Energy storage unit for an electrical consumer

Abstract

The invention relates to an energy storage unit (12) for an electrical consumer (20), having a plurality (N) of energy storage cells (50), wherein each energy storage cell (50) has two electrical cell poles (54) and the electrical cell poles (54) of at least two energy storage cells (50) are connected in an electrically conductive manner to one another in series or in parallel as a cell cluster (48) by means of at least one cell connector (56). It is proposed that the energy storage unit (12) has at least two cell clusters (48) which are connected to one another by means of an insulating plate (66) produced in a two-component or three-component injection moulding method. The invention also relates to an electrical consumer (30) having the energy storage unit (12) according to the invention and to a system consisting of an electrical consumer (30) designed as a hand-held machine tool (24, 26, 28) and at least one energy storage unit (12) according to the invention designed as an exchangable rechargable battery pack (10).

Description

[0001] Description

[0002] title

[0003] Energy storage unit for an electrical consumer

[0004] Description

[0005] The invention relates to an energy storage unit for an electrical consumer according to the preamble of the independent claim.

[0006] State of the art

[0007] A large number of electrical consumers are operated with energy storage units (also known as rechargeable batteries, battery packs, or interchangeable battery packs) that can be replaced by the operator without tools. These units are discharged by the electrical consumer and recharged using a charger. To achieve the desired IP (Ingress Protection) rating, the energy storage units have a suitably sealed housing (e.g., for IP58). Typically, the energy storage units consist of a plurality of energy storage cells connected in series and / or parallel to achieve the required battery voltage or capacity. If the energy storage cells are designed as lithium-ion (Li-ion) cells, for example, a high power and energy density can be achieved with particular advantage.

[0008] The electrical cell poles of at least two energy storage cells of the energy storage unit can be electrically connected to one another via at least one cell connector in a series or parallel circuit as a so-called cell cluster or submodule. Such cell clusters allow for easier assembly and scaling of the energy storage units. The electrical connection of the cell connectors to the electrical cell poles is achieved by means of a material-to-material connection, for example by soldering, cold welding, or the like. The cell connectors are often designed as flat stamped sheets or tabs, which in turn are electrically connected to a printed circuit board (PCB) of the energy storage unit for monitoring the energy storage cells via electrical connection points on the circuit board.

[0009] To transfer energy between the energy storage unit and the electrical consumer or charger, corresponding power supply contacts of an electromechanical interface are used. These contacts are electrically connected to the circuit board and / or the cell connectors via rigid busbars, stamped grids, etc., or via flexible cables, ribbon cables, etc. Due to their flexibility and oscillation capability, cables and ribbon cables can better decouple mechanical influences such as vibrations and shocks, particularly at their electrical connection points, but they often have a limited current-carrying capacity. Thanks to their flat design, busbars and stamped grids enable a compact design of the energy storage unit while maintaining a high current-carrying capacity and are particularly used when punching and bending processes are necessary for shaping and for a special connection geometry.However, at higher currents they require thicker cross-sections, which result in low flexibility, so that under corresponding mechanical influences there is a risk that the welding points or soldering joints will come loose.

[0010] The object of the invention is to provide a high-performance energy storage unit which, compared to the prior art, has the most compact design possible and is also cost-effective to manufacture.

[0011] Advantages of the invention

[0012] The invention relates to an energy storage unit for an electrical consumer, comprising a plurality of energy storage cells, wherein each energy storage cell has two electrical cell poles and the electrical cell poles of at least two energy storage cells are electrically connected to one another in a series or parallel circuit as a cell cluster via at least one cell connector. To achieve the above object, it is provided that the energy storage unit has at least two cell clusters which are connected to one another by means of an insulating plate produced in a two-component (2K) or three-component (3K) injection molding process. In a particularly advantageous manner, this makes it possible to dispense with additional assembly devices which hold the individual cell clusters in position during assembly of the energy storage unit.Thus, the cell clusters and the insulating plate connecting them form a structural unit that can be used for subsequent assembly steps of the energy storage unit. This significantly simplifies and reduces the cost of energy storage unit assembly by eliminating additional connecting elements such as screws, adhesives, or similar. Furthermore, such a structural unit provides additional mechanical stabilization of the cell clusters against vibrations, shocks, and impacts, or similar, during use of the energy storage unit. Particularly advantageously, an outer contour of the insulating plate essentially corresponds to an envelope of the cell clusters in cross-section through a longitudinal axis of the structural unit.

[0013] Furthermore, the invention relates to an electrical consumer with an energy storage unit according to the invention and to a system consisting of an electrical consumer designed as a handheld power tool and at least one energy storage unit designed as a removable battery pack. However, an electrical consumer in the context of the invention should fundamentally be understood to mean all devices with an electrical load that can be supplied by means of an energy storage unit. The electrical load can be a predominantly inductive load in the form of an electric motor drive. Predominantly resistive or capacitive loads are also conceivable. Suitable electric motor drives are, in particular, electrically commutated electric motors (so-called EC or BLDC motors), whose individual phases are controlled via at least one power transistor by pulse width modulation to control or regulate their speed and / or torque.In this context, the invention is applicable to battery-operated machine tools for machining workpieces using an electrically powered tool. The electrical processing device can be designed both as a portable handheld power tool and as a stationary power tool. Typical machine tools in this context are handheld or pillar drills, screwdrivers, impact drills, planers, angle grinders, orbital sanders, cell polishing machines, or the like. Other electrical loads include garden and construction equipment such as lawn mowers, grass trimmers, pruning saws, power cutters and trenchers, blowers, robot breakers and excavators, or the like, as well as measuring devices such as laser rangefinders, wall scanners, etc. Furthermore, the invention is applicable to household appliances such as vacuum cleaners, mixers, etc., and electrically powered road and rail vehicles such as e-bikes, e-scooters, pedelecs, electric and hybrid vehicles, etc., as well as aircraft and ships with an energy storage unit according to the invention.

