WO2024074303A1

WO2024074303A1 - Method for analyzing the state of a rechargeable battery pack, analysis device, system, and computer program

Info

Publication number: WO2024074303A1
Application number: PCT/EP2023/075883
Authority: WO
Inventors: Andreas GONSER; Andrej Junginger; Khalil BEN CHIKHA
Original assignee: Robert Bosch Gmbh
Priority date: 2022-10-04
Filing date: 2023-09-20
Publication date: 2024-04-11
Also published as: DE102022210471A1

Abstract

The invention relates to a method for analyzing the state, in particular the health, of a rechargeable battery pack (16; 16a), in particular an exchangeable rechargeable battery pack (26; 26a), having the steps of: - detecting (100) at least one resistance characteristic; - ascertaining (102) at least one resistance on the basis of the resistance characteristic, - additionally detecting (104) at least one temperature characteristic; - additionally ascertaining (106) at least one temperature on the basis of the temperature characteristic; and - calculating (108) the SoH value of the rechargeable battery pack (16; 16a) while taking into consideration the at least one resistance and the at least one temperature.

Description

Method for analyzing a condition of a battery pack, analysis device, system and computer program

State of the art

It is generally known that a battery pack, or at least one of the battery cells in the battery pack, ages over time due to storage and/or use. A loss of capacity in the battery pack means that a fully charged battery pack no longer has the original running time or capacity available and can no longer provide it. In the case of battery packs that are permanently installed in devices and/or equipment, a continuous load profile, namely all charging and discharging processes of the battery pack, can be recorded in order to monitor the health of the battery pack and, preferably, to be able to analyze it at any time. In the case of battery packs designed as removable battery packs, the recording of a continuous load profile has so far only been possible with a sufficiently large memory in the battery pack, which has not yet been implemented. In the prior art, it is already known to determine the health status, namely an SoH value of a battery pack, using a method of electrochemical impedance spectroscopy or using so-called “column counting”. A disadvantage of the "columb counting" method is that the battery pack must be fully charged at least once beforehand, which takes more time and therefore the entire method for determining the state of health takes a relatively long time. Another disadvantage of the electrochemical impedance spectroscopy method is the additional hardware that is required to carry out this method. Disclosure of the invention

A method is proposed for analyzing a state, in particular a state of health, of a battery pack, in particular a removable battery pack, comprising;

- a detection step for detecting at least one resistance parameter;

- a determination step for determining at least one resistance based on the resistance parameter,

- a further detection step for detecting at least one temperature parameter;

- a further determination step for determining at least one temperature based on the temperature parameter; and

- a calculation step in which a SoH value of the battery pack is calculated taking into account at least one resistance and at least one temperature.

Such a method can be used to efficiently determine a state of health, namely a SoH value of a battery pack. In addition, the SoH value can be determined for battery packs, preferably removable battery packs, without continuously recording a load profile. Furthermore, the state of health can be determined using the present method, based on a mathematical method, in a simple, quick and/or convenient manner. In addition, the state of health can be determined within a short time, namely in no more than 2 minutes, advantageously in no more than 30 seconds, preferably in no more than 10 seconds. In addition, a calculation of the state of health of the battery pack can be made more precise and carried out more accurately. In addition, a computer program for carrying out the present method can be loaded onto existing hardware using a software update, so that additional devices and/or apparatus for carrying out the method can be dispensed with. This can increase efficiency in terms of cost and/or product and/or work efficiency.

Preferably, the present method is intended to prevent aging of the battery pack, in particular of at least one battery cell of the battery pack. determine and/or analyze. In particular, aging of the battery pack is indicated by at least an increase in cell resistance of at least the battery cell and/or an irreversible loss of capacity of the battery pack. The generally known SoH value ("State of Health" value) indicates the remaining running time or usable capacity in relation to the original running time/capacity in percent. In particular, the SoH value indicates the current health state of the battery pack. If, for example, a battery pack arranged in an electric saw can only saw 3 m of wood instead of the original 4 m, the SoH value of that battery pack is still 75% and the capacity of the battery pack has dropped by 25% over time.

The battery pack may possibly be designed as a permanently installed battery pack. The battery pack is particularly preferably designed as a removable battery pack and can advantageously be reversibly inserted into a consumer and/or reversibly connected to the consumer. The consumer is preferably designed as an electrically operated consumer which can be supplied with electrical energy by means of at least the battery pack. In particular, the consumer is designed as an electrical device. The consumer can be designed as a hand-held power tool, for example. A “hand-held power tool” is understood here to mean a machine tool for machining workpieces which can be transported and/or held by an operator without a transport machine. The hand-held power tool can be designed as a garden hand tool, for example as a lawn trimmer, namely as a brush cutter and/or brush cutter, as a hedge trimmer, as a leaf blower and/or as a chainsaw, etc. Alternatively, the consumer can also be an electrical household appliance, for example an electrical cleaning device, in particular a vacuum robot, and/or a lamp and/or a remote control. It would also be conceivable for the consumer to be a vehicle that can be operated at least partially electrically, for example an electric bicycle, in particular an e-bike, and/or an electric scooter and/or an electric car. The consumer is preferably a consumer with constant power consumption and/or continuous power use. Furthermore, any other designs of consumers that appear sensible to the expert are possible and conceivable. The present invention further relates to a system with at least one consumer, in particular the consumer mentioned above, and with a battery pack that can be connected to the consumer, in particular a removable battery pack that can be detachably connected, in particular the battery pack already mentioned. The system preferably has a control environment for determining the SoH value using the method mentioned. A "control environment" is to be understood as an electronic unit, in particular a control unit, which is intended to control and/or regulate at least one function of the battery pack, the consumer and/or a charger for the battery pack. The control environment advantageously comprises at least one computing unit, in particular a processor, and preferably in addition to the computing unit at least one storage unit with a control and/or regulating program stored therein, which is intended to be executed by the computing unit. The storage unit can be designed as a digital storage medium, for example as a hard disk or the like.

