MACHINE TOOL AND BATTERY PACK FOR A MACHINE TOOL

Description

Disclosure of the invention

[0001] The present invention relates to a battery pack for a hand-held power tool according to claim 1 as well as a hand-held power tool according to claim 12 and a charger according to claim 14.

[0002] Electric hand tools are generally well-known and are powered by a mains connection. Alternatively, cordless tools offer a high degree of flexibility in working, as they are independent of mains power. This allows for convenient outdoor work, for example, so that battery packs are often used when operating a hand tool.

[0003] Such battery packs, see for example EP 1 637 897 A2, are generally known and usually have a plurality of rechargeable batteries connected in parallel and / or series, for example three cylindrical Li-ion cells connected in series, e.g. each with 3.6 V and a total voltage of 10.8 V. The connected battery cells must be connected to battery pack electronics on the one hand and to each other on the other. The battery pack usually comprises a battery pack housing in which the battery cells are either fully or partially accommodated, preferably by means of a cell holder. Alternatively, the cell holder itself forms a battery pack housing element of the battery pack housing.

[0004] For the purposes of this application, a battery pack is understood to mean a battery pack, preferably consisting of several electrically interconnected battery cells, which can store electrical energy that supplies the energy required to operate a handheld power tool and can be replaceably mounted in a chamber, an interface, or the like of the handheld power tool. In particular, an interface is understood to mean a device designed to establish an electrical and, if necessary, a mechanical connection with a charging device and / or a discharging side, i.e., the handheld power tool, directly or indirectly.

[0005] The battery pack is connected to the handheld power tool by plugging or pushing the battery pack interface into a complementary socket or interface on the tool housing. The interface has contact slots in which contact elements can be arranged. Once the battery pack has been used up, it can be removed and connected to a charging station with corresponding mating contact elements. If several battery packs are available, it is possible to remove the discharged battery pack from the handheld power tool and replace it with a charged one. The nominal voltage and capacity of the battery pack used generally determine the performance and runtime of the handheld power tools. It is therefore important that the tool and charger have information about the battery pack, such as the maximum charging and discharging current, as well as the current operating temperature and the internal resistance of the battery pack.

[0006] It is known from the prior art that different hand tools of a voltage class have battery packs that are incompatible with each other, whereas the battery packs of different hand tools within a voltage class, for example a straight screwdriver, a cordless drill, an impact drill, a jigsaw, a multi-function tool and / or a drill driver, are often compatible.

[0007] It is also known that battery packs can be identified to the charger and the handheld power tool using a code, so that other battery packs not intended for the handheld power tool, e.g., those with a different nominal voltage, are not accepted by the handheld power tool, to prevent damage to the battery pack and / or the handheld power tool. In other cases, the information transfer serves to optimize the interaction between the battery pack and the handheld power tool or charger.

[0008] In the prior art, this is achieved, for example, by signal contact elements arranged in the battery pack interface, via which battery pack-specific information can be transmitted to corresponding contact elements of the handheld power tool and / or charger. In some cases, information exchange between the battery pack and the handheld power tool and / or charger is also possible, meaning information can be transmitted in both directions.

[0009] In the prior art, the signal contact elements are usually connected to coding elements, such as coding resistors, on the battery pack side. A pull-up resistor is typically arranged in the corresponding mating contact elements of the handheld power tool and / or charger, via which voltage is supplied to the coding resistor on the battery pack side. A measuring circuit in the handheld power tool or charger then determines the resistance connected to the signal contact element, which is interpreted as battery pack-specific information by a corresponding control system of the handheld power tool or charger.

[0010] In battery pack electronics, a capacitor or a diode is often connected in parallel to the coding resistor as protection against electrostatic discharge (ESD).

[0011] In this context, it is fundamentally disadvantageous that, according to the coding element method described above, only a limited amount of information can be transmitted via a coding element. This is because both the battery packs and the handheld power tools and chargers, and thus the respective interfaces, are subject to constant development, which often makes it necessary to implement additional contact elements and counter-contact elements in the interfaces in order to exchange additional information between the devices. For reasons of handiness and manageability of both the battery pack and the handheld power tool, however, it is desirable to keep the installation space required for the interface as compact as possible. Furthermore, for reasons of compatibility with previous models, there may be a requirement to change the geometry of the interface as little as possible compared to a previous model.