[0014] The voltage class of the energy storage unit results from the connection (parallel or series) of the individual energy storage cells integrated in the energy storage unit and is generally an integer multiple (>= 1) of the voltage of the individual energy storage cells. An energy storage cell is typically designed as a galvanic cell with a structure in which one cell pole is located at one end and another cell pole at an opposite end. In particular, the energy storage cell has a positive cell pole at one end and a negative cell pole at an opposite end. The energy storage cells are preferably designed as lithium-based battery cells, e.g. Li-ion, Li-cell polymer, Li-metal or the like. However, the invention is also applicable to energy storage units with Ni-Cd, Ni-Mh cells or other suitable cell types.For common Li-ion energy storage cells with a cell voltage of 3.6 V, voltage classes of 3.6 V, 7.2 V, 10.8 V, 14.4 V, 18 V, 38 V, etc. are obtained, for example. An energy storage cell is preferably designed as an at least substantially cylindrical round cell, with the cell poles arranged at the ends of the cylinder. However, the invention is not dependent on the type and design of the energy storage cells used, but can be applied to any energy storage units and cells, e.g., in addition to round cells, also prismatic cells, pouch cells or the like. The DC voltage values ​​are primarily based on the typical cell voltages of the energy storage cells used. For example, for pouch cells and / or cells with a different electrochemical composition, voltage values ​​are possible that differ from those of energy storage units equipped with Li-ion cells.If the energy storage unit is designed as a removable battery pack, it can be detachably connected via the electromechanical interface of the removable battery pack to a correspondingly complementary electromechanical interface of the electrical consumer or charger in a force-locking and / or positive-locking manner. A "detachable connection" is to be understood in particular as a connection that can be released and established without tools - i.e., by hand. The design of the electromechanical interfaces and their receptacles for the force-locking and / or positive-locking detachable connection are not the subject of this invention. A person skilled in the art will select a suitable embodiment for the electromechanical interface depending on the power or voltage class of an electrical consumer and / or removable battery pack, so this will not be discussed in further detail here. The embodiments shown in the drawings are therefore to be understood only as examples.In particular, interfaces with more electrical contacts than those shown can be used.

[0015] In a further development of the invention, it is provided that a first of the at least two components of the insulating plate is designed as a hard component and a second of the at least two components is designed as a soft component. The hard component essentially serves to stiffen the insulating plate, while the soft component functions as mechanical damping or fixing and tolerance compensation. The soft component has a hardness of 0 to 100 Shore A, preferably 30 to 70 Shore A. In addition, the soft component can be used to seal dedicated areas of the energy storage unit or the cell cluster, for example in the form of a sealing lip. In the case of a three-component injection molding process (3K), a third component of the insulating plate can be designed as a hard or soft component with different material properties than the first and second components.For example, a harder or softer TPE or even metal inserts for the insulation plate could be considered in order to adapt the insulation plate to specific requirements for the energy storage unit with regard to its impact and vibration resistance and / or its tightness. The hard component has a plurality of locking hooks for attachment to the at least two cell clusters. Instead of the locking hooks, tabs, mushroom heads or corresponding projections and / or recesses, for example in the form of a tongue and groove principle, can alternatively be used for mounting on the cell clusters. In this way, on the one hand, good mechanical stabilization and, on the other hand, very simple and quick assembly of the structural units consisting of the cell clusters and the insulation plate can be achieved. In addition, in the event of damage to one of the cell clusters or individual energy storage cells, disassembly and simplified replacement are possible.

[0016] A further embodiment provides for the locking hooks and / or a plurality of mechanical guides to be arranged on the insulating plate in such a way that the cell clusters can only be connected to the insulating plate using a poka-yoke principle. This allows for increased process reliability during assembly, preventing any assembly errors that could potentially lead to damage to the cell clusters or energy storage cells.

[0017] The soft component is preferably formed as a plurality of elastic lamellae and / or domes arranged within the hard component and connected to one another, in particular via webs of the same material. The plurality of lamellae and / or domes preferably corresponds to the number of energy storage cells of at least one of the cell clusters connected to the insulating plate. In this way, the individual energy storage cells or their cell poles and / or the cell connectors connecting them can be effectively protected from mechanical vibrations, shocks, impacts, or the like during use of the energy storage unit.

[0018] Furthermore, it is intended that the lamellae and / or domes are circular in shape and their position corresponds to the electrical cell poles of the cell clusters connected to the insulating plate. The circular lamellae or domes have the advantage that they can be easily pressed together, thus stabilizing the assembly. Furthermore, they can perform an additional sealing function within the structural unit or energy storage unit. In order to hold the energy storage cells and / or cell connectors in position and to further improve the robustness of the energy storage unit, the lamellae and / or domes are pressed together when the insulating plate is installed. In addition, this allows the heat generated during operation of the electrical consumer or during charging of the energy storage unit to be dissipated or distributed.

[0019] A further object of the invention may be to provide a high-performance energy storage unit which, compared to the prior art, has the most compact design possible and is also cost-effective to manufacture.

[0020] The invention relates to an energy storage unit for an electrical consumer, comprising an electromechanical interface for connecting the energy storage unit to the electrical consumer, comprising a plurality of energy storage cells, wherein each energy storage cell has two electrical cell poles and the electrical cell poles of at least two energy storage cells are electrically connected to one another in a series or parallel circuit as a cell cluster via at least one cell connector, and comprising a printed circuit board which electrically connects the at least one cell connector of the cell cluster to a power supply contact of the electromechanical interface, wherein the power supply contact is electrically connected to a busbar or is designed as a busbar. To achieve the further object, it is provided that the busbar is arranged directly on a surface of the printed circuit board.This is particularly advantageous because the circuit board manufacturer can install the busbar at low cost, thereby improving the robustness of the design. Rigid busbars, particularly those with larger cross-sections, can also be installed much more easily and reduce the load on the connection points. Furthermore, it is possible to design the power supply contacts as busbars even in a rigid design. By omitting hybrid components (e.g. a busbar with a copper mesh conductor), further manufacturing costs can be saved. In a further development of the invention, the circuit board has at least one recess for the busbar, into which at least one section of the busbar is inserted.This allows strain and / or shock relief for the busbar to be accommodated very efficiently and easily within the installation space of the circuit board, enabling a particularly compact design of the energy storage unit. Furthermore, greater mobility of the busbar is achieved. If a force is introduced into the connection point of the busbar, which is designed as a welding or soldering point - for example, caused by an impact on the energy storage unit or the electrical load - the busbar can deform elastically in the area of ​​at least one recess in the circuit board in order to dissipate the introduced force as deformation energy. This relieves the load on both the connection points on the circuit board and on the busbar.Immersion should be understood, in particular, as meaning that the corresponding section of the busbar penetrates into the at least one recess below the surface of the circuit board with a first end and protrudes from the at least one recess or another recess above the surface with a second end. The corresponding section of the busbar is therefore located at least partially, in particular completely, below the surface of the circuit board.

