CH708116B1 - Mobile electrical device with at least two lithium-ion batteries and arrangement of two such electrically connected in series accumulators. - Google Patents

Abstract

The invention relates to a mobile electrical device (10), in particular a hand tool (12) or hand-held garden tool, with an electrically driven drive motor (14) for rotating, oscillating and / or rotating tool carrier (16) or machining tools (18), the electrical power supply (20) comprises at least two electrically connected in series lithium-ion batteries (22) of the same type and substantially the same capacity and rated voltage. The accumulators (22) are each assigned separately operating monitoring devices (24) for the permanent monitoring of electrical and / or physical parameters such as actual voltages, current strengths and / or temperatures at the individual accumulators (22). The monitoring devices (24) are coupled to a protection circuit (26) which, at least when undervoltages and / or overtemperatures occur, limit voltage and / or current limitation and / or disconnect the affected accumulator (22) or the affected accumulators (22) from others provide electrical components of the electrical device (10).

Description

The present invention relates to a mobile electrical device, in particular a hand tool or garden tool o. The like. With electrically operated drive motor for rotating, oscillating and / or rotating tool carrier or processing tools, the electrical power supply at least two electrically connected in series Li-thium ion accumulators of the same type and largely the same capacity and rated voltage includes. The invention further relates to an arrangement with at least two electrically connected in series lithium-ion batteries of the same type and largely the same capacity and rated voltage, in particular for the electrical power supply of a mobile electrical device such as a hand tool, a garden tool or the like.

Mobile electrical devices with batteries that can be operated independently of the power supply, have long been known. With the increasingly higher energy density and the falling costs of modern accumulators not only portable computing devices, but also, for example, hand tools, gardening equipment or other devices are equipped with batteries so that they are independent of a public power grid to power and thus without disturbing cables for longer Periods can be used and operated at almost any location.

As accumulators with sufficiently high energy density in particular so-called. Lithium-ion accumulators are used. Such lithium-ion batteries not only have a relatively high energy density, but they are thermally stable and subject to only a very small memory effect, whereby they can keep a sufficiently high capacity available even with little careful charging behavior. Depending on the type of accumulator used, these may have different operating parameters, for example different cell voltages, temperature sensitivities or maximum permissible charging or discharging currents.

Despite their wide range of applications and their universal replaceability is a long life of the lithium-ion batteries, however, requires their careful treatment. The so-called cycle life depends on the type and quality of the battery, the temperature, and the type of use of the battery, in particular the (discharge) loading strokes, the end-of-charge voltage and the strength of the charging and discharging currents. At high temperatures, the cycle life can be significantly reduced, which is why the battery should be used best at room temperature. Low temperatures during operation can also damage the batteries, while storage at low temperatures usually causes no problems. Loading and unloading with relatively flat charging curves can significantly increase the durability. For example, a lithium-ion battery, from which instead of 100% only 50% of the maximum capacity can be discharged and then recharged, can withstand more than twice the number of cycles. The reason for this is that when fully discharged and fully charged battery high loads for the electrodes. Likewise, high charge and discharge currents increase the mechanical and thermal loads and thus have a negative effect on the number of cycles.

In a mobile use in electrical appliances, many of the risks mentioned can occur, which can reduce the life of the accumulators used as an electrical energy supply. This is especially true when used in hand tools, as this can occur more often unfavorable operating conditions, so for example, relatively high or low temperatures, voltage spikes or more frequent deep discharges by a robust use of hand tools, eg. On construction sites or in the field of outdoor installations. For this reason, the reliability of the accumulators should be given increased attention in such conditions of use.

The primary object of the present invention is seen to provide a particularly reliable and durable mobile electrical device, in particular a hand tool with electrically operated drive motor for rotating, oscillating and / or rotating tool carrier or machining tools, available, the electrical power supply at least comprises two electrically connected in series lithium-ion batteries of the same type and largely the same capacity and rated voltage. In this electrical device, in particular, the electrical power supply should be as well protected and protected against damage of all kinds by improper treatment and / or by particularly harsh operating conditions, which should be realized primarily by a suitably designed monitoring circuit.

These stated objects of the invention are achieved by the subject matters of the independent claims. Further advantageous embodiments of the invention can be found in the subclaims. Thus, the invention proposes to solve the above problem, a mobile electrical device, which may be in particular a hand tool with electrically operated drive motor for rotating, oscillating and / or rotating tool carrier or processing tools. The electrical power supply of the electrical device or the hand tool comprises at least two electrically connected in series lithium ion batteries of the same type and largely the same capacity and rated voltage, each separately operating monitoring devices for permanent monitoring electrical and / or physical parameters such as current voltages, currents and / or temperatures are assigned to the individual accumulators, which in turn are coupled to a protective circuit which, at least when occurring undervoltages and / or excess temperatures, a voltage and / or current limitation and / or a separation of the affected accumulator or affected accumulators of other electrical Provide components of the electrical device. In addition, other parameters can be monitored and used to control the Akkumula factors that can have an impact on the function and / or life of the batteries. Such additional parameters may be, in particular, a current consumption or an under temperature.

