Method for controlling and regulating a rechargeable battery

Abstract

The present invention relates to a method for controlling and regulating a rechargeable battery, which rechargeable battery comprises at least one first and one second energy storage unit, control electronics, a voltage measuring device and at least one sensor device, wherein the sensor device and the energy storage units are connected to one another via at least one controllable switching element such that electrical energy can be conducted from the energy storage units to the sensor device. The method comprises the following method steps: using the voltage measuring device to capture a first voltage value of the first and second energy storage units; and if the difference between the voltage value of the first energy storage unit and the voltage value of the second energy storage unit reaches a predetermined threshold, adjusting the at least one switching element from a deactivated mode to an activated mode in order to conduct voltage from the energy storage unit having the higher voltage value to the sensor device.

Description

Technical Field

[0001] The present invention relates to a method for controlling and regulating a rechargeable battery having at least one first and one second energy storage unit, control electronics, a voltage measuring device, and at least one sensor device, wherein the sensor device and the energy storage units are connected to each other via at least one controllable switching element in such a way that electrical energy can be conducted from the energy storage units to the sensor device. Background Art

[0002] Modern rechargeable batteries contain a plurality of energy storage units, which can also be referred to as primary cells or rechargeable battery cells. In addition, modern rechargeable batteries usually also have a battery management system in order to monitor and regulate the functions and processes within the rechargeable battery. A balancer is usually an important part of the battery management system. The task of the balancer is to ensure that the charge is distributed as evenly as possible over all the energy storage units. However, the balancers of the energy storage units in rechargeable batteries according to the prior art are usually inefficient. Summary of the Invention

[0003] Accordingly, an object of the present invention is to provide a method for controlling and regulating a rechargeable battery, which can be used to improve the balancing and / or uniform charge distribution in the energy storage units of the rechargeable battery.

[0004] This object is accordingly achieved by a method for controlling and regulating a rechargeable battery according to the present invention.

[0005] This object is particularly achieved by a method for controlling and regulating a rechargeable battery having at least one first and one second energy storage unit, control electronics, a voltage measuring device, and at least one sensor device, wherein the sensor device and the energy storage units are connected to each other via at least one controllable switching element in such a way that electrical energy can be conducted from the energy storage units to the sensor device.

[0006] According to the present invention, the method comprises the following method steps:

[0007] - Capturing a first voltage value of the first and second energy storage units by means of the voltage measuring device; and

[0008] - If the difference between the voltage value of the first energy storage unit and the voltage value of the second energy storage unit reaches a predetermined threshold, adjusting the at least one switching element from a deactivated mode to an activated mode in order to conduct voltage from the energy storage unit having the higher voltage value to the sensor device.

[0009] According to an advantageous embodiment of the present invention, the method may comprise the following method steps:

[0010] After the end of the first cycle, the second voltage values of the first and second energy storage units are captured by the voltage measuring device.

[0011] This enables the voltage values of the individual energy storage units to be monitored regularly or irregularly and / or captured regularly in order to initiate a balancing process if necessary and to distribute the charge evenly among the energy storage units of the rechargeable battery.

[0012] According to an advantageous embodiment of the invention, the method may comprise the following method steps:

[0013] After the end of the second cycle, the second voltage values of the first and second energy storage units are captured by the voltage measuring device, wherein the second cycle depends on the difference between the voltage value of the first energy storage unit and the voltage value of the second energy storage unit.

[0014] This enables the monitoring or capture of the voltage values of the individual energy storage units to be adapted to how quickly the charges in the individual energy storage units change relative to each other.

[0015] The switching element may be a metal-oxide-semiconductor field-effect transistor (MOSFET) or another suitable field-effect transistor (FET). Description of the Drawings

[0016] Further advantages can be found in the following description of the drawings. Multiple different exemplary embodiments of the invention are shown in the drawings. The drawings, the description and the claims contain many combinations of features. A person skilled in the art will also conveniently consider these features individually and combine them into useful further combinations.

[0017] In the drawings:

[0018] Figure 1 A side view of a power tool with a rechargeable battery for performing the method according to the invention is shown;

[0019] Figure 2 A cross-sectional view of a rechargeable battery with a plurality of energy storage units, a control device, a voltage measuring device and a sensor device is shown;

[0020] Figure 3 A circuit diagram for performing the method according to the invention is shown; and

[0021] Figure 4 A graphical illustration of the ratio of the variation of the second cycle to the voltage variation is shown. Detailed Description

[0022] Figure 1Shows a power tool 1 and a rechargeable battery 2. The power tool 1 is shown in the form of a screwdriver operated by a rechargeable battery. According to other alternative embodiments, the power tool 1 can also be designed in the form of a power drill, saw, grinder, etc.

