Patent Publication Number: US-2023147180-A1

Title: Electric connection box

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This Non-provisional application claims priority of Japanese Patent Application No. 2021-184097 filed on Nov. 11, 2021, the entire contents of which are incorporated herein. 
     TECHNICAL FIELD 
     The present disclosure relates to an electric connection box. 
     BACKGROUND 
     In the related art, a vehicle is equipped with an electric connection box where an electronic component such as a relay is mounted. The vehicle equipped with the electric connection box may be involved in a flood or an accident, and a liquid such as water and seawater may flow into the electric connection box of such a vehicle. Such liquid inflow may result in a short circuit and a malfunction. 
     Japanese Patent Application Laid-Open Publication No. 2018-042356 discloses an electric connection box in which a partition wall for partitioning between high- and low-voltage circuit regions is configured to be higher than the peripheral wall of a housing having the high-and low-voltage circuit regions. 
     According to Japanese Patent Laid-Open Publication No. 2018-042356, it is possible to avoid a short circuit occurring in both circuit regions via water even in a case where a liquid flows in and remains in the housing. 
     Once the liquid flows into the electric connection box, it takes a considerable amount of time to completely drain the liquid. Besides, meanwhile, the risks of short circuit, malfunction, and the like still remain. Accordingly, it is desirable to monitor liquid inflow into the electric connection box and take countermeasures in advance. 
     However, the electric connection box of Japanese Patent Laid-Open Publication No. 2018-042356 focuses only on post-liquid inflow risks, without devising anything as to liquid inflow monitoring and proactive measures against liquid inflow, and is incapable of solving the above problems. 
     SUMMARY 
     The present disclosure has been made in view of such circumstances, and an object of the present disclosure is to provide an electric connection box with which proactive measures can be taken by liquid inflow monitoring. 
     An electric connection box according to an embodiment of the present disclosure includes a housing where an electronic component is mounted. The housing is provided with a detection part detecting liquid inflow. 
     According to the present disclosure, proactive measures can be taken by monitoring liquid flow into the electric connection box. 
     The above and further objects and features will more fully be apparent from the following detailed description with accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view of an electric connection box according to the present embodiment. 
         FIG.  2    is a partial perspective view of a lower case of the electric connection box of the present embodiment. 
         FIG.  3    is a partial plan view of the lower case of the electric connection box of the present embodiment. 
         FIG.  4    is a partial cross-sectional view of the lower case taken along line IV-IV of  FIG.  3   . 
         FIG.  5    is a partial cross-sectional view illustrating the internal configuration of a storage recess of a detection part. 
         FIG.  6    is an explanatory diagram conceptually describing a circuit configuration for notifying a driver of an inflow liquid detection result of the detection part. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     First, an aspect of implementation of the present disclosure will be listed and described. In addition, at least a part of the embodiment described below may be combined in any manner. 
     First Aspect 
     An electric connection box according to a first aspect of the present disclosure includes a housing where an electronic component is mounted, in which the housing includes a detection part detecting inflow of a liquid. 
     In the first aspect, the detection part detecting the liquid inflow is provided, and thus the liquid inflow can be monitored and countermeasures can be taken in advance or early against the flow of the liquid into the housing. 
     Second Aspect 
     In the electric connection box according to a second aspect of the present disclosure, the detection part has a storage recess having an inlet for the liquid and storing the liquid flowing in from the inlet and a detection needle disposed in the storage recess. 
     In the second aspect, at the detection part, the liquid flowing into the storage recess through the inlet is stored in the storage recess and detected by the detection needle. Since the liquid flowing in is stored and detected, even a small amount of liquid can be detected. 
     Third Aspect 
     In the electric connection box according to a third aspect of the present disclosure, the storage recess has a curved bottom surface guiding the liquid to an inner side wall facing the inlet, and the detection needle is disposed near the inner side wall. 
     In the third aspect, the liquid flowing into the storage recess through the inlet is guided by the curved bottom surface to the inner side wall where the detection needle is disposed and stored. Accordingly, even a small amount of liquid can be detected. 
     Fourth Aspect 
     In the electric connection box according to a fourth aspect of the present disclosure, a liquid drain hole for the liquid is provided in the inner side wall. 
     In the fourth aspect, the liquid that is greater than the amount necessary for the detection by the detection needle is discharged out of the housing by the liquid drain hole. Accordingly, it is possible to forestall the liquid being excessively stored in the storage recess and flowing into the housing over the storage recess. 
     Fifth Aspect 
     In the electric connection box according to a fifth aspect of the present disclosure, a width on the inner side wall is smaller than a width on the inlet in the storage recess. 