The battery pack can have a battery pack control unit, which can be at least partially part of the control environment or form this. Preferably, the consumer has a consumer control unit, which is at least partially part of the control environment or forms this. In particular, the control environment controls and/or regulates the method for determining the SoH value. The battery pack control unit and/or at least the consumer control unit can at least partially control and/or regulate the method with the respective method steps in order to carry out and/or execute the method for determining the SoH value. The battery pack control unit and at least the consumer control unit can communicate with each other, in particular wirelessly. Preferably, the system has a charger for at least the battery pack, in particular the removable battery pack. The charger can have a charger control unit. The charger control unit can be part of the control environment. The charger control unit and/or the battery pack control unit and/or at least the consumer control unit can communicate with each other, advantageously wirelessly, for example by means of a LAN, WLAN, WPAN, infrared, NFC, ZigBee, BLE and/or Bluetooth connection and/or via the Internet. The control environment particularly preferably has a battery management system (BMS). This enables and/or provides particularly efficient, precise and user-friendly monitoring and/or analysis of at least one state of a battery, namely a rechargeable battery. In particular, the battery management system is an electronic control circuit which can monitor charging and/or discharging of battery packs, for example removable battery packs, and/or ensure optimal use of battery cells in the battery pack. The battery pack control unit and/or at least the consumer control unit can at least partially have or form the battery management system. It would also be conceivable for the charger control unit to at least partially have or form the battery management system. Preferably, the battery management system is fully integrated in the battery pack or the charger. The battery management system can be provided to monitor at least one state of the battery pack and/or to carry out measurements, such as at least one current and/or voltage measurement, in particular to determine at least one resistance, during a charging and/or discharging process of the battery pack, in order to calculate at least the SoH value preferably with the parameters obtained and/or recorded by the measurement, such as resistance parameters and/or temperature parameters.

The control environment can start and/or end the method for analyzing the state of the battery pack. Preferably, the battery pack control unit communicates with at least the charger control unit to analyze the state of the battery pack when carrying out the method for analyzing the state. Particularly preferably, the battery pack control unit is provided to start and/or regulate and/or coordinate and/or end the method, in particular the individual method steps of the method. Alternatively and/or additionally, however, it would also be conceivable for the consumer control unit and/or the charger control unit to be provided to start and/or regulate and/or coordinate and/or end the method, in particular the individual method steps of the method. In particular, in the detection step, at least the resistance parameter on the battery cell of the battery pack is detected. The resistance parameter can be, for example, a voltage or a current or any other conceivable value from which and/or with which the resistance can be determined. Preferably, in the detection step, at least two resistance parameters of the battery cell are detected. The at least two resistance parameters can be two different resistance parameters, for example a first resistance parameter can be a current and a second resistance parameter can be a voltage. Alternatively and/or additionally, the at least two resistance parameters, in particular at least two identical or two different resistance parameters, can be detected on the battery cell at different times within the detection step. For example, at least the first resistance parameter, in particular a first voltage, can be detected at a first time, for example at the start of charging a charging process of the battery pack, and at least the second resistance parameter, in particular a second voltage, can be detected at a second time different from the first time, for example during the charging process of the battery pack, in the detection step. Furthermore, alternatively and/or additionally, a further first resistance parameter, for example a first current, can be detected at the first point in time and a further second resistance parameter, for example a second current value, can be detected at the second point in time. At least the resistance can be determined from the first resistance parameter and at least the second resistance parameter in the determination step.

The determination step advantageously takes place after the detection step with regard to a temporal progression of the method. In the determination step, the resistance can be determined at least for the battery cell, taking into account at least the resistance parameter. In particular, the resistance is an internal resistance of the battery cell. It would also be conceivable that several resistances of the battery cell can be determined at different times, for example during the charging process of the battery pack, within the determination step. In the determination step, for example, at least two resistances, advantageously at least four or six resistances of the battery cell could be determined. When determining several Resistances at different points in time, a large number of resistance parameters can be recorded at the respective different points in time in the recording step in order to be able to determine the large number of resistances in the determination step. This will be discussed in more detail later in this document.

With regard to the temporal progression of the method, the further recording step for recording at least the temperature characteristic of at least the battery cell can take place after the determination step. A "temperature characteristic" is a characteristic associated with at least one temperature, whereby the temperature characteristic can be any conceivable value with which and/or from which the temperature can be determined. For example, the temperature characteristic can be the temperature itself, advantageously a temperature of the battery cell measured at the intended installation location of a temperature sensor and/or a temperature measuring device, a time-dependent temperature profile and/or a temperature difference. Furthermore, the temperature characteristic could be an electrical voltage and/or an electrical current and/or an electrical resistance value which is correlated with a temperature, a time-dependent temperature profile and/or a temperature difference. The temperature characteristic could be determined, for example, using a thermistor (NTC) and/or a PTC thermistor (PTC). In the further detection step, several temperature parameters, namely at least two or four temperature parameters of the battery cell, could also be detected. The several temperature parameters can preferably be detected at different times within the further detection step. Alternatively and/or additionally, at least one temperature parameter of the plurality of temperature parameters could be detected per repetition of the further detection step. After detecting at least the temperature parameter, the further determination step for determining at least the temperature can be carried out based on the temperature parameter. The temperature can be a temperature at a specific time, an average temperature, a limit temperature, such as a maximum temperature, or the like.

