Patent Publication Number: US-2023163520-A1

Title: Liquid cooling system for a charging gun and charging gun

Description:
TECHNICAL FIELD 
     The present utility model relates to the technical field of charging guns and, in particular, to a liquid cooling system for a charging gun and a charging gun. 
     BACKGROUND 
     With the popularization of new energy electric vehicles, the development of fast charging technology becomes more and more important. A charging gun is an important component in the fast charging technology, and many mature charging gun products have emerged on the market. To improve the charging speed, shorten the charging time and improve the user experience, the charging current and the power that the charging gun use to charge a load are certainly greater and greater. 
     During the charging process of an electric vehicle, the charging current is between 500 A to 600 A, and a large amount of heat is generated at the joint between a cable and a terminal and at the joint between the cable and an external power source. This heat decreases the charging efficiency, and the excessive temperature causes a relatively large damage to the charging gun, and even causes a fire. 
     SUMMARY 
     An object of the present utility model is to provide a liquid cooling system for a charging gun and a charging gun so as to reduce the temperature at the joint between a cable and a charging terminal. 
     To achieve the above object, the present utility model provides the technical solution described below. 
     In one aspect, the present utility model provides a liquid cooling system for a charging gun. The liquid cooling system for a charging gun includes a head cooling assembly, a coolant inlet pipe, and a coolant outlet assembly. 
     The head cooling assembly includes a head housing, a first head seal assembly, a second head seal assembly, and a third head seal assembly. The head housing is provided with a terminal port and a head inlet. The terminal port and the head inlet are disposed at two ends of the head housing and communicate with the inside of the head housing. The terminal port is configured for a terminal to penetrate and to be disposed on the terminal port, the head housing is configured to accommodate a connection end of the terminal, and the head inlet is configured to enable a cable to extend into the head housing to connect to the connection end of the terminal. The first head seal assembly is disposed in the head housing and sealingly disposed at a joint between the connection end of the terminal and the cable, the second head seal assembly is sealingly disposed at the terminal port, and the third head seal assembly is sealingly disposed at the head inlet. 
     An outlet end of the coolant inlet pipe extends from the head inlet into the head housing. 
     An inlet end of the coolant outlet assembly extends from the head inlet into the head housing and communicates with the outlet end of the coolant inlet pipe. 
     As a preferred embodiment of the liquid cooling system for a charging gun, the first head seal assembly includes a head enclosing member, a head connection member, and a first head seal ring. The head enclosing member is configured to wrap the joint between the connection end of the terminal and the cable. One end of the head connection member is connected to the end of the head enclosing member away from the terminal, and the first head seal ring is disposed between the head connection member and the cable and disposed at the end of the head enclosing member away from the terminal. The head enclosing member, the head connection member, and the first head seal ring form a head seal chamber surrounding the outer side of the cable. 
     In a preferred embodiment of the liquid cooling system for a charging gun, the second head seal assembly includes a second head seal ring. The periphery of the end of the head enclosing member away from the cable is provided with an annular groove. The annular groove and an inner sidewall of the terminal port enclose to form an annular seal chamber, and the second head seal ring is disposed in the annular seal chamber. 
     In a preferred embodiment of the liquid cooling system for a charging gun, the coolant inlet pipe is configured to enable the cable to penetrate the coolant inlet pipe and enable the cable to extend into the first head seal assembly to connect to the connection end of the terminal. The end of the head connection member away from the head enclosing member is connected to the outlet end of the coolant inlet pipe, and the outlet end of the coolant inlet pipe extends from the head inlet, through the third head seal assembly and into the head connection member. 
     In a preferred embodiment of the liquid cooling system for a charging gun, the head connection member includes a liquid outlet hole. The liquid outlet hole is disposed between the outlet end of the coolant inlet pipe and the first head seal ring, and the head seal chamber communicates with the inside of the head housing through the liquid outlet hole. 
     In a preferred embodiment of the liquid cooling system for a charging gun, the head connection member is a tubular structure, the head connection member comprises a plurality of liquid outlet holes, and the plurality of liquid outlet holes are annularly disposed at the head connection member. 
     In a preferred embodiment of the liquid cooling system for a charging gun, the head enclosing member includes a first threaded portion, and the head connection member includes a second threaded portion, a first neck portion, and a first stopper portion. The first threaded portion is connected to the second threaded portion. The first neck portion is disposed between the second threaded portion and the first stopper portion. The first head seal ring is sandwiched between the first stopper portion and the head enclosing member. An outer peripheral surface of the first head seal ring is configured to contact the first neck portion, and an inner peripheral surface of the first head seal ring is configured to contact the cable. 
