Abstract:
A plate body is disposed on a plurality of arrayed batteries. A first terminal is provided with a first portion which is connected to one of the batteries, and a second portion which is connected to an electronic element. A cover member is attached onto the plate body in a first direction, to provisionally fix the first terminal on the plate body. The first terminal is provided with a tolerance compensator, which connects the first portion and the second portion while compensating a positional difference between the first portion and the second portion in the first direction.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to a battery connecting plate for connecting batteries mounted in an electric vehicle, and relates to an attachment structure of the same. 
     FIG. 7  shows a related-art battery connecting plate disclosed in Japanese Patent Publication No. 2000-333343A. 
   In a battery connecting plate  501 , a terminal  505  and a bus bar  509  are insertion-molded with a plate body  502 . The terminal  505  is screwed to the electrode of a battery. Also attached to the plate body  502  are pivotable covers  504 . 
   In such a structure, it is difficult to compensate the size tolerances for batteries when the connection work is performed. If the terminal  505  is used to compensate such size tolerance, a crack may occur in the terminal  505 . Furthermore, since an electronic element is soldered to an element mounting portion  510  of the terminal  505 , either the soldered portion may be peeled off or a crack may occur in the soldered portion. 
   SUMMARY OF THE INVENTION 
   It is therefore an object of the invention to provide an improved battery connecting plate and an attachment structure thereof that can compensate the size tolerance for batteries while avoiding the above problems such as the peeling of the solder on a terminal or cracks in the terminal. 
   In order to achieve the above object, according to the invention, there is provided a battery connecting plate, comprising; 
   a plate body, disposed on a plurality of arrayed batteries; 
   a first terminal, provided with a first portion which is connected to one of the batteries, and a second portion which is connected to an electronic element; and 
   a cover member, attached onto the plate body in a first direction, to provisionally fix the first terminal on the plate body, 
   wherein the first terminal is provided with a tolerance compensator, which connects the first portion and the second portion while compensating a positional difference between the first portion and the second portion in the first direction. 
   With this configuration, the positional difference between the battery and the electronic element are positively compensated by the tolerance compensator of the first terminals. Therefore, the battery connecting plate that is provided ensures that cracks in the first terminal will not occur. 
   Here, the battery connecting plate further comprises a fixation member, which fixes the first portion of the first terminal to the one of the batteries to thereby plenarily fixing the first terminal on the plate body. 
   Preferably, the first terminal comprises a terminal body and a flexible leg portion extended from the terminal body to serve as the tolerance compensator. 
   In this case, the positional difference between the battery and the electronic element can be accurately compensated by flexing the flexible leg portion of the first terminal. 
   Here, it is preferable that the terminal body is provided with the first portion, and the flexible leg portion is provided with the second portion. 
   In this case, cracks do not occur in the terminal body portion, and the electric connection of the battery to the electronic element via the first terminals is ensured for a long time period. 
   Preferably, the battery connecting plate further comprises a second terminal, to which the first terminal is electrically connected via the electronic element. 
   With this arrangement, when there is a change in a current flowing from the battery, the state of the battery can be detected by the electronic element positioned between the first terminal and the second terminal. 
   Here, it is preferable that the first terminal, the second terminal and the electronic element are electrically connected by soldering. 
   In this case, since the positional difference between the battery and the electronic element are appropriately compensated by the tolerance compensator of the first terminal, the solder connecting the first terminal and the electronic element is protected and is not peeled off. 
   Preferably, the cover member comprises: a first cover, which is disposed on the plate body to provide a predetermined position relative to the plate body at which the second portion of the first terminal is placed; and a second cover, which is attached onto the first cover in the first direction to provisionally fix the flexible leg portion between the first cover and the second cover. 
   With this configuration, the first terminal protected by the first cover and the second cover. 
   Preferably, the plate body is formed with a first stopper, which restricts a movement of the cover member in the first direction. 
   Preferably, the plate body is formed with a second stopper, which restricts a movement of the cover member in a second direction opposite to the first direction. 