Preferably, the battery pack, in particular the battery pack control unit, is designed to detect the at least one resistance parameter and/or to detect the at least one temperature parameter. Alternatively and/or additionally, the charger can be designed to detect the at least one resistance parameter and/or to detect the at least one temperature parameter. In addition, it would also be conceivable that the consumer is designed and/or provided to detect the at least one resistance parameter and/or to detect the at least one temperature parameter in a state electrically connected to the battery pack.

It would also be conceivable that the further recording step for recording at least the temperature parameter and/or the further determination step for determining at least the temperature can take place and/or be carried out before the recording step for recording at least the resistance parameter and/or the determination step for determining at least the resistance. In the present case, terms such as "further", which precede certain terms, are used only to differentiate between objects and/or process steps and do not imply any existing total number and/or ranking of the objects and/or process steps. It is possible that the recording step and/or at least the determination step can be carried out at the same time, namely at the same time parallel to the further recording step and/or further determination step. The calculation step is particularly preferably carried out only after the recording step, the determination step, the further recording step and at least the further determination step have been carried out.

Preferably, an analysis device is provided for carrying out the calculation step. All necessary formulas and/or variables and/or further information that are required to calculate the SoH value taking into account the at least one resistance and at least one temperature can be stored in the analysis device, at least partially and advantageously. The analysis device is particularly preferably part of the system. The analysis device can be at least partially part of the control environment. The analysis device could also be part of the battery management system. It would be conceivable for the analysis device to be at least partially or completely integrated in the battery pack, in particular the battery pack control unit and/or the charger, in particular the charger control unit. Preferably, the analysis environment is at least partially and advantageously completely integrated in the consumer, in particular the consumer control unit. Alternatively and/or additionally, it would also be possible for the analysis device to be at least partially or completely integrated in an external device and/or an external server, such as in a cell phone, a smartphone, a tablet, a laptop and/or the like.

Depending on where the analysis device is integrated, the battery pack, in particular the battery pack control unit, and/or the consumer, in particular the consumer control unit, and/or the charger, in particular the charger control unit, and/or the external device can communicate with each other in order to provide data, in particular at least the determined resistance and/or at least the determined temperature, for calculating the SoH value in the calculation step of the analysis device. It would be conceivable that the recorded resistance parameter, the recorded temperature parameter, the determined resistance and/or at least the determined temperature are stored and/or saved in a database environment. The database environment can be part of the control environment and at least partially integrated, for example, in the battery pack and/or in the consumer and/or in the charger and/or possibly also in the external device. Preferably, the database environment is at least largely or completely integrated in the battery pack, in particular in the battery pack control unit. It would also be conceivable that the database environment is at least partially integrated in a private and/or public server, for example a private and/or public server on the Internet. The database environment can also at least partially comprise a private and/or public cloud or be designed in this way. The database environment is preferably designed as a dedicated computer system or as at least part of a dedicated computer system.

In particular, in the calculation step, the SoH value is calculated using the following general formula

where “n” is the battery cell number “n” with n=1,...,n _max , where “n _max ” is the number of battery cells in the battery pack connected in series, “DCIR” is the resistance per battery cell, determined in particular in the determination step, “U” is a voltage per battery cell at a first point in time ti, in particular a start time of the charging or discharging process, and “b” is a specific coefficient, which will be discussed in more detail later. The voltage “U” can, for example, be recorded during the recording step when at least the resistance parameter is recorded. The SoH value is particularly preferably calculated in the calculation step within a short time, namely within a maximum of 5 minutes, advantageously within a maximum of 2 minutes, preferably within a maximum of 1 minute and particularly preferably within a maximum of 30 seconds.

It is further proposed that in the detection step a voltage change of at least one battery cell of the battery pack is detected at different charging currents or discharging currents. This can further increase efficiency with regard to detecting at least one resistance parameter.

In the detection step, at least two resistance parameters can be detected at different times. For example, during the charging process of the battery pack, a first charging current can be detected at a first time ti, advantageously at the start time when the charging process begins, and a second charging current can be detected at a further time ts that is different from the first time ti. Alternatively, in the detection step, during a discharging process of the battery pack, a first discharging current could be detected at a first time ti, advantageously at the start time when the discharging process begins, and a second discharging current could be detected at a further time ts that is different from the first time ti. Particularly preferably, the second resistance parameter at the second time, in particular later than the first time, preferably the second charging current and/or the second discharging current, has a value that is greater than zero.

Preferably, the resistance (“DCIR”) is determined in the determination step using the following formula:

In the formula just mentioned, “U” is a resistance parameter present as a voltage recorded at the respective different points in time, namely at the first point in time ti and at the second point in time tj. In particular, “I” is a resistance parameter present as a current recorded at the respective different points in time, namely at the first point in time ti and at the second point in time ts.

The detection step, the determination step, the further detection step, the further determination step and/or the calculation step can each take place during and/or immediately after the charging process and/or discharging process of the battery pack. Particularly preferably, at least the detection step, the determination step, the further detection step and/or the further determination step take place during the charging process of the battery pack.

