Patent Publication Number: US-2015064544-A1

Title: Battery module

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     Korean Patent Application No. 10-2013-0101587, filed on Aug. 27, 2013, in the Korean Intellectual Property Office, and entitled: “Battery Module,” is incorporated by reference herein in its entirety. 
     BACKGROUND 
     1. Field 
     Embodiments relate to a battery module. 
     2. Description of the Related Art 
     A high-power battery module using a non-aqueous electrolyte with high energy density has been considered. The high-power battery module may be configured as a large-capacity battery module manufactured by connecting a plurality of battery cells in series so as to be used in driving motors of devices requiring high power, e.g., electric vehicles or the like. Further, a battery pack can be configured by electrically connecting such a plurality of battery modules to one another. 
     SUMMARY 
     Embodiments are directed to a battery module. 
     The embodiments may be realized by providing a battery module including a plurality of battery cells aligned in one direction; and a bus-bar electrically connecting between a first terminal of one battery cell of the plurality of battery cells and a second terminal of another battery cell of the plurality of battery cells, wherein the bus-bar includes a bus-bar body, and bending portions, the bending portions extending from ends of the bus-bar body. 
     The bus-bar body may have a plate shape. 
     The bending portions may each have a semicircular shape in cross-section or a semi-elliptical shape in cross-section. 
     The bending portions may each have a roughly “V” shape in cross-section. 
     The bending portions, each having the roughly “V” shape in cross-section, may each include a first slope portion extending downwardly from one end of the bus-bar body, and a second slope portion extending upwardly from the first slope portion. 
     The second slope portion may be surface-adhered closely to the first or second terminal by folding the bending portion in a direction of the first or second terminal. 
     The bending portion may further include a cut-away groove between the first and second slope portions. 
     The bending portions, each having the roughly “V” shape in cross-section, may each include a first slop portion extending from an end of the bus-bar body and being inclined with respect to the bus-bar body, and a second slope portion extending from an end of the first slope portion and inclined with respect to the first slope portion. 
     The end of the first slope portion from which the second slope portion extends may be opposite to another end of the first slope portion that is adjacent to the bus-bar body. 
     The second slope portion may extend in parallel with and may be coupled with the first terminal of the one battery cell or the second terminal of the other battery cell. 
     The bending portions may each have a semicircular shape in cross-section, and a radius of the bending portion may be greater than a vertical distance between an end of the bus-bar and one surface of a terminal that has a higher height among the first and second terminals. 
     The vertical distance may be determined using at least one of a length from a point at which the bending portion is contacted with one surface of the terminal with the high height, a distance between points at which the bending portions are respectively contacted with one surface of the first and second terminals, a height difference between the first and second terminals, an angle at which the bus-bar is inclined by the height difference, and a thickness of the bus-bar. 
     The bending portion may be welded to a top surface of the first terminal or the second terminal. 
     The bending portion may be welded to the top surface of the first terminal or the second terminal by laser welding or ultrasonic welding. 
     A top surface of the first terminal may be on a different plane relative to a top surface of the second terminal. 
     The bus-bar may be formed of gold, silver, copper, nickel, aluminum, a copper alloy, or an aluminum alloy. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Features will be apparent to those of skill in the art by describing in detail exemplary embodiments with reference to the attached drawings in which: 
         FIG. 1  illustrates a perspective view of a battery module according to an embodiment. 
         FIG. 2  illustrates an exploded perspective view of the battery module shown in  FIG. 1 . 
         FIG. 3  illustrates a sectional view showing a state in which a bus-bar is fastened to a terminal portion when a height difference exists between two battery cells. 
         FIG. 4  illustrates a perspective view of a bus-bar of  FIG. 2 . 
         FIG. 5  illustrates a sectional view of the bus-bar of  FIG. 2 . 
         FIG. 6  illustrates a sectional view showing a state in which the bus-bar of  FIG. 2  is fastened to a terminal portion. 
         FIG. 7  illustrates a sectional view of a bus-bar of a battery module according to an embodiment. 