[0023] The rechargeable battery 2 is connected to the power tool 1 via an interface 3 and is used to supply electrical energy to the electrical load of the power tool 1. During supply, current flows from the rechargeable battery 2 to the power tool 1.

[0024] The power tool 2 designed to be a screwdriver operated by a rechargeable battery generally includes a housing 4, a handle 5, a base 6, a tool fitting 7, an electric drive 8 in the form of an electric motor, a controller 9, a transmission mechanism 10, an input shaft 11, an output shaft 12, and an activation switch 13. The electric motor can be a brushless electric motor.

[0025] The electric drive 8 designed as an electric motor, the transmission mechanism 10, the input shaft 11, the output shaft 12, and the controller 9 are located within the housing 4. The drive 8, the transmission mechanism 10, the input shaft 11, and the output shaft 12 are positioned relative to each other and are located within the housing 10 such that the torque generated by the drive 8 is transmitted to the output shaft 12. The output shaft 12 transmits the torque to the transmission mechanism 10, which in turn transmits the torque to the input shaft 11. The tool fitting 7 is driven by the input shaft 11 by transmitting torque. As Figure 1 shown, a tool in the form of a bit is held in the tool fitting 7. With the aid of the bit, a screw can be screwed into the material. The tool, the screw, and the material are not shown in the drawings.

[0026] As Figure 1 also shown, the housing 4 includes a top side 4a and a bottom side 4b. The handle 5 includes a first end 5a and a second end 5b. The first end 5a of the handle 5 is fixed to the bottom side 4b of the housing 4. In addition, the base 6 includes an upper end 6a and a lower end 6b. The upper end 6a of the base 6 is fixed to the second end 5b of the handle 5. The lower end 6b of the base 6 includes an interface 15 and is used to make mechanical, electrical, and electronic connections between the power tool 2 and the rechargeable battery 2. In this case, the connection can be released again.

[0027] To receive electrical energy (or current), the interface 15 includes a plurality of power connections. The interface 15 also includes a data connection for sending and receiving information and data in the form of signals.

[0028] Can be from Figure 1It is derived from that the controller 9 of the power tool 1 is positioned in the handle 5 of the power tool 1. The controller 9 of the power tool 1 is used to control and regulate various processes related to the power tool 1 and related to the rechargeable battery 2. The controller 9 particularly controls the current or current intensity flowing from the rechargeable battery 2 to the power tool 1 and particularly used to drive the driver 8 formed as an electric motor. In addition, the controller 9 is also used to capture the voltage applied by the rechargeable battery.

[0029] In this case, the controller 9 of the power tool 2 includes a microcontroller 18 (also known as MCU) and a data interface that is part of the communication circuit for two-way communication between the rechargeable battery 2 and the power tool 1. Neither the data interface nor the communication circuit is shown in the drawings.

[0030] The rechargeable battery 2 generally includes a housing 21 having a rechargeable battery interface 22, and a plurality of energy storage units 23. The energy storage units 23, control electronics 24 having a microcontroller 25, a voltage measuring device 26, and a sensor device 27 are positioned in the housing 21 of the rechargeable battery 2.

[0031] The sensor device 27 can be, for example, an acceleration sensor, a GPS sensor (Global Positioning System sensor), a gyroscope sensor, a temperature sensor, or other sensors that require almost continuous power supply for proper and permanent functions.

[0032] The control electronics 24 can also be referred to as a battery management system.

[0033] The rechargeable battery 2 also includes a data interface that is part of the communication circuit for two-way communication between the rechargeable battery 2 and the power tool 1. The data interface of the rechargeable battery 2 is not shown in the drawings.

[0034] The energy storage unit 23 can also be referred to as a rechargeable battery unit and is used to extract, store, and provide electrical energy or voltage. The energy storage unit 23 is a unit based on lithium-ion technology, where each rechargeable battery unit has a voltage between 2.7 V and 4.2 V.

[0035] The rechargeable battery interface 22 is positioned on one side of the housing 21. The rechargeable battery interface 22 includes a plurality of power connectors for extracting and delivering current, and also includes a data connector for transmitting and receiving signals between the power tool 1 and the rechargeable battery 2. The current from the energy storage unit 23 can be delivered through the power connectors. The data connector is not shown in the drawings.

[0036] The power connectors of the rechargeable battery 2 are connected to the power connection of the power tool 2. Similarly, the data connectors of the rechargeable battery 2 are connected to the data connection of the power tool 1.