     In a preferred embodiment of the liquid cooling system for a charging gun, the coolant outlet assembly includes a coolant outlet pipe and a water outlet pipe, and the third head seal assembly includes a head support plate, a head waterproof member, and a head cover. The head support plate is fixed in the head housing, the head cover is disposed at the head inlet, and the head waterproof member is sandwiched between the head cover and the head support plate. The head support plate is provided with a support inlet port and a support outlet port. The head waterproof member is provided with a waterproof inlet port and a waterproof outlet port. The head cover is provided with a head cover inlet port and an avoidance port. The outlet end of the coolant inlet pipe sequentially passes through the head cover inlet port, the waterproof inlet port, and the support inlet port. One end of the water outlet pipe communicates with the outlet end of the coolant inlet pipe, and another end of the water outlet pipe sequentially passes through the support outlet port, the waterproof outlet port and the avoidance port and then is connected to the coolant outlet pipe. 
     In a preferred embodiment of the liquid cooling system for a charging gun, the third head seal assembly further includes a ballast plate. The ballast plate is provided with a plate inlet port and a plate outlet port, and the ballast plate is disposed between the head cover and the head waterproof member. The coolant inlet pipe passes through the plate inlet port, and the water outlet pipe passes through the plate outlet port. 
     In a preferred embodiment of the liquid cooling system for a charging gun, a tail cooling assembly is further included. The tail cooling assembly includes a tail housing, a first tail seal assembly, a second tail seal assembly, and a third tail seal assembly. The tail housing is provided with a tail inlet, a tail outlet, and a liquid inlet. An inlet end of the coolant inlet pipe passes through the tail outlet and disposed in the tail housing. The tail inlet is configured for an external connection member to pass through and part of the external connection member is disposed in the tail housing. The tail housing is configured to accommodate another end of the cable away from the head cooling assembly and enable the cable to connect to the external connection member. The first tail seal assembly is sealingly disposed at a joint between the cable and the external connection member. The second tail seal assembly is sealingly disposed at the tail outlet. The third tail seal assembly is sealingly disposed at the tail inlet. The liquid inlet is configured to allow a coolant to enter the tail housing. 
     In a preferred embodiment of the liquid cooling system for a charging gun, the first tail seal assembly includes a tail enclosing member, a tail connection member, and a first tail seal ring. The tail enclosing member is configured to wrap the joint between the cable and the external connection member. One end of the tail connection member is connected to the end of the tail enclosing member away from the external connection member. The first tail seal ring is disposed between the tail connection member and the cable and disposed at the end of the tail enclosing member away from the external connection member. The tail enclosing member, the tail connection member, and the first tail seal ring form a tail seal chamber surrounding the outer side of the cable. 
     In a preferred embodiment of the liquid cooling system for a charging gun, the coolant inlet pipe is configured to enable the cable to penetrate the coolant inlet pipe and to enable the cable to extend into the first tail seal assembly to connect to the external connection member. The end of the tail connection member away from the tail enclosing member is connected to the inlet end of the coolant inlet pipe, and the inlet end of the coolant inlet pipe extends from the tail outlet, through the second tail seal assembly and into the tail connection member. 
     In a preferred embodiment of the liquid cooling system for a charging gun, the tail connection member includes a liquid inlet hole. The liquid inlet hole is disposed between the inlet end of the coolant inlet pipe and the first tail seal ring, and the tail seal chamber communicates with the inside of the tail housing through the liquid inlet hole. 
     In a preferred embodiment of the liquid cooling system for a charging gun, the tail connection member is a tubular structure, the tail connection member comprises a plurality of liquid inlet holes, and the plurality of liquid inlet holes are annularly disposed in the tail connection member. 
     In a preferred embodiment of the liquid cooling system for a charging gun, the tail enclosing member includes a third threaded portion, and the tail connection member includes a fourth threaded portion, a second neck portion, and a second stopper portion. The third threaded portion is connected to the fourth threaded portion. The second neck portion is disposed between the fourth threaded portion and the second stopper portion. The first tail seal ring is sandwiched between the second stopper portion and the tail enclosing member. An outer peripheral surface of the first tail seal ring is configured to contact the second neck portion, and an inner peripheral surface of the first tail seal ring is configured to contact the cable. 
     In a preferred embodiment of the liquid cooling system for a charging gun, the second tail seal assembly includes a first tail support plate, a first tail waterproof member, and a first tail cover. The first tail support plate is fixed in the tail housing. The first tail cover is disposed at the tail outlet. The first tail waterproof member is sandwiched between the first tail support plate and the first tail cover. The first tail support plate is provided with a support outlet, the first tail waterproof member is provided with a waterproof outlet, and the first tail cover is provided with a tail cover outlet. The coolant inlet pipe sequentially passes through the support outlet, the waterproof outlet and the tail cover outlet from inside to outside. 
