Battery pack with thermal conductivity element

Abstract

Battery pack, in particular power tool battery pack, with a housing (48d) in which at least one battery cell (70) is arranged, with a mechanical interface (22) via which the battery pack (18) can be mechanically connected to an external consumer (14), wherein the housing (48) is designed in multiple parts and has at least one interface housing (52d) which includes the mechanical interface (22), wherein the interface housing (52d) is essentially made of a metal or a metal alloy, where the mechanical interface (22) has increased strength, characterized by the fact that the battery pack (18d) has at least one thermal conducting element (122d) which is designed to form a thermal connection between the interface housing (52d) and a heat source (120d) arranged in the housing (48d) of the battery pack (18d), wherein the thermal conducting element (122d) is connected to the interface housing (52d) and / or the heat source (120d) by force, form and / or material connection.

Description

State of the art

[0001] A mechanical interface for connecting a battery pack to a device is known from DE 10 2015 207 730 A1. The mechanical interface is typically made of a plastic, such as fiber-reinforced polyamide or polycarbonate. The use of battery packs in increasingly powerful devices with higher energy demands is also increasing the weight of the battery packs. This increased weight places new demands on the mechanical interface of both the battery pack and the device. Further battery packs are described in DE 20 2014 100 442 U1, DE 10 2015 207 730 A1, DE 20 2014 007 259 U1, US 2016 / 0 359 151 A1, DE 10 2017 204 153 A1, and US 2007 / 0 128 505 A9. Disclosure of the invention

[0002] The invention relates to a battery pack, in particular a power tool battery pack, comprising a housing in which at least one battery cell is arranged, and a mechanical interface via which the battery pack can be mechanically connected to an external device. It is proposed that the mechanical interface have increased strength. In particular, it is proposed that the mechanical interface alternatively or additionally have increased wear resistance. Advantageously, this can extend the service life of the battery pack.

[0003] The battery pack is, in particular, part of a system consisting of the battery pack and the load, whereby the load is supplied with energy via the battery pack during operation. To establish a mechanical connection between the battery pack and the load, both the battery pack and the load each have a mechanical connection.

[0004] Interfaces that correspond to each other. Furthermore, it is also conceivable that the system includes an adapter that has at least two mechanical interfaces via which the adapter can be mechanically connected to the battery pack and the consumer.

[0005] The battery pack is electrically connected to the load via an electrical interface on the battery pack and an electrical interface on the load, which correspond to each other. Specifically, the at least one battery cell of the battery pack can be electrically connected to a drive unit of the load via the electrical interfaces of the battery pack and the load. The battery cell can be designed as a galvanic cell with a structure in which one cell terminal is located at one end and another cell terminal at the opposite end. In particular, the battery cell has a positive cell terminal at one end and a negative cell terminal at the opposite end. Preferably, the battery cells are designed as NiCd or NiMH cells, and especially preferably as lithium-based battery cells.The battery pack voltage is typically a multiple of the voltage of a single battery cell and results from the connection (parallel or series) of the battery cells. For common battery cells with a voltage of 3.6 V, this results in exemplary battery voltages of 3.6 V, 7.2 V, 10.8 V, 14.4 V, 18 V, 36 V, etc. Preferably, the battery cell is designed as a cylindrical cell, at least substantially so, with the cell terminals arranged at the ends of the cylinder. The electrical interface comprises, in particular, at least two electrical contact elements designed for energy transfer. Alternatively or additionally, the electrical interface can include a secondary charging coil element for inductive charging. Furthermore, the electrical interface can include additional contact elements designed to transmit additional information, preferably determined electronically, to the load.This could include, for example, the battery pack's state of charge, its internal temperature, a coding element, or the remaining capacity. It is conceivable that the electronics regulate or control the charging and / or discharging process of the battery pack. The electronics may, for example, include at least a circuit board, a processing unit, a transistor, a capacitor, and / or a memory element. The electronics may also include one or more sensor elements, for example, to determine the internal temperature of the battery pack. Alternatively or additionally, the electronics may include a coding element, such as a coding resistor.

[0006] The consumer can be configured, in particular, as a portable device. Preferably, the consumer is configured as a garden tool, such as a lawnmower or hedge trimmer; as a hand-held power tool, such as an angle grinder, screwdriver, drill, hammer drill, etc.; or as a measuring tool, such as a laser distance meter. Alternatively, it is also conceivable that the consumer could be configured as a radio, a lamp, or an extraction system. The battery pack interface is specifically designed for a system consisting of a battery pack and a consumer, in which the weight proportion of the battery pack is at least 1 / 8 of the total weight, preferably at least 1 / 4 of the total weight, and more preferably at least 1 / 3 of the total weight.With such weight ratios, the high weight and inertia of the battery packs can lead to very high stress on the mechanical connection if the system is dropped, potentially causing irreversible damage to the mechanical interface. The mechanical interface of the battery pack and the corresponding mechanical interface of the device are specifically designed to form a force-fit and / or form-fit connection. The connection is preferably detachable, whereby, in the context of this application, a detachable connection is understood to mean a connection that can be detached without tools and without damage. Preferably, at least one of the mechanical interfaces includes a fixing element by which the battery pack can be fixed to the device.Preferably, the fixing is releasable via an actuating element, which can be arranged on the battery pack and / or on the consumer. The actuating element can, for example, be designed as a button, lever, or push button.