     In the fifth aspect, since the width on the inner side wall side is smaller than the width on the inlet side in the storage recess, the liquid surface rise in the vicinity of the inner side wall where the detection needle is disposed accelerates. Accordingly, the detection needle is capable of early liquid inflow detection. 
     Sixth Aspect 
     In the electric connection box according to a sixth aspect of the present disclosure, the liquid drain hole is provided at a position separated from the curved bottom surface by a distance two to four times as long as a gap between the detection needle and the curved bottom surface. 
     In the sixth aspect, since the liquid drain hole is provided at the position separated from the curved bottom surface by a distance two to four times as long as the gap between the detection needle and the curved bottom surface, it is possible to discharge out of the housing the liquid greater than the amount necessary for the detection while reliably executing the detection by the detection needle. 
     Seventh Aspect 
     The electric connection box according to a seventh aspect of the present disclosure further includes a bus bar connected to the electronic component, in which the detection needle is formed integrally with the bus bar. 
     In the seventh aspect, since the detection needle is formed integrally with the bus bar, a detection result of the detection needle can be acquired via the bus bar and a circuit configuration for the detection result of the detection needle is facilitated. 
     An electric connection box according to an embodiment of the present disclosure will be described below with reference to the drawings. It should be noted that the present disclosure is not limited to the exemplifications. The present disclosure is defined by the scope of the claims and is intended to include every modification within the meaning and scope equivalent to the scope of the claims. 
     Hereinafter, the present embodiment will be described by taking as an example an electronic component-mounted vehicular electric connection box. 
       FIG.  1    is a perspective view of an electric connection box  100  according to the present embodiment. 
     The electric connection box  100  is attached to the outside of, for example, an electric vehicle (EV) battery pack. The electric connection box  100  includes a housing  50  where an electronic component such as a fuse and a relay  400  is mounted. 
     The housing  50  is made of, for example, resin or metal and includes a lower case  52  and an upper case  51  covering the lower case  52 . The housing  50  is, for example, attached to the battery pack such that a bottom plate  521  of the lower case  52  faces the battery pack. The bottom plate  521  has an uneven shape in the thickness direction. 
     The lower case  52  has the shape of a flat housing with one surface open. A plurality of ribs are formed and a plurality of pedestals are formed inside the lower case  52 . A bus bar, an electronic component (not illustrated), and so on are attached to the pedestal. 
     In addition, the lower case  52  is provided with a detection part  10  detecting the flow of a liquid such as rainwater and seawater into the battery pack or the electric connection box  100 . 
       FIG.  2    is a partial perspective view of the lower case  52  of the electric connection box  100  of the present embodiment, and  FIG.  3    is a partial plan view of the lower case  52  of the electric connection box  100  of the present embodiment.  FIGS.  2  and  3    illustrate the detection part  10  and the surroundings of the detection part  10  in the lower case  52  with the upper case  51  removed. 
     The detection part  10  has a storage recess  11  storing a liquid flowing into the electric connection box  100  from the outside (hereinafter, referred to as inflow liquid) and a pair of detection needles  121  and  131  disposed in the storage recess  11 . 
     The storage recess  11  is provided in the vicinity of one side wall of the lower case  52 . The storage recess  11  communicates with the outside of the lower case  52  through an inlet  15  provided in the one side wall. In other words, the storage recess  11  has the inlet  15  communicating with the outside of the lower case  52 . Accordingly, before the inflow liquid starts to flow into the electric connection box  100 , the inflow liquid first flows into the storage recess  11  through the inlet  15 . 
     The storage recess  11  is substantially trumpet-shaped in a plan view and has three side walls erected inside the bottom plate  521  of the lower case  52 . The storage recess  11  has a inner side wall  112  provided on the back side far from the inlet  15  and facing the inlet  15  and a first side wall  113  and a second side wall  114  continuously provided on both sides of the inner side wall  112  and disposed so as to substantially face each other. Each of the inside ends of the first side wall  113  and the second side wall  114  is provided so as to be continuous with the inner side wall  112  as described above. The outside ends of the first side wall  113  and the second side wall  114  configure the edge of the inlet  15 . 
     The second side wall  114  extends straight from the inner side wall  112  toward the one side wall of the lower case  52 . On the other hand, the end portion of the first side wall  113  that is close to the one side wall of the lower case  52  is curved to the outside, that is, in the direction away from the second side wall  114 . Accordingly, the gap between the first side wall  113  and the second side wall  114  widens toward the inlet  15 . In other words, in the storage recess  11 , the width on the inner side wall  112  is smaller than the width on the inlet  15 . In other words, the dimension of the storage recess  11  in the direction intersecting the facing direction of the inlet  15  and the inner side wall  112  is shorter on the inner side wall  112  than at the inlet  15 . 