[0021] It is particularly advantageous if the at least one section of the busbar is inserted into the circuit board in such a way that it protrudes from the surface on the opposite side of the circuit board. This makes it possible to increase the spring effect of the busbar and thus the protection of the electrical connection points or to adapt it to any specifications. In this context, it is advisable if the at least one section is wave-shaped, in particular U-, V-, W- or meander-shaped. In addition, the at least one section of the busbar can be made of a different, electrically conductive material than the busbar. Additionally or alternatively, it can be provided that the at least one section of the busbar has a cross-section and / or a thickness that deviates from the cross-section and / or thickness of the busbar.Furthermore, it can be provided that the at least one section of the busbar has a depth extension that is at least as large as its length along the busbar. A further object of the invention can be to provide a high-performance energy storage unit that, compared to the prior art, has a design that is as compact as possible and protected from environmental influences, in particular dirt, liquids, or the like, and is also cost-effective to manufacture.

[0022] The invention relates to an energy storage unit for an electrical consumer, with an electromechanical interface for connecting the energy storage unit to the electrical consumer, with a plurality of energy storage cells, wherein each energy storage cell has two electrical cell poles and the electrical cell poles of at least two energy storage cells are electrically connected to one another in a series or parallel circuit as a cell cluster via at least one cell connector, and with a printed circuit board which electrically connects the at least one cell connector of the cell cluster to a power supply contact of the electromechanical interface, wherein the power supply contact is electrically connected to a busbar or is designed as a busbar.

[0023] To achieve the further object, it is provided that a sub-housing of the energy storage unit is formed from an electrically non-conductive material which is open at least on one end face and surrounds the cell cluster with its remaining sides, and that the busbar is overmolded with the electrically non-conductive material on at least one side of the sub-housing. This particularly advantageously results in a compact and robust design while simultaneously protecting the energy storage unit from external influences. By overmolding the busbars, the area around them is sealed accordingly and prevents liquid and dirt from entering the interior of the energy storage unit. This also provides increased protection for sensitive components of the energy storage unit, such as the electronics or the energy storage cells, through appropriate insulation from the environment.A sub-housing is understood, in particular, to be a housing that is at least partially surrounded by another outer housing and is therefore not entirely accessible from the outside. The sub-housing thus forms a separate or separable sub-housing from the outer housing, which is partially or completely surrounded by the outer housing and is not connected to it by a material fit, but rather only by a force-fitting and / or positive fit.

[0024] In a further development, it is provided that the electrically non-conductive material of the sub-housing is additionally thermally conductive. This enables increased heat spreading or dissipation and thus improved cooling in the contact area by directly coupling the busbars to an outer housing of the energy storage unit and / or the electrical consumer.

[0025] The sub-housing has a recess through which the busbar is electrically connected to the power supply contact or a signal or data contact, or through which the busbar is configured as a power supply contact or a signal or data contact. This reduces assembly effort and susceptibility to errors, resulting in a corresponding improvement in quality. To enable welding of the power supply contact, signal or data contact, or the tulip-shaped contact, the busbar is accessible from both sides at the corresponding contact point.

[0026] The outer housing of the energy storage unit has at least one removable end cap, whereby the end cap and the at least one open end face of the sub-housing are sealed by a sealing lip when installed. The end cap enables easy maintenance or repair of the energy storage unit because defective components can be replaced by removing the end cap. Furthermore, the sealing lip, in conjunction with the replaceable end cap, ensures a high level of protection against environmental influences.

[0027] The sealing lip engages in a groove surrounding at least one open end face of the sub-housing and / or the end cap. Thus, when the end cap is mounted, for example, when screwing it onto the outer housing of the energy storage unit, the sealing lip is pressed into the groove of the sub-housing, sealing the area accordingly. In a further embodiment of the invention, the sub-housing has a pressure equalization opening on one side, through which pressure equalization between the sealed sub-housing and the environment can particularly advantageously take place. This prevents damage to the sensitive components of the energy storage unit, such as the electronics or the energy storage cells, due to any unfavorable pressure conditions inside the sub-housing compared to the environment.

[0028] The pressure equalization opening is sealed by a pressure equalization membrane. This allows gas and moisture exchange between the energy storage unit's sub-housing and the environment, while the special material properties of the pressure equalization membrane prevent water and dirt from entering the energy storage unit.

[0029] A further object of the invention may be to provide a high-performance energy storage unit which, compared to the prior art, has a design which is as compact as possible and protected from environmental influences, in particular dirt, liquids or the like, and which is also cost-effective to manufacture.

[0030] The invention relates to an energy storage unit for an electrical consumer, comprising an outer housing which serves to accommodate a plurality of energy storage cells, wherein the outer housing has an electromechanical interface on a first side wall or a top side for a tool-free detachable connection to an electromechanical interface of the electrical consumer. To achieve the further object, it is provided that a housing part consisting of at least three different injection-molded components is arranged on or in the outer housing. The housing part is accordingly manufactured using a three-component injection-molding process. With particular advantage, the variety of individual components of the energy storage unit can be reduced compared to a housing part manufactured using a two-component injection-molding process by corresponding functional integration into existing components using an additional injection-molded component.On the one hand, this helps to reduce manufacturing costs and, on the other hand, to improve the quality of the energy storage unit due to reduced assembly effort and a resulting reduced susceptibility to errors.

[0031] In a further development of the invention, it is provided that the at least three injection-molded components of the housing part are formed by a hard component, a soft component and at least one third injection-molded component, wherein the third injection-molded component differs from the hard component and the soft component in its material properties. The hard component can be made of a thermoplastic, for example PC / ABS or PA / GF, and the soft component can be made of a thermoplastic elastomer (TPE). The hard component thus essentially serves to stiffen and shock-resistant the energy storage unit, while the soft component in conjunction with the hard component enables improved handling of the energy storage unit as well as mechanical damping or fixing, improved sealing and / or tolerance compensation of the energy storage cells or cell clusters.The soft component has a hardness of 0 to 100 Shore A, preferably 30 to 70 Shore A. A third injection-molded component could be, for example, a harder or softer TPE, but also a metal insert or a hard plastic, in order to adapt the energy storage unit or its energy storage cells to specific requirements regarding impact and vibration resistance, tightness, and / or operability.