[0007] In the context of this application, a mechanical interface with increased strength and / or wear resistance is understood to mean, in particular, a mechanical interface of a battery pack or a device that is reinforced by suitable design features or by the choice of material. Preferably, the mechanical interface has, at least partially, a higher tensile strength and / or yield strength than the housing of the battery pack or the housing of the device. Preferably, the average tensile strength and / or the average yield strength of the mechanical interface is greater than the average tensile strength and / or yield strength of the housing of the battery pack or the device, particularly in the area of ​​the respective mechanical interface.In this context, a yield strength is understood to be a limit beyond which a component subjected to a tensile force undergoes a transition from an elastic to a plastic region.

[0008] Furthermore, it is proposed that the mechanical interface has a contact surface, and that the ratio between the contact surface of the mechanical interface and the weight of the battery pack is less than 5 cm. 2 / kg, especially if smaller than 1 cm 2 / kg, preferably smaller than 0.5 cm 2 / kg. Alternatively, it is also conceivable that the ratio between the contact area of ​​the mechanical interface and the weight of the battery pack is in a range between 0.2 cm 2 / kg and 0.8 cm 2 / kg is preferably in a range between 0.3 cm 2 / kg, and 0.5 cm 2 / kg. In this context, the contact area refers specifically to the total contact area. This allows for the advantageous use of a mechanical interface with increased strength only in systems where it is actually required. In this context, the contact area of ​​the mechanical interface is understood to be, in particular, an area of ​​the battery pack or the device that is subjected to a force by the device or the battery pack. During normal operation of the device, the contact area is essentially oriented perpendicular to the acting force of gravity.

[0009] It is further proposed that the housing be essentially made of a housing material and that at least one reinforcing element be arranged in at least one connection area of ​​the mechanical interface. This reinforcing element is made of a material that exhibits higher strength and / or wear resistance than the housing material. Advantageously, this allows for an effective increase in the strength of the mechanical interface. In this context, "material" refers specifically to the materials from which the component is made. The battery pack housing is, in particular, at least partially made of a plastic. Preferably, the housing is made of polycarbonate or polyethylene, more preferably high-density polyethylene (HDPE). The housing is designed, at least partially, and in particular completely, as an outer casing.In this context, the term "housing material" refers in particular to the material from which the housing consists of at least 50%, preferably at least 75%, and more preferably at least 90%. In the connection area, the mechanical interface of the battery pack, when connected, is at least partially in contact with the mechanical interface of the consumer device. The contact surface is, in particular, located entirely within the connection area. Preferably, the connection area and / or the material of the reinforcing element has a higher tensile strength and / or a higher yield strength than the housing material. In particular, the reinforcing element increases the average tensile strength and / or yield strength of the housing.

[0010] Furthermore, it is proposed that the connection area of ​​the mechanical interface includes a connecting element designed to create a force-fit and / or form-fit connection between the battery pack and the consumer. The connecting element is specifically linked to the reinforcing element in such a way as to increase the strength and / or wear resistance of the connecting element.

[0011] Furthermore, it is proposed that the connecting element and / or the reinforcing element be designed such that the battery pack can be guided through the connecting element and / or the reinforcing element to create the force-fit and / or form-fit connection. The connecting element can, for example, be designed as a guide rail, in particular a linear guide rail, as a guide groove, as a guide rib, or the like.

[0012] It is further proposed that the reinforcing element be arranged partially, and in particular completely, on an outer surface of the connecting element. This measure advantageously increases both the strength and the wear resistance of the connecting element. The outer surface of the connecting element can, in particular, be designed as a guide surface along which the battery pack can be guided to create the force-fit and / or form-fit connection. Furthermore, the outer surface is designed, in particular, as the bearing surface that bears the weight of the consumer or the battery pack in the connected state.

[0013] Furthermore, it is proposed that the reinforcing element be partially or completely enclosed by the connecting element. This advantageously increases the strength of the mechanical interface, particularly of the connecting element. Specifically, the reinforcing element is positioned at a distance from the outer surface of the connecting element, thus advantageously protecting the reinforcing element from wear and / or corrosion.

