Energy storage unit for electrical consumer

Abstract

The invention relates to an energy storage unit (16) for an electrical consumer (10), comprising at least one first energy storage cell (20), at least one first temperature sensor (82) for detecting a temperature (T) of the at least one first energy storage cell (20), and a circuit board (58) for receiving the at least one first temperature sensor (82). According to the invention, the at least one first temperature sensor (82) and the printed circuit board (58) are surrounded, in particular completely, by a thermally conductive potting compound (60), the thermally conductive potting compound (60) being configured such that it is in thermal contact with the at least one first energy storage cell (20), in particular at the location of the at least one first temperature sensor (82).

Description

Technical Field

[0001] The present invention relates to an energy storage unit for an electrical appliance according to independent claim 1. The energy storage unit comprises at least one first energy storage cell, at least one first temperature sensor for detecting the temperature of at least one first energy storage cell, and a circuit board for receiving at least one first temperature sensor. Background Art

[0002] A number of electrical consumers are operated with the aid of fixed integrated energy storage units (also called batteries or battery packs) or energy storage units that can be replaced by an operator without tools (hereinafter referred to as replaceable battery packs), which are discharged by the electrical consumers and can be recharged with the aid of a charger. Typically, such energy storage units consist of a plurality of energy storage cells connected in series and / or in parallel in order to achieve the required battery voltage or capacity. If the energy storage cells are designed, for example, as lithium-ion batteries, high power and energy density can be achieved particularly advantageously. On the other hand, in order to avoid electrical faults, such batteries also need to comply with strict specifications with regard to maximum charging and discharging currents, voltages and temperatures. If, for example, the detected temperature is outside a predetermined limit value, the discharge or charging process of the energy storage unit is interrupted or at least limited.

[0003] In modern battery-operated electrical consumers, the cell voltages of parallel-connected energy storage cells of a so-called cell cluster of an energy storage unit are evaluated, for example, by a monitoring unit. The term "cell voltage" is therefore to be understood as meaning not only the voltage of a single energy storage cell, but also the voltage of a cell cluster consisting of parallel-connected energy storage cells. Such so-called single cell monitoring (SCM) is known, for example, from WO 20043386 A1, wherein redundant monitoring also prevents dangerous operation of replaceable battery packs in the event of a fault. Summary of the invention

[0004] The object of the present invention is to achieve particularly robust and reliable temperature detection in an energy storage cell for safe operation in combination with the simplest possible production of the energy storage cell.

[0005] To achieve the above-mentioned object, it is proposed that at least one first temperature sensor and the printed circuit board are in particular completely surrounded by a heat-conducting potting material, wherein the potting material is configured such that it is in thermal contact with the at least one first energy storage cell, in particular at the location of the at least one first temperature sensor. As a result, it is particularly advantageously possible to achieve simplified and cost-effective production of the energy storage unit in combination with reliable and safe temperature monitoring.

[0006] In addition, the present invention also relates to an electrical consumer having an energy storage unit according to the present invention and a system consisting of an electrical consumer configured as a handheld machine tool and at least one energy storage unit configured as a replaceable battery pack. However, in the context of the present invention, electrical consumers are generally understood to be all devices that are supplied with electrical loads by means of energy storage units, such as replaceable battery packs or fixed integrated battery packs. Here, the electrical load can be configured as a mainly inductive load in the form of a motor drive. It is also possible to consider mainly resistive or capacitive loads. In particular, an electronically commutated electric motor (so-called EC or BLDC motor) is considered as a motor drive, and its individual phases are controlled by at least one power transistor via pulse width modulation to control or regulate its speed and / or its torque. In this context, the present invention can be applied to a battery-operated machine tool for machining a workpiece by means of an electrically driven insertion tool. In this context, the electric machining device can be configured not only as a handheld machine tool, but also as a fixed machine tool. Typical machine tools in this context are handheld or vertical drills, screwdrivers, impact drills, planers, angle grinders, oscillating grinders, battery polishers, etc. However, electrical consumers also include gardening and construction equipment such as lawn mowers, lawnmowers, pruning saws, motors and trench cutters, blowers, robot crushers and excavators, etc., as well as measuring devices such as laser rangefinders, wall scanners, etc. Furthermore, the invention can be applied to household appliances such as vacuum cleaners, blenders, etc. and electrically driven road and rail vehicles such as electric bicycles, electric scooters, electric assisted vehicles, electric and hybrid vehicles, etc., as well as aircraft and ships having an energy storage unit according to the invention.

[0007] The voltage level of the energy storage unit is derived from the connection mode (parallel or series) of the individual energy storage cells integrated in the energy storage unit and is usually an integer multiple (≥1) of the voltage of the individual energy storage cells. The energy storage cell is usually constructed as a primary battery, which has a structure in which one battery pole is located at one end and the other battery pole is located at the opposite end. In particular, the energy storage cell has a positive battery pole at one end and a negative battery pole at the opposite end. The energy storage cell is preferably constructed as a lithium-based battery, such as a lithium-ion battery, a lithium polymer battery, a lithium metal battery, etc. However, the present invention can also be applied to energy storage units with nickel-cadmium batteries, nickel-hydrogen batteries or other suitable battery types. In common lithium-ion energy storage cells with a cell voltage of 3.6V, voltage levels of 3.6V, 7.2V, 10.8V, 14.4V, 18V, 36V, etc. are obtained, for example. The energy storage cell is preferably constructed as a round battery that is at least substantially cylindrical, wherein the battery poles are arranged at the ends of the cylinder. However, the invention is not dependent on the type and structure of the energy storage cell used, but can be applied to any energy storage unit and battery, for example, in addition to round batteries, also to prismatic batteries, soft-pack batteries, etc. The DC voltage value depends primarily on the typical cell voltage of the energy storage cell used. Thus, for example, for soft-pack batteries and / or batteries with different electrochemical compositions, the voltage value can deviate from that of an energy storage unit equipped with lithium-ion batteries.