[0012] The object of the invention is to remedy the aforementioned disadvantages and provide an improved battery pack of the type mentioned above, which can be used in a variety of different handheld power tools. The aim is to transmit as much information as possible via a battery pack interface that is as compact as possible, while maintaining full compatibility with handheld power tools of older series. This should not restrict either the recognition of the correct coding element or any digital communication via the same cable.

[0013] It is a further object of the invention to provide a corresponding hand-held power tool and a corresponding charger which can read as much information as possible from the battery pack while being fully compatible with conventional battery packs.

[0014] These objects are achieved by a battery pack according to claim 1 as well as by a hand-held power tool according to claim 13 and a charger according to claim 15. Advantageous embodiments, variants and further developments of the invention can be found in the subclaims.

[0015] A battery pack according to the invention for a hand-held power tool has at least one interface for establishing an electrical connection of the battery pack to a hand-held power tool and / or a charger, wherein the interface has contact elements for electrically contacting corresponding mating contact elements on the handheld power tool and / or corresponding mating contact elements on the charging device, wherein at least one contact element is a signal contact element which is electrically connected to at least one coding element of the battery pack; battery pack electronics, wherein the battery pack electronics are designed to provide information relating to the battery pack via the at least one signal contact element, wherein the information relating to the battery pack is at least partially stored in the at least one coding element; and wherein in the battery pack electronics, the at least one coding element is connected in an electrical parallel circuit parallel to a dynamic current path.

[0016] For the purposes of this application, a dynamic current path is understood to mean a current path that is temporally variable with respect to certain electrical properties, in particular with respect to a voltage applied to the current path and / or a current flowing through the current path. For the purposes of this application, this characteristic of the dynamic current path is also referred to as time behavior.

[0017] Those skilled in the art will recognize that this dynamic, or this temporal behavior, of a current path connected in parallel to the coding element offers the possibility of encoding at least one additional 1-bit piece of information via the signal contact element in addition to the coding resistor and transmitting it to the handheld power tool and / or the charger, thus eliminating the need for an additional signal contact element to transmit this additional information. This is possible because a control system of the handheld power tool or charger detects the dynamic and interprets it accordingly.

[0018] Advantageously, this timing behavior is electrically tuned to ensure that the dynamics required for digital communication between the battery pack and the handheld power tool or charger are only altered in a negligible way. Specifically, this ensures that the necessary switching thresholds are not significantly affected in time. This ensures that no functional impairment occurs, while at the same time at least one additional piece of information can be transmitted analogically via the coding interface.

[0019] In one embodiment, the battery pack electronics are configured to transmit a supply voltage to the at least one coding element via a series resistor in a handheld power tool or in a charger, wherein the dynamic current path is configured to influence a temporal profile of a measurement voltage across the coding element. In this embodiment, the presence of the described temporal behavior is measured, for example, via a microcontroller on the handheld power tool or charger side by measuring a voltage profile at the coding element during and after the circuit is charged. Any 1-bit information can be encoded via this. For increased information depth, the characteristics of the described temporal behavior can be evaluated, for example.

[0020] Advantageously, the dynamic current path is configured to influence the temporal profile of the measurement voltage across the at least one coding element only within a defined period of time after the supply voltage from the corresponding handheld power tool and / or the corresponding charging device has been applied, wherein the defined period of time is preferably between 0 ms and 10 ms, particularly preferably between 0 ms and 1 ms. In this way, in the specific case, it can be achieved that the temporal behavior is electrically advantageously coordinated so that it has already reached a final value during the static detection of the coding element, for example in such a way that a final value of a voltage difference at the signal contact element generated by the dynamic current path is approximately zero volts.In other words, after the timing has been completed, the voltage at the coding element corresponds to the voltage that would be present even without a dynamic current path connected in parallel to the coding element.

[0021] Preferably, in the battery pack electronics, the signal contact element and the dynamic current path are connected in an electrical parallel circuit between a common ground connection and the signal contact element.

