Patent Publication Number: US-2023164940-A1

Title: Electrical box

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present disclosure claims priority to Chinese Patent Application No. 202122903211.4, titled “ELECTRICAL BOX”, filed on Nov. 24, 2021, the content of which is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     The present document relates to an electrical box, and in particular to an electrical box for a vehicle. 
     BACKGROUND 
     A vehicle may comprise various devices that require power (i.e., electrical devices) for various applications. For example, various sensors may be mounted on the vehicle for safety purposes, driving assistance, or facilitating autonomous driving, and the sensors mounted on the vehicle may acquire sensor data of various aspects around the vehicle. The vehicle may also be equipped with a computing apparatus for processing the sensor data, and the sensor data processing result may be used to safely operate the vehicle. In order to acquire and process the sensor data, the sensors, computing apparatus and other devices in the vehicle require power. For the safety of the vehicle, it is necessary to consider the problem of power supply to the electrical devices when the power source fails. 
     SUMMARY 
     The present disclosure provides an electrical box, wherein the electrical box may be connected between a power source and an electrical device and supports redundant power supply to the electrical device. 
     In one aspect, the present disclosure provides an electrical box comprising: a first circuit comprising a first power input interface at one end of the first circuit and a first power output interface at another end of the first circuit; a second circuit comprising a second power input interface at one end of the second circuit and a second power output interface at another end of the second circuit; and a third circuit electrically connected to the first and second circuits and comprising a third power output interface. 
     In another aspect, the present disclosure provides an electrical box comprising: a first circuit configured to provide power from a first power source to a first group of electrical devices; a second circuit configured to provide power from a second power source to a second group of electrical devices; and a third circuit configured to provide the power from the first power source and the power from the second power source to a third group of electrical devices. 
     The electrical box provided by the present disclosure comprises a plurality of circuits that can provide power from a plurality of power sources to an electrical device to support redundant power supply to the electrical device. When one power source fails, the electrical box can provide power from additional power sources to the electrical device, so as to ensure that the apparatus comprising the electrical device continues to operate safely (for example, the vehicle comprising the electrical device continues to travel safely or has sufficient power to travel to a safe location). 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings illustrate the exemplary embodiments and constitute a part of the specification, and, together with the text description of the specification, are provided to illustrate the exemplary implementations of the embodiments. It is obvious that the accompanying drawings described below are only some embodiments of the utility model. For those of ordinary skilled in the art, other drawings can be derived from the accompanying drawings without creative effort. Throughout the accompanying drawings, identical reference numerals designate similar, but not necessarily identical, elements. 
         FIG.  1    is a schematic structural diagram of an electrical box according to an exemplary embodiment; 
         FIG.  2    is a schematic diagram of supplying power to an electrical device by a power source through an electrical box according to an exemplary embodiment; 
         FIG.  3    is a schematic structural diagram of an electrical box according to another exemplary embodiment; 
         FIG.  4 A  is a schematic diagram of the mounting process of the cover plate of an electrical box according to an exemplary embodiment; 
         FIG.  4 B  is an enlarged view of the portion shown in block A in  FIG.  4 A ; and 
         FIG.  5    is a top view of an electrical box with the cover plate mounted according to an exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     In order to make the purposes, technical schemes and advantages of the utility model more apparent, the utility model will be described in further detail with reference to the accompanying drawings. It is obvious that the described embodiments are only part of the embodiments of the utility model rather than all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the utility model. 
     In the present disclosure, unless otherwise specified, the term “plurality” means two or more. In the present disclosure, unless otherwise specified, the terms “first”, “second”, and the like are used for distinguishing between similar objects, and are not intended to limit position relationships, timing relationships, or importance relationships thereof. It is to be understood that the terms used in this manner are interchangeable under appropriate circumstances so that the embodiments of the utility model described herein can be implemented in other manners in addition to those illustrated or described herein. 
     Moreover, the terms “comprise” and “have” and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to the explicitly listed steps or units, but may comprise other steps or units that are not explicitly listed or are inherent in the process, method, system, product or device. 