[0008] If the energy storage unit is configured as a replaceable battery pack, it is removably connected to the corresponding complementary electromechanical interface of the electrical consumer or charger in a force-locking and / or form-locking manner via the electromechanical interface of the replaceable battery pack. "Removable connection" should be understood in particular as a connection that can be removed and established manually without tools, i.e., manually. The electromechanical interface and its removable connection for receiving force-locking and / or form-locking should not be the subject of the present invention. Those skilled in the art will select an appropriate embodiment for the electromechanical interface according to the power or voltage level of the electrical consumer and / or the replaceable battery pack, so that it will not be discussed in detail here. Therefore, the embodiments shown in the drawings are only to be understood as exemplary, and therefore, in particular, interfaces with more electrical contacts than those shown can also be used.

[0009] In one embodiment of the invention, at least one first temperature sensor is arranged on a circuit board layer of the circuit board, and the potting material has a recess on the side of the circuit board opposite to the circuit board layer in the region of the at least one first temperature sensor, in particular for thermally isolating the circuit board or the at least one first temperature sensor from the housing of the energy storage unit or the electrical consumer. In a particularly advantageous manner, the heat capacity in the vicinity of the temperature sensor can thereby be reduced in order to avoid or at least reduce temperature influences of other components and / or the housing of the energy storage unit or the electrical consumer on the temperature sensor.

[0010] The recess can be designed so that a cavity is formed between the casting material and the housing, which cavity limits the distance of the casting material from the housing at least in the region of the at least one first temperature sensor. Thus, possible damage to the temperature measurement by temperature influences acting on the housing can be further reduced or avoided.

[0011] In addition, a further temperature sensor can be arranged on the printed circuit board, which is spaced apart from the first temperature sensor so that it detects the temperature of a further energy storage cell, wherein the further temperature sensor is surrounded by the potting material so that the potting material is in thermal contact with the further energy storage cell, in particular at the location of the further temperature sensor. Thus, a plurality of energy storage cells can be monitored in the sense of hot single-cell monitoring and, if necessary, these energy storage cells can be individually deactivated by corresponding switching elements on the printed circuit board when a predetermined temperature limit value is exceeded or fallen below.

[0012] In order to optimize the thermal conductivity between the temperature sensor and the energy storage cell, the thermal contact surface of the potting material is adapted to the outer contour of the energy storage cell. If the energy storage cell is designed as a cylindrical round battery, for example, an optimized thermal conductivity is obtained when the thermal contact surface of the potting material has a shape complementary thereto, in particular a concave shape, in order to form a surface that is as large as possible, which conducts the temperature of the energy storage cell to the temperature sensor. In addition, this form fit allows simplified assembly of the circuit board, because the correspondingly preformed potting material causes reproducible positioning on the energy storage cell.

[0013] An alternative or additional possibility for reducing or avoiding the impairment of the temperature measurement by temperature influences acting on the housing is that the potting material has at least one protruding contact point for the housing of the energy storage unit or the electrical consumer on the side facing away from the at least one first energy storage cell, in order to form an air gap between the housing and the potting material. The air gap can also be formed by two contact points of the potting material, wherein the temperature sensor is arranged substantially centrally between the two contact points.

[0014] In one embodiment of the invention, the casting material is designed as an elastic thermoplastic. Such a thermoplastic can be produced, for example, by so-called low-pressure molding. Here, the circuit board and its electrical connection points are placed in a concave casting mold and then filled with a hot, viscous polymer. After the polymer cools, a robust and partially elastic shell is formed, which ensures very good protection against corrosion caused by moisture, fingerprints, etc. The elasticity of the thermoplastic can compensate for tolerances between the circuit board or the temperature sensor and the energy storage cell, which improves the thermal conductivity.

[0015] In order to keep the structure of the energy storage unit as compact as possible, the printed circuit board surrounded by the potting compound is arranged between two adjacent energy storage cells in such a way that it does not protrude beyond the envelope formed by the two energy storage cells in cross section.

[0016] Typically, the battery poles of at least two energy storage cells of the energy storage unit are electrically connected to each other in series or in parallel via at least one cell connector. The cell connector is electrically connected to the battery pole by means of a material-locked connection, such as soldering, cold welding, etc. The cell connector is constructed as a flat stamped sheet or sheet, which itself is electrically connected to the circuit board of the energy storage unit via an electrical connection point of a circuit board (PCB-printed circuit board) for monitoring the energy storage cells. The electrical connection between the circuit board connection point and the cell connector is also achieved by material locking with the aid of cables, flat ribbon lines, bonding wires, stamped grids, etc. Flexible printed circuits (FPCs) are also used in some cases.

[0017] In an alternative embodiment of the invention, the object may therefore be to achieve a particularly robust electrical connection of the individual energy storage cells of the energy storage unit to the printed circuit board in conjunction with the simplest possible production of the energy storage unit.

[0018] To achieve this objective, the printed circuit board including the electrical connection points is completely surrounded by the potting compound. In this way, on the one hand, the electrical connection between the printed circuit board and the cell connector can be well protected against contamination and short circuits, and on the other hand, complex and error-prone soldering during assembly of the energy storage unit can be avoided.

