Method of detecting an electrical fault condition of a replaceable battery pack and / or an electrical device capable of being connected thereto and system performing the method

Abstract

The invention relates to a method for detecting an electrical fault condition of a replaceable battery pack (10) and / or of an electrical device (16) which can be connected to the replaceable battery pack, in particular a charging device (18), a diagnostic device (20) or a consumer (22), by means of a first monitoring unit (56) integrated in the replaceable battery pack. It is proposed that a charging or discharging current (I) is measured by means of a first current measuring device (84) integrated in the electrical device and is transmitted directly or as a converted voltage value (U Charge ) to the first monitoring unit of the replaceable battery pack, and that the first monitoring unit determines whether the replaceable battery pack is working in an allowed operating range on the basis of the charging or discharging current and / or voltage value calculated therefrom. The invention also relates to a system comprising a replaceable battery pack and an electrical device for carrying out the method.

Description

Technical Field

[0001] This invention relates to a method for detecting electrical fault conditions in a replaceable battery pack and / or electrical equipment (especially charging equipment, diagnostic equipment, or power consumers) that can be connected to the replaceable battery pack by means of a first monitoring unit integrated in the replaceable battery pack. The invention also relates to a system for performing this method. Background Technology

[0002] Numerous power consumers operate using a battery pack (hereinafter referred to as a replaceable battery pack) that can be replaced by the operator without tools. This battery pack is discharged by the power consumers and can be recharged using a charging device. Typically, such a replaceable battery pack consists of multiple energy storage battery cells interconnected in series and / or parallel to achieve the desired replaceable battery pack voltage or capacity. High power density and energy density can be particularly advantageously achieved if the energy storage battery cells are constructed, for example, as lithium-ion battery cells (Li-ion). On the other hand, to avoid electrical failure conditions, such battery cells must also comply with stringent specifications regarding maximum charging and discharging current, voltage, and temperature.

[0003] In modern replaceable battery packs, the cell voltages of energy storage battery cells connected in parallel, known as battery cell clusters, are analyzed and processed, for example, by a monitoring unit integrated within the replaceable battery pack. Therefore, the term "cell voltage" should be understood not only as the voltage of a single energy storage battery cell but also as the voltage of a battery cell cluster consisting of energy storage battery cells connected in parallel. This so-called Single-Cell Monitoring (SCM) is known, for example, from WO 20043386 A1, where redundant monitoring also eliminates dangerous operation of the replaceable battery pack in the event of a fault.

[0004] For charging devices or power consumers to know the maximum allowable charging or discharging current for a replaceable battery pack, this is typically communicated via electrical coding (e.g., via a coded resistor integrated into the replaceable battery pack, which is measured by the device and compared to a stored table), mechanical coding, or a communication interface. Similarly, as known from DE 10 2016 209 822 A1, the device informs the replaceable battery pack that its continued use is no longer permitted. This interface can also transmit battery cell voltages to the device.

[0005] In battery packs where the expected charging current is much smaller than the discharging current, measurement systems typically reach their limits. A typical measuring device, for example, is a so-called shunt in the current path—a resistor with a relatively low defined resistance value. On the one hand, the resistance must be so low that it does not generate any dangerous heat during nominal operation; on the other hand, the voltage drop across the shunt due to the charging or discharging current must be high enough for accurate measurement. Therefore, such a shunt must have very low resistance for high currents to avoid generating any heat, but especially at small charging currents, it produces a very small voltage drop that can lead to relatively inaccurate measurements. While switching between different shunts is conceivable, this relies on the switching elements in replaceable battery packs, which again introduce undesirable losses in this regard. Summary of the Invention

[0006] Based on existing technology, the objective of this invention is to accurately identify potential fault conditions in replaceable battery packs and / or electrical equipment that can be connected thereto, not only for high but also for low charging or discharging currents, and to control the charging or discharging process accordingly, so as to ensure safe operation.

[0007] Advantages of the present invention

[0008] According to the present invention, a first current measuring device integrated into the electrical equipment measures the charging or discharging current and transmits it directly or as a converted voltage value to a first monitoring unit of the replaceable battery pack. The first monitoring unit then determines whether the replaceable battery pack is operating within its permissible operating range based on the calculated charging or discharging current and / or voltage value. A particular advantage of transferring the current measuring device to the charging device, especially when the electrical equipment is configured as a charging device, is that the current measuring device need not be able to handle very high discharging currents, but only relatively low charging currents. Thus, a current measuring device in the replaceable battery pack that must be able to handle discharging currents up to 250A would be significantly more expensive than a current measuring device in the charging device that handles only about 16A or less of charging current. However, even in the case of power consumption devices or diagnostic equipment, the adjusted current measuring device can be better matched to the corresponding discharging current, thereby effectively avoiding the disadvantages described at the beginning of the discussion regarding the current measuring device integrated into the replaceable battery pack.

