Charging system for an accumulator

Abstract

The present invention relates to a charging system for charging at least one accumulator for a mobile power tool, in particular an accumulator for a portable power tool, comprising: a housing that defines a charging chamber in which an accumulator can be charged at each of at least one charging interface, and a heat transfer device which is configured to transfer thermal energy between the charging chamber and outside of the housing.

Description

[0001] 2025ID00021

[0002] Hilti Aktiengesellschaft in Schaan

[0003] Principality of Liechtenstein

[0004] Charging system for a battery

[0005] AREA OF INVENTION

[0006] The present invention relates to a charging system for charging at least one accumulator for a mobile machine tool.

[0007] Mobile machine tools can be broadly divided into three main groups: quasi-stationary machine tools (e.g., core drills or portable table saws), portable machine tools (e.g., rotary hammers, circular saws, or hedge trimmers), and pushable machine tools (e.g., lawnmowers or polishing machines). Hybrid forms and other machine tools, such as construction robots, can also exist. In principle, all such machine tools can be powered by batteries, and for flexibility reasons, it is advisable to use standardized batteries, such as manufacturer-specified batteries. A mobile machine tool can be portable; for example, it can weigh less than 50 kg, and in particular less than 25 kg.

[0008] Charging such batteries near their place of use is advantageous to save walking distances. However, if the place of use is outdoors, the ambient temperature may be lower or higher than the permissible battery temperature range. The permissible battery temperature range can, for example, be from 0°C or 5°C to 35°C or 40°C. The ambient temperature can be influenced by factors such as:

[0009] Air temperature, for example, battery temperatures near and / or below freezing and / or above, for example, 40°C during charging or its start, may be undesirable.

[0010] solar radiation, which is particularly undesirable as an additional heat input during charging,

[0011] a storage temperature of the battery, for example in a vehicle, and / or residual heat of the battery as a result of a discharge operation.

[0012] Therefore, there is a need to cool and / or heat a battery. Similar conditions can also exist, for example, on a construction site during the shell construction phase. - 2 - 2025ID00021

[0013] One object of the present invention is therefore to provide a charging system for cooling and / or heating.

[0014] REVELATION OF THE INVENTION

[0015] Accordingly, a charging system for charging at least one accumulator for a mobile machine tool, in particular an accumulator for a portable machine tool, is proposed. The charging system comprises a housing and a heat exchanger. The housing defines a charging compartment in which an accumulator can be charged at at least one charging interface. The heat exchanger is designed to transfer heat energy between the charging compartment and the area outside the housing.

[0016] The heat exchanger device allows heat energy to be transported from the charging chamber to the outside in order to cool a battery in the charging chamber.

[0017] Additionally or alternatively, heat energy from outside can be transported into the charging chamber via the heat exchanger to heat a battery within the charging chamber. The housing separates the inside and outside, thus maintaining the temperature in the charging chamber.

[0018] The term "accumulator" can be understood as a storage device for electrical energy that is designed and intended for repeated, even partial, charging and discharging. The term "accumulator for a mobile machine tool" can be understood as an accumulator dimensioned for operating a machine tool with a nominal power of up to 10 kW, preferably up to 5 kW, and more preferably up to 2.5 kW. The term "accumulator for a mobile machine tool" can also be understood as an accumulator with a capacity of up to 50 Ah, and more preferably up to 20 Ah. The accumulator has a mating interface that is complementary to the charging interface; one can also speak of interfaces that are opposite to each other and / or functionally or geometrically negative to each other.

[0019] The accumulator is, for example, an accumulator device that has at least one accumulator cell or several accumulator cells, an accumulator housing surrounding the accumulator cell, and a mating interface arranged on the accumulator housing. The accumulator device may include a ventilation channel for ventilating the interior of the accumulator housing to cool and / or heat the accumulator cells. The accumulator device may have a control unit, which, for example, is used to... 3 - 2025ID00021

[0020] The device is configured to control the charging and / or discharging of the accumulator cells, for example, to prevent deep discharge of individual accumulator cells and / or to control the temperature distribution during charging and / or discharging. The control unit can be connected to at least one sensor in the accumulator device for data retrieval, for example, a voltage sensor and / or a temperature sensor. The ventilation channel can be arranged to allow airflow around at least a portion of the accumulator cell, preferably having one opening, and more preferably both openings, in the region of the mating interface.

