Solar cell module
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a solar cell module and more particularly to a solar cell module having an improved construction of plural solar cell modules to be connected securely and easily. 
     2. Prior Art 
     A solar cell module case including plural solar cell devices and having a concave section on its side wall and a convex section on its opposite side wall has been proposed, wherein the concave and convex sections have terminals for the solar cell devices, whereby the convex section of a module case is inserted into the concave section of another module cases so that both solar cell modules can be connected to each other electrically and mechanically. 
     However, the connection made by inserting the convex section of a module case into the concave section of another module case is susceptible to the force applied in the direction opposite to or perpendicular to the insertion direction. The connection is also susceptible to the force exerted to twist the module cases. If the module cases are connected one after another on a plane, the connection may be disconnected at some connection points. Even when the connection is not disconnected, the output of the solar cells cannot be obtained if the connection is improper. Thus the connected solar modules cannot function as solar cells. 
     Since solar cells are generally used outdoors, the electrical and mechanical connection of the solar cell modules must be done securely and firmly. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to eliminate the above-mentioned defects and to provide a solar cell module construction which allows electrical and mechanical connection of a plurality of solar cell modules to be done securely and easily. Other objects and advantages of the present invention will become more apparent in the following description when considered in connection with the accompanying drawings. 
    
    
     BRIEF EXPLANATION OF THE DRAWINGS 
     FIG. 1 (A) is a perspective view illustrating an embodiment of a solar cell module of the present invention; 
     FIG. 1(B) is a perspective view of the solar cell module 1 of FIG. 1 (A) taken in the X direction of FIG. 1 (A); and 
     FIG. 2 and FIG. 3 are top views of the solar cell modules of the present invention to help explain the connection of the modules. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now in detail to the drawings, a solar cell module 1 includes a module case 2 made of transparent glass or resin on its upper surface and plural solar cell devices which are accommodated in the module case 2 and connected electrically. The module case 2 is formed in a rectangular shape so that the module cases can be connected one after another in series, parallel or matrix. Projected sections 4 and 6 are formed on side walls 3a and 3b of the module case 2. 
     Recessed groove sections 5 and 7 are correspondingly formed on side walls 3c and 3d which are located on the opposite sides of the side walls 3a and 3b respectively. 
     Since the projected sections 4 and 6 are substantially identical to each other, and the groove sections 5 and 7 are also substantially identical to each other, only the projected section 4 and the groove section 5 are explained in detail to prevent repetition. 
     The projected section 4 is shown as a rail-shaped section 10 running nearly all along the center line of the side wall 3a of the module case 2. The rail-shaped section 10 is equipped with two engagement sections 11 which will be described later as the first-engagement sections. The thickness of the rail-shaped section 10 is determined so that it is able to be slid and inserted into the groove section 5 as described later. An L-shaped jutted section L and a groove space S enclosed by the L-shaped jutted section L are provided on the top and bottom surfaces of the rail-shaped section 10 to form each engagement section 11. 
     On the other hand, the groove section 5 is a straight channel formed along the entire length of the side wall 3c which is located on the opposite side of the side wall 3a of the module case 2. The second-engagement sections 12 are provided at two positions on the groove section 5, each of which is composed of a pair of projected walls 120 on the upper and lower surfaces of the groove section 5. 
     The second-engagement section 12 has configurations and dimensions so that it can be inserted or pressure-fit into the groove space S of the projected section 4. The space between a pair of the projected walls 120 is determined so that it can accommodate the rail section 10 of the projected section 4. The width of the groove section 5 where the second-engagement sections 12 are not provided is determined so that the space made by the groove section 5 can accommodate the L-shaped jutted section L. The depth of the groove section 5 is determined so that the projected section 4 can be fully inserted into the groove section 5 and so that the side wall 3a of a module case can contact the side wall 3c of another module. 
     When the projected section 4 of the module case is inserted into the groove section 5 of another module case to connect these two module cases, both cases are aligned in the longitudinal direction and the first-engagement section 11 of the projected section 4 abuts the second-engagement section 12 of the groove section 5 at the regular connection position where the terminals (described later) of the modules are connected to each other so that the projected section 4 cannot be directly inserted into the groove section 5. This connection method is described later. 
     Terminals 8a, 8b, 9a, and 9b of the solar cell devices are provided on the outer surfaces of the rail-shaped sections 10 of the projected sections 4 and 6 of the module case 2. Terminals 8c, 8d, 9c, and 9d are also provided on the inner surfaces of the groove sections 5 and 7. The terminals 8a-8d are connected to the solar cell devices in parallel, and the terminals 9a-9d are connected to the solar cell devices in series. 
     Accordingly, two modules can be connected in parallel by electrically connecting the terminals 8a and 8b provided on the projected section 4 of a module case to the terminals 8c and 8d (the distance between the terminals 8c and 8d is identical to that between the terminals 8a and 8b) provided on the groove section 5 of another module case. Furthermore, two modules can be connected in series by electrically connecting the terminals 9a and 9b on the projected section 6 of a module to the terminals 9c and 9d (the distance between the terminals 9c and 9d is identical to that between the terminals 9a and 9b) provided on the groove section 7 of another module case. 