         FIG. 8  illustrates a perspective view of the bus-bar of  FIG. 7 . 
         FIGS. 9A and 9B  illustrate sectional views showing a state in which a bus-bar of a battery module is fastened to a terminal portion. 
         FIG. 10  illustrates a perspective view of a bus-bar of a battery module according to still another embodiment. 
         FIGS. 11A and 11B  illustrate sectional views of different states of the bus-bar shown in  FIG. 10 . 
     
    
    
     DETAILED DESCRIPTION 
     Example embodiments will now be described more fully hereinafter with reference to the accompanying drawings; however, they may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey exemplary implementations to those skilled in the art. 
     In the drawing figures, the dimensions of layers and regions may be exaggerated for clarity of illustration. Like reference numerals refer to like elements throughout. 
     It will be understood that when an element is referred to as being “between” two elements, it can be the only element between the two elements, or one or more intervening elements may also be present. In addition, when an element is referred to as being “on” another element, it can be directly on the other element or be indirectly on the other element with one or more intervening elements interposed therebetween. Also, when an element is referred to as being “connected to” another element, it can be directly connected to the other element or be indirectly connected to the other element with one or more intervening elements interposed therebetween. 
       FIG. 1  illustrates a perspective view of a battery module  100  according to an embodiment.  FIG. 2  illustrates an exploded perspective view of the battery module  100  shown in  FIG. 1 . Hereinafter, the battery module  100  according to this embodiment will be described with reference to  FIGS. 1 and 2 . 
     As shown in  FIGS. 1 and 2 , the battery module  100  according to an embodiment may include a plurality of battery cells  110  aligned in one direction, a bus-bar  120  electrically connecting between terminal portions  111  of different (e.g., adjacent) battery cells  110 , and a cover member  150  that covers top surfaces  118  of the battery cells  110  (each battery cell  110  having the terminal portion  111 ). 
     The battery cell  110  may be a member that generates energy. The plurality of battery cells  110  may be aligned in one direction. 
     Each battery cell  110  may include a battery case (of which one surface or side is opened), and an electrode assembly and an electrolyte (which are accommodated in the battery case). The electrode assembly and the electrolyte may generate energy through an electrochemical reaction therebetween. The battery case may be hermetically sealed at a top surface  118  of the battery cell  110  including, e.g., a cap assembly. The terminal portion  111  may protrude from the top surface  118  of the battery cell  110 . In an implementation, the terminal portion  111  may include a first terminal (positive or negative electrode terminal)  112  and a second terminal (negative or positive electrode terminal)  113 , which have different polarities from each other. A vent  114  (acting as a passage through which gas generated in the battery cell  110  is exhausted to the outside of the battery cell  110 ) may be further formed in the top surface  118  of the battery cell  110  as a safety device of the battery cell  110 . 
     The battery module  100  may further include a fixing portion  115  to align the battery cells  110  in the one direction. In an implementation, the fixing portion  115  may include a pair of end plates  116  (disposed at outsides of the battery cells  110 ), and a connecting plate  117  (connecting between the end plates  116 ). The plurality of battery cells  110  may be aligned between the pair of end plates  116 . In an implementation, the battery cells  110  may be aligned in parallel so that wide front surfaces of the battery cells  110  are opposite to or face each other. The fixing portion  115  may stably fix the battery cells  110 . The fixing portion  115  may be variously modified and embodied. 
     For example, the shape of a housing (entirely accommodating the battery cells  110 ) may also be included in the fixing portion  115 . The connection structure of the battery cells  110  and the number of the battery cells  110  may be variously modified according to the design of the battery module  100 . In an implementation, and as illustrated in  FIGS. 1 and 2 , adjacent battery cells  110  may contact each other. In an implementation, the adjacent battery cells  110  may be positioned to be spaced apart from each other, or a spacer may be provided in a space between the adjacent battery cells  110 . 