[0022] In a preferred embodiment, the temporal dynamics are achieved in that the dynamic current path comprises at least a first capacitor and a first resistor in series connection. The first capacitor and the first resistor can be arranged in an RC series circuit or in a CR series circuit in a manner known per se to those skilled in the art. The dynamics of the dynamic current path are generated in that the first capacitor charges within a defined time when a DC supply voltage is applied, for example via a pull-up resistor arranged in the interface of the hand-held power tool or the charging device. During charging, the voltage applied to the first resistor is reduced in a manner known per se until the current is zero when the first capacitor is fully charged. The voltage applied across the first resistor is then also zero.

[0023] In a specific embodiment, a capacitance Cx of the at least one first capacitor and a resistance value Rx of the at least one first resistor are selected such that a time constant τ = Rx*Cx of the first capacitor has a value of τ <10ms, preferably τ <1ms.

[0024] In one embodiment of the invention, the dynamic current path comprises two or more first capacitors connected in a parallel and / or series circuit and / or two or more first resistors connected in a parallel and / or series circuit.

[0025] In a further embodiment, the dynamic current path for a battery pack or battery pack type has a defined capacitance value Cx and / or a defined resistance value Rx, which, when a supply voltage (Vcc) from a handheld power tool or charger is applied to the signal contact element, generates a defined time behavior in the measuring voltage across the coding element, wherein this time behavior is distinguishable from the time behavior of other battery packs or battery pack types which, for example, have no or a different type of dynamic current path.

[0026] In this way, theoretically any number of different capacitance values ​​Cx and / or resistance values ​​Rx can be distinguished over time, for example to achieve 8-bit coding.

[0027] In a further embodiment, the battery pack electronics comprises two or more dynamic current paths, wherein each of the two or more dynamic current paths is connected in an electrical parallel circuit in parallel to the at least one coding element, and wherein each of the two or more dynamic current paths has at least one first resistor with resistance value Rx,i and at least one first capacitor with capacitance Cx,i in series connection, wherein each combination of the two or more dynamic current paths within distinguishable battery packs generates a distinguishable time behavior at the interface to the hand tool and / or the charger. As in the embodiment discussed above, any number of bits can be coded in this way.

[0028] According to the invention, it is provided that the battery pack electronics comprises two or more dynamic current paths, wherein each of the two or more dynamic current paths is connected in an electrical parallel circuit parallel to the at least one coding element, and wherein each of the two or more dynamic current paths is constructed analogously to the first dynamic current path with regard to its electrical components and its interconnection.

[0029] In one embodiment of the invention, a protective capacitor or a protective diode is connected in parallel with the at least one coding element in an electrical parallel circuit. This makes it possible to protect the circuit against electrostatic discharge.

[0030] Preferably, the at least one coding element is a coding resistor, particularly preferably an ohmic resistor. In this embodiment, the ohmic resistance value of the ohmic resistor can be used as the coding value of the at least one first coding element.

[0031] According to a further aspect, the present invention comprises a handheld power tool, comprising a battery pack as described above, an interface for electrically coupling the battery pack to the handheld power tool, comprising at least one signal counter-contact element corresponding to the signal contact element of the battery pack; and a control unit, wherein the control unit is designed to receive information relating to the battery pack via the at least one signal counter-contact element; wherein the control unit is designed to detect and evaluate a temporal profile of a measurement voltage applied to the at least one signal counter-contact element.

[0032] The present invention also includes a charger for charging a battery pack as described above, the charger comprising an interface for electrically coupling the charger to the battery pack, comprising at least one charging counter-contact element corresponding to the signal contact element of the battery pack; and a control unit, wherein the control unit is designed to receive information relating to the battery pack via the at least one charging counter-contact element; wherein the control unit is designed to detect and evaluate a temporal profile of a measurement voltage applied to the at least one charging counter-contact element.

[0033] The hand-held power tool according to the invention and the charger according to the invention are capable of reading out at least one additional piece of information compared to the prior art with a simple coding element, and with a corresponding design of the battery pack according to the above descriptions for generating several distinguishable time profiles, even correspondingly more information.

[0034] It can be provided that on the side of the hand-held power tool or the charging device, a pull-up resistor is electrically connected to the at least one signal counter-contact element or the at least one charging counter-contact element.

