Power tool, lighting device, battery pack and charger

Abstract

The invention discloses a power tool, a lighting device, a battery pack and a charger. The power tool comprises a circuit board assembly which is at least partially arranged in a shell; the circuit board assembly is connected with the motor to control the motor; the circuit board assembly comprises at least one heating part, and the heating part generates temperature rise when the power tool runs; the active heat dissipation assembly is configured to guide fluid flow by using vibration motion; the fluid faces a surface of the at least one heat generating portion to extract heat from the at least one heat generating portion.

Description

Technical Field

[0001] The present application relates to the field of electric tools, and in particular to a power tool, a lighting device, a battery pack and a charger. Background Art

[0002] In the related art, whether it is the power tool itself (including DC power tools, AC power tools and pneumatic tools), the battery pack for charging the DC tool and the charger for charging the battery pack, in order to achieve better control effect, a control unit with electronic components is set. In order to ensure the reliable application of electronic components, an over-temperature protection point is set, and when the temperature reaches the over-temperature protection point, the protection program is started.

[0003] Especially for battery packs, which also have battery cells, to ensure safe use, the thermal management of the battery cells in the battery pack also needs to set an over-temperature protection point. When the temperature reaches the over-temperature protection point, the protection program is started.

[0004] Generally speaking, after the protection program is started, the output power and output power of the product will be affected. If the heat dissipation is not good and the protection program is frequently entered, it will inevitably affect the application of the product.

[0005] This section provides background information related to the present application which is not necessarily prior art. Summary of the invention

[0006] One object of the present application is to solve or at least alleviate part or all of the above problems. To this end, one object of the present application is to provide a power tool, a lighting device, a battery pack and a charger.

[0007] In order to achieve the above objectives, this application adopts the following technical solutions: A power tool comprises: a housing; an output portion configured to output power; a motor, at least partially disposed in the housing; a motor driving the output portion; a power supply, at least supplying power to the motor; a circuit board assembly, at least partially disposed in the housing; the circuit board assembly is connected to the motor to control the motor; the circuit board assembly comprises at least one heating portion, the heating portion generates a temperature rise when the power tool is running; an active heat dissipation assembly, at least dissipating heat for the circuit board assembly; the active heat dissipation assembly is configured to use vibration motion to guide fluid flow so that the fluid flows through the surface of at least one heating portion to extract heat from the at least one heating portion.

[0008] In some embodiments, the power of the circuit board assembly is greater than or equal to 2W; and the maximum output power of the power tool is greater than or equal to 200W.

[0009] In some embodiments, the outer diameter of the motor is greater than or equal to 20 mm.

[0010] In some embodiments, the motor includes a drive shaft that rotates about a drive axis, and the drive shaft drives an output part to output power to achieve the function of the power tool.

[0011] In some embodiments, a fan is further included. The fan is formed on or connected to the drive shaft, and the fan rotates to form an air path for dissipating heat inside the power tool.

[0012] In some embodiments, the housing includes at least one vent that allows fluid communication with an environment external to the power tool.

[0013] In some embodiments, the circuit board assembly includes a circuit board body, the heat generating portion is disposed on the circuit board body, and the active heat dissipation assembly is connected to the circuit board body and is in thermal contact with the circuit board body.

[0014] In some embodiments, the active heat dissipation assembly is attached to components of the non-heat generating portion near the circuit board body.

[0015] In some embodiments, the active heat dissipation assembly is attached to a housing outside the circuit board body.

[0016] In some embodiments, the active heat dissipation component is disposed on the circuit board body.

[0017] In some embodiments, the active heat dissipation component does not contact the heat generating portion.

[0018] In some embodiments, a plurality of active heat dissipation components are provided.

[0019] In some embodiments, the active heat dissipation component has a thickness of no more than two millimeters.

[0020] In some embodiments, the active heat dissipation assembly includes a cooling element and a support structure supporting the cooling element, and the cooling element is driven to induce a vibration motion of a certain frequency.

[0021] In some embodiments, the active heat dissipation assembly further includes an orifice plate having one or more orifices, the orifice plate being disposed between the cooling element and a surface of the one or more heat generating portions.

[0022] A lighting device comprises: a lamp holder assembly, the lamp holder assembly comprising a lighting lamp; a power supply, at least supplying power to the lamp holder assembly; a supporting shell, at least supporting the lighting lamp; a circuit board assembly, at least partially disposed in the supporting shell; the circuit board assembly is connected to the lamp holder assembly to control the lighting lamp; the circuit board assembly comprises at least one heating portion, the heating portion generates a temperature rise when the lamp holder assembly is in operation; an active heat dissipation assembly, at least dissipating heat for one of the lighting lamp or the circuit board assembly; the active heat dissipation assembly is configured to use vibration motion to guide fluid flow so that the fluid flows through the surface of at least one heating portion or the lighting lamp to extract heat from the at least one heating portion or the lighting lamp.

[0023] A battery pack for providing electrical energy to an electric tool; comprising: a battery pack shell, wherein the battery pack shell includes at least one heating portion that generates a temperature rise during the charging / discharging process of the battery pack; an electric tool interface, disposed in the battery pack shell and configured to couple with the electric tool; an active heat dissipation component, disposed in the battery pack shell; the active heat dissipation component is configured to use vibration motion to guide the flow of a fluid so that the fluid flows through the surface of at least one heating portion to extract heat from the at least one heating portion.

[0024] In some embodiments, it also includes: a battery cell, housed in a battery pack shell; the battery cell generates a temperature rise during the charging / discharging process of the battery pack, and an active heat dissipation component is arranged near at least one battery cell.

[0025] In some embodiments, the battery cell provides power to the active heat dissipation component.

[0026] In some embodiments, it also includes a circuit board assembly that is at least partially disposed in the battery pack housing; the circuit board assembly at least controls the discharge circuit; and the circuit board assembly includes at least one heat generating portion.

[0027] In some embodiments, the discharge circuit is electrically connected to the battery cell and the power tool interface, respectively. The discharge circuit is configured to transmit electrical energy to the power tool via the power tool interface. The discharge circuit is disposed on the circuit board assembly.

[0028] In some embodiments, an active heat dissipation assembly is formed on or connected to the circuit board assembly.

[0029] In some embodiments, the battery pack housing includes at least one vent that allows fluid communication with an environment external to the battery pack.

[0030] In some embodiments, the battery pack provides a nominal voltage between greater than or equal to 12V and less than or equal to 100V.