It is also proposed that in the determination step at least two resistances of the battery cell are determined at different times. This allows a method for analyzing a state, and also for determining an SoH value of a battery pack, to be further optimized and efficiency to be further increased. By recording several identical and/or different types of resistance parameters per battery cell at different times in the recording step or in several recording steps, several, namely at least two resistances per battery cell can be determined at different times in the determination step. For example, as already described, in the recording step at least the first resistance parameter, in particular the first voltage, can be recorded at the first time, for example at the start of the charging process of the battery pack, and the second resistance parameter, in particular the second voltage, at the second time different from the first time, for example during the charging process of the battery pack, and/or the further first resistance parameter and/or at least the further second resistance parameter can be recorded. In addition, in the recording step at least a third resistance parameter, in particular a third voltage, can be recorded at a third time, in particular with regard to a temporal progression, for example during the charging process, after the second point in time, and at least a fourth resistance parameter, in particular a fourth voltage, at a fourth point in time different from the third point in time, in particular during the charging process of the battery pack. A first resistance can be determined in the determination step from at least the first resistance parameter and at least the second resistance parameter. A second resistance can be determined in the determination step or in a repetition of the determination step from at least the third resistance parameter and at least the fourth resistance parameter. In the determination step or by repeating the determination step, at least two resistances, advantageously at least four resistances and preferably at least five resistances, could be determined.

According to the following formula, the SoH value can be calculated based on several resistances per battery cell of the battery pack in the calculation step

where “n” is the battery cell number “n” with n=l,...,n _max , where “ _n max” is the number of battery cells in the battery pack connected in series and “m” is the determined resistance value number “m” with m=l...m _max , where “rn _max ” is the number of determined resistance values per cell. Furthermore, “DCIR” is the resistance per battery cell determined, in particular in one of the determination steps, “U” is a voltage per battery cell at a first point in time ti, in particular a start time of the charging process or discharging process, and “b” is a specific coefficient. Furthermore, “X” is an integer dependent on “n” and “m”. In this case, the SOH value can be calculated using an exponential function, but a calculation using polynomial functions or the like would also be conceivable.

The battery pack can have at least two battery cells, in particular at least three battery cells, preferably at least five battery cells and particularly preferably at least ten battery cells. The detection step, the determination step, the further detection step and/or at least the further determination step can be carried out for all battery cells in the battery pack, preferably simultaneously, in particular at the same time. The calculation step for calculating the SoH value could then take into account all battery cells in the battery pack, in particular the values determined for each battery cell when calculating the SoH value.

If the determination of the resistance and/or the determination of the temperature is carried out for all battery cells of the battery pack and the calculation step is limited to a smaller number of battery cells, a particularly efficient method can be provided and an SoH value of a battery pack can be calculated quickly and/or in a resource-saving manner. This in turn can increase overall efficiency and improve comfort for an operator.

If the battery pack has, for example, at least three battery cells, the detection step, the determination step, the further detection step and/or at least the further determination step can be carried out for all three battery cells of the battery pack and the subsequent calculation step can, however, only be limited to one battery cell of the three battery cells, for example, and in particular only take into account at least the determined resistance and/or at least the determined temperature of one battery cell when calculating the SoH value. Alternatively, it would also be conceivable that, if the battery pack has several battery cells, the determination of the resistance and/or the determination of the temperature is already limited to a smaller number of battery cells than the battery pack has battery cells. If the battery pack has, for example, three battery cells, the determination of the resistance and/or the determination of the temperature, in particular the detection step, the determination step, the further detection step and/or at least the further determination step, can only be carried out for at least one battery cell of the three battery cells of the battery pack.

It is also proposed that in the detection step at least one resistance parameter is detected for each battery cell of the battery pack. This allows a method for analyzing a condition, namely a state of health of a battery pack, to be further optimized and made more precise. In particular For each battery cell of the battery pack, the detection step and/or at least the further detection step for detecting at least the temperature parameter is carried out.

In order to provide an optimized, fast and/or resource-saving method for analyzing a condition, namely a state of health, and to further increase efficiency, it is proposed that in the determination step the resistance of a battery cell of the battery pack which has the lowest voltage and/or the highest internal resistance, in particular the highest resistance parameter, is determined. If in the detection step at least one resistance parameter, preferably at least one voltage, is detected for each battery cell of the battery pack, in the subsequent determination step only the resistance can be determined based on at least the detected resistance parameter of that battery cell of the battery pack which has the lowest voltage, preferably the lowest resistance parameter, and/or the highest internal resistance, in particular the highest resistance parameter.

Based on at least one determined resistance, and advantageously also at least one determined temperature, of only the weakest battery cell of the battery pack, the SoH value can be calculated in the calculation step. This simplifies the SOH formula already mentioned to

SOH = b _± + b ₂ * exp[ö ₃ * U + b * T + b ₅ * DCIR ] + f(dU) , where “DCIR” is the determined resistance of the weakest battery cell, “U” is a voltage of the battery cell at a first time ti, in particular a start time of the charging process or discharging process of the battery pack, and “b” is a specific coefficient. Furthermore, “dU” is a degree of de-balancing, which corresponds in particular to a voltage difference between the battery cell with the lowest voltage and the battery cell with the highest voltage. Preferably, the degree of de-balancing is used in the calculation step for calculating the SoH value. Furthermore, “f(dU)” can be determined by existing measurement data, for example recorded voltage values at the Battery cells of the battery pack can be mathematically approximated at different times.

In particular, there are different definitions for the dependence of the SOH value on the debalancing “f(dU)”:

Furthermore, it is proposed that at least one coefficient of a formula used to calculate the SoH value in the calculation step is determined using a machine learning method. This makes it possible to provide a particularly efficient and/or convenient method for analyzing a state, namely a state of health of a battery cell.