[0009] In the context of this invention, power supplies should be understood as, for example, power tools that operate on replaceable battery packs and are used to process workpieces by means of an electric insert tool. Here, power tools can be configured not only as handheld power tools but also as stationary power tools. Typical power tools in this case include handheld or vertical drills, screwdrivers, impact drills, hammer drills, planers, angle grinders, orbital grinders, polishers, circular saws, table saws, oscillating saws, and wire saws. However, gardening equipment (e.g., lawnmowers, lawn trimmers, pruning saws, etc.) and household appliances (e.g., vacuum cleaners, blenders, etc.) that operate on replaceable battery packs can also be used as power supplies. Similarly, this invention can be applied to power supplies supplied with multiple replaceable battery packs simultaneously.

[0010] The voltage of a replaceable battery pack is typically several times the voltage of a single energy storage battery cell and is generated by the interconnection (parallel or series) of these individual energy storage battery cells. The energy storage battery cell is typically constructed as a primary cell, with one cell electrode located at one end and the other at the opposite end. Specifically, the energy storage battery cell has a positive cell electrode at one end and a negative cell electrode at the opposite end. The energy storage battery cell is preferably constructed as a lithium-based energy storage battery cell, such as lithium-ion, lithium polymer, lithium metal, etc. However, the invention can also be applied to replaceable battery packs with Ni-Cd, Ni-MH, or other suitable battery cell types. In common lithium-ion energy storage battery cells with a cell voltage of 3.6V, voltage levels such as 3.6V, 7.2V, 10.8V, 14.4V, 18V, and 36V are derived. Preferably, the energy storage battery cell is constructed as a circular battery cell that is at least substantially cylindrical, wherein the battery cell electrodes are arranged at the cylindrical ends. However, the present invention is not dependent on the type and configuration of the energy storage battery cell used, but can be applied to any replaceable battery pack and energy storage battery cell, such as pouch cell cells in addition to circular battery cells.

[0011] It should also be noted that the configuration of the electromechanical interface of the replaceable battery pack and the configuration of the electromechanical interface of the electrical equipment that can be connected to the replaceable battery pack, as well as the releasability of force-locking and / or form-locking engagements, are important considerations. The specific housing to which the connection is located should not be the subject of this invention. Those skilled in the art will select a suitable implementation for the interface based on the power or voltage rating of the electrical equipment and / or replaceable battery pack. Therefore, the embodiments shown in the accompanying drawings are merely illustrative. Thus, interfaces with more electrical contacts (Kontakt) than shown may also be used.

[0012] In another configuration of the method according to the invention, the charging or discharging current calculated by the first monitoring unit is transmitted to another monitoring unit of the electrical device, and the charging or discharging current is measured by means of a second current measuring device of the electrical device and compared by the other monitoring unit of the electrical device with the charging or discharging current calculated by the first monitoring unit. In this way, a simple and effective reliability check can be performed in the electrical device. The second current measuring device of the electrical device can advantageously be configured similarly to the first current measuring device.

[0013] For a first current measuring device for electrical equipment, at least one unacceptable voltage range and at least one permissible voltage range are defined for the measured charging or discharging current, wherein a linear, nonlinear, or discontinuous current-voltage transfer function is provided within the at least one permissible voltage range. Advantageously, the current-voltage transfer function of the first monitoring unit of the replaceable battery pack is known, thereby allowing the first monitoring unit to perform corresponding reliability checks for the permissible operating range very simply and quickly. Furthermore, the first monitoring unit in the replaceable battery pack can immediately assess whether electrical equipment without a corresponding current measuring device is being used.

[0014] In another configuration, the first monitoring unit can be matched with the amplification circuitry of the replaceable battery pack for amplifying the measured charging or discharging current or the voltage value derived therefrom, so that a voltage value within the measurement range is obtained even if the voltage value is outside the measurement range. Since the first monitoring unit itself possesses knowledge about this switching, it can advantageously interpret and assess a currently smaller measured voltage as a actually higher voltage.

[0015] If the calculated and measured charging or discharging currents differ by a defined difference, for example, greater than 0.5A, another monitoring unit of the charging device 18 stops or reduces the charging or discharging process, and / or signals the fault status of the replaceable battery pack.

[0016] The present invention also relates to a system comprising a replaceable battery pack having a first monitoring unit and a first electromechanical interface having a plurality of electrical contacts, and an electrical device, particularly a charging device, diagnostic device, or power consumer, having another monitoring unit, a first current measuring device, and another electromechanical interface having a plurality of electrical contacts, wherein each of the first electrical contacts of these interfaces is configured as an energy supply contact capable of being loaded with a first reference potential, preferably a supply potential; each of the second electrical contacts of these interfaces is configured as an energy supply contact capable of being loaded with a second reference potential, preferably a ground potential; and each of the third electrical contacts of these interfaces is configured as a signal or data contact for transmitting a charging or discharging current or a voltage value derived therefrom, measured by the first current measuring device of the electrical device, to the first monitoring unit of the replaceable battery pack, wherein the electrical contacts of the first and second interfaces can be connected to perform the method according to any one of the above-described technical solutions.

[0017] The replaceable battery pack includes a measuring amplifier connected on its input side to a third electrical contact of the first interface, configured as a signal or data contact, and on its output side to a first monitoring unit. Furthermore, the replaceable battery pack may include a resistive element connected on one side to the third electrical contact configured as a signal or data contact, and on the other side to a second electrical contact of the first interface configured as an energy supply contact. The resistive element is particularly advantageously configured as an coded resistor for identifying the replaceable battery pack within the power consumer. Therefore, it is unnecessary to install other resistive elements within the replaceable battery pack. Moreover, the value of the coded resistor is known to the other monitoring unit of the power consumer.