[0019] In one embodiment of the invention, the potting material is formed from a low-pressure thermoplastic. During low-pressure molding, the circuit board and its electrical connections are placed in a negative mold and then filled with a hot, viscous polymer. After the polymer cools, a robust and partially elastic shell is formed, which ensures very good protection against corrosion caused by moisture, fingerprints, etc. Alternatively, it is also conceivable that the potting material is preferably formed from a silicone material.

[0020] In addition, at least one cell connector has an electrical tap for individual cell monitoring (SCM) of the energy storage cell. Since an additional material-locked connection for the SCM tap is no longer required during assembly of the energy storage unit, the tap is at least partially protected against contamination and / or corrosion, so that the risk of accidental discharge of the energy storage unit or individual energy storage cells can be significantly reduced.

[0021] In addition, at least one cell connector has a tolerance compensation structure for adapting to the length of the energy storage cell. Since the electrical connection between the cell connector and the circuit board is completed when the circuit board is equipped and each component has a fixed length, the tolerance compensation structure provides the possibility of compensating for the length tolerance of the energy storage cell, the circuit board and / or their connection parts. Here, the tolerance compensation structure of the cell connector parallel to the longitudinal axis of each energy storage cell can be constructed as a U-shaped, zigzag or wavy fold.

[0022] The present invention also relates to a method for manufacturing an energy storage unit for an electrical appliance, wherein the energy storage unit has a plurality of energy storage cells, wherein each energy storage cell has two battery poles and the battery poles of at least two energy storage cells are electrically conductively connected to each other in series or in parallel via at least one cell connector, and a circuit board having at least one electrical connection point for electrical connection of at least one cell connector. With the above advantages, in one method step, at least one cell connector is first electrically connected to the electrical connection point, in particular in a material-locked manner. In a subsequent method step, the circuit board together with at least one electrical connection point is cast with a casting material, in particular completely, and arranged parallel to the longitudinal axis of the energy storage cell, so as to connect at least one cell connector to the battery poles of at least two energy storage cells in a material-locked manner. In the context of the present invention, a material-locked connection should be understood in particular as an electrical connection produced by soldering, cold welding, etc.

[0023] In a method step of the method of the present invention, it is additionally provided that the circuit board is electrically connected to at least one other circuit board by means of a flexible circuit, in particular a multi-core flat ribbon cable, before the casting with the casting material. The other circuit board can, for example, have a plurality of electrical contacts configured as an electromechanical interface of an energy storage unit of a replaceable battery pack for contacting an electrical appliance or a charger. After the casting with the casting material, in a method step, the circuit board and at least one other circuit board are arranged substantially perpendicularly to each other around the energy storage cell. Instead of a flexible circuit, the other circuit board can also be configured as a flexible circuit board and be directly electrically connected to the circuit board, in particular materially locked.

[0024] In a further alternative embodiment of the invention, the object may be to enable particularly simple and precise temperature detection of an energy storage unit, in particular of an energy storage cell of the energy storage unit, for safe operation of the energy storage unit.

[0025] In order to solve this problem, at least one first temperature sensor is arranged on a side edge or on a circuit board layer in close proximity to a side edge for thermal coupling with at least one energy storage cell. Since the accuracy of the temperature detection depends on the thermal conductivity between the energy storage cell and the temperature sensor, the invention enables the heat generated during the charging or discharging process to be transferred from the energy storage cell to the temperature sensor in a targeted and as little-loss-as possible manner in a particularly advantageous manner. At the same time, the proposed solution is very cost-effective, since no separate mounting device or adhesive connection is required.

[0026] In another embodiment, the circuit board unfolds a circuit board plane, wherein the longitudinal axis of at least one energy storage cell, in particular a plurality of energy storage cells arranged in parallel, is oriented perpendicular to the circuit board plane. In addition, the side edge can be adapted to the outer contour of at least one energy storage cell at least in the region of at least one temperature sensor. In addition or alternatively, the side edge has at least one contact point with at least one energy storage cell. In this way, an optimized thermal contact of the temperature sensor positioned on the side edge can be achieved according to the outer contour of at least one energy storage cell.

[0027] In addition, the thermal contact between at least one temperature sensor and at least one energy storage cell is improved in the following manner, that is, the circuit board has at least one notch around at least one first temperature sensor, and the notch causes a spring force of the side edge relative to at least one energy storage cell, so that at least one energy storage cell deforms the side edge and / or the notch by pressure when the circuit board is assembled. When the side edge is deformed, the side edge is preferably constructed to be compressed in the plane of the circuit board. The at least one temperature sensor is always optimally maintained on the energy storage cell by pressure and a spring force acting in opposition to the pressure. In addition, the notch can cause thermal decoupling of at least one temperature sensor from the rest of the circuit board.

[0028] Particularly advantageously, at least one first temperature sensor is designed as a surface mounted device (SMD) component, which is arranged on at least one circuit board layer or directly in a recess of a side edge. SMD components are very compact and therefore allow particularly space-saving and cost-effective assembly in mass production.

[0029] The thermal coupling can be further improved in that the side edge has a thermally conductive coating at least in the vicinity of the at least one first temperature sensor.

[0030] A supplementary embodiment of the invention provides that a further temperature sensor is arranged on the side edge or another side edge of the circuit board, wherein the further temperature sensor is spaced apart from the first temperature sensor so that it detects the temperature of the further energy storage cell largely independently of the first energy storage cell, in particular. Thus, a plurality of energy storage cells can be monitored in the sense of hot single cell monitoring and, if necessary, these energy storage cells can be individually deactivated by corresponding switching elements on the circuit board when a predetermined temperature limit value is exceeded or fallen below.