[0031] In some embodiments, the nominal voltage of each battery cell is greater than or equal to 3.6V, and the average discharge current of the battery pack is greater than or equal to 20 amperes (A).

[0032] In some embodiments, the capacity of each battery cell is greater than or equal to 1.5 ampere hours (Ah).

[0033] A charger for charging a battery pack, comprising: a charger housing; a battery pack interface, disposed in the charger housing, the battery pack interface being configured to couple with the battery pack; a circuit board assembly, at least partially disposed in the housing; the circuit board assembly comprising at least one heat generating portion, the heat generating portion generating a temperature rise when the charger charges the battery pack; an active heat dissipation assembly, disposed in the charger housing; the active heat dissipation assembly being configured to use vibration motion to guide fluid flow so that the fluid flows through the surface of at least one heat generating portion to extract heat from the at least one heat generating portion.

[0034] In some embodiments, the charger has a charging voltage of at least 12V.

[0035] In some embodiments, the charger has a charging power of at least 20 W.

[0036] In some embodiments, it also includes: a charging circuit configured to be electrically connected to the battery pack interface and charge the battery pack; the charging circuit includes a switching element, and the switching frequency of the switching element is greater than or equal to 20kHz.

[0037] In some embodiments, the heat generating portion includes a power semiconductor device or a transformer.

[0038] In some embodiments, the charger housing includes at least one vent that allows fluid communication with an environment external to the charger.

[0039] In some embodiments, the charger housing includes a mounting structure capable of mounting the battery pack to a mounting position, the mounting structure including a locking portion for holding the battery pack in the charger and a guide portion for guiding an installation path of the battery pack.

[0040] In some embodiments, the circuit board assembly includes a circuit board body, the heat generating portion is disposed on the circuit board body, and the active heat dissipation assembly is connected to the circuit board body and is in thermal contact with the circuit board body.

[0041] In some embodiments, the circuit board assembly includes a circuit board body, a heat generating portion is disposed on the circuit board body, an active heat dissipation assembly is disposed on the circuit board body, and the active heat dissipation assembly is disposed close to the heat generating portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 is a structural diagram of the first embodiment of the present application; Figure 2 It is an example diagram of a power tool, a lighting device, a battery pack, and a charger; Figure 3 yes Figure 1 A schematic diagram of a cross-sectional view of; Figure 4a-4c is a diagram showing an example of the structure of an active heat dissipation component; Figure 5It is a structural example diagram of a circuit board assembly; Figure 6 is another example diagram of a circuit board assembly; Figure 7 is an electrical structure diagram of an embodiment of the present application; Figure 8a-8b is a structural diagram of the second embodiment of the present application; Fig. 9 yes Figure 8a Exploded diagram of Fig.10 is a structural diagram of a charger and a battery pack in the third embodiment of the present application; Fig.11 is a structural diagram of a charger in the third embodiment of the present application; Fig.12 This is a structural diagram of another charger in the third embodiment of the present application; Fig.13 It is a structural diagram of another charger and another battery pack in the third embodiment of the present application. DETAILED DESCRIPTION

[0043] Before any embodiments of the application are explained in detail, it is to be understood that the application is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the above drawings.

[0044] In this application, the terms "comprises", "includes", "has" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device that includes a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of more restrictions, an element defined by the sentence "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device that includes the element.

[0045] In this application, the term "and / or" is a description of the association relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects before and after are in an "and / or" relationship.

[0046] In the present application, the terms "connect", "combine", "couple", and "install" may refer to direct connection, combination, coupling, or installation, or indirect connection, combination, coupling, or installation. For example, direct connection refers to two parts or components being connected together without the need for an intermediate piece, and indirect connection refers to two parts or components being connected to at least one intermediate piece respectively, and the two parts or components being connected via the intermediate piece. In addition, "connect" and "couple" are not limited to physical or mechanical connections or couplings, and may include electrical connections or couplings.

[0047] In this application, it will be understood by those of ordinary skill in the art that relative terms (e.g., "about," "approximately," "substantially," etc.) used in conjunction with quantities or conditions include the values ​​and have the meaning indicated by the context. For example, the relative terms include at least the degree of error associated with the measurement of a specific value, the tolerances caused by manufacturing, assembly, and use associated with a specific value, etc. Such terms should also be considered to disclose a range defined by the absolute values ​​of the two endpoints. Relative terms may refer to plus or minus a certain percentage (e.g., 1%, 5%, 10% or more) of the indicated value. Numerical values ​​that do not use relative terms should also be disclosed as specific values ​​with tolerances. In addition, "substantially" may refer to plus or minus a certain degree (e.g., 1 degree, 5 degrees, 10 degrees or more) on the basis of the indicated angle when expressing a relative angular position relationship (e.g., substantially parallel, substantially perpendicular).

[0048] In this application, it will be understood by those skilled in the art that the function performed by a component can be performed by one component, multiple components, one part, or multiple parts. Similarly, the function performed by a part can also be performed by one part, one component, or a combination of multiple parts.

[0049] In the present application, the terms "upper", "lower", "left", "right", "front", "back" and other directional words are described based on the orientation and positional relationship shown in the accompanying drawings, and should not be understood as limiting the embodiments of the present application. In addition, in the context, it is also necessary to understand that when it is mentioned that an element is connected to another element "upper" or "lower", it can not only be directly connected to another element "upper" or "lower", but also indirectly connected to another element "upper" or "lower" through an intermediate element. It should also be understood that the directional words such as upper side, lower side, left side, right side, front side, back side, etc. not only represent the positive orientation, but can also be understood as the lateral orientation. For example, the bottom can include directly below, lower left, lower right, lower front, and lower back, etc.

[0050] In this application, the terms "controller", "processor", "central processing unit", "CPU", and "MCU" are interchangeable. When a unit "controller", "processor", "central processing unit", "CPU", or "MCU" is used to perform a specific function, unless otherwise specified, these functions can be performed by a single unit or multiple units.

[0051] In the present application, the terms “device”, “module” or “unit” may be implemented in the form of hardware or software to achieve specific functions.

[0052] In this application, the terms "calculate", "judge", "control", "determine", "identify", etc. refer to the operations and processes of a computer system or similar electronic computing device (e.g., controller, processor, etc.).