     The cover member  150  may cover the top surface  118  of the battery cell  110 , e.g., a surface of the battery cell  110  from which the terminal portion  111  protrudes. Accordingly, it is possible to help prevent the terminal portion  111  or the bus-bar  120  from being short-circuited with an external conductor. 
     The bus-bar  120  may be a member that allows the terminal portions  111  of different battery cells  110  to be electrically connected to each other. 
     In an implementation, the bus-bar  120 , as shown in  FIG. 2 , may allow two battery cells  110  to be connected in series to each other by electrically connecting the first terminal  112  of any one battery cell  110  to the second terminal  113  of another battery cell  110  (e.g., adjacent to the one battery cell  110 ). In an implementation, the bus-bar  120  may connect two battery cells  110  in parallel to each other by electrically connecting the second terminal  113  of any one battery cell  110  to the second terminal  113  of another battery cell  110  adjacent to the one battery cell  110 . In an implementation, the bus-bar  120  may be formed of, e.g., an electrically conductive metal such as gold, silver, copper, nickel, aluminum, a copper alloy, or an aluminum alloy, so as to electrically connect between the terminal portions  111 . The bus-bar  120  may be bonded to the terminal portions  111  through welding, e.g., the bus-bar  120  may be welded to the terminal portions  111 . In an implementation, the welding between the bus-bar  120  and the terminal portion  111  may include, e.g., laser welding or ultrasonic welding. 
     In order to weld the terminal portion  111  and the bus-bar  120 , precise and/or close adhesion between the terminal portion  111  and the bus-bar  120  may be desirable. 
       FIG. 3  illustrates a sectional view showing a state in which a bus-bar is fastened to the terminal portion  111  when a height difference exists between two battery cells  110 . 
     If a height difference exists between two battery cells  110 , e.g., as shown in  FIG. 3 , the first and second terminals  112  and  113  (e.g., top surfaces of the first and second terminals  112  and  113 ) may form or may be on different planes. Therefore, a bus-bar  320  may not be surface-adhered closely to the second terminal  113  in area A, and one end of the bus-bar  320  may come off Accordingly, the battery cells  110  may be precisely manufactured so that there exists no height difference between two battery cells  110 , or the bus-bar  320  may be manufactured using a flexible material (in addition to copper). However, ensuring that there is not a height difference between the two battery cells  110  or that the bus-bar  320  is manufactured using a flexible conductive material may cause an increase in cost and complexity in manufacturing and assembling processes of the battery module  100 . In addition, it may be difficult to ensure the quality of the battery module  100 . 
     According to an embodiment, bending portions  132  may be bent at ends, e.g., both ends, of the bus-bar  120 , so that it is possible to compensate for a height difference between the two battery cells  110 . 
       FIG. 4  illustrates a perspective view of the bus-bar of  FIG. 2 .  FIG. 5  illustrates a sectional view of the bus-bar of  FIG. 2 .  FIG. 6  illustrates a sectional view showing a state in which the bus-bar of  FIG. 2  is fastened to the terminal portion. Hereinafter, the bus-bar  120  according to this embodiment will be described in detail with reference to  FIGS. 4 to 6 . 
     The bus-bar  120  may include a bus-bar body  131  and bending portions  132 . 
     The bus-bar body  131  may have a plate shape. The bending portions  132  may be respectively bent at ends, e.g., both ends, of the bus-bar body  131 . Each bending portion  132  may have a roughly “U” shaped cross-section, e.g., may have semicircular shaped cross-section or a semi-elliptical shaped cross-section. 
     The bending portions  132  may contact top surfaces of the first and second terminals  112  and  113 . Thus, even if a height difference exists between two adjacent battery cells  110 , the bus-bar  120  may be stably and closely adhered to the terminal portion  111 , due to the bent shape of the bending portion  132 . 
     For example, the first and second terminals  112  and  113  may be stably electrically connected by the bus-bar  120 . The top surfaces of the first and second terminals  112  and  113  may be bonded to one of the bending portions  132  through welding, e.g., the top surfaces of the first and second terminals  112  and  113  may be welded to the one bending portion  132 . The welding may include, e.g., laser welding or ultrasonic welding. 