[0031] In order to reduce or avoid distortion of the temperature detection, it can also be provided that the circuit board has at least one further recess around the at least one first temperature sensor and / or the further temperature sensor for thermal decoupling. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In the following Figure 1 to Figure 13 is explained by way of example, wherein the same reference numerals in the figures represent the same components having the same function.

[0033] The accompanying drawings show:

[0034] Figure 1 : A three-dimensional view of an electrical appliance configured as a drill hammer according to the prior art;

[0035] Figure 2 : A three-dimensional view of an electrical appliance configured as a multifunctional tool according to the prior art;

[0036] Figure 3 : A three-dimensional view of an energy storage unit configured as a 12V replaceable battery pack according to the prior art;

[0037] Figure 4 : A three-dimensional view of an energy storage unit configured as an 18V replaceable battery pack according to the prior art;

[0038] FIG5 : The energy storage unit according to the present invention before assembly ( Figure 5a ) and after assembly ( Figure 5b ) a perspective view of a first embodiment of an inner member;

[0039] Figure 6 : A detailed view of the internal components of the energy storage unit according to the present invention according to FIG. 5 ;

[0040] Figure 7 : According to Figure 5 and Figure 6 A three-dimensional view of a cell connector of an energy storage unit according to the present invention;

[0041] Figure 8 : A cross section of an energy storage unit according to the present invention at a height of approximately half the length of the energy storage unit;

[0042] Fig. 9 :According to Figure 5 to Figure 8 A detailed perspective view of the internal components of the energy storage unit according to the present invention;

[0043] Fig.10 : A front view of another embodiment of an energy storage unit according to the present invention;

[0044] Figure 11: According to Fig.10 Detailed views of various alternative configurations of the circuit board of the energy storage unit according to the invention ( Figures 11a to 11d );

[0045] Fig.12 :according to Fig.10 A detailed view of another configuration of a circuit board of an energy storage unit according to the present invention;

[0046] Figure 13: According to Fig.10 Detailed views of various alternative configurations of the side edges of the circuit board of the energy storage unit according to the present invention ( Figures 13a to 13d ). DETAILED DESCRIPTION

[0047] exist Figure 1 1 shows an electrical load 10 by way of example, which is configured as a hammer drill 12 having a housing 14. In addition to an impact mechanism not shown in detail, which is driven by an electric motor not shown in detail, in particular a brushless DC motor (electronic commutation-EC or brushless DC-BLDC), an energy storage unit 16 is arranged in the housing 14 of the hammer drill 12 for supplying energy to the electric motor and the electronic components (not shown) for controlling the electric motor, wherein the energy storage unit 16 is configured as a fixedly integrated battery pack 18 that cannot be replaced by an operator. The battery pack 18 may include a single energy storage cell 20 or a plurality of energy storage cells 20 (see FIGS. 5, Figure 8 and Fig.10 As explained at the beginning, the battery voltage U of the energy storage unit 18 Batt Usually, the single or cell voltage U of a single energy storage cell 20 is determined according to its interconnection mode (parallel or series). Cell The energy storage cell 20 is preferably a lithium-based battery, such as a lithium-ion battery, a lithium polymer battery, a lithium metal battery, etc., but the present invention can also be applied to an energy storage unit 18 having a nickel-cadmium battery, a nickel-hydrogen battery or other suitable battery types.

[0048] The speed and / or torque of an electric motor designed as an EC motor can be controlled or regulated, for example, by means of an electronic component and an inverter controlled by the electronic component (e.g., an H-bridge, a B6 bridge, etc., composed of semiconductor switches) according to the main switch 22 via pulse width modulation (PWM). Since the working method of PWM control is known to those skilled in the art, it will not be discussed in further detail here. In addition, other control or regulation methods for corresponding electric motors are also known without limiting the present invention.

[0049] Figure 2 Another embodiment of an electrical appliance 10 in the form of a motor-driven multifunctional tool 24 is shown. Instead of a single main switch 22, the main switch is divided into a simple on-off switch arranged on the upper side of the housing 14 and a speed regulator arranged on the side of the housing 14. Figure 1 Another essential difference of the hammer drill 12 shown in FIG. 1 is the replaceability of the energy storage unit 16, which is designed as a replaceable battery pack 26. For a tool-free (ie manually) detachable connection to the multi-function tool 24, the replaceable battery pack 26 has an electromechanical interface 28 (see also the description according to FIG. 1 ). Figure 3 and Figure 4The electromechanical interface can be plugged into an electromechanical interface 30 of the multifunctional tool 24, which is configured as a socket. If the replaceable battery pack 26 is fully inserted, it can supply the multifunctional tool 26 or its motor and electronic components with the required battery voltage U Batt An inserted replaceable battery pack 26 is to be understood in particular to mean a replaceable battery pack 26 whose electromechanical interface 28 , in the connected state to the load 10 , is connected to a correspondingly complementary electromechanical interface 30 of the load 10 .

[0050] It should be noted again that the present invention can also be used for electrical consumers having purely resistive and / or capacitive electrical loads, so that the electric tool shown here is to be understood only as an example and primarily serves to illustrate different types of energy storage cells 20 and their use.

[0051] exist Figure 3 and Figure 4 2 shows two different replaceable battery packs 26 in a three-dimensional view. The two replaceable battery packs 26 differ in particular in their battery voltage U Batt , capacity and its electromechanical interface 28.

[0052] Figure 3 The battery voltage U is shown to be 10.8V (nominal 12V). Batt The replaceable battery pack 26 has a housing 14 in which three cylindrical energy storage cells 20 are arranged (see FIGS. 5 and 6 ). Figure 8 ), these energy storage cells have a battery voltage U of 3.6V respectively Cell The replaceable battery pack 26 is constructed so that it can be removably inserted into the Figure 2 The embodiment shown in FIG. 1 is an electrical load 10 in the form of a multifunctional tool 24 .