[0032] The housing part can be designed as an end cap that can be detachably fastened to an end face of the outer housing of the energy storage unit or the electrical consumer. A base body of the end cap is formed from the hard component, and at least a first side of the end cap is overmolded, in particular almost completely, with the soft component. This results in improved handling for an operator, for example in that there is more grip, especially with wet hands. In addition, the overmolded soft component of the hard component increases robustness against impacts, for example if the energy storage unit or the electrical consumer is dropped. Additionally or alternatively, the soft component forms a sealing lip on a second side of the end cap that is injected into a groove in the hard component.of the electrical consumer against moisture, liquids, dust and other forms of dirt, and on the other hand makes mounting the end cap much easier, as the sealing lip does not have to be inserted separately into the groove.

[0033] Furthermore, the soft component forms a plurality of damping elements on a second side of the end cap, which are molded onto projections of the hard component. These damping elements serve to provide axial and / or radial damping of the energy storage cells. This makes the energy storage unit more robust against any shocks, impacts, and vibrations that may occur when working with the electrical device. Furthermore, the damping elements serve to better secure the energy storage cells or cell clusters within the energy storage unit.

[0034] The usability of the energy storage unit can be increased by the third injection-molded component being a further soft component made of a transparent or translucent, in particular thermoplastic, elastomer. Thus, the third injection-molded component can serve, for example, as a charge level indicator for the energy storage unit, wherein the light from individual LEDs mounted on a circuit board of the energy storage unit is guided outwards by the third injection-molded component designed as a light guide. For this purpose, the third injection-molded component is injected into a recess in the hard component, which is preferably not overmolded by the soft component. This particularly advantageously increases the robustness of the energy storage unit through additional sealing in the area of ​​the charge level indicator.

[0035] The operability of the energy storage unit can be improved while maintaining a high level of robustness by injecting at least one actuating element and / or at least one optical separating element into the third injection-molded component, which is formed in particular from the hard component or a comparable thermoplastic. Thus, for example, the charge level indicator can be activated for a defined time window by briefly pressing the actuating element. Starting a rapid charging process or the like would also be conceivable. By means of the at least one optical separating element, it is possible to distinguish different charge levels of the energy storage unit more clearly from one another because this can prevent stray light between the individual LEDs indicating the charge levels.

[0036] Examples of implementation

[0037] drawing

[0038] The invention is explained below by way of example with reference to Figures 1 to 10, wherein the same reference numerals in the figures indicate the same components with the same mode of operation.

[0039] They show:

[0040] Fig. 1 : a system consisting of at least one electrical energy storage device designed as a removable battery pack and at least one electrical device connectable to the removable battery pack for charging or discharging the removable battery pack in a schematic representation,

[0041] Fig. 2: a perspective view of the interior of the removable battery pack in a reassembled state,

[0042] Fig. 3: a perspective view of a structural unit consisting of two cell clusters according to Figure 2 in a disassembled state,

[0043] Fig. 4: a perspective view of an insulating plate of the cell

[0044] Clusters according to Figure 3 formed housing part of the interchangeable battery pack in a first embodiment (Figure 4a) and in a second embodiment as a detail enlargement (Figure 4b),

[0045] Fig. 5: a section through the assembled unit according to

[0046] Figure 3 along a longitudinal axis of the assembly,

[0047] Fig. 6: a perspective view of the assembled interior of the interchangeable battery pack according to Figure 2,

[0048] Fig. 7: a section along the longitudinal axis through the fully assembled removable battery pack (Figure 7a) and an enlarged detail of a sealing lip for sealing the removable battery pack (Figure 7b),

[0049] Fig. 8: a section along the longitudinal axis to illustrate pressure equalization of the removable battery pack or the sub-housing,

[0050] Fig. 9: a perspective view of a circuit board of the removable battery pack with busbars arranged on it,

[0051] Fig. 10: a busbar of the removable battery pack in a side view in an undeformed and in a deformed state and

[0052] Fig. 11 : a perspective view of a housing part of the interchangeable battery pack designed as an end cap in an internal view (Figure 11 a) and in an external view (Figure 11 b).

[0053] Description of the embodiments

[0054] Figure 1 shows a system comprising an energy storage unit 12 designed as an interchangeable battery pack 10 with an electromechanical interface 16 having a plurality of electrical contacts 14 and various electrical devices 18, each with an electromechanical interface 20 corresponding to the electromechanical interface 16 of the interchangeable battery pack 10. Figure 1 is intended to illustrate that the system is suitable for various electrical devices 18 operated with interchangeable battery packs 10, without limiting the invention. By way of example, a charger 22 and several electrical consumers 30 designed as a cordless vacuum cleaner 24, a cordless impact wrench 26 and a cordless light 28 are shown. In the context of the invention, however, a wide variety of power tools, gardening tools and household appliances can be considered as electrical consumers 30. The number of interchangeable battery packs 10 within the system is also variable.Thus, the system can also comprise several interchangeable battery packs 10. It should be noted again that the invention is also applicable to electrical consumers 30 that have purely resistive and / or capacitive electrical loads, so that the power tools shown here are to be understood merely as examples.

[0055] The removable battery pack 10 has an outer housing 32, which has the electromechanical interface 16 on a first side wall or its top side 34 for a tool-free—i.e., manually—detachable connection to the electromechanical interface 20 of the electrical device 18. For this purpose, the electromechanical interface 16 of the removable battery pack 10 has two guide rails 36, which, when inserted, are guided into corresponding guide grooves (not shown) of the electromechanical interface 20 of the electrical consumer 30 or the charger 22. In conjunction with the electrical consumer 30, the electromechanical interfaces 16, 20 primarily serve to discharge the removable battery pack 10, while in conjunction with the charger 22 they can be used to charge the removable battery pack 10.The precise design of the electromechanical interfaces 16, 20 depends on various factors, such as the voltage class of the interchangeable battery pack 10 or the electrical device 18 and various manufacturer specifications. For example, three or more electrical contacts 14 can be provided for energy and / or data transmission between the interchangeable battery pack 10 and the electrical device 18. Mechanical coding is also conceivable, so that the interchangeable battery pack 10 can only be operated with certain electrical devices 18. Since the mechanical design of the electromechanical interfaces 16, 20 of the interchangeable battery pack 10 and the electrical device 18 is irrelevant to the invention, it will not be discussed in further detail here. Both a person skilled in the art and an operator of the interchangeable battery pack 10 and the electrical device 18 will make the appropriate selection in this regard.