[0021] The term "charging system" refers to a system in which the housing, charging interface, and heat exchanger are at least compatible. A battery may be part of the charging system, but each battery can be easily disconnected from the system as needed. The charging system may also include other components, such as a power cord or a charging interface for mechanical connection to a stacking system, like those found in so-called system tool cases.

[0022] The term "charging interface" can refer to a standardized and / or proprietary interface for connecting a battery. "Connection" generally refers to a mechanical, electrical, fluidic, and / or control-related connection. Specifically, in the case of a charging interface, "connection" is at least a mechanical and electrical connection. A "connected charging interface" means that a battery is connected to the charging interface via the charging interface and the corresponding interface. In this "connected charging interface" state, the battery may be charged by the charger.

[0023] The housing can be opened and closed. It may, for example, have a lid and / or a top and / or side flap. When closed, the housing, including the heat exchanger, may meet a protection rating of IPX4 or higher according to DIN EN 60529 and / or ISO 20653 and / or an equivalent requirement. This allows the charging system to be used outdoors in rainy weather and / or on construction sites near water-bearing equipment (e.g., water-cooled, lubricated core drilling equipment).

[0024] The housing, including the heat exchanger, may be airtight. This effectively prevents cooled / heated air from escaping to the outside. - 4 - 2025ID00021

[0025] The heat exchanger may consist of a Peltier element, a heat pipe element, and / or a compressor-based cooling system. These heat exchangers utilize reliable technologies. Peltier elements are characterized by the absence of moving parts and are therefore highly tolerant of vibrations during transport or improper handling. Heat pipes (with an internal fabric band for orientation tolerance) are passive elements that do not require energy for heat transfer. Compressor-based cooling systems offer the most design freedom.

[0026] The heat exchanger may be located in and / or on a cover of the housing. It can be assumed that the cover will be kept clear to allow access to a battery in the charging compartment, thus ensuring good heat transfer to the surroundings. As a precaution, the cover can be appropriately labeled.

[0027] The lid may be hinged to pivot, allowing it to be stored neatly after opening and freeing up a hand immediately. The lid may be removable, enabling the user to swap it between different enclosures. Alternatively, the lid may pivot on a detachable or tool-free hinge, allowing the user to flexibly choose between pivoting and detaching the lid.

[0028] It's possible that at least one charging port is located on the lid. This can offer advantages in handling, as the lid can then be used as a carrier for the battery(ies). Furthermore, more batteries can be stored within easy reach if there is a "lower layer" of ports fixed to the housing and a "upper layer" of ports fixed to the housing and lid. Additionally, this allows direct access to a battery connected to the lid when it is opened.

[0029] The heat exchanger may have a radiator outside the housing, preferably shaped to allow airflow and connected in series with a fan. The radiator improves heat transfer between the ambient air and the heat exchanger. The radiator can be protected from damage, for example, by a grille. (In- 5 - 2025ID00021)

[0030] A removable grille can make cleaning easier. The blower system can improve efficiency.

[0031] The heat exchanger unit may have a radiator inside the housing, preferably shaped to allow airflow and connected in series with a fan. The radiator improves heat transfer between the air in the charging chamber and the heat exchanger unit. The radiator can be protected from damage, for example, by a grille. A removable grille can facilitate cleaning. The fan can improve efficiency.

[0032] The charging system may contain a compartment or duct connected in series with the fan unit, housing power electronics. This allows the heat exchanger to be used to cool the electronics, thereby increasing their efficiency. Furthermore, waste heat from the power electronics can be used to heat a connected battery.

[0033] The blower may be connected in series with a vent located at the charging interface to draw air through a battery connected to the charging interface. In other words, the blower may be connected in series with a vent located at the charging interface to draw air through a battery connected to the charging interface if the vent on the other side of the interface overlaps the vent on the charging interface. This approach proposes passing cooled and / or heated air through the battery. This creates a gentle flow around the battery cells, resulting in faster and more efficient cooling / heating.

[0034] It is possible that several charging interfaces are each assigned a fan unit connected in series with their ventilation opening, with the charging system being configured to operate a fan unit depending on the coupling state of the corresponding charging interface. It is therefore proposed that the cooled / heated air is only discharged through the charging interfaces to which a battery or a suitable battery with a corresponding ventilation duct is currently coupled. This improves efficiency. A coupling may be detected electronically, and the respective fan unit controlled electronically. Alternatively, a coupling may be detected mechanically by means of a push button, and the- 6 - 2025ID00021

[0035] Each blower unit is mechanically switched on and off by means of a switch (e.g., spring-loaded). This list is not exhaustive.