[0014] Furthermore, it is proposed that each connecting element be connected to at least one reinforcing element, in particular a single reinforcing element. It is further proposed that the connecting elements be connected to a single reinforcing element. Advantageously, this can achieve a particularly effective increase in strength.

[0015] Furthermore, it is proposed that the reinforcing element be connectable to the connecting element by force-fit and / or form-fit. The connection can be detachable, in particular detachable without tools. For example, the reinforcing element could be connected to the connecting element by means of a screw connection, a clip connection, an adhesive connection, or the like. Alternatively or additionally, it is also conceivable that the reinforcing element could be connected to the connecting element by means of a connection that is not detachable or only conditionally detachable, for example by overmolding or hot riveting.

[0016] Furthermore, it is proposed that the reinforcing element be designed as an insert. This advantageously allows for cost-effective reinforcement of the mechanical interface. It is also proposed that the connecting element be manufactured by overmolding the reinforcing element.

[0017] Furthermore, it is proposed that the reinforcing element be made of a metal or a metal alloy. Alternatively or additionally, the reinforcing element can be made of a plastic different from the plastic of the housing or of a ceramic.

[0018] Furthermore, it is proposed that the housing be designed in multiple parts, with at least one interface housing comprising the mechanical interface. Advantageously, a multi-part housing can simplify the assembly of the battery pack and / or the connected device.

[0019] Furthermore, it is proposed that the interface housing be made essentially of a metal or a metal alloy. This advantageously allows for a mechanical interface with particularly high strength and / or wear resistance. The interface housing is preferably made of a non-ferrous metal. More preferably, the interface housing is made of a non-ferrous metal alloy based on aluminum, zinc, or magnesium. The non-ferrous metal alloy has an iron content not exceeding 50%.

[0020] Furthermore, it is proposed that the interface housing include at least the connecting element, which is made of a metal or a metal alloy. This advantageously allows for the creation of a mechanically robust interface in a structurally simple manner.

[0021] Furthermore, it is proposed that the interface housing partially surrounds at least one electrical contact element, which is designed for the electrical connection of at least one battery cell to the consumer, within an electrical contact area. This electrical contact element is specifically associated with the electrical interface described above. Advantageously, the interface housing protects the at least one electrical contact element.

[0022] It is further proposed that the interface housing have at least one insulating element arranged in the electrical contact area. Advantageously, the insulating element can prevent a short circuit. The insulating element is arranged, in particular, between two electrical contact elements or between the electrical contact element and the interface housing, especially an electrically conductive and / or metallic area of ​​the interface housing. The insulating element is, in particular, designed as an electrical insulator.

[0023] Furthermore, it is proposed that the insulating element be connected to the interface housing by force-fit, form-fit, and / or material-fit connection. The insulating element can be designed, for example, as an injection-molded part, an insulating film, or a coating.

[0024] Furthermore, it is proposed that the battery pack has at least one thermal interface element, which forms a thermal connection between the interface housing and a heat source located within the battery pack housing. In this context, a heat source is understood to be, in particular, a current-carrying component within the battery pack, especially in the area of ​​the battery pack's electronics, or a component heated by the current-carrying components. The heat source could be, for example, the circuit board of the electronics, an electronic component mounted on the electronics, a soldered or welded joint, electrical wires, fuses, etc. Preferably, the thermal interface element has a thermal conductivity higher than that of air. More preferably, the thermal interface element has a higher thermal conductivity than the average thermal conductivity of the housing.The thermal conducting element can, for example, be made of a thermal conducting medium, such as a thermal paste or a thermal conducting film.

[0025] Furthermore, it is proposed that the heat-conducting element be connected to the interface housing and / or the heat source by means of force-fit, form-fit, and / or material-fit connections. In particular, the heat-conducting element rests against the interface housing and the heat source.

[0026] Furthermore, the invention relates to a method for manufacturing a battery pack with a mechanical interface as described above, in which the mechanical interface is manufactured, in particular, by means of a multi-component injection molding process. In particular, at least one plastic component has increased tensile strength, and this component is used to manufacture the reinforcing element. Specifically, the interface housing is manufactured using the multi-component injection molding process.

[0027] Alternatively, the mechanical interface can be manufactured using a die-casting process or a hybrid injection molding process. Specifically, a die-casting process is used to produce an interface housing consisting primarily of a metal or metal alloy, while the hybrid injection molding process produces an interface housing consisting primarily of plastic with reinforcing elements formed as metallic inserts. Furthermore, it is proposed that the connecting element be manufactured by overmolding the reinforcing element.

[0028] Furthermore, it is proposed that the reinforcing element has at least one hole or at least one recess. Preferably, the reinforcing element has a plurality of holes or recesses which, when the reinforcing element is overmolded, lead to better adhesion or bonding of the plastic to the reinforcing element.