[0056] To dissipate heat generated during the charging or discharging process, the removable battery pack 10 has a sub-housing 38, which is preferably made of a thermally conductive material (e.g., a thermoplastic polyethylene such as PH-HD) and is partially surrounded by the outer housing 32. The sub-housing 38 forms a housing that is separate or separable from the outer housing 32 and is positively and / or force-fittingly connected to the outer housing 32. Additional housing parts in the form of detachable end caps 40 are provided on the end faces of the outer housing 32 and sub-housing 38 by means of screw connections; these end caps fix the sub-housing 38 in the outer housing 32.

[0057] The removable battery pack 10 and the charger 22 or the electrical consumer 30 have mutually corresponding electromechanical interfaces 16 and 20 with a plurality of electrical contacts 14, wherein a first of the electrical contacts 14 of the electromechanical interfaces 16, 20 serves as a power supply contact 42 to which a first reference potential Vi, preferably a supply potential V+, is applied, and a second of the electrical contacts 14 of the interfaces 16, 20 serves as a power supply contact 44 to which a second reference potential V2, preferably a ground potential GND, is applied (see Figure 2). The removable battery pack 10 can be charged by the charger 22 via the first and second power supply contacts 42, 44. The removable battery pack 10 can also be discharged via the first and second power supply contacts 42, 44 if the electrical device 18 is configured as an electrical consumer 30.The term "loadable" is intended to clarify that the potentials V+ and GND are not permanently applied to the power supply contacts 42, 44, particularly in the case of an electrical device 18 designed as an electrical consumer 30, but only after the electromechanical interfaces 16, 20 have been connected. The same applies to a discharged interchangeable battery pack 10 after connection to the charger 22.

[0058] In addition to the power supply contacts 42, 44, the electromechanical interfaces 16, 20 can also have further electrical contacts 14, which are designed in particular as signal or data contacts 46. Information about various operating parameters of the removable battery pack 10, such as the battery voltage Ußatt, the cell voltages Uceii, a temperature T measured in the removable battery pack 10, a charging or discharging current I, a coding, or the like, can be transmitted to the electrical load 30 or the charger 22 via the signal or data contacts 46 for evaluation there. Based on these operating parameters, the electronics of the electrical load 30 or the charger 22 can control or regulate the discharging or charging process.

[0059] Figure 2 shows the interior of the removable battery pack 10 shown in Figure 1 prior to its complete assembly. The sub-housing 38 of the removable battery pack 10 is designed to accommodate two so-called cell clusters 48. Each cell cluster 48 comprises a plurality N = 10 cylindrical energy storage cells 50 (see Figures 6 and 7a), which are arranged in a cell holder 52 and each have a cell voltage Uceii of 3.6 V. As already mentioned at the beginning, the battery voltage of the removable battery pack 10 is generally a multiple of the cell voltages of the energy storage cells, depending on their connection (parallel or series). The energy storage cells are preferably designed as lithium-based battery cells, e.g., Li-Ion, Li-Po, Li-Metal, or the like. However, the invention is also applicable to removable battery packs with Ni-Cd, Ni-MH cells, or other suitable cell types.In order to save installation space, the ten energy storage cells 50 of a cell cluster 48 are laterally offset from one another over four layers arranged one above the other, with two layers each having two energy storage cells 50 and two further layers each having three energy storage cells 50.

[0060] Each energy storage cell 50 has a positive and a negative cell pole 54 on each of its two end faces. The individual cell poles 54 of the energy storage cells 50 of a cell cluster 48 are electrically connected to one another via cell connectors 56 in such a way that a series and parallel connection of the energy storage cells 50 results in a resulting cluster voltage Uci of 18 V with a capacity of at least 6 Ah. Both cell clusters 48 are connected in series so that a battery voltage Ußatt of 36 V is achieved. The cell connectors 56 are designed as flat stamped sheets which are electrically connected, on the one hand, to the cell poles 54 via contact points 58 and, on the other hand, at an open end 60 to an electrical connection point of a printed circuit board 62 in a materially bonded manner, for example by means of soldering, resistance welding, cold welding or the like.

[0061] At least one of the cell connectors 56 has an SCM tap (not shown in detail) for single cell monitoring, which is integrally connected to the cell connector 56 and is preferably arranged between the open end 60 for electrical contact with the circuit board 62 and the contact points 58 for electrical contact with the cell poles 54 of the energy storage cells 50. The SCM tap is integrally connected, for example by soldering, to a cable, which in turn establishes an electrical connection to an SCM pre-stage of a corresponding electronics unit of the interchangeable battery pack 10 (not shown). To record the individual cell voltages Uceii, the SCM pre-stage switches sequentially between the individual SCM taps of the cell connectors 56, for example via integrated transistors, such that they are each connected to a positive and a negative cell pole 54 of the energy storage cell 50 or 52 to be measured.of the cell cluster 48 to be measured. The electronics of the interchangeable battery pack 10 can comprise an integrated circuit in the form of a microprocessor, ASIC, DSP, or the like for controlling or regulating the charging or discharging process. It is also conceivable for the control or regulation to be carried out by means of several microprocessors or at least partially by means of discrete components with corresponding transistor logic. In addition, the electronics can comprise a memory for storing the operating parameters. Since such electronics are known to those skilled in the art, they will not be discussed further here.

[0062] By means of the circuit board 62 and a busbar 64 arranged directly on its surface, the cell connector 54 of one of the two cell clusters 48, which is supplied with the first reference voltage Vi, is electrically connected to the power supply contact 42 of the electromechanical interface 16 (see also Figures 7a and 8). Accordingly, the cell connector 54 of the other cell cluster 48, which is supplied with the second reference voltage V2, is also electrically connected to the power supply contact 44 of the electromechanical interface 16 via another busbar 64 arranged directly on the surface of the circuit board 62.