     With the development of the vehicle electronic and electrical system and autonomous driving, the safety level requirement for the vehicle electronic and electrical system is higher and higher. Therefore, part of the electronic and electric system begin to be subjected to redundancy design, and meanwhile there is also a need for redundant power supply. After considering factors such as cost and weight, the inventor also thinks that it is not necessary to perform redundant design on all electrical devices in the whole system, and only some electrical devices (these electrical devices are also called primary electrical devices, and the redundancy of the primary electrical devices is also called secondary electrical devices) may be subjected to redundant design, while other electrical devices are not subjected to redundant design (these electrical devices are also called shared electrical devices). In this way, the electrical devices may be classified into primary electrical devices, secondary electrical devices (i.e., the redundancy of the primary electrical devices) and shared electrical devices, and the power supply thereto is designed according to the classification of the electrical devices. The primary electrical devices may be powered by the primary power source, the secondary electrical devices may be powered by the secondary power source, and the shared electrical devices may be powered by both the primary power source and the secondary power source. Based on this concept, the present disclosure provides an electrical box that may be mounted on a vehicle (e.g., an autonomous vehicle) to support redundant power supply. 
       FIG.  1    is a schematic structural diagram of an electrical box according to an exemplary embodiment. As shown in  FIG.  1   , the electrical box  100  comprises a base plate  101 . Various elements may be mounted or fixed on a surface of the base plate  101 . The base plate has mounting holes at its periphery. For example, in  FIG.  1   , the mounting holes of the base plate are positioned at four corners. Through these mounting holes, the base plate may be fixed on the vehicle, thereby the electrical box may be fixed on the vehicle. The base plate  101  may have a shape such as a rectangle, a square, a triangle, a pentagon, a hexagon, a circle or an ellipse, or the shape of the base plate may be designed according to the mounting position of the electrical box on the vehicle. 
     As shown in  FIG.  1   , one or more electric conductors, such as electric conductors  112 ,  114 ,  122 ,  124  and  152 , are mounted on a surface of the base plate  101 . To reduce space occupation for facilitating the miniaturization of the electrical box, one or more or all of the electric conductors may be composed of metal strips and not coated with an insulating material. The cross-section of the metal strip may be rectangular, and the width of the metal strip may be at least 5 times, or at least 10 times, or at least 20 times the thickness. Because the metal strip is not coated with an insulating material, the surface of the metal strip may be subjected to anti-oxidation treatment in order to prevent the metal strip from being oxidized. For example, the metal strip may be a copper strip, and the surface of the copper strip may be tin-plated. 
     The electric conductors may be electrically connected using a protection element, for example, electric conductors  112  and  114  are electrically connected to each other using a protection element  116 , electric conductors  122  and  124  are electrically connected to each other using a protection element  126 , and the protection elements may prevent overcurrent. For example, the protection element  116  may electrically disconnect the electric conductors  112  and  114  when the current flowing through the electric conductors  112  and  114  (or the current flowing through the protection element  116 ) exceeds a first predetermined threshold. Similarly, the protection element  126  may electrically disconnect the electric conductors  122  and  124  when the current flowing through the electric conductors  122  and  124  (or the current flowing through the protection element  126 ) exceeds a second predetermined threshold. The first predetermined threshold and the second predetermined threshold may be the same or different (for example, the first predetermined threshold is greater than the second predetermined threshold, such as the first predetermined threshold is 125 amps and the second predetermined threshold is 60 amps). 
     One example of the protection elements is a fuse (e.g., a slow blow fuse). The fuse will blow itself to cut off the current when the current rises abnormally above a predetermined threshold. Another example of the protection elements is a switch with a current detector that opens when the current detector detects that the current rises abnormally above the predetermined threshold. 
     As shown in  FIG.  1   , the electric conductor  112  has an opening at one end and the end forms a power input interface  113 . The other end of the electric conductor  112  is electrically connected to the protection element  116 . The power source may be electrically connected to the power input interface  113  via a wire, and the wire may be fixed relative to the electric conductor  112  via the opening in the electric conductor  112 . The electric conductor  114  has an opening at one end and the end forms a power output interface  115 . The other end of the electric conductor  114  is electrically connected to the protection element  116 . The electrical devices may be electrically connected to the power output interface  115  via a wire, and the wire may be fixed relative to the electric conductor  114  via the opening in the electric conductor  114 . The electric conductor  122  has an opening at one end and the end forms a power input interface  123 . The other end of the electric conductor  122  is electrically connected to the protection element  126 . The power source may be electrically connected to the power input interface  123  via a wire, and the wire may be fixed relative to the electric conductor  122  via the opening in the electric conductor  122 . The electric conductor  124  has an opening at one end and the end forms a power output interface  125 . The other end of the electric conductor  124  is electrically connected to the protection element  126 . The electrical devices may be electrically connected to the power output interface  125  via a wire, and the wire may be fixed relative to the electric conductor  124  via the opening in the electric conductor  124 . The electric conductor  152  is a ground line, forms a ground interface and has a plurality of openings  153 . The ground line in the power source may be electrically connected to the electric conductor  152  via a wire, and the wire may be fixed relative to the electric conductor  152  via the openings in electric conductor  152 . 