     In a preferred embodiment of the liquid cooling system for a charging gun, the third tail seal assembly includes a second tail support plate, a second tail waterproof member, and a second tail cover. The second tail support plate is fixed in the tail housing. The second tail cover is disposed at the tail inlet. The second tail waterproof member is sandwiched between the second tail support plate and the second tail cover. The second tail support plate is provided with a support inlet, the second tail waterproof member is provided with a waterproof inlet, and the second tail cover is provided with a tail cover inlet. The tail enclosing member sequentially passes through the support inlet, the waterproof inlet and the tail cover inlet from inside to outside. 
     In another aspect, the present utility model provides a charging gun including the liquid cooling system for a charging gun, the terminal and the cable in any one of the above solutions. The terminal penetrates the terminal port, the connection end of the terminal is accommodated in the head housing, the cable extends through the head inlet into the head housing, and the first head seal assembly is sealingly disposed at the joint between the connection end of the terminal and the cable. 
     The present utility model has beneficial effects described below. 
     The present utility model provides a liquid cooling system for a charging gun. The liquid cooling system for a charging gun includes a head cooling assembly, a coolant inlet pipe, and a coolant outlet assembly. The head cooling assembly includes a head housing, a first head seal assembly, a second head seal assembly, and a third head seal assembly. The head housing is provided with a terminal port and a head inlet. The terminal port and the head inlet are disposed at two ends of the head housing and communicate with the inside of the head housing. The terminal port is configured for a terminal to penetrate and to be disposed on the terminal port, the head housing is configured to accommodate a connection end of the terminal, and the head inlet is configured to enable a cable to extend into the head housing and connect to the connection end of the terminal. The first head seal assembly is disposed in the head housing and sealingly disposed at a joint between the connection end of the terminal and the cable, the second head seal assembly is sealingly disposed at the terminal port, and the third head seal assembly is sealingly disposed at the head inlet. An outlet end of the coolant inlet pipe extends from the head inlet into the head housing. An inlet end of the coolant outlet assembly extends from the head inlet into the head housing and communicates with the outlet end of the coolant inlet pipe. In the present utility model, the above arrangement enables the inflow and outflow of the coolant in the head housing to continuously carry away the heat generated at the joint between the cable and the terminal, thereby reducing the temperature at the joint between the cable and the terminal, improving the charging efficiency, and reducing a risk in charging. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a view illustrating the structure of a charging gun according to an embodiment of the present utility model; 
         FIG.  2    is a view illustrating the structure of a liquid cooling system for a charging gun according to an embodiment of the present utility model; 
         FIG.  3    is a view illustrating the structure of a head cooling assembly according to an embodiment of the present utility model; 
         FIG.  4    is a sectional view illustrating the structure of a head enclosing member, a first head seal ring and a head connection member according to an embodiment of the present utility model; 
         FIG.  5    is a view illustrating the structure of a head housing according to embodiments of the present utility model; 
         FIG.  6    is a view illustrating the structure of a tail cooling assembly according to embodiments of the present utility model; 
         FIG.  7    is a sectional view illustrating the structure of a tail enclosing member, a first tail seal ring, and a tail connection member according to embodiments of the present utility model; and 
         FIG.  8    is a view illustrating the structure of a tail housing according to embodiments of the present utility model. 
     
    
    
     REFERENCE LIST 
     
         
         
           
               100  cable 
               200  coolant inlet pipe 
               300  coolant outlet assembly 
               301  coolant outlet pipe 
               302  water outlet pipe 
               400  three-way pipe 
               1  head cooling assembly 
               11  head housing 
               111  terminal port 
               112  head inlet 
               113  flow guiding member 
               12  first head seal assembly 
               121  head enclosing member 
               1211  first threaded portion 
               122  head connection member 
               1221  liquid outlet hole 
               1222  second threaded portion 
               1223  first neck portion 
               1224  first stopper portion 
               123  first head seal ring 
               13  second head seal assembly 
               14  third head seal assembly 
               141  head support plate 
               142  head waterproof member 
               143  head cover 
               144  ballast plate 
               15  terminal 
               2  tail cooling assembly 
               21  tail housing 
               211  tail inlet 
               212  tail outlet 
               213  liquid inlet 
               214  raised strip 
               22  first tail seal assembly 
               221  tail enclosing member 
               2211  third threaded portion 
               222  tail connection member 
               2221  liquid inlet hole 
               2222  fourth threaded portion 
               2223  second neck 
               2224  second stopper portion 
               223  first tail seal ring 
               23  second tail seal assembly 
               231  first tail support plate 
               232  first tail waterproof member 
               233  first tail cover 
               234  first sealant 
               24  third tail seal assembly 
               241  second tail support plate 
               242  second tail waterproof member 
               243  second tail cover 
               244  second sealant 
               25  external connection member 
           
         
       
    
     DETAILED DESCRIPTION 
     Technical solutions of the present utility model are clearly and completely described below in conjunction with the drawings. Apparently, embodiments described herein are part, not all, of the embodiments of the present utility model. Based on the embodiments of the present utility mode, all other embodiments obtained by those of ordinary skill in the art are within the scope of the present utility mode on the premise that no creative work is done. 