     In addition, the preferred embodiment of the solar cell module of the present invention is provided with marks which indicate the specified insertion reference positions when the module cases are connected to each other. The embodiment is also provided with marks which indicate the positions where the module cases are properly connected. 
     For example, triangular marks 20, 21, 22, and 23 are respectively provided close to the side walls 3a, 3b, 3c, and 3d of the module case 2. 
     V-shaped marks 24 and 25 are respectively provided close to the side walls 3a and 3b. 
     When two module cases are connected to each other, the triangular marks 20, 21, 22, and 23 indicate whether the connection is done properly or not by judging whether the triangular marks are aligned with those on another module case or not. 
     The V-shaped marks 24 and 25 indicate the insertion reference positions when the projected sections 4 and 6 of a module case are respectively inserted into the groove sections 5 and 7 of another module case. The projected section 4 of a module case can be inserted into the groove section 5 of another module case for example by positioning both modules so that the V-shaped mark 24 on a module case is aligned with the triangular mark on another module and by inserting the projected section 4 into the groove section 5. 
     The connection operation of the module cases of the present invention is described below referring to FIGS. 2 and 3. 
     First, place two module cases so that the side wall 3a of a module case faces the side wall 3c of another module case and so that the pointed end of the V-shaped mark 24 of the former module case is aligned with the pointed end of the triangular mark 22 of the latter module case on a straight line (see FIG. 2), insert the engagement section 11 of the projected section 4 of the former module case into the groove section 5 of the latter module case and also insert rail-shaped section 10 of the projected section 4 of the former module case into the space between the upper and lower projected walls 120, 120 of the groove section 5 of the latter module case. Then slide one of the module cases so that the pointed end of the triangular mark 20 of the former module case is aligned with the pointed end of the triangular mark 22 of the latter module case. 
     By this sliding, the projected walls 120, 120 of the second-engagement sections 12 are pressure-fit or simply inserted into the groove spaces S of the first-engagement sections 11. In this way, both module cases are mechanically connected at the regular position when the pointed ends of the marks 20 and 22 are aligned with each other on a straight line (see FIG. 3). At the same time, the terminals 8a and 8b on the projected section 4 of the former module case are respectively connected to the terminals 8c and 8d on the groove section 5 of the latter module case. As a result, the solar cell devices in these module cases are electrically connected in parallel. 
     To connect the solar cell devices of the two module cases in series, insert the projected section 6 of the former module case into the groove section 7 of the latter module case and slide one of the module cases so that the engagement sections 11 and 12 are engaged with each other. 
     As a result, the terminals 9a and 9b are respectively connected to the terminals 9c and 9d. In this case, these module cases are connected to each other by using the triangular mark 21 and the V-shaped mark 25 of a module case and the triangular mark 23 of another module case. The connection method using these marks is omitted since it can be easily understood by reference to the above description. Having described the present invention as related to the embodiment described above, it is our intention that the invention be not limited by any of the details of description, but rather be construed broadly without departing from the spirit of the present invention. For example, the configurations and dimensions of the engagement sections provided on the projected section and the groove section of the module case can be changed in various forms, that is, the engagement sections 11 and 12 can have tapered surfaces for instance. 
     A round convex section (not shown) can be formed on the engagement surface, which forms the groove space S, of the first-engagement section 11 of the projected section, and a concave section mating with the convex section is formed on the engagement surface of the second-engagement section 12 so that the convex section is inserted into the concave section when the engagement sections 11 and 12 are engaged with each other. In this case, the engagement between the two modules is made stronger in the longitudinal direction as well as in the crosswise direction. 
     Furthermore, the projected sections and groove sections of the module cases can be changed variously. The marks can be represented by other shapes or symbols. The colors of the marks can also be changed according to the function and connection method even when the shapes of the marks remain unchanged. 
     Moreover, printed marks can be attached on the module cases. 
     As described above, the solar cell module of the present invention includes plural connected solar cell devices and has the projected sections and the groove sections on its side walls where the terminals of the solar cell devices are provided so that the first-engagement sections provided on the projected section of a module case are engaged with the second-engagement sections provided on the groove section of another module case and the terminals are connected to each other. Therefore, the solar cell module of the present invention has the following advantages: 
     (1) Plural modules can be connected mechanically and electrically at the same time. 
     (2) The connection section has a firm and secure construction and is highly resistant against forces applied to it after connection. 
     (3) Even when the connected modules are directed in the solar radiation direction by inclining them, subjected to vibration, or placed under other severe conditions, the firm connection of the modules is maintained and thus highly reliable electrical connection is obtained. 
     (4) The modules can be connected easily. Voltages with various electrical characteristics can be obtained by electrically connecting the modules as desired. In addition, the modules are superior in portability. 
     (5) Even when dust builds up on the groove sections of the module, dust is ejected when a module is slid into another module. Therefore, secure electrical connection is obtained. 
     (6) The insertion reference marks and the connection marks are provided on the solar cell modules to allow sequential connection of the modules. As a result, connection is made easy and incorrect or incomplete connection can be prevented. 
     Consequently, the present invention can provide a highly practical solar cell module.