In particular, at least the aforementioned specific coefficient “b” is calculated and/or determined using the machine learning method. It may also be conceivable that the machine learning method is applied in the calculation step, namely the calculation of the SoH value. The machine learning method can be, for example, a linear regression, a classic machine learning algorithm such as “support vector machines”, a statistical method such as “bagging” or “random forest” based on so-called “decision trees”, a Gaussian process, a symbolic regression. Furthermore, the machine learning method could be based on an artificial neural network such as “freed-forward NNS” and/or “long-short-term memory networks” (LSTMs), and at least partially contribute to the calculation of the SoH value in the calculation step. In particular, before the SoH value can be calculated in the calculation step, the aforementioned coefficients “b” must be determined for the battery pack type in question. To do this, as many batteries with a known SOH as possible are measured, and the respective parameters, such as the resistance parameter and/or the temperature parameter, are determined. The coefficients “b” are determined from a large number of already known SOH values and parameters of battery packs. The determined coefficients “b” are preferably stored and/or saved in a database, for example an app, a cloud, a storage unit or the like, and can preferably be used in the calculation step to calculate the SOH value. If the coefficients “b” are known and the parameters have been determined, the calculation of the SOH using the methods already mentioned is very efficient, convenient and fast. Particularly preferably, any smartphone or the like can calculate the SOH value.

If the machine learning method is self-learning, efficiency can be increased even further and the determination of at least one coefficient of a formula for calculating the SoH value can be carried out even faster and/or more user-friendly.

The machine learning method can already be trained ex works, on a large number of battery packs with known SOH values. Furthermore, the machine learning method can be self-learning over the entire service life of the battery pack in question, for example at least in the calculation step. In particular, the machine learning method can be further trained in the field in order to optimize the coefficients "b". For this purpose, the parameters, such as the resistance values and/or the temperature parameters, which are obtained in the described method, are stored, for example, in a cloud or another database environment and used there to optimize for "b". Consequently, when using and/or utilizing the battery pack, either only the SOH value can be determined with known coefficients "b" or the parameters determined can be used in addition to optimize "b", in particular the latter only if the SOH value can still be determined using another method, such as using Coulomb counting. In particular, the machine learning algorithm is a deep learning algorithm. A self-learning process could take place according to the symbolic approach, in which knowledge, both examples and induced rules, are explicitly represented. It could be supervised or unsupervised learning. In supervised learning, the algorithm can learn a function from given pairs of inputs and outputs. In particular, the goal of supervised learning is that the algorithm is trained to make associations after several calculations with different inputs and outputs. Furthermore, the machine learning method could further optimize and improve itself using feedback from the operator. Alternatively, the self-learning process could also take place according to the non-symbolic approach. In the non-symbolic approach, the neural network can be "trained" to behave in a predictable manner, but this does not allow any insight into the learned solution paths, whereby the knowledge is implicitly represented. Furthermore, the machine learning method can be self-learning according to the so-called ADAM method or batch gradient method.

Furthermore, the invention relates to a computer program comprising instructions which, when the computer program is executed by a computer, cause the computer to carry out the described method for analyzing a state of a battery pack, in particular of the battery pack mentioned. In particular, the described method is designed as a computer-implemented method.

The method for analyzing a state of a battery pack, the analysis device, the system and/or the computer program should not be limited to the application and embodiment described above. In particular, the method for analyzing a state of a battery pack, the analysis device, the system and/or the computer program can have a number of individual elements, components, units and method steps that differs from the number mentioned here in order to fulfill a function described herein. In addition, the In addition to the range of values specified in the document, values within the limits specified are also deemed to be disclosed and can be used as desired.

Drawing

Further advantages emerge from the following description of the drawing. The drawing shows two embodiments of the invention. The drawing, the description and the claims contain numerous features in combination. The person skilled in the art will also expediently consider the features individually and combine them into further useful combinations.

Show it:

Fig. 1 a system comprising a battery pack designed as a removable battery pack, a charger and a consumer,

Fig. 2 is a schematic flow diagram of a method for analyzing a state of the battery pack, namely for determining a remaining running time of the battery pack,

Fig. 3 is a schematic flow diagram of a method for determining a SoH value of the battery pack and

Fig. 4 shows a system in an alternative embodiment, wherein the system has a removable battery pack, a charger, a consumer and a database environment comprises a cloud.

Description of the embodiments

The following figures are schematic representations and not to scale.

Figure 1 shows a system 10 with a charger 14 for a battery pack 16. The system 10 has the battery pack 16, which is designed as a removable battery pack 26. The removable battery pack 26 is detachable, namely reversibly can be used in at least one consumer 18 and/or reversibly connected to the consumer 18. In the present case, the consumer 18 is part of the system 10. The consumer 18 is an electrical device, for example a hand-held power tool, an electrical household appliance such as a vacuum robot or a lamp, or an electrically operated vehicle such as an electric bicycle or an electric scooter. Furthermore, the consumer 18 is a consumer with constant power consumption and/or continuous power use. The consumer 18 can be at least partially supplied with electrical energy by means of the battery pack 16 and/or can be operated in at least one operating state by means of electrical energy from the battery pack 16.

The system 10 has a control environment 50. The battery pack 16 has a battery pack control unit 36. The battery pack control unit 36 is part of the control environment 50. The charger 14 has a charger control unit 52. The charger control unit 52 is part of the control environment 50. Furthermore, the consumer 18 has a consumer control unit 56. The consumer control unit 56 is part of the control environment 50. The battery pack control unit 36, the charger control unit 52 and/or the consumer control unit 56 are provided to communicate with one another, in this case wirelessly.

The control environment 50 is provided here to carry out a method for analyzing a state of the battery pack 16, specifically the removable battery pack 26. The control environment 50 is provided here to carry out a method for determining a remaining running time of the battery pack 16. The remaining running time is, for example, a time, a distance, specifically a range, a number of work processes or the like.