[0063] Due to the limited space, the opposing cell connectors 56 of the two cell clusters 48 must be electrically insulated from one another to prevent any short circuits during later operation. At the same time, it is necessary to mechanically connect the two cell clusters 48, which are electrically connected in series, to create a stable structural unit that protects the two cell clusters 48 from vibrations, shocks, impacts, etc., particularly during use of the removable battery pack 10. These tasks are performed by a housing part designed as an insulating plate 66 arranged between the cell clusters 48 and manufactured using a two-component (2K) or three-component (3K) injection molding process. This eliminates the need for additional assembly devices to hold the individual cell clusters 48 in position during assembly of the removable battery pack 10.

[0064] Figure 3 illustrates the assembly according to Figure 2, consisting of the two cell clusters 48 and the insulating plate 66, in a disassembled structure, wherein an outer contour of the insulating plate 66 essentially corresponds to an envelope 68 of the cell clusters 48 in cross-section through a longitudinal axis 70 of the assembly. The assembly facilitates the subsequent assembly steps of the removable battery pack 10. By eliminating additional connecting elements such as screws, adhesives or the like, this enables a significant simplification and cost reduction in the assembly of the removable battery pack 10. The at least two injection-molded components of the insulating plate 66 are formed by a hard component 72 (for example a thermoplastic or duroplastic or duromer) and a soft component 74 (for example an elastomer such as rubber, silicone or the like).The hard component 72 essentially serves to stiffen the insulating plate 66, while the soft component 74 acts as mechanical damping or fixation as well as tolerance compensation. The soft component 74 has a hardness of 0 to 100 Shore A, preferably 30 to 70 Shore A. Furthermore, the soft component 74 can be used to seal dedicated areas of the removable battery pack 10 or the cell clusters 48. Figure 4a shows the insulating plate 66 consisting of the hard component 72 and the soft component 74 in a perspective detailed view. For the mechanical coupling of the two cell clusters 48, the hard component 74 has three locking hooks 76 on each side (see also Figure 3). Instead of the locking hooks 76, tabs, mushroom heads or corresponding projections and / or recesses, for example in the form of a tongue and groove principle, can alternatively be used for fastening to the cell clusters 48.In addition, the number of fastening elements can vary depending on the design of the cell clusters 48, for example depending on the number N of energy storage cells 50. The locking hooks 76 can, on the one hand, achieve good mechanical stabilization and, on the other hand, very simple and quick assembly of the structural units consisting of the cell clusters 48 and the insulating plate 66. Furthermore, in the event of damage to one of the cell clusters 48 or individual energy storage cells 50, disassembly and simplified replacement are possible. The locking hooks 76 and / or a plurality of mechanical links 78 are arranged on the insulating plate 66 in such a way that the cell clusters 48 can only be connected to the insulating plate 66 in accordance with a poka-yoke principle. This makes it possible to achieve increased process reliability during assembly in order to prevent any assembly errors that could possibly lead to damage to the cell clusters 48 orof the energy storage cells 50.

[0065] The soft component 74 is designed as a plurality M of elastic lamellae 80, which are arranged within the hard component 72 and are connected to one another via webs 82 of the same material. The plurality M of lamellae 80 preferably corresponds to the number N of energy storage cells 50 of at least one of the cell clusters 48 connected to the insulating plate 66. In this way, the individual energy storage cells 50 or their cell poles 54 and / or the cell connectors 56 connecting them or their contact points 58 can be effectively protected from mechanical vibrations, blows and impacts or the like during use of the removable battery pack 10. In addition, the heat generated during operation of the electrical consumer 22 or during charging of the removable battery pack 10 can be dissipated or distributed. In order to simplify the pressing or potting of the lamellae 80 in the hard component 72 of the insulating plate 66 and, if necessary,To ensure an improved sealing function of the insulating plate 66, the lamellae 80 are circular. Their position corresponds to the cell poles 54 of the cell clusters 48 connected to the insulating plate 66. Furthermore, it can be provided that the pressing takes place in the assembled state of the insulating plate 66, so that the energy storage cells 50 and / or the cell connectors 56 can be held in position and the robustness of the removable battery pack 10 can be further improved. Instead of the lamellae 80, the domes 83 shown in Figure 4b can also be used as part of the soft component 74.

[0066] Figure 5 shows a section through the structural unit formed from the two cell clusters 48 and the insulating plate 66 along the longitudinal axis 70 (see Figure 3). The locking hooks 76 engage behind corresponding recesses in the cell holders 52 of the cell clusters 48 such that, when locked in place, they form a positive connection between the two cell clusters 48. At the same time, the locking hooks 76 are subjected to a spring force F generated by the lamellae 80 of the soft component 74 at the cell poles 54 of the energy storage cells 50 or at the contact points 58 of the cell connectors 56. The lamellae 80 thus stabilize the structural unit on the one hand and provide a seal on the other.

[0067] Figure 6 shows the assembly of the removable battery pack 10 according to Figure 2 inserted into the sub-housing 38. For this purpose, the sub-housing 38 is designed to be open at least on one end face 84, while its remaining sides enclose the assembly consisting of the cell clusters 42 and the insulating plate 66. Furthermore, the sub-housing 38 carries the electrical contacts 14 designed as first and second power supply contacts 42, 44 and as signal or data contacts 46. The electrical contacts 14 are designed as contact tulips, each of which is electrically connected to the busbars 64 through a recess 86 in the sub-housing 38. To enable the contact tulips to be welded on, the busbars 64 must be accessible on both sides at the corresponding contact points. The busbars 64 are in turn overmolded by the material of the sub-housing 38 on a side adjacent to the printed circuit board 62 of the assembly.For this reason, the material of the sub-housing 38 must not be electrically conductive. If the removable battery pack 10 with its electromechanical interface 16 is inserted into the corresponding mating interface 20 of the electrical device 18 (see Figure 1), the contacts 14 of the electromechanical interfaces 20 of the electrical device 18, which are designed as flat metal webs, engage in the contact tulips to establish an electrical connection. By overmolding the busbars 64, the area around them is sealed accordingly and prevents liquid and dirt from entering the interior of the removable battery pack 10. This also provides increased protection for sensitive components of the removable battery pack 10, such as the electronics or the energy storage cells 50, through appropriate insulation from the environment. In addition, increased heat spread orDissipation and thus improved cooling in the contact area are possible through the direct coupling of the busbars 64 to the outer housing 32 of the removable battery pack 10 and / or the electrical load 22. Furthermore, the busbars 64 injected into the sub-housing 38 facilitate the assembly of the removable battery pack 10 because the assembly consisting of the cell clusters 48 and the insulating plate 66 can be very easily inserted laterally into the sub-housing 38 through the opening on its front side 84.