   With the above configurations, it is prevented the cover member from dropping through the plate body. 
   Preferably, the electronic element is an overcurrent protection resister provided in accordance with a maximum output voltage of the one of the batteries. 
   With this arrangement, when a battery is charged, or a current is supplied by the battery, an abnormality, such as a battery overcurrent, can be detected by the overcurrent protection resistor. 
   Preferably, the battery connecting plate further comprises a conductive bus bar, which comprises: a first portion, connected to a first one of the batteries; a second portion, connected to a second one of the batteries; and a fulcrum portion, situated between the first portion and the second portion. 
   Here, the plate body is formed with a protrusion which supports the fulcrum portion such that the bus bar is allowed to move in a see-saws manner before the bus bar is fixed on the plate body. 
   Here, it is preferable that the fulcrum portion of the bus bar and the protrusion of the plate body are configured such that the first portion of the bus bar is separated from the plate body when the second portion of the bus bar is brought into contact with the plate body. 
   With this arrangement, when the batteries are electrically connected by the bus bar, the size tolerance of the batteries is positively compensat d by the bus bar. Therefore, each of the batteries is easily and accurately mounted on the plate body, and the batteries are appropriately connected by the bus bar. 
   With the above configurations, assembly of the batteries can be easily and rapidly performed, so that the efficiency of the battery assembling process can be improved. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above objects and advantages of the present invention will become more apparent by describing in detail preferred exemplary embodiments thereof with reference to the accompanying drawings, wherein: 
       FIG. 1  is a perspective view of a battery connecting plate according to a first embodiment of the invention; 
       FIG. 2  is a vertical cross-sectional view of the battery connecting plate; 
       FIG. 3  is a perspective view of a terminal mounted on the battery connecting plate; 
       FIG. 4  is an exploded perspective view of a battery connecting plate according to a second embodiment of the invention; 
       FIG. 5  is an enlarged vertical cross-sectional view of a portion where an electronic element is mounted on the battery connecting plate; 
       FIG. 6  is an enlarged perspective view of a battery connecting plate according to a third embodiment of the invention; and 
       FIG. 7  is a perspective view of a related-art battery connecting plate. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Preferred embodiments of the invention will be described below in detail with reference to the accompanying drawings. 
   While referring to  FIGS. 1 and 2 , the side on which a nut  100  is located, on a plate body  10  that constitutes a battery connecting plate  1 , is defined as an upper side, and the side of a base wall  10   b  that forms the plate body  10  is defined as a lower side. It should be noted, however, that in this specification the upper and lower sides are defined merely for the convenience of the explanation, and do not always match the side positioning when the battery connecting plate is actually employed. 
   In these figures, the battery connecting plate  1  according to a first embodiment roughly comprises the plate body  10  which is mounted on batteries  400  that are arranged both vertically and horizontally; terminals  60  which are mounted on the plate body  10  and electrically connect batteries  400  and electronic elements  210 ; and upper covers  20  and lower covers  30  which are used to attach the terminals  60  to the plate body  10 . 
   The vertical size tolerance of the thus arranged batteries  400  is defined as being about ±0.1 mm. In order to assemble these batteries  400  into a single unit, the plate body  10  is attached to these batteries  400 . 
   The plate body  10  includes the base wall  10   b ; a upright peripheral wall  10   a  formed around the outer edge of the base wall  10   b ; and upright guide walls  11 ,  11   i ,  11   j ,  11   k  and  11   m  formed on the base wall  10   b . These members are integrally formed by using a synthetic resin material. 
   Metallic bus bars  50 , which are plated with tin in order to provide improved anticorrosion, are held in respective storage portions along the guide walls  11 . The terminals  60  are guided along the guide walls  11   i  and are held in the storage portions wherein the bus bars  50  are located. The upper and lower covers  20  and  30  made of synthetic resin are guided along the guide walls  11   j  to the respective storage portions. 