     A bottom surface  111  (curved bottom surface) of the storage recess  11  is curved and guides the inflow liquid flowing into the storage recess  11  through the inlet  15  to the inner side wall  112 .  FIG.  4    is a partial cross-sectional view of the lower case  52  taken along line IV-IV of  FIG.  3   . 
     As can be seen from  FIG.  4   , in a cross-sectional view, the bottom surface  111  has a flat end portion near the inner side wall  112  and an upwardly curved end portion near the inlet  15 . Accordingly, the flow of the inflow liquid flowing into the storage recess  11  through the inlet  15  can be strengthened and the inflow liquid easily flows to the inner side wall  112 . 
     In addition, the detection part  10  has a liquid drain hole  14  for discharging, to the outside of the electric connection box  100 , the inflow liquid that is greater than the amount necessary for the detection needles  121  and  131  to detect the inflow liquid. The liquid drain hole  14  is formed in the inner side wall  112 . 
       FIG.  5    is a partial cross-sectional view illustrating the internal configuration of the storage recess  11  of the detection part  10 . 
     The inner side wall  112  includes a lower inner side wall  112   a  provided close to the bottom surface  111  and an upper inner side wall  112   b  positioned farther from the bottom surface  111  than the lower inner side wall  112   a.  The lower inner side wall  112   a  is smaller than the upper inner side wall  112   b  in up-down-direction dimension, and the lower inner side wall  112   a  is provided so as to be continuous with the bottom surface  111 . The upper inner side wall  112   b  is provided away from the lower inner side wall  112   a  in the direction away from the inlet  15  and above the upper end of the lower inner side wall  112   a.    
     In this manner, the inner side wall  112  includes the two parts of the lower inner side wall  112   a  and the upper inner side wall  112   b,  the upper inner side wall  112   b  is separated from the lower inner side wall  112   a  in the facing direction of the inlet  15  and the inner side wall  112 , and thus a substantially rectangular gap is formed between the lower inner side wall  112   a  and the upper inner side wall  112   b.  Such a gap corresponds to the liquid drain hole  14 . As described above, the liquid drain hole  14  communicates with the outside of the electric connection box  100 . 
     In addition, in order to prevent the excessive inflow liquid that is equal to or greater than the amount necessary for the inflow liquid detection from storing in the storage recess  11 , in this configuration, the lower inner side wall  112   a  is smaller than the upper inner side wall  112   b  in up-down-direction dimension (hereinafter, referred to as up-down dimension) as described above. In  FIG.  4   , L denotes the up-down dimension of the lower inner side wall  112   a.    
     In other words, the up-down dimension L of the lower inner side wall  112   a  defines the liquid surface level of the inflow liquid storing in the storage recess  11 . In a case where the up-down dimension L of the lower inner side wall  112   a  is too short, the liquid surface level of the inflow liquid is too low, and thus the inflow liquid detection by the detection needles  121  and  131  is inaccurate. On the other hand, in a case where the up-down dimension L of the lower inner side wall  112   a  is too long, the liquid surface level of the inflow liquid is too high, and thus the inflow liquid in the storage recess  11  may flow into the lower case  52  by splashing over the first side wall  113  or the second side wall  114 . 
     In view of such a problem, it is desirable that the up-down dimension L of the lower inner side wall  112   a  is two to four times a gap G between the lower ends of the detection needles  121  and  131  and the bottom surface  111  (see  FIG.  4   ). In other words, the liquid drain hole  14  is provided above the bottom surface  111  by a distance two to four times as long as the gap G between the detection needles  121  and  131  and the bottom surface  111 . 
     The detection needles  121  and  131  are disposed in the vicinity of the inner side wall  112  in the storage recess  11 . The detection needles  121  and  131  are disposed with an insulation distance in the facing direction of the inlet  15  and the inner side wall  112 . The detection needles  121  and  131  are substantially strip-shaped, extend in the up-down direction, and are parallel to each other (see  FIG.  4   ). The detection needles  121  and  131  have the same shape, and the lower end portions thereof are reduced in width. The lower ends of the detection needles  121  and  131  are provided apart by the gap G from the bottom surface  111  as described above. 
     Bus bars  12  and  13  connected to the electronic component mounted on the electric connection box  100  are disposed in the vicinity of the storage recess  11  in the lower case  52 . The detection needles  121  and  131  are formed integrally with the bus bars  12  and  13 , respectively. The detection needle  121  is formed integrally with the bus bar  12 , and the detection needle  131  is formed integrally with the bus bar  13  (see  FIGS.  2  and  3   ). The bus bars  12  and  13  are made of, for example, a conductive metal plate material. 
     Specifically, although the detection needles  121  and  131  are disposed apart from the bus bars  12  and  13 , respectively, the upper end of the detection needle  121  is connected to the bus bar  12  by a strip-shaped plate member  122  and the upper end of the detection needle  131  is connected to the bus bar  13  by a strip-shaped plate member  132 . 