     In the description of the present utility model, it should be noted that the orientations or position relations indicated by terms such as “center”, “above”, “below”, “left”, “right”, “vertical”, “horizontal”, “inside”, “outside”, and the like are based on orientations or position relations shown in the drawings. These orientations or position relations are intended only to facilitate and simplify description of the present utility model and not to indicate or imply that a device or element referred to must have such specific orientations or must be configured or operated in such specific orientations. Thus, these orientations or position relations are not to be construed as limiting the present utility model. Moreover, terms such as “first” and “second” are used merely for the purpose of description and are not to be construed as indicating or implying relative importance. Terms “first position” and “second position” are two different positions. Moreover, when the first feature is described as “on”, “above”, or “over” the second feature, the first feature is right on, above, or over the second feature or the first feature is obliquely on, above, or over the second feature, or the first feature is simply at a higher level than the second feature. When the first feature is described as “under”, “below” or “underneath” the second feature, the first feature is right under, below or underneath the second feature or the first feature is obliquely under, below or underneath the second feature, or the first feature is simply at a lower level than the second feature. 
     In the description of the present utility model, it is to be noted that, unless otherwise expressly specified and limited, the term “mounting”, “connected to each other”, or “connected” is to be construed in a broad sense, for example, as securely connected, detachably connected, or integrally connected; mechanically connected or electrically connected; directly connected to each other or indirectly connected to each other via an intermediary; or internally connected between two elements. For those of ordinary skill in the art, specific meanings of the preceding terms in the present utility model may be understood based on specific situations. 
     The embodiments of the present utility model are described below in detail. Examples of the embodiments are shown in the drawings. The same or similar reference numerals indicate the same or similar elements or components having the same or similar functions. The embodiments described below with reference to the drawings are exemplary, merely used to explain the present utility model, and not to be construed as limiting the present utility model. 
     Embodiment One 
     As shown in  FIGS.  2 ,  3  and  6   , this embodiment provides a liquid cooling system for a charging gun. The liquid cooling system for a charging gun includes a head cooling assembly  1 , a coolant inlet pipe  200 , and a coolant outlet assembly  300 . The head cooling assembly  1  includes a head housing  11 , a first head seal assembly  12 , a second head seal assembly  13 , and a third head seal assembly  14 . The head housing  11  is provided with a terminal port  111  and a head inlet  112 . The terminal port  111  and the head inlet  112  are disposed at two ends of the head housing  11  and communicate with the inside of the head housing  11 . The terminal port  111  is configured for a terminal  15  to penetrate and to be disposed on the terminal port  111 , the head housing  11  is configured to accommodate a connection end of the terminal  15 , and the head inlet  112  is configured to enable a cable  100  to extend into the head housing  11  to connect to the connection end of the terminal  15 . The first head seal assembly  12  is disposed in the head housing  11  and sealingly disposed at a joint between the connection end of the terminal  15  and the cable  100 , the second head seal assembly  13  is sealingly disposed at the terminal port  111 , and the third head seal assembly  14  is sealingly disposed at the head inlet  112 . An outlet end of the coolant inlet pipe  200  extends from the head inlet  112  into the head housing  11 . An inlet end of the coolant outlet assembly  300  extends from the head inlet  112  into the head housing  11  and communicates with the outlet end of the coolant inlet pipe  200 . 
     Optionally, in this embodiment, two terminals  15  are provided for the positive output of a current and the negative output of the current, respectively. In some embodiments, the liquid cooling system of the charging gun is suitable for a direct-current charging gun, and the terminal  15  is a DC terminal, that is, a terminal for transmitting a DC current, where DC is an abbreviation of direct current. 
     In this embodiment, the arrangement of the above structure allows the coolant to continuously flow into the head housing  11  through the coolant inlet pipe  200  and flow out through the coolant outlet assembly  300 . The coolant circulates through the head housing  11  to carry away the heat generated at the joint between the cable  100  and the terminal  15 , thereby reducing the temperature at the joint between the cable  100  and the terminal  15 , improving the charging efficiency, and reducing a risk in charging. 
     Preferably, the first head seal assembly  12  includes a head enclosing member  121 , a head connection member  122 , and a first head seal ring  123 . The head enclosing member  121  is configured to wrap the joint between the connection end of the terminal  15  and the cable  100 . One end of the head connection member  122  is connected to the end of the head enclosing member  121  away from the terminal  15 , and the first head seal ring  123  is disposed between the head connection member  122  and the cable  100  and disposed at the end of the head enclosing member  121  away from the terminal  15 . The head enclosing member  121 , the head connection member  122 , and the first head seal ring  123  form a head seal chamber surrounding the outer side of the cable  100 . With the arrangement of the above structure, the coolant does not enter the joint between the connection end of the terminal  15  and the cable  100  along the gap between the head enclosing member  121  and the cable  100 , thereby ensuring the sealing effect between the connection end of the terminal  15  and the cable  100 . In some embodiment, the head enclosing member is an over-molding member. In some embodiment, the head enclosing member is over-molded by plastic. 