[0068] Figure 7 shows a section through the fully assembled removable battery pack 10 along the longitudinal axis 70. The two end caps 40 seal the sub-housing 38 at its open end faces 84 by means of a sealing lip 88. The sealing lip 88 is preferably made of an elastomer such as rubber, silicone, or the like and engages in a groove 90 surrounding the open end faces 84 of the sub-housing 38 and the end caps 40. Figure 7b illustrates this using an enlarged detail of the area marked in Figure 7a. In addition, Figure 6 shows the groove 90 surrounding the end face 84 of the sub-housing 38 in a perspective view. The sealing lip 90 is preferably already injection-molded or inserted into the groove 90 of the end caps 90 before the end caps 90 are mounted.If the end caps 40 are mounted, for example by screwing, on the outer housing 32 of the removable battery pack 10, the sealing lip 90 is pressed into the groove 90 of the sub-housing 38 and seals the area surrounding it accordingly. The end caps 40 particularly advantageously enable simple maintenance or repair of the removable battery pack 10 because defective components can be easily replaced by removing at least one of the end caps 40, in that the assembly consisting of the cell clusters 48 and the insulating plate 66 can be pulled laterally out of the open end face 84 of the sub-housing 38. Furthermore, the sealing lip 88, in conjunction with the replaceable end caps 40, ensures a high level of protection against environmental influences.

[0069] With reference to Figure 8, the sub-housing 38 has a pressure equalization opening 92 on one side, in particular on a side facing the circuit board 62, through which pressure equalization can take place between the sub-housing 38, which is sealed by the end caps 40, and the environment. This prevents damage to the sensitive components of the removable battery pack 10, such as the electronics or the energy storage cells 50, due to any unfavorable pressure conditions inside the sub-housing 38 compared to the environment. The pressure equalization opening 92 is sealed by a pressure equalization membrane 94. This allows gas and moisture exchange between the sub-housing 38 and the environment on the one hand, but on the other hand, the special material properties of the pressure equalization membrane 94 can prevent water and dirt from entering the interior of the removable battery pack 10.Air-permeable, fine-pored membranes made of PTFE (polytetrafluoroethylene) are particularly suitable as pressure equalization membranes 94. These membranes can also be coated oleophobically on at least one side, so that certain liquids roll off their outer surface.

[0070] Figure 8 also shows a temperature measurement concept for the removable battery pack 10 using a flexible film 100 with two integrated temperature sensors 102 configured as NTCs. The flexible film 100 is guided through two recesses 96 of the circuit board 62 on its upper side for electrical contact. The temperature sensors 102 of the flexible film 100 are each pressed against the outer surface of the energy storage cells 50 to be measured by a foam element 104 supported on the circuit board 62. The flexible film 100 is electrically connected via the circuit board 62 to the electronics of the removable battery pack 10, which evaluates the measured temperature of the energy storage cells 50 and controls the charging or discharging process accordingly.

[0071] According to Figure 9, the circuit board 62 is provided with recesses 96 for the busbars 64, into which the busbars 64 engage with at least one wave-shaped, in particular U-shaped, section 98. At least one section 98 is located below the surface of the circuit board 62. This allows strain and / or shock relief for the busbars 64 to be accommodated very efficiently and easily in the installation space of the circuit board 62, which enables a particularly compact design of the interchangeable battery pack 10. Furthermore, greater mobility of the busbars 64 is achieved.If, for example, a force is introduced into an electrical connection point 106 of the busbar 64, which is designed as a welding or soldering point, for example caused by an impact on the removable battery pack 10 or the electrical load 22, the busbar 64 can deform elastically in the region of the at least one recess 96 of the printed circuit board 62 in order to dissipate the introduced force as deformation energy. This relieves the load on the electrical connection point 106 and the busbar 64. Corresponding connection points on the printed circuit board can also be relieved. The U-shaped sections 98 of the busbars 64 dip into the recesses 96 of the printed circuit board 62 in such a way that, viewed from the side on which the busbars 64 are arranged, they each protrude on the opposite side of the printed circuit board 62.For illustration, Figure 9 also shows the temperature measurement concept of the removable battery pack 10 explained in Figure 8 using the flex film 100 and the two temperature sensors 102.

[0072] Figure 10 shows a section of the busbar 64 in the area of ​​the U-shaped section 98 according to Figure 9 in the undeformed and deformed state, with the deformation shown being significantly exaggerated for clarity. Particularly advantageously, the U-shaped section 98 of the busbar 64 has a depth extension T that is at least as large as its length extension L along the busbar 64. This makes it possible to increase the spring action of the busbar 64 and thus the protection of the electrical connection point 106 or to adapt it to any specifications.

[0073] Instead of a U-shaped section 98, comparable wave-shaped sections, in particular V-, W-, or meander-shaped sections 98, can also be used. In addition, a wave shape in this context should also be understood to mean a shape with steep rectangular flanks. Furthermore, it is not absolutely necessary for the entire section 98 to lie below the surface of the circuit board 62. In particular with a W- or meander shape, it is conceivable that the at least one section 98 partially protrudes from the surface of the side on which the busbar 64 is located. Additionally or alternatively, the at least one section 98 of the busbar 64 can be formed from a different, electrically conductive material than the rest of the busbar 64. For example, it is conceivable for the busbar 64 to be formed from copper and the section 98 from aluminum, tungsten, silver, gold, or the like.Additionally or alternatively, it can be provided that the at least one section 98 of the busbar 64 has a cross-section and / or a thickness that differs from the cross-section and / or the thickness of the remaining busbar 64. Thus, a smaller cross-section and / or a smaller thickness of the section 98 offers greater flexibility and spring action, while a larger cross-section and / or a greater thickness can be used, particularly in conjunction with a copper mesh as an additional material.

