Abstract:
Disclosed herein is a battery cartridge having two or more unit cells mounted therein, wherein the battery cartridge includes a rotation part, which is formed at a cartridge case constructed generally with a plate-shaped structure, in the longitudinal direction of the battery cartridge and/or in the lateral direction of the battery cartridge, such that the battery cartridge can be folded by a predetermined angle in the longitudinal direction of the battery cartridge and/or in the lateral direction of the battery cartridge. The battery cartridge can be folded by a predetermined angle through the provision of the rotation part, and therefore, the battery cartridge is constructed in various structures as compared to the conventional rigid battery cartridge.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a foldable battery cartridge and a middle- or large-sized battery module including the same, and, more particularly, to a battery cartridge having two or more unit cells mounted therein, wherein the battery cartridge includes a rotation part, such as a hinge, which is formed at a cartridge case constructed generally with a plate-shaped structure, in the longitudinal direction of the battery cartridge and/or in the lateral direction of the battery cartridge, such that the battery cartridge can be folded by a predetermined angle in the longitudinal direction of the battery cartridge and/or in the lateral direction of the battery cartridge, and a middle- or large-sized battery module or battery pack including the same. 
     BACKGROUND OF THE INVENTION 
     In recent years, as concern about environmental pollution has increased, a secondary battery, which can be charged and discharged, has attracted considerable attention as a power source for vehicles in order to solve problems caused by existing gasoline and diesel vehicles using fossil fuel. As a result, electric vehicles (EV), which are operated only using a battery, and hybrid electric vehicles (HEV), which use jointly a battery and a conventional engine. Some of the electric vehicles and the hybrid electric vehicles have been commercially used. A nickel-metal hydride (Ni—MH) secondary battery has been mainly used as the power source for the electric vehicles (EV) and the hybrid electric vehicles (HEV). In recent years, however, the use of a lithium-ion secondary battery, which has high energy density and high discharge voltage, as the power source for the electric vehicles and the hybrid electric vehicles has been attempted. High output and large capacity are needed for such a secondary battery to be used as the power source for the electric vehicles (EV) and the hybrid electric vehicles (HEV). For this reason, a plurality of small-sized secondary batteries (unit cells) are connected in series with each other so as to construct a middle- or large-sized battery pack. 
     Plate-shaped cells, which can be stacked with high integration, are preferably used as the unit cells. The plate-shaped cells are mounted in additional battery cartridges, in order that low mechanical strength of the plate-shaped cells are compensated for, and the electrical connection and stacking of the plate-shaped cells are easily accomplished, whereby a middle- or large-sized battery module or battery pack is constructed. 
     The battery cartridges are formed in the shape of a hexahedron having a large width and length to thickness ratio (generally in the shape of a plate). The battery cartridges are constructed in a structure in which one or more unit cells are mounted in rigid cartridge cases. Consequently, the battery cartridges are successively stacked one on another, and are then electrically connected with each other, whereby a middle- or large-sized battery module or battery pack is manufactured. 
     The middle- or large-sized battery module or battery pack is widely used as a power source for large-sized devices, such as electric vehicles and hybrid electric vehicles. However, the inner spaces of the respective devices, in which the middle- or large-sized battery module or battery pack is mounted, are restricted. Also, as the devices have had various sizes and shapes, the devices may have a structure in which the battery module or the battery pack cannot be easily mounted in the inner spaces of the devices. 
     On the other hand, the change in shape of a conventional battery cartridge, which constitutes a middle- or large-sized battery module or battery pack, is not possible because of the rigid structure of the conventional battery cartridge. As a result, the conventional battery cartridge is not adaptable to the change in structure of the inner space of the corresponding device. Consequently, it is necessary to manufacture various battery modules or battery packs depending upon the structures of the inner spaces of the devices, and therefore, a large number of corrections, such as design change, are required during the manufacturing process, which is not preferable. 
     SUMMARY OF THE INVENTION 
     Therefore, the present invention has been made to solve the above-mentioned problems, and other technical problems that have yet to be resolved. 