   Each of the upper covers  20  is formed with a peripheral wall  21  having a substantially rectangular box shape, and a plurality of partition walls  22   a  and  22   b , which intersect with the peripheral wall  21  to define hollow storage portions  23   a  (see  FIG. 5 ). Further, each of the upper covers  20  is formed with through holes  23   c  communicated with the storage portions  23   a.    
   Each of the lower covers  30  includes: a peripheral wall  31  having a substantially rectangular box shape; partition walls  32   a  formed inside the peripheral wall  31  to define rectangular storage portions  33   a.    
   Voltage detectors can be employed as the electronic elements  210  and  220 . And specifically, overcurrent prevention resistors are employed as the electronic elements  210  and  22 . 
   The bus bars  50 , which electrically connect the batteries  400  in series via the terminals  60 , are mounted on the plate body  10 . For each of the bus bars  50 , a convex portion  58  is placed almost in the center thereof, and a pair of contact portions  51  are provided. 
   To form bent portions  58   a  and  58   b  of the convex portions  58  (see  FIG. 2 ), press machining, such as punching or bending, is performed with respect to a metal strip. With this structure, the rigidity of the curved convex portions  58  is increas d. Furthermore, a support portion  18  is projected from the plate body  10  so as to support the convex portion  58  of the bus bar  50 . 
   When the bus bar  50  is attached to the plate body  10 , and when the convex portion  58  of the bus bar  50  is aligned with the support portion  18  of the plate body  10 , one of the contact portions  51  of the bus bar  50  is brought into contact with the base wall  10   b  of the plate body  1 , while the other contact portion  51  of the bus bar  50  is separated from the base wall  10   b . That is, a little play is provided for the bus bars  50  when it is mounted on the plate body  10 . 
   With this arrangement, when the plate body  10  is employed and the batteries  400  are electrically interconnected via the bus bars  50 , the vertical size tolerance for the batteries  400  is positively compensated by the bus bars  50  provided with the play. Therefore, the plate body  10  can be easily and accurately mounted on the batteries  400 , while the electrical connection of the batteries is ensured by the bus bars  50 . 
   In the state before the bus bars  50  are fixed to the plate body  10  using tools, such as nuts  100 , at the convex portions  58  the bus bars  50  placed on the plate body  10  can move in a see-saws manner. With this arrangement, the vertical size tolerance of the batteries  400  and the attachment difference between the batteries  400  and the plate body  10  can be compensated. Further, pairs of holes  55  slight largely formed in the bus bars  50  also serve to compensate the size tolerance and the attachment difference for the batteries  400 . 
   As shown in  FIG. 2 , each of the nuts  100  includes a body  101  consisting of an integrally formed hexagonal prism and a flathead washer  103 . Internal threads  105  are formed for the body  101 , and electrodes  405  that serve as external threads are extended from main bodies  401  of the batteries  400 . Relative to the electrodes  405 , through holes  15 ,  55  and  65  are respectively formed in the base wall  10   b  of the plate body  10 , the contact portions  51  of the bus bar  50  and contact portions  61  of the terminals  60  (described later). 
   When the through holes  15 ,  55  and  65  are aligned and the electrodes  405  of the batteries  400  are inserted into these through holes, and when the nuts  100  having the internal threads  105  engage the electrodes  405  that serve also as the external threads, the plate body  10  is fixed to the batteries  400 , and the terminals  60  and the bus bar  50  are secured to the plate body  10 . 
   When the internal threads  105  of the nuts  100  completely engage the external threads  405  of the batteries  400 , the flathead washers  103  provided for the nuts  100  abut upon the terminal main bodies  61  on one side, while the flathead washers  103  on the other side abut upon the contact portions  51  of the bus bars  50 . Further, at this time, the convex portions  58  formed by bending the bus bars  50  are flexed slightly, and the paired contact portions  51  provided for the bus bars  50   a  are brought in contact with the base wall  10   b  of the plate body  10 . 