     In some embodiments, the openings in the electric conductors (e.g., the electric conductor  112 , the electric conductor  114 , the electric conductor  122 , the electric conductor  124  and the electric conductor  152 ) shown in  FIG.  1    may be round holes. In some embodiments, the electric conductors (e.g., the electric conductor  112 , the electric conductor  114 , the electric conductor  122 , the electric conductor  124  and the electric conductor  152 ) shown in  FIG.  1    may not comprise openings, instead recesses may be formed on both sides of the electric conductors at locations corresponding to the openings, or protrusions (e.g., cylindrical protrusions) may be formed on the surface of the electric conductors. By comprising an opening, a recess or a protrusion in the power input interface or the power output interface of the electric conductor, the electrical connection of the power input interface or the power output interface to the power source or the electrical device may be enhanced, and the corresponding wires for the electrical connection may be fixed. 
     In some embodiments, the electric conductor  112 , the electric conductor  114 , the electric conductor  122 , the electric conductor  124  and the electric conductor  152  have mounting holes (e.g., mounting hole  139 ) through which the electric conductors may be fixed on the base plate  101 . 
     As shown in  FIG.  1   , the electrical box  100  further comprises electric conductors  132  and  134  and a power output interface  162 . One end of each of the electric conductors  132  and  134  is electrically connected to the electric conductors  112  and  122 , respectively, and the other ends thereof may be electrically connected to the power output interface  162  through, for example, a protection element, so that the electric conductors  112  and  122  are electrically connected to the power output interface  162 . Although the electric conductors  132  and  134  are electrically connected to the electric conductors  112  and  122  in  FIG.  1   , respectively, the electric conductors  132  and  134  may also be electrically connected to the electric conductors  114  and  124 , respectively. The electric conductors  132  and  134  may be wires (e.g., copper wires) that may be round or oval in cross-section and that have a surface coated with an insulating material. The power output interface  162  may be various connectors (e.g., a vehicle-scale connector) for electrically connecting to electrical devices. 
     As described above, the power input interface  113  and the power input interface  123  may be electrically connected to a power source. The power output interface  115 , the power output interface  125  and the power output interface  162  may be electrically connected to electrical devices. Examples of the power source comprise a generator (e.g., the generator in a vehicle) and a battery. Examples of the electrical devices comprise a sensor system, a computing apparatus and/or a control apparatus. 
     In some embodiments, the electrical box  100  further comprises a safety box  168 , wherein the safety box may have one or more protection elements therein for preventing overcurrent. The safety box is connected between the electric conductors  132  and  134  and the power output interface  162 , and is electrically connected to the power output interface  162  through the electric conductors  135  and  137 . The electric conductors  135  and  137  may be wires (e.g., copper wires) that may be round or oval in cross-section and that have a surface coated with an insulating material. The safety box may further have one or more anti-reverse elements to prevent reverse current. The safety box  168  has, for example, mounting holes on both sides, and the safety box  168  may be fixed on the base plate  101  through the mounting holes. 
     In some embodiments, the electrical box  100  further comprises a voltage converter  164  for converting, i.e., stepping up or stepping down, the voltage of the power source. The voltage converter  164  has one or more mounting portions  165 , wherein the mounting portions have mounting holes therein, and the voltage converter  164  is fixed on the base plate  101  through the mounting holes. The voltage converter  164  has an input electrically connected to the electric conductor  136  and an output electrically connected to the electric conductor  138 . The voltage converter  164  may be electrically connected to the safety box  168  through electric conductors  136  and  138 , such that power from the power source is provided to the voltage converter  164  via the electric conductors  132  and  134  and the safety box  168 , and power converted (i.e., stepped-up or stepped-down) by the voltage converter  164  is provided to the power output interface  162  via the safety box  168 . The electric conductors  136  and  138  may be wires (e.g., copper wires) that may be round or oval in cross-section and that have a surface coated with an insulating material. 