     Specifically, it is an object of the present invention to provide a battery cartridge foldable such that a battery module or a battery pack including the battery cartridge can be manufactured in various structures. 
     It is another object of the present invention to provide a battery module or a battery pack, the shape of which can be changed by using the above-described battery cartridge. 
     In accordance with one aspect of the present invention, the above and other objects can be accomplished by the provision of a battery cartridge having two or more unit cells mounted therein, wherein the battery cartridge includes at least one rotation part, which is formed at a cartridge case constructed generally with a plate-shaped structure, in the longitudinal direction of the battery cartridge and/or in the lateral direction of the battery cartridge, such that the battery cartridge can be folded by a predetermined angle in the longitudinal direction of the battery cartridge and/or in the lateral direction of the battery cartridge. 
     Herein, the longitudinal direction of the battery cartridge means a direction in which connection terminals of the battery cartridge extend, and the lateral direction of the battery cartridge means a direction perpendicular to the direction in which the connection terminals of the battery cartridge extend. 
     Consequently, the battery cartridge according to the present invention can be folded by a predetermined angle due to the rotation part formed in the longitudinal direction and/or the lateral direction of the battery cartridge, and therefore, the battery cartridge according to the present invention can be constructed in various structures as compared to the conventional rigid battery cartridge. 
     In a preferred embodiment, one rotation part is formed in the longitudinal direction of the battery cartridge or in the lateral direction of the battery cartridge. According to circumstances, however, two or more rotation parts may be formed in the same direction of the battery cartridge. Furthermore, the rotation part may have various structures. For example, the rotation part may be constructed with a hinge structure or with a flexible bus bar structure. The rotation part includes a conductive region, which allows the electrical connection between the unit cells mounted in the battery cartridge. In the case that the rotation part is constructed with the hinge structure, the hinge rotation part itself is made of a conductive member or at least a portion of the hinge rotation part includes a conductive member. In the case that the rotation part is constructed with the flexible bus bar structure, on the other hand, the bus bar rotation part itself serves as an electrically connecting member. 
     The variable angle of the rotation part may be changed within ±180 degrees depending upon the structure of the rotation part. When the rotation part is varied by 180 degrees or by −180 degrees, the battery cartridge is fully folded, and therefore, the length of the folded battery cartridge is reduced to half of the length of the unfolded battery cartridge. 
     The cartridge case may comprise a variety of structures and materials. For example, the cartridge case may be constructed with an open-type frame structure or a close-type box structure, and the cartridge case may be made of a metal material or an insulating material, such as plastic resin. In the case that the cartridge case is made of the metal material, it is preferable that the cartridge case be constructed in a laminate structure in which the outer surface of the cartridge case is coated with an insulating material or an insulating layer is attached to the outer surface of the cartridge case. 
     The cartridge case is provided at the outer surface thereof with connection terminals, which are electrically connected to electrode terminals of the unit cells. 
     In a preferred embodiment, the cartridge case is further provided at the outer surface thereof with detection parts for detecting voltages and temperatures of the unit cells mounted in the cartridge case. The detection parts may be formed or may not be formed at the same side of the cartridge case. 
     One or more unit cells may be mounted in right-side and left-side members of the battery cartridge, which are divided from each other about the rotation part. The unit cells are not particularly restricted so long as the unit cells are formed in the shape of a plate. 
     Preferably, the electrode terminals of the unit cells are formed at the outsides of the battery cells such that the electrode terminals are opposite to each other or perpendicular to each other about the unit cells. Consequently, while the unit cells are mounted in the cartridge case, one electrode terminal (a cathode) of each of the unit cells is directly connected to the corresponding connection terminal of the battery cartridge, and the other electrode terminal (an anode) of each of the unit cells is directly connected to the rotation part. When two or more unit cells are mounted together in any one of the side members of the battery cartridge about the rotation part, the final electrode terminals are connected to the rotation part and the connection terminals of the battery cartridge, as described above, while the unit cells are connected in series or parallel with each other. 