[0036] The charging system may contain a control unit designed to monitor the temperature of any battery connected to the charging interface and to control the operation of the heat exchanger based on the measured temperature(s). This can be described as regulation or feedback control. It can also be referred to as actual battery temperature-based control of the heat exchanger. This ensures that excessive energy is not consumed for cooling or heating.

[0037] The charging system may include a control unit designed to detect the charging current to at least one charging interface and to control the operation of the heat exchanger based on this detected current. Using a higher charging current to charge one or more batteries often generates more heat, requiring the system to dissipate more heat. Conversely, excessively cooling batteries can hinder efficient charging. Therefore, this option also offers efficiency gains.

[0038] A condensate collection device may be located in the housing beneath the heat exchanger. In conditions of high humidity and significant temperature differences (e.g., 35°C outside temperature and 15°C inside the charging compartment), condensation can form during a workday. The condensate collection device might be designed, for example, as a plate beneath the radiator that tilts outwards when opened. This prevents condensation from reaching the charging interface.

[0039] Other possible implementations of the invention also include combinations of features or embodiments described previously or subsequently with regard to the exemplary embodiments, even if not explicitly mentioned. In such cases, a person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the invention.

[0040] Further advantageous embodiments and aspects of the invention are the subject of the dependent claims and the exemplary embodiments described below.

[0041] Invention. The invention will now be explained in more detail with reference to preferred embodiments and the accompanying figures. - 8 - 2025ID00021

[0042] BRIEF DESCRIPTION OF THE FIGURES

[0043] The following description explains the invention with reference to exemplary embodiments and figures. The figures show:

[0044] Fig. 1 schematically shows a perspective cutaway view of a charging system according to an embodiment of the invention, wherein several accumulators are located in a charging compartment of a housing; and

[0045] Fig. 2 schematically shows another perspective cutaway view of the charging system according to the embodiment of the invention.

[0046] Identical or functionally equivalent elements are indicated by the same reference symbols in the figures, unless otherwise specified. - 9 - 2025ID00021

[0047] FORMS OF EXECUTION OF THE INVENTION

[0048] Figures 1 and 2 show a charging system 100 according to an embodiment of the invention in two mutually transverse sectional views. The charging system 100 has at least one housing 102 and a heat exchanger 104. The charging system 100 may have further components.

[0049] The housing 102, for example, has a tray 106 and a lid 108. In this example, the housing 102 is double-walled, but this is optional. The inner walls 110 (side walls and bottom wall) of the double-walled tray 106, as well as an inner wall 112 (top wall) of the lid 108, together define a charging compartment 114. The charging compartment 114 is dimensioned to store at least one accumulator 116. In this case, the charging compartment 114 is dimensioned to store six accumulators 116. The accumulators 116 are each designed and dimensioned to supply energy to a mobile machine tool. The lid 108 is hinged (not shown), and the hinge can be removed to allow the lid 108 to be taken off.

[0050] The charging room 114 contains at least one charging interface 118; in this case, there are six charging interfaces 118. One charging interface 118 is designed for the mechanical and electrical coupling of a battery 116.

[0051] The lid 108 and the tray 106 together form an airtight seal for the housing 102. Specifically, the housing 102 has no unsealed openings through the outer walls 120 (side walls and bottom wall) of the tray 106 or the outer walls 122 (side walls and top wall) of the lid 108. In an operating position, the outer walls 120 of the tray 106 have an access opening 124 at the top, which is surrounded, for example, by a rubber seal (not shown) to allow for an airtight seal in conjunction with the outer walls 122 of the lid 108.

[0052] The heat exchanger 104 is arranged in the cover 108. The heat exchanger 104 has several Peltier elements 126 connected in parallel. Because it is a Peltier device, no air exchange through the cover 108 is provided. The heat exchanger 104 therefore seals the cover 108 airtight.