[0053] The replaceable battery pack 26 has an electrical contact 32 of the electromechanical interface 28 at one end, which includes two electrical contacts 34 configured as power supply contacts 36 and three further electrical contacts 34 configured as signal or data contacts 38. On the one hand, the electrical load 10 or the multi-function tool 24 can be supplied with energy via the power supply contacts 36. On the other hand, the replaceable battery pack 26 can also be charged by means of a charger (not shown). Information about various operating parameters of the replaceable battery pack 26, such as the battery voltage U , can be transmitted to the electrical load 10 or the charger via the signal or data contacts 38. Batt , cell voltage U Cell, the temperature T measured in the replaceable battery pack 26, the charging or discharging current I, the coding, etc., for evaluation there. The electronic components of the electrical appliance 10 or the charger can control or regulate the discharge or charging process according to these operating parameters.

[0054] A mechanical contact 40 is arranged at the end of the replaceable battery pack 26 opposite the end of the electrical contact 32 with the electromechanical interface 28, for mechanically connecting the replaceable battery pack 26 to the electrical load 10 in a tool-free, detachable manner. The mechanical contact 40 comprises two elastic latching projections 42, which can be connected to the housing 14 of the electrical load 10 in a force-locking and form-locking manner. Usually, a corresponding latching is not required in the charger, so that the latching projections 42 are not used there. However, it is also conceivable that the replaceable battery pack 26 is locked in the charger during the charging process.

[0055] exist Figure 4 The battery voltage U is 18V. Batt In the housing 14 of the replaceable battery pack 26, ten cylindrical energy storage cells 20 are arranged in two layers. Two energy storage cells 20 are connected in parallel to form a cell cluster. Then, a total of five cell clusters are connected in series, so that the cell voltage U is 3.6V. Cell The total battery voltage U is 18V Batt . A charge status display 44 is arranged on the outer surface of the housing 14 of the replaceable battery pack 26, by which the charge status can be displayed. The electromechanical interface 28 of the replaceable battery pack 26 has two guide rails 46, which are guided when inserted into corresponding guide grooves of the electromechanical interface 30 of the electrical consumer 10 or the charger. In addition, a locking element 48 is provided, which is configured to lock the replaceable battery pack 26 on the electrical consumer 10. The locking element 48 is configured as a pivotable and elastically supported latching device, which locks automatically at the end of the insertion process. Unlocking of the inserted replaceable battery pack 26 can be achieved by operating a mechanical operating element (not shown), which is arranged on the side of the replaceable battery pack 26 opposite to the charge status display 44. The electrical contact 32 of the electromechanical interface 28 is arranged between the two guide rails 46 and has a plurality of electrical contacts 34 for locking according to the state of charge. Figure 3 The replaceable battery pack 26 shown carries out energy and data transmission. Here, the signal or data contact 38 is especially designed as a coil, which inductively transmits operating parameters to the electrical load 10. Therefore, the electrical contact 34 should also be understood as a contact that enables contactless energy and / or data transmission.

[0056] Figure 5a Shown in Figure 3The interior of the replaceable battery pack 26 shown in FIG. 2 before its assembly. The replaceable battery pack 26 comprises three lithium-ion energy storage cells 20, which are arranged in such a way that their cross section has a substantially triangular outer contour (see also FIG. 2 ). Figure 8 ). Each energy storage cell 20 itself has a positive battery pole and a negative battery pole 50 on its end side. Figure 5b 2 shows the replaceable battery pack 26 after the internal components are assembled. Figure 3 In contrast, the electrical contact 32 of the electromechanical interface 28 has only two signal or data contacts 38 instead of three. The three energy storage cells 20 are connected in series by means of two cell connectors 52 so that with a cell voltage U of 3.6 V each, the three energy storage cells 20 are connected in series. Cell The battery voltage U is 10.8V. Batt .

[0057] Each cell connector 52 is configured as a flat stamped sheet metal. Figure 6 On the one hand, the first end 54 is electrically connected to the electrical connection point 56 of the circuit board 58 by means of material locking, for example by means of soldering. Subsequently, the circuit board 58 and its electrical connection points 56 and the end 54 of the cell connector 52 are cast in a casting material 60, in particular completely. The casting material 60 can, for example, consist of a low-pressure molding thermoplastic. During low-pressure molding, the circuit board 58 and its electrical connection points 56 are placed in a concave casting mold and then filled with a hot viscous polymer. After the polymer cools, a robust and partially elastic shell is formed, which ensures very good protection against corrosion caused by moisture, fingerprints, etc. Alternatively, it is also conceivable that the casting material 60 consists of a silicone material. Figure 6 The printed circuit board 58 with its electrical connection points 56 and the ends 54 of the cell connectors 52 are shown in a side sectional view after being potted with potting compound 60 , wherein the potting compound 60 is shown with dashed lines for a better visual representation of the internal structure.

[0058] In subsequent steps, Figure 5a and 5b In the embodiment, the cast circuit board 58 is arranged parallel to the longitudinal axis 62 of the energy storage cell 20. Figure 5b The cell connector 52, which is constructed as a flat stamped sheet or a stamped sheet, is connected by a cold welding method through corresponding contact points 64 (see also Figure 7 ) is connected to the battery pole 50 of the energy storage cell 20 by material locking.