   As shown in  FIGS. 1 and 2 , the bus bars  50  are secured to the plate body  10  by retainers  14  which are provided on the guide walls  11 . While the power lines  80  are secured to the plate body  10  by the peripheral wall  10   a  and retainers  14   w  which are provided on the guide walls  11   k  and  11   m.    
   As shown in  FIG. 2 , each of the retainers  14  are is formed with a retaining face  14   a , a connecting face  14   b  and a contact slope  14   c . In association with the retainers  14 , engagement recesses  24  having contact faces  24   a  are provided on the peripheral walls  21  of the upper covers  20 . When the protruded retainers  14  are fitted with the engagement recesses  24 , the upper covers  20  are attached to the plate body  10 , as shown in  FIG. 1 . 
   Incidentally, since the retaining faces  14   a  of the retainers  14  is brought into contact with the contact faces  24   a  of the engagement recesses  24 , the upper covers  20  are securely held to the plate body  10 . Here, the terminals  60 , which are located between the plate body  10  and the upper covers  20 , are maintained in a temporarily assembled state with respect to the plate body  10 . 
   As shown in  FIG. 3 , each terminal  60 , includes: a roughly rectangular terminal body  67  formed with an elongated crank-shaped notch  67 ; and a elongated crank-shaped flexible leg  66  which extends outward from the terminal body  61 . As shown in  FIG. 2 , the vertical positional difference between the battery  400  and the electronic element  210  can be positively compensated by flexing the elongated flexible leg  66  of the terminal  60 . 
   The flexible leg  66  is extended, beginning with a root portion  66   b , through a straight portion  66   c , curved portions  66   d  and  66   e  and folded portions  66   f  and  66   g  to a distal end portion  66   a . A hole  66   h  having a small diameter is formed in the end portion  66   a , so that a lead terminal  216  of the electronic element  210  can be passed therethrough, while a large diameter through hole  65  is formed in the terminal body  61 , so that the electrode  405  of the battery  400  can be passed therethrough as described the above. 
   When the thus arranged terminals  60  are employed, the positional differences between the batteries  400  and the electronic elements  210  are positively compensated by the flexible legs  66  of the terminals  60 . Therefore, it is possible to prevent cracks in the terminals  60  from occurring. 
   A plurality of linearly chamfered portions  61   a  and  66   i  are respectively formed on the terminal body  61  and the flexible leg  66 . Chamfered portions may be formed roundly. The chaffered portions  61   a  and  66   i  are provided for the terminal  60  to prevent the concentration of stress on the terminal  60 , and also to prevent the occurrence of a problem wherein a worker handles the terminals  60  carelessly and is injured. The terminal  60  is formed by presswork, such as punching or bending, employed for a material metal plate. 
   Further, terminals  70  are located between the upper and lower covers  20  and  30 , and are connected to power lines  80 . Each power line  80  is wired on the plate body  10  while being guided along the peripheral wall  10   a , the continuous guide walls  11   k  and discrete guide walls  11   m  disposed between the guide walls  11   k.    
   As shown in  FIG. 2 , solder  300  is used to connect the lead terminal  216 , projecting out of a body  211  of each electronic element  210 , with the flexible leg  66  of each terminal  60 . More specifically, to perform the soldering, the lead terminals  216  are inserted through the small holes  66   h  which are formed in the distal ends  66   a  of the flexible legs  66 . On the other hand, the solder  300  is used also to connect the lead terminal  217  of the electronic element  210  to a distal end  77   a  of each terminal  70  (see also  FIG. 4 ). More specifically, to perform soldering, the lead terminals  227  are inserted through the small holes  77   h  that are formed in the distal ends  77   a  of the terminals  70 . With this arrangement, electrical connections are provided for the terminals  60  and  70 . 
   Since the vertical positional difference between the batteries  400  and the electronic elements  210  is positively compensated by the flexible legs  66  of the terminals  60 , it is prevented the solder  300  from peeling off the flexible legs  66  of the terminals  60 . 
   In this embodiment, various soldering methods are employed. However, the soldering operation can be performed quickly and easily in a case where the electronic elements  210  has been mounted in the upper covers  20  and the lower covers  30 . 
