shown) may be further included between the battery cell stack  200  and the lower portion of the module frame  321 . Thereby, the battery module  100  of the present disclosure can prevent a cell event from occurring. 
     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 
       200 : battery cell stack 
       300 : module frame 
       500 : partition wall portion 
       600 : end plate