[0018] In an alternative configuration, the third electrical contact of the first interface, which is constructed as a signal or data contact, can also be connected to the first monitoring unit via a simple filtering circuit (e.g., a diode) or directly.

[0019] The measurement amplifier of the replaceable battery pack can be controlled by the first monitoring unit of the replaceable battery pack. In this way, the measurement range of the first monitoring unit can be matched as necessary to interpret and evaluate smaller measured voltage values ​​as actually higher voltage values.

[0020] According to another configuration of the system of the present invention, the first current measuring device of the electrical equipment has a first current measuring amplifier, which is connected to a first current sensor on the input side and connected to a third electrical contact of another interface configured as a signal or data contact on the output side via a pull-up resistor. The first current sensor is connected to a second electrical contact of another interface configured as an energy supply contact.

[0021] Furthermore, it is particularly advantageous that the first monitoring unit of the replaceable battery pack evaluates the charging or discharging current as permissible or impermissible based on its known resistance values ​​of resistive elements and pull-up resistors, as well as the current-voltage transfer function of the first current measuring device of the electrical equipment. This yields the advantages already described in conjunction with the method according to the invention.

[0022] As a supplement, the electrical equipment also includes a second current measuring device for measuring the charging or discharging current by means of a second current sensor, which is connected in series with the first current sensor of the first current measuring device. The first and second current sensors can be configured as shunt resistors, Hall effect sensors, magnetic field sensors, electrically isolated current clamps, etc. The second current measuring device of the electrical equipment has a second current measuring amplifier, through which it is connected to another monitoring unit. The first monitoring unit of the replaceable battery pack transmits the charging or discharging current calculated therefrom to another monitoring unit of the electrical equipment via a fourth electrical contact configured as a signal or data contact of an interface, wherein the other monitoring unit compares the calculated and measured charging or discharging currents with each other. Particularly advantageously, this allows for a reliability check of the charging or discharging current, as described in conjunction with the method according to the invention. Attached Figure Description

[0023] The following reference Figure 1 The present invention is illustrated by way of example in Figure 3, wherein the same reference numerals in the figures denote the same components having the same mode of operation.

[0024] The attached diagram shows:

[0025] Figure 1 A system is illustrated schematically, comprising at least one replaceable battery pack and at least one electrical device capable of being connected to the replaceable battery pack for charging or discharging the replaceable battery pack.

[0026] Figure 2 Shown in block diagram Figure 1 The system in question includes replaceable battery packs and electrical equipment configured as charging devices, as well as...

[0027] Figure 3 illustrates a first embodiment of the transfer function of at least one current measuring device integrated in an electrical device. Figure 3a ), Second embodiment ( Figure 3b ), Third embodiment ( Figure 3c ) and the fourth embodiment ( Figure 3d ). Detailed Implementation

[0028] Figure 1A system is shown that includes a replaceable battery pack 10 having a first electromechanical interface 14 and electrical devices 16, particularly a charging device 18, a diagnostic device 20, or a power consumer 22 having another electromechanical interface 24, the first electromechanical interface having a plurality of electrical contacts 12, and the other electromechanical interface having a plurality of electrical contacts 12. Figure 1 The purpose is to illustrate that the system according to the invention is applicable to various electrical devices 16 operating with the aid of replaceable battery packs 10 without limiting the invention. Examples here include a battery-powered vacuum cleaner 26, a battery-powered impact screwdriver 28, and a battery-powered lawnmower 30. However, in the context of the invention, a wide variety of power tools, gardening equipment, and household appliances can be used as power sources 22. The number of replaceable battery packs 10 within the system is also variable. Thus, the system can certainly include multiple replaceable battery packs 10. It should also be noted that... Figure 1 Although the charging device 18 and the diagnostic device 20 are shown as the same electrical device 16, since the charging device 18 can also have a diagnostic function, it is conceivable without limiting the invention that the diagnostic device 20 does not have a charging function, but is only used for pure diagnosis of electrical fault conditions of the replaceable battery pack 10.

[0029] The replaceable battery pack 10 essentially relates to a conventional replaceable battery pack having a housing 32 with a first electromechanical interface 14 on a first sidewall or its upper side 34 for detachable connection to an electromechanical interface 24 of an electrical device 16. When connected to a power consumer 22, the first and second electromechanical interfaces 14, 24 are primarily used for discharging the replaceable battery pack 10; when connected to a charging device 18, they are used for charging; and when connected to a diagnostic device 20, they are used for fault diagnosis of the replaceable battery pack 10. The exact configuration of the first and second electromechanical interfaces 14, 24 depends on various factors, such as the voltage rating of the replaceable battery pack 10 or the electrical device 16 and various manufacturer specifications. Thus, for example, three or more electrical contacts 12 may be provided for energy and / or data transfer between the replaceable battery pack 10 and the electrical device 16. Mechanical coding is also conceivable, so that the replaceable battery pack 10 can only operate on a specific electrical device 16. Since the mechanical configurations of the first electromechanical interface 14 of the replaceable battery pack and the other electromechanical interface 24 of the electrical device 16 are not important to the present invention, they will not be discussed in further detail. Not only those skilled in the art, but also operators of the replaceable battery pack 14 and the electrical device 16 will make appropriate choices in this regard.