     The detection part  10  configured as described above detects the flow of the inflow liquid into the electric connection box  100 . For example, when the inflow liquid flows into the electric connection box  100 , the inflow liquid flows into the storage recess  11  through the inlet  15  in the side wall of the lower case  52  and stores in the storage recess  11 . The detection needles  121  and  131  are immersed in the inflow liquid by the amount of the inflow liquid that is stored in the storage recess  11  increasing and the liquid surface level of the inflow liquid exceeding the gap G between the bottom surface  111  and the detection needles  121  and  131 . At this time, the resistance value between the detection needles  121  and  131 , that is, the resistance value between the bus bars  12  and  13  decreases, and thus the flow of the inflow liquid into the electric connection box  100  can be detected by monitoring the resistance value between the bus bars  12  and  13 . 
     In other words, in the electric connection box  100 , the detection part  10  monitors (detects) the flow of the inflow liquid into the electric connection box  100 , and thus countermeasures against inflow of the inflow liquid can be quickly taken based on the monitoring result of the detection part  10 . 
     The inflow liquid detection result of the detection part  10  may be output to the outside (e.g. ECU) and the driver of a vehicle equipped with the electric connection box  100  of the present embodiment may be notified of the result. 
       FIG.  6    is an explanatory diagram conceptually illustrating a circuit configuration for notifying a driver of the inflow liquid detection result of the detection part  10 . 
     An ECU  200  is connected to the electric connection box  100  (detection part  10 ) and an instrument panel  300 . For example, the instrument panel  300  is provided with a warning light indicating the flow of the inflow liquid into the electric connection box  100  or the battery pack. The ECU  200  monitors a change in resistance value between the bus bars  12  and  13  (detection needles  121  and  131 ) based on the detection result output from the detection part  10  and causes the warning light on the instrument panel  300  to flicker in accordance with the monitoring result. 
     Specifically, the ECU  200  monitors the resistance value between the bus bars  12  and  13  and, in a case where such a resistance value decreases to or below a predetermined threshold, causes the warning light on the instrument panel  300  to flicker to notify the driver of the inflow of the inflow liquid. 
     In the electric connection box  100  of the present embodiment, the detection part  10  communicates with the outside through the inlet  15  formed in the side wall of the lower case  52  as described above, and thus the inflow liquid easily flows into the storage recess  11  of the detection part  10 . Accordingly, the inflow liquid can be detected early immediately before the inflow liquid flows into the electric connection box  100 . 
     In addition, as described above, in the storage recess  11  of the electric connection box  100 , the width on the inner side wall  112  is smaller than the width on the inlet  15 . Accordingly, in a case where the inflow liquid flows into the storage recess  11 , the liquid surface rise in the vicinity of the inner side wall  112 , that is, in the vicinity of the detection needles  121  and  131  accelerates and the detection needles  121  and  131  are capable of quickly detecting the inflow liquid even at a small inflow liquid amount. 
     Further, as described above, the bottom surface  111  of the storage recess  11  is curved and the inflow liquid flowing into the storage recess  11  is guided to the inner side wall  112 . Accordingly, the liquid surface rise in the vicinity of the detection needles  121  and  131  further accelerates. 
     In addition, in the electric connection box  100 , the detection part  10  has the liquid drain hole  14 , and thus the inflow liquid that is greater than the amount necessary for the inflow liquid detection is discharged out of the electric connection box  100  through the liquid drain hole  14 . Accordingly, no excessive inflow liquid storage occurs in the storage recess  11  and it is possible to prevent the inflow liquid in the storage recess  11  from flowing into the lower case  52  over the first side wall  113  or the second side wall  114  when, for example, the electric connection box  100  vibrates. 
     In addition, in the electric connection box  100 , the detection needles  121  and  131  are formed integrally with the bus bars  12  and  13 , respectively. Accordingly, a change in resistance value between the detection needles  121  and  131  can be confirmed via a change in resistance value between the bus bars  12  and  13 . Accordingly, the circuit configuration for outputting the inflow liquid detection result of the detection part  10  is easy and simple. 
     The embodiment disclosed this time is an exemplification in every respect and should be considered not restrictive. The scope of the present disclosure is defined not by the meaning described above but by the scope of the claims and is intended to include every modification within the meaning and scope equivalent to the scope of the claims. 
     It is to be noted that, as used herein and in the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise. 
     It is to be noted that the disclosed embodiment is illustrative and not restrictive in all aspects. The scope of the present invention is defined by the appended claims rather than by the description preceding them, and all changes that fall within metes and bounds of the claims, or equivalence of such metes and bounds thereof are therefore intended to be embraced by the claims.