[0059] The printed circuit board 58 can be electrically connected to at least one further printed circuit board 70 by means of a flexible line 66, in particular a multi-core flat ribbon cable 68, before being cast with the casting material 60, if necessary. In this case, the further printed circuit board 70 is connected in particular to two further stamped sheets 72, which are used to electrically connect the positive battery pole 50 of the first energy storage cell 20 connected in series and the negative battery pole 50 of the last energy storage cell 20 to the positive or negative energy supply contact 36 of the electromechanical interface 28. The two energy supply contacts 36 are directly soldered to the further printed circuit board 70, but can also be electrically connected to corresponding cables. The corresponding situation applies to the further stamped sheet 72. After being cast with the casting material 60, the printed circuit board 58 and the at least one further printed circuit board 70 are finally arranged substantially perpendicular to each other around the energy storage cell 20.

[0060] At least one cell connector 52 has an SCM tap 74 for single cell monitoring (SCM), which is integrally connected to the cell connector 52 and is preferably arranged between the end 54 for electrical contact with the circuit board 58 and the contact point 64 for electrical contact with the battery pole 50 of the energy storage cell 20. The SCM tap 74 is materially connected to a cable (not shown) such as by welding, which itself is connected to the SCM upstream stage (not shown) of the corresponding electronic device, if according to Figure 1 If the load 10 has a fixed integrated battery pack 18, the electronics are arranged either in the replaceable battery pack 26 or in the load 10. Cell The SCM front stage switches between the various SCM taps 74 of the cell connector 52 in such a sequence, for example, by means of an integrated transistor, so that they are respectively connected to a positive battery pole and a negative battery pole 50 of the energy storage cell 20 to be measured. Here, the term "energy storage cell" should also include a cell cluster, because the cell cluster only has an impact on the capacity of the replaceable battery pack 10, but is not useful for detecting the cell voltage U Cell are equivalent.

[0061] The electronic device of the replaceable battery pack 26 or the electrical appliance 10 can have an integrated circuit in the form of a microprocessor, an application-specific integrated circuit (ASIC), a digital signal processor (DSP) or the like for controlling or regulating the charging or discharging process. It is also conceivable that the control or regulation is realized by means of a plurality of microprocessors or at least partially by means of discrete components with corresponding transistor logic. In addition, the electronic device can have a memory for storing operating parameters. Since such electronic devices are known to those skilled in the art, no further discussion will be given for this.

[0062] exist Figure 7One of the cell connectors 52 is shown in detail in FIG. The cell connector has at least one tolerance compensation structure 76 for adapting to the length L of the energy storage cell 20 (see Figure 5a and 5b ). Here, the tolerance compensation structure 76 of the cell connector 52 is configured as a U-shaped fold 78 parallel to the longitudinal axis 62 of each energy storage cell 20, wherein the orientation of the fold 78 can be configured differently according to the spatial conditions and the material thickness of the stamped sheet. Instead of the U-shaped fold, a zigzag or wavy fold can also be considered. Because the electrical connection between the cell connector 52 and the circuit board 58 is completed when the circuit board is equipped and each component has a fixed length, the tolerance compensation structure 76 is used to compensate for possible length tolerances of the energy storage cell 20, the circuit board 58 and / or their connection parts 54, 56.

[0063] Figure 8 A cross section of a replaceable battery pack 26 through three energy storage cells 20 arranged in a triangle and surrounded by the housing 14 of the replaceable battery pack 26 is shown. The cross section shown is located approximately at the height of half the length L of the energy storage cell 20 (see FIG. 5 ). In order to keep the design of the replaceable battery pack 26 as compact as possible, the printed circuit board 58 surrounded by the potting compound 60 is arranged on two adjacent energy storage cells 20 in such a way that it does not extend beyond the envelope 80 formed by the energy storage cells 20 in the cross section.

[0064] By means of a first temperature sensor 82, which is preferably designed as a negative temperature coefficient thermistor (NTC) and is arranged in the form of a surface mount device (SMD) on a circuit board layer 84 of the circuit board 58, the temperature T of at least one energy storage cell 20 can be measured and evaluated by the replaceable battery pack 26 or the electronics of the consumer 10 or the charger. For this purpose, the first temperature sensor 82 is in as close thermal contact as possible with the energy storage cell 20. In addition, the first temperature sensor is electrically connected to the signal or data contact 38 of the electromechanical interface 28 for transmitting the detected temperature T. In the case of a fixed integration of the battery pack 18 into the consumer 10, the first temperature sensor 82 can also be directly connected to the electronics of the consumer 10. The circuit board 58 and the first temperature sensor 82 are particularly completely surrounded by the potting material 60. In order to connect the temperature sensor 82 to the energy storage cell 20 in a particularly good thermal manner, the potting material 60 is designed to be heat-conductive and is in thermal contact with the energy storage cell 20, in particular, at the location of the temperature sensor 82.

[0065] In addition to the first temperature sensor 82, a further temperature sensor 86 is arranged on the printed circuit board 58, which is spaced apart from the first temperature sensor 82 so that it detects the temperature T of the further energy storage cell 20. The further temperature sensor 86 is surrounded by a heat-conductive potting compound 60 corresponding to the first temperature sensor 82, so that the potting compound is in the best possible thermal contact with the further energy storage cell 20, in particular at the location of the further temperature sensor 86. Thus, both energy storage cells 30 can be monitored in the sense of hot single-cell monitoring and, if necessary, individually deactivated by corresponding switching elements on the printed circuit board 58, for example by an SCM upstream stage, when a predetermined temperature limit value is exceeded or fallen below.