In addition, the protection circuits can provide that voltage and / or current limiting are provided even in the event of overvoltages and / or under-temperatures, optionally also a separation of the affected accumulator or the affected batteries of other electrical components of the electrical device can be provided , While overvoltages can occur in particular during charging processes and can lead to problems here, undervoltages can lead to serious problems and damage to the accumulators, especially during operation of the device. Occurring overvoltages can be secured by appropriate precautions in the charger normally, while under-voltages that occur in operation, either by a suitable protection circuit in the device and / or by a corresponding protection circuit in the accumulator are hedged.

In the inventive electrical device, in particular two identical and electrically connected in series lithium-ion batteries can be installed, which are arranged in a common housing compartment of the electrical device or spatially separated from each other in each separate housing compartments of the device. It makes sense to the accumulators can be removed for maintenance purposes without the aid of tools from their housing compartments and used there again. The location of the batteries in the device, i. the arrangement of the corresponding housing compartments for receiving the batteries depends on the space available or according to the available installation space or optionally according to specifications of a weight balance of the device, which, for example, may be of importance in hand tools, since a meaningful weight distribution usually ergonomic advantages brings, while an unfavorable weight distribution can lead to a faster fatigue of the user, since this unnecessarily high holding forces can occur.

The monitoring devices of the inventive electrical device, according to an advantageous embodiment, each protection circuits for detecting electrical short circuits in a detected overshoot of a maximum allowable current to the affected battery or to the series-connected accumulators and the separation of the affected accumulator or affected accumulators Provide additional electrical components of the electrical device. In this way, the batteries can be protected from damage caused by excessive current or by an electrical short circuit. In addition, the protective circuits may preferably also each have means for at least temporary current limiting in a detected overshoot of the maximum permissible defined current.

A variant of the inventive electrical device provides that its monitoring devices each have protective circuits, which are assigned to each individual battery and provide a separation of the affected accumulator or the affected accumulators of other electrical components of the electrical device, as soon as a protective circuit at least one Accumulator responds. It is provided that each of a plurality of accumulators each have a protective circuit is assigned, each autonomously monitors the parameters of its associated accumulator and / or ensures its electrical isolation from the device as soon as a fault and / or malfunction was detected. In other words, the protective electronics for securing the batteries and their operational reliability are always technically and physically arranged on the battery itself, so that they can be protected and protected under all circumstances, regardless of their state of charge. The protection electronics associated with the individual batteries can provide the required protection even with a half-empty or a relatively old battery, even if this is possibly combined with a new battery. A typical problem that can occur here is the faster discharge of old batteries and / or their faster voltage drop. The protective circuits assigned to the individual batteries can even protect this case. On the other hand, if only protection electronics were present in the device but not in the battery, this could lead to many problems, e.g. when using an improper or incorrect charger. By contrast, the batteries insured according to the invention can be used in any third-party devices, without any risks being associated with the service life of the batteries.

A further variant of the electrical device according to the invention can provide that the protective circuits provide an at least temporary electrical separation of the drive motor and / or other electrical consumers of the accumulators at a detected overshoot of the maximum allowable defined current. In addition, it can preferably be provided that the protective circuits provide an at least temporary electrical separation of the drive motor and / or other electrical consumers of the accumulators in a detected over or Unterschrei-tion of the maximum permissible voltage defined.

Thus, the monitoring devices can each protection circuits for detection and detection of electrical surges when exceeding a maximum allowable voltage and / or excessive current to the affected accumulator or to the series-connected accumulators and the separation of the affected accumulator or affected accumulators Provide additional electrical components of the electrical device. Preferably, in this variant, the protective circuits each have means for limiting the voltage at a detected excess of the maximum permissible voltage defined on the accumulators. In this case, the protective circuits can provide an at least temporary electrical separation of the drive motor and / or further electrical load from the battery mulatoren at a detected overshoot of the maximum permissible defined voltage, which in turn avoiding damage to the batteries and / or associated with these electrical control circuits can serve.

In addition, the protection circuits preferably each have means for limiting the voltage or current limit and / or for deactivating the batteries at a detected undervoltage of the batteries, i. when falling below the minimum required voltages defined on the accumulators. In this case, the protective circuits can provide an at least temporary electrical separation of the drive motor and / or further electrical load from the accumulators, which in turn can serve to avoid damage to the accumulators and / or connected to these electrical control circuits at a detected shortfall of the minimum necessary voltages. Under-voltages can lead directly to decomposition phenomena at the cathodes of the accumulators and to the dissolution of the metal oxide and metallic electrode carriers. Since undervoltages that occur in the operation of the batteries, the cells are overwhelmed or at the end of a charge cycle, it is necessary to provide for these cases, a shutdown and disconnection of the electrical connections between the batteries and the consumers of the electrical device.

Optionally, the protective circuits may also each have means for limiting the current at a detected overshoot of the maximum allowable defined current to the accumulators. In this case, the protective circuits can provide an at least temporary electrical separation of the drive motor and / or other electrical loads from the accumulators when a detected exceeding the maximum allowable defined current, which in turn serve to avoid damage to the accumulators and / or associated with these electrical control circuits can.