[0035] Further features, possible applications, and advantages of the invention will become apparent from the following description of the exemplary embodiments of the invention, which are illustrated in the figures. It should be noted that the features illustrated are merely descriptive and can also be used in combination with features of other developments described above. They are not intended to limit the invention in any way. Drawings

[0036] The invention will be described in more detail below with reference to the accompanying figures, in which the same reference numerals are used for the same features. The drawings are schematic and show: Fig. 1 shows an exemplary view of a hand-held power tool with a battery pack according to the invention; Fig. 2 shows a perspective exploded view of an embodiment of a battery pack according to the invention; Fig. 3 shows a schematic representation of an electrical contact between a battery pack-side signal contact element and a machine-side counter-signal contact element according to the prior art; Fig. 4 shows a schematic representation of an electrical contact between a battery pack-side signal contact element and a machine-side counter-signal contact element according to an embodiment of the present invention, at different times; Fig. 5 shows a schematic representation of an electrical contact between a battery pack-side signal contact element and a machine-side counter-signal contact element according to an embodiment of the present invention, at different times; and Fig.6 shows a representation of a measured voltage curve at a signal contact element according to an embodiment of the present invention.

[0037] The Figure 1shows an electrical device designed as a handheld power tool 300, which is embodied, for example, as a cordless drill / driver. Accordingly, in the illustrated embodiment, the handheld power tool 300 is mechanically and electrically connected to a battery pack 100 for mains-independent power supply. However, it should be noted that the present invention is not limited to cordless drill / drivers, but rather can be used with various handheld power tools 300. The handheld power tool 300 has a gear 330 arranged in a housing 305 for transmitting a torque generated by a drive motor 335 to a drive shaft rotating about an axis x, to which drive shaft a tool holder 320 for a tool (not shown) is attached, and a handle 315.Arranged within the housing 305 is an electronics unit 370 which is in electronic and / or mechanical contact with the drive motor 335 and / or the gear 330. The handle 315 serves as a support surface for a hand of an operator of the handheld power tool 300 and typically has a longitudinal axis y, a front side 317 pointing along an axis x in the direction of the tool holder 320, a rear side 316, and two side surfaces 318.

[0038] In the area of ​​the handle 315, a first operating element 310 for supplying power to the drive motor 335 is arranged. The first operating element 310 protrudes from the housing 305 and is manually accessible to the user. This allows, in a manner known per se, a pressure movement of the first operating element 310 to enable control and / or regulation of the drive motor, preferably depending on the adjustment path of the first operating element 310, and also to switch the voltage supply for the drive motor 335 on and / or off. Furthermore, the handheld power tool 300 has a second operating element 312 in the form of a slide switch for setting the direction of rotation of the drive motor 335 of the handheld power tool 300.The second operating element 312 is arranged displaceably perpendicular to the rotational axis x of the drive shaft, in particular of the tool holder 320 of the handheld power tool 300, so that the second operating element 312 can be moved back and forth between a first position, a second position, and a third position when actuated. The first and second positions each determine a direction of rotation of the drive motor. Thus, the user of the handheld power tool 300 can already determine the operating mode in which the handheld power tool 300 is operating based on the positions of the second operating element 312. In addition, the second switching element has a third position, for example a middle position, between the first position and the second position, wherein an electrical, electromechanical and / or mechanical interruption of the motor current occurs in the third position.For example, the operation of the first switching element 310 can be mechanically locked, with the second operating element 312 having a locking effect on the first switching element 310 when moved into a third position. The second operating element 312 can be designed as a slide switch, as shown, or alternatively as a toggle switch.

[0039] The first operating element 310 and the second operating element 312 are arranged along the rotation axis x such that it is possible to operate both the first and the second operating elements 310, 312 with the index finger or middle finger. The distance between the first operating element 310 and the second operating element 312 is selected such that one-handed operation of the handheld power tool 300 is possible. Both operating elements 310, 312 are further arranged in a region below the rotation axis x and protrude from the housing 305.

[0040] In the in the Figure 1In the position shown, the battery pack 100 is attached to the handle 315 of the handheld power tool 300 and locked by locking means. The arrangement of the battery pack 100 below the handle 315 does not interfere with the operation of the handheld power tool 300. The locking means, not shown in detail, include, among other things, a locking element and an actuating element 220. By actuating the actuating element 220, the battery pack 100 can be released from the handle 315 of the handheld power tool 300. Furthermore, the handheld power tool 300 has an interface 380.