[0030] The replaceable battery pack 10 has a mechanical locking device 36 for locking a form-locking and / or force-locking releasable connection between the first electromechanical interface 14 of the replaceable battery pack 10 and the corresponding corresponding interface 24 (not shown in detail) of the power consumer 22. Here, the locking device 36 is configured as a spring-loaded button 38, which is effectively connected to the locking member 40 of the replaceable battery pack 10. Due to the springing of the button 38 and / or the locking member 40, the locking device 36 automatically engages when the replaceable battery pack 10 is pushed into the corresponding interface 24 of the power consumer 22. If the operator presses the button 38 in the pushing direction, the lock is released, and the operator can remove or push the replaceable battery pack 10 out of the power consumer 22 in the opposite direction.

[0031] As mentioned at the beginning, the battery voltage of the replaceable battery pack 10 is typically derived from multiples of the individual voltages of the energy storage battery cells (not shown) based on the interconnection (parallel or series) of the energy storage battery cells. Preferably, the energy storage battery cells are constructed as lithium-based battery cells, such as lithium-ion, lithium polymer, lithium metal, etc. However, the present invention can also be applied to replaceable battery packs having Ni-Cd battery cells, Ni-MH battery cells, or other suitable battery cell types.

[0032] exist Figure 2 The diagram is shown in the middle. Figure 1 The system includes a replaceable battery pack 10 on the left and an electrical device 16 configured as a charging device 18 on the right. The replaceable battery pack 10 and the charging device 18 have corresponding electromechanical interfaces 14 and 24 with multiple electrical contacts 12, wherein each first electrical contact of the electrical contacts 12 of interfaces 14 and 24 serves to supply a first reference potential V1, preferably a potential V. + The power supply contact 42 is loaded, and the respective second electrical contact of the electrical contacts 12 of interfaces 14 and 24 serves as a power supply contact 44 capable of being loaded with a second reference potential V2, preferably a ground potential GND. On one hand, the replaceable battery pack 10 can be charged by the charging device 18 through the first and second power supply contacts 42 and 44. On the other hand, in the case where the electrical device 16 is configured as a power consumer 22, the replaceable battery pack 10 is also discharged through the first and second power supply contacts. The term "capable of being loaded" is intended to indicate, especially in the case of the electrical device 16 configured as a power consumer 22, that the potential V2 is loaded. + GND is not continuously applied to the power supply contacts 42, 44, but only after the electrical interfaces 14, 24 are connected. The corresponding situation applies to a discharged replaceable battery pack 10 after it is connected to the charging device 18.

[0033] The replaceable battery pack 10 has multiple energy storage battery cells 46, which, although in Figure 2 The circuit is shown as a series circuit, but alternative or additional grounds can also operate in a parallel circuit. The series circuit defines the voltage U that drops across the energy supply contacts 42, 44 of the replaceable battery pack. Batt The parallel circuit of individual energy storage battery cells 46 primarily increases the capacity of the replaceable battery pack 10. As already mentioned, individual battery cell clusters consisting of parallel-interconnected energy storage battery cells 46 can also be connected in series to achieve a specific voltage U for the replaceable battery pack while simultaneously increasing capacity. Batt In this embodiment, the battery cell voltage U is 3.6V. Cell In the case of a commonly used lithium-ion energy storage battery cell 46, the replaceable battery pack voltage U drops by 5.3.6V = 18V at the energy supply contacts 42 and 44. Batt =V1-V2. Depending on the number of energy storage battery cells 46 connected in parallel in the battery cell cluster, the capacity of a commonly used replaceable battery pack 10 can be up to 12Ah or more. However, the present invention is not dependent on the type, configuration, voltage, current carrying capacity, etc. of the energy storage battery cells 46 used, but can be applied to any replaceable battery pack 10 and energy storage battery cells 46.

[0034] To monitor individual energy storage battery cells 46 or battery cell clusters connected in series in the replaceable battery pack 10, an SCM preparatory stage 48 (individual battery cell monitoring) is provided. The SCM preparatory stage 48 has a multiplexed measurement device 50 that can be connected in a high-ohm manner to the corresponding tap 54 of the terminal of the energy storage battery cell 46 or battery cell cluster via a filter resistor 52. This is to detect the voltage U of each individual battery cell. Cell The multiplexing measurement device 50, for example, switches sequentially between the various taps 54 via integrated, but not shown in more detail, transistors, such that it is connected to the positive and negative terminals of the energy storage battery cell 46 or the battery cell cluster to be measured, respectively. In the following text, the term "energy storage battery cell" should also include the battery cell cluster, as it only affects the capacity of the replaceable battery pack 10, but not the battery cell voltage U. Cell The detection is synonymous. In particular, the high-ohmic configuration of the filter resistor 52 can prevent dangerous heating of the measurement input of the multiplexed measurement device 50, especially in fault conditions.