     The electric conductor  156  is also shown in the dashed line in  FIG.  1    for electrically connecting the voltage converter  164  to the electric conductor  152  as the ground line. The safety box  168  and the power output interface  162  may also be electrically connected to the electric conductor  152  by electric conductors (not shown). The electric conductors connected to the electric conductor  152  may be wires (e.g., copper wires) that may be round or oval in cross-section and that have a surface coated with an insulating material. 
     In some embodiments, the electrical devices may be divided into a plurality of groups, such as a first group of electrical devices, a second group of electrical devices and a third group of electrical devices. The power source may comprise a plurality of power sources (e.g., two). The power input interfaces are electrically connected to different power sources. The power output interfaces are electrically connected to different groups of electrical devices. 
     In some embodiments, one group of electrical devices are used as the redundancy of the other group of electrical devices, for example, the second group of electrical devices are used as the redundancy of the first group of electrical devices, and the two power sources are redundant to each other. In this case, the first group of electrical devices are also called primary electrical devices, the second group of electrical devices are also called secondary electrical devices, and the two power sources that are redundant to each other are called a primary power source and a secondary power source, respectively. The primary electrical devices are powered by the primary power source, and the secondary electrical devices are powered by the secondary power source. When the primary power source or the primary electrical devices fail, the primary electrical devices stop operating, and the secondary electrical devices are powered by the secondary power source to replace the primary electrical devices to operate. The third group of electrical devices may be powered jointly by the primary power source and the secondary power source, and in this sense, the third group of electrical devices are also called shared electrical devices. 
     As shown in  FIG.  1   , the primary power source may be electrically connected to the electric conductor  112  through the power input interface  113 , the electric conductor  112  may be electrically connected to the electric conductor  114  through the protection element  116 , and the electric conductor  114  may be electrically connected to the primary electrical devices through the power output interface  115 . The secondary power source may be electrically connected to the electric conductor  122  through the power input interface  123 , the electric conductor  122  may be electrically connected to the electric conductor  124  through the protection element  126 , and the electric conductor  124  may be electrically connected to the secondary electrical devices through the power output interface  125 . The primary power source and the secondary power source are electrically connected to the electric conductor  112  and the electric conductor  122  through the power input interface  113  and the power input interface  123 , respectively, then electrically connected to the power output interface  162  through the electric conductors  132  and  134  and the safety box  168 , and electrically connected to the shared electrical devices through the power output interface  162 . 
     When the primary electrical devices fail, causing the current in the electric conductor  112  or the electric conductor  114  (or the current in the protection element  116 ) to exceed a predetermined threshold, the protection element  116  will electrically disconnect the electric conductor  112  and the electric conductor  114 , so that the primary power source no longer provides power to the primary electrical devices, which causes the primary electrical devices to stop operating. Similarly, when the primary power source fails, the primary power source no longer provides power to the primary electrical devices, which causes the primary electrical devices to stop working. As described above, when the primary electrical devices stop operating, the secondary electrical devices may be configured to replace the primary electrical devices to operate. 
     When the secondary electrical devices fail, causing the current in the electric conductor  122  or the electric conductor  124  (or the current in the protection element  126 ) to exceed a predetermined threshold, the protection element  126  will electrically disconnect the electric conductor  122  and the electric conductor  124 , so that the secondary power source no longer provides power to the secondary electrical devices, which causes the secondary electrical devices to stop operating. Similarly, when the secondary power source fails, the secondary power source no longer provides power to the secondary electrical devices, which causes the secondary electrical devices to stop working. According to an embodiment of the present application, after the secondary electrical devices stop operating, the shared electrical devices may also continue to operate, for example, the vehicle may be stopped in an emergency. Moreover, since the shared electrical devices are powered jointly by the primary power source and the secondary power source, when any one of the primary power source and the secondary power source fails, the other may continue to provide power to the shared electrical devices. 