[0053] The heat exchanger device 104 has an outer radiator 128, which is connected to a respective outer heat transfer surface 130 of the Peltier elements 126-10-2025ID00021

[0054] is connected in a heat-transferring manner. "Outside" or "external" refers to the outer walls 120, 122 that seal the housing 102 airtight. An external fan assembly 132 is connected in series with the external radiator 128 to convey an ambient airflow through and / or along the outer radiator 128. The external fan assembly 132 is formed, for example, by two axially acting fans connected in parallel. The external radiator 128 and the external fan assembly 132 are arranged in a space 134 between an outer wall 122 of the cover 108 and a protective hood 136. The protective hood 136 has inlet openings 138 and outlet openings 140 for the inlet and outlet of ambient air.Thus, the external blower device 132 forces a directed airflow of ambient air through the inlet openings 138 into the room 134, then in the room 134 through the external radiator 128 and through the external blower device 132, and finally out of the room 134 through the outlet openings 140.

[0055] The heat exchanger unit 104 has an internal radiator 142, which is heat-transferringly connected to a respective internal heat transfer surface 144 of the Peltier elements 126. An internal fan unit 146 is connected in series with the internal radiator 142 to convey an internal airflow through and / or along the internal radiator 142. "Internal" refers to the outer walls 120, 122 that seal the housing 102 airtight.

[0056] A simple design for radiators 128 and 142 consists of stacked plates with air channels between the plates and / or comb-shaped plates. Suitable materials include aluminum, which offers a good balance between thermal conductivity and weight, and / or copper, which has excellent thermal conductivity. Radiators 128 and 142 may incorporate heat pipes. The inner radiator 142 and the outer radiator 128 may have different designs, but a uniform design is preferred.

[0057] The internal blower assembly 146 may have an axially acting fan 148 arranged in / on the cover 108. For example, the internal radiator 142 and the fan 148 are housed in a space 150 located between the outer walls 122 of the cover 108 and an inner wall 112 of the cover 108 (see Fig.

[0058] 1) is formed. From there, the air flows through a lid opening 152 into the charging chamber 114 (see Fig. 1 & 2).- 11 - 2025ID00021

[0059] Air from the charging chamber 114 enters the respective accumulator 116 through ventilation openings 154 in a base 156 (see Figs. 1 & 2) to at least partially circulate around the cells of the accumulator 116. The air exits the accumulator 116 through ventilation openings 158 (see Fig. 2). These ventilation openings 158 are part of the mating interface 160, which is complementary to the charging interface 118.

[0060] From there, the air is directed through channels 162 (i.e., ventilation openings) in the respective loading interface 118 into a flow channel 164, which is arranged between a (lateral) inner wall 110 of the tub 106 and a (lateral) outer wall 120 of the tub 106 (see Fig. 2). A further fan 166, for example an axially acting fan, may be arranged in the flow channel 164. It should be noted that Figs. 1 and 2 do not show all flow channels 164 for illustrative purposes.

[0061] Between the outer bottom wall (an outer wall 120 of the tub 105) and the inner bottom wall (an inner wall 110 of the tub 105) is a compartment 168 for power electronics 170. The power electronics 170 serve, for example, to supply power to the charging interfaces 118 and the heat exchanger unit 104, i.e., for example, the Peltier elements 126 and the blower units 132, 146, including the fans 148 and blowers 166. The flow channels 164 open into the compartment 168, so that the power electronics 170 are located in the generated airflow (see Figs. 1 & 2). From the compartment 168, other flow channels 172 lead to the cover 108 and open there into the described intermediate space 150 (see Fig. 1).

[0062] The internal blower assembly 146 has fans 148 and blowers 166. The internal blower assembly 146 may also have blowers in the charging interfaces 118. The internal blower assembly 146 may also have only some of these fans and blowers. Preferably, the blower assembly 146 ensures that each accumulator 116, which is accommodated or can be accommodated in the charging compartment 114, is subjected to flow through, around, and / or upon it. The illustrated flow path radiator 142 - charging compartment 114 - accumulators 116 - compartment 168 for power electronics 170 - radiator 142 can be traversed in this sequence or in reverse order. It is also possible that parts of it are traversed in parallel and / or not at all.

[0063] Compartment 168 also contains a control unit that controls the charging system 100, in particular the fan 166. For example, the control unit is programmed to control the fans 166 of the internal blower unit 146 depending on a 12 - 2025ID00021

[0064] The coupling state of the corresponding charging interfaces 118 is to be operated. In other words, air is only conducted through those charging interfaces 118 to which an accumulator 116 is coupled.