[0053] like Figure 1-2 As shown, a power tool, wherein the power tool includes an active heat dissipation component 20. In this embodiment, the power tool is an impact wrench 100. In some embodiments, it can also be other hand-held tools, such as screwdrivers, electric drills, wrenches, impact drills, electric hammers, nail guns, sanders, reciprocating saws, jig saws, circular saws, angle grinders, and angle tools. In some embodiments, it can also be garden tools, such as lawn mowers, hair dryers, and rear-walking power tools such as lawn mowers, chain saws, and cleaning machines. In some embodiments, it can also be bench-type tools, such as table saws, miter saws, etc. Alternatively, the power tool can also be other power tools, such as fans, photoelectric detection equipment, etc. Or non-road walking equipment, such as multi-purpose vehicles, can also be beach cars, UTVs (farmer cars), golf carts, all-terrain vehicles (ATVs), and can also be agricultural machinery vehicles, such as harvesters, sprayers, etc.

[0054] like Figures 1 to 7 As shown, an impact wrench 100 is taken as an example. The impact wrench 100 includes a power supply 30. Among them, in this embodiment, the power supply 30 is a DC power supply. The DC power supply is used to provide electrical energy to the impact wrench 100. The DC power supply is a battery pack, and the battery pack cooperates with the corresponding power supply circuit to power the impact wrench 100. Those skilled in the art should understand that the power supply 30 is not limited to the scenario of using a DC power supply, and can also be powered by AC power, AC power, and corresponding rectification, filtering and voltage regulation circuits to realize power supply to the corresponding components in the machine. In the subsequent description, the battery pack 30 will be used instead of the power supply, but it cannot be used as a limitation of the present invention.

[0055] The impact wrench 100 includes a housing 11, a motor 12, an output unit 13, and a circuit board assembly 17. The motor 12 includes a drive shaft 121 that rotates about the first axis 101. In the present embodiment, the motor 12 is specifically configured as an electric motor, and the motor 12 will be used to replace the motor, and the motor shaft 121 will be used to replace the drive shaft, but this cannot be used as a limitation to the present application.

[0056] The housing 11 includes a motor housing 111 for accommodating the motor and an output housing 112 for accommodating at least part of the output unit 13. The output housing 112 is connected to the front end of the motor housing 111. In this embodiment, the housing is also formed or connected with a grip for user operation, which is convenient for the user to hold and operate. A battery pack is connected to one end of the grip.

[0057] The output part 13 is used to drive the functional element to realize the function of the power tool. In the present embodiment, the output part 13 includes an output shaft 131. In some embodiments, a transmission assembly 14 is connected between the output part 13 and the motor 12, for example, a high-speed and high-torque output tool such as a screwdriver, a drill, or a saw. The output power of the motor 12 is transmitted to the output part 13 through the transmission assembly 14, and the output part 13 drives the functional element to complete the processing of the workpiece. In some embodiments, the motor 12 directly drives the output part 13, such as a fan, a hair dryer, a lawn mowing tool, a cleaning tool, etc., and the output part 13 drives the functional element (such as a fan blade, a blower, a cutting piece, or a water gun) to complete the processing or treatment of the workpiece.

[0058] The circuit board assembly 17 is connected to the motor 12 to control the operation of the motor 12. It can be understood that the connection between the circuit board assembly 17 and the motor 12 includes an electrical connection between the circuit board assembly 17 and the motor 12, and also includes a communication connection between the circuit board assembly 17 and the motor 12, and the communication connection is, for example, connected by digital signals, connected by analog signals, and connected by wireless signals. In this embodiment, the circuit board assembly 17 includes at least one heating portion 17a, and the heating portion 17a will generate a temperature rise when the impact wrench 100 is running.

[0059] The housing 11 is formed with a containing space, and the motor 12 and the circuit board assembly 17 are at least partially disposed in the housing 11. In the related art, at least one fan 123 is disposed in the housing 11 to dissipate heat for the motor 12 and the circuit board assembly 17. In some embodiments, the fan 123 is formed or connected to the motor shaft 121, and when the motor 12 starts working, the fan 123 also rotates according to certain preset rules. The rotation of the fan 123 forms an air path for dissipating heat inside the housing 11. However, as the output performance requirements for power tools are getting higher and higher, the requirements for heat dissipation of the equipment are also getting higher and higher. In some embodiments, the distance between the fan 123 and the circuit board assembly 17 is relatively far, for example Figure 3As shown, the motor 12 and the fan 123 are arranged in the motor housing 111, and the circuit board assembly 17 is arranged at the position where the grip 113 is connected to the battery pack 30. A plurality of wires 124 are arranged between the motor 12 and the circuit board assembly 17 to achieve the connection, which blocks the cooling effect of the heat dissipation air path generated by the fan 123 on the circuit board assembly 17 to a certain extent.

[0060] When using the fan 123 to dissipate heat, generally, to improve the heat dissipation effect, the number of fans 123 is increased, the speed of the fan 123 is increased, or the size of the fan 123 is increased. These may cause the fan 123 to be noisy, the product volume to be increased, and the loss of the motor 12 to be increased.

[0061] In the related art, there are also some components that add heat sinks such as heat sinks, heat pipes or heat spreaders to the circuit board assembly 17 to transfer heat away. Although the heat sink alleviates the temperature rise at the hot spot to a certain extent, it may not fully solve the heat generated in current and future devices. Similarly, the heat provided by the heat pipe or heat spreader may not be enough to remove the excessive heat generated.

[0062] In this embodiment, an active heat dissipation component 20 is provided to dissipate heat for the circuit board assembly 17. The active heat dissipation component 20 is formed or connected to the circuit board assembly 17. The active heat dissipation component 20 is configured to guide the flow of a fluid using a vibration motion, and the fluid is directed toward the surface of at least one heat generating portion 17a to extract heat from at least one heat generating portion 17a.

[0063] like Figures 4a to 4c As shown, the active heat dissipation assembly 20 includes a top plate 24 having an air outlet 241 therein, a cooling element 21 , an orifice plate 23 having an orifice 231 therein, and a support structure 22 .

[0064] The active heat dissipation component 20 includes a cooling element 21 that is connected to the fluid and is configured to use a vibration motion to guide the fluid toward the surface of one or more heat generating parts 17a. Heat is transferred from the heat generating part 17a to the fluid. The vibration here includes reciprocating motion in one direction, including motion in the same direction and motion out of phase at both ends.