     In some embodiments, the electrical box  100  further comprises relay(s), one or more of the power output interfaces of the electrical box  100  may be electrically connected to the relays, and the electrical devices may be electrically connected to the power output interfaces through the relays, so that the power supply to the electrical devices may be controlled by controlling the opening and closing of the relays when needed. 
     In some embodiments, at one or more edges of the base plate  101  of the electrical box  100 , it may form side plates of the electrical box  100  on which a cover plate (not shown in  FIG.  1   ) may be mounted. These side plates extend upward from a surface of the base plate  101  to form a space for accommodating various elements. Some elements, such as the power output interface  162 , may be fixed on the side plates. The base plate, the side plates and/or the cover plate may be made of any insulating material, and in some embodiments, the base plate, the side plates and/or the cover plate are made of polyamide and fiberglass, for example, made of polyamide 66 plus 30% fiberglass. The base plate, the side plates and/or the cover plate that consist of polyamide and glassfiber have good temperature resistance and are suitable for vehicle-mounted applications. 
       FIG.  2    illustrates a circuit diagram reflecting a use environment of the electrical box according to an exemplary embodiment of the present application. As shown in  FIG.  2   , the electrical box  200  comprises at least three circuits. A first circuit comprises a power input interface  213  at one end thereof and a power output interface  215  at the other end thereof, and the first circuit is configured to provide power from a first power source (i.e., a primary power source  201 ) to a first group of electrical devices  205 . A second circuit comprises a power input interface  223  at one end thereof and a power output interface  225  at the other end thereof, and the second circuit is configured to provide power from a second power source (i.e., a secondary power source  203 ) to a second group of electrical devices  207 . A third circuit is electrically connected to the first circuit and the second circuit, comprises a power output interface  262 , and is configured to provide the power from the first power source (i.e., the primary power source  201 ) and the power from the second power source (i.e., the secondary power source  203 ) to a third group of electrical devices  209 . The electrical box  200  may be, for example, the electrical box  100  in  FIG.  1   . It should be noted that, for simplicity, the ground line of the electrical box and the corresponding wire connected to the ground line are not shown in  FIG.  2   . 
     As shown in  FIG.  2   , the first circuit comprises an electric conductor  212 , a protection element  216  and an electric conductor  214 . The primary power source  201  is electrically connected to the power input interface  213  at one end of the electric conductor  212  through a protection element  202 , the electric conductor  212  is electrically connected to the electric conductor  214  through a protection element  216 , and the power output interface  215  at one end of the electric conductor  214  is electrically connected to the first group of electrical devices  205 . The first group of electrical devices may be the primary electrical devices mentioned above. The protection element  202  may be a fuse or a switch with a current detector. The power input interface  213 , the electric conductor  212 , the protection element  216 , the electric conductor  214  and the power output interface  215  may be the power input interface  113 , the electric conductor  112 , the protection element  116 , the electric conductor  114  and the power output interface  115  described above with reference to  FIG.  1   . 
     The second circuit comprises an electric conductor  222 , a protection element  226  and an electric conductor  224 . The secondary power source  203  is electrically connected to the power input interface  223  at one end of the electric conductor  222  through a protection element  204 , the electric conductor  222  is electrically connected to the electric conductor  224  through a protection element  226 , and the power output interface  225  at one end of the electric conductor  224  is electrically connected to the second group of electrical devices  207 . The second group of electrical devices may be the secondary electrical devices mentioned above. The protection element  204  may be a fuse or a switch with a current detector. The power input interface  223 , the electric conductor  222 , the protection element  226 , the electric conductor  224  and the power output interface  225  may be the power input interface  123 , the electric conductor  122 , the protection element  126 , the electric conductor  124  and the power output interface  125  described above with reference to  FIG.  1   . 
     The third circuit comprises electric conductors  232  and  234 , a safety box  268 , electric conductors  235  and  237 , and a power output interface  262 . The primary power source  201  and the secondary power source  203  are electrically connected to the electric conductors  232  and  234  through the protection elements  202  and  204  and the electric conductors  212  and  222 , respectively, then electrically connected to the power output interface  262  through the electric conductors  232  and  234 , the safety box  268  and the electric conductors  235  and  237 , and electrically connected to the third group of electrical devices  209  through the power output interface  262 . The third group of electrical devices may be the shared electrical devices mentioned above. The safety box  268  may be the safety box  168  described above with reference to  FIG.  1   , and the electric conductors  232 ,  234 ,  235  and  237  may be the electric conductors  132 ,  134 ,  135  and  137  described above with reference to  FIG.  1   . 