[0041] The Figure 1The battery pack 100 shown is designed as a sliding battery pack and has an interface 180 corresponding to the interface 380 of the handheld power tool 300. As an alternative to the sliding battery pack, a design as a rotating or pivoting battery pack is also possible, wherein the battery pack 100 can be releasably locked to the housing 305 of the handheld power tool 300 on the side opposite the pivot axis by latching, screwing, clamping, or bracing. In this way, a possible falling of the battery pack from the housing 305 can be effectively counteracted.

[0042] For detachably attaching the battery pack 100 to a handheld power tool 300 or to a charger, the battery pack 100 has an interface 180 for detachably mechanically and electrically connecting it to a corresponding interface 380 of the handheld power tool 300 or a corresponding interface of the charger. When attaching the battery pack 100, receiving means, e.g., guide grooves and guide ribs, of the handheld power tool 300 or the charger are brought into engagement with the corresponding guide elements of the battery pack 100 for receiving them. The battery pack 100 is inserted along the receiving means, and the interface 180 of the battery pack 100 is pushed into the corresponding interface 380 of the handheld power tool 300 or the corresponding interface of the charger. The battery pack 100 can be assigned to the hand tool 300 and / or the charger via the mechanical design of the interfaces 180, 380.

[0043] For the sake of simplicity, the following explanations of the Figures 2 to 5 A hand tool 300 is mentioned as the device connected to the battery pack, and it is not always mentioned that the device connected to the battery pack 100 can also be a charger 700. The explanations regarding the Figures 3 to 5 However, the same applies to an arrangement of the battery pack 100 on a charger 700.

[0044] To lock the battery pack 100 to the handle 315 of the handheld power tool 300, the battery pack 100 is pushed along the handle 315, specifically along a lower outer surface of the handle 315, which is oriented substantially perpendicular to the longitudinal direction y of the handle 315. In the position shown in Figure 1, the battery pack 100 is locked to the handle 315 by locking means. The locking means include, among other things, a Figure 2illustrated locking element 210 and an actuating means. By actuating the actuating means, the battery pack 100 can be released from the handle 315 of the handheld power tool 300. After unlocking the battery pack 100, it can be separated from the handle 315. When attaching the battery pack 100 to a handheld power tool 300, the locking element 210 is brought into engagement with a corresponding receptacle (not shown in detail) in the handle 315 of the handheld power tool 300.

[0045] As shown in the exploded view of the Figure 2As can be seen, the interface 180 also includes contact elements 140 for electrically contacting the battery pack 100 with the handheld power tool 300 or the charger. The contact elements 140 include both voltage contact elements, which serve as charging and / or discharging contact elements, and signal contact elements, which enable signal transmission from the battery pack 100 to the handheld power tool 300 and / or from the handheld power tool 300 to the battery pack 100. "Signal transmission" is to be understood here as the transmission of information, which in the simplest case is 1-bit information such as "0" or "1", but can also be, for example, a voltage or resistance value.

[0046] As described above, certain signal contact elements on the battery pack side are connected to coding elements, for example, coding resistors, which encode information for the handheld power tool 300 or the charger, such as the maximum charging and discharging current, the current operating temperature, and the internal resistance of the battery pack. A pull-up resistor is typically arranged in the corresponding mating contact elements of the handheld power tool and / or the charger, via which the coding resistor on the battery pack side is supplied with voltage.

[0047] A simplified circuit diagram of such a known arrangement is shown in Figure 3 Here as well as in the Figure 4 and 5 A dashed line represents the interface between the battery pack 100 or battery pack electronics 800 and the hand tool 300 or charger. Figures 3 to 5The connection between the electronics of the battery pack and the electronics of the handheld power tool 300 is marked as a continuous line; the contact elements of the battery pack and machine-side interfaces arranged between the devices are not shown. Also not shown are further details of a battery pack electronics system designed to provide a handheld power tool 300 with information regarding the battery pack 100 via the at least one signal contact element 143. This information regarding the battery pack 100 is at least partially stored in the at least one coding element 141, which will be described in more detail below.