[0065] Although the present invention has been described with reference to exemplary embodiments, it can be modified in many ways. - 13 - 2025ID00021

[0066] REFERENCE MARK LIST

[0067] 100 charging system

[0068] 102 cases

[0069] 104 Heat exchanger unit

[0070] 106 bathtub

[0071] 108 lids

[0072] 110 Inner wall of the tub (e.g. side walls, bottom wall) 112 Inner wall of the lid (e.g. ceiling wall)

[0073] 114 Charging space

[0074] 116 Accumulator

[0075] 118 Charging interface

[0076] 120 Outer wall of the tub (e.g. side walls, bottom wall) 122 Outer wall of the lid (e.g. side walls, ceiling wall) 124 Access opening

[0077] 126 Peltier element

[0078] 128 external radiator

[0079] 130 external heat transfer surface

[0080] 132 external blower unit

[0081] Room 134

[0082] 136 Protective cover

[0083] 138 Inlet opening in protective hood

[0084] 140 Exit opening from protective hood

[0085] 142 inner radiator

[0086] 144 internal heat transfer surface

[0087] 146 internal blower unit

[0088] 148 Fan in lid

[0089] 150 mm gap in lid

[0090] 152 Cover passage

[0091] 154 Ventilation opening in the base of an accumulator- 14 - 2025ID00021

[0092] 156 Base of an accumulator

[0093] 158 Ventilation opening of a mating interface 160 Mating interface of an accumulator 162 Ventilation opening (channel)

[0094] 164 Flow channel

[0095] 166 fans

[0096] 168 compartments for power electronics

[0097] 170 Power Electronics

[0098] 172 Flow channel

Claims

- 15 - 2025ID00021 PATENT CLAIMS 1. Charging system (100) for charging at least one accumulator (116) for a mobile machine tool, in particular an accumulator (116) for a portable machine tool, comprising: a housing (102) that defines a charging space (114) in which at least one accumulator (116) can be charged at a charging interface (118), characterized by the fact that the charging system (100) has a heat exchanger device (104) which is designed to transfer heat energy between the charging chamber (114) and outside the housing (102).

2. Charging system (100) according to claim 1, wherein the housing (102), including the heat exchanger device (104), closes airtight.

3. Charging system (100) according to claim 1 or 2, wherein the heat exchanger device (104) has a Peltier device (126), a heat pipe device and / or a compressor cooling device.

4. Charging system (100) according to one of claims 1 to 3, wherein the heat exchanger device (104) is arranged in and / or on a cover (108) of the housing (102).

5. Charging system (100) according to claim 4, wherein the lid (108) is pivotable about a hinge.

6. Charging system (100) according to claim 4 or 5, wherein the lid (108) is removable.

7. Charging system (100) according to one of claims 4 to 6, wherein at least one charging interface (118) is arranged on the cover (108).

8. Charging system (100) according to one of the preceding claims, wherein the heat exchanger device (104) has a radiator (128) outside the housing (102), which is preferably shaped to allow airflow and is connected in series with a blower device (132). - 16 - 2025ID00021 9. Charging system (100) according to one of the preceding claims, wherein the heat exchanger device (104) has a radiator (142) inside the housing (102), which is preferably shaped to allow airflow and is connected in series with a blower device (146, 148, 166).

10. Charging system (100) according to claim 9, comprising a space (168) or channel connected in series with the blower device (146, 148, 166), in which a power electronics (170) is arranged.

11. Charging system (100) according to claim 9 or 10, wherein the blower device (146, 148, 166) is connected in series with a ventilation opening (162) arranged at the charging interface (118) in order to be able to convey air through an accumulator (116) coupled to the charging interface (118).

12. Charging system (100) according to claim 11, wherein several charging interfaces (118) are each assigned a blower device (146, 166) connected in series with their ventilation opening (162), wherein the charging system (100) is configured to operate a blower device (146, 166) depending on a coupling state of the corresponding charging interface (118).

13. Charging system (100) according to one of the preceding claims, comprising a control device which is configured to detect the temperature of an accumulator (116) coupled to the charging interface (118) or of each accumulator (116) coupled to one of the charging interfaces (118) and to control the operation of the heat exchanger device (104) depending on the detected temperature or temperatures.

14. Charging system (100) according to one of the preceding claims, comprising a control device which is configured to detect a charging current to the at least one charging interface (118) and to control the operation of the heat exchanger device (104) depending on the detected charging current.

15. Charging system (100) according to one of the preceding claims, wherein a condensate collection device is arranged inside below the heat exchanger device (104).

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