[0065] The heat dissipation system composed of the active heat dissipation component 20 is configured so that the fluid follows a path from the surface of one or more heat-generating parts 17a through a structure whose temperature is lower than the surface of the heat-generating part 17a. The structure absorbs heat from the fluid. The structure is within the system and away from the active heat dissipation component 20.

[0066] The heat dissipation system may include at least one vent 114, 115 that allows fluid communication with the external environment. Therefore, the heat dissipation system can be an open system. The heat dissipation system is configured so that the fluid passes through the structure along the surface of one or more heat generating parts 17a and leaves the system to the external environment through one or more vents. For example, the system may include an air inlet 114 and an air outlet 115. The fluid can enter through the air inlet 114, travel to the active heat dissipation component 20 and be driven toward the surface of the heat generating part 17a. The fluid therefore passes through the structure and passes through the air outlet 115 along the surface of one or more heat generating parts 17a.

[0067] The cooling element 21 of the active heat dissipation component 20 includes a first side and a second side. The first side is at the far side of one or more heat generating parts 17a and is in communication with the fluid. The second side is close to one or more heat generating parts 17a. The cooling element 21 is configured to use a vibration motion to guide the fluid from the first side to the second side so that the fluid is driven toward the surface of the one or more heat generating parts 17a.

[0068] In some embodiments, the active heat dissipation assembly 20 further includes a support structure 22. The cooling element 21 is supported by the support structure 22. The cooling element 21 is supported by the support structure 22 in a central region of the active heat dissipation assembly 20.

[0069] The active cooling system may further include an orifice plate 23 having one or more orifices 231 therein. The orifice plate 23 is disposed between the cooling element 21 and the surface of the one or more heat generating portions 17a. The cooling element 21 is actuated or driven to drive the fluid through the one or more orifices 231. The fluid flows from the one or more orifices 231 to the surface of the one or more heat generating portions 17a.

[0070] In some embodiments, the tip of the cooling element 21 comprises a portion of the periphery farthest from the support structure 22 and experiences the greatest deflection during actuation of the cooling element 21 .

[0071] Figure 4a The active heat sink assembly 20 is depicted in an intermediate position. Thus, the cooling element 21 is shown as being substantially flat. For in-phase operation, the cooling element 21 is driven to Figure 4b and 4cThe active heat dissipation assembly 20 is further configured to cause little or no fluid to be drawn back through the orifice 132 by the vibrating motion of the cooling element 21.

[0072] In some embodiments, the thickness H of the active heat dissipation component 20 does not exceed two millimeters.

[0073] In some embodiments, the active heat dissipation component 20 can be a cooling system of a microelectromechanical system (MEMS). The system includes a plurality of cooling units. Each cooling unit includes a cooling element 21 in communication with a fluid. The active heat dissipation component 20 includes an orifice plate 23 having one or more orifices therein. The orifice plate 23 is disposed between the cooling element 21 and the surface of one or more heat generating parts 17a. The cooling element 21 is actuated or started to drive the fluid through the one or more orifices. The fluid flows from the one or more orifices to the surface of one or more heat generating parts 17a. The cooling element 21 of the active heat dissipation component 20 is driven to cause a vibration motion of a certain frequency. The cooling element 21 is in communication with the fluid and is configured to use a vibration motion to guide the fluid toward the surface of one or more heat generating structures to extract heat from one or more heat generating parts 17a. The method also includes guiding the fluid along a path from the surface of one or more heat generating structures through a structure having a temperature lower than the surface of the heat generating part 17a. The structure is within the system, away from the active cooling system and absorbs heat from the fluid. In some embodiments, the fluid is guided to pass through the path of the component from the surface of one or more heat generating parts 17a and return to the active heat dissipation component 20. In some embodiments, the fluid is directed to follow a path from the surface of at least one heat generating portion 17a, through the component, and exit the system through at least one vent to the external environment.

[0074] The thickness H of the active heat dissipation component 20 may be less than 2 mm. In some embodiments, the thickness H of the active heat dissipation component 20 does not exceed 1.5 mm. In some embodiments, the thickness H does not exceed 1.1 mm. In some embodiments, the thickness H does not exceed one millimeter. In some embodiments, the thickness H does not exceed two hundred and fifty micrometers. In some embodiments, the distance y between the bottom of the orifice plate 23 and the top of the heating portion 17a may be very small. In some embodiments, y is at least two hundred micrometers and does not exceed one millimeter. In some embodiments, y is at least two hundred micrometers and does not exceed three hundred micrometers.

[0075] Although one active heat dissipation assembly 20 (e.g., one cooling unit) is shown, multiple active heat dissipation assemblies 20 may be used in conjunction with the heat generating portion 17a. For example, a one-dimensional or two-dimensional array of cooling units may be utilized. The cooling element 21 has a first side away from the heat generating portion 17a and a second side close to the heat generating portion 17a. The first side of the cooling element 21 is the top of the cooling element 21 (closer to the top plate) and the second side is the bottom of the cooling element 21 (closer to the orifice plate 23). The cooling element 21 is actuated to perform a vibrating motion. The vibrating motion of the cooling element 21 drives the fluid from the first side of the cooling element 21 away from the heat generating portion 17a to the second side of the cooling element 21 close to the heat generating portion 17a.

[0076] In some embodiments, piezoelectricity is used to actuate the cooling element 21. Therefore, the cooling element 21 can be a piezoelectric cooling element 21. The cooling element 21 can be driven by a piezoelectric mounted on or integrated into the cooling element 21. In some embodiments, the cooling element 21 is driven in another way, including but not limited to providing piezoelectricity on another structure in the active heat dissipation component 20. The cooling element 21 and similar cooling elements 21 are referred to as piezoelectric cooling elements 21 below, although mechanisms other than piezoelectricity can be used to drive the cooling element 21. In some embodiments, the cooling element 211 includes a piezoelectric layer on a substrate. The substrate can be a stainless steel, nickel alloy and / or Hastelloy substrate. In some embodiments, the piezoelectric layer includes a plurality of sublayers formed as a thin film on the substrate. In other embodiments, the piezoelectric layer can be a bulk layer fixed to the substrate. Such a piezoelectric cooling element 21 also includes an electrode for activating the piezoelectric element. In some embodiments, the substrate is used as an electrode. In other embodiments, a bottom electrode can be provided between the substrate and the piezoelectric layer.