[0035] Switching of the multiplexing measurement device 50 is performed via a first monitoring unit 56 integrated in the replaceable battery pack 10. It can also close or open a switching element 58 of the SCM pre-stage 48 connected in parallel with the energy storage battery cells 46, thereby achieving a so-called balancing of the energy storage battery cells 46 to achieve a uniform charge or discharge state of the individual energy storage battery cells 46. It is also conceivable that the SCM pre-stage 48 will measure the battery cell voltage U... Cell The battery cell voltage U is directly delivered to the first monitoring unit 56. Cell The actual measurement is performed directly by the first monitoring unit 56, for example, through a corresponding analog-to-digital converter (ADC).

[0036] The first monitoring unit 56 can be constructed as an integrated circuit in the form of a microprocessor, ASIC, DSP, etc. However, it is also conceivable that the monitoring unit 56 consists of multiple microprocessors or at least partially consists of discrete components with corresponding transistor logic. Furthermore, the first monitoring unit 56 may have a memory for storing operating parameters of the replaceable battery pack 10, such as voltage U. Batt Battery cell voltage U Cell Temperature T, charging or discharging current I, etc.

[0037] In addition to the first monitoring unit 56 in the replaceable battery pack 10, the system's electrical equipment 16 also has another monitoring unit 60, which can be configured corresponding to the first monitoring unit 56. The first and the other monitoring units 56 and 60 can exchange information, preferably digitally, through the configuration of two electromechanical interfaces 14, 24 as another contact 12 of signal or data contact 62.

[0038] Another monitoring unit 60 of the electrical device 16, configured as a charging device 18, controls a power output stage 64 connected to the first and second energy supply contacts 42, 44 of another interface 24. Through this power output stage, the replaceable battery pack 10 inserted into the charging device 18 can be charged with a charging current I and a voltage U corresponding to the replaceable battery pack 10. Batt Charging. For this purpose, the charging device 18 or the power output stage 64 is provided with a power grid connection (not shown). A voltage U is applied to the energy supply contacts 42, 44. Batt The voltage can be measured by the voltage measuring device 66 in the charging device 18 and analyzed by another monitoring unit 60. The voltage measuring device 66 can also be fully or partially integrated into the monitoring unit 60, for example, in the form of an integrated ADC.

[0039] A temperature sensor 68 disposed in the replaceable battery pack 10 can measure the temperature T of the replaceable battery pack 10 or the energy storage battery cell 46 and analyze it by another monitoring unit 60 of the charging device 18. This temperature sensor is preferably configured as an NTC and makes close thermal contact with at least one of the energy storage battery cells 46. For this purpose, the temperature sensor 68 is connected, on the one hand, to a second reference potential V2 applied to the second energy supply contact 44, particularly to the ground potential GND, via a switching element 70 (e.g., a bipolar transistor or MOSFET) integrated in the replaceable battery pack 10, and on the other hand, to a contact 12 of the first interface 14 of the replaceable battery pack 10, configured as a signal or data contact 72. Correspondingly, a signal or data contact 72 is provided in another interface 24 of the charging device 18, which is connected to another monitoring unit 60. Furthermore, there is a connection between the signal or data contact 72 of the first interface 14 of the replaceable battery pack 10 and the first monitoring unit 56 of the replaceable battery pack 10. Through this connection, the first monitoring unit 56 can determine whether the temperature T measured by the temperature sensor 68 has been queried by another monitoring unit 60 of the charging device 18. If so, the first monitoring unit 56 automatically switches from sleep mode to operating mode. If no such query has been made, the sleep mode of the first monitoring unit 56 allows for a significantly longer sleep and storage time for the replaceable battery pack 10 due to reduced sleep current.

[0040] In order for the charging device 18 to identify the replaceable battery pack 10 and, if necessary, permit charging of the replaceable battery pack, the replaceable battery pack 10 has a first coded resistor 74. This first coded resistor is connected on one side to a second reference potential V2 applied to the second energy supply contact 44, particularly to the ground potential GND, and on the other side to a contact 12 of the first interface 14 of the replaceable battery pack 10, which is configured as a signal or data contact 62. If the resistance value of the first coded resistor 74 matches the value stored in another monitoring unit 56 of the charging device 60, the charging device 18 permits the charging process and, corresponding to the charging parameters stored in the lookup table (particularly the charging current I, charging voltage U...),... BattThe replaceable battery pack 10 is charged using a method that considers factors such as the allowable temperature range. In addition to the first coded resistor 74, the replaceable battery pack 10 also includes a second coded resistor 76, which is connected, corresponding to the first coded resistor 74, to a second reference potential V2 and another contact 12 of the first interface 14 of the replaceable battery pack 10, configured as a signal or data contact 78. Through the second coded resistor 76, the electrical device 16, configured as a power consumer 22, can permit the discharge process of the replaceable battery pack 10. For this purpose, similar to the charging device 18, the power consumer 22 has another monitoring unit 60 that queries the resistance value of the second coded resistor 76 through the contact 12 of another interface 24, configured as a signal or data contact 78, and compares it with a stored value. If these values ​​are inconsistent, the discharge process of the replaceable battery pack 10 is stopped or not permitted, thus preventing the power consumer 22 from operating. If they are consistent, the operator can put the power consumer 22 into operation. Particularly advantageously, this allows for the operation of replaceable battery packs 10 with different power ratings having the same electromechanical interface 14 or 24. It goes without saying that the power output stage 64 included in the charging device 18 is configured as a drive battery unit in the case of the power consumer 22, for example, as an electric motor (possibly with a corresponding power output stage connected upstream) or another power-consuming unit. Such unit configurations will not be discussed further here, as the various types of power consumers 22 are well known to those skilled in the art, and furthermore, they are not of decisive significance to the invention itself.