Optionally, the electrical device may also be provided with monitoring devices, each protective circuits for detecting excess temperatures when exceeding a maximum allowable temperature on the affected accumulator or to the series-connected accumulators and the separation of the affected accumulator or the affected accumulators of others provide electrical components of the electrical device. Another useful variant of the electrical device provides that its monitoring devices each protection circuits for detecting under-temperatures when falling below a minimum allowable temperature at the affected battery or to the series-connected accumulators, in particular of temperatures below 0 ° C, and to separate the affected Provide accumulator or the affected accumulators of other electrical components of the electrical device. Since the lithium-ion batteries used in the electrical device according to the invention typically react sensitively to under-temperatures, in particular to temperatures below about 0.degree. C., it may be sensible to operate at such temperature ranges by switching off or deactivating the rechargeable batteries or batteries to prevent their control electronics, so that the batteries are not permanently damaged by prolonged operation at too low temperatures.

In the variants of the electrical device, which are equipped with such a monitoring of the temperature ranges, a timed reactivation of electrical components and / or the electric drive motor may be provided, provided that the detected temperature of the accumulators after a defined period of time within a certain range lies. In this way it is prevented that the user is prevented in a no longer given risk of damage to the batteries on the further intended use of the inventive electrical device.

Alternatively or additionally, in the electrical device, however, also be provided that for re-release of the batteries and / or their electrical connection with other components of the device and / or with the electric drive motor after disconnection or shutdown an acknowledgment via an additional Pushbutton or switch is required. In addition, in the interest of increased user friendliness, an additional optical display or a signaling device or the like may be advantageous. Thus, for example, a temporary or can only be canceled by active release separation of the batteries of other components of the device and / or the electric drive motor via at least one optical display or signaling device be identified.

In the inventive electrical device, the lithium-ion batteries, for example, each having a nominal voltage between about 12 and about 25 volts, with electrical hand tools in particular rated voltages of about 18 V each are useful and practical. It can be provided that the lithium-ion accumulators each have an overvoltage resistance of up to 45 volts, in particular of up to 60 volts. In addition, lithium-ion batteries with nominal capacities of about 1 to 5 ampere hours have proven to be practicable, with typical electric hand tools in particular batteries with nominal capacities between about 1.5 and 3 ampere hours can be used.

The present invention further relates to an arrangement with at least two electrically connected in series lithium-ion batteries of the same type and largely the same capacity and rated voltage, in particular the electrical power supply of a mobile electrical device such as a hand tool with electrically driven drive motor for rotating, oscillating and / or rotating tool carrier or machining tools can serve. Here, the at least two lithium-ion batteries each separately operating monitoring devices for permanent monitoring of electrical and / or physical parameters such as current voltages, currents and / or temperatures can be assigned to the individual accumulators, with a

Protection circuit are coupled, which provide at least for overvoltages occurring and / or excess temperatures, a voltage limit and / or a separation of the affected accumulator or the affected accumulators of other electrical components of the electrical device. Further variants of this arrangement according to the invention may have features as explained above with reference to various embodiments of the electrical device according to the invention. These device variants relate equally to different embodiments of the arrangement of two electrically connected in series lithium-ion batteries.

Another, in practice very advantageous function of the inventive accumulators may consist in that they have a kind of stair-step-shaped switching system, whereby each same batteries can be used in different devices, e.g. This can be achieved by adapting the protection and control electronics assigned to the batteries to the respective devices and ensuring that the batteries are protected and protected in a wide variety of operating situations. The term staircase-shaped switching system means in particular that, depending on the battery cells used, different currents can be permitted, some of which may flow only for a very short period of time (quasi-stationary operation). Since the universal batteries used are not previously known in which devices they are used and which power profiles can occur there, the control concept provides that in each case a defined continuous current for a defined maximum period of time is allowed, which depends on the cell. For example, a current between 30 and 60 amperes may be allowed for a maximum period of one to 1.5 seconds. A higher current of, for example, 60 to 90 amps can thus be used for a shorter period of time, e.g. 150 milliseconds, while higher currents of e.g. above 100 amps only for a maximum period of time, e.g. two milliseconds are allowed. This switching characteristic, referred to here as a step-step characteristic, makes it possible to use the batteries in a wide variety of devices without it being necessary to first know what the exact consumption and requirement profile of the devices looks like. The maxim, which is not violated here at any time, is that the accumulator modules themselves ensure that their cells are not overwhelmed at any time, so that so a large variety of different devices can be operated equally. Another advantage is that it eliminates the need for elaborate protocols, production and / or operating protocols that would otherwise be essential for smooth communication between the devices and the batteries, otherwise there is a risk of damaging or damaging the batteries due to certain operating conditions destroy that are not secured.

For those skilled in the art, it goes without saying that these specified values for the step-like protection and protection characteristics are merely exemplary and depending on the capacity of the battery, their specific properties, the ambient and / or operating conditions and the typically occurring load cases different devices can vary.