     With respect to the structure of the second head seal assembly  13  in this embodiment, optionally, the second head seal assembly  13  includes a second head seal ring. The periphery of the end of the head enclosing member  121  away from the cable  100  is provided with an annular groove. The annular groove and the inner sidewall of the terminal port  111  enclose to form an annular seal chamber, and the second head seal ring is disposed in the annular seal chamber. This arrangement can prevent the coolant from flowing out of the head housing  11 . In addition, another end of the head enclosing member  121  is disposed at the side of the second head seal ring away from the internal chamber of the head housing  11 , so that the coolant is prevented from entering the joint between the connection end of the terminal  15  and the cable  100  along the gap between the another end of the head enclosing member  121  and the cable  100 . 
     With reference to  FIG.  3    and  FIG.  4   , preferably, the cable  100  penetrate the coolant inlet pipe  200 . This arrangement can cool down the entire cable  100 , further reducing a risk in charging. In addition, the above arrangement also avoids providing a separate sealing member between the cable  100  and the head housing  11 , thereby further reducing the cost. 
     Specifically, the coolant inlet pipe  200  is configured to enable the cable  100  to penetrate the coolant inlet pipe  200  and enable the cable  100  to extend into the first head seal assembly  12  to connect to the connection end of the terminal  15 . The end of the head connection member  122  away from the head enclosing member  121  is connected to the outlet end of the coolant inlet pipe  200 , and the outlet end of the coolant inlet pipe  200  extends from the head inlet  112 , through the third head seal assembly  14  and into the head connection member  122 . This arrangement enables the heat of the cable  100  to be carried away as the coolant flows, thereby lowering the temperature of the entire cable  100 . In addition, the above arrangement ensures that the coolant inlet pipe  200  and the head connection member  122  are relatively fixed, thereby ensuring that the coolant inlet pipe  200  and the terminal  15  are relatively fixed, so that the position of the cable  100  in the coolant inlet pipe  200  is relatively fixed and in a relatively central position, thereby ensuring that the coolant can flow out of the coolant inlet pipe  200  uniformly. 
     Preferably, the head connection member  122  includes a liquid outlet hole  1221 . The liquid outlet hole  1221  is disposed between the outlet end of the coolant inlet pipe  200  and the first head seal ring  123 , and the head seal chamber communicates with the head housing  11  through the liquid outlet hole  1221 . The arrangement of the above structure enables the coolant to enter the head housing  11  from the coolant inlet pipe  200  so as to cool the terminal  15  disposed in the head housing  11 . 
     Further, the head connection member  122  is a tubular structure, the head connection member  122  includes a plurality of liquid outlet holes  1221 , and the plurality of liquid outlet holes  1221  are annularly disposed in the head connection member  122 . The plurality of liquid outlet holes  1221  are provided so that the outflow of the coolant is relatively smooth, and the flow of the coolant is prevented from being affected after one of the liquid outlet holes  1221  is blocked. Since the outlet end of the coolant inlet pipe  200  communicates with the head seal chamber, the structure in which the plurality of liquid outlet holes  1221  are annularly disposed in the head connection member  122  allows the coolant to flow out more uniformly, and thus the terminal  15  disposed in the head housing  11  can be fully cooled. 
     Specifically, the head enclosing member  121  includes a first threaded portion  1211 , and the head connection member  122  includes a second threaded portion  1222 , a first neck portion  1223 , and a first stopper portion  1224 . The first threaded portion  1211  is connected to the second threaded portion  1222 . The first neck portion  1223  is disposed between the second threaded portion  1222  and the first stopper portion  1224 . The first head seal ring  123  is sandwiched between the first stopper portion  1224  and the head enclosing member  121 . The outer peripheral surface of the first head seal ring  123  is configured to contact the first neck portion  1223 , and the inner peripheral surface of the first head seal ring  123  is configured to contact the cable  100 . The arrangement of the above structure can achieve the connection between the head connection member  122  and the head enclosing member  121  and the fixing of the first head seal ring  123 . In other implementations of this embodiment, the connection between the head connection member  122  and the head enclosing member  121  may also be clamping. 