[0029] Furthermore, the invention relates to a consumer, in particular a hand-held power tool, with a mechanical interface as described above. The invention also relates to a system comprising a battery pack and a consumer with at least one mechanical interface, preferably one mechanical interface each, as described above. Drawings

[0030] Further advantages arise from the following description of the drawings. The drawings, the description, and the claims contain numerous features in combination. It is advantageous for those skilled in the art to also consider the features individually and combine them into meaningful further combinations. Reference numerals of features of different embodiments of the invention that are essentially identical are provided with the same number and with a letter that identifies the embodiment.

[0031] In the following exemplary embodiments, the mechanical interface according to the invention is assigned to a battery pack by way of example. Since the mechanical interface of the consumer essentially corresponds to the mechanical interface of the battery pack, it is obvious to those skilled in the art to also apply the illustrated embodiments of the mechanical interface of the battery pack to a corresponding mechanical interface of the consumer.

[0032] They show: Fig. 1 a side view of a system with a consumer and a battery pack; Fig. 2 a perspective view of a battery pack; Fig. 3 a perspective view of the battery pack according to Fig. 2 without an interface housing; Fig. 4a an exploded view of a mechanical interface according to the invention; Fig. 4b a cross-section through the mechanical interface according to Fig. 4a; Fig. 5 a cross-section through the in Fig. 1. Plane A is shown; Fig. 6 an exploded view of an alternative embodiment of the mechanical interface according to the invention; Fig. 7a an exploded view of an alternative embodiment of the mechanical interface; Fig. 7b a cross-section through the mechanical interface according to Fig. 7a; Fig. 8 a top view of a battery pack with a further alternative embodiment of the mechanical interface; Fig. 9a a cross-section through the battery pack according to Fig. 8 (through level B); Fig. 9b a longitudinal section through the battery pack according to Fig. 9a (through level C); Fig. 10 a longitudinal section of a battery pack with another alternative embodiment of the mechanical interface. Description of the exemplary implementations

[0033] In Fig. Figure 1 shows a side view of a system 10 consisting of a consumer 14 configured as a hand-held power tool 12 and a battery pack 18 configured as a hand-held power tool battery pack 16. The hand-held power tool 12 and the battery pack 18 each have a mechanical interface 20, 22, through which the two components of the system 10 are connected. The hand-held power tool 12 is configured as a rotary hammer 24 by way of example. The hand-held power tool 12 has a housing 26, at the rear end of which a handle 28 with an operating switch 30 for switching the hand-held power tool 12 on and off is arranged. At the front end of the housing 26 of the hand-held power tool 12, a tool holder 31 is arranged, which is designed to receive an insert tool 32. A drive unit 38 comprising an electric motor 34 and a gearbox 36 is arranged between the handle 28 and the tool holder 31.The gearbox 36 includes a percussion unit 40 and is located above the electric motor 34. An electronic control unit 42 is located below the electric motor 34, which allows the hand-held power tool 12 to be regulated or controlled. The battery pack 18 is located below the handle 28 and adjacent to the electronic control unit 42. The battery pack 18 and the load 14 each have a corresponding electrical interface 44, 46, via which the battery pack 18 can be electrically connected to the load 14, in particular to the electronic control unit 42 of the load 14. When connected, the battery pack 18 provides the power supply for the load 14. The battery pack 18 weighs approximately 1 / 4 of the weight of the system 10. Due to the weight and arrangement of the battery pack 18, the operation of the system 10 results in increased stress in the area of ​​the mechanical interfaces 20, 22.In order to extend the service life of the system 10, in particular the mechanical interfaces 20, 22, the mechanical interfaces 20, 22 are designed in such a way that they have increased strength.

[0034] In Fig. Figure 2 shows a perspective view of the battery pack 18 with the mechanical interface 22. The battery pack 18 is detachably mechanically connected to the load 14 via the mechanical interface 22. The battery pack 18 has a housing 48, which is exemplarily designed in multiple parts. The housing 48 is made of a plastic-containing housing material. Preferably, the housing 48 is made of polycarbonate or high-density polyethylene. The housing 48 has a base body 50 on its underside, an interface housing 52 on its top side, and two opposing side walls 54 on its side surfaces. The housing parts 50, 52, and 54 are connected to each other by fastening elements 56, which are exemplarily designed as screws. The housing parts 50, 52, and 54 are all at least partially designed as outer housing parts.A charge status indicator 58 is arranged on the front of the battery pack 18, which displays the charge status of the battery pack 18. The charge status indicator 58 is integrated into the housing 48, in particular into the base body 50. The housing 48, in particular the interface housing 52, comprises the mechanical interface 22 with a fixing element 60 and the electrical interface 46. The battery pack 18 is designed as a slide-in battery pack by way of example. When attaching the battery pack 18, connecting elements 62 of the mechanical interface 22 of the battery pack 18, which are designed as guide grooves by way of example, are connected to corresponding connecting elements 64 (see . Fig. 4) The mechanical interface 20 of the consumer 14, which is exemplified as guide rails, is engaged. The battery pack 18 is inserted into the hand-held power tool 12 by means of a relative movement in the insertion direction 66 and is guided by the connecting elements 62 of the battery pack 18 and the connecting elements 64 of the consumer. The battery pack 18 is connected to the consumer 14 in a force-fit and form-fit manner via the connecting elements 62, 64 of the two mechanical interfaces 20, 22, in a way that allows for detachable connection. The relative movement for connecting the battery pack 18 has one degree of freedom.