[0048] In the Figure 3In the example shown, the coding element 141 is a resistor with the resistance value Rc. On the side of the handheld power tool 300, a pull-up resistor 341 is shown, via which the coding element 141 is supplied with current. In the embodiment shown, a supply voltage Vcc is applied across the pull-up resistor 341 and the coding element 141. After the supply voltage Vcc is applied, a measuring circuit in the handheld power tool or in the charger determines the resistance connected to the signal contact element, which is interpreted as battery pack-specific information by a corresponding control system of the handheld power tool or charger.

[0049] As described at the beginning, this type of information transfer is limited, in the embodiment shown, to a resistance value.

[0050] In order to overcome this disadvantage and at the same time ensure full compatibility and functionality with state-of-the-art devices, the invention, on the one hand, adheres to applying a measuring voltage to the at least one coding element 141 via the battery pack electronics 800. As shown in Figure 4b As shown, according to the invention, the coding element 141 in the battery pack electronics 800 is furthermore connected in an electrical parallel circuit parallel to a dynamic current path, which can now be seen from the Figure 4 shown embodiment of the invention. In the Figure 4 and 5 have features that are already present in Figure 3 described, the same reference numerals as in Figure 3 .

[0051] In the embodiment of the Figure 4The dynamic current path comprises at least a first resistor 241 with resistance value Rx and a first capacitor 243 with capacitance Cx connected in series. Depending on the embodiment of the invention, the first resistor 241 is arranged upstream of the first capacitor 243 (RC series connection) or downstream of the first capacitor (CR series connection), as seen from the interface, which makes no difference with regard to the technical effect desired here.

[0052] In the battery pack electronics 800, the signal contact element 143 and the dynamic current path are connected in an electrical parallel circuit between a common ground connection and the signal contact element 143, which is indicated by the corresponding ground symbol in the figure.

[0053] If a voltage Vcc is now applied to the Figure 4b shown circuit is applied, then with the first capacitor 243 initially completely discharged, the electrically Figure 4a The situation shown arises, in which the voltage across the dynamic current path and the static path, which contains the time-invariant coding element 141, is divided according to the voltage divider consisting of the pull-up resistor 341 and the parallel circuit of Rc and Rx. This is particularly advantageous because it ensures that a switching threshold, which may be necessary for digital communication between the battery pack 100 and the handheld power tool 300, is exceeded without a significant additional time delay.

[0054] The person skilled in the art will recognize that when the measuring voltage Vc is applied, the capacitor 234 charges to its final value with the time constant τ = Rx*Cx depending on its capacitance Cx and the resistance Rx of the coding element 141. Once this final value is reached, no more current flows through the dynamic current path, and the steady-state voltage value corresponds to the voltage divider consisting of the pull-up resistor 341 and the coding element 141, which in Figure 4c is shown schematically. Electrically speaking, the stationary system appears exactly as if the dynamic current path were not present.

[0055] The time constant τ = Rx*Cx is designed in embodiments of the invention such that at the time of the stationary measurement of the coding element 141 the first capacitor 243 is already sufficiently charged and thus the deviation from the known from the prior art, in Figure 3shown stationary system is negligible. Preferably, the capacitance Cx of the at least one first capacitor 243 and the resistance value Rx of the at least one first resistor 241 are selected such that the time constant τ = Rx*Cx of the first dynamic current path has a value of τ <10 ms, preferably τ <1 ms.

[0056] In this embodiment, the dynamic current path is configured to influence the temporal progression of the measurement voltage Vc only within a defined period of time after connecting the battery pack 100 to the corresponding handheld power tool 100 or the corresponding charger 700. This influence on the temporal progression of the measurement voltage Vc can be detected and evaluated by a correspondingly configured control unit of a handheld power tool 300 or a charger.

[0057] To illustrate this fact, Figure 6by way of example, a time characteristic of a voltage Vc applied to the coding element 141 after application of the supply voltage Vcc as in connection with Figure 4 explained. Time is plotted on the horizontal x-axis, and a normalized voltage at the coding element 141 is plotted on the y-axis perpendicular to it.

[0058] The time course, which is marked with a dotted curve 1001, is based on an example configuration of the Figure 4b The circuit shown is based on the pull-up resistor 341, coding element 141, and first resistor 241 and first capacitor 243 in an RC circuit. The continuous, not further labeled curve 1002 corresponds to the circuit implemented according to the prior art without a dynamic current path, with otherwise unchanged components of pull-up resistor 341 and coding element 141.