The electrical device may optionally have two lithium-ion batteries with a total rated voltage of about 36 volts or three lithium-ion batteries with a total nominal voltage of about 54 volts. Upwards, these values are possibly expandable, as well as devices with four or more similar accumulators are conceivable, for example. Mobile welding devices o. The like., Which have a higher power consumption and higher voltages (eg ultrasonic welding device) for a meaningful substitution need ,

If necessary Individual devices can be supplemented by additional capacitors or coils. Thus, a further embodiment variant of the electrical device according to the invention provides that the accumulators are assigned at least one capacitor module and / or a coil set for briefly increasing the retrievable current intensity when load peaks of the device occur. In this way, the capacity can be increased in the short term advantageously at very low additional cost, which may, for example, be advantageous for a delivery torque of an electric drive motor, which may have a higher power consumption at high loads occurring at short notice.

In addition, it should be mentioned that even individual batteries, as described above, are used in devices and can be quickly replaced there as needed. Due to the configuration according to the invention with the protection circuit associated with the individual battery, it is no problem in practice to use and replace batteries which do not have their full state of charge since their protection circuit protects them from deep discharge, under and over temperature and other operating conditions And beyond that, it can safeguard all sorts of conceivable malfunctions.

Another advantageous aspect, which has not yet been mentioned, is that with the help of the accumulators targeted influence on the ergonomics and manageability of portable electrical equipment can be influenced, as depending on the placement and positioning of the batteries in the device different weight distributions can be achieved so that the weight balance ideally for optimal ergonomics already in the construction of the device can be achieved. This can affect a wide variety of hand tools, but also for all types of portable gardening tools and other portable tools application, eg. For hedge trimmers, chainsaws, etc.

Moreover, it is useful to provide suitable protective elements in the inventive electrical device, in particular for a suitable ESD protection, i. E. to provide protection against damage due to electrostatic discharge. Thus, it is advantageous if at least one of the at least two batteries connected in series has a bidirectional diode (Diac) connected in parallel. Of course, it is even more advantageous if each of the at least two series-connected accumulators in each case a bidirectional diode (Diac) is switched in parallel. In addition, the electric load, in particular the electric drive motor of the device, a freewheeling diode may be connected in parallel. Thus, within the two battery packs, each of the two accumulators can each have a bidirectional diode, a so-called diac, connected in parallel. These diacs ensure that in unequally charged batteries or accumulators with very different electrical values or capacities no unwanted discharge effects, but at the same time when exceeding the breakdown voltages, the protection electronics is relieved by the bypass, which corresponds to an effective ESD protection. Thus, the diacs connected in parallel ensure that the power supply to the motor is interrupted if one of the rechargeable batteries or rechargeable battery packs does not work properly, while the other one is already there to prevent discharge or damage to the properly functioning rechargeable battery in such situations. In addition, it makes sense to connect a freewheeling diode in parallel to the motor or the electrical load, which can provide protection of the power supply consisting of the battery or the two series-connected battery packs when voltage spikes occur on the motor.

To clarify, it should be noted that the term "accumulator" commonly used in the present context normally designates the ready-to-install and exchangeable battery module or battery pack, but not the individual cell of such a module. That is, when the term "accumulator" is used in the present context, it usually means the battery module or battery pack.

In the following, embodiments of the invention and their advantages are explained in more detail with reference to the accompanying figures. The size ratios of the individual elements to one another in the figures do not always correspond to the actual size ratios, since some shapes are simplified and other shapes are shown enlarged in relation to other elements for better illustration.

Fig. 1 shows a schematic representation of an embodiment of an inventive electric machine having an electric drive motor whose electrical power supply has two series-connected lithium-ion batteries.

FIG. 2 shows a schematic plan view of an electric lawn mower as an application example of the electrical device according to the invention.

FIG. 3 shows a schematic perspective view of the electric lawnmower according to FIG. 2.

Fig. 4a shows a schematic perspective view of an embodiment of an accumulator, as it can be used in Ra sen mower according to FIG. 2 and FIG. 3 or in an electrical device according to FIG. 1.

4b shows in an enlarged plan view a contact region of the battery according to FIG. 4a.

FIG. 5 shows a schematic block diagram of an electrical power supply of the device according to FIG. 1 or of the lawnmower according to FIG. 2 and FIG. 3.

6 shows a block diagram to illustrate various functionalities of the electrical power supply according to FIG. 5.

Fig. 7 shows a perspective view of an electric chain saw as an embodiment of a battery-powered, portable gardening tool or garden tool.

Fig. 8 shows in two perspective views of a cordless drill or cordless screwdriver with a removable battery on its housing bottom.

9 shows in two circuit diagrams (FIGS. 9a and 9b) the connection of the battery packs with additional protective devices to ensure ESD protection.

For identical or equivalent elements of the invention, identical reference numerals are used. Furthermore, for the sake of clarity, only reference symbols are shown in the individual figures, which are required for the description of the respective figure. The illustrated embodiments merely represent examples of how the device according to the invention or the method according to the invention can be configured and do not constitute a conclusive limitation.