     In an implementation, a radius of the bending portion  132  may be greater than a vertical distance K between an end of the bus-bar  120  and one surface of a terminal (e.g., the one terminal that has a higher height among the first and second terminals  112  and  113 ). 
     For example, the vertical distance K may be derived from the following Equation 1. 
         K =tan θD l   +T /2
 
       θ=tan −1  ( d/D   ω )   Equation 1
 
     Here, D l , denotes a length from a point at which the bending portion contacts one surface , e.g., the top surface, of the terminal having the higher height (among the first and second terminals  112  and  113 ). D ω  denotes a distance between the points at which the bending portions  132  contact surfaces of the first and second terminals  112  and  113 . d denotes a height difference between the first and second terminals  112  and  113 . θ denotes an angle at which the bus-bar  120  is inclined by the height difference. T denotes a thickness of the bus-bar  120 . 
       FIG. 7  illustrates a sectional view of a bus-bar of a battery module according to an embodiment.  FIG. 8  illustrates a perspective view of the bus-bar of  FIG. 7 .  FIGS. 9A and 9B  illustrate sectional views showing a state in which the bus-bar of  FIG. 7  is fastened to or coupled with a terminal portion. Hereinafter, the bus-bar according to the present embodiment will be described with reference to  FIGS. 7 to 9B . Here, components identical or corresponding to those of the aforementioned embodiment are designated by like reference numerals, and repeated detailed descriptions may be omitted to avoid redundancy. 
     As shown in  FIGS. 7 and 8 , the bus-bar  720  may include a bus-bar body  731  and bending portions  732 . 
     The bus-bar body  731  may have a plate shape. The bending portions  732  may be bent at ends, e.g., both ends, of the bus-bar body  731 . In an implementation, the bending portion  732  may have a roughly “V” shaped cross-section. 
     The bending portion  732  may include a first slope portion  732   a  extending from an end of the bus-bar body  731  and inclined at an angle with respect to the bus-bar body  731 . For example, the first slope portion  732   a  may extend downwardly from the end of the bus-bar body  731 . The bending portion  732  may include a second slope portion  732   b  extending from the first slope portion  732   a  and inclined at an angle with respect to the first slope portion  732   a.  For example, the second slope portion  732   b  may extend upwardly from the first slope portion  732   a.  For example, the second slope portion  732   b  may extend from an end of the first slope portion  732   a  that is opposite to another end of the first slope portion  732   a  that is adjacent to the bus-bar body  731 . 
     In an implementation, the second slope portion  732   b  of the bending portion  732  may be foldable. 
       FIG. 9A  illustrates a sectional view showing a state in which the bus-bar is fastened to or coupled with the terminal portion before the second slope portion is folded.  FIG. 9B  illustrates a sectional view showing a state in which the bus-bar is fastened to or coupled with the terminal portion after the second slope portion is folded. 
     For example, as shown in  FIG. 9B , the second slope portion  732   b  may be surface adhered closely to the first or second terminal  112  or  113  by folding the bending portion  732  in a direction of or parallel with the first or second terminal  112  or  113 . Thus, the bus-bar  720  may be stably and closely adhered to or coupled with the terminal portion  111 , even when a height difference exists between two battery cells  110 . For example, the bending portions  732  may head have the roughly “V” shape, but may have internal angles of the roughly “V” shape that are different from one another, when the bending portions  732  are coupled with the terminal portions  111 . For example, each second slope portion  732   b  may be parallel with top surfaces of the terminal portions  111  when the second slope portions  732   b  are closely coupled thereto. 
     In this case, the top surfaces of the first and second terminals  112  and  113  may be bonded to the second slope portions  732   b  through welding. The welding may include, e.g., laser welding or ultrasonic welding. 