     As shown in  FIG.  2   , the safety box  268  comprises protection elements  281  and  282 , one end of the protection element  281  is electrically connected to the electric conductor  232 , and the other end thereof is electrically connected to an anti-reverse element  287 . One end of the protection element  282  is electrically connected to the electric conductor  234 , and the other end thereof is electrically connected to an anti-reverse element  288 . The anti-reverse element allows current to flow in one direction (e.g., a direction of the power sources toward the electrical devices) and prevents current from flowing in the opposite direction (e.g., a direction toward the power sources). One example of the anti-reverse element is a diode (i.e., an anti-reverse diode). Due to the presence of the anti-reverse element  287  and the anti-reverse element  288 , a current may be prevented from flowing from the primary power source  201  to the secondary power source  203 , and the current is prevented from flowing from the secondary power source  203  to the primary power source  201 . 
     The anti-reverse element  287  and the anti-reverse element  288  are electrically connected to the power output interface  262  through a protection element  283 , an electric conductor  251 , a protection element  285  and the electric conductor  235 . The protection elements  281 ,  282 ,  283  and  285  may be fuses or switches with current detectors. It can be seen from  FIG.  2   , the third group of electrical devices (i.e., the shared electrical devices) are powered jointly by the primary power source  201  and the secondary power source  203 . Therefore, when one of the primary power source  201  and secondary power source  203  fails, the other may continue to provide power to the third group of electrical devices. 
     As shown in  FIG.  2   , the third circuit may further comprise a voltage converter  264 , one end of the voltage converter  264  is electrically connected to the electric conductor  251  through the electric conductor  236  and the protection element  284 , the other end thereof is electrically connected to the electric conductor  237  through the electric conductor  238  and the protection element  286 , and the electric conductor  237  is electrically connected to the power output interface  262 . Thus, at least two voltages with different magnitudes may be provided on the power output interface  262 , one voltage has the same magnitude as that of one power source, and the other voltage has a larger or smaller magnitude than that of the power source. In some embodiments, the primary power source  201  and the secondary power source  203  have the same voltage. For example, the voltage of the primary power source and the secondary power source is 24 volts, and the voltage converter  264  may reduce the voltage of 24 volts to 12 volts, so that two different voltages of 24 volts and 12 volts may be provided on the power output interface  262 . 
     By providing different magnitudes of voltages on the power output interface  262 , power consumption requirements of the electrical devices with different magnitudes of voltages may be satisfied. The voltage converter  264  may be the voltage converter  164  described above with reference to  FIG.  1   . The electric conductors  236  and  238  may be the electric conductors  136  and  138  described above with reference to  FIG.  1   . 
     Each protection element in the safety box  268  may be a fuse (e.g., a slow blow fuse) or a switch with a current detector. The protection element may electrically disconnect the corresponding electric conductors when the current flowing through the corresponding electric conductors (or the current flowing through the protection element) exceeds a predetermined threshold. The predetermined threshold may be flexibly set as desired, for example, the predetermined threshold corresponding to the protection element  283  may be greater than the predetermined thresholds corresponding to the protection elements  281  and  282 . The predetermined threshold corresponding to the protection element  283  may also be greater than the predetermined thresholds corresponding to the protection elements  284 ,  285  and  286 . The predetermined thresholds corresponding to the protection element  281  and the protection element  282  may be the same. 
     In some embodiments, the electrical box  200  may also comprise more or fewer circuits. For example, the electrical box  200  may further comprise (one or more) additional circuits and/or (one or more) further additional circuits, wherein an additional circuit may have a structure that is the same as or similar to that of the first circuit, a power input interface at one end of the additional circuit is electrically connected to the primary power supply  201  through the protection element  202 , and a power output interface at the other end of the additional circuit is electrically connected to the first group of electrical devices. In a case where the additional circuit is comprised, the power output interfaces of the first circuit and the additional circuit may be electrically connected to the same or different electrical devices of the first group of electrical devices. A further additional circuit may have a structure that is the same as or similar to that of the second circuit, a power input interface at one end of the further additional circuit is electrically connected to the secondary power source  203  through the protection element  204 , and a power output interface at the other end of the further additional circuit is electrically connected to the second group of electrical devices. In a case where the further additional circuit is comprised, the power output interfaces of the second circuit and the further additional circuit may be electrically connected to the same or different electrical devices of the second group of electrical devices. 