     In a preferred embodiment, the rotation part is formed at the middle of the battery cartridge in the lateral direction of the cartridge case such that the battery cartridge can be folded in the longitudinal direction of the cartridge case, the unit cells, the electrode terminals of which are formed at the upper and lower ends of the battery cells while the electrode terminals of the unit cells are opposite to each other, are mounted in the battery cartridge such that one electrode terminal of each of the unit cells is directly connected to the rotation part, and the other electrode terminal of each of the unit cells is directly connected to the corresponding connection terminal of the battery cartridge, and the connection terminals of the battery cartridge are formed at the upper and lower ends of the cartridge case, which are opposite to the rotation part. 
     However, the above-described structure is only an illustrative example, and therefore, it is possible to provide other various structures. 
     In accordance with another aspect of the present invention, there is provided a middle- or large-sized battery module including two or more battery cartridges having the above-described structure. 
     The battery cartridges can be folded by the corresponding rotation parts, and therefore, the battery module may have various structures. For example, the battery module may be constructed: (1) in a structure in which the two or more battery cartridges are successively stacked one on another while the respective two or more battery cartridges are unfolded; (2) in a structure in which the two or more battery cartridges are successively stacked one on another after the respective two or more battery cartridges are folded by 180 degrees; (3) in a structure in which the two or more battery cartridges are connected with each other in the side directions of the two or more battery cartridges while the two or more battery cartridges are folded and/or unfolded; or (4) in a structure in which the two or more battery cartridges are stacked one on another or connected with each other in the side directions of the two or more battery cartridges while some of the two or more battery cartridges are folded and the other of the two or more battery cartridges are unfolded. 
     The battery module according to the present invention may be changed in shape in response to the restricted inner space of a device, in which the battery modules are mounted, and may be then mounted in the restricted inner space of a device, because of the foldability of the battery cartridges, which constitute the battery module. For example, in the case that the inner space of the device is narrow and long, but is not straight, some of the battery cartridges are folded by a predetermined angle, and are then connected with each other in the side directions of the battery cartridges, whereby the battery module is constructed. In the case that the inner space of the device has a small sectional area and a large length, on the other hand, the battery cartridges are fully folded as in the above-described structure (2), such that the sectional area of the battery cartridges is reduced, and are then stacked one on another in the longitudinal direction of the battery module, whereby the battery module is constructed. 
     The above-mentioned variability is one of the striking characteristics of the battery module according to the present invention. 
     Herein, the “battery pack” means a complete structure in which electrically connecting units and an operation control unit are mounted in the battery module. Also, the “battery pack” means a middle- or large-sized battery system comprising a plurality of battery modules. Consequently, the battery module and the battery pack are not interpreted to have different meanings. 
     Preferably, the battery module or the battery pack according to the present invention is used as a power source for electric vehicles (EV), hybrid electric vehicles (HEV), electric motorcycles, and electric bicycles. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a typical view illustrating a battery cartridge according to a preferred embodiment of the present invention; 
         FIG. 2  is a typical view illustrating the fully folded state of the battery cartridge shown in  FIG. 1 ; 
         FIG. 3  is a typical view illustrating a battery module according to a preferred embodiment of the present invention, which is constructed using a plurality of battery cartridges, one of which is shown in  FIG. 1 ; and 
         FIG. 4  is a typical view illustrating a battery module according to another preferred embodiment of the present invention, which is constructed using a plurality of battery cartridges, one of which is shown in  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Now, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted, however, that the scope of the present invention is not limited by the illustrated embodiments. 
       FIG. 1  is a typical view illustrating a battery cartridge according to a preferred embodiment of the present invention. 
     Referring to  FIG. 1 , the battery cartridge  100  comprises two plate-shaped members  110  and  120 , which are connected with each other such that the plate-shaped members  110  and  120  can be hingedly rotated by a hinge rotation part  200 . In the respective plate-shaped members  110  and  120  are mounted unit cells  310  and  320 , respectively. For convenience of description, the plate-shaped members  110  and  120  are shown in a seal-type structure. 