[0041] The replaceable battery pack 10 has a measurement amplifier 80, which is connected on the input side between another electrical contact 12 of the first interface 14, configured as a signal or data contact 78, and a second coded resistor 76. On the output side, the measurement amplifier 80 is connected to a first monitoring unit 56 of the replaceable battery pack 10. If necessary, the gain of the measurement amplifier 80 can be adjusted by the first monitoring unit 56 via appropriate control lines. Alternatively, it is conceivable that the second coded resistor 76 is connected directly or via a filter circuit 82 (e.g., a protection diode) to the first monitoring unit 56. This option is... Figure 2 It is shown in dashed lines.

[0042] The charging device 18 has a first current measuring device 84 with a first current measuring amplifier 86. This first current measuring amplifier is connected to a first current sensor 88 on its input side and to a signal or data contact 78 of another interface 24 via a pull-up resistor 90 on its output side. The first current sensor is connected to a second power supply contact 44 of the other interface 24. The first current sensor 88 can be configured as, for example, a shunt resistor, a Hall sensor, a magnetic field sensor, an electrically isolated current clamp, etc. The first current measuring amplifier 86 can be configured as a microcontroller, an operational amplifier, a corresponding discrete circuit, etc. Therefore, a potential is generated on the signal or data contact 78, which is generated by the second encoding resistor 76 of the replaceable battery pack 10, the pull-up resistor 90 in the charging device 18, and the charging current I.

[0043] As a supplement to the first current measuring device 84, the charging device 18 also includes a second current measuring device 92 for measuring the charging current I using a second current measuring amplifier 94 and a second current sensor 96, which is connected in series with the first current sensor 88 of the first current measuring device 84. For this purpose, the second current measuring device 92 is connected to another monitoring unit 60 of the charging device 18. Alternatively, the second current sensor 96 can also be connected directly or via a filter circuit, for example in the form of an inserted protection diode, to the other monitoring unit 60, provided that the other monitoring unit has a corresponding ADC. For clarity, this option is not mentioned. Figure 2 As shown in the figure. The second current sensor 96 and the second current measuring amplifier 94 can be constructed in accordance with the first current sensor 88 and the first current measuring amplifier 86.

[0044] For the first monitoring unit 56 of the replaceable battery pack 10, the resistance values ​​of the second encoding resistor 76 and the pull-up resistor 90 are known as fixed values. Similarly, the first monitoring unit knows the transfer function of the first current measuring device 84 of the charging device 18. Based on these parameters, the first monitoring unit 56 can calculate the charging current I and evaluate whether the charging current is suitable for the replaceable battery pack 10. The first monitoring unit 56 will then convert the calculated charging current I or the corresponding converted voltage value U... Charge The signal or data contacts 62 of interfaces 14 and 24 are transmitted to another monitoring unit 60 of the charging device 18, so that the other monitoring unit 60 can compare the charging current I calculated in the replaceable battery pack 10 with the charging current I measured in the charging device 18 in order to assess whether the replaceable battery pack 10 is operating within the allowable operating range.

[0045] If the calculated and measured charging currents I differ from each other by a defined difference I DiffFor example, if the phase difference is greater than 0.5A, the charging process will eventually be stopped or reduced by another monitoring unit 60 of the charging device 18, and / or the fault status of the replaceable battery pack 10 will be notified by a signal.

[0046] According to Figure 3, for the first current measuring device 84 of the charging device 18, at least one unacceptable voltage range 98 and at least one permissible voltage range 100 are defined for the measured charging current I, wherein a linear, nonlinear, or discontinuous current-voltage transfer function 102 is provided in the at least one permissible voltage range 100. Here, the transfer function 102 of the second current measuring amplifier 94 is advantageously selected such that the reliability of the output signal can be verified by means of the output signal delivered by the first current measuring amplifier 86.

[0047] exist Figure 3a The diagram shows a first possible transfer function 102a for the first current measuring device 84. Based on this, two forbidden voltage ranges 98a are defined as U. Charge =0 to 1V and U Charge >3V, therefore the allowable voltage range is 1V<=U for 100A. Charge <= 3V. Within the permissible voltage range of 100A, the voltage U Charge The charging current I represents 10 A / V, which has the following linear transfer function 102a:

[0048] I = 10A * (U Charge -1V) / V

[0049] exist Figure 3b Another transfer function 102b is shown, in which the unacceptable voltage range 98b and the permissible voltage range 100b correspond to... Figure 3a Those. The transfer function 102b now has a negative slope, where:

[0050] I = –10A*(U Charge –3V) / V

[0051] Therefore, the first monitoring unit 56 of the replaceable battery pack 10 can distinguish whether there is an allowed output signal or whether a charging device 18 without corresponding current measuring devices 84, 96 is being used.