     In  FIG.  2   , the protection element  283  is electrically connected to the power output interface  262  through a first sub-circuit comprising the electric conductor  251 , the protection element  285  and the electric conductor  235 ; and those of skilled in the art will appreciate that the electrical box  200  may further comprise more sub-circuits that are the same as or similar to the first sub-circuit, and are electrically connected between the protection element  283  and the power output interface  262 . Moreover, in  FIG.  2   , the voltage converter  264  is electrically connected to the power output interface  262  through a second sub-circuit comprising the electric conductor  238 , the protection element  286  and the electric conductor  237 ; and those of skilled in the art will appreciate that the electrical box  200  may further comprise more sub-circuits that are the same as or similar to the second sub-circuit, and are electrically connected between the voltage converter  264  and the power output interface  262 . 
       FIG.  3    is a schematic structural diagram of an electrical box according to another exemplary embodiment. The following description focuses on the differences between an electrical box  300  in  FIG.  3    and the electrical box  100  in  FIG.  1   , and the same or similar parts are not repeated. It should be noted that the same reference numerals are used for the parts of the electrical box  300  shown in  FIG.  3    that are the same as or similar to that of the electrical box  100  in  FIG.  1   . 
     As shown in  FIG.  3   , the electrical box  300  further comprises electric conductors  372 ,  374  and  376  with respect to the electrical box  100 . One end of the electric conductor  372  is electrically connected to a power input interface  382  and the other end thereof is electrically connected to the electric conductor  152  (i.e., the ground line), one end of the electric conductor  374  is electrically connected to the power input interface  382  and the other end thereof is electrically connected to a relay  386 , and the electric conductor  376  has an opening at one end and the end forms a power output interface  375 . The other end of the electric conductor  376  is electrically connected to the relay  386 . The power input interface  382 , the electric conductors  372 ,  374  and  376 , and the relay  386  may form a fourth circuit. One or more or all of the electric conductors  372 ,  374  and  376  may be composed of a metal strip and not coated with an insulating material. The cross-section of the metal strip may be rectangular, and the width of the metal strip may be at least 5 times, or at least 10 times, or at least 20 times the thickness. Because the metal strip is not coated with an insulating material, the surface of the metal strip may be subjected to anti-oxidation treatment in order to prevent the metal strip from being oxidized. For example, the metal strip may be a copper strip, and the surface of the copper strip may be tin-plated. The relay  386  has, for example, mounting holes on both sides and is fixed on the base plate  101  through the mounting holes. In some embodiments, the electric conductors  372 ,  374  and  376  have mounting holes through which the electric conductors are fixed on the base plate  101 . 
     In some embodiments, the opening in the electric conductor  376  shown in  FIG.  3    may be a round hole. In some embodiments, the electric conductor  376  may not comprise openings, instead recesses may be formed on both sides of the electric conductor  376  at locations corresponding to the openings, or protrusions (e.g., cylindrical protrusions) may be formed on the surface of the electric conductor  376 . The electric conductor  356  in  FIG.  3    (represented in the dashed line) differs from the electric conductor  156  in  FIG.  1    in that the electric conductor  356  is not directly electrically connected to the electric conductor  152  (i.e., the ground line), but is electrically connected to the electric conductor  152  (i.e., the ground line) through the electric conductor  372 . Moreover, the electric conductor  356  in  FIG.  3    is further electrically connected to the relay  386 . Also, the electrical box  300  in  FIG.  3    further comprises the electric conductor  358  (represented in the dashed line) configured to electrically connect the power input interface  382  to the electric conductor  372 . The electric conductor  358  may serve as a ground line corresponding to a signal line connected to the power input interface  382 . The electric conductors  356  and  358  may be wires (e.g., copper wires) that may be round or oval in cross-section and that have a surface coated with an insulating material. 