[0077] like Figures 5 to 7As shown, in this embodiment, the motor 12 includes a stator winding and a rotor. In some embodiments, the motor 12 is a three-phase brushless motor 12, including a rotor with a permanent magnet and a three-phase stator winding U, V, W that is electronically commutated. In some embodiments, the three-phase stator windings U, V, and W are connected in a star shape, and in other embodiments, the three-phase stator windings U, V, and W are connected in an angle shape. However, it must be understood that other types of brushless motors are also within the scope of the present disclosure. The brushless motor may include less than or more than three phases. In this embodiment, the nominal voltage of the motor 12 is greater than or equal to 12V. In some embodiments, the nominal voltage of the motor 12 is greater than or equal to 12V and less than or equal to 60V. In some embodiments, the nominal voltage of the motor 12 is greater than or equal to 3V and less than or equal to 60V. In some embodiments, the nominal voltage of the motor 12 is greater than or equal to 14V and less than or equal to 80V. In some embodiments, the nominal voltage of the motor 12 is greater than or equal to 20V and less than or equal to 80V. In this embodiment, the outer diameter of the motor 12 is greater than or equal to 20mm. In some embodiments, the outer diameter of the motor 12 is greater than or equal to 30 mm. In some embodiments, the outer diameter of the motor 12 is greater than or equal to 30 mm and less than or equal to 100 mm.

[0078] The circuit board assembly 17 includes: a printed circuit board (PCB) and a flexible printed circuit (FPC). The circuit board assembly 17 includes a circuit board body 171. In this embodiment, the circuit board body 171 is a substrate, such as a copper-clad laminate, a ceramic board, and an enamel-coated steel substrate. The circuit board assembly 17 also includes a plurality of electronic components disposed on the circuit board body 171. At least some of the electronic components are heating parts 17a. The electronic components include: a controller 172 and a switch circuit 173. Among them, the switch circuit 173 is electrically connected to the stator windings U, V, and W of the motor 12, and is used to transfer current from a power supply such as a battery pack 30 to the stator windings U, V, and W to drive the motor 12 to rotate. In one embodiment, the switch circuit 173 includes a plurality of switch elements Q1, Q2, Q3, Q4, Q5, and Q6. The gate terminal of each switch element is electrically connected to the controller 172 for receiving a control signal from the controller 172. The drain or source of each switching element is connected to the stator windings U, V, and W of the motor 12. The switching elements Q1-Q6 receive control signals from the controller 172 to change their respective conduction states, thereby changing the current loaded on the stator windings U, V, and W of the motor 12 by the power supply, such as the battery pack 30. In one embodiment, the switching circuit 173 can be a three-phase bridge driver circuit including six controllable semiconductor power devices (such as field effect transistors (Field Effect Transistor, FET), bipolar junction transistors (Bipolar Junction Transistor, BJT), insulated gate bipolar transistors (Insulated Gate Bipolar Transistor, IGBT), etc.). It can be understood that the above-mentioned switching elements can also be any other type of solid-state switches, such as IGBT, BJT, etc.

[0079] The controller 172 is used to control the motor 12. The controller 172 uses a dedicated control chip, such as a single chip microcomputer or a microcontroller unit (MCU). The controller 172 specifically controls the on or off state of the switch element in the switch circuit 173 through the control chip. In some embodiments, the controller 172 controls the ratio between the on time and the off time of the drive switch based on a pulse width modulation (PWM) signal. It should be noted that the control chip can be integrated into the controller 172, or can also be set independently of the controller 172. As for the structural relationship between the control chip and the controller 172, this embodiment does not limit it.

[0080] In some embodiments, the heating portion 17 a further includes: a resistor, a capacitor, a semiconductor device, and other electronic components disposed on the circuit board body 171 .

[0081] In this embodiment, the power of the circuit board assembly 17 is greater than or equal to 2 W. In some embodiments, the power of the heat generating portion 17a in the circuit board assembly 17 is greater than or equal to 2 W. In some embodiments, the power of the circuit board assembly 17 is greater than or equal to 3 W.

[0082] The output power of the impact wrench 100 is greater than or equal to 200 W. In some embodiments, the output power of the impact wrench 100 is greater than or equal to 300 W. In some embodiments, the output power of the impact wrench 100 is greater than or equal to 400 W.

[0083] As an implementation of this embodiment, the active heat dissipation component 20 is connected to the circuit board body 171 and is in thermal contact with the circuit board body 171. As an embodiment, the active heat dissipation component 20 is close to one side of the circuit board body 171. The cooling element 21 in the active heat dissipation component 20 is not in actual contact with the circuit board body 171. In this embodiment, the active heat dissipation component 20 is attached to a component of a non-heat-generating portion near the circuit board body 171. For example, the active heat dissipation component 20 can be attached to the housing 11 near the circuit board body 171. The heat generated by the heat-generating portion 17a is transferred to the circuit board body 171, and the injection channel formed between the vents 114, 115 on the housing 11 and the circuit board body 171 corresponds to other heat-generating portions 17a on the circuit board body 171 and / or the circuit board assembly 17, so that the fluid can be maintained and allowed to flow.

[0084] like Figure 6 As described above, as a replaceable embodiment, the active heat dissipation component 20 is arranged on the circuit board body 171 and is in actual contact with the circuit board body 171. Optionally, multiple active heat dissipation components 20 are provided or are provided to match the number of the heating portion 17a. The active heat dissipation component 20 is arranged at a position close to the heating portion 17a. The active heat dissipation component 20 does not contact the heating portion 17a. In the present embodiment, the active heat dissipation component 20 is attached to the vicinity of the heating portion 17a. For example, a support frame is provided to support the cooling element 21. The fluid driven by the active heat dissipation component 20 directly dissipates heat for the heating portion 17a, and optionally, the fluid driven by the active heat dissipation component 20 flows directly through the heating portion 17a. The injection channel formed between the vents 114, 115 on the housing 11 and the heating portion 17a corresponds to the heating portion 17a, so that the fluid flow can be maintained and allowed.

[0085] In this embodiment, the housing 11 includes at least one vent, and the vents 114 and 115 allow fluid to circulate with fluid in the environment outside the power tool. In this embodiment, the vent 114 operates as an air inlet, and the vent 115 operates as an air outlet.