To at least partially carry out the method for analyzing the state of the battery pack 16, the control environment 50 has a battery management system 60. The battery management system 60 is provided to monitor at least one state of the battery pack 16 and/or to carry out measurements, such as at least one current and/or voltage measurement, in particular to determine at least one resistance, during a charging and/or discharging process of the battery pack 16, in order to preferably to determine and/or calculate a remaining capacity and/or a capacity of the battery pack 16a, an SoC value, an SoH value and/or the remaining running time from the parameters obtained and/or recorded by the measurement, such as resistance parameters and/or temperature parameters. In this exemplary embodiment, the battery management system 60 is at least partially integrated in the consumer control unit 56 and at least partially in the battery pack control unit 36. It would also be conceivable for the battery management system 60 to be fully integrated in the consumer control unit 56.

The control environment 50 can start and/or end the method for analyzing the state of the battery pack 16. Furthermore, a computer program 70 comprises instructions which, when the computer program 70 is executed by a computer in the control environment 50, cause the computer to carry out the method for analyzing the state of the battery pack 16. The computer program 70 is at least partially integrated in the consumer control unit 56, the battery pack control unit 36 and/or the charger control unit 52.

In the present case, the consumer control unit 56 communicates with at least the battery pack control unit 36 to analyze the state of the battery pack 16 when carrying out the method for analyzing the state. The consumer control unit 56 is provided to start and/or regulate and/or coordinate and/or end the method, namely at least individual method steps of the method. Alternatively and/or additionally, the battery pack control unit 36 and/or the charger control unit 52 could be provided to start and/or regulate and/or coordinate and/or end the method, namely at least individual method steps of the method. In the present case, the consumer control unit 56 is provided to regulate and/or initiate and/or control measurements and/or recordings of parameters on the battery pack 16. The consumer 18 has measuring units and/or sensors which are part of the battery management system 60 in order to carry out measurements and/or detections of parameters, for example resistance parameters and/or temperature parameters, on the battery pack 16, specifically in an electrically connected state of the battery pack 16 with the consumer 18. The method for analyzing the state of the battery pack can comprise several method steps and/or method sub-steps. In the present case, the method has an SoC determination step 200 in which an SoC value of the battery pack 16 is determined (see Figure 2). In the present case, the consumer control unit 56 communicates with the battery pack control unit 36 in the SoC determination step 200 in order to determine the SoC value. A capacity and/or remaining capacity of the battery pack 16 can be determined in the SoC determination step 200 using the battery management system 60.

According to Figure 2, with regard to the temporal progression of the method, after the SoC determination step 200, an SoH determination step 202 takes place in which an SoH value of the battery pack 16 is determined. The following will discuss in detail how to determine the SoH value of the battery pack 16 and the various options for determining the SoH value. For this purpose, Figure 3 shows a schematic process flow diagram of a method for determining the SoH value of the battery pack 16.

According to Figure 3, the method for determining the SoH value of the battery pack 16 has a detection step 100 for detecting at least one resistance parameter. The resistance parameter is, for example, a voltage or a current. In this exemplary embodiment, in the detection step 100, a voltage change of at least one battery cell of the battery pack 16 is detected at different charging currents or discharging currents. In the present case, at least two resistance parameters of the battery cell are detected in the detection step 100. For example, in the detection step 100, at least a first resistance parameter, namely a first voltage at a first point in time, for example at the start of charging a charging process of the battery pack 16, and a second resistance parameter, namely a second voltage at a second point in time different from the first point in time, for example during the charging process of the battery pack 16, are detected. In this exemplary embodiment, the battery pack 16 has several battery cells. Furthermore, in the detection step 100, at least one resistance parameter is detected for each battery cell of the battery pack 16. According to Figure 3, with regard to a temporal progression of the method for determining the SoH value of the battery pack 16, after the detection step 100, a determination step 102 follows for determining at least one resistance based on the resistance parameter. In the present case, the resistance is an internal resistance of the battery cell. In the determination step 102, several resistances of the battery cell could be determined. In this exemplary embodiment, at least two resistances of the battery cell are determined at different times in the determination step 102. If several resistances are determined at different times, a large number of resistance parameters can be recorded at the respective different times in the detection step 100 in order to be able to determine the large number of resistances in the determination step 102. In order to provide a particularly efficient method, the resistance of a battery cell of the battery pack 16 that has the lowest voltage is determined in the determination step 102. The determination and/or selection of the weakest battery cell of the battery pack 16 can be carried out on the basis of the resistance parameters, for example the voltage, recorded in the recording step 100. The battery pack control unit 36 and/or the consumer control unit 56 and/or the charger control unit 52 are provided to determine and/or define and/or ascertain the weakest battery cell of the battery pack 16.

With regard to the temporal progression of the method, after the determination step 102, a further detection step 104 is carried out to detect at least one temperature parameter. The temperature parameter is a parameter associated with at least one temperature, whereby the temperature parameter can be any conceivable parameter with which and/or from which the temperature can be determined. For example, the temperature parameter is the temperature itself, a time-dependent temperature profile and/or a temperature difference. Furthermore, in a further determination step 106, which follows the further detection step 104, at least one temperature is determined based on the temperature parameter. In the present case, at least one temperature parameter is detected and a temperature is determined for each battery cell of the battery pack 16. In the present case, the battery pack 16 is designed to detect the at least one resistance parameter and to detect the at least one temperature parameter. Furthermore, the battery management system 60, which is at least partially integrated in the battery pack control unit 36, is designed to detect the at least one resistance parameter and to detect the at least one temperature parameter. The battery pack control unit 36 could independently carry out and/or start the steps for detecting the at least one resistance parameter and for detecting the at least one temperature parameter. Alternatively, the consumer control unit 56 is provided to start and/or regulate the detection step 100, the determination step 102, the further detection step 104 and/or the further determination step 106.