     In some embodiments, the primary power source and the secondary power source described above may be vehicle-mounted power sources (e.g., batteries) that may be charged by a generator of the vehicle. When the vehicle is located in a garage or parking lot, the vehicle may be powered by a power source (also called shore power) in the garage or parking lot in order to save energy on the vehicle. The power input interface  382  may be various connectors (e.g., a vehicle-scale connector), and the shore power may be electrically connected to the power input interface  382  to provide power to the electrical devices (e.g., the first group of electrical devices  205 , the second group of electrical devices  207  and/or the third group of electrical devices  209  shown in  FIG.  2   ) on the vehicle through the electric conductor  374 , the relay  386  and the electric conductor  376  (the electrical devices may be electrically connected to the power output interface  375 ). The ground line of the shore power may be electrically connected to the electric conductor  372  through the power input interface  382 . 
     As shown in  FIG.  3   , the electrical box  300  further comprises one or more signal lines  384  (represented in the dotted lines), one end of the signal line is electrically connected to the power output interface  162 , and the other end thereof is electrically connected to the relay  386 , the electric conductor  374  and the power input interface  382 . For example, a control apparatus (or controller) in the vehicle may be connected to the power output interface  162 , the control apparatus may detect the contact of the shore power with the power input interface  382  through the signal line, and the control apparatus may detect voltage or current on the electric conductor  374  through the signal line, and controls the relay  386  to open and close through the signal line according to the contact detection result and/or the voltage (or current) detection result. For example, when the control apparatus detects that the shore power is contacted with the power input interface  382  through the signal line, the control apparatus controls the relay to close so that the shore power may provide power to the electrical devices on the vehicle, and when the control apparatus detects that the voltage (or current) on the electric conductor  374  is excessive through the signal line, the control apparatus controls the relay to open. Therefore, the damage to the electrical devices resulting from the excessive voltage or current of the shore power may be avoided. 
       FIG.  4 A  is a schematic diagram of the mounting process of the cover plate of an electrical box according to an exemplary embodiment, wherein the electrical box may be, for example, the electrical box  300  shown in  FIG.  3   .  FIG.  4 B  is an enlarged view of the portion shown in block A in  FIG.  4 A . As shown in  FIG.  4 A , side plates of the electrical box, for example, side plates  402 ,  403 ,  404  and  405 , are positioned on edges of the base plate  101  and extend upward from a surface of the base plate  101  to form a space for accommodating various elements. Some elements may be fixed on the side plates, for example, the power input interface  382  is fixed on the side plate  402 . 
     The cover plate and the side plates of the electrical box may be fixed by adopting a sliding groove and a bolt, which is convenient for disassembly. As shown in  FIGS.  4 A and  4 B , the side plates  402 ,  403  and  404  have sliding grooves, the cover plate  401  has protruding sliding blocks corresponding to the sliding grooves, and the sliding blocks and the sliding grooves are in clearance fit when the sliding blocks slide in the sliding grooves, so as to mainly avoid excessive resistance of the cover plate and the side plates in the assembling process caused by processing errors and product deformation during processing. When the sliding of the sliding blocks in the sliding grooves is finished, the sliding blocks and the sliding grooves are in interference fit, so that after the cover plate is assembled, a certain retaining force is provided, and meanwhile, the assembling clearance between the cover plate and the side plates is reduced. 
     The base plate  101 , the side plates  402 ,  403 ,  404  and  405  and/or the cover plate  401  may be made of polyamide and fiberglass, for example, made of polyamide 66 plus 30% fiberglass. 
       FIG.  5    is a top view of the cover plate in  FIG.  4 A  after mounting. As shown in  FIG.  5   , when the cover plate is mounted, a portion of the power output interfaces  115 ,  125  and  375 , the power input interfaces  113  and  123 , the electric conductor  152  (i.e., the ground line) and the electric conductor  372  is exposed outside the electrical box, so as to facilitate the electrical connection of the power source, the electrical devices and the like. 
     Although exemplary embodiments or examples of the present disclosure have been described with reference to the accompanying drawings, it should be understood that the above exemplary discussion is not intended to be exhaustive or to limit the utility model to the precise forms disclosed. Many modifications and variations are possible in view of the above teachings. Therefore, the disclosed subject matter should not be limited to any single embodiment or example described herein, but rather should be construed in breadth and scope in accordance with the appended claims.