   According to these arrangements, when a current flowing from the batteries  400  is changed, the electronic elements  210  located between the terminals  60  and  70  can detect the status of the batteries  400 . 
   The electronic elements  210  are, for example, overcurrent prevention resistors for detecting changes in a current at the border current value of about 70 mA. 
   A PTC (Positive Temperature Coefficient) thermistor can be employed as the electronic element  210 . A characteristic of a PTC thermistor is that resistance in the is increased as the temperature rises, and according to this characteristic, the resistance is increased rapidly when the temperature of an element exceeds a specific value, so that a reduced current is output to reduce the temperature. To the contrary, since the resistance is sharply reduced as the temperature falls a little, the PTC thermistor is heated by supplying the current and the temperature is raised. Further, a PTC thermistor can cope specifically with the supply of electric power, and can be employed not only to detect temperatures but also to directly control the electric power supply. For the PTC thermistor, a self-controlling material is employed that can by itself suppress the heat generation temperature to a specific range. 
   An explanation will now be given for the use of a PTC thermistor to protect a battery or an electric device from an overcurrent. As the current flowing to a PTC thermistor is increased, Joule heat raises the temperature of the PTC thermistor. Therefore, through the function provided by the PTC thermistor, when the current flow exceeds a specific limit, in the PTC thermistor the resistance is increased to suppress or to out off the current. That is, when a PTC thermistor is used for overcurrent protection, it serves as a resistor having a fixed low resistance, but when an overcurrent is supplied to the PTC thermistor, the resistance is sharply increased to limit the current supply. Since the PTC thermistor employed for overcurrent protection acts as a fuse that can be easily recovered, it is handled as an overcurrent protection resistor. 
   Specifically, Posisters (trademark), by Murata Manufacturing Co., Ltd., that can cope with a predesignated voltage can be employed as the overcurrent prevention resistors  210  and  220 . Thus, when a maximum voltage of about 6 V is set for the battery  400 , an overcurrent prevention Posister of 6 V is employed as an overcurrent prevention resistor; when a maximum voltage of about 24 V is set for the battery  400 , an overcurrent prevention Posister of 24 V is employed; and when a maximum voltage of about 125 V is set for the battery  400 , an overcurrent prevention Posister of 125 V is employed. In addition, a normal current value and an abnormal current value are employed to determine which overcurrent prevention resistor to use for the battery  400 . 
   As shown in  FIG. 2 , cover holder  12  is formed on the plate body  10 . Th lower covers  30  are attached to a lower side of the cover holder  12 . The terminals  70  and the flexible legs  66  and the terminals  60  are located on the lower covers  30 . When the upper covers  20  are mounted from above the cover holders  12  in a condition that the terminals  70  and the distal ends  66   a  of the flexible legs  66  of the terminals  60  has been arranged, the terminals  60  and  70  are fixed to the plate body  10 . 
   Since the terminals  60  and  70  are located between the upper covers  20  and the lower covers  30 , these terminals  60  and  70  are protected by being enclosed by the upper and lower covers  20  and  30 . In addition, by using pressing portions  26   a  and  26   b , which are located at the lower portions of the upper covers  20 , the distal ends  66   a  of the flexible legs  66  of the terminals  60  and the distal ends  77   a  of the terminals  70  are securely held by the upper covers  20  and the lower covers  30 . 
   In this state, the soldering process performed for the lead terminal  216  of the electronic element  210  and the distal end  66   a  of the flexible leg  66  of the terminal  60 , and the soldering process performed for the lead terminal  217  of the electronic element  210  and the distal end  77   a  of the terminal  70  can be easily performed. Therefore, the efficiency of manufacturing process for the battery connecting plate  1  is improved, ft should be noted that the solder  300  is a brazing alloy containing tin and that it has a low melting point. 
   Stoppers  13  (see  FIG. 2 ) are projected at the four lower corners of each cover holder  12 . When the lower four corners of the peripheral wall  31  of the lower cover  30  are brought into contact with the stoppers  13 , the lower cover  30  is attached to the plate body  10  at a predetermined position. 