     From the upper ends of the plate-shaped members  110  and  120  protrude connection terminals  111  and  121 , respectively. The connection terminals  111  and  121  are connected to electrode terminals (not shown) of the unit cells  310  and  320  mounted in the plate-shaped members  110  and  120 , respectively. 
     For example, a cathode terminal of the unit cell  310  mounted in the first plate-shaped member  110  is connected to the connection terminal  111 , and an anode terminal of the unit cell  310  mounted in the first plate-shaped member  110  is connected to a conductive member of the hinge rotation part  200 . Similarly, an anode terminal of the unit cell  320  mounted in the second plate-shaped member  120  is connected to the connection terminal  121 , and a cathode terminal of the unit cell  320  mounted in the second plate-shaped member  120  is connected to the conductive member of the hinge rotation part  200 . In the above-described structure, the unit cells  310  and  320  are connected in series with each other. For easy electrical connection, the electrode terminals of the unit cells  310  and  320  protrude from the upper and lower ends of the battery cells while the electrode terminals of the unit cells  310  and  320  are opposite to each other. Also, in the case that two or more unit cells are mounted in each of the plate-shaped members  110  and  120 , the final electrode terminals are connected to the connection terminals and the conductive member of the hinge rotation part  200  while the unit cells are electrically connected with each other. 
     At the upper ends of the plate-shaped members  110  and  120  are formed detection parts  112  and  122  for detecting voltages and temperatures of the corresponding unit cells. The detection parts  112  and  122  may be located at the side parts of the plate-shaped members  110  and  120  such that the positional overlapping between the detection parts  112  and  122  and the connection terminals  111  and  121  is prevented. 
     The upper and lower ends  113 ,  114 ,  123 , and  124  of the inside surfaces of the plate-shaped members  110  and  120  protrude from the plate-shaped members  110  and  120 , respectively. Consequently, when the battery cartridge  100  is fully folded as shown in  FIG. 2 , the middle parts of the inside surfaces of the plate-shaped members  110  and  120  are spaced apart from each other. Similarly, the upper and lower ends  115 ,  116 ,  125 , and  126  of the outside surfaces of the plate-shaped members  110  and  120  protrude from the plate-shaped members  110  and  120 , respectively. Consequently, when the plate-shaped members  110  and  120  are stacked on other plate-shaped members as shown in  FIG. 3  or  4 , the middle parts of the outside surfaces of the plate-shaped members  110  and  120  are spaced apart from the middle parts of the inside surfaces of the other plate-shaped members or from the middle parts of the outside surfaces of the other plate-shaped members. The above-mentioned “inside surface” and the above-mentioned “outside surface” mean the inner surface and the outer surface of the battery cartridge  110  when the battery cartridge  110  is folded as shown in  FIG. 2 . 
     Gaps  130  and  132 , which are defined between the middle parts of the inside surfaces of the plate-shaped members  110  and  120  of the fully folded battery cartridge  100  and between the middle parts of the outside surfaces of the plate-shaped members  110  and  120  and the middle parts of the corresponding inside surfaces of the neighboring plate-shaped members or the corresponding outside surfaces of the neighboring plate-shaped members, are used as channels for refrigerant, such as air, by which heat generated from the unit cells during the charge and discharge of the unit cells is effectively removed. 
     Referring back to  FIG. 1 , the lower end  117  of the first plate-shaped member  110 , which constitutes the hinge rotation part  200 , is constructed in a protrusion structure, and the lower end  127  of the second plate-shaped member  120 , which corresponds to the lower end  117  of the first plate-shaped member  110 , is constructed in a depression structure. Consequently, when battery cartridges are stacked one on another while the respective battery cartridges are fully folded as shown in  FIG. 4 , the adjacent battery cartridges are not prevented from being stacked one on another. 
     The hinge rotation part  200  itself or a connection shaft  210  of the hinge rotation part  200  is made of a conductive member, and the hinge rotation part  200  or the connection shaft  210  of the hinge rotation part  200  are connected to the electrode terminals of the unit cells mounted in the respective plate-shaped members  110  and  120 , whereby the electrical connection between the first plate-shaped member  110  and the second plate-shaped member  120  is accomplished. 