[0035] To lock the battery pack 18 to the load 14, the mechanical interface 22 includes the locking element 60. The locking element 60 is designed as a spring-loaded detent element that is pivotably mounted in the housing 48 of the battery pack 18. Locking is achieved by sliding the battery pack 18 along the insertion direction 66, whereby the locking element 60 engages in an undercut position at the end of the relative movement. To release the lock, the mechanical interface 22 includes an actuating element 68 designed as a push button, which is movably coupled to the locking element 60. By actuating the actuating element 68, the fixing element 60 moves into the housing 48 of the battery pack 18, and the locking mechanism between the battery pack 18 and the consumer 14 is released, so that the battery pack 18 can be released with a movement opposite to the relative movement in the insertion direction 66.

[0036] In Fig. Figure 3 shows the battery pack 18 without the interface housing 52 and without the side walls 54. The base body 50 of the housing 48 has a cell holder area. At least one battery cell 70 is accommodated in the cell holder area, and in this embodiment, the battery pack 18 has, by way of example, ten battery cells 70 connected in parallel and / or series. The battery cells 70 are arranged in two layers, with each layer comprising five battery cells 70. The battery cells 70 are cylindrical and have electrical cell terminals 72 on their end faces. The connection between the battery cells 70 is achieved via cell connectors 74. The cell connectors 74 are configured for the electrical connection of the battery cells 70 to each other in parallel and / or series. In the illustrated embodiment, two or four battery cells 70 are connected to each other via cell connectors 74.Furthermore, it can be seen that the individual battery cells 70 are spaced apart from one another in the cell holder area of ​​the base body 50 for mechanical fixation. Besides fixing the battery cells 70 in the housing 48, the cell holder area also serves to cool the battery cells 70 and is made of a thermally conductive material, for example, aluminum or a highly thermally conductive plastic. In addition, the cell holder area has sleeve-like insulating walls, so that the individual battery cells 70 are separated and electrical insulation of the individual battery cells 70 from one another can be ensured.

[0037] An electronics unit 78 is arranged above the cell holder area, particularly in the area between the base body 50 and the interface housing 52. The electronics unit 78 comprises a printed circuit board 80. The electronics unit 78 is connected to the charge status indicator 58. Electrical contact elements 82, which are provided for charging and discharging the battery pack 18, and further contact elements 84, which are designed to transmit status information, such as the charge status or temperature of the battery pack 18, to the consumer 14, are arranged on the printed circuit board 80. The electrical contact elements 82 and the further contact elements 84 are associated with the electrical interface 46. In the assembled state of the battery pack 18, the electrical contact elements 82 and 84 are located in recesses 83 (see Figure 1). Fig. 2) arranged in the housing 48, in particular in the interface housing 52. The electrical contact elements 82 are connected to the electronics 78 and to the battery cells 70. The electrical connection of the electrical contact elements 82 to the battery cells 70 is made via contact points 86 designed as solder joints, to which the battery cells 70 are soldered via the cell connectors 74 to electrical conductors 88 designed as wires. Alternatively, a welded connection of the cell connector 74 to the electrical conductor 88 is also conceivable. The solder joints 86 are arranged between the electronics 78 and the battery cells 70.