[0037] Upon connection, electrical energy can flow from the energy storage unit 23 of the rechargeable battery 2 to the power tool 1. Additionally, signals can be exchanged between the rechargeable battery 2 and the power tool 1 for communication purposes.

[0038] As can be taken from Figure 2 and Figure 3 it follows that each energy storage unit 23 is connected to the control electronics 24 and the voltage measuring device 26 via a controllable switching element 30, respectively. Due to this connection, the voltage measuring device 26 can capture or measure the voltage at each individual energy storage unit 23.

[0039] In the exemplary embodiment cited, the controllable switching element 30 is in the form of a MOSFET. The switching element 30 can be controlled by a signal or a current and can be reversibly set to an active mode or an inactive mode. The control is achieved by the control electronics 24. In the inactive mode, the switching element 30 is set in such a way that the electrical circuit is open and the electrical circuit is thus interrupted. In contrast, in the active mode, the switching element is set in such a way that the electrical circuit is closed.

[0040] An uneven distribution of charge in the rechargeable battery cells 23 can be captured by the voltage measuring device 26 and the control electronics 24. However, there is an uneven distribution of charge in the rechargeable battery cells 23 only when a predetermined threshold is reached or a predetermined threshold of the charge difference between two rechargeable battery cells 23 is reached. To distribute the charge as evenly as possible in the rechargeable battery cells 23, the switching element 30 connected to the rechargeable battery cell 23 with the highest state of charge is controlled by these control electronics 24. Controlling the switching element 30 closes the switching element 30 and the corresponding circuit, with the result that electrical energy flows from the rechargeable battery cell 23 with the highest charge state to these control electronics 24. The electrical energy is conducted from the control electronics 24 to the sensor device 27 and is thus used to supply electrical energy to the sensor device 27.

[0041] The voltage or state of charge of each individual rechargeable battery cell 23 is captured or measured at regular time intervals.

[0042] According to a further embodiment, the voltage ΔV or state of charge ΔQ (Ah) of each individual rechargeable battery cell 23 can also be captured or measured at irregular time intervals Δt (see Figure 4 ). For example, the time interval between a first capture operation and a second capture operation can depend on the difference between the highest state of charge of the first rechargeable battery cell 23 and the lowest state of charge of the second rechargeable battery cell 23. The greater the difference between the highest state of charge and the lowest state of charge, the shorter the time interval between the first operation and the second operation of capturing the voltage or state of charge of each individual rechargeable battery cell 23.

[0043] The time interval can also depend on an increase in the difference between the highest state of charge and the lowest state of charge of the rechargeable battery unit 23. The faster the difference between the highest state of charge and the lowest state of charge, the shorter the time interval between the first operation and the second operation for capturing the voltage or state of charge of each rechargeable battery unit 23.

[0044] Furthermore, if the control electronics 24 has started the regulation of different states of charge (balancing of the rechargeable battery units 23), then the time interval can depend on a decrease in the difference between the highest state of charge and the lowest state of charge of the rechargeable battery unit 23. In other words: the faster the regulation between the highest state of charge and the lowest state of charge, the shorter the time interval between the first operation and the second operation for capturing the voltage or state of charge of each rechargeable battery unit 23.

Claims

1. A method for controlling and regulating a rechargeable battery (2), the rechargeable battery having at least a first energy storage unit and a second energy storage unit (23), control electronics (24), a voltage measuring device (26) and at least one sensor device (27), wherein, the sensor device (27) and the energy storage units (23) are respectively connected to each other via at least one controllable switching element (30) in such a way that electrical energy can be conducted from the energy storage units (23) to the sensor device (27), characterized by the following method steps - capturing a first voltage value of the first energy storage unit and the second energy storage unit (23) by means of the voltage measuring device (26); and - if the difference between the voltage value of the first energy storage unit (23) and the voltage value of the second energy storage unit (23) reaches a predetermined threshold, adjusting the at least one switching element (30) from a deactivated mode to an activated mode in order to conduct voltage from the energy storage unit (23) having the higher voltage value to the sensor device (27); - after the end of a second period, capturing a second voltage value of the first energy storage unit and the second energy storage unit (23) by means of the voltage measuring device (26), wherein the second period depends on the difference between the voltage value of the first energy storage unit (23) and the voltage value of the second energy storage unit (23).

2. The method according to claim 1, characterized in that, after the end of a first period, capturing a second voltage value of the first energy storage unit and the second energy storage unit (23) by means of the voltage measuring device (26).

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