According to Figure 3, after the further determination step 106, a calculation step 108 takes place in which an SoH value of the battery pack 16 is calculated taking into account the at least one resistance and at least one temperature. In order to provide a particularly efficient and fast method, the resistance is determined in this case for all battery cells of the battery pack 16, although the calculation step 108 is limited to a smaller number of battery cells. Alternatively, the calculation step 108 could also take place for all battery cells of the battery pack 16 for which at least one resistance was determined.

The calculation step 108 can be carried out by the battery pack control unit 36, the charger control unit 52 and/or the consumer control unit 56. In the present case, the system 10 has an analysis device 12 for carrying out at least the calculation step 108. In this exemplary embodiment, the analysis device 12 is at least partially, and also completely, integrated in the consumer 18, namely the consumer control unit 56. Alternatively and/or additionally, it would also be possible for the analysis device 12 to be at least partially or completely integrated in the charger, and/or an external device and/or an external server, such as in a smartphone, a tablet, a laptop and/or the like. Furthermore, at least one coefficient of a formula used to calculate the SoH value in the calculation step 108 is determined using a machine learning method. To increase the efficiency of at least the calculation step 108, the machine learning method is self-learning.

After the SoH value has been successfully calculated, the SoH value can be stored and/or saved in a database environment 28. In the present case, the database environment 28 is at least largely or completely integrated in the battery pack 16 and also in the battery pack control unit 36. Alternatively and/or additionally, the database environment 28 could also be at least partially integrated in the consumer 18, namely the consumer control unit 56 and/or the charger 14, namely the charger control unit 52.

In the SoH determination step 202, the consumer 18 communicates with at least the database environment 28 to determine the SoH value. In the SoH determination step 202, the SoH value can be provided by the battery pack 16. The consumer 18, namely the consumer control unit 56, retrieves the SoH value from the database environment 28 in the SoH determination step 202. Alternatively, at least the resistance parameter, the resistance, the temperature parameter and/or the temperature can be stored and/or saved in the database environment 28, which could be recorded and/or averaged, for example, by the detection step 100, the determination step 102, the further detection step 104 and/or the further determination step 106. If the load 18 is electrically connected to the battery pack 16 or communicates wirelessly with the battery pack 16, the load 18, namely the load control unit 56, can determine the SoH value in the SoH determination step 202 based on data provided by the battery pack 16, namely the data stored in the database environment 28.

According to the method just described in Figure 3, in the SoH determination step 202, the SoH value can be determined based on at least one determined resistance parameter of at least one battery cell of the battery pack 16. Alternatively, in the SoH determination step 202, the SoH value could also be determined based on at least one change in a measured voltage of at least of a battery cell of the battery pack 16 over time with the same current flow. An estimate would simplify the SoH determination step 202, but the determined SoH value may be somewhat less accurate than after the calculation already described. Consequently, several procedures for determining the SoH value in the SoH determination step 202 are possible.

If the SoC determination step 202 and the SoH determination step 202 were carried out according to the method according to Figure 2, a remaining running time calculation step 204 is then carried out in which a remaining running time of the battery pack 16 is calculated taking into account the SoC value and the SoH value. Furthermore, in the remaining running time calculation step 204, a current measurement is carried out to record a current characteristic of the battery pack 16 and the current characteristic is taken into account when calculating the remaining running time. Alternatively, in the remaining running time calculation step 204, a voltage measurement is carried out to record a voltage characteristic of the battery pack 16 and the voltage characteristic is taken into account when calculating the remaining running time.

The remaining running time calculation step 204 can be carried out by the battery pack control unit 36, the charger control unit 52 and/or the consumer control unit 56. In the present case, the remaining running time calculation step 204 is carried out by means of the analysis device 12. In the present case, the battery pack control unit 36 communicates with the analysis device 12. In the present case, the battery pack control unit 36 communicates with the consumer control unit 56 in the remaining running time calculation step 204.

In order to output the remaining running time to a user, the system 10 has a remaining running time output 38 for outputting a remaining running time. Furthermore, the method according to Figure 2 has an output step 206 for outputting the remaining running time. The output step 206 takes place after the remaining running time calculation step 204. The battery pack control unit 36 and/or the consumer control unit 56 can initiate the output of the remaining running time. In this exemplary embodiment, the battery pack 16 has an output unit 30 which is provided for outputting the remaining running time in the output step 206. The output unit 30 is part of the remaining running time output 38. Alternatively and/or additionally, the consumer 18 could also have an output unit for outputting the Remaining running time, which is part of the remaining running time output 38. The remaining running time can be output to the user acoustically and/or visually.

Figure 4 shows a further embodiment of the invention. The following descriptions are essentially limited to the differences between the embodiments, whereby reference can be made to the description of the embodiment in Figures 1 to 3 with regard to identical components, features and functions. To distinguish the embodiments, the letter a is inserted into the reference numerals of the embodiment in Figure 4. With regard to components with the same designation, in particular with regard to components with the same reference numerals, reference can also be made to the drawings and/or the description of the embodiment in Figures 1 to 3.