The schematic representation of Fig. 1 shows a mobile electrical device 10, which may be formed in particular by a hand tool 12 with electrically operated drive motor 14 for rotating, oscillating and / or rotating tool carrier 16 or machining tools 18. The electrical power supply 20 of the drive motor 14 of the electrical device 10 includes in the illustrated embodiment, two electrically connected in series lithium-ion batteries 22 of the same type and largely the same capacity and rated voltage. The two lithium-ion batteries 22 are each assigned separately operating monitoring devices 24 for the permanent monitoring of electrical and / or physical parameters such as current voltages, currents and / or temperatures at the individual accumulators 22, which are coupled to a protection circuit 26, the at least in case of overvoltages and / or excess temperatures, a voltage limitation and / or a separation of the affected accumulator 22 or the affected accumulators 22 of other electrical components of the electrical device 10, in particular from the electric drive motor 14, provide. Preferably, the electrical device 10 and the hand tool 12, two identical electrically connected in series lithium-ion batteries 22, which are arranged in a common housing compartment 28 of the electrical device 10 or spatially separated from each other in each separate housing compartments of the device 10.

The schematic plan view of Fig. 2 shows a variant of the inventive mobile electrical device 10 in the form of a lawnmower 30, the electrically driven drive motor 14 drives a not recognizable here rotating knife on its underside. The electrical power supply 20 of the drive motor 14 is effected by two lithium-ion accumulators 22 of the same type, identical capacitance and rated voltage connected in series. The battery 22 associated monitoring devices 24, which are each coupled to protection circuits 26 may, for example, be arranged above the motor 14, as indicated in FIG. 2. As can also be seen from FIG. 2, the batteries 22 are placed in a common housing compartment 28, which is located on a front side of the lawnmower 30. The easy accessibility of the batteries 22 placed in their housing compartment 28 is provided by a hinged housing cover 32 which, in the illustration of FIG. 3, is pivoted forward and thus opened. Optionally, the batteries 22 can be removed with the lid 32 open and disconnected from the device 10 or from the lawnmower 30.

The schematic perspective view of Fig. 4a shows an embodiment of one of the at least two provided for powering an electrical device 10 battery 22 (lithium-ion battery 22) having a cuboid battery housing 34 with top electrical connection contacts 36, the both sides of a slide-in frame 38 are flanked, so that insertion of the battery 22 at its intended location can only be done in the direction indicated by an arrow insertion direction 40. The electrical connection contacts 36 shown are arranged in parallel slots, so that a direct contact is excluded. The design of the electrical connection contacts 36 shown in FIG. 4 requires a corresponding design of the respective mating contacts in the housing compartment of the electrical device 10, so that an electrical contacting can be produced.

The plan view of Fig. 4b illustrates the arranged within the drawer frame 38 connecting contacts 36 at the top of the battery case 34 of the lithium-ion battery 22 (short: battery 22), which is not shown here with a corresponding contact strip in the region of the housing 28 such interaction that by the insertion of the battery 22 in the insertion direction 40, which points in the drawing direction of Fig. 4b to the right and parallel to the plane of the drawing, ie The connection contacts 36 comprise in the embodiment shown a total of five contact slots 42, of which, however, only three are occupied with metal pairs of contact springs 44, while two of the contact slots 42 due to the lack of contact springs not are prepared and capable of producing an electrical contact. Depending on the embodiment of the batteries 22, the total of five contact slots 42 of the connection contacts 36 can be occupied and activated as required in different ways.

4b, the contact slots 42 are each marked with different connection symbols 46 which each facilitate the occupation of the contact slots 42 and the correct electrical contact with the electrical device 10 (FIG. 1).

Fig. 4b also reveals two additional contacts, which are currently not used. From these additional contacts, for example, a contact can be used for newer devices to transmit an additional communication protocol for new devices. Thus, for example, certain specifications of the device are possible, which are transmitted to the battery 22, e.g. a power cut to protect a motor, a pulse current operation, etc., for example. For ultrasonic welding. However, these additional contacts can also be used for a permanent temperature query, a state of charge query o. The like., Which may also be done via this (optional) communication interface.

The schematic block diagram of Fig. 5 illustrates the electrical interconnection of the electrical power supply 20, which essentially comprises the two series-connected accumulators 22 - characterized by a battery pack 23 - and the drive motor 14, supplemented by the monitoring device 24 and the Protection circuit 26 for the monitoring and demand-based separation of the electrical connection between the battery pack 23 and the drive motor 14, this should be required to protect the battery 22. Thus, the monitoring device 24 monitor various parameters of the batteries 22 of the battery pack 23 and interrupt as required the electrical connection to the motor 14, for which the protection circuit 26 is responsible, preferably having electronic switching elements such as FETs or other suitable semiconductor switching elements.

Thus, the monitoring device 24 according to FIG. 5, for example. Protection circuits 26 for detecting electrical short circuits when exceeding a maximum allowable amperage on the affected accumulator 22 or to the series-connected accumulators 22 and the separation of the battery pack 23 of other electrical components of the electrical device 10 as in particular provide its drive motor 14. Optionally, the protection circuits 26 can each have devices for at least temporary current limitation in the case of an ascertained excess of the maximum permissible current intensity. It makes sense if the protective circuits 26 at ei ner detected exceeded the maximum allowable defined current strength at least temporary electrical separation of the drive motor 14 and / or other electrical loads of the accumulators 22, 23 provide.