[0038] In Fig. Figure 4a shows an exploded view of the interface housing 52. The interface housing 52 is designed as part of the outer housing of the battery pack 18. The interface housing 52 encompasses the mechanical interface 22 of the battery pack, which is designed with increased strength and wear resistance. For this purpose, the interface housing 52 is positively connected to two reinforcing elements 90, which are arranged, in particular, in the connection area 92 of the mechanical interface 22. The interface housing 52 is made of the same material as the housing material of the housing 48. In particular, the interface housing 52 is made of a plastic. The reinforcing element 90 is made of sheet metal. In particular, the reinforcing element 90 is designed as a stamped and bent part.The connection area 92 is defined by the area in which the connecting elements 62 of the battery pack 18 form a force-fit and form-fit connection with the corresponding connecting elements 64 of the consumer 14. The connecting elements 62 of the battery pack 18, which are designed as guide grooves, extend essentially parallel to the insertion direction 66. To establish a force-fit connection, it is conceivable that the connecting elements have, for example, conical sections. The interface housing 52 has two connecting elements 62, each of which is connected to a single reinforcing element 90. The connection of the interface housing 52 to the reinforcing elements 90 is permanent and is created, in particular, during the manufacture of the interface housing 52.Preferably, the interface housing 52 is manufactured using a hybrid injection molding process in which the reinforcing elements 90, designed as sheet metal inserts, are placed in the injection mold for the interface housing 52 and overmolded, in particular with a plastic. Alternatively, it is also conceivable that the reinforcing element 90 is connected to the connecting element 62 by another type of connection, for example, by bonding. The reinforcing elements 90 have several recesses 94 to strengthen the connection between the interface housing 52 and the reinforcing element 90. The length of the reinforcing element 90 preferably corresponds to the length of the connecting element 62, whereby the length of the connecting element 62 is understood to mean, in particular, the length of the area of ​​the connecting element 62 in which the battery pack 18 is guided when connected to the consumer 14.Alternatively, it is also conceivable that the length of the reinforcing element 90 corresponds to at least 30% of the length of the connecting element 62, in particular at least 50% of the length of the connecting element 62, preferably at least 75% of the length of the connecting element 62. Furthermore, it is conceivable that more than one reinforcing element 90 is connected to and reinforces a connecting element 62.

[0039] In Fig. Figure 4b shows a section through a perspective view of the interface housing 52 connected to the reinforcing elements 90. The reinforcing element 90 is connected to the mechanical interface 22 or the interface housing 52 such that the reinforcing element 90 is partially or partially enclosed on one side by the interface housing 52. The cross-sectional profile of the reinforcing element 90 can assume various shapes, such as L-shaped, U-shaped, T-shaped, double T-shaped, or a combination of these shapes. In particular, the reinforcing element 90 is arranged such that it forms an outer surface 96 of the connecting element 62. Preferably, the reinforcing element 90 is made of a corrosion-resistant metal or a corrosion-resistant metal alloy.The reinforcing element 90 is preferably designed as a bearing surface 98 of the connecting element 62, which, in the connected state, rests against the corresponding connecting element 64 of the consumer 14 and is subjected to a weight force emanating from the weight of the battery pack 18. The interface housing 52 is connected to the other housing parts 54 of the housing 48 of the battery pack 18 via the fastening elements 56, which are designed as screws. For this purpose, the interface housing 52 has fastening element receptacles 100 (see figure). Fig. 4a), which are exemplified as screw bosses. To further increase the strength of the mechanical interface 22, the reinforcing element 90 also has at least one fastening element receptacle 102 (see Fig. 4a) which, in the connected state, is arranged so adjacent to the fastening element receptacles 100 of the interface housing 52 that the fastening element 56 is received by both fastening element receptacles 100, 102. Advantageously, the force acting on the bearing surfaces 98 is thus also absorbed by at least one or two of the fastening elements 56.

[0040] In Fig. 5 is a cross-section through the mechanical interface 20 of the consumer 14 and the mechanical interface 22 of the battery pack 18 of the system 10 according to Fig. Figure 1 shows that the consumer 14 has an electrical interface 44 comprising several electrical contacts 104, through which the electrical interface 44 of the consumer 14 can be electrically connected to the electrical interface 46 of the battery pack 18. The electrical contacts 104 are arranged on a contact holder 105, which is attached in the handle 28 of the consumer 14, in particular in the base of the handle 28 of the consumer 14.

[0041] In this embodiment, the connecting element 64 of the consumer 14, designed as a guide rail, engages in the corresponding connecting element 62 of the battery pack 18, which is designed as a guide groove. In this embodiment, only the mechanical interface 22 of the battery pack 18 is reinforced by means of reinforcing elements 90. Alternatively or additionally, however, it is also conceivable that the mechanical interface 20 of the consumer 14 is designed with reinforcing elements. The connecting element 64 rests against three outer surfaces of the connecting element 62 of the battery pack 18, with two of the three outer surfaces of the connecting element 62 being formed from the reinforcing element 90. During normal operation of the hand-held power tool 12, the orientation of the system 10 essentially corresponds to that shown in Fig. In the orientation shown in Figure 1, the battery pack 18 is arranged at the lower end of the hand-held power tool 12. In this orientation, as previously described, a force emanating from the weight of the battery pack 18 acts on the contact surface 98 of the connecting element 62.