[0052] according to Figure 3c The transfer function 102c can also have a non-linear, especially logarithmic, trend. Therefore, the first monitoring unit 56, for example, will transfer data from U... Charge =1V to U Charge =1.1V jump is identified as a 7A change in charging current I, and will be from U Charge =2.9V to U ChargeA jump of 3V is identified as a 0.2A change in charging current. This representation has the advantage that it can measure lower currents in absolute value more accurately than higher currents.

[0053] In another configuration of the invention, according to Figure 3d The transfer function 102d can also have jump points. Here, the first part of the transfer function 102d, along with the associated, disallowed, and permitted voltage ranges 98d and 100d, corresponds to the voltage ranges from... Figure 3b Those, and in 4V<=U Charge Within the second permissible voltage range of 100d <= 12V, the slope of 20A / V is based on the second linear partial transfer function 102d.

[0054] I = 20A * (U Charge -3V) / V

[0055] The defined range is 20 to 180A of charging current, which can be mapped to this range.

[0056] It is also conceivable that the slope of the second part of the transfer function 100d deviates from the slope of the first part of the transfer function 100d. Both slopes can also be positive or negative. A particular advantage is that the replaceable battery pack 10 (for which only the charging current I within the first permissible voltage range 100d is important) does not need to have a measuring amplifier 80 capable of covering the second permissible voltage range 100d. If another monitoring unit 60 of the charging device 18 needs to transmit a voltage value U located outside the first permissible voltage range 100d... Charge If the first monitoring unit 56 of the replaceable battery pack 10 identifies it as disallowed regardless, then the first monitoring unit 56 of the replaceable battery pack 10 does not need to identify, for example, a voltage value U corresponding to 5V with I=40A. Charge Because for this first monitoring unit, the voltage value U Charge >3V is not allowed under any circumstances. Therefore, on the one hand, the system can be configured as simply as possible, but on the other hand, it can still be configured for the future.

[0057] The first monitoring unit 56 of the replaceable battery pack can be matched to amplify the measured charging current I or the voltage value U derived therefrom. Charge The measurement amplifier 80 makes the applied voltage U Charge When the voltage U is outside the measurement range, the voltage U within the measurement range is obtained. Charge Since the first monitoring unit 56 itself possesses knowledge about the switching, it can measure the voltage U, which is currently being measured at a smaller value. Charge The interpretation and assessment are based on a higher voltage than actually is.

[0058] To display the detected fault condition, the charging device 18 and / or the replaceable battery pack 10 have a corresponding display (not shown in detail) in the form of an LED, a display, and / or an audio signal generator. If the device 18 is configured as a diagnostic device 20 or a power consumer 22, the display may also be supplementarily or alternatively configured as a tactile signal generator, for example, in the form of a vibrating motor. In the case of an electrically driven power consumer 22, it is also conceivable that the drive motor for inserting the tool may function as a tactile and / or acoustic signal generator.

[0059] Finally, it should be noted that the embodiments shown are not limited to... Figure 1 Figure 3 is not limited to the number and type of replaceable battery pack 10 and electrical equipment 16 shown therein. The corresponding cases apply to the number of energy storage battery cells 46 and the number of related configurations of multiplexing measurement devices 48. Furthermore, the configurations of interfaces 14 and 24 shown, the number of their contacts 12, and the transfer functions with the illustrated current and voltage values ​​are for illustrative purposes only.

Claims

1. A method for detecting an electrical fault state of a replaceable battery pack (10) and / or an electrical device (16) connectable to the replaceable battery pack (10) by means of a first monitoring unit (56), said electrical device being a charging device (18), a diagnostic device (20), or a power consumer (22), wherein the first monitoring unit (56) is integrated in the replaceable battery pack (10), characterized in that, The charging or discharging current (I) is measured by means of a first current measuring device (84) integrated in the electrical device (16), and the charging or discharging current is directly or as a converted voltage value (U). Charge The first monitoring unit (56) transmits the measured charging or discharging current (I) to the replaceable battery pack (10), wherein the first current measuring device (84) for the electrical equipment (16) defines at least one unacceptable voltage range (98) and at least one permissible voltage range (100, 104) for the measured charging or discharging current (I), wherein a linear, nonlinear or discontinuous current-voltage transfer function (102) is provided in the at least one permissible voltage range (100, 104), and the first monitoring unit (56) calculates the charging or discharging current (I) and / or voltage value (U) based on the known current-voltage transfer function (102). Charge ) Determine whether the replaceable battery pack (10) is operating within the permissible operating range.

2. The method according to claim 1, characterized in that, The charging or discharging current (I) calculated by the first monitoring unit (56) is transmitted to another monitoring unit (60) of the electrical device (16), and the charging or discharging current (I) is measured by the second current measuring device (92) of the electrical device (16), and the charging or discharging current is compared with the charging or discharging current (I) calculated by the first monitoring unit (56) by the other monitoring unit (60) of the electrical device (16).