Figure 4 shows a system 10a in an alternative embodiment. The system 10a has a battery pack 16a, which is also designed as a removable battery pack 26a, a charger 14a for the battery pack 16a and a consumer 18a. The system 10a also has a control environment 50a. The battery pack 16a has a battery pack control unit 36a. The battery pack control unit 36a is part of the control environment 50a. The charger 14a has a charger control unit 52a. The charger control unit 52a is part of the control environment 50a. The consumer 18a also has a consumer control unit 56a. The consumer control unit 56a is part of the control environment 50a. The battery pack control unit 36a, the charger control unit 52a and/or the consumer control unit 56a are intended to communicate with each other, in this case wirelessly.

To at least partially carry out a method for analyzing the state of the battery pack 16a, the control environment 50a has a battery management system 60a. The difference from the previously described embodiment according to Figures 1 to 3 is that the battery management system 60a is completely integrated in the battery pack 16a. Furthermore, in this exemplary embodiment, the battery pack 16a is provided to carry out and/or control necessary measurements and/or recordings of parameters of at least one battery cell of the battery pack 16a itself, and independently of a consumer control unit 56a. In the present case, the battery management system 60a integrated in the battery pack 16a, namely the battery pack control unit 36a, manages monitoring and/or analysis of the state of at least one cell, preferably all cells of the battery pack 16a. Furthermore, in this exemplary embodiment, the charger 14a is additionally designed to detect the at least one resistance parameter and/or to detect the at least one temperature parameter. The charger control unit 52a communicates with the battery pack control unit 36a, either in an electrically connected state, for example during the charging process, or wirelessly.

In addition, the present embodiment differs from the embodiment according to Figures 1 and 3 in a database environment 28a. While in the embodiment according to Figures 1 and 3 the database environment 28a was fully integrated in the battery pack 16a, the database environment 28a is at least partially integrated into a private and/or public server, for example a private and/or public server on the Internet. The database environment 28a here has a private and/or public cloud 24a.

Furthermore, the system 10a in the present case comprises an external device 20a, which in this exemplary embodiment is designed as a cell phone. An analysis device 12a of the system 10a is arranged at least partially in the external device 20a. In contrast to the embodiment according to Figures 1 and 3, the external device 20a carries out and/or carries out a calculation step for calculating a SoH value of the battery pack 16a and/or a remaining running time calculation step for calculating the remaining running time based on at least the SoH value and a SoC value of the battery pack 16a due to the integrated analysis device 12a. To obtain the SoH value and/or the SoC value and/or at least one parameter correlated with the SoH value and/or the SoC value, the external device 20a communicates, in the present case wirelessly, with the battery pack 16a, the consumer 18a, the charger 14a and/or the database environment 28a. The external device 20a is designed to, based on information provided by the battery pack 16a, the consumer 18a, the charger 14a and/or the database environment 28a, Data to carry out the calculation step for calculating the SoH value of the battery pack 16a and/or the remaining running time calculation step for calculating the remaining running time. After calculating the SoH value and/or the remaining running time, the external device 20a can transmit data to the battery pack 16a and/or the consumer 18a, for example to display the remaining running time. Alternatively and/or additionally, the external device 20a could also output the remaining running time, for example by displaying it.

Claims

Expectations

1. Method for analyzing a state, in particular a state of health, of a battery pack (16; 16a), in particular interchangeable battery packs (26; 26a), comprising;

- a detection step (100) for detecting at least one resistance characteristic;

- a determination step (102) for determining at least one resistance based on the resistance parameter,

- a further detection step (104) for detecting at least one temperature parameter;

- a further determination step (106) for determining at least one temperature based on the temperature parameter; and

- a calculation step (108) in which a SoH value of the battery pack (16; 16a) is calculated taking into account the at least one resistance and at least one temperature.

2. Method according to claim 1, characterized in that in the detection step (100) a voltage change of at least one battery cell of the battery pack (16; 16a) is detected at different charging currents or discharging currents.

3. Method according to claim 1 or 2, characterized in that in the determination step (102) at least two resistances of the battery cell of the battery pack (16; 16a) are determined at different times.

4. Method according to one of the preceding claims, characterized in that the determination of the resistance is carried out for all battery cells of the battery pack (16; 16a), wherein the calculation step (108) is limited to a smaller number of battery cells.

5. Method according to claim 4, characterized in that in the detection step (100) at least one resistance parameter is detected for each battery cell of the battery pack (16; 16a).

6. Method according to claim 4 or 5, characterized in that in the determination step (102) the resistance of a battery cell of the battery pack (16; 16a) which has the lowest voltage and/or a highest internal resistance is determined.

7. Method according to one of the preceding claims, characterized in that at least one coefficient of a formula which is used to calculate the SoH value in the calculation step (108) is determined by means of a machine learning method.

8. The method according to claim 7, characterized in that the machine learning method is self-learning.

9. Analysis device (12; 12a) for carrying out a calculation step (108) at least according to claim 1.

10. System (10; 10a) comprising an analysis device (12; 12a) according to claim 9 and a consumer (18; 18a), wherein the analysis device (12; 12a) is at least partially integrated in the consumer (18; 18a).

11. System (10) comprising an analysis device (12) according to claim 9 and a charger (14) for a battery pack (16), in particular a removable battery pack, wherein the battery pack (16) is designed to detect the at least one resistance parameter and/or to detect the at least one temperature parameter. System (10a) comprising an analysis device (12a) according to claim 9 and a charger (14a) for a battery pack (16a), in particular a removable battery pack, wherein the charger (14a) is designed to detect the at least one resistance parameter and/or to detect the at least one temperature parameter. Computer program (70) comprising instructions which, when the computer program is executed by a computer, cause the computer to carry out a method according to one of claims 1 to 8.