     With reference to  FIG.  6    and  FIG.  7   , preferably, the coolant outlet assembly  300  includes a coolant outlet pipe  301  and a water outlet pipe  302 , and the third head seal assembly  14  includes a head support plate  141 , a head waterproof member  142 , and a head cover  143 . The head support plate  141  is fixed in the head housing  11 , the head cover  143  is disposed at the head inlet  112 , and the head waterproof member  142  is sandwiched between the head cover  143  and the head support plate  141 . The head support plate  141  is provided with a support inlet port and a support outlet port. The head waterproof member  142  is provided with a waterproof inlet port and a waterproof outlet port. The head cover  143  is provided with a head cover inlet port and an avoidance port. The outlet end of the coolant inlet pipe  200  sequentially passes through the head cover inlet port, the waterproof inlet port and the support inlet port. One end of the water outlet pipe  302  communicates with the outlet end of the coolant inlet pipe  200 , and another end of the water outlet pipe  302  sequentially passes through the support outlet port, the waterproof outlet port and the avoidance port and then is connected to the coolant outlet pipe  301 . With the arrangement of the above structure, the head inlet  112  can be sealed. Optionally, the water outlet pipe  302  and the head support plate  141  are sealingly connected or integrally formed. Preferably, a flow guiding member  113  is disposed in the head housing  11 . The flow guiding member  113  is disposed between the inlet of the water outlet pipe  302  and the outlet end of the coolant inlet pipe  200  and extends along the direction of the outlet end of the coolant inlet pipe  200 . Further, in this embodiment, two flow guiding members  113  are provided. The arrangement of the two flow guiding members  113  makes the communication chamber between the inlet end of the coolant outlet assembly  300  and the outlet end of the coolant inlet pipe  200  narrow, so that the coolant needs to enter the water outlet pipe  302  through a relatively narrow chamber after flowing out from the outlet end of the coolant inlet pipe  200 . Therefore, the flow distance of the coolant in the head housing  11  is further enlarged, and the coolant flow directly from the outlet end of the coolant inlet pipe  200  to the water outlet pipe  302  is prevented, thereby improving the cooling effect. 
     In this embodiment, with respect to the structure of the flow guiding member  113 , specifically, the flow guiding member  113  may include a flow guiding bar. The flow guiding bar is disposed on the inner wall of the head housing  11  and disposed parallel to the extending direction of the terminal  15 . This arrangement, on the one hand, can narrow the communication chamber between the inlet end of the coolant outlet assembly  300  and the outlet end of the coolant inlet pipe  200 , thereby increasing the flow path of the coolant. On the other hand, the head housing  11  can also be reinforced, increasing the strength of the head housing  11 . 
     In this embodiment, optionally, the plurality of liquid outlet holes  1221  are disposed obliquely, and the center line of the liquid outlet hole  1221  is oblique from the inside of the head connection member  122  to the outside of the head connection member  122  and toward the joint between the connection end of the terminal  15  and the cable  100 . The inclined liquid outlet hole  1221  is provided so that the coolant can move toward the joint between the connection end of the terminal  15  and the cable  100  after the coolant is ejected from the liquid outlet hole  1221 , thereby more effectively cooling the joint between the connection end of the terminal  15  and the cable  100 . In this embodiment, since the inlet end of the coolant outlet assembly  300  extends into the head housing  11  from the head inlet  112 , so that the flow path of the coolant is further increased, and the cooling capacity of the coolant at the same flow rate is improved. 
     With reference to  FIG.  3   , in this embodiment, preferably, the head support plate  141  abuts against the end of the head connection member  122  facing the coolant inlet pipe  200 , the inner sidewall of the terminal port  111  is provided with a raised strip, and the end of the head enclosing member  121  away from the coolant inlet pipe  200  abuts against the raised strip. This arrangement allows the head connection member  122  and the head enclosing member  121  to be relatively fixed, thereby ensuring the head support plate  141  to be relatively fixed with respect to the head housing  11 . Moreover, this arrangement allows the space of the internal chamber of the head housing  11  to be as large as possible, increases the amount of coolant that can be accommodated, and improves the speed of heat transfer. 
     Preferably, the third head seal assembly  14  further includes a ballast plate  144 . The ballast plate  144  is provided with a plate inlet port and a plate outlet port. Moreover, the ballast plate  144  is disposed between the head cover  143  and the head waterproof member  142 . The coolant inlet pipe  200  passes through the plate inlet port, and the water outlet pipe  302  passes through the plate outlet port. In this embodiment, optionally, the head waterproof member  142  may be a silicone pad. In this embodiment, this arrangement enables the ballast plate  144  to compress the head waterproof member  142  and also prevent radial deformation of the head waterproof member  142 . In addition, the head cover  143  only needs to complete the connection with the head housing  11  and the function of pressing against the ballast plate  144 , thereby reducing the processing difficulty of the head cover  143  and further reducing the production cost. 