3. The method according to claim 1 or 2, characterized in that, The first monitoring unit (56) is capable of matching the replaceable battery pack (10) to amplify the measured charging or discharging current (I) or the voltage value (U) derived from the charging or discharging current. Charge The amplifier circuit (80) makes the voltage value (U) Charge When the voltage exceeds its measurement range, the voltage value within the measurement range (U) is obtained. Charge ).

4. The method according to claim 2, characterized in that, If the calculated and measured charging or discharging currents (I) differ from each other by a defined difference (I0). Diff If the charging or discharging process is interrupted or reduced by the other monitoring unit (60), and / or the fault status of the replaceable battery pack (10) is notified by a signal.

5. The method according to claim 2, characterized in that, If the calculated and measured charging or discharging currents (I) differ from each other by more than 0.5A, the other monitoring unit (60) will stop or reduce the charging or discharging process and / or signal the fault status of the replaceable battery pack (10).

6. A system for performing the method according to any one of the preceding claims, the system comprising a replaceable battery pack (10) having a first monitoring unit (56) and a first electromechanical interface (14) having a plurality of electrical contacts (12), and the system comprising an electrical device (16) having another monitoring unit (60), a first current measuring device (84) and another electromechanical interface (24), the electrical device being a charging device (18), a diagnostic device (20) or a power consumer (22), the other electromechanical interface having a plurality of electrical contacts (12), wherein, Each of the first electrical contacts (12) of the interfaces (14, 24) is configured as an energy supply contact (42) capable of being loaded with a first reference potential (V1), each of the second electrical contacts (12) of the interfaces (14, 24) is configured as an energy supply contact (44) capable of being loaded with a second reference potential (V2), and each of the third electrical contacts (12) of the interfaces (14, 24) is configured as a signal or data contact (78), the signal or data contact being used to transmit the charging or discharging current (I) measured by the first current measuring device (84) of the electrical device (16) or the voltage value (U) derived from the charging or discharging current. Charge The first monitoring unit (56) is transmitted to the replaceable battery pack (10), wherein the electrical contacts (12) of the first and another electromechanical interfaces (14, 24) are capable of connecting to perform the method according to any one of the preceding claims.

7. The system according to claim 6, characterized in that, The replaceable battery pack (10) has a measurement amplifier (80) which is connected on the input side to the third electrical contact (12) of the first electromechanical interface (14) configured as a signal or data contact (78) and on the output side to the first monitoring unit (56).

8. The system according to claim 6, characterized in that, The first electromechanical interface (14) is constructed such that the third electrical contact (12) of the signal or data contact (78) is connected to the first monitoring unit (56) through a filter circuit (82) or directly.

9. The system according to any one of claims 6 to 8, characterized in that, The replaceable battery pack (10) has a resistive element (76) which is connected on one hand to the third electrical contact (12) of the first electromechanical interface (14) which is configured as a signal or data contact (78), and on the other hand to the second electrical contact (12) of the first electromechanical interface (14) which is configured as an energy supply contact (44).

10. The system according to claim 9, characterized in that, The resistive element (76) is configured as an coded resistor (76) for identifying the replaceable battery pack (10) in the power consumer (22).

11. The system according to claim 7, characterized in that, The measurement amplifier (80) of the replaceable battery pack (10) can be controlled by the first monitoring unit (56).

12. The system according to any one of claims 6 to 8, characterized in that, The first current measuring device (84) of the electrical equipment (16) has a first current measuring amplifier (86), which is connected to a first current sensor (88) on the input side. The first current sensor is connected to a second electrical contact (12) of the other electromechanical interface (24), which is configured as an energy supply contact (44). The first current measuring amplifier is connected to a third electrical contact (12) of the other electromechanical interface (24), which is configured as a signal or data contact (78), on the output side via a pull-up resistor (90).

13. The system according to claim 12, characterized in that, The first monitoring unit (56) of the replaceable battery pack (10) evaluates the charging or discharging current (I) calculated based on the resistance values ​​of the resistive element (86) and the pull-up resistor (90) known to the first monitoring unit and the current-voltage transfer function (102, 106) of the first current measuring device (84) of the electrical device (16) as permissible or not permissible.

14. The system according to claim 12, characterized in that, The electrical device (16) has a second current measuring device (92) for measuring the charging or discharging current (I) by means of a second current sensor (96), and the second current sensor is connected in series with the first current sensor (88) of the first current measuring device (84).

15. The system according to any one of claims 6 to 8, characterized in that, The first monitoring unit (56) of the replaceable battery pack (10) transmits the charging or discharging current (I) calculated by the first monitoring unit to another monitoring unit (60) of the electrical device (16) through the fourth electrical contact (12) of the interface (14, 24) configured as a signal or data contact (62), wherein the other monitoring unit (60) compares the calculated and measured charging or discharging current (I) with each other.

16. The system according to claim 6, characterized in that, The first reference potential (V1) is the supply potential (V + ).

17. The system according to claim 6, characterized in that, The second reference potential (V2) is the ground potential (GND).

18. The system according to claim 8, characterized in that, The filter circuit (82) is a diode.

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