   Further, the stoppers  13  prevent the lower covers  30  from being dropped from the plate body and being lost. On the other hand, the retainers  14  located in the upper portion of the cover holders  12 , the lower covers  30  are prevented from slipping out of the top of the cover holders  12 . 
   As a second embodiment of the invention, the lower cover  30  may be replaced with a lower cover  130  shown in  FIG. 4 . The members substantially identical with those described in the first embodiment are designated by the same reference numerals. 
   In the lower cover  130 , retainers  34  each formed with a retaining face  34   a , a connecting face  34   b  and a contact slope  34   c  are provided in association with the engagement recesses  24  of the upper cover  20 . The retainers  34  are fitted with the engagement recesses  24  to retain the upper cover  20  on the plate body  10 , in place of the retainers  14  of the cover holder  12  in the first embodiment. 
   Here, the contact faces  24   a  of the engagement recesses  24  are brought into contact with the retaining faces  34   a  of the retainers  34 , so that the upper covers  20  are securely held by the lower covers  130 . 
   Alternatively, instead of the retainers  14  shown in  FIG. 2 , the retainers  34  having such a shape may be directly formed on the plate body  10 . 
   Further, the lower covers  30  or  130  may be integrally formed with the plate body  10 . More specifically, the same synthetic resin material may be employed to integrally form the plate body  10  and the lower covers  30  or  130 . 
   Instead of the continuous guide walls  11   k  provided in an encircled area T in  FIG. 1 , as a third embodiment of the invention, guide walls  111   k  shown in  FIG. 6  may be employed. In this case, the guide walls  111   k  are partially removed and the guide walls  111   k  are discretely arranged. With this arrangement, the guide walls  11   k  and  111   k  are separately provided by defining spaces  11   n  therebetween, so that the power lines  80  can be easily laid for the plate body  10 . Holes  11   p  are formed to permit the insertion of a tool for forming the retainers  14   w.    
   As shown in  FIG. 6 , each of the power lines  80  includes a conductor  81  formed by coiling soft copper lines, and an insulating sheath  82  of vinyl chloride for protecting the conductor  81 . Furthermore, as shown in  FIG. 1 , the twelve collected power lines  80  are folded at a pectinated portion  16 . The pectinated portion  16  is formed with projections  16   a  defining twelve grooves  16   b  therebetween which are associated with the twelve power lines  80 . 
   A synthetic resin cover holder  40  is attached to the pectinated portion  16  of the plate body  10 , and the twelve power lines  80  folded at the pectinated portion  16  are extended along the cover holder  40  and are bundled by a band  90  at a guide portion  19  formed for the plate body  10 . 
   As shown in  FIG. 4 , crimping is used attach and to electrically connect the power line  80  to a connecting portion  78  of each terminal  70 . That is, the power line  80  is caulked by crimping pieces provided with the connecting portion  78  of the terminal  70 , so that the electrical connection of the terminal  70  and the power line  80  is ensured. Different colors are designated for the sheath  82  of the power lines  80 , so that the individual power lines  80  can be identified at a glance. 
   A plate cover (not shown) is attached to the battery connecting plate  1  in  FIG. 1 . Further, a battery cell, consisting of the batteries  400 , assembled using the battery connecting plate  1  can be employed as a common battery, or as a fuel cell to be mounted in an electric vehicle. 
   According to the above described structure, the batteries  400  can be securely assembled using the battery connecting plate  1 , while the electric connection of the batteries  400  is easily and surely established by using the bus bars  50 . Incidentally, the terminals  60  connected to the electronic elements  210  are fixed to the electrodes  405  of the batteries  400 . 
   Although the present invention has been shown and described with reference to specific preferred embodiments, various changes and modifications will be apparent to those skilled in the art from the teachings herein. Such changes and modifications as are obvious are deemed to come within the spirit, scope and contemplation of the invention as defined in the appended claims.