     With reference to  FIGS.  6  to  8   , in this embodiment, preferably, the liquid cooling system for a charging gun further includes a tail cooling assembly  2 . The tail cooling assembly  2  includes a tail housing  21 , a first tail seal assembly  22 , a second tail seal assembly  23 , and a third tail seal assembly  24 . The tail housing  21  is provided with a tail inlet  211 , a tail outlet  212 , and a liquid inlet  213 . An inlet end of the coolant inlet pipe  200  passes through the tail outlet  212  into the tail housing  21 . The tail inlet  211  is configured for an external connection member  25  to pass through such that part of the external connection member  25  is disposed in the tail housing  21 . The tail housing  21  is configured to accommodate another end of the cable  100  away from the head cooling assembly  1  and to enable the cable  100  to connect to the external connection member  25 . The first tail seal assembly  22  is sealingly disposed at a joint between the cable  100  and the external connection member  25 . The second tail seal assembly  23  is sealingly disposed at the tail outlet  212 . The third tail seal assembly  24  is sealingly disposed at the tail inlet  211 . The liquid inlet  213  is configured to allow a coolant to enter the tail housing  21 . With the arrangement of the tail cooling assembly  2 , the heat generated at the joint between the cable  100  and the external connection member  25  is carried away by the coolant, thereby lowering the temperature at the joint and reducing a risk in charging. 
     Further, the connection end between the cable  100  and the external connection member  25  is provided with a copper sheet, the external connection member  25  is a copper busbar, and ultrasonic welding is preferably performed between the copper sheet and the copper busbar. In other implementations of this embodiment, the cable  100  may be distributed and welded on the copper busbar. 
     Optionally, two tail cooling assemblies are provided for cooling the joint between the positive cable  100  and the external connection member  25  and the joint between the negative cable  100  and the external connection member  25 , respectively. Moreover, liquid inlets  213  of the two tail cooling assemblies are merged into a main pipe through a sub-pipe and a three-way pipe  400 . This arrangement reduces the pipe arrangement, saves the cost, and facilitates the transfer of the charging gun. 
     With respect to the first tail seal assembly  22 , in this embodiment, optionally, the first tail seal assembly  22  includes a tail enclosing member  221 , a tail connection member  222 , and a first tail seal ring  223 . The tail enclosing member  221  is configured to wrap the joint between the cable  100  and the external connection member  25 . One end of the tail connection member  222  is connected to the end of the tail enclosing member  221  away from the external connection member  25 . The first tail seal ring  223  is disposed between the tail connection member  222  and the cable  100  and disposed at the end of the tail enclosing member  221  away from the external connection member  25 . The tail enclosing member  221 , the tail connection member  222 , and the first tail seal ring  223  form a tail seal chamber surrounding the outer side of the cable  100 . With the above arrangement, the coolant can be prevented from entering the joint between the cable  100  and the external connection member  25  from the gap between the tail enclosing member  221  and the cable  100 , thereby playing a waterproof role. In some embodiment, the tail enclosing member is an over-molding member. In some embodiment, the tail enclosing member is over-molded by plastic. 
     Optionally, the coolant inlet pipe  200  is configured to enable the cable  100  to penetrate the coolant inlet pipe  200  and enable the cable  100  to extend into the first tail seal assembly  22  to connect to the external connection member  25 . The end of the tail connection member  222  away from the tail enclosing member  221  is connected to the inlet end of the coolant inlet pipe  200 , and the inlet end of the coolant inlet pipe  200  extends from the tail outlet  212 , through the second tail seal assembly  23  and into the tail connection member  222 . This arrangement allows the heat of the cable  100  to be carried away as the coolant flows, thereby lowering the temperature of the entire cable  100 . In addition, the above arrangement ensures that the coolant inlet pipe  200  and the tail connection member  222  are relatively fixed, thereby ensuring that the coolant inlet pipe  200  and the external connection member  25  are relatively fixed, so that the position of the cable  100  in the coolant inlet pipe  200  is relatively fixed and in a relatively central position, thereby ensuring that the coolant can flow into the coolant inlet pipe  200  uniformly. In the second aspect, the cable  100  is more reliably connected to the external connection member  25 . 
     Optionally, the tail connection member  222  includes a liquid inlet hole  2221 . The liquid inlet hole  2221  is disposed between the inlet end of the coolant inlet pipe  200  and the first tail seal ring  223 , and the tail seal chamber communicates with the inside of the tail housing  21  through the liquid inlet hole  2221 . The arrangement of the above structure enables the coolant to enter the coolant inlet pipe  200  from the head housing  11  so as to flow into the head housing  11 . 