[0086] The cooler fluid (e.g., air) near the active heat dissipation assembly 20 is sucked toward one or more cooling elements 21. Optionally, the fluid from the air inlet 114 moves toward the one or more cooling elements 21. The one or more cooling elements 21 drive the fluid to move from a side away from the circuit board body 171 or the heating portion 17a to a side close to the circuit board body 171 or the heating portion 17a. Therefore, the fluid is driven and contacts the circuit board body 171 or the heating portion 17a. The heat of the circuit board body 171 or the heating portion 17a is transferred to the fluid. The fluid flows along the circuit board body 171 or the heating portion 17a and leaves the area near the circuit board body 171 or the heating portion 17a, taking away heat from the circuit board body 171 or the heating portion 17a. Therefore, the fluid carrying heat from the circuit board body 171 or the heating portion 17a can be discharged from the inside of the impact wrench 100, and the cooler fluid is sucked from the external environment through the air inlet 114 to cool the heating portion 17a. In addition, since the fluid is directed to the outlet 115 away from the one or more cooling elements 21, in this process, heat can be transferred to and dissipated by one or more structures in a predetermined path. For example, the temperature may be lower than the heat generating portion 17a and / or lower than the fluid carrying the heat from the heat generating portion 17a. For example, the heat can be transferred to the housing 11. Therefore, the fluid can be at least slightly cooled before leaving the impact wrench 100. In some embodiments, the fluid passes through a sufficient number or configuration of one or more low-temperature structures and / or a sufficient distance so that at least ninety percent of the heat is removed from the fluid. In some embodiments, the fluid passes through a sufficient number and / or configuration of one or more low-temperature structures and / or a sufficient distance so that at least eighty percent of the heat is removed from the fluid. In some embodiments, the fluid passes through a sufficient number and / or configuration of one or more low-temperature structures and / or a sufficient distance so that at least fifty percent of the heat is removed from the fluid. Other amounts of heat can be dissipated in other embodiments. In some embodiments, the impact wrench 100 also includes grooves or guides in the pipe and / or housing for guiding the flow of the fluid. In some embodiments, the path of the fluid may include a heat sink or other mechanism for heat dissipation. For example, a metal plate is provided inside the housing 11 for heat dissipation. Therefore, heat can be effectively removed from the impact wrench 100 .

[0087] like Figure 2As shown, as an alternative embodiment, the power tool is a lighting device 50. The output part 53 is a functional element that is not driven by a motor, such as a light source, including a lighting light source, a laser, etc. The lighting device 50 is not provided with a motor. The lighting device 50 includes a circuit board assembly for controlling the lighting light source. The lighting device 50 also includes a battery pack 30 for powering it.

[0088] like Figure 2 , Figures 8a to 9 As described above, as a second embodiment of the present application, a battery pack 30 is involved. The battery pack 30 supplies power to the above-mentioned power tool (including a tool with a motor and a lighting device). The power tool includes an output unit 13. In this embodiment, the power tool is the same or similar to the first embodiment, and a detailed description is omitted here for the purpose of brevity of the specification.

[0089] The battery pack 30 provides a nominal voltage greater than or equal to 10V and less than or equal to 80V. The battery pack 30 includes: a battery pack housing 31 and a power tool interface 32. The power tool interface 32 is provided in the battery pack housing 31, and the power tool interface 32 is configured to couple with the power tool. When the battery pack 30 is attached to the power tool, the power tool interface 32 is coupled to the terminal block (not shown) of the power tool. The battery pack 30 provides a discharge current to the power tool through the power tool interface 32. Figure 8b As shown, the battery pack 30B is a large-capacity, high-voltage battery pack. Optionally, the nominal voltage of the battery pack 30B may be greater than or equal to 20V and less than or equal to 100V, for example, the nominal voltage of the battery pack may be 24V, 40V, 56V, 80V, etc. The average discharge current of the battery pack is greater than or equal to 20 amperes (A).

[0090] In this embodiment, the battery pack housing 31 includes at least one heating portion that generates a temperature rise during the charging / discharging process of the battery pack 30. For the convenience of distinction, the heating portion here is referred to as a second heating portion.

[0091] The active heat dissipation assembly 20 is disposed in the battery pack housing 31. The active heat dissipation assembly 20 is configured to guide the flow of the fluid using a vibration motion, and the fluid is directed toward the surface of the at least one second heat generating portion to extract heat from the at least one second heat generating portion.

[0092] The working principle of the active heat dissipation assembly 20 is substantially the same as that of the active heat dissipation assembly in the first embodiment, and its specific structure and size are appropriately adjusted according to the differences between the battery pack 30 and the power tool.

[0093] In this embodiment, the second heating part includes a battery cell 33. The battery cell 33 is contained in the battery pack housing 31. The battery cell 33 generates a temperature rise during the charging / discharging process of the battery pack 30, and the active heat dissipation component 20 is arranged near at least one battery cell 33. In this embodiment, the battery cell 33 provides electrical energy for the active heat dissipation component 20.

[0094] In some embodiments, the battery pack 30 is a 5S3P configuration, that is, a group of 5 battery cells 33 connected in series and 3 groups connected in parallel. The battery pack housing 31 surrounds the battery cells 33. In some embodiments, as Fig. 9 As shown, the battery pack 30 is a 5S2P configuration, that is, a group of 5 battery cells 33 connected in series, and 2 groups connected in parallel. In other embodiments, other combinations of battery cells 33 in the battery pack 30 are also possible. The nominal voltage of each battery cell 33 is greater than or equal to 3V. In some embodiments, the nominal voltage of the battery cell 33 is greater than or equal to 3.6V. The nominal capacity of each battery cell 33 is greater than or equal to 1.5 ampere hours (Ah). In some embodiments, the nominal capacity of each battery cell 33 is greater than or equal to 3 ampere hours (Ah).

[0095] The battery cells 33 may be any rechargeable battery cell chemistry type, such as lithium (Li), lithium ion (Li-ion), other lithium-based chemistries, nickel cadmium (NiCd), nickel metal hydride (NiMH), and the like.

[0096] In some embodiments, the battery pack 30 further includes a circuit board assembly. For the convenience of distinction, a second circuit board assembly 37 is used to refer to it. The second circuit board assembly 37 is at least partially disposed in the battery pack housing 31. The second circuit board assembly 37 is used to control a discharge circuit. The discharge circuit is electrically connected to the battery cell 33 and the power tool interface 32, respectively, and the discharge circuit is configured to transmit electrical energy to the power tool via the power tool interface 32. The discharge circuit is disposed on the second circuit board assembly 37.