[0059] A person skilled in the art will recognize the slight difference in the rising edge of the time profiles 1001, 1002 immediately after the supply voltage Vcc is applied, as well as in the steady state, in which the two time profiles 1001, 1002 approach each other again. The measurable voltage profile in a time window ΔT therebetween is characterized by a deviation of the two time profiles 1001, 1002 in a region 1003, which is influenced by the electrical properties of the dynamic current path and allows conclusions to be drawn about the capacitance Cx and / or the resistance value Rx. The presence of the described time behavior can be monitored, for example, via a microcontroller of the handheld power tool 300 or the charging device by measuring the voltage at the coding element 141 during the charging process of the circuit. Any 1-bit information can be encoded in this way.For increased information depth, the characteristics of the described time behavior can also be evaluated.

[0060] To protect the battery pack electronics 800 from electrostatic discharge, a protective capacitor 145 or a protective diode can be connected in an electrical parallel circuit parallel to the at least one coding element 141 in the prior art, which in Figure 5b is shown. Figure 5b also shows the inventive development of this circuit with a dynamic current path, which as in Figure 4b shown comprises the first resistor 241 with resistance value Rx and the first capacitor 243 with capacitance Cx in series connection.

[0061] If a voltage Vcc is applied to the Figure 5b shown circuit is applied, then with the first capacitor 243 and the protective capacitor 145 completely discharged, the electrical situation shown in Figure 5ashown situation occurs, in which the protective capacitor 145 allows a short circuit to ground and begins to charge due to the current flow.

[0062] This charging process results in the current flow at the first capacitor 241 being equal to zero immediately after the supply voltage Vcc is applied, and in the first capacitor 241 only starting to charge as the protective capacitor 145 increases. When the protective capacitor 145 and the first capacitor 241 are fully charged, the electrical state shown in Figure 5c shown system, which is identical to that of the Figure 4c is.

[0063] In a preferred embodiment, the dynamic current path is characterized by a capacitance value Cx and / or resistance value Rx typical for the battery pack, which, when a supply voltage from a handheld power tool or a charger is applied to the signal contact element, generates a time behavior in the measuring voltage across the coding element that is typical for this battery pack, and this time behavior is distinguishable from the time behavior of other battery packs or battery pack types that are characterized, for example, by dynamic current paths with different capacitance values ​​Cx and / or resistance values ​​Rx or do not contain any dynamic current paths.

[0064] In a further embodiment, the battery pack electronics 800 comprises two or more dynamic current paths, wherein each of the plurality of dynamic current paths is connected in an electrical parallel circuit in parallel with the at least one coding element 141, and wherein each of the plurality of dynamic current paths has at least one first resistor 241 with resistance value Rx,i and at least one capacitor 243 with capacitance Cx,i in series connection. As in the embodiment discussed above, any number of bits can be encoded in this way.

[0065] According to the invention, it is provided that the battery pack electronics 800 comprises two or more dynamic current paths, wherein each of the plurality of dynamic current paths is connected in an electrical parallel circuit parallel to the at least one coding element 141, and wherein each of the plurality of dynamic current paths is constructed analogously to the first dynamic current path with regard to its electrical components and its interconnection.

[0066] Although the invention has been explained in more detail by the preferred embodiments, other combinations of the features mentioned can also be provided by the person skilled in the art without departing from the scope of the invention.

Claims

1. Battery pack (100) for a hand-held power tool (300), having at least one interface (180) for establishing an electrical connection of the battery pack (100) to a hand-held power tool (300) and / or a charger, wherein the interface (180) has contact elements (140) for electrically contacting corresponding mating contact elements (340) on the hand-held power tool (300) and / or corresponding mating contact elements on the charger, wherein at least one contact element (140) is a signal contact element (143) that is electrically connected to at least one coding element (141) of the battery pack (100); battery-pack electronics (800) that are designed to provide information relating to the battery pack (100) via the at least one signal contact element (143), wherein the information relating to the battery pack (100) is stored, at least in part, in the at least one coding element (141); characterized in that the battery-pack electronics (800) comprise two or more dynamic current paths, wherein each of the two or more dynamic current paths is interconnected in an electrical parallel circuit in parallel with the at least one coding element (141), and wherein each of the two or more dynamic current paths is constructed, in respect of its electrical components and its interconnection, in a manner similar to the first dynamic current path.