     Due to the hinge rotation part  200 , the first plate-shaped member  110  and the second plate-shaped member  120  can be rotated by a predetermined angle with respect to each other. 
       FIG. 2  is a typical view illustrating the fully folded state of the battery cartridge shown in  FIG. 1 . 
     Referring to  FIG. 2 , the first plate-shaped member  110  and the second plate-shaped member  120  are brought into contact with each other, whereby the length of the folded battery cartridge  100  is reduced to half of the length of the unfolded battery cartridge  100 . However, it is also possible that the first plate-shaped member  110  and the second plate-shaped member  120  are rotated by different angles with respect to each other. 
     When the battery cartridge is folded, the connection terminals  111  and  121  and the detection parts  112  and  122  are not located on the same axis. The electrical connection between the connection terminals  111  and  121  and the connection between the detection parts  112  and  122  are easily accomplished through the above-mentioned structure. 
     As previously described, the gap  130  is defined between the middle parts of the inside surfaces of the plate-shaped members  110  and  120  when the battery cartridge  100  is fully folded, and the heat dissipation from the unit cells mounted in the battery cartridge  100  is effectively accomplished due to the gap  130 . 
       FIG. 3  is a typical view illustrating a battery module according to a preferred embodiment of the present invention, which is constructed using a plurality of battery cartridges, one of which is shown in  FIG. 1 . 
     Referring to  FIG. 3 , the battery module  300  is constructed in a structure in which a plurality of battery cartridges  101 ,  102 ,  103 , and  104  are successively stacked one on another while the respective battery cartridges  101 ,  102 ,  103 , and  104  are fully unfolded as shown in  FIG. 1 . This structure of the battery module  300  is substantially identical to the structure of a module constructed by stacking conventional rigid plate-shaped battery cartridges. 
     As previously described, the gaps  132  are defined between the middle parts of the inner surfaces of the stacked battery cartridges  101 ,  102 ,  103 , and  104  and the middle parts of the corresponding outer surfaces of the adjacent battery cartridges, whereby the heat dissipation from the unit cells mounted in the battery cartridges  101 ,  102 ,  103 , and  104  is effectively accomplished due to the gap  132 . 
       FIG. 4  is a typical view illustrating a battery module according to another preferred embodiment of the present invention, which is constructed using a plurality of battery cartridges, one of which is shown in  FIG. 1 . 
     Referring to  FIG. 4 , the battery module  400  is constructed in a structure in which a plurality of battery cartridges  101 ,  102 ,  103 , and  104  are successively stacked one on another while the respective battery cartridges  101 ,  102 ,  103 , and  104  are fully folded as shown in  FIG. 2 . The battery module  400  of  FIG. 4  has a width less than that of the battery module  300  of  FIG. 3  but a height greater than that of the battery module  300  of  FIG. 3 . 
     As previously described, the gaps  132  are defined between the middle parts of the outer surfaces of the stacked battery cartridges  101 ,  102 ,  103 , and  104  and the middle parts of the corresponding outer surfaces of the adjacent battery cartridges, whereby the heat dissipation from the unit cells mounted in the battery cartridges  101 ,  102 ,  103 , and  104  is effectively accomplished due to the gap  132 . 
     The battery modules  300  and  400  of  FIGS. 3 and 4  represent the typical construction of the module using the battery cartridge  100  of  FIG. 1 , although the battery module may be constructed in various manners. 
     INDUSTRIAL APPLICABILITY 
     As apparent from the above description, the battery cartridge includes the rotation part, by which the battery cartridge can be folded by a predetermined angle, and therefore, the battery cartridge is constructed in various structures as compared to the conventional rigid battery cartridge. Also, the battery module including the above-mentioned battery cartridge can be actively constructed such that the shape of the battery module can be changed depending upon the inner space of a device in which the battery module is mounted. Consequently, it is not necessary to manufacture additional battery cartridges or additional battery modules depending upon the shape of the inner space of the device, and therefore, costs caused due to the design change of the battery cartridge or the battery module are considerably reduced. 
     Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.