[0042] In Fig. Figure 6 shows an alternative embodiment of the mechanical interface 22a with an alternative reinforcing element 90a. The mechanical interface 22a comprises a single reinforcing element 90a, which is connected to the interface housing 52a such that all connecting elements 62a of the mechanical interface 22a are reinforced by the single reinforcing element 90a. The reinforcing element 90a consists of two sub-sections 106a, which essentially correspond to the reinforcing elements 90 of the previous embodiment, wherein the two sub-sections 106a are connected to each other by cross braces 108a. Advantageously, this further increases the strength of the mechanical interface 22a.

[0043] In Fig. Figure 7a shows a further alternative embodiment of the mechanical interface 22b with an alternative reinforcing element 90b. The interface housing 52b is, as previously described, made of a plastic and comprises two connecting elements 62b. The connecting elements 62b are, as previously described, each connected to a reinforcing element 90b, in particular by a hybrid injection molding process. The reinforcing elements 90b are designed as sheet metal inserts and extend along the longitudinal extent of the connecting elements 62b. The reinforcing elements 90b have a plurality of holes 94 through which the connection of the reinforcing element 90b with the connecting element 62b can be reinforced by the interface housing 52b or the connecting element 62b with the reinforcing element 90b interlocking during the manufacturing process.Furthermore, the reinforcement elements 90b each have three fastening element receptacles 102b.

[0044] In Fig. Figure 7b shows a section through the mechanical interface 22b. In contrast to the embodiment of the mechanical interface 22 according to Fig. 4. The reinforcing element 90b does not form the outer surface 96b of the connecting element 62b. As can be seen in the cross-section, the reinforcing element 90b is substantially completely enclosed by the interface housing 52b or the connecting element 62b in the connection area. Preferably, the reinforcing element 90b is enclosed by the interface housing 52b in such a way that the reinforcing element 90b is shielded from moisture by the interface housing 52b and thus no external moisture can come into contact with the reinforcing element 90b. Advantageously, this allows a non-corrosion-resistant metal or a non-corrosion-resistant metal alloy to be used for the manufacture of the reinforcing element 90b.

[0045] In Fig. Figure 8 shows a further alternative embodiment of the battery pack 18c with a mechanical interface 22c in a top view. The structure of the battery pack 18c essentially corresponds to the structure of the battery pack 18 according to Figure 8. Fig. 2 and Fig. 3, however, differs essentially in the mechanical interface 22c, which has a metallic interface housing 52c. In this embodiment, the housing 48c of the battery pack 18c is predominantly made of plastic or a plastic-containing material. "Predominantly" in this context means, in particular, that at least 50%, preferably at least 75%, of the outer surface of the housing is made of plastic or a plastic-containing material. In particular, the base body 50c and the side walls 54c are made of a plastic-containing material. The interface housing 52c is, by way of example, made of aluminum. Alternatively, however, other metals or metal alloys, in particular non-metals, are also suitable. The interface housing 52c includes connecting elements 62c, which, as already described, are designed for a force-fit and / or form-fit connection with a consumer 14.The connecting elements 62c are integrally formed with the interface housing 52c and are specifically designed as guide grooves. The outer surfaces 96c of the connecting elements 62c are partially designed as guide surfaces along which the battery pack 18c is guided when connected to the load 14. The outer surfaces 96c of the connecting elements 62c are preferably machined to reduce wear in the area of ​​the guide surfaces. For example, the outer surfaces 96c can be machined by milling, grinding, polishing, etc. Due to the metallic mechanical interface 22c, the battery pack exhibits a tensile strength or yield strength in the area of ​​the mechanical interface 22c, particularly in the area of ​​the connecting elements 62c, that is higher than the average tensile strength or yield strength of the housing 48c.

[0046] In Fig. 9a is a section through the in Fig. Figure 8 shows plane B. Plane B extends through the interface housing 52c and the electrical contact elements 82c, 84c arranged in recesses 83c of the interface housing 52c. The area in which the electrical contact elements 82c, 84c are arranged, in particular the area spanned by the recess 83c, forms an electrical contact area 112c in which the electrical contact element 82c or the further electrical contact element 84c can be electrically connected to the corresponding electrical interface 44 of the consumer 14. In particular, the electrical contact elements 82c, 84c are each arranged between two lateral walls 110c of the interface housing 52, which spatially delimit the electrical contact area 112c. The electrical contact elements 82c, 84c are designed as spring contacts by way of example.To ensure that no electrical contact is established between the electrical contact elements 82c, 84c and the electrically conductive interface housing 52c, the battery pack 18c has insulating elements 114c. The insulating elements 114c are preferably connected to the interface housing 52c via a force-fit and / or form-fit connection or via a material-fit connection. The insulating elements 114c are, in particular, positioned between an electrical contact element 82c, 84c or another current-carrying element, for example an electronic component 81c (see Figure 1). Fig. 9b) of the electronics 78c of the battery pack 18c, arranged so that the interface housing 52c cannot be energized, thereby advantageously preventing short circuits in a metallic interface housing 52c. The insulating elements 114c can, for example, be designed as an insulating film 116c. The insulating elements 114c designed as an insulating film 116c can, for example, be bonded to the side walls 112c surrounding the electrical contact elements 82c, 84 by means of an adhesive bond. The circuit board 80c is arranged below the electrical contact elements 82c, 84c, and the interface housing 52c is arranged above the electrical contact elements 82c, 84c. In particular, an additional insulating element 114c, designed, for example, as an insulating insert 118c (see Fig. 9b). The insulating insert can be formed as an injection-molded part and attached to the inner surface of the interface housing 52c by means of a clip connection. Alternatively, it is also conceivable that the entire inner surface of the interface housing 52c is coated with an electrically insulating plastic coating.