[0066] In order to optimize the thermal conductivity between the temperature sensors 82, 86 and the energy storage cell 20, the thermal contact surface 88 of the heat-conductive casting material 60 is adapted to the outer contour 90 of the energy storage cell 20. In the present embodiment, the energy storage cell 20 is configured as a cylindrical round battery. Therefore, when the thermal contact surface 88 of the heat-conductive casting material 60 has a concave shape complementary to this so as to form a surface as large as possible, an optimized thermal conductivity is obtained, which conducts the temperature T of the energy storage cell 20 to the temperature sensors 82, 86. In addition, this form-locking allows for simplified assembly of the cast circuit board 58, because the corresponding preformed casting material 60 causes repeatable positioning on the energy storage cell 20. As mentioned at the beginning, other shapes of energy storage cells 20 can also be considered. Accordingly, the thermal contact surface 88 of the heat-conductive casting material 60 should be configured complementary thereto.

[0067] according to Fig. 9 , on the side of the printed circuit board 58 opposite the printed circuit board layer 84, in the region of the temperature sensors 82, 86, recesses 92 are respectively provided in the potting material 60. These recesses 92 are used in particular to achieve thermal isolation of the printed circuit board 58 or the temperature sensors 82, 86 from the replaceable battery pack 26 or the housing 14 of the electrical load 10. As a result, the thermal capacity in the vicinity of the temperature sensors 82, 86 can be reduced in order to avoid or at least reduce the temperature influence of other components and / or the replaceable battery pack 26 or the housing 14 of the electrical load 10 on the temperature sensors 82, 86. The recesses 92 are designed in such a way that a cavity is formed between the potting material 60 and the housing 14, which cavity limits the distance of the potting material 60 from the housing 14 at least in the region of the two temperature sensors 82, 86. As a result, damage to the temperature measurement due to temperature influences acting on the housing 14 can be further reduced or avoided.

[0068] In order to further reduce or avoid possible impairment of the temperature measurement due to temperature influences acting on the housing 14, the heat-conductive potting material 60 also has two protruding contact points 94 for the housing 14 of the replaceable storage battery pack 14 or the electrical load 10 on the side facing away from the energy storage cell 20 or the temperature sensors 82, 86, in order to form an air gap between the housing 14 and the potting material 60. Preferably, the two temperature sensors 82, 86 are arranged substantially centrally between the two contact points 94, i.e., at a height of approximately half the length L of the energy storage cell 20 (refer to FIG. 1 ). Figure 5b ).

[0069] Figure 10 to Figure 1 3 shows a further exemplary embodiment for thermally coupling the temperature sensors 82, 86 to the energy storage cell 20 in order to achieve a high temperature detection accuracy by optimizing the thermal conductivity between the energy storage cell 20 and the temperature sensors 82, 86.

[0070] exist Fig.10 In the embodiment, the temperature sensor 82 for thermal coupling with the energy storage cell 20 is arranged directly on the circuit board layer 84 next to the side edge 96 of the circuit board 58. The circuit board 58 develops a circuit board plane 98, which is oriented perpendicular to the longitudinal axis 62 of the energy storage cell 20. Alternatively, it is also conceivable to arrange the temperature sensor 82 directly in the corresponding groove of the side edge 96. In addition, if the side edge 96 has a thermally conductive coating 100 at least around the temperature sensor 82, the thermal coupling can be improved. Similarly, refer to the previous FIG. 5 to FIG. Fig. 9 An embodiment can be considered in which the circuit board is completely surrounded by a heat-conducting potting material 60 in the area of ​​the side edge 96. Therefore, the heat generated during the charging or discharging process can be transferred from the energy storage cell 20 to the temperature sensor 82 in a targeted and low-loss manner. At the same time, since no separate assembly device or adhesive connection is required, a low-cost assembly is produced. The temperature sensor 82 is designed as a surface-mounted device (SMD) structural element, which is arranged on the circuit board layer 84 or directly in a not shown recess of the side edge 96. This allows a very small structural form and good point temperature measurement combined with simple mass production.

[0071] The side edge 96 is adapted to the outer contour 90 of the energy storage cell 20 in the area of ​​the temperature sensor 82. In the present embodiment, the energy storage cell 20 is configured as a cylindrical round battery. Therefore, when the side edge 96 of the circuit board 58 has a concave shape that is complementary thereto, an optimized thermal conductivity is obtained. As mentioned at the beginning, other shapes of the energy storage cell 20 are also conceivable. Accordingly, the side edge 96 should be configured to be complementary thereto.

[0072] By having at least one notch 102 around the temperature sensor 82 on the circuit board 58, a particularly good thermal contact between the temperature sensor 82 and the energy storage cell 20 can be additionally achieved. When the circuit board 58 is in the assembled state, the energy storage cell 20 deforms the notch 102 due to the corresponding pressure, so that the side edge 96 generates a spring force relative to the energy storage cell 20. In addition, it is conceivable that the side edge 96 itself is also deformed by being compressed by the energy storage cell 20 in the circuit board plane 98. In particular, when the notch 102 is surrounded by two areas of the circuit board 58 (not shown). By means of pressure and a spring force acting in opposition to the pressure, the temperature sensor 82 is always optimally held on the energy storage cell 20. In addition, the notch 102 can also cause thermal decoupling of at least one temperature sensor 82 from the rest of the circuit board 58. By using multiple notches 102 in the circuit board 58, the effect of the spring force and possible thermal isolation can also be enhanced. Figures 11a to 11d Four further variants for different numbers, arrangements and / or shapes of the recesses 102 are shown by way of example in FIG.