In addition, the monitoring devices 24 of the electrical power supply 20 may each have protection circuits 26 for detecting and detecting electrical overvoltages, which detect an exceeding of a maximum allowable voltage to the affected accumulator 22 and to the series-connected accumulators 22 and the separation of the affected accumulator 22 or the affected accumulators 22 of other electrical components of the electrical device 10, in particular of its drive motor 14 provide. Furthermore, the protective circuits 26 may each have means for limiting the voltage when the excess voltage exceeds the maximum permissible voltage on the accumulators 22. Thus, the protective circuits 26 may provide an at least temporary electrical separation of the drive motor 14 and / or other electrical loads from the accumulators 22 at a detected overshoot of the maximum permissible voltage defined.

Another useful variant of the electrical power supply 20 of the electrical device provides that its monitoring devices 24 each have protective circuits 26 for detecting overtemperatures, when exceeding a maximum allowable temperature at the affected accumulator 22 and to the series-connected accumulators 22nd for a separation of the affected accumulator 22 or the affected accumulators 22 of other electrical components of the electrical device 10 and its drive motor 14 provide. Due to the peculiarities of the lithium-ion batteries 22 used, it may also be useful if the monitoring devices 24 each have protection circuits 26 for detecting low temperatures, which falls below a minimum allowable temperature on the affected accumulator 22 or to the series-connected accumulators 22, in particular of temperatures below 0 ° C, cause a separation of the affected accumulator 22 or the affected accumulators 22 of other electrical components of the electrical device 10, in particular a shutdown of the drive motor 14 to further consumption of electrical energy from the battery pack 23 prevent. Optionally, a temperature monitoring and a time-controlled re-activation of electrical components and / or the electric drive motor 14 may be provided, provided that the determined temperature of the accumulators 22 is within a certain range after a defined period of time.

The schematic representation of FIG. 6 shows, with reference to a block diagram, various functionalities of the electrical power supply 20 according to FIG. 5, in particular during a charging process. Thus, the monitoring device 24 (BMS - Battery Management System) either by activating a push button to query a state of charge (Push Battery LED Switch) or a push button to activate a device function (Push Application Button) or by activating a charger, eg. By the Wakeup of BMS or put into a standby state, after which the monitoring device 24 is initialized (initialization). After this initialization, the monitoring device 24 is initially active (BMS active), which also entails the activation of the corresponding semiconductor switching element, the FET (Discharge FET on). However, before this activation of the monitoring device 24 (BMS) takes place, a query is made by default as to whether an overvoltage and / or an excess temperature or too high a current level has been detected (current protection, voltage protection, temperature protection). If this is the case, the FET (Discharge FET off) is switched off, as well as if the charging temperature is too high (Temperature Protection - Discharge Temperature to high), too high a FET temperature (Current Protection - FET Temperature to high) or too high charging current (Discharge Current too high) or if a short circuit was detected (Short Circuit detected). Even if a too low cell voltage (voltage protection - cell voltage too low) or too large a difference of several cell voltages (voltage protection - cell voltage difference too big) is detected, such a shutdown of the monitoring device 24 (BMS active - Discharge FET off). Furthermore, such a shutdown of the monitoring device 24 (BMS active - Discharge FET off), if a cell voltage is detected, which is below 2.5 volts (Voltage below 2.5 V / Cell) or if over a period of more than three Hours no use has been made (3 h no use); both trigger a shutdown of the monitoring device 24 (BMS off - Discharge FET off). After such a shutdown, the activation in turn by pressing a push button to query a state of charge (Push Battery LED Switch) or a push button to activate a device function (Push Application Button) or by activating a charger, for example. By its connection to a power grid ( Plug in Charger to Charge) are activated (Wakeup of BMS).

The lithium-ion batteries 22 of the device 10 may each have a nominal voltage between about 12 and about 25 volts, in particular a nominal voltage of about 18 V, respectively. In addition, the batteries 22 of the device 10 may preferably each have an overvoltage resistance of up to 45 volts, in particular of up to 60 volts. Furthermore, the lithium-ion batteries 22 may each have a nominal capacity of about 1 to 5 ampere hours, in particular a nominal capacity of between about 1.5 and 3 ampere hours.

The schematic perspective view of Fig. 7 shows a chain saw 48, which acts as an example of an inventive electrical device 10 and a hand tool 12, such as the placement of the two lithium-ion batteries 22 on the housing for a favorable weight distribution can provide the device 10. In the illustrated embodiment, the two batteries 22 are next to each other in the vicinity of a rearwardly projecting handle 50, so that the center of mass of the device 10 between the rear handle 50 and a front handle strap 52 is located. The batteries 22 are each in slots in the immediate vicinity of an electric drive motor 54, which serves the drive of the rotating saw chain 56, which is guided on the Sägeschwert 58. The placement of the two batteries 22 on the back of the housing of the drive motor 54 and in the vicinity of the rear hand guide handle 50 can provide a favorable weight balance, so that the chainsaw 48 is ideally balanced and ergonomically designed particularly advantageous.

What is shown here with reference to the chainsaw 48, applies in principle equally for other portable garden tools in which such ergonomic design and a favorable weight distribution in the interest of comfortable and safe handling are important.