[0047] In Fig.Figure 10 shows a further alternative embodiment of the battery pack 18d with a mechanical interface 22d. Analogous to the previous embodiment, the mechanical interface 22d is made of metal. The battery pack 18d is shown in a longitudinal section. An insulating element 114d is arranged on the inner surface of the interface housing 52d above the electronics 78d, in particular above the circuit board 80d. Heat sources 120d are arranged inside the battery pack 18d, in particular on the circuit board 80d, which heat up during charging or discharging of the battery pack 18d. The heat sources 120d can be designed as current-carrying elements or as a component that heats up via a current-carrying element.For efficient cooling, the battery pack 18d has thermal conductivity elements 122d designed to thermally connect the heat sources 120d to the metallic interface housing 52d, thereby advantageously enabling efficient heat transfer from the interior of the housing 48d of the battery pack 18d. The thermal conductivity element 122d is exemplified as a thermally conductive film with double-sided adhesive for easy mounting. The thermal conductivity elements 122d are in contact with both the heat sources 120d and the interface housing 52d, preferably directly. The size of the thermal conductivity elements 122d is preferably adapted substantially to the size of the heat sources 120d to be cooled. Advantageously, the insulating element 114d has recesses in which the thermal conductivity elements 122d are arranged and through which the thermal conductivity elements 122d can be thermally connected to the interface housing 52d.The heat conducting elements 122d are designed to be electrically insulating.

Claims

[1] Battery pack, in particular a hand tool battery pack, with a housing (48d) in which at least one battery cell (70) is arranged, with a mechanical interface (22) via which the battery pack (18) can be mechanically connected to an external consumer (14), wherein the housing (48) is designed in multiple parts and has at least one interface housing (52d) which includes the mechanical interface (22), wherein the interface housing (52d) is essentially made of a metal or a metal alloy, where the mechanical interface (22) has increased strength, characterized by , that the battery pack (18d) has at least one thermal conducting element (122d) which is designed to form a thermal connection between the interface housing (52d) and a heat source (120d) arranged in the housing (48d) of the battery pack (18d), wherein the thermal conducting element (122d) is connected to the interface housing (52d) and / or the heat source (120d) by force, form and / or material connection. [2] Battery pack according to claim 1, characterized by , that the mechanical interface (22) has a contact area (98), and a ratio between the contact area (98) of the mechanical interface (22) and a weight of the battery pack (18) is less than 5 cm 2 / kg. [3] Battery pack according to any one of the preceding claims, characterized by , that the interface housing (52c) has at least one connecting element (62c) which is designed to form a force-fit and / or form-fit connection of the battery pack (18) with the consumer (14). [4] Battery pack according to claim 3, characterized by , that the connecting element (62c) is made of a metal or a metal alloy. [5] Battery pack according to any one of the preceding claims, characterized by , that the interface housing (52c) partially surrounds an electrical contact element (82c, 84c) which is designed for the electrical connection of at least one battery cell (70c) to the consumer (14) in an electrical contact area (112c). [6] Battery pack according to claim 5, characterized by that the interface housing (52c) has at least one insulating element (114c) which is arranged in particular in the electrical contact area (112c). [7] Battery pack according to claim 6, characterized by , that the insulating element (114c) is connected to the interface housing (52c) by force, form and / or material connection. [8] Battery pack according to one of claims 6 to 7, characterized by, that the insulating element (114c) is designed as an injection-molded part, as an insulating film or as a coating. [9] Method for manufacturing a battery pack according to one of the preceding claims, wherein the mechanical interface (22) is manufactured by means of a multi-component injection molding process or by means of a die casting process. [10] Consumer, in particular hand-held power tool, for connection to a battery pack with a mechanical interface (22c; 22d) according to any one of claims 1 to 8. [11] System comprising a battery pack (18c; 18d) and a consumer (14) with a mechanical interface (22c; 22d) according to one of the preceding claims.

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