[0073] according to Fig.12 The circuit board 58 can also be configured in such a way that a further temperature sensor 86 is arranged on the other side edge 104 of the circuit board 58 for detecting the temperature T of the other energy storage cell 20. In this case, the further temperature sensor 86 is spaced apart from the first temperature sensor 82 so that it can detect the temperature T of the other energy storage cell 20 largely independently of the first energy storage cell 20. Thus, a plurality of energy storage cells 20 can be monitored in the sense of hot single cell monitoring and, if necessary, individually deactivated by corresponding switching elements on the circuit board 58 or by means of the electronics of the load 10 when a predetermined temperature limit is exceeded or fallen below. If the other side edge 104 has a heat-conducting coating 100 at least around the other temperature sensor 86, the thermal coupling can be improved similarly to the first side edge 96. In addition, a particularly good thermal contact between the temperature sensors 82, 86 and the energy storage cell 20 can be achieved by the circuit board 58 also having at least one notch 102 around the other temperature sensor 86, which works in a corresponding manner to the notch 102 for the first temperature sensor 82.

[0074] Instead of the side edges 96, 104 which lie flat on the outer contour 90 of the energy storage cell 20 to be monitored (see Fig.13a ), refer to Fig.13b and Fig.13c It is also conceivable that the side edges 96, 104 have one or two contact points 106 with the respective energy storage cell 20. In this way, an optimized thermal contact of the temperature sensors 82, 86 positioned on the side edges 96, 104 can be achieved depending on the radius of the outer contour 90 of the energy storage cell 20. Fig.13bThe single contact point 106 is particularly advantageous when the radius of the energy storage cell 20 is small, but according to Fig.13b The energy storage cell 20 with a larger radius can be better thermally connected via the two contact points 106 . Fig.13d A further possibility for thermal connection is shown, in which the side edges 96 or 104 are designed in a V-shaped manner and thus always have two defined contact points 106 for different radii or outer contours 90 of the energy storage cells 20 .

[0075] Finally, it should be pointed out again that the embodiments shown are not limited to Figure 1 to Figure 1 3, nor is it limited to the shape, number and size of the energy storage cells 20 shown therein. Accordingly, the number of temperature sensors may also be different. In addition, in addition to negative temperature coefficient thermistors (NTC), positive temperature coefficient thermistors (PTC) and other structural forms of temperature sensors may also be used. Likewise, the present invention is not limited to a circuit board 58 having only one circuit board layer 84, but can also be applied to so-called multi-layer circuit boards.

Claims

1. An energy storage unit (16) for an electrical appliance (10), the energy storage unit comprising at least one first energy storage cell (20), at least one first temperature sensor (82) for detecting a temperature (T) of the at least one first energy storage cell (20), and a circuit board (58) for receiving the at least one first temperature sensor (82), characterized in that: The at least one first temperature sensor (82) and the printed circuit board (58) are particularly completely surrounded by a heat-conducting potting material (60), wherein the heat-conducting potting material (60) is designed so that it is in thermal contact with the at least one first energy storage cell (20), particularly at the location of the at least one first temperature sensor (82).

2. The energy storage unit (16) according to claim 1, characterized in that The at least one first temperature sensor (82) is arranged on a circuit board layer (84) of the circuit board (58), and the potting material (60) has a recess (92) on a side of the circuit board (58) opposite to the circuit board layer (84) in the region of the at least one first temperature sensor (82), in particular for thermally isolating the circuit board (58) and / or the at least one first temperature sensor (82) from a housing (14) of the energy storage unit (16) or the electrical load (10).

3. The energy storage unit (16) according to claim 2, characterized in that: The recess (92) is designed such that a cavity is formed between the potting compound (60) and the housing (14), which cavity defines the distance between the potting compound (60) and the housing (14) at least in the region of the at least one first temperature sensor (82).

4. Energy storage unit (16) according to any one of the preceding claims, characterized in that Another temperature sensor (86) is arranged on the circuit board (58), and is spaced apart from the first temperature sensor (82) so that the other temperature sensor detects the temperature (T) of another energy storage cell (20), wherein the other temperature sensor (86) is surrounded by the potting material (60) so that the potting material is in thermal contact with the other energy storage cell (20), in particular at the location of the other temperature sensor (86).

5. Energy storage unit (16) according to any one of the preceding claims, characterized in that The thermal contact surface (88) of the potting material (60) is adapted to the outer contour (90) of the energy storage cell (20).

6. Energy storage unit (16) according to any one of the preceding claims, characterized in that The energy storage cell (20) is designed as a cylindrical round cell, and the thermal contact surface (88) of the potting compound (60) is designed complementary to the round cell, in particular concavely.

7. Energy storage unit (16) according to any one of the preceding claims, characterized in that The potting compound (60) has, on a side facing away from the at least one first energy storage cell (20), at least one protruding contact point (94) for the housing (14) of the energy storage unit (16) or the electrical load (10).

8. The energy storage unit (16) according to claim 7, characterized in that: The potting material (60) has two contact points (94), wherein the temperature sensor (82, 86) is arranged substantially centrally between the two contact points (94).

9. Energy storage unit (16) according to any one of the preceding claims, characterized in that The potting compound (60) is designed as an elastic thermoplastic.

10. Energy storage unit (16) according to any one of the preceding claims, characterized in that A printed circuit board (58) surrounded by the potting material (60) is arranged on two adjacent energy storage cells (20) such that the printed circuit board does not protrude beyond an envelope (80) formed by the two energy storage cells (20) in cross section.

11. An electrical load (10) having an energy storage unit (16) according to any one of the preceding claims.

12. A system comprising an electrical load (10) designed as a handheld power tool (24) and at least one energy storage unit (16) designed as a replaceable rechargeable battery pack (26).

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