[0097] At least some of the devices on the second circuit board assembly 37 belong to the second heating part. The second circuit board assembly 37 includes a circuit board body 171. In the present embodiment, the circuit board body 171 is a substrate, for example, a copper-clad laminate, a ceramic board, and an enamel-coated steel substrate. The circuit board assembly 17 also includes a plurality of electronic components arranged on the circuit board body 171. At least some of the electronic components are the second heating part. The second heating part includes a single-chip microcomputer, a microcontroller unit (MCU), a controllable semiconductor power device, a field effect transistor (FET), a bipolar junction transistor (BJT), an insulated gate bipolar transistor (IGBT), a resistor, a capacitor, and other semiconductor devices.

[0098] In this embodiment, the battery pack housing 31 includes at least one vent 311 , 312 , which allows fluid to flow between the fluid and the external environment of the power tool.

[0099] As an implementation mode of this embodiment, the second heating part takes the battery cell 37 as an example, and the active heat dissipation component 20 is connected to the battery cell 37 and is in thermal contact with the battery cell 37. As an embodiment, the active heat dissipation component 20 is close to one side of the battery cell 37. The cooling element 21 in the active heat dissipation component 20 is not in actual contact with the battery cell 37. In this embodiment, the active heat dissipation component 20 is attached to the vicinity of the battery cell 37. For example, the active heat dissipation component 20 can be attached to the battery pack housing 31 near the battery cell 37. The heat generated by the battery cell 37, the injection channel formed between the vents 311, 312 on the battery pack housing 31 and the battery cell 37, the injection channel corresponds to the battery cell 37, so that the fluid can be maintained and allowed to flow.

[0100] As an alternative embodiment, the active heat dissipation component 20 is disposed on the battery cell 37 and is in actual contact with the battery cell 37, such as Fig. 9 As shown, the active heat dissipation component 20 is attached to the surface of the battery core 37. Optionally, multiple active heat dissipation components 20 are provided or are provided to adapt to the number of battery cores 37.

[0101] As two implementation methods of this embodiment, the second heating part takes a circuit board assembly as an example, and the arrangement of the active heat dissipation assembly 20 and the circuit board assembly is as follows: Figure 5 and Figure 6 Public content.

[0102] The battery pack housing 31 is provided with vents 311 and 312. In this embodiment, the vent 311 is used as an air inlet, and the vent 312 is used as an air outlet.

[0103] like Figures 10 to 13 As the third embodiment of the present application, a charger 400 is involved. The charger 400 is used to charge the battery pack 30. The charger 400 includes: a charger housing 41, a battery pack interface 42 and a circuit board assembly 44. Among them, the battery pack interface 42 is arranged in the charger housing 41. The battery pack interface 42 is used to couple with the battery pack 30. The circuit board assembly 44 is at least partially arranged in the charger housing 41. The circuit board assembly 44 includes at least one heating part, and the heating part generates a temperature rise when the charger 400 charges the battery pack 30. Among them, for the convenience of reference, this circuit board assembly 44 is a third circuit board assembly 44, and this heating part is a third heating part. In this embodiment, the charger 400 also includes a power interface 43, and the power interface 43 is used to connect to a power source. In this embodiment, the power source can be selected as an AC power source, and the power interface 43 can be connected to 120V or 220V AC mains. The power interface 43 is connected to a power conversion circuit to convert the connected AC power into charging power suitable for charging the battery pack 30 and auxiliary power for powering the internal components of the charger 400. It is understandable that the power conversion circuit may include at least an AC / DC module. In an alternative implementation, the power interface 43 may be connected to a photovoltaic panel, and the power conversion circuit may convert light energy into charging power suitable for charging the battery pack 30 and auxiliary power for powering the internal components of the charger 400. It is understandable that the power conversion circuit may include an MPPT (Maximum Power Point Tracking, solar controller 172) module, i.e., a module that converts light energy into electrical energy. In this embodiment, the charger housing 41 is connected to a power cord plug as the power interface 43. In an alternative implementation, the power interface 43 may also be other forms of interfaces, which are not limited here.

[0104] like Fig.12 As shown, the nominal voltage of the battery pack 30B may be greater than or equal to 20V and less than or equal to 100V. For example, the nominal voltage of the battery pack 30B may be 24V, 40V, 56V, 80V, etc. The charger 400B charges the battery pack 30B.

[0105] like Fig.13 As shown, the charger 400C includes a plurality of battery pack interfaces 42C. That is, the charger 400c can charge a plurality of battery packs 30 at the same time.

[0106] In this embodiment, an active heat dissipation component 20 is further included, which is disposed in the charger housing 41. The active heat dissipation component 20 is configured to use vibration motion to guide the fluid to flow toward the surface of the at least one third heat generating portion to extract heat from the at least one third heat generating portion.

[0107] The third circuit board assembly 44 includes a circuit board body. In this embodiment, the circuit board body is a substrate, such as a copper-clad laminate, a ceramic board, and an enamel-coated steel substrate. The circuit board assembly 44 also includes a plurality of electronic components disposed on the circuit board body. At least some of the electronic components are the third heating portion.

[0108] As an implementation of this embodiment, the active heat dissipation component 20 is connected to the circuit board body 171 and is in thermal contact with the circuit board body. As an alternative embodiment, the active heat dissipation component 20 is disposed on the circuit board body.

[0109] In this embodiment, the charger 400 has a charging voltage of at least 12 V. In some embodiments, the charger 400 has a charging voltage of at least 12 V to 100 V. In some embodiments, the charger 400 has a charging power of at least 20 W.

[0110] In this embodiment, the third circuit board assembly 44 is used to control the charging circuit. The charging circuit is configured to be electrically connected to the battery pack interface 42 and charge the battery pack 30. The charging circuit is disposed on the third circuit board assembly 44. The charging circuit includes a switching element, and the switching frequency of the switching element is greater than or equal to 20 kilohertz (kHz). In some embodiments, the switching frequency of the switching element is greater than or equal to 100 kilohertz (kHz). The switching circuit 173 can be a three-phase bridge driver circuit including six controllable semiconductor power devices (such as field effect transistors (Field Effect Transistor, FET), bipolar junction transistors (Bipolar Junction Transistor, BJT), insulated gate bipolar transistors (Insulated Gate Bipolar Transistor, IGBT), etc.). It is understandable that the above-mentioned switching element can also be any other type of solid-state switch, such as IGBT, BJT, etc.