     Further, the tail connection member  222  is a tubular structure, the tail connection member  222  includes a plurality of liquid inlet holes  2221 , and the plurality of liquid inlet holes  2221  are annularly disposed in the tail connection member  222 . The plurality of liquid inlet holes  2221  are provided so that the inflow of the coolant is relatively smooth, and the flow of the coolant is prevented from being affected after one of the liquid inlet holes  2221  is blocked. Since the tail seal chamber communicates with the inlet end of the coolant inlet pipe  200 , the structure in which the plurality of liquid inlet holes  2221  are annularly disposed in the tail connection member  222  allows the coolant to flow in more uniformly, and thus the cable  100  disposed in the coolant inlet pipe  200  can be fully cooled. 
     Specifically, the tail enclosing member  221  includes a third threaded portion  2211 , and the tail connection member  222  includes a fourth threaded portion  2222 , a second neck portion  2223 , and a second stopper portion  2224 . The third threaded portion  2211  is connected to the fourth threaded portion  2222 . The second neck portion  2223  is disposed between the fourth threaded portion  2222  and the second stopper portion  2224 . The first tail seal ring  223  is sandwiched between the second stopper portion  2224  and the tail enclosing member  221 . An outer peripheral surface of the first tail seal ring  223  is configured to contact the second neck portion  2223 , and an inner peripheral surface of the first tail seal ring  223  is configured to contact the cable  100 . The arrangement of the above structure enables the connection between the tail connection member  222  and the tail enclosing member  221  and the fixing of the first tail seal ring  223 . Optionally, in other implementations of this embodiment, the connection between the tail connection member  222  and the tail enclosing member  221  is clamping. 
     Preferably, the second tail seal assembly  23  includes a first tail support plate  231 , a first tail waterproof member  232 , and a first tail cover  233 . The first tail support plate  231  is fixed in the tail housing  21 . The first tail cover  233  is disposed at the tail outlet  212 . The first tail waterproof member  232  is sandwiched between the first tail support plate  231  and the first tail cover  233 . The first tail support plate  231  is provided with a support outlet, the first tail waterproof member  232  is provided with a waterproof outlet, and the first tail cover  233  is provided with a tail cover outlet. The coolant inlet pipe  200  sequentially passes through the support outlet, the waterproof outlet and the tail cover outlet from inside to outside. With the above arrangement, sealing of the tail outlet  212  is achieved. Optionally, a first sealant  234  is poured at the tail outlet  212  to seal the gap between the first tail cover  233  and the tail outlet  212  and the gap between the first tail cover  233  and the coolant inlet pipe  200 . 
     In this embodiment, preferably, the third tail seal assembly  24  includes a second tail support plate  241 , a second tail waterproof member  242 , and a second tail cover  243 . The second tail support plate  241  is fixed in the tail housing  21 . The second tail cover  243  is disposed at the tail inlet  211 . The second tail waterproof member  242  is sandwiched between the second tail support plate  241  and the second tail cover  243 . The second tail support plate  241  is provided with a support inlet, the second tail waterproof member  242  is provided with a waterproof inlet, and the second tail cover  243  is provided with a tail cover inlet. The tail enclosing member  221  sequentially passes through the support inlet, the waterproof inlet and the tail cover inlet from inside to outside. With the above arrangement, sealing of the tail inlet  211  is achieved. Optionally, a second sealant  244  is poured at the tail inlet  211  to seal the gap between the second tail cover  243  and the tail inlet  211 , the gap between the second tail cover  243  and the tail enclosing member  221 , and the gap between the tail enclosing member  221  and the external connection member  25 . 
     Optionally, the inner wall of the tail housing  21  is provided with two raised strips  214  opposite to each other, and two ends of each of the two raised strips  214  abut against and support the first tail support plate  231  and the second tail support plate  241  respectively. This arrangement allows the volume of the internal chamber of the tail housing  21  to be as large as possible, increases the amount of coolant that can be accommodated, and improves the speed of heat transfer. 
     In this embodiment, preferably, each of the head cooling assembly  1  and the tail cooling assembly  2  includes a liquid leakage detector, and the liquid leakage detector is configured to detect whether a liquid is leaking from the head housing  11  and the tail housing  21 . 
     Embodiment Two 
     With reference to  FIGS.  1  to  3   , this embodiment further provides a charging gun including the liquid cooling system for a charging gun, the terminal  15  and the cable  100  in the above solution. The terminal  15  penetrates the terminal port  111 , the connection end of the terminal  15  is accommodated in the head housing  11 , the cable  100  extends through the head inlet  112  into the head housing  11 , and the first head seal assembly  12  is sealingly disposed at the joint between the connection end of the terminal  15  and the cable  100 . 
     Apparently, the preceding embodiments of the present utility model are merely example embodiments for clearly illustrating the present utility model and are not intended to limit the implementations of the present utility model. For those of ordinary skill in the art, changes or alterations in other different forms may also be made based on the preceding description. Implementations of the present disclosure cannot be and do not need to be all exhausted herein. Any modification, equivalent, improvement and the like made within the spirit and principle of the present utility model shall be within the scope of the claims of the present utility model.