8 shows in two perspective views (FIGS. 8 a, 8 b) a cordless drill or cordless screwdriver 60 with an exchangeable battery 22 on its housing underside. The battery 22 has a structure and a design, as has already been shown in the two illustrations of Fig. 4a and Fig. 4b. FIGS. 8a and 8b illustrate, in particular, that individual accumulators 22, as described above, are also used in devices 10 and 12, respectively, where they can be quickly exchanged as needed. As a result of the configuration according to the invention with the protective circuit 26 assigned to the individual battery 22 (see FIG. 6), it is no problem in practice to use and exchange such batteries 22 in the short term that do not have their full charge state since the respective ones are assigned to them Protective circuit 26 protects them against deep discharge, under temperature and other operating conditions and beyond can protect all sorts of possible malfunctions.

9a shows an electrical circuit diagram of the electrical device 10, in which two accumulators 22 for the electrical power supply of an electric drive motor 14, for example. An electric hand tool 12, are connected in series. Within the two battery packs 22, bidirectional diodes 62, so-called diacs, are connected in parallel to each of the two accumulators 22, which ensure that unintentional discharge effects do not occur with unequally charged accumulators 22 or accumulators 22 with greatly different electrical values or capacities. Thus, the diacs 62 connected in parallel ensure that the power supply of the motor 14 is interrupted when one of the batteries 22 or battery packs 23 is not working properly, while the other one is already there to discharge or damage the properly operating battery 22 in such situations prevent. In addition, the Diacs 62 provide an effective ESD protection, since when the breakdown voltage is exceeded, the protection electronics of the battery pack 23 is reliably relieved by the bypass.

In addition, the circuit should be provided according to Fig. 9a with a freewheeling diode 64 as shown in FIG. 9b, which is connected in parallel to the motor 14 and at occurring voltage peaks on the motor 14 for protection of the power supply, consisting of the battery 22 and the two serially connected battery packs 23 (FIG. 9a) can provide.

For clarity, it should also be noted at this point again that the term "accumulator 22" commonly used in this context normally the ready-to-install and replaceable battery module or battery pack (denoted by reference numeral 23), but not the single cell of such a module , That is, when the term accumulator 22 is used in the present context, it usually means the battery module or battery pack 23.

The invention has been described with reference to a preferred embodiment. However, it is conceivable for a person skilled in the art that modifications or changes of the invention can be made within the scope of the following claims, without departing from the scope of the following claims.

REFERENCE NUMBER LIST 10 mobile electrical device, electrical device 12 hand tool 14 drive motor, electric drive motor 16 tool carrier 18 machining tool 20 electrical power supply 22 lithium-ion battery, lithium-ion battery, battery 23 battery pack 24 monitoring device 26 protection circuit 28 housing compartment

Claims (27)