       FIG. 10  illustrates a perspective view of a bus-bar of a battery module according to still another embodiment.  FIGS. 11A and 11B  illustrate sectional views of states of the bus-bar of  FIG. 10 . Hereinafter, the bus-bar according to the present embodiment will be described with reference to  FIGS. 10 ,  11 A, and  11 B. Here, components identical or corresponding to those of the aforementioned embodiment are designated by like reference numerals, and repeated detailed descriptions may be omitted to avoid redundancy. 
     As shown in  FIGS. 10 ,  11 A, and  11 B, the bus-bar  1120  may include a bus-bar body  1031  and bending portions  1032 . 
     The bus-bar body  1031  may have a plate shape. The bending portions  1032  may have a roughly “V”-shaped cross-section. The bending portions  1032  may be bent at ends, e.g., both ends, of the bus-bar body  1031 . 
     The bending portion  1032  may include a first slope portion  1032   a  extending from an end of the bus-bar body  1031  and inclined at an angle with respect to the bus-bar body  1031 . For example, the first slope portion  1032   a  may extend downwardly from the end of the bus-bar body  1031 . The bending portion  1032  may include a second slope portion  1032   b  extending from the first slope portion  1032   a  and inclined at an angle with respect to the first slope portion  1032   a.  For example, the second slope portion  1032   b  may extend upwardly from the first slope portion  1032   a.  For example, the second slope portion  1032   b  may extend from an end of the first slope portion  1032   a  that is opposite to another end of the first slope portion  1032   a  that is adjacent to the bus-bar body  1031 . The bending portion  1032  may include a cut-away groove  1032   c  between the first and second slope portions  1032   a  and  1032   b.    
     In an implementation, the second slope portion  1032   b  of the bending portion  1032  may be foldable. 
       FIG. 11  A illustrates a sectional view of the bus-bar before the second slope portion is folded.  FIG. 11B  illustrates a sectional view of the bus-bar after the second slope portion is folded. 
     As shown in  FIG. 11B , the second slope portion  1032   b  may be surface-adhered closely to the first or second terminal  112  or  113  by folding the bending portion  1032  in the direction of or parallel with the first or second terminal  112  or  113 . For example, the cut-away groove  1032   c  may facilitate the folding of the second slope portion  1032   b . For example, the second slope portion  1032   b  may be folded outwardly to be parallel with the top surface of an underlying first or second terminal  112  or  113 . 
     By way of summation and review, as the number of devices employing the battery module increases, improving the productivity of the battery module has been considered. As the external appearance of the devices is diversified, a shape of the battery module may be varied. However, the safety of the battery module may be basically secured. Therefore, a structure of a battery module that is capable of satisfying all the requirements have been considered. 
     A bus-bar may be used as a member that connects a plurality of battery cells. If a height difference exists between battery cells, the bus-bar may not be precisely adhered closely to electrode terminals of the battery cells. 
     As described above, the bending portions  132 ,  732 , or  1032  may be at ends, e.g., at both ends, of the bus-bar  120 ,  720 , or  1120 , so that the bus-bar  120 ,  720 , or  1120  may be stably and closely adhered to or coupled with the terminal portion  111 , even if a height difference exists between two battery cells  110 . 
     The embodiments may provide a bus-bar that may be precisely adhered closely to electrode terminals of adjacent battery cells, even when a height difference exists between the adjacent battery cells. 
     According to an embodiment, the bending portions may be at ends of the bus-bar, so that the bus-bar may be stably adhered closely to the electrode terminals of adjacent battery cells, even when a height difference exists between the adjacent battery cells. 
     Example embodiments have been disclosed herein, and although specific terms are employed, they are used and are to be interpreted in a generic and descriptive sense only and not for purpose of limitation. In some instances, as would be apparent to one of ordinary skill in the art as of the filing of the present application, features, characteristics, and/or elements described in connection with a particular embodiment may be used singly or in combination with features, characteristics, and/or elements described in connection with other embodiments unless otherwise specifically indicated. Accordingly, it will be understood by those of skill in the art that various changes in form and details may be made without departing from the spirit and scope of the present invention as set forth in the following claims.