2. Battery pack (100) according to Claim 1, characterized in that the battery-pack electronics (800) are configured to forward a supply voltage (Vcc) to the at least one coding element (141) via a series resistor in a hand-held power tool or in a charger, and in that the dynamic current path is configured to influence a time characteristic of a measurement voltage (Vc) across the at least one coding element (141).

3. Battery pack (100) according to Claim 2, characterized in that the dynamic current path is configured to influence the time characteristic of the measurement voltage (Vc) across the at least one coding element (141) only within a defined period of time after the supply voltage (Vcc) from the corresponding hand-held power tool (100) or the corresponding charger (700) is applied, wherein the defined period of time is preferably between 0 ms and 10 ms, particularly preferably between 0 ms and 1 ms.

4. Battery pack (100) according to one of the preceding claims, characterized in that, in the battery-pack electronics (800), the signal contact element (143) and the dynamic current path are connected in an electrical parallel circuit between a common ground terminal and the signal contact element (143).

5. Battery pack (100) according to one of the preceding claims, characterized in that the dynamic current path comprises at least one first capacitor (243) and one first resistor (241) connected in series.

6. Battery pack (100) according to Claim 5, characterized in that a capacitance (Cx) of the at least one first capacitor (243) and a resistance value (Rx) of the at least one first resistor (241) are selected in such a manner that a time constant T = Rx*Cx of the first capacitor (241) has a value of T <10 ms, preferably T<1 ms.

7. Battery pack (100) according to either of Claims 5 and 6, characterized in that the dynamic current path has a defined capacitance value Cx and / or a defined resistance value Rx that, when a supply voltage (Vcc) from a hand-held power tool (300) or charger (700) is applied to the signal contact element (143), generate / generates a defined time response in the measurement voltage (Vc) across the coding element (141), wherein this time response is distinguishable from the time response of other battery packs or battery pack types.

8. Battery pack (100) according to one of Claims 5 to 7, characterized in that the battery-pack electronics (800) comprise two or more dynamic current paths, wherein each of the two or more dynamic current paths is interconnected in an electrical parallel circuit in parallel with the at least one coding element (141), and wherein each of the two or more dynamic current paths has at least one first resistor (241) of resistance value Rx,i and at least one first capacitor (243) of capacitance Cx,i connected in series, wherein any combination of the two or more dynamic current paths within battery packs (100, 100') to be distinguished generates a distinguishable time response at the interface with the hand-held power tool (300) and / or the charger.

9. Battery pack (100) according to one of the preceding claims, characterized in that there is a protective capacitor (145) or a protective diode connected in an electrical parallel circuit in parallel with the at least one coding element (141).

10. Battery pack (100) according to one of the preceding claims, characterized in that the at least one coding element (141) is a coding resistor.

11. Battery pack (100) according to one of the preceding claims, characterized in that the at least one first coding element (141) is an ohmic resistor, and a coding value of the at least one first coding element (141) is an ohmic resistance value of the ohmic resistor.

12. Hand-held power tool (300), comprising a battery pack (100) according to one of Claims 1 to 11 ; an interface for electrically coupling the battery pack (100) to the hand-held power tool (300), comprising at least one signal mating-contact element corresponding to the signal contact element (143) of the battery pack (100); and a control unit, wherein the control unit is designed to receive information relating to the battery pack (100) via the at least one signal mating-contact element and to sense and evaluate a time characteristic of a measurement voltage (Vc) applied to the at least one signal mating-contact element.

13. Hand-held power tool (300) according to Claim 12, characterized in that there is a pull-up resistor (341) electrically connected to the at least one signal mating-contact element.

14. Charger for charging a battery pack according to one of Claims 1 to 11, comprising an interface for electrically coupling the charger to the battery pack (100), comprising at least one charging mating-contact element corresponding to the signal contact element (143) of the battery pack (100); and a control unit, wherein the control unit is designed to receive information relating to the battery pack (100) via the at least one charging mating-contact element and to sense and evaluate a time characteristic of a measurement voltage (Vc) applied to the at least one charging mating-contact element.