[0111] In some embodiments, the third heating unit further includes a resistor, a capacitor, and a transformer. Optionally, the power conversion circuit is a transformer.

[0112] In some embodiments, the charger housing 41 includes a mounting structure capable of mounting the battery pack 30 to a mounting position, the mounting structure including a locking portion 441 for retaining the battery pack 30 in the charger 400 and a guide portion 442 for guiding the mounting path of the battery pack 30 .

[0113] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the above embodiments do not limit the present application in any form, and any technical solution obtained by equivalent replacement or equivalent transformation falls within the protection scope of the present application.

Claims

1. A power tool comprising: case; an output unit configured to output power; a motor, at least partially disposed in the housing; The motor drives the output unit; A power supply, for supplying power to at least the motor; A circuit board assembly is at least partially disposed in the housing; the circuit board assembly is connected to the motor to control the motor; the circuit board assembly includes at least one heating portion, and the heating portion generates a temperature rise when the power tool is running; An active heat dissipation component is used to dissipate heat for at least the circuit board component; the active heat dissipation component is configured to use vibration motion to guide the flow of fluid so that the fluid flows through the surface of at least one of the heat-generating parts to extract heat from at least one of the heat-generating parts.

2. The power tool according to claim 1, characterized in that: The power of the circuit board assembly is greater than or equal to 2W; the maximum output power of the power tool is greater than or equal to 200W.

3. The power tool according to claim 1, characterized in that: The motor includes a drive shaft rotating around a drive axis, the drive shaft drives the output part to output power to achieve the function of the power tool; and also includes a fan, the fan is formed or connected to the drive shaft, the fan rotates to form an air path for dissipating heat inside the power tool.

4. The power tool according to claim 1, characterized in that: The housing includes at least one vent that allows the fluid to communicate with fluid from an environment external to the power tool.

5. The power tool according to claim 1, characterized in that: The circuit board assembly comprises a circuit board body, the heat generating portion is arranged on the circuit board body, and the active heat dissipation assembly is connected to the circuit board body and is in thermal contact with the circuit board body.

6. The power tool according to claim 5, characterized in that: The active heat dissipation assembly is attached to components of the non-heat generating portion near the circuit board body.

7. The power tool according to claim 6, characterized in that: The active heat dissipation component is attached to a housing outside the circuit board body.

8. The power tool according to claim 7, characterized in that: The active heat dissipation component is arranged on the circuit board body.

9. The power tool according to claim 8, characterized in that: The active heat dissipation component does not contact the heat generating portion.

10. The power tool according to claim 1, characterized in that: The thickness of the active heat dissipation component does not exceed two millimeters.

11. The power tool according to claim 1, characterized in that: The active heat dissipation component includes a cooling element and a support structure supporting the cooling element, and the cooling element is driven to cause a vibration motion of a certain frequency.

12. A lighting device, comprising: A lamp cap assembly, the lamp cap assembly comprising a lighting lamp; A power supply, for supplying power to at least the lamp holder assembly; A supporting shell, at least supporting the lighting lamp; a circuit board assembly, at least partially disposed in the support housing; The circuit board assembly is connected to the lamp head assembly to control the lighting lamp; the circuit board assembly includes at least one heating part, and the heating part generates a temperature rise when the lamp head assembly is running; An active heat dissipation component is used to dissipate heat for at least one of the lighting lamp or the circuit board assembly; the active heat dissipation component is configured to use vibration motion to guide the flow of fluid so that the fluid flows through the surface of at least one of the heat-generating parts or the lighting lamp to extract heat from at least one of the heat-generating parts or the lighting lamp.

13. A battery pack for providing electric energy to an electric tool; comprising: A battery pack housing, wherein the battery pack housing includes at least one heat generating portion that generates a temperature rise during the charging / discharging process of the battery pack; A battery cell, contained in the battery pack housing; A power tool interface, disposed on the battery pack housing and configured to be coupled to the power tool; An active heat dissipation component is disposed in the battery pack housing; the active heat dissipation component is configured to use vibration motion to guide the flow of fluid so that the fluid flows through the surface of at least one of the heat-generating parts to extract heat from at least one of the heat-generating parts.

14. The battery pack according to claim 13, characterized in that: Also includes: The battery cells generate a temperature rise during the charging / discharging process of the battery pack, and an active heat dissipation component is disposed close to at least one of the battery cells.

15. The battery pack according to claim 14, characterized in that: The battery core provides electrical energy to the active heat dissipation component.

16. The battery pack according to claim 15, characterized in that: It also includes a circuit board assembly, which is at least partially disposed in the battery pack housing; the circuit board assembly at least controls a discharge circuit; and the circuit board assembly includes at least one of the heat generating parts.

17. The battery pack according to claim 16, characterized in that: The active heat dissipation assembly is formed on or connected to the circuit board assembly.

18. The battery pack according to claim 13, characterized in that: The battery pack housing includes at least one vent that allows fluid communication between the fluid and an environment outside the battery pack.

19. The battery pack according to claim 13, characterized in that: The battery pack provides a nominal voltage between greater than or equal to 12V and less than or equal to 100V.

20. A charger for charging a battery pack, comprising: Charger housing; A battery pack interface, disposed on the charger housing, the battery pack interface being configured to couple with the battery pack; A circuit board assembly is at least partially disposed in the shell; the circuit board assembly includes at least one heat generating portion, and the heat generating portion generates a temperature rise when the charger charges the battery pack; an active heat dissipation assembly is disposed in the charger shell; the active heat dissipation assembly is configured to use vibration motion to guide the flow of a fluid so that the fluid flows through the surface of at least one of the heat generating portions to extract heat from at least one of the heat generating portions.

21. The charger according to claim 20, characterized in that: The heat generating unit includes a power semiconductor device or a transformer.

22. The charger according to claim 20, characterized in that: The charger housing includes at least one vent that allows fluid communication between the fluid and an environment external to the charger.

23. The charger according to claim 20, characterized in that: The circuit board assembly comprises a circuit board body, the heat generating portion is arranged on the circuit board body, and the active heat dissipation assembly is connected to the circuit board body and is in thermal contact with the circuit board body.

24. The charger according to claim 20, characterized in that: The circuit board assembly comprises a circuit board body, the heat generating portion is arranged on the circuit board body, the active heat dissipation assembly is arranged on the circuit board body, and the active heat dissipation assembly is arranged close to the heat generating portion.

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