[0074] Figure 11a shows a perspective view of the housing part of the removable battery pack 10 according to Figure 1, designed as an end cap 40, in an interior view. Figure 11b shows the end cap 40 in an exterior view. The end cap 40 is manufactured using a three-component injection-molding process and thus consists of three different injection-molded components. A base body 108 of the end cap 40 is formed from the hard component 74 and is overmolded, in particular almost completely, by the soft component 74 at least on a first side, in particular an outer side, of the end cap 40. This results in improved handling for an operator, for example, by providing more grip, especially with wet hands. In addition, overmolded on the outer side of the base body 108 designed as a hard component 72 increases robustness against impacts, for example, if the removable battery pack 10 or the electrical load 30 is dropped.The hard component 72 also has a plurality of recesses 110 designed as drilled holes, which serve to detachably fasten the end cap 40 to the outer housing 32 by means of corresponding screw connections. For this purpose, the recesses 110 are not overmolded by the soft component 74. The soft component 74 forms the sealing lip 88 injected into the groove 90 of the hard component 72 on a second side, in particular an inner side, of the end cap 40 (see Figure 7). This improves the sealing of the removable battery pack 10 or the electrical load 30 against moisture, liquids, dust, and other forms of dirt, and also significantly simplifies the assembly of the end cap 40, since the sealing lip 88 does not have to be separately inserted into the groove 90.

[0075] The soft component 74 forms a plurality of damping elements 114 on the inside of the end cap 40, which are molded onto projections 112 of the hard component 72. These damping elements serve to axially and / or radially dampen the energy storage cells 50. This makes the removable battery pack 10 more robust against any shocks and impacts, as well as vibrations, that may occur when working with the electrical consumer 30. Furthermore, the damping elements 114 serve to better secure the energy storage cells 50 or the cell clusters 48 within the removable battery pack 10.

[0076] The usability of the removable battery pack 10 can be increased by a third injection-molded component 116 of the end cap 40 being a further soft component made of a transparent or translucent, in particular thermoplastic, elastomer. Thus, the third injection-molded component 116 can serve, for example, as a charge level indicator 118 of the removable battery pack 10, wherein the light from individual LEDs (not shown) mounted on the circuit board 62 of the removable battery pack 10 is guided outward by the third injection-molded component 116 designed as a light guide 120. For this purpose, the third injection-molded component 116 is injected into a recess 122 of the hard component 72, which is not overmolded by the soft component 74. This particularly advantageously increases the robustness of the removable battery pack 10 through additional sealing in the area of ​​the charge level indicator 118.Additionally, the charge level indicator 118 on the outside of the end cap 40 in the area of ​​the recess 122 may be covered with a translucent film to visually conceal the transition between the third injection-molded component 116 and the hard component 72. Particularly advantageously, the film is color-matched to the soft component 74, so that no visual difference is discernible between the soft component 74 and the charge level indicator 118 when the LEDs are switched off.

[0077] A further improvement in the usability of the removable battery pack 10 can be achieved by injecting at least one actuating element 124 and / or at least one optical separating element 126 into the third injection-molded component 116, which is formed in particular from the hard component 72 or a comparable thermoplastic. Thus, for example, the charge level indicator 118 can be activated for a defined time window by briefly pressing the actuating element 124. The at least one optical separating element 126 makes it possible to more clearly distinguish between different charge levels of the removable battery pack 10, because this prevents stray light between the individual LEDs indicating the charge levels.

[0078] Finally, it should be noted that the exemplary embodiments shown are not limited to Figures 1 to 11 or to the shape, number, and size of the energy storage cells 50 and the busbars 64 shown therein. Accordingly, the number and shape of the cell clusters 48 of the removable battery pack 10 can also vary. This also applies in particular to the sub-housing 38, the end caps 40, the insulating plate 66, and the printed circuit board 62 of the removable battery pack 10. For example, depending on the number of cell clusters 48, several insulating plates 66, printed circuit boards 62, and sub-housings 38 can be used within the outer housing 32 of the removable battery pack 10. The design and number of the end caps 40 are also not limited to the exemplary embodiments shown.

Claims

Claims 1. Energy storage unit (12) for an electrical consumer (30), comprising a plurality (N) of energy storage cells (50), wherein each energy storage cell (50) has two electrical cell poles (54) and the electrical cell poles (54) of at least two energy storage cells (50) are electrically connected to one another in a series or parallel circuit as a cell cluster (48) via at least one cell connector (56), characterized in that the energy storage unit (12) has at least two cell clusters (48) which are connected to one another by means of an insulating plate (66) produced in a two-component or three-component injection molding process.

2. Energy storage unit (12) according to claim 1, characterized in that a first of the at least two components of the insulating plate (66) is designed as a hard component (72) and a second of the at least two components is designed as a soft component (74).

3. Energy storage unit (12) according to claim 2, characterized in that the soft component (74) has a hardness of 0 to 100 Shore A, preferably of 30 to 70 Shore A.

4. Energy storage unit (12) according to claim 2, characterized in that the hard component (72) has a plurality of locking hooks (76) for fastening to the at least two cell clusters (48).

5. Energy storage unit (12) according to claim 4, characterized in that the locking hooks (76) and / or a plurality of mechanical links (78) are arranged on the insulating plate (66) in such a way that the cell clusters (48) can only be connected to the insulating plate in the sense of a poka-yoke principle (66). Energy storage unit (12) according to one of the preceding claims 2 or 3, characterized in that the soft component (74) is designed as a plurality (M) of elastic lamellae (80) and / or calottes (83) which are arranged within the hard component (72) and which are connected to one another in particular via webs (82) of the same material. Energy storage unit (12) according to claim 6, characterized in that the plurality (M) of lamellae (80) and / or calottes (83) corresponds to the number (N) of energy storage cells (50) of at least one of the cell clusters (48) connected to the insulating plate (66). Energy storage unit (12) according to one of the preceding claims 6 or 7, characterized in that the lamellae (80) and / or domes (83) are circular and their position corresponds to the electrical cell poles (54) of the cell cluster (48) connected to the insulating plate (66).Energy storage unit (12) according to one of the preceding claims 6 to 8, characterized in that the lamellae (80) and / or caps (83) are pressed together in the assembled state of the insulating plate (66). Electrical consumer (30) with an energy storage unit (12) according to one of the preceding claims. System consisting of an electrical consumer (30) designed as a handheld power tool (24, 26, 28) and at least one energy storage unit (12) designed as a removable battery pack (10) according to one of the preceding claims 1 to 9.

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