30 Lawn mower 32 Housing cover 34 Battery housing 36 Connection contacts, electrical connection contacts 38 Insertion frame 40 Insertion direction 42 Contact slot 44 Contact spring 46 Connection symbol 48 Chainsaw 50 Handle, hand guide handle, rear handle 52 Handle, front handle 54 Electric drive motor 56 Saw chain 58 Saw blade 60 Cordless screwdriver 62 Bidirectional diode, bidirectional diode, Diac 64 freewheeling diode claims 1. Mobile electrical device (10), in particular hand tool (12), garden implement or hand-held garden tool, with electrically operated drive motor (14) for rotating, oscillating and / or rotating tool carrier (16) or processing tools (18), the electrical power supply (20 ) comprises at least two electrically connected in series lithium-ion batteries (22) of the same type and largely the same capacity and rated voltage, each separately operating monitoring devices (24) for permanent monitoring electrical and / or physical parameters such as current voltages, currents and / or Temperatures at the individual accumulators (22) are associated, which are coupled to a protective circuit (26), at least when occurring undervoltages and / or excess temperatures, a voltage and / or current limiting and / or a separation of the affected accumulator (22) or the affected accumulators (22) of provide additional electrical components of the electrical device (10). 2. Electrical device according to claim 1, the protective circuit (26) at least at overvoltages and / or under-temperatures a voltage and / or current limiting and / or separation of the affected accumulator (22) or the affected accumulators (22) of other electrical components of the electrical device (10) provide. 3. Electrical device according to claim 1 or 2, comprising two identical electrically connected in series lithium-ion batteries (22) in a common housing compartment (28) of the electrical device (10) or spatially separated from each other in separate housing compartments ( 28) of the device (10) are arranged. 4. Electrical device according to one of claims 1 to 3, the monitoring devices (24) each protective circuits (26) for detecting electrical short circuits when exceeding a maximum allowable current at the affected accumulator (22) or to the series-connected accumulators (22). and to provide for the separation of the affected accumulator (22) or the affected accumulators (22) of other electrical components of the electrical device (10). 5. Electrical device according to claim 4, whose monitoring devices (24) each have protection circuits (26) which are associated with each individual battery (22) and the separation of the affected accumulator (22) or the affected accumulators (22) of other electrical components of the electrical device (10) provide as soon as a protection circuit (26) of at least one accumulator (22) responds. 6. Electrical device according to one of claims 1 to 5, wherein each of a plurality of accumulators (22) each have a protective circuit (26) is assigned, each autonomously recognizes the parameters of its associated accumulator (22) and / or for the electrical Disconnection from the device (10) ensures as soon as an error and / or malfunction has been detected. 7. Electrical device according to one of claims 4 to 6, wherein the protective circuits (26) each having means for at least temporary current limiting at a detected overshoot of the maximum allowable defined current. 8. Electrical device according to one of claims 4 to 7, wherein the protective circuits (26) at a detected exceeding the maximum allowable defined current strength at least temporary electrical separation of the drive motor (14) and / or other electrical components of the accumulators (22 ). 9. Electrical device according to one of claims 1 to 8, whose monitoring devices (24) each protective circuits (26) for detecting and detecting electrical surges when exceeding a maximum allowable voltage on the affected accumulator (22) or to the series-connected accumulators ( 22) and to separate the affected accumulator (22) or the affected accumulators (22) of other electrical components of the electrical device (10) provide. 10. Electrical device according to claim 9, wherein the protective circuits (26) each have means for limiting the voltage at a detected overshoot of the maximum allowable defined voltage to the accumulators (22). 11. Electrical device according to claim 9 or 10, wherein the protective circuits (26) at an ascertained excess of the maximum permissible voltage defined at least temporary electrical separation of the drive motor (14) and / or further electrical components of the accumulators (22) provide , 12. Electrical device according to one of claims 1 to 11, the monitoring devices (24) each protective circuits (26) for detecting excess temperatures when exceeding a maximum allowable temperature on the affected accumulator (22) or to the series-connected accumulators (22) and provide for the separation of the affected accumulator (22) or the affected accumulators (22) of other electrical components of the electrical device (10). 13. Electrical device according to one of claims 1 to 11, whose monitoring devices (24) each protection circuits (26) for detecting under-temperatures when falling below a minimum allowable temperature at the affected accumulator (22) or to the series-connected accumulators (22), in particular of temperatures below 0 ° C, as well as for the separation of the affected accumulator (22) or the affected accumulators (22) of other electrical components of the electrical device (10) provide. 14. Electrical device according to claim 12 or 13, which provides a temperature monitoring and a timed reactivation of electrical components and / or the electric drive motor (14) provided that the detected temperature of the accumulators (22) after a defined period of time is within a certain range. 15. Electrical device according to one of claims 1 to 14, wherein the re-release of the accumulators (22) and / or their electrical connection with other components of the device (10) and / or with the electric drive motor (14) after a separation or Shutdown an acknowledgment via an additional pushbutton or switch is provided. 16. Electrical device according to one of claims 1 to 15, wherein a temporary or can only be canceled by active release separation of the batteries (22) of other components of the device (10) and / or the electric drive motor (14) via at least one optical display - or signaling device is recognizable. 17. Electrical device according to one of claims 1 to 16, the lithium-ion batteries (22) each having a nominal voltage between about 12 and about 25 volts, in particular a nominal voltage of about 18 V respectively. 18. Electrical device according to one of claims 1 to 17, which has two lithium-ion batteries (22) with a total rated voltage of about 36 volts. 19. Electrical device according to one of claims 1 to 17, the three lithium-ion batteries (22) having a total nominal voltage of about 54 V has. 20. Electrical device according to claim 17 to 19, the lithium-ion batteries (22) each have an overvoltage resistance of up to 45 volts, in particular each of up to 60 volts. 21. Electrical device according to one of claims 1 to 20, whose lithium-ion batteries (22) each have a nominal capacity of about 1 to 5 ampere hours, in particular a nominal capacity between about 1.5 and 3 ampere hours. 22. Electrical device according to one of claims 1 to 21, wherein the accumulators (22) at least one capacitor module and / or a coil set for briefly increasing the retrievable current at occurring load peaks of the device (10) are assigned. 23. Electrical device according to one of claims 1 to 22, wherein at least one of the at least two series-connected accumulators (22), a bidirectional diode, Diac, is connected in parallel. 24. Electrical device according to one of claims 1 to 23, wherein each of the at least two series-connected accumulators (22) in each case a bidirectional diode, Diac, is connected in parallel. 25. Electrical device according to claim 23 or 24, wherein the electrical component, in particular the electric drive motor (14) of the device (10) is connected in parallel with a freewheeling diode. 26. Arrangement with at least two electrically connected in series lithium-ion batteries (22) of the same type and largely the same capacity and rated voltage, the electrical power supply (20) of a mobile electrical device (10) such as a hand tool (12), gardening equipment or hand-held Garden tool, with electrically operated drive motor (14) for rotating, oscillating and / or rotating tool carrier (16) or processing tools (18), wherein the at least two lithium-ion batteries (22) each separately operating monitoring devices (24) for permanent monitoring electrical and / or physical parameters such as current voltages, currents and / or temperatures at the individual accumulators (22) are associated, which are coupled to a protective circuit (26), the at least when occurring over and / or under-voltages and / or excess temperatures a voltage limit and / or a separation of the affected A Provide accumulator (22) or the affected accumulators (22) of other electrical components of the electrical device (10). 27. Arrangement according to claim 26, for an electrical device (10) according to one of claims 2 to 25.